DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION

(See Section 10 and Rule 13)

Title of invention:
A HYBRID MODULATION ARRANGEMENT FOR A VEHICLE LIGHTING SYSTEM

APPLICANT:
Varroc Engineering Limited
An Indian entity having address as:
L-4, MIDC Waluj,
Aurangabad-431136,
Maharashtra, India

.

The following specification describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
The present disclosure relates to a headlamp in automobiles. More specifically, the disclosure relates to a hybrid modulation arrangement for a lighting system in a vehicle. .
BACKGROUND
The subject matter discussed in the background section should not be assumed to be prior art merely because of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
In the conventional art, a Class D headlamp includes an LED load of around 25W and 16W in High Beam (HB) mode and Low Beam (LB) mode respectively. In order to fulfil power requirement of two-wheeler headlamp to meet light class D criteria the step-down converter topology is used.
In the conventional headlamp assembly described above, as the DC-DC regulators used, the headlamp assembly may require external inductor, bulk capacitor, and dedicated application-specific integrated DC -DC circuit, (ASIC DC-DC) to provide constant light output throughout the range. However, the complexity of a circuit of the headlamp assembly increases with increase in the number of components to drive LED load, thereby resulting in high form factor. Specifically, the functionalities like switching regulators operating at high frequency results in high frequency noise. This leads to low Electromagnetic Compatibility (EMI/EMC) performance which may require good amount of EMC filters and thereby leading to overall increase in the manufacturing cost.
Therefore, there is an utmost need of an improved class D two-wheeler headlamp assembly using a step-down converter without any magnetic components and without any freewheeling diode path, thereby making a ‘hybrid of both DC -DC and linear regulator topology’ and meeting the statutory requirements of class D light projection.
SUMMARY
This summary is provided to introduce concepts related to a hybrid modulation arrangement for a vehicle lighting system and a method for the same. The concepts are for a hybrid modulation for class D two-wheeler headlamp and the concepts are further described below in the detailed description. The assembly of hybrid modulation may be equipped with step-down converters along-with constant current linear regulators. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
In an implementation of the present disclosure a hybrid modulation arrangement for a vehicle lighting system is disclosed. In accordance with an exemplary embodiment, the hybrid modulation arrangement comprises a first circuit arrangement configured to shun voltage spikes and reverse polarities from an input voltage (Vin). The hybrid modulation arrangement further comprises a second circuit arrangement configured as a step-down voltage regulator and configured to generate a constant voltage. The step-down voltage regulator may further comprise a plurality of MOSFETs, at least one bulk capacitor, a plurality of transformers for operating the plurality of MOSFETs, and a PWM controller circuit block. In accordance with the implementation the first circuit arrangement may be configured to provide (Vin) to the second circuit arrangement and charge the at least one bulk capacitor. The PWM controller circuit block may be further configured to adjust ON time of the plurality of MOSFETs of the second circuit arrangement to generate the constant voltage. A third circuit arrangement in accordance with the present implementation may comprise a plurality of transistors and a plurality of resistors configured to receive a constant voltage from the second circuit arrangement, and regulate and provide a constant current to a plurality of light sources of the vehicle lighting system.
In another implementation of the present disclosure a method of a hybrid modulation in a vehicle lighting system is disclosed. The method comprises the steps of removing transient voltage spikes and reverse polarities from an input voltage (Vin). A constant voltage is generate through a step-down voltage regulator, wherein ON time of the plurality of MOSFETs in the step-down voltage regulator are adjusted using a pulse width modulation (PWM) controller circuit block for generating the constant voltage. The method further comprises a step of regulating and providing a constant current to a plurality of light sources of the vehicle illumination system.
BRIEF DESCRIPTION OF DRAWINGS
The detailed description is described with reference to the accompanying Figures.
In the Figures, the left-most digit(s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout
the drawings to refer like features and components.
Figure 1 illustrates a block diagram 100 of the hybrid modulation arrangement in a vehicle lighting system, in accordance with an embodiment of the present subject matter.
