The invention generally relates to an electronic control unit for vehicles. More particularly
the invention relates to a system for driving and controlling of all the LED lamp loads present
in a vehicle.
BACKGROUND OF THE INVENTION
Over the years, there has been tradition to use Bulb lamp loads for lighting in vehicles, which
includes Head lamp, Stop Lamp, Tail Lamp, Right-Left Turn Signal Winkers and License
Lamp. Bulb lamp loads can be driven directly through battery with the help of Regulator
rectifier and small individual driving circuits. A Bulb lamp load is resistive in nature which
illuminates according to its rated wattage. Moreover, bulb load loses a lot of energy in the
form of heat and it doesn’t have long life. Thus, they have to be replaced after a year or less.
However, current through a bulb is not regulated, it can vary according to the source. Like in
the prior applications, Head lamp is driven through Regulator rectifier, which recharges
battery and provides output load current. Intensity of head lamp varies according to the speed
of the vehicle. This made necessity of some new kind of lamps which saves power and also
do have wide and constant intensity as well.
Additionally, in another application to achieve constant intensity of lamp load, each
individual lamp load requires independent driver to regulate current through it. This increases
the cost of lamp load as a whole product. If the lamp load gets damaged in any case, then user
has to replace the old lamp with driver with new one even if lamp load driver is found to be
working.
Light emitting diode i.e. LEDs are becoming more popular alternative of regular bulb lamps.
A LED lasts much longer than a bulb and saves more power as compared to the later. But,
unlike a bulb, a LED lamp load cannot be driven directly through battery. As a LED is
current controlled device, it requires current regulating circuit to maintain constant current
flow through it and hence provide fixed illumination. Purchasing individual LED load lamp
driver adds an additional cost for the vehicle manufacturer, which is drawback to use LEDs
as an alternative to regular bulbs.
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Accordingly, there lies a need for central system that can control functionality and drive all
the LED load lamps and/ or Bulb load lamps, depending upon the OEM requirements, as
well. This system will enable OEMs to use LED lamp load without drivers.
It is an object of the invention to provide an integrated central system that drives LED lamp
loads and controls their functionality on the basis of various inputs of the vehicle.
SUMMARY OF INVENTION
This summary is provided to introduce a selection of concepts in a simplified format that is
further described in the detailed description of the invention. This summary is neither
intended to identify key or essential inventive concepts of the invention and nor is it intended
for determining the scope of the invention.
Accordingly, the present invention provides a device (152) for illuminating one or more
LED-based vehicular lamps (150, 151, 132-141) forming part of a vehicle, the device (152)
forming part of a circuit comprising a power source; plurality of LED-based vehicular lamps
(150, 151, 132-141); and plurality of switches (144-149) for controlling illumination state of
a LED-based vehicular lamp corresponding thereto, the device (152) comprising: an input
voltage sensing component (112) for sensing an amount of input voltage and generating an
input voltage indicating signal corresponding thereto; an engine parameter sensing
component (108) for sensing a parameter pertaining to an engine of the vehicle and
generating an engine parameter indicating signal corresponding thereto; plurality of switch
sensing components (102-107) for sensing status of each of the plurality of switches (144-
149) and generating switch state indicating signals corresponding thereto; plurality of fault
detection components (115, 125-128) for sensing fault in the LED-based vehicular lamps
(150, 151, 134-137) and generating fault indicating signals corresponding thereto; a
microcontroller (100) adapted to receive the input voltage indicating signal, the engine
parameter indicating signal, the switch state indicating signals, and the fault indicating signals
and based thereupon generate one or more LED lamp control signals; and plurality of driver
components (114, 116-124, 129-131) adapted to receive the LED lamp control signal from
the microcontroller and cause illumination of the LED-based vehicular lamp (150, 151, 132-
141) connected thereto.
In an embodiment of the invention, the one or more LED-based vehicular lamps (150, 151,
132-141) include:
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LED-based High-beam lamp (150);
LED-based Low-beam lamp (151);
LED-based Switch Illumination lamp (132);
LED-based Position indicating lamp (133);
LED-based Left-front Winker lamp (134);
LED-based Right-front Winker lamp (135);
LED-based Left-rear Winker lamp (136);
LED-based Right-rear Winker lamp (137);
LED-based Stop (Brake) / Tail lamp (138);
LED-based Right Winker Cluster indicator lamp (139);
LED-based Left Winker Cluster indicator lamp (140); and
LED-based high beam cluster indicator lamp (141).
In an embodiment of the invention, the one or more switches (144-149) include:
a High-Beam / Low-Beam Switch (144);
a Pass-beam Switch (145);
a Right Winker Switch (146);
a Left Winker Switch (147);
a Brake / Stop Switch (148); and
a Hazard Switch (149).
In an embodiment of the invention, the switch sensing components (102-107) include:
a High-Beam / Low-Beam Switch sensing component (102);
a Pass-beam Switch sensing component (103);
a Right Winker Switch sensing component (104);
a Left Winker Switch sensing component (105);
a Brake / Stop Switch sensing component (106); and
a Hazard Switch sensing component (107).
In an embodiment of the invention, the power source includes:
a battery (109); and
a combination comprising an alternating current (AC) generator (143) and an AC-DC
converter (142).
In an embodiment of the invention, the fault detection components (115, 125-128) include:
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head lamp fault detection component (115);
left font winker LED short detection component (125);
right front winker LED short detection component (126);
left rear winker LED short detection component (127); and
right rear winker LED short detection component (128).
In an embodiment of the invention, the driver components (114, 116-124, 129-131) include:
High-beam LED Lamp driver component (114);
Low-beam LED lamp driver component (116);
A Buck converter component (117);
Switch Illumination LED lamp driver component (118);
Position indicating LED lamp driver component (119);
Left-front LED Winker lamp driver component (120);
Right-front LED Winker lamp driver component (121);
Left-rear LED Winker lamp driver component (122);
Right-rear LED Winker lamp driver component (123);
Stop (Brake) / Tail LED lamp driver component (124);
Right Winker Cluster indicator lamp driver component (129);
Left Winker Cluster indicator lamp driver component (130); and
High beam cluster indicator lamp driver component (131).
In an embodiment of the invention, the device further comprises:
an input voltage protection component (101) for protecting the device (152) from damage in
case of reverse battery voltage and transient pulses; and
a regulated power supply component (113) for operating the microcontroller (100) and other
components.
In an embodiment of the invention, the Input Voltage protection component (101) comprises
a MOSFET (Q14), a combination of resistors (R235 & R236) for turning on the MOSFET, a
Diode (D20) and Zener diode (Z22) to protect MOSFET (Q14) from reverse and overvoltage, a polarised bulk Capacitor (C127) for providing stable input voltage in battery-less
condition, a combination of capacitors (C128, C130 and C164) and a power inductor (L6) for
minimizing EMI/EMC noise, and a Transient voltage suppressor diode (D23) for suppressing
transient pulses that may be generated in vehicle.
6
In an embodiment of the invention, the regulated power supply component (113) is
configured to provide a 5V signal to the microcontroller (100) and other components, and
wherein the regulated power supply component (113) comprises a voltage regulator IC (U2)
having load dump protection, a first capacitor (C18) as a voltage stabilizer at input terminal
of the voltage regulator (U2), a second capacitor (C17) adapted to filter and stabilize voltage
at the output terminal of the voltage regulator (U2), a third capacitor (C19) for filtering noise
at the output terminal of the voltage regulator (U2), a resistor (R18) for discharging the
second & third capacitor (C17 & C19) when there is no voltage at the input terminal of the
voltage regulator IC (U2), and a diode (D13) to provide path for reverse current which
protects the voltage regulator (U2) from damage.
In an embodiment of the invention, each of the plurality of driver components (114, 116-124,
129-131) is based on MOSFETs & Transistors (Q2, Q3, Q23, Q27, Q5, Q6, Q7, Q8, Q9,
Q10, Q11, Q12, Q17 Q19, Q24, Q25, Q28 and Q29 ), inductors (L5 and L4), and driving ICs
(U3, U4, U5, U7, U8 and U10).
In an embodiment of the invention, the power source is connected to the device (152) via a
DC line.
In an embodiment of the invention, the High-Beam / Low-Beam Switch (144), the Passing
beam input switch (145), the Right winker input switch (146), the Left winker input switch
(147), the Brake/Stop input switch (148) and the Hazard input switch (149) are directly
connected to the DC line.
In an embodiment of the invention, the input voltage sensing component (112) comprises a
combination of resistors (R20, R22 and R28) as a voltage divider for converting input voltage
to a pre-defined value, a Zener diode (Z4) for clamping sensed input voltage, and a capacitor
(C26) as a filter and a voltage stabilizer at ADC pin of the microcontroller (100).
In an embodiment of the invention, the High-Beam / Low-Beam Switch sensing component
(102) comprises a diode (D5) for reverse voltage protection, a resistor (R192) to generate
required minimum operating current for the switch, a Zener diode (Z5) to clamp switch
sensed voltage at an ADC pin of the microcontroller (100), a plurality of resistors (R31, R33
and R36) as voltage divider for converting switch voltage to pre-defined value, and a
capacitor (C28) for filtering noise signal at the ADC pin of the microcontroller (100).
7
In an embodiment of the invention, the Pass-beam Switch sensing component (103)
comprises a first diode (D6) for reverse voltage protection, a resistor (R193 and R42) to
generate required minimum operating current for the switch, a Zener diode (Z7) to clamp
switch sensed voltage at the ADC pin of the microcontroller (100), a plurality of resistors
(R40, R41 and R43) as voltage divider for converting switch voltage to pre-defined value,
and a capacitor (C31) for filtering noise signal at the ADC pin of the microcontroller (100).
In an embodiment of the invention, the Right Winker Switch sensing component (104)
comprises a diode (D8) for reverse voltage protection, a resistor (R194) to generate required
minimum operating current for the switch, a Zener diode (Z9) to clamp switch sensed voltage
at the ADC pin of the microcontroller (100) , a plurality of resistors (R52, R53 and R55) as
voltage divider for converting switch voltage to pre-defined value, and a capacitor (C34) for
filtering noise signal at the ADC pin of the microcontroller (100).
In an embodiment of the invention, the Left Winker Switch sensing component (105)
comprises a diode (D9) for reverse voltage protection, a resistor (R195) to generate required
minimum operating current for the switch, a Zener diode (Z10) to clamp switch sensed
voltage at the ADC pin of the microcontroller (100) , a plurality of resistors (R57, R58 and
R60) as voltage divider for converting switch voltage to pre-defined value, and a capacitor
(C35) for filtering noise signal at the ADC pin of the microcontroller (100).
In an embodiment of the invention, the Brake / Stop Switch sensing component (106)
comprises a diode (D11) for reverse voltage protection, a resistor (R197 and R69) to generate
required minimum operating current for the switch, a Zener diode (Z12) to clamp switch
sensed voltage at the ADC pin of the microcontroller (100) , a plurality of resistors (R67, R68
and R70) as voltage divider for converting switch voltage to pre-defined value, and a
capacitor (C37) for filtering noise signal at the ADC pin of the microcontroller (100).
In an embodiment of the invention, the Hazard Switch sensing component (107) comprises a
first diode (D10) for reverse voltage protection, a resistor (R196 and R64) to generate
required minimum operating current for the switch, a Zener diode (Z11) to clamp switch
sensed voltage at the ADC pin of the microcontroller (100) , a plurality of resistors (R62, R63
and R65) as voltage divider for converting switch voltage to pre-defined value, and a
capacitor (C36) for filtering noise signal at the ADC pin of the microcontroller (100).
8
In an embodiment of the invention, the engine parameter sensing component (108) comprises
a diode (D34) or a resistor (R289) for reverse voltage protection, a Zener diode (Z6) to clamp
switch sensed voltage at ADC pin of the microcontroller (100) , a plurality of resistors (R34,
R37 and R38), pulled up by power supply (113), as voltage divider for converting engine
status signal voltage to pre-defined value, a capacitor (C30) for filtering noise signal at ADC /
Interrupt pin of the microcontroller (100) and a capacitor (C29) for filtering noise signal at
input status signal.
In an embodiment of the invention, the head lamp fault detection component (115) comprises
a combination of resistors (R8, R10 and R15) as voltage divider for converting LED load
voltage to pre-defined value, a Zener diode (Z2) to clamp switch sensed voltage at the ADC
pin of the microcontroller (100) and a capacitor (C12) for filtering noise signal at the ADC
pin of the microcontroller (100).
