Claims:WE CLAIM:

1. A blinker control circuit 100, comprising:
an astable multivibrator 101 configured for oscillating at a base frequency in order to turn ON/OFF of a blinker;
an output driver 102 configured for receiving ON/OFF signal from the astable multivibrator 101, wherein the ON/OFF signal controls the turning ON/OFF of the blinker based upon the oscillation of the astable multivibrator 101 at a base frequency;
a fault latch 104 configured to be enabled based upon an output signal received from the output driver 102;
a fault detector 103 electronically coupled with the output driver 102, wherein the fault detector 103 is configured for checking a current in the output driver 102, wherein when the current in the output driver 102 is above a minimum threshold, the fault detector 103 generates a fault clear signal thereby disabling the fault latch 104; and
a frequency doubler 105 configured to receive an enable signal or a disable signal from the fault latch 104 depending upon the enabling or disabling of the fault latch 104 respectively, and wherein the enable signal activates the frequency doubler 105 to switch the astable multivibrator 101 to oscillate at the double frequency of the base frequency, and wherein the disable signal enables the astable multivibrator 101 to continue to oscillate at the base frequency.

2. The blinker control circuit 100 as claimed in claim 1, wherein the astable multivibrator 101 is configured to oscillate at the base frequency ranging from 1.5 to 1.83Hz.

3. The blinker control circuit 100 as claimed in claim 1, wherein the astable multivibrator 101 comprises transistors (Q1 and Q2) arranged in parallel, capacitors (C1, C2), and resistors R1, R2, R3, R4, wherein the resistors R1 and R4 act as load resistors, wherein R2C1 and R3C2 are configured for changing the time constant of the astable multivibrator 101.

4. The blinker control circuit 100 as claimed in claim 1, wherein the frequency doubler 105 comprises resistors (R6 and R7), wherein resistors R6 and R7, arranged parallel to resistors R2 and R3 of the astable multivibrator 101 respectively, when switched on are adapted to change the time constant of the astable multivibrator 101 to double the base frequency.

5. The blinker control circuit 100 as claimed in claim 1, wherein the fault latch 104 comprises transistors (Q3 and Q4), resistors (R8, R9, R10, R16), capacitor C3, and diode D2.

6. The blinker control circuit 100 as claimed in claim 1, wherein the output driver 102 is provided with a current limiter, wherein the output driver 102 with current limiter comprises transistors (Q5 and Q7) to switch on and off at base frequency, resistors (R11, R17, R14) and diode D1.

7. The blinker control circuit 100 as claimed in claim 1, wherein the fault detector 103 comprises resistor R13 and transistor Q6.

8. The blinker control circuit 100 as claimed in claim 1, wherein the double frequency of the astable multivibrator 101 is ranging from 3 to 3.7 Hz.

9. The blinker control circuit 100 as claimed in claim 1, wherein the output driver 102 drives a load selected at least one from a group of a rear and/or front lamp of a vehicle, a plurality of light emitting diodes (LEDs), Bulb, a turning light of a vehicle, a direction lamp of a vehicle.

10. A method 400 for facilitating a blinker control circuit, comprising:
configiuring an astable multivibrator 101 to oscillate at a base frequency in order to turn ON/OFF of a blinker;
receiving, by an output driver 102, ON/OFF signal from the astable multivibrator 101, wherein the ON/OFF signal controls the turning ON/OFF of the blinker based upon the oscillation of the astable multivibrator 101 at a base frequency;
enabling, by the output driver 102, a fault latch 104 based upon an output signal received from the output driver 102;
checking, by a fault detector 103, a current in the output driver 102, wherein the fault detector 103 is electronically coupled with the output driver 102, wherein when the current in the output driver is above a minimum threshold, the fault detector 103 generates a fault clear signal thereby disabling the fault latch 104; and
receiving, by the frequency doubler 105, an enable signal or a disable signal from the fault latch 104 depending upon the enabling or disabling of the fault latch 104 respectively, and wherein the enable signal activates the frequency doubler 105 to switch the astable multivibrator 101 to oscillate at the double frequency of the base frequency, and wherein the disable signal enables the astable multivibrator 101 to continue to oscillate at the base frequency.

