A control circuit and implementation method for a vehicle light controller to achieve limp home

Abstract

The present invention discloses a control circuit for implementing limp home mode in a headlight controller, comprising a linear voltage regulator module and a constant voltage module. The enable pins EN of the linear voltage regulator module and the constant voltage module are respectively connected to the headlight control signal terminal, the input terminals of the linear voltage regulator module and the constant voltage module are respectively connected to the headlight power supply, the output terminal of the linear voltage regulator module is respectively connected to the MCU and the limp home mode control circuit, the limp home mode control circuit is further respectively connected to the constant voltage module, the MCU, and the constant current module, and the output terminal of the constant current module is connected to the headlight control terminal. The present invention also discloses a method for implementing the control circuit for implementing limp home mode in a headlight controller. The present invention utilizes only a single-channel constant voltage module and a single-channel constant current module in conjunction with the limp home mode control circuit. Even after the MCU fails, the normal operation of the constant current module can still be ensured, thereby ensuring the normal lighting of the headlights and achieving the limp home mode function.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle light controllers, and in particular relates to a control circuit and an implementation method thereof for a vehicle light controller to realize limp home. Background Art

[0002] The LED constant-current drive solution for headlights uses a boost constant-voltage chip and a buck constant-current chip. To achieve platform-based headlight LED drive solutions, the boost and buck chips in existing solutions are integrated two-way or three-way drivers with SPI communication capabilities. The microcontroller (MCU) can set the boost voltage and buck current through SPI. The chip also has a limphome function, which ensures the continuous output of basic lighting functions when the MCU fails.

[0003] However, the existing domestic automotive-grade Boost constant voltage chips and Buck constant current chips are only single-channel integrated, and neither have SPI communication function nor limp home function. They can only realize simple lighting function, cannot be platformized, and cannot achieve complete functional replacement. Summary of the Invention

[0004] The present invention aims to provide a control circuit for a headlight controller to achieve limp home, so as to solve the problems mentioned in the above background technology. The present invention provides a control circuit for a headlight controller to achieve limp home, which has the characteristics of platformization, constant current and limp home function.

[0005] Another object of the present invention is to provide a method for implementing a control circuit of a vehicle light controller to achieve limp home operation.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a car light controller realizes a control circuit of limp home, comprising a linear voltage regulator module and a constant voltage module, wherein the enable pins EN of the linear voltage regulator module and the constant voltage module are respectively connected to the car light control signal end, the input ends of the linear voltage regulator module and the constant voltage module are respectively connected to the car light power supply, the output end of the linear voltage regulator module is respectively connected to the MCU and the limp home control circuit, the limp home control circuit is also respectively connected to the constant voltage module, the MCU and the constant current module, and the output end of the constant current module is connected to the car light control end.

[0007] In order to set the output current, the output current is changed by changing the resistance value of the sampling resistor R2. Furthermore, the IA DJ pins of the constant current module are connected to one end of the resistor R1 and the resistor R2 respectively, the other end of the resistor R2 is connected to the ground end, and the other end of the resistor R1 is connected to the output end of the linear voltage regulator module.

[0008] In order to form a voltage divider regulation circuit through resistors R3 and R4 to achieve regulation of the VBoost voltage value, the limp home control circuit further includes a capacitor C2, one end of the capacitor C2 is connected to the PWM pin of the MCU, the other end of the capacitor C2 is connected to the positive end of the diode D4, the negative end of the diode D4 is connected to one end of the resistor R5, the other end of the resistor R5 is respectively connected to one end of the capacitor C1 and the resistor R6, the other end of the resistor R6 is respectively connected to the resistor R3, the resistor R4 and the FB pin of the constant voltage module, the other ends of the capacitor C1 and the resistor R4 are connected to the ground end, and the other end of the resistor R3 is the VBoost voltage regulation end.