Figure 2a illustrates a Low Beam Driver Circuit 200 circuit arrangement, in accordance with an embodiment of a present subject matter.
Figure 2b illustrates a first circuit arrangement 210 for a low beam driver circuit, in accordance with an embodiment of a present subject matter.
Figure 2c illustrates a second circuit arrangement 220 for a low beam driver circuit, in accordance with an embodiment of a present subject matter.
Figure 2d illustrates a third circuit arrangement 230 for a low beam driver circuit, in accordance with an embodiment of a present subject matter.
Figure 3a illustrates a High Beam Driver Circuit 300 circuit arrangement, in accordance with an embodiment of a present subject matter.
Figure 3b illustrates a first circuit arrangement 310 for a high beam driver circuit, in accordance with an embodiment of a present subject matter.
Figure 3c illustrates a second circuit arrangement 320 for a high beam driver circuit, in accordance with an embodiment of a present subject matter.
Figure 3d illustrates a third circuit arrangement 330 for a high beam driver circuit, in accordance with an embodiment of a present subject matter.
Figure 4 illustrates a flowchart of a method 400 of the hybrid modulation arrangement in a vehicle lighting system, in accordance with an embodiment of a present subject matter.
Figure 5 illustrates an integrated view 500 of a microcontroller interface, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items.
It must also be noted that, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary methods are described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
The present disclosure relates to a hybrid modulation arrangement for a lighting system in a vehicle. The arrangement includes several circuit arrangements vis a vis a first, second and a third circuit arrangements in both the conditions of Low Beam (LB) and High Beam (HB).
The first circuit arrangement is an input protection circuit arrangement. The input protection circuit arrangement is configured to shun voltage spikes and reverse polarities from any uptick in input voltage. For the low beam driver circuit, the input protection circuit arrangement includes a plurality of capacitors, preferably two capacitors C2 and C5 which are arranged in series. A transient voltage suppression (TVS) diode D2 to shunt the voltage spike, and a reverse polarity diode D2. The TVS diode D2 are arranged in parallel with the plurality of capacitors, C2 and C5.
For the high beam driver circuit, the input protection circuit arrangement includes a plurality of capacitors, preferably two capacitors C12 and, a transient voltage suppression (TVS) diode D6 to shunt the voltage spike, and a reverse polarity diode D4. The TVS Diode D2 are arranged in parallel with the plurality of capacitors, C12 and C17.
The second circuit arrangement is a constant voltage generator circuit. The constant voltage generator circuit is configured as a step-down voltage regulator (a step-down DC-DC converter) to generate a constant voltage. For the low beam driver circuit, the constant voltage generator circuit arrangement includes a plurality of MOSFETs (Q1, Q4, and Q7), at least one bulk capacitor (C4), a plurality of capacitors (C1, C3, C7, and C8), wherein Q1 and Q4 are P-channel enhancement types and Q7 is a N-channel enhancement type, a plurality of resistors (R9, R10, R11, R15, R26, R27, R31, and R32), a plurality of transistors for operating the plurality of MOSFETs, a Zener diode (ZD1), and a Pulse Width Modulation (PWM) controller circuit block (LB_PWM).
For the high beam driver circuit, the constant voltage generator circuit arrangement includes a plurality of MOSFETs (Q8, Q11, and Q14), at least one bulk capacitor (C14), a plurality of capacitors (C11, C13, C25, and C26), wherein Q8 and Q11 are P-channel enhancement types and Q14 is a N-channel enhancement type, a plurality of resistors (R50, R51, R52, R57, R68, R69, R74, and R75), a plurality of transistors for operating the plurality of MOSFETs, a Zener diode (ZD2), and a Pulse Width Modulation (PWM) controller circuit block (HB_PWM).
Further, a feedback circuit block and a fault detection feedback circuit blocks are in communication with the PWM controller circuit block. For a low beam driver circuit, the fault detection feedback circuit block is present in communication with the PWM Controller circuit block which includes a plurality of resistors (R33 and R35) and a capacitor (C10) for LED load (LB_LED1) and a plurality of resistors (R34 and R36) and a capacitor (C9) for LB_LED2.