In an embodiment of the invention, the left font winker LED short detection component (125)
comprises a comparator (U5) driven through the power supply (113), a first combination of
resistors (R80 and R86) as a voltage divider for sensing LED load voltage at positive
reference of the comparator (U5), a second combination of resistors (R84 and R87) as a
voltage divider pulled up by power supply (113) for maintaining negative reference of
comparator, a resistor (R83) to limit current to an interrupt pin of the microcontroller (100)
and a capacitor (C40) for filtering noise signal at the interrupt pin of the microcontroller
(100).
In an embodiment of the invention, the right front winker LED short detection component
(126) comprises a comparator (U5) driven through power supply (113), a first combination of
resistors (R92 and R99) as voltage divider for sensing LED load voltage at positive reference
of the comparator, a second combination of resistors (R96 and R100) as voltage divider
pulled up by power supply (113) for maintaining negative reference of comparator, a resistor
(R95) to limit current to an interrupt pin of the microcontroller (100) and a capacitor (C42)
for filtering noise signal at the interrupt pin of the microcontroller (100).
In an embodiment of the invention, the left rear winker LED short detection component (127)
comprises a comparator (U5) driven through power supply (113), a first combination of
resistors (R113 and R119) as voltage divider for sensing LED load voltage at positive
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reference of comparator, a second combination of resistors (R117 and R120) as voltage
divider pulled up by power supply (113) for maintaining negative reference of comparator, a
resistor (R116) to limit current to an interrupt pin of the microcontroller (100) and a capacitor
(C47) for filtering noise signal at the interrupt pin of the microcontroller (100).
In an embodiment of the invention, the right rear winker LED short detection component
(128) comprises a comparator (U5) driven through power supply (113), a first combination of
resistors (R127 and R131) as voltage divider for sensing LED load voltage at positive
reference of comparator, a second combination of resistors (R130 and R132) as voltage
divider pulled up by power supply (113) for maintaining negative reference of comparator, a
resistor (R128) to limit current to an interrupt pin of the microcontroller (100) and a capacitor
(C49) for filtering noise signal at the interrupt pin of the microcontroller (100).
In an embodiment of the invention, the High-beam LED Lamp driver component (114)
provides constant current to Headlamp LED (150 and 151) of the vehicle, said High-beam
LED Lamp driver component (114) comprises:
a Buck- boost controller / H –Bridge IC (U10);
a power inductor (L5) for H-bridge (Buck-boost) operation;
a combination of MOSFETs (Q23 and Q3) as high side and low side switches for buck-boost
operation;
a parallel combination of bulk capacitor (C148 and C170) to provide ripple-less and constant
current;
a further bulk capacitor (C103) to provide stable input voltage in case of battery less
condition;
a parallel combination of capacitors ( C104, C105, C106, C108, C162 and C165) to filter
output noise;
a plurality of capacitors (C110 and C117) to filter out noise at input and output lines of the
Buck- boost controller / H-Bridge IC (U10);
a combination of a capacitor (C115) and a resistor (R281) or a diode (D24) for input voltage
sensing in the Buck- boost controller / H-Bridge IC (U10);
a diode (D21) to protect the Buck- boost controller / H-Bridge IC (U10) from reverse voltage;
a resistor (R225) to configure mode of operation of the Buck- boost controller / H-Bridge IC
(U10);
a combination of capacitors (C118 and C161) for frequency dithering;
10
a resistor (R226) to configure adjustable regulating frequency of the Buck- boost Controller /
H-Bridge IC (U10);
a capacitor (C116) to configure soft-start time for the Buck- boost controller / H-Bridge IC
(U10);
a capacitor (C120) to configure slope compensation for operation of the Buck- boost
controller / H-Bridge IC (U10);
a combination of resistor (R24) and capacitors (C121 and C119) for output of error amplifier
& compensate for error feedback of loop for operation of the Buck- boost controller / HBridge IC (U10);
a combination of resistors (R25 and R35) to provide output voltage feedback for operation of
the Buck- boost controller / H-Bridge IC (U10);
a combination of resistors (R264, R263 and R267) and a capacitor (C174) to switch On/Off
the Buck- boost controller / H-Bridge IC (U10) depending on input voltage;
a transistor (Q27) to enable the Buck- boost controller / H-Bridge IC (U10);
a combination of resistor (R217 and R262) for biasing transistor (Q27);
a capacitor (C174) to filter noise at transistor (Q27);
a combination of resistors (R233 and R234) and a capacitor (C122) to provide feedback to
the Buck- boost controller / H-Bridge IC (U10) for constant current loop for output load;
a resistor (R215) to configure constant current output;
a resistor (R229) to limit over-current flow through power inductor (L5);
a resistor (R227) for internal operation of the Buck- boost controller / H-Bridge IC (U10);
a capacitor (C113) for filtering noise at Vcc of the Buck- boost controller / H-Bridge IC
(U10);
a plurality of resistors (R19, R218, R219 and R224) for current limiting during switching of
MOSFET;
a combination of resistor (R251 and R252), capacitor (C111 and C112) and diode (D7 and
D14) for switching of MOSFET; and
a diode (D26) as Reverse-voltage protection.
In an embodiment of the invention, the Low-beam LED lamp driver component (116) is
driven by the High-beam LED Lamp driver component (114) and provides switching
between High beam LEDs and Low beam LEDs, said Low-beam LED lamp driver
component (116) comprises:
a MOSFET (Q2) as a switch to change LED mode;
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a combination of resistors (R21 and R189) for biasing the MOSFET (Q2);
a transistor (Q17) to control switching of MOSFET (Q2);
a combination of resistors (R190 and R191) for biasing transistor (Q17);
a Zener diode (Z18) to protect MOSFET (Q2) Source to Gate from over-voltage;
a combination of resistor (R188) and capacitors (C71 and C173) for increasing switching
time of MOSFET (Q2);
a plurality of capacitors (C93, C72, C176 and C177) as noise filters at output and transistors;
a combination of transistors (Q28 and Q29) to force shut down the MOSFET (Q2) in LED
make & break condition;
a combination of resistors (R278 and R279) for biasing transistor (Q29);
a combination of resistor (R275) and a Zener diode (Z23) for biasing and turn ON transistor
(Q28) above certain voltage;
a combination of resistors (R271, R274 and R276) for translating LED voltage in make &
break condition; and
a diode (D25) as reverse voltage protection.
In an embodiment of the invention, the Buck converter component (117) provides constant
voltage to each of the Switch Illumination LED lamp driver component (118); the Position
indicating LED lamp driver component (119); the Left-front LED Winker lamp driver
component (120); the Right-front LED Winker lamp driver component (121); the Left-rear
LED Winker lamp driver component (122); the Right-rear LED Winker lamp driver
component (123); the Stop/Tail LED lamp driver component (124); said Buck converter
component (117) comprises:
a step down switching voltage regulator IC (U3) as constant voltage source for constant
current LED drivers (118-124);
a pair of capacitors (C21 and C22) as noise filter in input supply line of the step down
switching voltage regulator IC (U3);
a capacitor (C24) as noise filter in output line of the step down switching voltage regulator IC
(U3);
a resistor (R26) to configure regulation frequency of the step down switching voltage
regulator IC (U3);
a capacitor (C25) for soft start of the step down switching voltage regulator IC (U3);
a combination of resistors (R259, R260 and R268) and a capacitor (C175) to switch On/Off
the step down switching voltage regulator IC (U3) depending on input voltage;
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a power inductor (L4) for stepping down battery voltage and providing constant voltage for
constant current drivers;
a bulk capacitor (C23) for stable and ripple less constant voltage;
a combination of a resistor (R213) and a capacitor (C20) for efficient switching of inbuilt
MOSFET of the step down switching voltage regulator IC (U3);
a diode (D4) as a freewheeling diode for voltage regulation of the step down switching
voltage regulator IC (U3); and
a combination of resistors (R23 and R27) for providing output voltage feedback to the step
down switching voltage regulator IC (U3).
In an embodiment of the invention, each of the Left-front LED Winker lamp driver
component (120); the Right-front LED Winker lamp driver component (121); the Left-rear
LED Winker lamp driver component (122); and the Right-rear LED Winker lamp driver
component (123) is driven by the Buck converter component (117) to provide constant
current to Left front winker LED (134), Right Front winker LED (135), Left Rear winker
LED (136) and Right rear winker LED (137).
In an embodiment of the invention, the Left-front LED Winker lamp driver component (120);
the Right-front LED Winker lamp driver component (121); the Left-rear LED Winker lamp
driver component (122); and the Right-rear LED Winker lamp driver component (123)
comprises:
a linear current driver IC (U4) as constant current source for LEDs (134-137);
a capacitor (C39) as noise filter in input supply line of the linear current driver IC (U4);
a combination of resistors (R76 and R269) for protecting MCU pin and to detect LED open
fault condition;
a combination of capacitors (C83 and C84) as noise filters at feedback pins of the linear
current driver IC;
a combination of resistors ( R85, R88, R94 and R101) as current setting elements;
a combination of transistors (Q5, Q6, Q7 and Q8) as ON/OF switch for winker LEDs (134-
137);
a diode (D30, D31, D32 and D35) or resistor (R282, R283, R284 and R285) as reverse
voltage protection; and
a combination of capacitors (C150, C166, C151, C167, C86, C168, C89 and C169) as noise
filters at LED output.
13
In an embodiment of the invention, the Stop/Tail LED lamp driver component (124) is driven
by the Buck converter component (117) to provide constant current to stop/tail LED (138),
said Stop/Tail LED lamp driver component (124) comprises:
a linear current driver IC (U7)as constant current source for LEDs (138);
a first capacitor (C52) as noise filter in input supply line of the linear current driver IC (U7);
a combination of resistors (R141 and R143) for protecting MCU pin and to detect LED open
fault condition;
a combination of capacitors (C80 and C95) as noise filters at feedback pins of the linear
current driver IC;
a combination of resistors ( R150, R151, R152 and R153) as current setting elements;
a pair of transistors (Q11 and Q24) as ON/OF switch for stop and tail LEDs (138);
a diode (D27) or resistor (R286) as reverse voltage protection; and
a combination of capacitors (C54and C55) as noise filters at LED output.
In an embodiment of the invention, each of the Switch Illumination LED lamp driver
component (118) and the Position indicating LED lamp driver component (119) is driven by
the Buck converter component (117) to provide constant current to switch illumination LED
(132) and position LED (133), the Switch Illumination LED lamp driver component (118)
and the Position indicating LED lamp driver component (119) comprising:
a linear current driver IC (U8) as constant current source for LEDs (132 and 133);
a first capacitor (C62) as noise filter in input supply line of the linear current driver IC (U8);
a combination of resistors (R171 and R173) for protecting MCU pin and to detect LED open
fault condition;
a combination of capacitors (C81 and C96) as noise filters at feedback pins of the linear
current driver IC (U8);
a combination of resistors ( R177, R178, R179 and R180) as current setting elements;
a pair of transistors (Q19 and Q25) as ON/OF switch for switch illumination and position
LEDs (132-133);
a Zener diode (Z19) to distribute power dissipation at switch illumination LED;
a diode (D28 and D29) or resistor (R287and R288) as reverse voltage protection; and
a combination of capacitors (C64, C172, C97 and C171) as noise filters at LED output.
In an embodiment of the invention, the right winker cluster indicator lamp driver component
(129) comprises:
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a transistor (Q9) acting as an ON/OFF switch for LED-based right winker cluster indicator
lamp (141);
a resistor (R135) as current limiter through transistor(Q9) during ON time;
a combination of resistors (R136 and R140) for biasing transistor (Q9); and
a combination of capacitors (C53 and C98) as noise filters.
In an embodiment of the invention, the Left Winker Cluster indicator lamp driver component
(130) comprises:
a transistor (Q10) acting as an ON/OFF switch for the LED-based Left Winker Cluster
indicator lamp (140);
a resistor (R144) as current limiter through transistor(Q10) during ON time;
a combination of resistors (R147 and R149) for biasing transistor (Q10); and
a combination of capacitors (C56 and C91) as noise filters.
In an embodiment of the invention, the High Beam Cluster indicator lamp driver component
(131) comprises:
a transistor (Q12) acting as an ON/OFF switch for the LED-based High Beam Cluster
indicator lamp (139);
a resistor (R154) as current limiter through transistor(Q12) during ON time;
a combination of resistors (R157 and R159) for biasing transistor (Q12); and
a combination of capacitors (C58 and C92) as noise filters;
In an embodiment of the invention, the microcontroller (100) is a 16-bit microcontroller,
wherein a combination of a first diode (D12), a resistor (R181), and a capacitor (C66) is used
for RESET pin of the microcontroller (100), wherein a second capacitor (C67) is used as an
Internal Work at a REGC pin of the microcontroller (100), wherein a third capacitor (C65)
may be used as a filter for noise signal and as a voltage stabilizer at a input supply pin of the
microcontroller (100), a combination of resistors (R182 and R183) pulled up by regulated
power supply (113) for external crystal pins of microcontroller (100) and wherein a connector
(J2) is used for programming the microcontroller (100).