[0009] In order to control the transistor Q1 to be turned on by the PWM signal when the MCU is working normally, thereby disconnecting the transistors Q2, Q4 and Q3, thereby avoiding affecting the voltage divider regulation circuit, the limp home control circuit further includes a diode D5, the positive terminal of the diode D5 is connected to the positive terminal of the diode D4, the negative terminal of the diode D5 is connected to the resistor R7, the other end of the resistor R7 is respectively connected to one end of the capacitor C3 and the base of the transistor Q1, and the collector of the transistor Q1 is respectively connected to The base of the transistor Q2 is connected to one end of the resistor R8, the collector of the transistor Q2 is connected to one end of the resistor R9 and the resistor R12 respectively, the other end of the resistor R9 is connected to the base of the transistor Q3, the other end of the resistor R12 is connected to the base of the transistor Q4, the other end of the resistor R8, the emitter of the transistor Q3 and the emitter of the transistor Q4 are respectively connected to the output end of the linear voltage regulator module, and the other end of the capacitor C3, the emitter of the transistor Q1 and the emitter of the transistor Q2 are respectively connected to the ground end.

[0010] In order to enable the resistor R10 and the VCC voltage to participate in the voltage divider adjustment circuit composed of the resistors R3 and R4 when the MCU fails, so that the VBoost voltage is fixed to the required voltage value, further, the collector of the transistor Q3 is connected to one end of the resistor R10, and the other end of the resistor R10 is connected to one end of the resistor R3 and the resistor R4.

[0011] In order to make the car lights light up normally when the MCU fails, VCC is connected to the enable pin EN of the constant current module through the transistor Q4 and the resistor R13. Furthermore, the collector of the transistor Q4 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the EN end of the constant current module.

[0012] In order for the MCU to work normally, the MCU sends an EN Buck signal, which is transmitted to the enable pin EN of the constant current module after passing through the diode D6 and the resistor R11, so that the constant current module can work at a constant current. Furthermore, the limp home control circuit also includes a diode D6, the positive terminal of the diode D6 is connected to the EN Buck terminal of the MCU, the negative terminal of the diode D6 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the EN terminal of the constant current module.

[0013] Furthermore, in the present invention, a method for implementing a control circuit of a vehicle light controller to realize limp home operation comprises the following steps:

[0014] (1) When the MCU is operating normally, the MCU sends a PWM signal. The PWM signal is rectified into an analog signal after passing through a first-order filter circuit composed of a diode D4, a resistor R5, and a capacitor C1. The analog signal then passes through a voltage divider circuit composed of a resistor R6 and resistors R3 and R4 to adjust the voltage value of VBoost.

[0015] (2) At the same time, after the PWM signal passes through the first-order filter circuit composed of diode D5, resistor R7 and capacitor C3, transistor Q1 is turned on, transistor Q2 and transistor Q4 are turned off, and transistor Q3 is turned off, avoiding the influence on the voltage divider regulation circuit;

[0016] (3) At the same time, the MCU sends the EN Buck signal, which is transmitted to the enable pin EN of the constant current module through the diode D6 and the resistor R11, so that the constant current module can work in constant current;

[0017] (4) When the MCU fails, the MCU cannot send PWM signals, and the DC signal cannot pass through capacitor C2, causing transistor Q1 to be disconnected. The VCC voltage of the linear voltage regulator module controls transistor Q2 to be turned on through resistor R8, thereby turning on transistors Q3 and Q4. The resistor R10 and the VCC voltage participate in the voltage divider adjustment circuit composed of resistors R3 and R4, so that the VBoost voltage is fixed to the required voltage value;

[0018] (5) At the same time, VCC passes through transistor Q4 and resistor R13 to the enable pin EN of the constant current module, so that the car lights are normally lit.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention only uses a single-channel constant voltage module and a single-channel constant current module in conjunction with the limp home control circuit. After the MCU fails, the normal operation of the constant current module can still be guaranteed, thereby ensuring the normal lighting of the car lights and realizing the limp home function.

[0021] 2. The present invention sets the output current by the voltage divider value of the sampling resistor R1 and the sampling resistor R2, and changes the output current by changing the resistance value of the sampling resistor R2;

[0022] 3. The present invention forms a voltage divider adjustment circuit by resistors R3 and R4 to adjust the VBoost voltage value;

[0023] 4. When the MCU is working normally, the present invention controls the transistor Q1 to be turned on through the PWM signal, thereby disconnecting the transistors Q2, Q4 and Q3, thereby avoiding affecting the voltage divider regulation circuit;

[0024] 5. When the MCU fails, the present invention enables the resistor R10 and the VCC voltage to participate in the voltage divider adjustment circuit composed of the resistor R3 and the resistor R4, so that the VBoost voltage is fixed to the required voltage value;

