Vehicle lamp control system with self-adaptive current change and control method of vehicle lamp control system

Abstract

The invention relates to the technical field of vehicle lamp control, in particular to a vehicle lamp control system with self-adaptive current change and a control method thereof. The vehicle lamp control system with the current changing adaptively comprises a voltage detection unit used for detecting the power voltage of a vehicle body, and a low-dropout linear voltage stabilization unit used for reducing the power voltage and providing stable voltage for a microcontroller unit; the signal detection unit is used for detecting a vehicle body input signal and transmitting the filtered signal to the microcontroller unit; the automobile lamp driving unit is used for controlling on and off of an LED of an automobile lamp and feeding back fault information to the microcontroller unit; the step-up and step-down conversion unit is used for providing stable voltage for the vehicle lamp driving unit; and the microcontroller unit is used for judging whether a current reducing strategy is carried out or not and / or controlling the vehicle lamp driving unit to execute a lighting action according to the received data and signals. The automobile lamp in a low-voltage state can be kept lighted, and components in the automobile lamp are prevented from being damaged by large current.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle light control, and in particular to a vehicle light control system with adaptive current change and a control method thereof. Background Art

[0002] The headlight control system plays a vital role in improving driving safety and driving experience. Traditional headlight control systems usually use a fixed current drive design to ensure the brightness and performance of the headlights. However, in actual applications, the current demand of the headlights will fluctuate due to changes in the working environment, vehicle status, and external conditions. Under low-voltage operation or different temperature changes, the fixed current design will cause components to heat up, which will shorten the life of the headlights and cause the headlights to be insufficient or too bright, affecting driving safety.

[0003] The Chinese patent with publication number CN108662545B designs a headlight system with a simple circuit structure and convenient installation and control. The brightness of the taillights can be adaptively adjusted according to different braking depths and different following distances, thereby achieving the purpose of reducing damage to the vision of the driver of the following vehicle.

[0004] The Chinese patent with publication number CN101365276A combines an MCU (microcontroller) with an AFS system (adaptive front lighting system) to design a headlight that can move up and down.

[0005] Both of the above patents are implemented based on external conditions or additional systems, and do not improve the internal characteristics of the vehicle body. Summary of the invention

[0006] The technical problem to be solved by the present invention is: in order to solve the problems existing in the prior art in the above-mentioned background technology, a vehicle light control system with adaptive current change and a control method thereof are provided.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a vehicle light control system with adaptive current change, comprising: A voltage detection unit, used to detect the power supply voltage of the vehicle body; A low voltage drop linear voltage regulator unit is used to reduce the power supply voltage and provide a stable voltage for the microcontroller unit; A signal detection unit, used for detecting a vehicle body input signal and transmitting the filtered signal to a microcontroller unit; The headlight driving unit is used to control the LED of the headlight and feed back the fault information to the microcontroller unit; A step-up and step-down conversion unit is used to provide a stable voltage to the headlight driving unit; The microcontroller unit determines whether to implement a current reduction strategy and / or control the vehicle lamp driving unit to execute a lighting action based on the data received from the voltage detection unit and the low voltage difference linear voltage regulator unit and the input signal of the acquisition signal detection unit.

[0008] Furthermore, the voltage detection unit includes an input voltage, a voltage dividing resistor R1, a voltage dividing resistor R2, a circuit protection resistor R3 and a circuit protection capacitor C, one end of the voltage dividing resistor R1 is connected to the input voltage, and the other end thereof is respectively connected to one end of the voltage dividing resistor R2 and the circuit protection resistor R3, the other end of the voltage dividing resistor R2 is grounded, the other end of the circuit protection resistor R3 is a detection point, one end of the circuit protection capacitor C is connected to this end of the circuit protection resistor R3, and the other end thereof is grounded.

[0009] Furthermore, the resistance ratio of the voltage-dividing resistor 1 R1 to the voltage-dividing resistor 2 R2 is 4:1, and the voltage at the detection point is 1 / 5 of the input voltage.

[0010] Furthermore, the vehicle body input signal includes a position light signal, a brake light signal, a fog light signal, a reversing light signal and a LOGO light signal, and the signal detection unit outputs a filtered low-level signal, which is connected to the vehicle light signal pin of the microcontroller unit.