To further clarify the advantages and features of the present invention, a more particular
description of the invention will be rendered by reference to specific embodiments thereof,
which is illustrated in the appended drawings. It is appreciated that these drawings depict
only typical embodiments of the invention and are therefore not to be considered limiting of
15
its scope. The invention will be described and explained with additional specificity and detail
with the accompanying drawings.
BREIF DESCRIPTION OF ACCOMPANYING DRAWINGS:
These and other features, aspects, and advantages of the present invention will become better
understood when the following detailed description is read with reference to the
accompanying drawings in which like characters represent like parts throughout the
drawings, wherein:
Figure 1 illustrates a block diagram of the device (152) for driving and controlling all
LED load lamps used in vehicle, in accordance with an embodiment of the invention;
Figure 2 illustrates an elaborate view of the input voltage protection component
forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 3 illustrates an elaborate view of the input voltage sensing component (112)
forming part of the device (152), in accordance with an exemplary embodiment of the
invention.
Figure 4 illustrates an elaborate view of the High Beam / Low-Beam switch sensing
component (102) forming part of the device (152) in accordance with an exemplary
embodiment of the invention;
Figure 5 illustrates an elaborate view of the Pass-beam Switch sensing component
(103) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 6 illustrates an elaborate view of the Right Winker Switch sensing component
(104) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 7 illustrates an elaborate view of the Left Winker Switch sensing component
(105) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 8 illustrates an elaborate view of the Brake / Stop Switch sensing component
(106) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 9 illustrates an elaborate view of the Hazard Switch sensing component (107)
forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
16
Figure 10 illustrates an elaborate view of the engine parameter sensing component
(108) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 11 illustrates an elaborate view of the regulated power supply component
(113) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 12 illustrates an elaborate view of the microcontroller (100) and its peripheral
circuit forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 13 illustrates an elaborate view of the High-beam LED Lamp driver
component (114) forming part of the device (152) in accordance with an exemplary
embodiment of the invention;
Figure 14 illustrates an elaborate view of the head lamp fault detection component
(115) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 15 illustrates an elaborate view of the Low-beam LED lamp driver component
(116) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 16 illustrates an elaborate view of the Buck converter component (117)
forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
Figure 17 illustrates an elaborate view of the Left-front LED Winker lamp driver
component (120); the Right-front LED Winker lamp driver component (121); the Left-rear
LED Winker lamp driver component (122); and the Right-rear LED Winker lamp driver
component (123) forming part of the device (152) in accordance with an exemplary
embodiment of the invention;
Figure 18 illustrates an elaborate view of the left font winker LED short detection
component (125); the right front winker LED short detection component (126); the left rear
winker LED short detection component (127); and the right rear winker LED short detection
component (128) forming part of the device (152) in accordance with an exemplary
embodiment of the invention;
Figure 19 illustrates an elaborate view of the Stop/Tail LED lamp driver component
(124) forming part of the device (152) in accordance with an exemplary embodiment of the
invention;
17
Figure 20 illustrates an elaborate view of the Switch Illumination LED lamp driver
component (118); and Position indicating LED lamp driver component (119) forming part of
the device (152) in accordance with an exemplary embodiment of the invention;
Figure 21 illustrates an elaborate view of the Right Winker Cluster indicator lamp
driver component (129) forming part of the device (152) in accordance with an exemplary
embodiment of the invention;
Figure 22 illustrates an elaborate view of the Left Winker Cluster indicator lamp
driver component (130) forming part of the device (152) in accordance with an exemplary
embodiment of the invention; and
Figure 23 illustrates an elaborate view of the High beam cluster indicator lamp driver
component (131) forming part of the device (152) in accordance with an exemplary
embodiment of the invention.
It may be noted that to the extent possible, like reference numerals have been used to
represent like elements in the drawings. Further, those of ordinary skill in the art will
appreciate that elements in the drawings are illustrated for simplicity and may not have been
necessarily drawn to scale. For example, the dimensions of some of the elements in the
drawings may be exaggerated relative to other elements to help to improve understanding of
aspects of the invention. Furthermore, the one or more elements may have been represented
in the drawings by conventional symbols, and the drawings may show only those specific
details that are pertinent to understanding the embodiments of the invention so as not to
obscure the drawings with details that will be readily apparent to those of ordinary skill in the
art having benefit of the description herein.
DEATILED DESCRIPTION
For the purpose of promoting an understanding of the principles of the invention, reference
will now be made to the embodiment illustrated in the drawings and specific language will be
used to describe the same. It will nevertheless be understood that no limitation of the scope of
the invention is thereby intended, such alterations and further modifications in the illustrated
system, and such further applications of the principles of the invention as illustrated therein
being contemplated as would normally occur to one skilled in the art to which the invention
relates.
It will be understood by those skilled in the art that the foregoing general description and the
following detailed description are exemplary and explanatory of the invention and are not
18
intended to be restrictive thereof. Throughout the patent specification, a convention employed
is that in the appended drawings, like numerals denote like components.
Reference throughout this specification to “an embodiment”, “another embodiment” or
similar language means that a particular feature, structure, or characteristic described in
connection with the embodiment is included in at least one embodiment of the invention.
Thus, appearances of the phrase “in an embodiment”, “in another embodiment” and similar
language throughout this specification may, but do not necessarily, all refer to the same
embodiment.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a
non-exclusive inclusion, such that a process or method that comprises a list of steps does not
include only those steps but may include other steps not expressly listed or inherent to such
process or method. Similarly, one or more devices or sub-systems or elements or structures
proceeded by "comprises... a" does not, without more constraints, preclude the existence of
other devices or other sub-systems.
Embodiments of the invention will be described below in detail with reference to the
accompanying drawings.
Figure 1 illustrates a block diagram of a device 152 for controlling all LEDs present in a
vehicle. In one embodiment, the device 152 comprises plurality of sensing components 102-
108 & 112, an input voltage protection component 101, a microcontroller 100, plurality of
driver components 114, 116, 117-124 & 129-131, a regulated power supply component 113,
and plurality of LED fault detection components 125-128 & 115.
The microcontroller (100) receives signals from the eight sensing components 102-108 and
112, processes these signals, determines fault in LED through fault detection components
(125-128 and 115) and accordingly provides control instructions to the driver components
(114, 116-124 & 129-131) in order to automatically switch-on or switch-off LED loads of the
vehicle.
In particular, the plurality of sensing components 102-108 & 112 include:
• an input voltage sensing component (112) for sensing an amount of input voltage and
generating an input voltage indicating signal corresponding thereto;
19
• an engine parameter sensing component (108) for sensing a parameter pertaining to an
engine of the vehicle and generating an engine parameter indicating signal
corresponding thereto; and
• plurality of switch sensing components (102-107) for sensing status of each of the
plurality of switches (144-149) and generating switch state indicating signals
corresponding thereto.
In an embodiment of the invention, the input voltage protection component (101) is
configured to protect the device (152) from damage in case of reverse battery voltage and
transient pulses.
In an embodiment of the invention, the plurality of switch sensing components (102-107)
include:
• a High-Beam / Low Beam Switch sensing component (102);
• a Pass-beam Switch sensing component (103);
• a Right Winker Switch sensing component (104);
• a Left Winker Switch sensing component (105);
• a Brake / Stop Switch sensing component (106); and
• a Hazard Switch sensing component (107).
In an embodiment of the invention, the plurality of driver components (114, 116, 117-124 &
129-131) include:
• High-beam LED Lamp driver component (114);
• Low-beam LED lamp driver component (116);
• A Buck converter component (117);
• Switch Illumination LED lamp driver component (118);
• Position indicating LED lamp driver component (119);
• Left-front LED Winker lamp driver component (120);
• Right-front LED Winker lamp driver component (121);
• Left-rear LED Winker lamp driver component (122);
• Right-rear LED Winker lamp driver component (123);
• Stop/Tail LED lamp driver component (124);
• Right Winker Cluster indicator lamp driver component (129);
• Left Winker Cluster indicator lamp driver component (130); and
20
• High beam cluster indicator lamp driver component (131).
It may be noted that one or more of the plurality of driver components may share one or more
components, thereby minimizing the number of components involved in making the device
and minimizing the cost of the device. For instance, the Left-front LED Winker lamp driver
component (120); the Right-front LED Winker lamp driver component (121); the Left-rear
LED Winker lamp driver component (122); and the Right-rear LED Winker lamp driver
component (123) may share one more components. By way of another instance, the Switch
Illumination LED lamp driver component (118) and the Position indicating LED lamp driver
component (119) may share one more components.
In an embodiment of the invention, the plurality of fault detection components (115, 125-
128) include:
head lamp fault detection component (115);
left font winker LED short detection component (125);
right front winker LED short detection component (126);
left rear winker LED short detection component (127); and
right rear winker LED short detection component (128).

In another embodiment, the regulated power supply component 113 is configured to supply
regulated power, such as 5V supply to the microcontroller (100). The regulated power supply
component 113 derives power from the vehicle (either from the vehicle’s AC power
generator (143) using regulator rectifier (142) through input voltage protection circuit (101)
or the vehicle’s battery (109)).
Referring to Figure 2, there is illustrated an elaborate view of the input voltage protection
component (101) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The input voltage protection component (101) protects the
device (152) from reverse battery connection in accordance with an embodiment of the
invention. Particularly, the input voltage protection component (101) comprises an input
MOSFET Q14 which acts as reverse battery protection. MOSFET Q14 is turned on using a
resistor divider circuit which comprises of R235 (may have value of about 10K i.e. about 10
kilo ohm), and R236 (may have value of about 4.7K) and a diode D20. Gate to Source
terminals of MOSFET Q14 is protected against application of over-voltage using Zener diode
Z22 which may have clamping voltage of about 8.2V. Further, Transient voltage suppressor
21
diode D23 with working voltage of about 22V is used to protect the device (152) from
transient voltage pulses that may generate in vehicle. A bulk capacitor C127 (may have
capacitance value of about 220uF with working voltage of up to about 35V) is used to enable
device (152) to be in operational mode in battery-less condition. Moreover, an EMI noise
filter is used, comprising of an inductor L6 (may have value of about 6.8uH i.e. microHenry), a first capacitor C128 (may have capacitance value of about 470nF with working
voltage of about 50V), a second C130 (may have capacitance value of about 470nF with
working voltage of about 50V) and a third capacitor C164 (may have capacitance value of
about 10nF with working voltage of about 50V) on both sides of inductor, to counter balance
EMI/EMC emissions.
Referring to Figure 3, there is illustrated an elaborate view of the input voltage sensing
component (112) forming part of the device (152), in accordance with an exemplary
embodiment of the invention. In accordance with an embodiment of the invention, the input
voltage sensing component (112) senses voltage of the battery (109) in the vehicle when the
battery is connected through an ignition switch (111). The input voltage sensing component
(112) acts as an interface between the battery (109) and an ADC pin of the microcontroller
(100). As shown, the input voltage sensing component (112) comprises a combination of
resistors R20, R22 and R28 as a voltage divider for converting the voltage of the battery
(109) to a digital equivalent to a pre-defined value for the ADC pin of the microcontroller
(100). R20 and R22 may have a resistance value of about 30 K while R28 may have a
resistance value of about 15 K. The input voltage sensing component (112) further includes a
Zener diode Z4 for clamping the sensed battery voltage to the suitable voltage, such as about
5.1V, in order to protect the ADC pin of the microcontroller. The input voltage sensing
component (112) also includes a capacitor C26 that is used as a filter and as a voltage
stabilizer at the ADC pin of the microcontroller 100. C26 may have a capacitance value of
about 10nF and a working-voltage of about 50 V.
Referring to Figure 4, there is illustrated an elaborate view of the High Beam switch sensing
component (102) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. In accordance with an embodiment of the invention, the High
Beam switch sensing component (102) senses High beam switch input voltage of the vehicle.
The High Beam switch sensing component (102) acts as an interface between High Beam
Switch (144) of the vehicle and the microcontroller (100). As shown, the High Beam switch
22
sensing component (102) comprises a combination of resistors R31, R36 and R33 as a
voltage divider for converting the voltage of the high beam switch (144) to a digital
equivalent to a pre-defined value for the ADC pin of the microcontroller (100). R36 and R33
may have a resistance value of about 10 K while R31 may have a resistance value of about 20
K. The High Beam switch sensing component (102) further includes a Zener diode Z5 for
clamping the sensed switch voltage to the suitable voltage, such as about 5.1V, in order to
protect the ADC pin of the microcontroller. The High Beam switch sensing component (102)
also includes a capacitor C28 that is used as a filter and as a voltage stabilizer at the ADC pin
of the microcontroller 100. C28 may have a capacitance value of about 2.2nF and a workingvoltage of about 50 V. Moreover, the High Beam switch sensing component (102) may
include reverse voltage protection diode D5. The High Beam switch sensing component
(102) also comprises a resistor R192 which maintains the minimum operating current
requirement of the high beam switch (144). R192 may have a resistance value of about 562
Ohm.