For a high beam driver circuit, the fault detection feedback circuit block is present in communication with the PWM Controller circuit block which includes a plurality of resistors for HB_LED1_Fault 1, and a plurality of resistors (R79 and R83) and a capacitor (C27) for HB_LED2_Fault 2.
The third circuit arrangement is a constant current generator circuit. The constant current generator circuit is configured to receive a constant voltage from the second circuit arrangement and regulate and provide a constant current to a plurality of light sources of the vehicle lighting system. For the Low beam driver circuit, the Low Beam_LED 1 circuit (LB_LED 1) comprises a plurality of resistors (R1, R2, R3, R4-1206, R12, R14, R16, R17, R18, R19, R20, R28, and R30), a plurality of p-n-p transistors (Q2 and Q5), and a single capacitor (C6).
Similarly, the low beam LED 2 (LB_LED2) comprises a plurality of resistors (R5, R6, R7, R8, R21, R22, R23, R24, R25, R13, and R29), a plurality of p-n-p transistors (Q3 and Q6), and no capacitor.
For the high beam driver circuit, the High Beam_LED 1 circuit (HB_LED 1) comprises a plurality of resistors (R42, R43, R44, R45, R54, R56, R58, R59, R60, R61, R62, R70, and R73), a plurality of p-n-p transistors (Q9 and Q12), and a single capacitor (C18).
Similarly, the High Beam_LED 2, LB_LED2 comprise a plurality of resistors (R46, R47, R48, R49, R55, R63, R64, R65, R66, R67, and R72), a plurality of p-n-p transistors (Q10 and Q13), and no capacitor.
Further, the hybrid modulation arrangement for a vehicle lighting system with the DC-DC step-down converter with constant current linear regulator is related for class D two-wheeler headlamp. The headlamps of automobile are controlled by digital output from microcontroller interface to provide a constant light output throughout the operating range of 9V-16V battery voltage. More specifically, the present disclosure presents the DC-DC step down converter which does not comprise any magnetic components (inductor or transformer) and freewheeling diode and thereby making it a cost-effective system.
It should be noted that a Low Beam Driver Circuit and a High Beam Driver Circuit arrangements are almost similar. Further, the components of the hybrid modulation arrangements in the vehicle lighting system are present in both the Low Beam Driver Circuit (figure 2a-2c) and the High Beam Driver Circuit (figure 3a-3c). Therefore, the referral numerals are kept same for the same components (singular circuit and plural circuits) in each Low and High beam Driver circuits.
Referring to figure 1, a basic block diagram 100 of the hybrid modulation arrangement in a vehicle lighting system is illustrated, in accordance with an embodiment of the present subject matter. The headlamp assembly may comprise an input protection circuit 101, a step-down voltage regulator (hereinafter referred as a step-down DC-DC converter) 102, a PWM controller circuit block 103, a feedback circuit block 104 (along with a feedback circuit block 104, a fault detection circuit block is also present which is not shown in the diagram), a plurality of constant current source/regulator 105 with LEDs (LED1 to LED10).
Referring figure 2a, a Low Beam Driver Circuit 200 is illustrated, in accordance with an embodiment of a present subject matter. The low beam driver circuit 200 includes three circuit arrangements, viz-a-viz a first circuit arrangement 210, a second circuit arrangement 220, and a third circuit arrangement 230.
Referring figure 2b, a first circuit arrangement 210 is shown, in accordance with an embodiment of a present subject matter. The first circuit arrangement 210 is the input protection circuit 101. The input protection circuit 101 is configured to protect the circuitry components from heating due to voltage spikes and reverse polarities. The input protection circuit 101 includes a plurality of capacitors, TVS diodes, and reverse polarity diodes. The first circuit arrangement 210 is configured to provide the input voltage (Vin) to the second circuit arrangement and charge the at least one bulk capacitor.