[0011] A control method for a vehicle light control system with adaptive current change in the above solution is also provided, comprising the following steps: S1, the step-up and step-down conversion unit clamps the body power supply voltage at the set value I, providing a stable voltage for the body drive; S2, the low voltage drop linear voltage regulator unit clamps the body power supply voltage to 5V, providing a stable voltage for the microcontroller unit; S3, the voltage detection unit detects the body power supply voltage. If the body power supply voltage is less than the set value II, the microcontroller unit starts to implement the current reduction strategy; S4, the microcontroller unit detects the vehicle light signal input from the vehicle body. If the input vehicle light signal is detected, the microcontroller unit transmits the lighting information to the driving unit; S5. The headlight driving unit lights up the LED corresponding to the headlight signal, completes the execution of lighting, extinguishing and animation, and at the same time, handles the fault feedback task.

[0012] Further, in step S1, when the vehicle body power supply voltage is less than the minimum value of the normal working voltage of the boost-buck conversion unit, the circuit output current formula after the boost-buck conversion unit clamps the voltage is as follows: (1), In formula (1), I i is the total current of the circuit, Vout is the voltage clamped by the step-up / step-down converter unit, I out is the output current of the step-up / step-down converter unit, η is the power parameter; from formula (1), we can see that the total current of the entire circuit will be converted and amplified.

[0013] Further, in step S3, the voltage at the detection point in the voltage detection unit is reduced by a resistor divider and then transmitted to the microcontroller unit. Vcc As a reference voltage, calculate the analog signal to digital signal value. The calculation formula is as follows: (2) In formula (2), ADC is the ADC value corresponding to the input voltage, V is the voltage at the detection point of the voltage detection unit, Vcc is the operating voltage of the microcontroller unit, as a reference voltage, 5000 is Vcc The analog signal is converted into a digital signal reference value.

[0014] Furthermore, the AD sampling period in the microcontroller unit is 1 ms, 10 AD samplings form a group, the 10 sampling values ​​are sorted, the maximum value and the minimum value are removed, the remaining 8 AD values ​​are averaged, and the average value is used as an AD sampling value of the input voltage; If the input voltage for normal operation is 9-20V, the microcontroller unit calculates the voltage value of the input voltage through AD sampling. When the voltage value is 9-20V, it outputs a normal voltage sign; when the voltage value is 7-9V, it outputs a low voltage sign; when the voltage value is 6-7V, it outputs an ultra-low voltage sign; when the voltage value is below 6V, it outputs a sign to turn off all lights; Taking into account the fluctuation of the vehicle body voltage at the critical value and the error in the AD sampling of the microcontroller unit, a receipt interval is set at the critical value of the input voltage. Specifically, the receipt interval of 6V is [5.7, 6], the receipt interval of 7V is [6.7, 7.3], and the receipt interval of 9V is [8.7, 9.3]. When the AD sampling value of the input voltage is within the receipt interval, the output flag bit remains in the previous state.

[0015] Furthermore, the specific steps of implementing the current reduction strategy are: When the microcontroller unit obtains a normal voltage mark, the microcontroller unit pin corresponding to the headlight sends a high level, and the headlight driving unit turns on the headlight; when the microcontroller unit pin corresponding to the headlight sends a low level, the headlight driving unit turns off the headlight; When the microcontroller unit obtains a low voltage flag, the microcontroller unit sends a PWM signal with a duty cycle of 70%, and the MOS tube of the headlight drive unit is closed for 30% of the time, that is, the current flowing through the drive drops by 30%, completing the operation of the headlight current reduction strategy; When the microcontroller unit obtains the ultra-low voltage flag, the microcontroller unit sends a PWM signal with a duty cycle of 50%, and the MOS tube of the headlight drive unit is closed 50% of the time, that is, the current flowing through the drive drops by 50%, completing the operation of the position light current reduction strategy; If the headlight driving unit feeds back fault information to the microcontroller unit, the microcontroller unit sends an instruction to the driver, and the driver executes the instruction corresponding to turning off the headlight.