Referring to Figure 5 there is illustrated an elaborate view of the Pass-beam Switch sensing
component (103) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The Pass-beam Switch sensing component (103), in accordance
with an embodiment of the invention, senses passing beam switch input voltage of the
vehicle. The Pass-beam Switch sensing component (103) acts as an interface between passing
beam Switch (145) of the vehicle and the microcontroller (100). As shown, the Pass-beam
Switch sensing component (103) comprises a combination of resistors R40, R43 and R41 as a
voltage divider for converting the voltage of the passingbeam switch (145) to a digital
equivalent to a pre-defined value for the ADC pin of the microcontroller (100). R43 and R41
may have a resistance value of about 10 K while R40 may have a resistance value of about 20
K. The Pass-beam Switch sensing component (103) further includes a Zener diode Z7 for
clamping the sensed switch voltage to the suitable voltage, such as about 5.1V, in order to
protect the ADC pin of the microcontroller. The Pass-beam Switch sensing component (103)
also includes a capacitor C31 that is used as a filter and as a voltage stabilizer at the ADC pin
of the microcontroller 100. C31 may have a capacitance value of about 2.2nF and a workingvoltage of about 50 V. Moreover, Pass-beam Switch sensing component (103) may include
reverse voltage protection diode D6. The Pass-beam Switch sensing component (103) also
comprises of a parallel combination of resistors R193 and R42 which maintains the minimum
23
operating current requirement of the passing switch 145. R193 and R42 each may have a
resistance value of about 562 Ohm.
Referring to Figure 6 there is illustrated an elaborate view of the Right Winker Switch
sensing component (104) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The Right Winker Switch sensing component (104), in
accordance with an embodiment of the invention, senses Right winker switch input voltage of
the vehicle. The Right Winker Switch sensing component (104) acts as an interface between
right winker Switch (146) of the vehicle and the microcontroller (100). As shown, the Right
Winker Switch sensing component (104) comprises a combination of resistors R52, R53 and
R55 as a voltage divider for converting the voltage of the Right winker switch (146) to a
digital equivalent to a pre-defined value for the ADC pin of the microcontroller (100). R55
and R53 may have a resistance value of about 10 K while R52 may have a resistance value of
about 20 K. The Right Winker Switch sensing component (104) further includes a Zener
diode Z9 for clamping the sensed switch voltage to the suitable voltage, such as about 5.1V,
in order to protect the ADC pin of the microcontroller. The Right Winker Switch sensing
component (104) also includes a capacitor C34 that is used as a filter and as a voltage
stabilizer at the ADC pin of the microcontroller (100). C34 may have a capacitance value of
about 2.2nF and a working-voltage of about 50 V. Moreover, the Right Winker Switch
sensing component (104) may include reverse voltage protection diode D8. The Right
Winker Switch sensing component (104) also comprises of a resistor R194 which maintains
the minimum operating current requirement of the Right winker switch 146. R194 may have
a resistance value of about 562 Ohm.
Referring to Figure 7 there is illustrated an elaborate view of the Left Winker Switch sensing
component (105) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The Left Winker Switch sensing component (105), in
accordance with an embodiment of the invention, senses Left winker switch input voltage of
the vehicle. The Left Winker Switch sensing component (105) acts as an interface between
Left winker Switch (147) of the vehicle and the microcontroller (100). As shown, the Left
Winker Switch sensing component (105) comprises a combination of resistors R57, R58 and
R60 as a voltage divider for converting the voltage of the left winker switch (147) to a digital
equivalent to a pre-defined value for the ADC pin of the microcontroller (100). R58 and R60
may have a resistance value of about 10 K while R57 may have a resistance value of about 20
24
K. The Left Winker Switch sensing component (105) further includes a Zener diode Z10 for
clamping the sensed switch voltage to the suitable voltage, such as about 5.1V, in order to
protect the ADC pin of the microcontroller. The Left Winker Switch sensing component
(105) also includes a capacitor C35 that is used as a filter and as a voltage stabilizer at the
ADC pin of the microcontroller 100. C35 may have a capacitance value of about 2.2nF and a
working-voltage of about 50 V. Moreover, the Left Winker Switch sensing component (105)
may include reverse voltage protection diode D9. The Left Winker Switch sensing
component (105) also comprises of a resistor R195 which maintains the minimum operating
current requirement of the left winker switch 147. R195 may have a resistance value of about
562 Ohm.
Referring to Figure 8 there is illustrated an elaborate view of the Brake / Sop Switch sensing
component (106) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The Brake / Stop Switch sensing component (106), in
accordance with an embodiment of the invention, senses Stop or Brake switch input voltage
of the vehicle. The Brake / Stop Switch sensing component (106) acts as an interface between
stop Switch (148) of the vehicle and the microcontroller (100). As shown, the Brake / Stop
Switch sensing component (106) comprises a combination of resistors R67, R68 and R70 as a
voltage divider for converting the voltage of the stop/brake switch (148) to a digital
equivalent to a pre-defined value for the ADC pin of the microcontroller (100). R68 and R70
may have a resistance value of about 10 K while R67 may have a resistance value of about 20
K. The Brake / Stop Switch sensing component (106) further includes a Zener diode Z12 for
clamping the sensed switch voltage to the suitable voltage, such as about 5.1V, in order to
protect the ADC pin of the microcontroller. The Brake / Stop Switch sensing component
(106) further includes a capacitor C37 that is used as a filter and as a voltage stabilizer at the
ADC pin of the microcontroller 100. C37 may have a capacitance value of about 2.2nF and a
working-voltage of about 50 V. Moreover, the Brake / Stop Switch sensing component (106)
may include reverse voltage protection diode D11. The Brake / Stop Switch sensing
component (106) also comprises of a parallel combination of resistors R197 and R69 which
maintains the minimum operating current requirement of the brake /stop switch 148. R197
and R69 each may have a resistance value of about 562 Ohm.
Referring to Figure 9 there is illustrated an elaborate view of the Hazard Switch sensing
component (107) forming part of the device (152) in accordance with an exemplary
25
embodiment of the invention. The Hazard Switch sensing component (107), in accordance
with an embodiment of the invention, senses Hazard switch input voltage of the vehicle. The
Hazard Switch sensing component (107) acts as an interface between Hazard Switch (149) of
the vehicle and the microcontroller (100). As shown, the Hazard Switch sensing component
(107) comprises a combination of resistors R62, R63 and R65 as a voltage divider for
converting the voltage of the hazard switch (149) to a digital equivalent to a pre-defined
value for the ADC pin of the microcontroller (100). R63 and R65 may have a resistance value
of about 10 K while R62 may have a resistance value of about 20 K. The Hazard Switch
sensing component (107) further includes a Zener diode Z11 for clamping the sensed switch
voltage to the suitable voltage, such as about 5.1V, in order to protect the ADC pin of the
microcontroller. The Hazard Switch sensing component (107) further includes a capacitor
C36 that is used as a filter and as a voltage stabilizer at the ADC pin of the microcontroller
100. C36 may have a capacitance value of about 2.2nF and a working voltage of about 50 V.
Moreover, the Hazard Switch sensing component (107) may include reverse voltage
protection diode D10. The Hazard Switch sensing component (107) also comprises of a
parallel combination of resistors R196 and R64 which maintains the minimum operating
current requirement of the passing switch 149. R196 and R64 each may have a resistance
value of about 562 Ohm.
Now referring to Figure 10 there is illustrated an elaborate view of the engine parameter
sensing component (108) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The engine parameter sensing component (108), in accordance
with an embodiment of the invention, senses engine status signal from an engine status
providing unit (110) of the vehicle. The engine parameter sensing component (108) acts as an
interface between engine status providing unit (110) and the microcontroller (100). As
shown, the engine parameter sensing component (108) comprises a combination of resistors
R34, R37 and R38 as a voltage divider for translating engine status signal from control unit
(110) to a digital equivalent to a pre-defined value for the ADC / Interrupt pin of the
microcontroller (100). R37 and R38 may have a resistance value of about 4.7 K while R34
may have a resistance value of about 10 K. The engine parameter sensing component (108)
further includes a Zener diode Z6 for clamping the sensed voltage to the suitable voltage,
such as about 5.1V, in order to protect the ADC / Interrupt pin of the microcontroller. The
engine parameter sensing component (108) also includes a capacitor C30 that is used as a
filter and as a voltage stabilizer at the ADC / Interrupt pin of the microcontroller (100). C30
26
may have a capacitance value of about 2.2nF and a working voltage of about 50 V. The
engine parameter sensing component (108) may include capacitor C29 (may have
capacitance of about 15nF with working voltage of about 50V) to filter noise at engine status
signal of the vehicle. Moreover, the engine parameter sensing component (108) may include
a diode D34 or resistance R289 for reverse voltage protection depending on customer
requirement. The engine parameter sensing component (108) is pulled up through built in
regulated power supply (113).
Now referring to Figure 11 there is illustrated an elaborate view of the regulated power
supply component (113) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The regulated power supply component (113) provides
regulated supply, such as about 5V constant voltage, to various elements forming part of the
device (152). The regulated power supply component 113 receives as an input from input
voltage protection circuit (101). As shown, the regulated power supply component 113
includes a voltage regulator IC U2 having in-built load dump protection and may be selected
as to provide 5V for min. 6V input battery voltage. A first capacitor C19, with capacitance
value of about 100nF and working voltage of about 50V, may be used to filter noise at output
of regulated supply. A polarized capacitor C17 with a capacitance value of about 22uF and
working voltage of about 6.3 V may be used as a voltage stabilizer at the output terminal of
the voltage regulator (U2). The regulated power supply component 113 further includes a
capacitor C18 for filtering noise signal at the input of the voltage regulator (U2). C18 may
have the capacitance of about 47nF and may be associated with a working voltage of about
50V. The regulated supply component 113 may include a resistor R18 for discharging the
polarised capacitor (C17) when there is no voltage at the input terminal of the voltage
regulator U2. R18 may have the resistance value of about 47K. The regulated supply
component 113 may include a diode D13, which acts as a switching diode, to provide path for
reverse current which protects the voltage regulator (U2) from damage.
Now referring to Figure 12 there is illustrated an elaborate view of the microcontroller (100)
and its peripheral circuit forming part of the device (152) in accordance with an exemplary
embodiment of the invention. In an implementation, the microcontroller 100 is a 16-bit
microcontroller that performs the automatic switching functionality of all LED loads in a
vehicle by sensing some input parameters i.e. 109-110 and 144-149, detecting open and short
fault in LEDs and thus driving and controlling all LEDs (150-151and 134-138) depending on
27
sensed input parameters. In an example, depending upon the engine status signal head lamp is
switched ON and OFF. In other words, apart from turning on head lamp, the microcontroller
100 also switches between high beam and low beam LEDs, controls blinking frequency of
winker LEDs, detects open and short fault condition of a LED, senses various input switches
present in the vehicle and controls cluster LED indicators. Microcontroller (100) is also
responsible for generating delays in switching and defining time intervals required for fault
detection and error proofing.
In an implementation, all unused pins of the microcontroller 100 may be configured as output
low. Further, the status of the High beam input switch 144, the passing beam input switch
145, the right winker input switch 146, the left winker input switch 147, the brake/stop input
switch 148, and the hazard input switch 149, the voltage of the battery 109, the status of the
engine 110, the LED short fault in head lamp 150-151 and open LED fault in all four winker
LEDs 134-137 is sensed by the ADC pins of the microcontroller 100. Furthermore, left-front
winker LED short fault 125, right-front winker LED short fault 126, left-rear winker LED
short fault 127and right-rear winker LED short fault signal 128 is sensed as an interrupt by
the microcontroller 100. In addition to that, a cluster indicator control signal for High beam
LEDs 141, a cluster indicator control signal for left winker LEDs 140, a cluster indicator
control signal for right winker LEDs 139, a control signal for switching low beam LEDs 151
and high beam LEDs150, a control signal for left-front winker LED 134, a control signal for
right-front winker LED 135, a control signal for left-rear winker LED 136, a control signal
for right-rear winker LED 137, a control signal for stop and tail LEDs 138, control signal for
position LED 133 and switch illumination LEDs 132 is also given by microcontroller
depending upon sensed input parameters. As shown, a combination of a diode D12, a resistor
R181 (may have resistance value of about 4.7K) and a capacitor C66 (may have a capacitance
value of about 100nF with working voltage of about 50V) may be used for a RESET pin of
the microcontroller (100). Further, a second capacitor C67 may be used as a filter for internal
regulation of the microcontroller (100). C67 may have the capacitance of about 470nF with a
working voltage of about 50V. A third capacitor C65 may be used as a filter for noise signals
and as a voltage stabilizer at an input supply pin of the microcontroller (100). C24 may have
the capacitance of about 1uFwith working voltage of about 25V. Further, unused external
crystal pins are pulled up with regulated power supply (113) using resistance R182 and R183
(each may have resistance value of about 10K). Further, a connector J2 is used for
programming the microcontroller (100).