Referring figure 2c, a second circuit arrangement 220 is shown, in accordance with an embodiment of a present subject matter. The second circuit arrangement 220 is the constant voltage generator circuit 102. The constant voltage generator circuit 102 is configured as step-down voltage regulators, and configured to generate a constant voltage. The step-down voltage regulator comprises a plurality of MOSFETs, at least one bulk capacitor in each driver circuits, a plurality of capacitors, a plurality of resistors, a plurality of transistors for operating the plurality of MOSFETs, Zener diodes, and Pulse Width Modulation (PWM) controller circuit block 103. The (Vin) from the first circuit arrangement 210 is received by the second circuit arrangement 220. (Vin) also charges the bulk capacitors of each driver circuits.
Further, the PWM controller circuit block 103 adjusts the ON time of the plurality of the MOSFETs of the second circuit arrangement 220 to generate a constant voltage. The PWM controller circuit block 103 of the second circuit arrangement 220 is configured to adjust ON time of the plurality of MOSFETs. The PWM controller circuit block 103 of the second circuit arrangement 220 is further communicatively connected to the feedback circuit block 104 and fault detection circuit blocks (not shown). The feedback circuit block 103 is further configured to sense an output voltage (Vout) across the plurality of light sources and to generate an output feedback voltage (Vfb) for the PWM controller circuit block 103. The PWM controller circuit block 103 is also configured to receive the output feedback voltage (Vfb) of the fault detection circuit blocks, compare the output feedback voltage (Vfb) with a pre-determined voltage, detect at least one light source failure based on the comparison.
The second circuit arrangement 220 is further configured to provide a minimum threshold voltage to the plurality of linear regulators. Further, the plurality of MOSFETs is set at a constant frequency of lower than 100 KHz. The plurality of MOSFETs is operated by the plurality of transistors. The current to charge the bulk capacitors flow through the plurality of MOSFETs of the step-down voltage regulators 102 arranged in the second circuit arrangement 220.
Referring figure 2d, a third circuit arrangement 230 is shown, in accordance with an embodiment of a present subject matter. The third circuit arrangement 230 comprises a plurality of linear regulators (constant current generator circuits) 105. The linear regulators 105 have a plurality of transistors and a plurality of resistors. The linear regulators 105 are configured to receive a constant voltage from the second circuit arrangement 220 and regulate and provide a constant current to a plurality of light sources of the vehicle lighting system. Further, the plurality of transistors has transistor voltage which along with one resistor of the third circuit arrangement 230 is configured to determine an amount of current flowing through the plurality of light sources (LED1 to LED10).
Referring figure 3a, a High Beam Driver Circuit 300 is illustrated, in accordance with an embodiment of a present subject matter. The high beam driver circuit 300 also includes three circuit arrangements and is similar to the low beam driver circuit 200 as shown in figures 2a-2d, viz-a-viz a first circuit arrangement 310, a second circuit arrangement 320, and a third circuit arrangement 330.
Referring figure 3b, a first circuit arrangement 310 is shown, in accordance with an embodiment of a present subject matter. The first circuit arrangement 310 is the input protection circuit 101. The input protection circuit 101 is configured to protect the circuitry components from heating due to voltage spikes and reverse polarities. The input protection circuit 101 includes a plurality of capacitors, TVS diodes, and reverse polarity diodes. The first circuit arrangement 310 is configured to provide the input voltage (Vin) to the second circuit arrangement and charge the at least one bulk capacitor.
In figure 3c, a second circuit arrangement 320 is shown, in accordance with an embodiment of a present subject matter. The second circuit arrangement 320 is the constant voltage generator circuit 102. The constant voltage generator circuit 102 is configured as step-down voltage regulators, and configured to generate a constant voltage. The step-down voltage regulator comprises a plurality of MOSFETs, at least one bulk capacitor in each driver circuits, a plurality of capacitors, a plurality of resistors, a plurality of transistors for operating the plurality of MOSFETs, Zener diodes, and Pulse Width Modulation (PWM) controller circuit block 103. The (Vin) from the first circuit arrangement 310 is received by the second circuit arrangement 320. (Vin) also charges the bulk capacitors of each driver circuits.