11. The method 400 as claimed in claim 10, wherein the astable multivibrator 101 is oscillating at the base frequency ranging from 1.5 to 1.83Hz.

12. The method 400 as claimed in claim 10, wherein the double frequency of the astable multivibrator 101 is ranging from 3 to 3.7 Hz.

Dated this 20th Day of August 2020

Priyank Gupta
Agent for the Applicant
IN/PA- 1454

, Description: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 BLINKER CONTROL CIRCUIT AND AN OPERATING METHOD THEREOF

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.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application does not claim priority from any other patent application.
TECHNICAL FIELD
The present subject matter described herein, in general, relates to the field of electronic control circuit. More particularly, the invention relates to a blinker control circuit and a method thereof.
BACKGROUND
The automotive lighting system comprising lighting and signalling devices are mounted on a vehicle for assisting a driver while driving. Further, these automotive lighting systems provide distinctive lighting to alert driver in case of emergency or failures. More specifically, such lighting systems include lamps, bulbs, LEDs, reflectors to provide indication of presence, position, direction of travel, change in direction or deacceleration of the vehicle to other drivers and pedestrians around them. Such lamps blink or flash at certain speed based upon the functionality. Typically, “direction indicator lamps” or “turn indicator lamps” are referred as blinkers or flashers. Such lamps are mounted at left and right corners of the front and rear sides of the vehicle.
As per the International UN regulations, the turn signals are configured to blink on and off, or "flash", at a steady rate of between 60 and 120 Blinks Per Minute (BPM) (1–2 Hz). Conventionally, this blinking control is achieved using a thermal flasher relay. The thermal flasher relay is configured to use a thermostat principle to achieve flashing sequence wherein the amount of heat generated in the thermostat decides the frequency of blinking. In case of bulb failure, the current flowing in thermostat falls and cools down the thermostat which doubles the frequency of blinking. It must be noted herein that the switching of the blinkers at double the frequency is indicative of failure of the bulb/lamp in the blinker device which can be further indicated to the driver on the display cluster of the vehicle.
Now a days, the light emitting diodes (LEDs) are replacing the conventional incandescent bulbs used in the automotive lighting systems. It is observed that LEDs are configured to draw only fraction of current as compared to incandescent bulbs. Therefore, thermostat principle is no longer suitable due to insufficient heat generation for operation of thermal flasher relay. Further, in case failure of LED, the difference in the current flowing in the thermostat is also small. Therefore, it is difficult for the thermostat to detect difference between the currents.
Therefore, there is long standing need for a blinker control circuit that alleviates the aforementioned technical challenges/drawbacks and yet provide a simple and cost effective solution.

SUMMARY

This summary is provided to introduce the concepts related to a blinker control circuit and the concepts are further described in the detail description. This summary is not intended to identify essential features of the claimed subject matter nor it is intended to use in determining or limiting the scope of claimed subject matter.

In one implementation, the present subject matter describes a blinker control circuit. The blinker control circuit may comprise an astable multivibrator, an output driver, a fault latch, a fault detector, and a frequency doubler. The astable multivibrator may be configured for oscillating at a base frequency in order to turn ON/OFF of a blinker. The output driver may be configured for receiving ON/OFF signal from the astable multivibrator. The ON/OFF signal may control the turning ON/OFF of the blinker based upon the oscillation of the astable multivibrator at a base frequency. The fault latch may be configured to be enabled based upon an output signal received from the output driver. The fault detector, electronically coupled with the output driver, may be configured for checking a current in the output driver. When the current in the output driver is above a minimum threshold, the fault detector may generate a fault clear signal thereby disabling the fault latch. The frequency doubler may be configured to receive an enable signal or a disable signal from the fault latch depending upon the enabling or disabling of the fault latch, respectively. The enable signal may activate the frequency doubler to switch the astable multivibrator to oscillate at the double frequency of the base frequency. The disable signal may enable the astable multivibrator to continue to oscillate at the base frequency.