[0025] 6. In the present invention, when the MCU fails, VCC passes through the transistor Q4 and the resistor R13 to the enable pin EN of the constant current module, so that the car lights are normally lit;

[0026] 7. In the present invention, when the MCU is working normally, the MCU sends an EN Buck signal, which is transmitted to the enable pin EN of the constant current module through the diode D6 and the resistor R11, so that the constant current module can work in constant current. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a principle block diagram of the present invention;

[0028] Figure 2 is a circuit diagram of a limp home control circuit of the present invention; DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Example 1

[0031] See also Figure 1-2The present invention provides the following technical solutions: a control circuit for a headlight controller to implement limp home control, comprising a linear voltage regulator module and a constant voltage module, wherein the enable pins EN of the linear voltage regulator module and the constant voltage module are respectively connected to the headlight control signal terminal, the input terminals of the linear voltage regulator module and the constant voltage module are respectively connected to the headlight power supply, the output terminal of the linear voltage regulator module is respectively connected to the MCU and the limp home control circuit, the limp home control circuit is further respectively connected to the constant voltage module, the MCU and the constant current module, and the output terminal of the constant current module is connected to the headlight control terminal.

[0032] By adopting the above technical solution, the present invention only cooperates with the limp home control circuit through a single-channel constant voltage module and a single-channel constant current module. After the MCU fails, the normal operation of the constant current module can still be guaranteed, thereby ensuring the normal lighting of the car lights and realizing the limp home function.

[0033] Specifically, the IA DJ pins of the constant current module are connected to one end of the resistor R1 and the resistor R2 respectively, the other end of the resistor R2 is connected to the ground end, and the other end of the resistor R1 is connected to the output end of the linear voltage regulator module.

[0034] By adopting the above technical solution, the present invention sets the output current by the voltage division value of the sampling resistor R1 and the sampling resistor R2, and changes the output current by changing the resistance value of the sampling resistor R2.

[0035] Specifically, the limp home control circuit includes a capacitor C2, one end of the capacitor C2 is connected to the PWM pin of the MCU, the other end of the capacitor C2 is connected to the positive end of the diode D4, the negative end of the diode D4 is connected to one end of the resistor R5, the other end of the resistor R5 is connected to one end of the capacitor C1 and the resistor R6 respectively, the other end of the resistor R6 is connected to the resistor R3, the resistor R4 and the FB pin of the constant voltage module respectively, the other ends of the capacitor C1 and the resistor R4 are connected to the ground end, and the other end of the resistor R3 is the VBoost voltage regulation end.

[0036] By adopting the above technical solution, the present invention forms a voltage-dividing adjustment circuit through the resistor R3 and the resistor R4 to achieve the adjustment of the VBoost voltage value.

[0037] Specifically, the limp home control circuit also includes a diode D5, the positive terminal of the diode D5 is connected to the positive terminal of the diode D4, the negative terminal of the diode D5 is connected to the resistor R7, the other end of the resistor R7 is respectively connected to one end of the capacitor C3 and the base of the transistor Q1, the collector of the transistor Q1 is respectively connected to the base of the transistor Q2 and one end of the resistor R8, the collector of the transistor Q2 is respectively connected to one end of the resistor R9 and one end of the resistor R12, the other end of the resistor R9 is connected to the base of the transistor Q3, the other end of the resistor R12 is connected to the base of the transistor Q4, the other end of the resistor R8, the emitter of the transistor Q3, and the emitter of the transistor Q4 are respectively connected to the output end of the linear voltage regulator module, and the other end of the capacitor C3, the emitter of the transistor Q1, and the emitter of the transistor Q2 are respectively connected to the ground end.

[0038] By adopting the above technical solution, when the MCU is working normally, the present invention controls the transistor Q1 to be turned on through the PWM signal, thereby disconnecting the transistors Q2, Q4 and Q3, thereby avoiding affecting the voltage divider regulation circuit.

[0039] Example 2

[0040] The difference between this embodiment and the first embodiment is that: specifically, the collector of the transistor Q3 is connected to one end of the resistor R10 , and the other end of the resistor R10 is connected to one end of the resistor R3 and the resistor R4 .