Further, the PWM controller circuit block 103 adjusts the ON time of the plurality of the MOSFETs of the second circuit arrangement 320 to generate a constant voltage. The PWM controller circuit block 103 of the second circuit arrangement 320 is configured to adjust ON time of the plurality of MOSFETs. The PWM controller circuit block 103 of the second circuit arrangement 320 is further communicatively connected to the feedback circuit block 104 and fault detection circuit blocks (not shown). The feedback circuit block 103 is further configured to sense an output voltage (Vout) across the plurality of light sources and to generate an output feedback voltage (Vfb) for the PWM controller circuit block 103. The PWM controller circuit block 103 is also configured to receive the output feedback voltage (Vfb) of the fault detection circuit blocks, compare the output feedback voltage (Vfb) with a pre-determined voltage, detect at least one light source failure based on the comparison.
The second circuit arrangement 320 is further configured to provide a minimum threshold voltage to the plurality of linear regulators. Further, the plurality of MOSFETs is set at a constant frequency of lower than 100 KHz. The plurality of MOSFETs is operated by the plurality of transistors. The current to charge the bulk capacitors flow through the plurality of MOSFETs of the step-down voltage regulators 102 arranged in the second circuit arrangement 320.
Referring figure 3d, a third circuit arrangement 330 is shown, in accordance with an embodiment of a present subject matter. The third circuit arrangement 330 comprises a plurality of linear regulators (constant current generator circuits) 105. The linear regulators 105 have a plurality of transistors and a plurality of resistors. The linear regulators 105 are configured to receive a constant voltage from the second circuit arrangement 320 and regulate and provide a constant current to a plurality of light sources of the vehicle lighting system. Further, the plurality of transistors has transistor voltage which along with one resistor of the third circuit arrangement 330 is configured to determine an amount of current flowing through the plurality of light sources (LED1 to LED10).
It should be noted that a Low Beam Driver Circuit and a High Beam Driver Circuit arrangements are almost similar. Further, the components of the hybrid modulation arrangements in the vehicle lighting system are present in both the Low Beam Driver Circuit (figure 2a-2c) and the High Beam Driver Circuit (figure 3a-3c). Therefore, the referral numerals are kept same for the same components (singular circuit and plural circuits) in each Low and High beam Driver circuits.
Therefore, the hybrid modulation arrangement for a lighting system in vehicle comprises: first circuit arrangements (210, 310) which are configured to shun voltage spikes and reverse polarities from an input voltage (Vin), second circuit arrangements (220, 320) configured as a step-down voltage regulator and configured to generate a constant voltage, wherein the step-down voltage regulators comprise: a plurality of MOSFETs; at least one bulk capacitors; a plurality of transistors for operating the plurality of MOSFETs; and pulse width modulation (PWM) controller circuit blocks (103), wherein the first circuit arrangements (210, 310) are configured to: provide the input voltage (Vin) to the second circuit arrangements (220, 320), and charge the at least one bulk capacitor, and wherein the PWM controller circuit blocks (103) are configured to adjust ON time (Ton) of the plurality of MOSFETs of the second circuit arrangements (220, 320) to generate the constant voltage; and third circuit arrangements (230, 330) comprising a plurality of linear regulators, each linear regulator comprising a plurality of transistors and a plurality of resistors configured to: receive a constant voltage from the second circuit arrangements (220, 320), and regulate and provide a constant current to a plurality of light sources of the vehicle lighting system.
Now, referring figure 4, flowchart of a method 400 of the hybrid modulation in a vehicle lighting system is described. The method comprises a Step S410, for removing transient voltage spikes and reverse polarities from an input voltage (Vin). Further at step S420, a constant voltage is generated through a step-down voltage regulator, wherein ON time of the plurality of MOSFETs in the step-down voltage regulator are adjusted using a pulse width modulation (PWM) controller circuit block for generating the constant voltage. At Step S430, in accordance with the present disclosure, the method comprises regulating and providing a constant current to a plurality of light sources of the vehicle illumination system.