In another implementation, the present subject matter describes a method for operating a blinker control circuit. The method may comprise a step of configuring an astable multivibrator to oscillate at a base frequency in order to turn ON/OFF of a blinker. The method may further comprise a step of receiving, by an output driver, ON/OFF signal from the astable multivibrator, wherein the ON/OFF signal controls the turning ON/OFF of the blinker based upon the oscillation of the astable multivibrator at a base frequency. The method may further comprise a step of enabling a fault latch based upon an output signal received from the output driver. The method may comprise a step of checking, by a fault detector, a current in the output driver, wherein the fault detector electronically coupled with the output driver. When the current in the output driver is above a minimum threshold, the fault detector generates a fault clear signal thereby disabling the fault latch. The method may comprise a step of receiving, by the frequency doubler, an enable signal or a disable signal from the fault latch depending upon the enabling or disabling of the fault latch respectively, and wherein the enable signal activates the frequency doubler to switch the astable multivibrator to oscillate at the double frequency of the base frequency. The disable signal may enable the astable multivibrator to continue to oscillate at the base frequency.

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 a blinker control circuit, in accordance with an embodiment of a present subject matter.

Figure 2 illustrates a circuit diagram 200 of the blinker control circuit, in accordance with an embodiment of a present subject matter.

Figure 3A-3H illustrates waveform signals at output of various circuity components of the blinker control circuit, in accordance with an embodiment of a present subject matter.

Figure 4 illustrates a stepwise flowchart of a method 400 for operating the blinker control circuit, in accordance with an embodiment of a 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.

Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. 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 now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.

Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein. Though the below description, in conjunction with the drawings, has been described using transistor in the blinker control circuit, however, the present disclosure is not necessarily limited to the use of transistor in the blinker control circuit as described below.

Figure 1 illustrates, a block diagram of a blinker control circuit 100, in accordance with an embodiment of a present subject matter. The blinker control circuit may comprise an astable multivibrator 101, an output driver 102, a fault detector 103, a fault latch 104, and a frequency doubler 105. The astable multivibrator 101 may configured to oscillate at a base frequency in order to turn ON/OFF of a blinker. In one embodiment, the astable multivibrator may be configured to oscillate at the base frequency ranging from 1.5 to 1.83Hz. The output driver 102 may be configured for receiving ON/OFF signal from the astable multivibrator 101. In on embodiment, the ON/OFF signal may control the turning ON/OFF of the blinker based upon the oscillation of the astable multivibrator 101 at a base frequency. In one embodiment, the output driver 102 may drive a load selected at least one from a group comprising, but not limited to, a rear and/or front lamp of a vehicle, a plurality of light emitting diodes (LEDs), Bulb, a turning light of a vehicle, a direction lamp of a vehicle. It is to be noted by a person skilled in the art that the examples of load described herein is for explanatory purpose and is not necessary to limit the scope of the present claimed subject matter. The fault latch 104 may be configured to be enabled based upon an output signal received from the output driver 102. The fault detector 103, electronically coupled with the output driver, may be configured for checking a current in the output driver. In one scenario, when the current in the output driver 102 is above a minimum threshold, the fault detector 103 may be configured to generate a fault clear signal thereby disabling the fault latch 104. In another scenario, when the current in the output driver 102 is below the minimum threshold, the fault latch 104 may remain enabled. The frequency doubler 105 may be configured to receive an enable signal or a disable signal from the fault latch 104 depending upon the enabling or disabling of the fault latch 104, respectively. The enable signal may configured to activate the frequency doubler 105 to switch the astable multivibrator 101 to oscillate at the double frequency of the base frequency. Alternatively, the disable signal enables the astable multivibrator 101 continues to oscillate at the base frequency.

Now referring to Figure 2, a circuit diagram 200 of the blinker control circuit is illustrated in accordance with an embodiment of the present subject matter. The circuit diagram 200 of the blinker control circuit illustrates electrical connection between the astable multivibrator 101, the output driver 102, the fault detector 103, the fault latch 104, and the frequency doubler 105. A battery power is connected to the astable multivibrator 101 and the output driver 102.