[0041] By adopting the above technical solution, when the MCU fails, the present invention enables the resistor R10 and the VCC voltage to participate in the voltage divider adjustment circuit composed of the resistor R3 and the resistor R4, so that the VBoost voltage is fixed to the required voltage value.

[0042] Example 3

[0043] The difference between this embodiment and the first embodiment is that: specifically, the collector of the transistor Q4 is connected to one end of the resistor R13, and the other end of the resistor R13 is connected to the EN end of the constant current module.

[0044] By adopting the above technical solution, when the MCU fails, the present invention transmits VCC to the enable pin EN of the constant current module through the transistor Q4 and the resistor R13, so that the car lights are normally lit.

[0045] Example 4

[0046] This embodiment differs from Embodiment 1 in that: specifically, the limp home control circuit further includes a diode D6, the positive terminal of the diode D6 is connected to the EN Buck terminal of the MCU, the negative terminal of the diode D6 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the EN terminal of the constant current module.

[0047] By adopting the above technical solution, when the MCU is working normally, the MCU sends an EN Buck signal, which is transmitted to the enable pin EN of the constant current module through the diode D6 and the resistor R11, so that the constant current module works at a constant current.

[0048] Example 5

[0049] This embodiment differs from the first embodiment in that the method for implementing the control circuit of the vehicle light controller for limp home according to the present invention comprises the following steps:

[0050] (1) When the MCU is operating normally, the MCU sends a PWM signal. The PWM signal is rectified into an analog signal after passing through a first-order filter circuit composed of a diode D4, a resistor R5, and a capacitor C1. The analog signal then passes through a voltage divider circuit composed of a resistor R6 and resistors R3 and R4 to adjust the voltage value of VBoost.

[0051] (2) At the same time, after the PWM signal passes through the first-order filter circuit composed of diode D5, resistor R7 and capacitor C3, transistor Q1 is turned on, transistor Q2 and transistor Q4 are turned off, and transistor Q3 is turned off, avoiding the influence on the voltage divider regulation circuit;

[0052] (3) At the same time, the MCU sends the EN Buck signal, which is transmitted to the enable pin EN of the constant current module through the diode D6 and the resistor R11, so that the constant current module can work in constant current;

[0053] (4) When the MCU fails, the MCU cannot send PWM signals, and the DC signal cannot pass through capacitor C2, causing transistor Q1 to be disconnected. The VCC voltage of the linear voltage regulator module controls transistor Q2 to be turned on through resistor R8, thereby turning on transistors Q3 and Q4. The resistor R10 and the VCC voltage participate in the voltage divider adjustment circuit composed of resistors R3 and R4, so that the VBoost voltage is fixed to the required voltage value;

[0054] (5) At the same time, VCC passes through transistor Q4 and resistor R13 to the enable pin EN of the constant current module, so that the car lights are normally lit.

[0055] In summary, the present invention only cooperates with the limp home control circuit by using a single constant voltage module and a single constant current module. After the MCU fails, the normal operation of the constant current module can still be guaranteed, thereby ensuring the normal lighting of the car lights and realizing the limp home function. The present invention sets the output current by the voltage divider value of the sampling resistor R1 and the sampling resistor R2, and changes the output current by changing the resistance value of the sampling resistor R2. The present invention forms a voltage divider adjustment circuit by the resistor R3 and the resistor R4 to adjust the VBoost voltage value. When the MCU is working normally, the present invention , the transistor Q1 is controlled to be turned on through the PWM signal, thereby disconnecting the transistor Q2, the transistor Q4 and the transistor Q3, thereby avoiding affecting the voltage-dividing regulation circuit; when the MCU fails, the resistor R10 and the VCC voltage participate in the voltage-dividing regulation circuit composed of the resistor R3 and the resistor R4, so that the VBoost voltage is fixed to the required voltage value; when the MCU fails, the VCC is transmitted to the enable pin EN of the constant current module through the transistor Q4 and the resistor R13, so that the car lights are normally lit; when the MCU works normally, the MCU sends an EN Buck signal, which is transmitted to the enable pin EN of the constant current module through the diode D6 and the resistor R11, so that the constant current module operates at a constant current.