28
Now referring to Figure 13 there is illustrated an elaborate view of the High-beam LED
Lamp driver component (114) forming part of the device (152) in accordance with an
exemplary embodiment of the invention.
The High-beam LED Lamp driver component (114) uses H-bridge (Buck-boost) topology to
supply constant current to head lamp LEDs of the vehicle i.e. 150-High beam and 151-low
beam. As shown, the High-beam LED Lamp driver component (114) uses a power inductor
L5 and a high side switching MOSFET Q23 and a low side switching MOSFET Q3. The
High-beam LED Lamp driver component (114) uses a buck-boost controller IC U10 which
may have individual high and low side switch controls, adjustable regulating frequency, an
in-built frequency dithering, under voltage lockout (UVLO) feature and output current and
voltage control feedbacks. Switching MOSFETs Q3 and Q23 are controlled by the controller
IC U10, through resistors R19, R218, R219 and R224. Resistors R19, R218, R219 and R224
may have resistance value of about 15 ohm. A bulk capacitor C103 is used to supply ripple
less and stable input supply voltage to U10 IC through input protection circuit (101) in case
of battery less condition. Capacitor C103 may have capacitance value of about 220uF with
working voltage of about 35V. Another set of capacitors C110 and C115 (may have value of
about 1uF with working voltage of about 50V) is used to filter out noise in input supply line
and input sense pin of U10 IC. A diode D24 or resistor R281 (with resistance value of about
2K) is used for sensing input supply by U10 IC. U10 IC’s mode of operation can be
configured through a resistor R225 having a resistance value of about 93.1 K. Furthermore,
using a resistor R226 with a resistance value of about 75K, regulating frequency for the
controller IC U10 can be configured. U10 IC may have configurable frequency dithering
feature with the use of parallel capacitors C118 and C161. Capacitor C118 may have
capacitance value of 1uF with working voltage of about 25V while capacitor C161 may have
a capacitance value of about 470nF with working voltage of about 50V.
Moreover, soft start timing for the U10 controller is defined using capacitor C116
(capacitance value of about 120nF and working voltage of about 50V). Further, for stable
DC-DC regulation U10 may have different compensation techniques like slope compensation
is done by adding capacitor C120 (with capacitance value of about 390pF or about 1nF and
working voltage of about 50V) and error amplifier compensation which comprises
combination of resistor R24 (with resistance value of about 15K) in series with a capacitor
29
C121 (with capacitance value of about 68nF and working voltage about 50V) in parallel with
another capacitor C119 (with capacitance value of about 390pF and working voltage of about
50V). Output load voltage feedback is provided to U10 IC through a resistor divider
combination of R25 and R35. Resistor R25 may have a resistance value of about 2K while
R35 may have a resistance value of about 43K. Constant output current is maintained through
a current sensing feedback, which comprises of resistor R233, R234 and a capacitor C122 to
filter noise, and a current setting resistors R215. Resistor R233 and R234 each may have
resistance value of about 100 ohm while resistance R215 may have value of about 56 milliohm. Capacitor C122 may have a value of about 1uF with working voltage of about 25V. To
prevent saturation of power inductor (L5) through over current flow, another current control
feedback is provided through resistor R228 and R30 (may have resistance value of about 100
ohm) and current limiting resistor R229 (may have value of about 33 or about 11 milli-ohm).
Further, constant output current is achieved by using two bulk polarised capacitors C148 and
C170 (each may have a capacitance value of about 220uF with working voltage of about
35V). A parallel combination of capacitors (C104, C105, C106, C108, C162, C165 and
C117) are used to filter noise and minimise current ripples at output LEDs. Capacitors C104,
C105, C106, and C162 may have a capacitance value of about 2.2uF with working voltage of
about 25V while C108 may have a capacitance value of about 100nF and C165 may have a
capacitance value of about 10nF both with working voltage of about 50V. Moreover, a Diode
D26 is used to protect MOSFETs from short to battery/ground condition. For efficient
switching of high side MOSFET, U10 IC also uses combination of a diode D14 or D7 with
R215 or R252 (with resistance value of about 10 ohm) and capacitor C111 or C112 (with
capacitance value of about 100nF and working voltage of about 50V). Internal regulated
supply of U10 IC is filtered against noise through capacitor C113 (may have a capacitance
value of about 2.2uF with working voltage of about 25V). U10 IC is enabled and disabled
after certain battery voltage is achieved using resistor divider combination R264 (may have
resistance value of about 158K), R263 (may have resistance value of about 36K) and R267
(may have resistance value of about 3K) grounded through transistor Q27 which is turned
through an resistor divider circuit R217 and R262 (both may have a resistance value of about
10K) by microcontroller (100) using sensing circuits (108 and 112). Capacitor C109 and
C174 is used to filter noise at Q27 transistor terminals. A diode D21 is used to protect U10 IC
from reverse voltage. Another resistor R227 (with resistance value of about 10K) is used for
internal operation of the U10 IC.
30
Now referring to Figure 14 there is illustrated an elaborate view of the head lamp fault
detection component (115) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The head lamp fault detection component (115) senses Head
lamp LED voltage of the vehicle, and acts as an interface between headlamp LEDs (150-151)
of the vehicle and the microcontroller (100). Reading this load voltage, microcontroller (100)
takes decision whether to switch On Head lamp or not. As shown, the head lamp fault
detection component (115) comprises a combination of resistors R8, R10 and R15 as a
voltage divider for converting the voltage of the Headlamp LEDs to a digital equivalent to a
pre-defined value for the ADC pin of the microcontroller 100. R8 and R10 may have a
resistance value of about 30 K while R15 may have a resistance value of about 15 K. The
head lamp fault detection component (115) further includes a Zener diode Z2 for clamping
the sensed LED voltage to the suitable voltage, such as about 5.1V, in order to protect the
ADC pin of the microcontroller. The head lamp fault detection component (115) also
includes a capacitor C12 that is used as a filter and as a voltage stabilizer at the ADC pin of
the microcontroller 100. C12 may have a capacitance value of about 10nF with working
voltage of about 50 V.
Now referring to Figure 15 there is illustrated an elaborate view of the Low-beam LED lamp
driver component (116) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The Low-beam LED lamp driver component (116) switches the
low beam LEDs (151) and high beam LEDs (150) of the vehicle. Low beam LEDs 151 is
derived through head lamp driver circuit 114. As shown, the Low-beam LED lamp driver
component (116) mainly comprises of MOSFET Q2 which is turned on using resistor divider
R189 (with resistance value of about 12K) and R21 (with resistance value of about 4.7K)
ground through another transistor Q17. Q17 transistor is switched on by microcontroller 100
depending upon sensed input parameters through circuits 102, 103 and 108. Gate to Source
terminals of MOSFET is protected against application of over-voltage using Zener Z18 which
may have clamping voltage of about 8.2V. Signal from microcontroller (100) to turn on Q17
transistor is transmitted through resistor divider R190 and R190, each may have resistance
value of about 10K. A capacitor C72 is used to filter noise at Q17 transistor. Another
capacitor C93 is used at output of low beam LEDs 151 to filter noise. Capacitor C72 and C93
both may have capacitance value of about 10nF with working voltage of about 50V. The
Low-beam LED lamp driver component (116) also includes an additional combination of a
resistor R188 (with value about 4.7 Ohm) and two parallel capacitorsC71 (with capacitance
31
value of about 470nF and working voltage of about 50V) and C173 (with capacitance value
of about 330nF and working voltage of about 50V), to increase the switching time of
MOSFET Q2 during switching of high beam and low beam LEDs 150 and 151 respectively.
Further, the Low-beam LED lamp driver component (116) consists a Diode D25 from short
to battery/ground protection. The Low-beam LED lamp driver component (116) also
comprises forceful switching off for MOSFET Q2 in case of make and break condition of
headlamp LED as per customer requirement. During make and break condition voltage of the
LED rises which is translated into turning on transistor Q28, through series combination of
resistors R276 (with resistance value of about 10K), R271 (with resistance value of about
10K), R274 (with resistance value of about 24K) & R275 (with resistance value of about
10K) and a Zener diode Z23 (to turn ON Q28 Transistor above certain voltage), which in turn
turns ON transistor Q29. Another series resistors R278 and R279 (both may have resistance
value of about 4.7K) is used to bias Q29 transistor. Capacitor C176 and C177 (both may have
capacitance value of about 10nF with working voltage of about 50V) are used to filter noise
at terminals of transistor Q28 and Q29 respectively.
Now referring to Figure 16 there is illustrated an elaborate view of the Buck converter
component (117) forming part of the device (152) in accordance with an exemplary
embodiment of the invention. The Buck converter component (117) drives the driver
components except for the High-beam LED Lamp driver component (114); the Low-beam
LED lamp driver component (116); the Right Winker Cluster indicator lamp driver
component (129); the Left Winker Cluster indicator lamp driver component (130); and the
High beam cluster indicator lamp driver component (131).
Thus, Buck converter component (117) drives the Switch Illumination LED lamp driver
component (118); the Position indicating LED lamp driver component (119); the Left-front
LED Winker lamp driver component (120); the Right-front LED Winker lamp driver
component (121); the Left-rear LED Winker lamp driver component (122); the Right-rear
LED Winker lamp driver component (123); and the Stop/Tail LED lamp driver component
(124).
The Buck converter component (117) uses Buck topology to step down switching voltage
regulator of vehicle’s battery 109 into regulated power supply, say approximately 9V,
required by linear current drivers to manage power dissipation according to LED load voltage
32
at its output side for constant current operation for respective LED. As shown, the Buck
converter component (117) comprises of a step-down switching voltage regulator IC U3
having inbuilt switching MOSFET, adjustable regulating frequency, frequency dithering and
under-voltage lockout (UVLO) features and may be selected to provide approx. regulated 9V
supply for min. 10.5 V battery input voltage. A power inductor L4 (may have value of about
22uH) with a bulk capacitor C23 is used for buck mode operation and to stabilize approx. 9V
supply. C23 may have capacitance value of about 220uF and working voltage of about 35V.
A diode D4 is also used as per buck topology (for free-wheeling diode) requirements.
Capacitor C21 and C24 are used at both input and output sides of U3 IC for filtering out noise
in the input and output signals, respectively. C21 may have a capacitance value of about
4.7uF and C24 may have a capacitance value of about 470nF, while both capacitors may have
working voltage of about 50V. A second capacitor C22 with capacitance value of about
100nF and working voltage of about 50V is used to filter out frequency noise in input supply.
Regulating frequency of the switching MOSFET of U3 IC can be selected using a resistor
R26 having a resistance value of about 110 K for frequency suitable according to EMI/EMC
noise filtering requirements. The Buck converter component (117) also needs capacitor C25
for soft start function. C25 may have a value of about 2.2nF with working voltage of about
50V. A combination of resistance R213 (with a resistance value of about 4.7 ohm) and
capacitor C20 (with capacitance value of about 100nF with working voltage of 50V) is used
to charge pump of internal MOSFET in buck regulation topology. Output regulated voltage
of U3 IC is maintained using resistor based feedback circuit, comprising resistors R23 and
R27. R23 may have resistance value of about 127 K while R27 may have a resistance value
of about 11.3 K for regulated supply of about 9V. The Buck converter component (117) also
comprises of combination of resistor R259 (say about 210K), R260 (say about 30K) and
R268 (say about 3K) which enables U3 IC to switch operation On/Off after certain input
voltage is applied. A capacitor C175 is used to filter noise at enable signal of U3 IC. C175
may have value of about 2.2nF with working voltage of about 50V.