Figure 5 shows a microcontroller interface 500. The microcontroller interface 500 is configured to control the ON time of the plurality of MOSFETs. Referring both diagrams figure 4 and figure 5, a method of the hybrid modulation of a vehicle lighting system is described. At step S410, transient voltage spikes and reverse polarities are removed from the input voltage (Vin) in the input protection circuits 101 of the first circuit arrangement 210, 310. From the first circuit arrangement 210, 310, (Vin) goes to the second circuit arrangement 220, 320. At step S420, a constant voltage is generated through the step-down voltage regulators which are constant voltage generator circuits 102. In this the plurality of MOSFETs in the constant voltage generator circuits 102 is regulated by the PWM controller circuit blocks 103. In one non-limiting embodiment, the PWM controller can be a microcontroller interface 500. However, the PWM controller is not limited to above example and any other PWM controller used for performing the above-mentioned functionality is well within the scope of the present disclosure. The ON time of the plurality of MOSFETs in the step-down voltage regulators are adjusted using the PWM controller circuit blocks 103 for generating the constant voltage. Further, in step S430, a constant current is regulated and provided to a plurality of light sources (LED1 to LED10) of the vehicle illumination system.
The feedback circuit blocks 104 sense the output voltage (Vout) across the plurality of light sources (LED1 to LED 10) and generate the output feedback voltage (Vfb) for the PWM controller circuit blocks 103. The PWM controller circuit blocks 103 then receive the output feedback voltage (Vfb) of the fault detection feedback circuit block and compares the (Vfb) with a pre-determined voltage value to detect light source (at least one light source) failure based on the said comparison. Once detected, the light sources are turned off of the vehicle illumination system.
The above-mentioned embodiments require the frequency of switching the plurality of MOSFETs as constant and set to be in lower range than 100 KHz., in order to reduce or eliminate the bulky EMC filters thereby enabling it to meet EMC requirements. Further, the peak current to charge the capacitor may be configured to flow through the plurality of MOSFETs and the bulk capacitors of the step down thereby eliminating the usage of inductor and freewheeling diode. Here, to ensure low thermal rise on the MOSFET, more thermal areas like copper area and/or thermal vias on PCB may be added to the switching MOSFET (202) into the step-down voltage regulator 102.
In another embodiment, the constant current linear sources/ regulators 105 may comprise of two transistors. A voltage drop occurs at emitter from base (Vbe) of a transistor which may determine the amount of current flowing through the LEDs. The Bypass power sharing resistors may be added to manage the power dissipation and thereby managing the temperature rise in the power transistors. It must be noted that the required voltage may be fed to the constant current regulators and the LED load, thereby the power dissipation and the thermal rise on the linear regulators can be minimized.
In one non-limiting embodiment of the present disclosure, the above-mentioned circuits may be implemented by replacing the N-type MOSFETs with P-type MOSFETs and P-type MOSFETs with N-type MOSFETs along with minor modification in the circuit arrangement.
The aforementioned illustrated embodiments offer the following advantages over the conventional headlamp assembly, which may include but are not limited to:
• The present disclosure provides a headlamp without any magnetic component (Inductor/Transformer) and without Freewheeling diode thereby making it a low-cost headlamp having a low form factor.
• The present hybrid modulation for class D two-wheeler headlamp employs feedback controlled, auto adjusted time TON and TOFF per duty cycle of MOSFETs by taking feedback loop from the output voltage.
• The present disclosure provides a headlamp with a fixed switching frequency of regulators over the operating voltage range from 9V to 16V.
• The present disclosure discloses a headlamp that may be realized by communizing the microcontroller part of auto components in the vehicle by making use of few required GIPO’s such as instrument cluster, ECU, CDI, ISG, etc. This microcontroller platform may change the threshold values in the software thereby making it universal for multiple variants of the vehicles.
• The present disclosure provides a system and method of hybrid modulation for class D two-wheeler having the feedback circuit which may detect LED failure, thereby the microcontroller/PWM controller can permanently turn off the MOSFETs, hence avoiding losses in the system.
The embodiments, examples and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The foregoing description shall be interpreted as illustrative and not in any limiting sense. A person of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For limiting the scope of the invention, a subsequent Complete Specification will be filed to determine the true scope and content of this disclosure.