As shown in figure, 2, the astable multivibrator 101 may comprise transistors (Q1 and Q2) arranged in parallel, capacitors (C1, C2), and resistors R1, R2, R3, R4. The resistors R1 and R4 may configured to act as load resistors. The R2C1 and R3C2 may be configured to change the time constant of the astable multivibrator 101. It is to be noted by a person skilled in the art that the circuit of the astable multivibrator 101 is merely shown for explanatory/description purpose and is not necessary to limit the scope of the present claimed subject matter. The person skilled in the art can easily realize and appreciate that the exemplary circuit shown can be replaced with other circuits incorporating the similar functionality but without deviating from the scope of the present claimed subject matter.

Further, as shown in figure 2, the frequency doubler 105 may comprise resistors (R6 and R7). The resistors R6 and R7 may be arranged parallel to resistors R2 and R3 of the astable multivibrator respectively, when R6 and R7 are switched on in the circuit. The resistors R2 and R3 may configured to change the time constant of the astable multivibrator 101 to double the base frequency. It is to be noted by a person skilled in the art that the exemplary circuit of the frequency doubler 105 is merely shown for explanatory/description purpose and is not necessary to limit the scope of the present claimed subject matter. The person skilled in the art can easily realize and appreciate that the exemplary circuit shown can be replaced with other circuits incorporating the similar functionality but without deviating from the scope of the present claimed subject matter.

Further, as shown in figure 2, the fault latch 104 may comprise transistors (Q3 and Q4), resistors (R8, R9, R10, R16), capacitor C3, and diode D2. The output driver 102 may be provided with a current limiter. The output driver 102 with current limiter may comprise transistors (Q5 and Q7) to switch on and off at base frequency, resistors (R11, R17, R14) and diode D1. The fault detector 103 may comprise resistor R13 and transistor Q6. It is to be noted by a person skilled in the art that the exemplary circuits of the fault latch 104, the output driver 102 frequency, and the fault detector 103 are merely shown for explanatory/description purpose and is not necessary to limit the scope of the present claimed subject matter. The person skilled in the art can easily realize and appreciate that the exemplary circuits shown can be replaced with other circuits incorporating the similar functionality but without deviating from the scope of the present claimed subject matter.
Having described the aforementioned exemplary circuits of various components of the blinker control circuit, the working of these components will be described in detail hereinafter referring to Figure 2 and 3A-3H as below.

In a first case scenario, when the rear and front blinker are working normally, the astable multivibrator 101 may be configured to oscillate at a base frequency to turn ON/OFF of the blinker, when the battery power is connected to the astable multivibrator 101. In one embodiment, the base frequency may range from 1.5Hz to 1.83 Hz. The blinker may be a rear and a front blinker. The output driver 102 may be configured for receiving ON/OFF signal from the astable multivibrator 101. Now referring to figure 3A, output waveform of the output driver 102 at the base frequency of 1.7 Hz during normal operation of the blinker is illustrated, in accordance with one exemplary embodiment of the present subject matter. As shown, the output of the output driver 102 is a square wave which oscillates between “high” and “low” and generates continuous ON/OFF output signal.

Now again referring to figure 2, the transistor (Q5 and Q7) of the output driver 102 may be configured to switch ON and OFF at the base frequency, after receiving ON/OFF signal from the astable multivibrator 101. The output of the transistor Q5 may be connected to the fault latch 104. When transistor Q5 is switched ON, a trigger pulse is generated by capacitor C3, resistor R16 and diode D2 of the fault latch 104. The trigger pulse may be transmitted to the transistor Q4 in order to activate the fault latch 104. Further, the transistor Q4 may activate the transistor Q3. It is to be noted herein that when the rear and the front blinker are working normally, the current flowing through resistor R14 is sufficient to switch on transistor Q6 of the fault detector 103. The resistor R14 may be configured to act as a sense resistor in the output driver 102. When the current flows through resistor R14, then there is a voltage drop across the resistor R14 as can be seen from figure 3B. In one embodiment, a voltage drop of 1.1 V is observed when voltage is passed through R14. Due to the occurrence of the voltage drop at the resistor R14 during ON state, the “high” state of output driver 102 is observed slightly less than 12V as can be seen from figure 3A. The transistor Q6 of the fault detector 103 may be configured to generate a fault clear signal, when current received from resistor R14 is above the minimum threshold.