Now referring to Figure 17 there is illustrated a driver component which acts as the Leftfront LED Winker lamp driver component (120); the Right-front LED Winker lamp driver
component (121); the Left-rear LED Winker lamp driver component (122); and the Rightrear LED Winker lamp driver component (123) forming part of the device (152) in
accordance with an exemplary embodiment of the invention. The driver component shown in
Figure 17 uses a linear constant current driver IC U4 which is driven through regulated power
33
supply generated by the Buck converter component (117). U4 IC drives each individual
winker LED (134-137) through four independent driver components (120-123), which have
independent current and switching control. The driver component shown in Figure 17 has a
capacitor C39 at input to filter noise in input supply line. C39 may have capacitance value of
about 100nF with working voltage of about 50V.U4 IC may provide the open LED fault
signal to microcontroller (100) through combination of Resistors R269 and R76 and capacitor
C83 and C84 to filter noise at microcontroller pin. Resistors R269 and R76 may have value
of about 10K while capacitors C83 and C84 may have value of about 10nF with working
voltage of about 50V.
By way of example, the Left-front LED Winker lamp driver component (120) of U4 IC may
use a resistor R85 (with resistance value of about 11.5K) for setting constant current through
left front winker LED (134). Blinking of Left front winker LED is controlled through
transistor Q5 which additionally gets signal from microcontroller 100 taking decision based
on some sensed input signal.
By way of another example, the Right-front LED Winker lamp driver component (121) of U4
IC may use a resistor R94 (with resistance value of about 11.5K) for setting constant current
through right front winker LED (135). Blinking of right front winker LED is controlled
through transistor Q6 which additionally gets signal from microcontroller 100 taking decision
based on some sensed input signal.
Similarly, the Left-rear LED Winker lamp driver component (122) of U4 IC may use a
resistor R88 (with resistance value of about 11.5K) for setting constant current through left
rear winker LED (136). Blinking of Left rear winker LED is controlled through transistor Q7
which additionally gets signal from microcontroller 100 taking decision based on some
sensed input signal.
Last, but not the least, the Right-rear LED Winker lamp driver component (123) of U4 IC
may use a resistor R101 (with resistance value of about 11.5K) for setting constant current
through right rear winker LED (137). Blinking of right rear winker LED is controlled through
transistor Q8 which additionally gets signal from microcontroller 100 taking decision based
on some sensed input signal.
34
The output side of U4 IC may be comprised of parallel combination of capacitors C150,
C151, C86, C89, C166, C167, C168, and C169 for each individual output to filter out noise at
output LEDs. Capacitors C150, C151, C86 and C89 may have capacitance value of about
470nf while capacitors C166, C167, C168 and C169 may have capacitance value of about
1nF with working voltage of about 50V. Further, each individual output of the U4 may have a
resistance R282 (likewise R283, R284 and R285) or a diode D30 (likewise D31, D32, and
D35) for reverse voltage protection according to customer requirements.
Now referring to Figure 18 there is illustrated an elaborate view of the left font winker LED
short detection component (125); the right front winker LED short detection component
(126); the left rear winker LED short detection component (127); and the right rear winker
LED short detection component (128) in accordance with an exemplary embodiment of the
invention. Each of the short detection component acts as an interface between the winker
LEDs (134-137), and the microcontroller (100).
The left font winker LED short detection component (125) used for Left front winker LED
comprises of a comparator IC (U5a) which is derived through regulated power supply
component 113 with input supply line noise filtering capacitor C46 (with capacitance value
of about 10nF with working voltage of about 50V), a first resistor divider combination R84
(with a resistance value of about 23.2K) and R87 (with a resistance value of about 27K)
pulled up by regulated supply circuit 113 for negative reference of the comparator and a
second resistor divider combination R80 and R86 (both may have a resistance value of about
30K) translating voltage of Left front winker LED for positive reference of the comparator.
In LED short condition voltage will decrease, which will make the output of the comparator
permanently low. The signal from comparator is monitored by interrupt on microcontroller
(100) through a resistor R83 (with a resistance value of about 10K) and noise filter capacitor
C40 (with a capacitance value of about 10nF and working voltage of about 50V).
The right front winker LED short detection component (126) used for right front winker LED
comprises of a comparator IC (U5b), a first resistor divider combination R96 (with a
resistance value of about 23.2K) and R100 (with a resistance value of about 27K) pulled up
by regulated supply circuit 113 for negative reference of the comparator and a second resistor
divider combination R92 and R99 (both may have a resistance value of about 30K)
translating voltage of right front winker LED for positive reference of the comparator. In
35
LED short condition voltage will decrease, which will make the output of the comparator
permanently low. The signal from comparator is monitored by interrupt on microcontroller
(100) through a resistor R95 (with a resistance value of about 10K) and noise filter capacitor
C42 (with a capacitance value of about 10nF and working voltage of about 50V).
The left rear winker LED short detection component (127) used for left rear winker LED
comprises of a comparator IC (U5c), a first resistor divider combination R117 (with a
resistance value of about 23.2K) and R120 (with a resistance value of about 27K) pulled up
by regulated supply circuit 113 for negative reference of the comparator and a second resistor
divider combination R113 and R119 (both may have a resistance value of about 30K)
translating voltage of left rear winker LED for positive reference of the comparator. In LED
short condition voltage will decrease, which will make the output of the comparator
permanently low. The signal from comparator is monitored by interrupt on microcontroller
(100) through a resistor R116 (with a resistance value of about 10K) and noise filter capacitor
C47 (with a capacitance value of about 10nF and working voltage of about 50V).
The right rear winker LED short detection component (128) used for right rear winker LED
comprises of a comparator IC (U5d), a first resistor divider combination R130 (with a
resistance value of about 23.2K) and R132 (with a resistance value of about 27K) pulled up
by regulated supply circuit 113 for negative reference of the comparator and a second resistor
divider combination R127 and R131 (both may have a resistance value of about 30K)
translating voltage of right rear winker LED for positive reference of the comparator. In LED
short condition voltage will decrease, which will make the output of the comparator
permanently low. The signal from comparator is monitored by interrupt on microcontroller
(100) through a resistor R128 (with a resistance value of about 10K) and noise filter capacitor
C49 (with a capacitance value of about 10nF and working voltage of about 50V).
Now referring to Figure 19 there is illustrated an elaborate view of the Stop (Brake) / Tail
LED lamp driver component (124) forming part of the device (152) in accordance with an
exemplary embodiment of the invention. The Stop (Brake) / Tail LED lamp driver
component (124) drives the Stop (Brake) / Tail LEDs (138) of the vehicle. As shown, the
Stop (Brake) / Tail LED lamp driver component (124) uses a linear constant current driver IC
U7 which is driven by regulated power supply generated by the Buck converter component
(117). The Stop (Brake) / Tail LED lamp driver component (124) controls switching between
tail mode and stop/brake mode. The Stop (Brake) / Tail LED lamp driver component (124),
36
has a capacitor C52 at input to filter noise in input supply line. C52 may have a capacitance
value of about 100nF with working voltage of about 50V. U7 IC may have feature of
providing constant current to LED with the help of a resistor R150 (with a resistance value of
about 36K) for tail mode current and combination of resistors R151, R152 and R153 (all may
have resistance value of about 24K) for stop mode current. Switching of tail and Stop (Brake)
mode is controlled through individual transistors Q11 and Q24, which additionally gets signal
from microcontroller (100) taking decision based on some sensed input signals from the Stop
(Brake) Switch sensing component (106). For tail mode operation, Q11 is turned on by
microcontroller (100) and for Stop (Brake) mode operation Q11 and Q24 both are turned on
to create combination of current required. The circuit 124 may have in-built feature to detect
open load condition at output which may be read by microcontroller (100) through a
combination of resistor R141 and a capacitor C80, as per customer requirement and an
another combination of a resistor R143 and a capacitor C95 and filter noise at microcontroller
pin. R141 and R143 may have resistance value of 10K and C80 and C95 may have
capacitance value of about 10nF with working voltage of about 50V. The output side of U7
IC may comprised of parallel combination of capacitors C54 and C55 to filter out noise to
output LEDs. Capacitor C54 may have a capacitance value of about 10nF while C55 may
have a capacitance value of about 470nF with working voltage of about 50V. Further, output
of the U7 may have a resistance R286 or a diode D27 for reverse voltage protection
according to customer requirements.
Now referring to Figure 20 there is illustrated an elaborate view of the Switch Illumination
LED lamp driver component (118); and Position indicating LED lamp driver component
(119) forming part of the device (152) in accordance with an exemplary embodiment of the
invention. The Switch Illumination LED lamp driver component (118) and Position
indicating LED lamp driver component (119) are shown to share certain components. In
particular, the Switch Illumination LED lamp driver component (118) and Position indicating
LED lamp driver component (119) together comprise a linear constant current driver IC U8
which is driven by regulated power supply generated by the Buck converter component
(117). There is provided a capacitor C62 which acts to filter noise in input supply line. C62
may have value of about 100nF with working voltage of about 50V. The Position indicating
LED lamp driver component (119) of U8 IC may use a combination of resistors R177 and
R178 (with resistance value of about 24K) for setting constant current through position LED
(133). Switching of Position LED is controlled through transistor Q19 which additionally
37
gets signal from microcontroller (100) taking decision based on some sensed input signal.
The Switch Illumination LED lamp driver component (118) of U8 IC may use a combination
of resistors R179 and R180 (with resistance value of about 36K) for setting constant current
through switch illumination LED (132). Switching of switch illumination LED is controlled
through transistor Q25 which additionally gets signal from microcontroller (100) taking
decision based on some sensed input signal. The Switch Illumination LED lamp driver
component (118) and Position indicating LED lamp driver component (119) together may
have in-built feature to detect open load condition at output which may be read by
microcontroller (100) through combination of a resistor R171 and a capacitor C81 and
another combination of a resistor R173 and a capacitor C96 to filter noise at microcontroller
pin. R171 and R173 may have value of about 10K and C81 and C96 may have value of about
10nF with working voltage of about 50V. The output of U8 IC may comprise of a parallel
combination of capacitors C64 and C172 (with capacitance value of about 470nF and about
1nF with working voltage of about 50V respectively) to filter out noise to position LEDs and
an another parallel combination of capacitors C97 and C171 or R280 (with capacitance value
of about 470nF and about 1nF with working voltage of about 50V respectively) to filter out
noise to switch illumination LEDs. Further, output of the U8 may have a resistance R287
(likewise R288) or a diode D28 (likewise D29) for reverse voltage protection as per customer
requirements. Moreover, to manage power dissipation because of low potential of switch
illumination LED, a Zener diode Z19 may be used having clamping voltage of about 3.3V.
Now referring to Figure 21 there is illustrated an elaborate view of the Right Winker Cluster
indicator lamp driver component (129) forming part of the device (152) in accordance with
an exemplary embodiment of the invention. In an embodiment of the invention, the Right
Winker Cluster indicator lamp driver component (129) comprises of a low side drive
configuration for indication LED. In particular, Transistor Q9 is turned on by the
microcontroller (100) depending upon output of the Right Winker Switch sensing component
(104). The Right Winker Cluster indicator lamp driver component (129) furthermore
comprises of resistor divider R136 and R140 to turn on the transistor Q9. R136 and R140
may have a resistance value of about 10K. Moreover, a capacitor C53 is used for filter noise
at Q9 transistor. C53 may have a capacitance value of about 10nF with working voltage of
about 50V. Further, the Right Winker Cluster indicator lamp driver component (129) also
comprises of resistance R135 (with the resistance value of about 430 ohm) to protect
transistor Q9 from getting damaged due to over current flow. A secondary capacitor C98
38
(with capacitance value of about 10nF and working voltage of about 50V) is used for filtering
noise at right winker cluster indicator LED.
Now referring to Figure 22 there is illustrated an elaborate view of the Left Winker Cluster
indicator lamp driver component (130) forming part of the device (152) in accordance with
an exemplary embodiment of the invention. In an embodiment of the invention, the Left
Winker Cluster indicator lamp driver component (130) comprises of a low side drive
configuration for indication LED. In particular, Transistor Q10 is turned on by the
microcontroller (100) depending upon output of the Left Winker Switch sensing component
(105). The Left Winker Cluster indicator lamp driver component (130) comprises of resistor
divider R147 and R149 to turn on the transistor Q9. R147 and R149 may have a resistance
value of about 10K. Moreover, a capacitor C56 is used for filter noise at Q10 transistor. C56
may have a capacitance value of about 10nF with working voltage of about 50V. Further, the
Left Winker Cluster indicator lamp driver component (130) also comprises of resistance
R144 (with the resistance value of about 430 ohm) to protect transistor Q10 from getting
damaged due to over current flow. A secondary capacitor C91 (with capacitance value of
about 10nF and working voltage of about 50V) is used for filtering noise at left winker cluster
indicator LED.
Now referring to Figure 23 there is an elaborate view of the High beam cluster indicator
lamp driver component (131) forming part of the device (152) in accordance with an
exemplary embodiment of the invention. In an embodiment of the invention, the High beam
cluster indicator lamp driver component (131) comprises of a low side drive configuration for
indication LED. In particular, Transistor Q12 is turned on by the microcontroller (100)
depending upon outputs from the High-Beam Switch sensing component (102), the Passbeam Switch sensing component (103), and the engine parameter sensing component (108).