[0056] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A control circuit for a vehicle light controller to achieve limp home operation, characterized in that: It includes a linear voltage regulator module and a constant voltage module, wherein the enable pins EN of the linear voltage regulator module and the constant voltage module are respectively connected to the headlight control signal terminal, the input terminals of the linear voltage regulator module and the constant voltage module are respectively connected to the headlight power supply, the output terminal of the linear voltage regulator module is respectively connected to the MCU and the limp home control circuit, the limp home control circuit is further respectively connected to the constant voltage module, the MCU and the constant current module, and the output terminal of the constant current module is connected to the headlight control terminal; The IA DJ pins of the constant current module are connected to one end of the resistor R1 and one end of the resistor R2 respectively, the other end of the resistor R2 is connected to the ground terminal, and the other end of the resistor R1 is connected to the output terminal of the linear voltage regulator module; The limp home control circuit includes capacitor C2, one end of which is connected to the PWM pin of the MCU, the other end of which is connected to the positive terminal of diode D4, the negative terminal of diode D4 is connected to one end of resistor R5, the other end of resistor R5 is connected to one end of capacitor C1 and resistor R6 respectively, the other end of resistor R6 is connected to resistor R3, resistor R4 and the FB pin of the constant voltage module respectively, the other ends of capacitor C1 and resistor R4 are connected to ground, and the other end of resistor R3 is the VBoost voltage regulation terminal; The limp home control circuit also includes a diode D5, a positive terminal of diode D5 connected to the positive terminal of diode D4, a negative terminal of diode D5 connected to resistor R7, the other end of resistor R7 respectively connected to one end of capacitor C3 and the base of transistor Q1, the collector of transistor Q1 respectively connected to the base of transistor Q2 and one end of resistor R8, the collector of transistor Q2 respectively connected to one end of resistor R9 and one end of resistor R12, the other end of resistor R9 connected to the base of transistor Q3, the other end of resistor R12 connected to the base of transistor Q4, the other end of resistor R8, the emitter of transistor Q3, and the emitter of transistor Q4 respectively connected to the output end of the linear voltage regulator module, and the other end of capacitor C3, the emitter of transistor Q1, and the emitter of transistor Q2 respectively connected to the ground end; The collector of transistor Q3 is connected to one end of resistor R10, and the other end of resistor R10 is connected to one end of resistor R3 and resistor R4; The collector of the transistor Q4 is connected to one end of the resistor R13 , and the other end of the resistor R13 is connected to the EN end of the constant current module.

2. The control circuit for realizing limp home driving by a headlight controller according to claim 1, characterized in that: The limp home control circuit further includes a diode D6, the positive terminal of the diode D6 is connected to the EN Buck terminal of the MCU, the negative terminal of the diode D6 is connected to one end of the resistor R11, and the other end of the resistor R11 is connected to the EN terminal of the constant current module.

3. The method for implementing a control circuit for a vehicle light controller to achieve limp home according to claim 2, characterized in that: The following steps are involved: (1) When the MCU is operating normally, the MCU sends a PWM signal. The PWM signal is rectified into an analog signal after passing through a first-order filter circuit composed of a diode D4, a resistor R5, and a capacitor C1. The analog signal then passes through a voltage divider circuit composed of a resistor R6 and resistors R3 and R4 to adjust the voltage value of VBoost. (2) At the same time, after the PWM signal passes through the first-order filter circuit composed of diode D5, resistor R7 and capacitor C3, transistor Q1 is turned on, transistor Q2 and transistor Q4 are turned off, and transistor Q3 is turned off, avoiding the influence on the voltage divider regulation circuit; (3) At the same time, the MCU sends the EN Buck signal, which is transmitted to the enable pin EN of the constant current module through the diode D6 and the resistor R11, so that the constant current module can work in constant current; (4) When the MCU fails, the MCU cannot send PWM signals, and the DC signal cannot pass through capacitor C2, causing transistor Q1 to be disconnected. The VCC voltage of the linear voltage regulator module controls transistor Q2 to be turned on through resistor R8, thereby turning on transistors Q3 and Q4. The resistor R10 and the VCC voltage participate in the voltage divider adjustment circuit composed of resistors R3 and R4, so that the VBoost voltage is fixed to the required voltage value; (5) At the same time, VCC passes through transistor Q4 and resistor R13 to the enable pin EN of the constant current module, so that the car lights are normally lit.

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