Now referring to Fig.3C, it is noted that initially the output of the transistor Q6 tends to drop down and again rises quickly. Further, the fault clear signal is configured to switch off transistor Q3 and thereby disables the fault latch 104. As a result, the fault latch 103 enables and again disables quickly. The frequency doubler 105 may get a momentary signal from the fault-latch 103 to double the base frequency of the astable multivibrator 101. However, before the momentary signal can impact the base frequency of the astable multivibrator 101, the fault-latch 104 is cleared and the signal is withdrawn.

Now referring to figure 3D, waveform of an input signal of the frequency doubler 105 is illustrated. It is noted that the input signal of the frequency doubler 104 starts with 0V with a voltage spike pulse, where transistor Q3 starts momentarily. When the transistor Q6 is turned ON, it generates the fault clear signal and turns off the transistor Q3 and thereby disables the fault latch 104. Therefore, the input signal waveform of the frequency doubler shows voltage spike pulse followed by negative pulse. Therefore, in this exemplary embodiment, the astable multivibrator 101 continues to oscillate at the base frequency 1. 7Hz for the next cycle.

In a second case scenario, when either the front or the rear blinker fails, or gets disconnected, the current flowing through resistor R14 reduces due to less voltage drop as can be seen from figure 3E. Due to reduced current, it becomes insufficient to switch on transistor Q6 and thereby enabling the fault latch. Referring to figure 3F, in this exemplary embodiment, it is noted that the output waveform of the transistor Q6 is a constant output waveform due to base to emitter drop of 0.7V from the 12V with only slight variation occurred due to pulse transition. Further, when transistor Q5 is switched on, the trigger pulse generated by capacitor C3, resistor R16 and diode D2 of the fault latch 104 may be configured to switch on transistor (Q4, Q3) and resistors (R8, R9 and R10). The fault latch 104 may further enable resistors (R6, R7) of the frequency doubler 105. The input of the frequency doubler is shown in figure 3G. The resistors (R6, R7) of the frequency doubler 105 appear parallel to resistors R2 and R3 of the astable multivibrator respectively, when R6 and R7 are switched on in the circuit. The resistors R2 and R3 may configured to change the time constant of the astable multivibrator 101 to double the base frequency. The astable multivibrator 101 continues to oscillate at the double frequency and turns ON/OFF of the blinker at the double frequency, until the current flowing through R14 rises to a normal level. The output of the astable multivibrator is given to the output driver of the blinker. Figure 3H depicts the output signal waveform of the output driver 102 at double frequency of the base frequency i.e. 3.5 Hz during faulty operation of the blinker is illustrated.

Now referring to Figure 4, a stepwise flowchart of a method 400 for operating the blinker control circuit is depicted in accordance with an embodiment of a present subject matter.

At step 401, the astable multivibrator 101 may be configured to oscillate at a base frequency in order to turn ON/OFF of a blinker.

At step 402, the output driver 102 may be configured to receive ON/OFF signal from the astable multivibrator. The ON/OFF signal may control the turning ON/OFF of the blinker based upon the oscillation of the astable multivibrator at a base frequency.

At step 403, the output driver 102 may be configured to enable the fault latch 104 based upon the output signal received from the output driver 102.

At step 404, the fault detector 103 may be configured to check the current in the output driver 102. The fault detector 103 may be electronically coupled with the output driver 102. When the current in the output driver 102 is above a minimum threshold, the fault detector 103 may generate the fault clear signal thereby disabling the fault latch 104.

At step 405, the frequency doubler 105 may be configured to receive the enable signal or the disable signal from the fault latch 104 depending upon the enabling or disabling of the fault latch 104, respectively. The enable signal may configured to activate the frequency doubler 105 to switch the astable multivibrator 101 to oscillate at the double frequency of the base frequency. On the contrary, the disable signal enables the astable multivibrator 101 to continue to oscillate at the base frequency.

Although implementations for the blinker control circuit 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 blinker control circuit.