Although the implementations for the hybrid modulation arrangement for a vehicle lighting system have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for the hybrid modulation arrangement circuits along with as disclosed components.
,CLAIMS:WE CLAIM:
1. A hybrid modulation arrangement for a lighting system in vehicle, the hybrid modulation arrangement comprising:
first circuit arrangements (210, 310) configured to shun voltage spikes and reverse polarities from an input voltage (Vin);
second circuit arrangements (220, 320) configured as a step-down voltage regulator and configured to generate a constant voltage, wherein the step-down voltage regulators comprise:
a plurality of MOSFETs;
at least one bulk capacitors;
a plurality of transistors for operating the plurality of MOSFETs; and
pulse width modulation (PWM) controller circuit blocks (103), wherein the first circuit arrangements (210, 310) are configured to:
provide the input voltage (Vin) to the second circuit arrangements (220, 320), and charge the at least one bulk capacitor, and
wherein the PWM controller circuit blocks (103) are configured to adjust ON time (Ton) of the plurality of MOSFETs of the second circuit arrangements (220, 320) to generate the constant voltage; and
third circuit arrangements (230, 330) comprising a plurality of linear regulators, each linear regulator comprising a plurality of transistors and a plurality of resistors configured to:
receive a constant voltage from the second circuit arrangements (220, 320), and
regulate and provide a constant current to a plurality of light sources of the vehicle lighting system.
2. The hybrid modulation arrangement as claimed in claim 1, further comprising:
feedback circuit blocks (104) and fault detection feedback circuit blocks are in communication with the PWM controller circuit blocks (103).
3. The hybrid modulation arrangement as claimed in claim 2, wherein the feedback circuit blocks (104) are configured to:
sense an output voltage (Vout) across the plurality of light sources, and
generate an output feedback voltage (Vfb) for the PWM controller circuit blocks (103).
4. The hybrid modulation arrangement as claimed in claim 3, wherein the PWM controller circuit blocks (103) is configured to:
receive the output feedback voltage (Vfb) voltage of the fault detection feedback circuit blocks,
compare the output feedback voltage (Vfb) with a predetermined voltage;
detect at least one light source failure based on the comparison, and
turn off the plurality of light sources if the at least one light source failure is detected.
5. The hybrid modulation arrangement as claimed in claim 1, wherein the plurality of MOSFETs is set at a constant frequency lower than 100 KHz.
6. The hybrid modulation arrangement as claimed in claim 1, wherein a current to charge the at least one bulk capacitor flows through the plurality of MOSFETs of the step-down voltage regulator.
7. The hybrid modulation arrangement as claimed in claim 1, wherein at least one transistor voltage of the third circuit arrangements (230, 330) and at least one resistor of the third circuit arrangements (230, 330) determine an amount of current flowing through the plurality of light sources.
8. The hybrid modulation arrangement as claimed in claim 1, wherein the second circuit arrangements (220, 320) are configured to provide a minimum threshold voltage to the plurality of linear regulators (105).
9. A method of a hybrid modulation in a vehicle illumination system, the method comprising:
removing transient voltage spikes and reverse polarities from an input voltage Vin;
generating a constant voltage through a step-down voltage regulator, wherein ON time of the plurality of MOSFETs in the step-down voltage regulator are adjusted using a pulse width modulation (PWM) controller circuit blocks (103) for generating the constant voltage; and
regulating and providing a constant current to a plurality of light sources of the vehicle illumination system.
10. The method as claimed in claim 9, further comprising:
sensing an output voltage (Vout) across the plurality of light sources of the vehicle illumination system;
generating an output feedback voltage (Vfb) for the PWM controller circuit blocks (103);
comparing the output feedback voltage (Vfb) with a predetermined voltage;
detecting at least one light source failure based on the said comparison; and
turning off the plurality of light sources of the vehicle illumination system if the at least one light source failure is detected.

Dated this 29th day of April, 2021

Priyank Gupta
Agent for the Applicant
IN/PA-1454