The High beam cluster indicator lamp driver component (131) comprises of resistor divider
R157 and R159 to turn on the transistor Q12. R157 and R159 may have a resistance value of
about 10K. Moreover, a capacitor C58 is used for filter noise at Q12 transistor. C58 may have
a capacitance value of about 10nF with working voltage of about 50V. Further, the High
beam cluster indicator lamp driver component (131) also comprises of resistance R154 (with
a resistance value of about 430 ohm) to protect transistor Q12 from getting damaged due to
over current flow. A secondary capacitor C92 (with a capacitance value of about 10nF and
working voltage of about 50V) is used for filtering noise at high beam cluster indicator LED.
39
At least by virtue of aforesaid embodiments, the present subject matter describes a multifunctional device 152 that leads to a substantial control over automatic switching the
vehicle’s LED lighting operation while the vehicle is being driven based on various sensed
parameters. Such discreet functionalities as exhibited by the device 152 leads to substantial
cost conservation minimizing the number of individual LED drivers to be used for vehicle
lighting.
Moreover, the device 152 incorporates a simpler arrangement of electronic/electrical
components, thereby being durable and easily instantiable within the vehicle’s chassis.
Moreover, owing to being multi-functional in nature, the device 152 proves cost-efficient in
the long run.
While certain present preferred embodiments of the invention have been illustrated and
described herein, it is to be understood that the invention is not limited thereto, but may be
otherwise variously embodied and practiced within the scope of the following claims.

WE CLAIM:

1. A device (152) for illuminating one or more LED-based vehicular lamps (150, 151,
132-141) forming part of a vehicle, the device (152) forming part of a circuit
comprising a power source; plurality of LED-based vehicular lamps (150, 151, 132-
141); and plurality of switches (144-149) for controlling illumination state of a LEDbased vehicular lamp corresponding thereto, the device (152) comprising:
an input voltage sensing component (112) for sensing an amount of input
voltage and generating an input voltage indicating signal corresponding thereto;
an engine parameter sensing component (108) for sensing a parameter
pertaining to an engine of the vehicle and generating an engine parameter indicating
signal corresponding thereto;
plurality of switch sensing components (102-107) for sensing status of each of
the plurality of switches (144-149) and generating switch state indicating signals
corresponding thereto;
plurality of fault detection components (115, 125-128) for sensing fault in the
LED-based vehicular lamps (150, 151, 134-137) and generating fault indicating
signals corresponding thereto;
a microcontroller (100) adapted to receive the input voltage indicating signal,
the engine parameter indicating signal, the switch state indicating signals, and the
fault indicating signals and based thereupon generate one or more LED lamp control
signals; and
plurality of driver components (114, 116-124, 129-131) adapted to receive the
LED lamp control signal from the microcontroller and cause illumination of the LEDbased vehicular lamp (150, 151, 132-141) connected thereto.
2. The device as claimed in claim 1, wherein:
(a) the one or more LED-based vehicular lamps (150, 151, 132-141) include:
• LED-based High-beam lamp (150);
• LED-based Low-beam lamp (151);
• LED-based Switch Illumination lamp (132);
• LED-based Position indicating lamp (133);
• LED-based Left-front Winker lamp (134);
• LED-based Right-front Winker lamp (135);
41
• LED-based Left-rear Winker lamp (136);
• LED-based Right-rear Winker lamp (137);
• LED-based Stop (Brake) / Tail lamp (138);
• LED-based Right Winker Cluster indicator lamp (139);
• LED-based Left Winker Cluster indicator lamp (140); and
• LED-based high beam cluster indicator lamp (141);
(b) the one or more switches (144-149) include:
• a High-Beam / Low Beam Switch (144);
• a Pass-beam Switch (145);
• a Right Winker Switch (146);
• a Left Winker Switch (147);
• a Brake / Stop witch (148); and
• a Hazard Switch (149);
(c) the switch sensing components (102-107) include:
• a High-Beam / Low-Beam Switch sensing component (102);
• a Pass-beam Switch sensing component (103);
• a Right Winker Switch sensing component (104);
• a Left Winker Switch sensing component (105);
• a Stop / Brake Switch sensing component (106); and
• a Hazard Switch sensing component (107);
(d) the power source includes:
• a battery (109); and
• a combination comprising an alternating current (AC) generator (143) and
an AC-DC converter (142);
(e) the fault detection components (115, 125-128) include:
• head lamp fault detection component (115);
• left font winker LED short detection component (125);
• right front winker LED short detection component (126);
• left rear winker LED short detection component (127); and
• right rear winker LED short detection component (128); and
(f) the driver components (114, 116-124, 129-131) include:
• High-beam LED Lamp driver component (114);
42
• Low-beam LED lamp driver component (116);
• A Buck converter component (117);
• Switch Illumination LED lamp driver component (118);
• Position indicating LED lamp driver component (119);
• Left-front LED Winker lamp driver component (120);
• Right-front LED Winker lamp driver component (121);
• Left-rear LED Winker lamp driver component (122);
• Right-rear LED Winker lamp driver component (123);
• Stop (Brake) / Tail LED lamp driver component (124);
• Right Winker Cluster indicator lamp driver component (129);
• Left Winker Cluster indicator lamp driver component (130); and
• High beam cluster indicator lamp driver component (131).
3. The device as claimed in claim 1, further comprising:
• an input voltage protection component (101) for protecting the device (152) from
damage in case of reverse battery voltage and transient pulses; and
• a regulated power supply component (113) for operating the microcontroller (100)
and other components.
4. The device as claimed in claim 3, wherein the Input Voltage protection component
(101) comprises a MOSFET (Q14), a combination of resistors (R235 & R236) for
turning on the MOSFET, a Diode (D20) and Zener diode (Z22) to protect MOSFET
(Q14) from reverse and over-voltage, a polarised bulk Capacitor (C127) for providing
stable input voltage in battery-less condition, a combination of capacitors (C128,
C130 and C164) and a power inductor (L6) for minimizing EMI/EMC noise, and a
Transient voltage suppressor diode (D23) for suppressing transient pulses that may be
generated in vehicle.
5. The device as claimed in claim 3, wherein the regulated power supply component
(113) is configured to provide a 5V signal to the microcontroller (100) and other
components, and wherein the regulated power supply component (113) comprises a
voltage regulator IC (U2) having load dump protection, a first capacitor (C18) as a
voltage stabilizer at input terminal of the voltage regulator (U2), a second capacitor
(C17) adapted to filter and stabilize voltage at the output terminal of the voltage
43
regulator (U2), a third capacitor (C19) for filtering noise at the output terminal of the
voltage regulator (U2), a resistor (R18) for discharging the second and third
capacitors (C17 and C19) when there is no voltage at the input terminal of the voltage
regulator IC (U2), and a diode (D13) to provide path for reverse current which
protects the voltage regulator (U2) from damage.
6. The device as claimed in claim 1, wherein each of the plurality of driver components
(114, 116-124, 129-131) is based on MOSFETs & Transistors (Q2, Q3, Q23, Q27,
Q5, Q6, Q7, Q8, Q9, Q10, Q11, Q12, Q17 Q19, Q24, Q25, Q28 and Q29 ), inductors
(L5 and L4), and driving ICs (U3, U4, U5, U7, U8 and U10).
7. The device as claimed in claim 1, wherein the power source is connected to the device
(152) via a DC line.
8. The device as claimed in claim 7, wherein the High-Beam / Low-Beam switch (144),
the Passing beam input switch (145), the Right winker input switch (146), the Left
winker input switch (147), the Brake/Stop input switch (148) and the Hazard input
switch (149) are directly connected to the DC line.
9. The device as claimed in claim 1, wherein the input voltage sensing component (112)
comprises a combination of resistors (R20, R22 and R28) as a voltage divider for
converting input voltage to a pre-defined value, a Zener diode (Z4) for clamping
sensed input voltage, and a capacitor (C26) as a filter and a voltage stabilizer at ADC
pin of the microcontroller (100).
10. The device as claimed in claim 2, wherein the High-Beam / Low Beam Switch
sensing component (102) comprises a diode (D5) for reverse voltage protection, a
resistor (R192) to generate required minimum operating current for the switch, a
Zener diode (Z5) to clamp switch sensed voltage at an ADC pin of the microcontroller
(100), a plurality of resistors (R31, R33 and R36) as voltage divider for converting
switch voltage to pre-defined value, and a capacitor (C28) for filtering noise signal at
the ADC pin of the microcontroller (100).
11. The device as claimed in claim 2, wherein the Pass-beam Switch sensing component
(103) comprises a first diode (D6) for reverse voltage protection, a resistor (R193 and
44
R42) to generate required minimum operating current for the switch, a Zener diode
(Z7) to clamp switch sensed voltage at the ADC pin of the microcontroller (100), a
plurality of resistors (R40, R41 and R43) as voltage divider for converting switch
voltage to pre-defined value, and a capacitor (C31) for filtering noise signal at the
ADC pin of the microcontroller (100).
12. The device as claimed in claim 2, wherein the Right Winker Switch sensing
component (104) comprises a diode (D8) for reverse voltage protection, a resistor
(R194) to generate required minimum operating current for the switch, a Zener diode
(Z9) to clamp switch sensed voltage at the ADC pin of the microcontroller (100) , a
plurality of resistors (R52, R53 and R55) as voltage divider for converting switch
voltage to pre-defined value, and a capacitor (C34) for filtering noise signal at the
ADC pin of the microcontroller (100).
13. The device as claimed in claim 2, wherein the Left Winker Switch sensing component
(105) comprises a diode (D9) for reverse voltage protection, a resistor (R195) to
generate required minimum operating current for the switch, a Zener diode (Z10) to
clamp switch sensed voltage at the ADC pin of the microcontroller (100), a plurality
of resistors (R57, R58 and R60) as voltage divider for converting switch voltage to
pre-defined value, and a capacitor (C35) for filtering noise signal at the ADC pin of
the microcontroller (100).
14. The device as claimed in claim 2, wherein the Brake / Stop Switch sensing component
(106) comprises a diode (D11) for reverse voltage protection, a resistor (R197 and
R69) to generate required minimum required current for the switch, a Zener diode
(Z12) to clamp switch sensed voltage at the ADC pin of the microcontroller (100), a
plurality of resistors (R67, R68 and R70) as voltage divider for converting switch
voltage to pre-defined value, and a capacitor (C37) for filtering noise signal at the
ADC pin of the microcontroller (100).
15. The device as claimed in claim 2, wherein the Hazard Switch sensing component
(107) comprises a first diode (D10) for reverse voltage protection, a resistor (R196
and R64) to generate required minimum operating current for the switch, a Zener
diode (Z11) to clamp switch sensed voltage at the ADC pin of the microcontroller
(100), a plurality of resistors (R62, R63 and R65) as voltage divider for converting
45
switch voltage to pre-defined value, and a capacitor (C36) for filtering noise signal at
the ADC pin of the microcontroller (100).
16. The device as claimed in claim 1, wherein the engine parameter sensing component
(108) comprises a diode (D34) or a resistor (R289) for reverse voltage protection, a
Zener diode (Z6) to clamp switch sensed voltage at ADC pin of the microcontroller
(100), a plurality of resistors (R34, R37 and R38), pulled up by power supply (113),
as voltage divider for converting engine status signal voltage to pre-defined value, a
capacitor (C30) for filtering noise signal at ADC / Interrupt pin of the microcontroller
(100) and a capacitor (C29) for filtering noise signal at input status signal.
17. The device as claimed in claim 2, wherein the head lamp fault detection component
(115) comprises a combination of resistors (R8, R10 and R15) as voltage divider for
converting LED load voltage to pre-defined value, a Zener diode (Z2) to clamp switch
sensed voltage at the ADC pin of the microcontroller (100) and a capacitor (C12) for
filtering noise signal at the ADC pin of the microcontroller (100).
18. The device as claimed in claim 2, wherein the left font winker LED short detection
component (125) comprises a comparator (U5) driven through the power supply
(113), a first combination of resistors (R80 and R86) as a voltage divider for sensing
LED load voltage at positive reference of the comparator (U5), a second combination
of resistors (R84 and R87) as a voltage divider pulled up by power supply (113) for
maintaining negative reference of comparator, a resistor (R83) to limit current to an
interrupt pin of the microcontroller (100) and a capacitor (C40) for filtering noise
signal at the interrupt pin of the microcontroller (100).
19. The device as claimed in claim 2, wherein the right front winker LED short detection
component (126) comprises a comparator (U5) driven through power supply (113), a
first combination of resistors (R92 and R99) as voltage divider for sensing LED load
voltage at positive reference of the comparator, a second combination of resistors
(R96 and R100) as voltage divider pulled up by power supply (113) for maintaining
negative reference of comparator, a resistor (R95) to limit current to an interrupt pin
of the microcontroller (100) and a capacitor (C42) for filtering noise signal at the
interrupt pin of the microcontroller (100).
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20. The device as claimed in claim 2, wherein the left rear winker LED short detection
component (127) comprises a comparator (U5) driven through power supply (113), a
first combination of resistors (R113 and R119) as voltage divider for sensing LED
load voltage at positive reference of comparator, a second combination of resistors
(R117 and R120) as voltage divider pulled up by power supply (113) for maintaining
negative reference of comparator, a resistor (R116) to limit current to an interrupt pin
of the microcontroller (100) and a capacitor (C47) for filtering noise signal at the
interrupt pin of the microcontroller (100).
21. The device as claimed in claim 2, wherein the right rear winker LED short detection
component (128) comprises a comparator (U5) driven through power supply (113), a
first combination of resistors (R127 and R131) as voltage divider for sensing LED
load voltage at positive reference of comparator, a second combination of resistors
(R130 and R132) as voltage divider pulled up by power supply (113) for maintaining
negative reference of comparator, a resistor (R128) to limit current to an interrupt pin
of the microcontroller (100) and a capacitor (C49) for filtering noise signal at the
interrupt pin of the microcontroller (100).
22. The device as claimed in claim 2, wherein the High-beam LED Lamp driver
component (114) provides constant current to Headlamp LED (150 and 151) of the
vehicle, said High-beam LED Lamp driver component (114) comprises:
a Buck- boost controller / H-Bridge IC (U10);
a power inductor (L5) for H-bridge (Buck-boost) operation;
a combination of MOSFETs (Q23 and Q3) as high side and low side switches for
buck-boost operation;
a parallel combination of bulk capacitor (C148 and C170) to provide ripple-less and
constant current;
a further bulk capacitor (C103) to provide stable input voltage in case of battery less
condition;
a parallel combination of capacitors ( C104, C105, C106, C108, C162 and C165) to
filter output noise;
a plurality of capacitors (C110 and C117) to filter out noise at input and output lines
of the Buck- boost controller / H-Bridge IC (U10);
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a combination of a capacitor (C115) and a resistor (R281) or a diode (D24) for input
voltage sensing in the Buck- boost controller / H-Bridge IC (U10);
a diode (D21) to protect the Buck- boost controller / H-Bridge IC (U10) from reverse
voltage;
a resistor (R225) to configure mode of operation of the Buck- boost controller / HBridge IC (U10);
a combination of capacitors (C118 and C161) for frequency dithering;
a resistor (R226) to configure adjustable regulating frequency of the Buck- boost
controller / H-Bridge IC (U10);
a capacitor (C116) to configure soft-start time for the Buck- boost controller / HBridge IC (U10);
a capacitor (C120) to configure slope compensation for operation of the Buck- boost
controller / H-Bridge IC (U10);
a combination of resistor (R24) and capacitors (C121 and C119) for output of error
amplifier and compensate for error feedback of loop for operation of the Buck- boost
controller / H-Bridge IC (U10);
a combination of resistors (R25 and R35) to provide output voltage feedback for
operation of the Buck- boost controller / H-Bridge IC (U10);
a combination of resistors (R264, R263 and R267) and a capacitor (C174) to switch
On/Off the Buck- boost controller / H-Bridge IC (U10) depending on input voltage;
a transistor (Q27) to enable the Buck- boost controller / H-Bridge IC (U10);
a combination of resistor (R217 and R262) for biasing transistor (Q27);
a capacitor (C174) to filter noise at transistor (Q27);
a combination of resistors (R233 and R234) and a capacitor (C122) to provide
feedback to the Buck- boost controller / H-Bridge IC (U10) for constant current loop
for output load;
a resistor (R215) to configure constant current output;
a resistor (R229) to limit current flow through power inductor (L5);
a resistor (R227) for internal operation of the Buck- boost controller / H-Bridge IC
(U10);
a capacitor (C113) for filtering noise at Vcc of the Buck- boost controller / H-Bridge
IC (U10);
a plurality of resistors (R19, R218, R219 and R224) for current limiting during
switching of MOSFET;
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a combination of resistor (R251 and R252), capacitor (C111 and C112) and diode (D7
and D14) for switching of MOSFET; and
a diode (D26) as reverse voltage protection.
23. The device as claimed in claim 2, wherein the Low-beam LED lamp driver
component (116) is driven by the High-beam LED Lamp driver component (114) and
provides switching between High beam LEDs and Low beam LEDs, said Low-beam
LED lamp driver component (116) comprises:
a MOSFET (Q2) as a switch to change LED mode;
a combination of resistors (R21 and R189) for biasing the MOSFET (Q2);
a transistor (Q17) to control switching of MOSFET (Q2);
a combination of resistors (R190 and R191) for biasing transistor (Q17);
a Zener diode (Z18) to protect MOSFET (Q2) Source to Gate from over-voltage;
a combination of resistor (R188) and capacitors (C71 and C173) for increasing
switching time of MOSFET (Q2);
a plurality of capacitors (C93, C72, C176 and C177) as noise filters at output and
transistors;
a combination of transistors (Q28 and Q29) to force shut down the MOSFET (Q2) in
LED make & break condition;
a combination of resistors (R278 and R279) for biasing transistor (Q29);
a combination of resistor (R275) and a Zener diode (Z23) for biasing and turn ON
transistor (Q28) above certain voltage;
a combination of resistors (R271, R274 and R276) for translating LED voltage in
make & break condition; and
a diode (D25) as over voltage protection.
24. The device as claimed in claim 2, wherein the Buck converter component (117)
provides constant voltage to each of the Switch Illumination LED lamp driver
component (118); the Position indicating LED lamp driver component (119); the Leftfront LED Winker lamp driver component (120); the Right-front LED Winker lamp
driver component (121); the Left-rear LED Winker lamp driver component (122); the
Right-rear LED Winker lamp driver component (123); the Stop/Tail LED lamp driver
component (124); said Buck converter component (117) comprises:
49
a step down switching voltage regulator IC (U3) as constant voltage source for
constant current LED drivers (118-124);
a pair of capacitors (C21 and C22) as noise filter in input supply line of the step down
switching voltage regulator IC (U3);
a capacitor (C24) as noise filter in output line of the step down switching voltage
regulator IC (U3);
a resistor (R26) to configure regulation frequency of the step down switching voltage
regulator IC (U3);
a capacitor (C25) for soft start of the step down switching voltage regulator IC (U3);
a combination of resistors (R259, R260 and R268) and a capacitor (C175) to switch
On/Off the step down switching voltage regulator IC (U3) depending on input
voltage;
a power inductor (L4) for stepping down battery voltage and providing constant
voltage for constant current drivers;
a bulk capacitor (C23) for stable and ripple less constant voltage;
a combination of a resistor (R213) and a capacitor (C20) for efficient switching of
inbuilt MOSFET of the step down switching voltage regulator IC (U3);
a diode (D4) as free-wheeling diode for voltage regulation of the step down switching
voltage regulator IC (U3); and
a combination of resistors (R23 and R27) for providing output voltage feedback to the
step down switching voltage regulator IC (U3).
25. The device as claimed in claim 2, wherein each of the Left-front LED Winker lamp
driver component (120); the Right-front LED Winker lamp driver component (121);
the Left-rear LED Winker lamp driver component (122); and the Right-rear LED
Winker lamp driver component (123) is driven by the Buck converter component
(117) to provide constant current to Left front winker LED (134), Right Front winker
LED (135), Left Rear winker LED (136) and Right rear winker LED (137).
26. The device as claimed in claim 25, wherein the Left-front LED Winker lamp driver
component (120); the Right-front LED Winker lamp driver component (121); the
Left-rear LED Winker lamp driver component (122); and the Right-rear LED Winker
lamp driver component (123) comprises:
a linear current driver IC (U4) as constant current source for LEDs (134-137);
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a capacitor (C39) as noise filter in input supply line of the linear current driver IC
(U4);
a combination of resistors (R76 and R269) for protecting MCU pin and to detect LED
open fault condition;
a combination of capacitors (C83 and C84) as noise filters at feedback pins of the
linear current driver IC;
a combination of resistors ( R85, R88, R94 and R101) as current setting elements;
a combination of transistors (Q5, Q6, Q7 and Q8) as ON/OF switch for winker LEDs
(134-137);
a diode (D30, D31, D32 and D35) or resistor (R282, R283, R284 and R285) as
reverse voltage protection; and
a combination of capacitors (C150, C166, C151, C167, C86, C168, C89 and C169) as
noise filters at LED output.
27. The device as claimed in claim 2, wherein the Stop/Tail LED lamp driver component
(124) is driven by the Buck converter component (117) to provide constant current to
stop/tail LED (138), said Stop/Tail LED lamp driver component (124) comprises:
a linear current driver IC (U7) as constant current source for LEDs (138);
a first capacitor (C52) as noise filter in input supply line of the linear current driver IC
(U7);
a combination of resistors (R141 and R143) for protecting MCU pin and to detect
LED open fault condition;
a combination of capacitors (C80 and C95) as noise filters at feedback pins of the
linear current driver IC;
a combination of resistors ( R150, R151, R152 and R153) as current setting elements;
a pair of transistors (Q11 and Q24) as ON/OF switch for stop and tail LEDs (138);
a diode (D27) or resistor (R286) as reverse voltage protection; and
a combination of capacitors (C54and C55) as noise filters at LED output.
28. The device as claimed in claim 2, wherein each of the Switch Illumination LED lamp
driver component (118) and the Position indicating LED lamp driver component
(119) is driven by the Buck converter component (117) to provide constant current to
switch illumination LED (132) and position LED (133), the Switch Illumination LED
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lamp driver component (118) and the Position indicating LED lamp driver component
(119) comprising:
a linear current driver IC (U8) as constant current source for LEDs (132 and 133);
a first capacitor (C62) as noise filter in input supply line of the linear current driver IC
(U8);
a combination of resistors (R171 and R173) for protecting MCU pin and to detect
LED open fault condition;
a combination of capacitors (C81 and C96) as noise filters at feedback pins of the
linear current driver IC (U8);
a combination of resistors ( R177, R178, R179 and R180) as current setting elements;
a pair of transistors (Q25 and Q19) as ON/OF switch for switch illumination and
position LEDs (132-133);
a Zener diode (Z19) to distribute power dissipation at switch illumination LED;
a diode (D28 and D29) or resistor (R287and R288) as reverse voltage protection; and
a combination of capacitors (C64, C172, C97 and C171) as noise filters at LED
output.
29. The device as claimed in claim 2, wherein the right winker cluster indicator lamp
driver component (129) comprises:
a transistor (Q9) acting as an ON/OFF switch for LED-based right winker cluster
indicator lamp (141);
a resistor (R135) as current limiter through transistor(Q9) during ON time;
a combination of resistors (R136 and R140) for biasing transistor (Q9); and
a combination of capacitors (C53 and C98) as noise filters.
30. The device as claimed in claim 2, wherein the Left Winker Cluster indicator lamp
driver component (130) comprises:
a transistor (Q10) acting as an ON/OFF switch for the LED-based Left Winker
Cluster indicator lamp (140);
a resistor (R144) as current limiter through transistor(Q10) during ON time;
a combination of resistors (R147 and R149) for biasing transistor (Q10); and
a combination of capacitors (C56 and C91) as noise filters.
31. The device as claimed in claim 2, wherein the High Beam Cluster indicator lamp
driver component (131) comprises:
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a transistor (Q12) acting as an ON/OFF switch for the LED-based High beam Cluster
indicator lamp (139);
a resistor (R154) as current limiter through transistor(Q12) during ON time;
a combination of resistors (R157 and R159) for biasing transistor (Q12); and
a combination of capacitors (C58 and C92) as noise filters;
32. The device as claimed in claim 1, wherein the microcontroller (100) is a 16-bit
microcontroller, wherein a combination of a first diode (D12), a resistor (R181), and a
capacitor (C66) is used for RESET pin of the microcontroller (100), wherein a second
capacitor (C67) is used as an Internal Work at a REGC pin of the microcontroller
(100), wherein a third capacitor (C65) may be used as a filter for noise signal and as a
voltage stabilizer at a input supply pin of the microcontroller (100), a combination of
resistors (R182 and R183) pulled up by regulated power supply (113) for external
crystal pins of microcontroller (100) and wherein a connector (J2) is used for
programming the microcontroller (100).