[0016] Further, in step S4, the signal detection unit filters the vehicle body signal and sends it to the microcontroller unit. The microcontroller unit obtains the signal transmitted by the signal detection unit through AD sampling. The AD sampling period is 1ms. After sampling the light-on signal for 5 consecutive times, the microcontroller unit sends a light-on command to the headlight driving unit.

[0017] Beneficial effects of the present invention: The vehicle lamp current adaptive control system of the present invention can keep the vehicle lamps lit in a low voltage state and prevent the internal components of the lamps from being damaged by high currents. The present invention aims at the high current generated when the vehicle body is in a low-voltage state, and enables the microcontroller to send 50% or 70% PWM to the driving unit. Under the condition of constant driving voltage, the current when driving the lamp is reduced, and the electronic components of the lamp work within the rated power, thereby extending the service life of the lamp. The microcontroller of the present invention acquires the signal transmitted by the signal detection unit through AD sampling, fixes the AD sampling period, improves the sampling frequency and detection degree, overcomes the problems such as pulse interference generated by the vehicle body, and improves the control accuracy of the vehicle lights; The present invention sets a receipt interval at the AD detection point to stabilize the AD detection result and the status flag sent by the microcontroller, thereby solving the problem of the vehicle body voltage fluctuating back and forth at the AD detection point and ensuring that the vehicle lights do not flicker when working in a low-voltage state. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1 It is a control block diagram of the vehicle light control system of the present invention.

[0020] FIG2 is a circuit diagram of the vehicle light control system of the present invention; wherein, Figure 2a It is the circuit schematic diagram of the signal detection unit; Figure 2b It is the schematic diagram of the boost and buck unit circuit; Figure 2cIt is the circuit schematic diagram of the low voltage linear voltage regulator unit; Figure 2d It is the schematic diagram of the drive unit and LED circuit.

[0021] Figure 3 It is a circuit schematic diagram of the voltage detection unit in the present invention.

[0022] Figure 4 It is a flow chart of the control method of the present invention.

[0023] Figure 5 It is a strategy diagram for reducing the current of vehicle lights in the control method of the present invention.

[0024] Figure 6 It is a flow chart of the vehicle light current reduction in the control method of the present invention.

[0025] Figure 7 It is a flow chart of vehicle body signal detection in the control method of the present invention.

[0026] In the figure: 1. Voltage detection unit, 2. Low voltage difference linear voltage regulator unit; 3. Signal detection unit; 4. Headlight driving unit; 5. Boost and buck conversion unit; 6. Microcontroller unit. DETAILED DESCRIPTION

[0027] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0028] like Figure 1 As shown in FIG2 , a current adaptively changing headlight control system includes a voltage detection unit 1, a low voltage drop linear voltage regulator unit (LDO) 2, a signal detection unit 3, a headlight driving unit 4, a step-up / step-down conversion unit 5 and a microcontroller unit (MCU) 6, wherein the voltage detection unit 1 is used to detect the body power supply voltage. In this embodiment, the body power supply voltage is KL30, which provides the working voltage of the ECU (electronic control unit), which is generally 11V to 15V; the low voltage drop linear voltage regulator unit (LDO) 2 is used to reduce the power supply voltage and provide a stable voltage for the microcontroller unit (MCU) 6; The signal detection unit 3 is used to detect the input signal of the vehicle body and transmit the filtered signal to the microcontroller unit (MCU) 6; the headlight driving unit 4 is used to control the lighting of the LED of the headlight and feed back the fault information to the microcontroller unit (MCU) 6; the step-up and step-down conversion unit 5 is used to provide a stable voltage to the headlight driving unit 4; the microcontroller unit (MCU) 6 determines whether to implement a current reduction strategy and / or control the headlight driving unit 4 to execute a lighting action based on the data received from the voltage detection unit 1 and the low-voltage difference linear voltage regulator unit 2, and the input signal of the signal detection unit 3.

[0029] like Figure 2a As shown in the figure, the body input signal Tail is filtered by capacitors (TC54, TC61), giving a high level to the gate of transistor Q1, and the level of T-Signal is pulled low. When the MCU detects the low level at T-Signal, it can send a lighting instruction to the body driver.

[0030] Figure 2b The input Vbat of the boost and buck voltage is KL30, and the output V_OUT is used as the input voltage of the vehicle body drive. The input of the boost and buck conversion unit 5 is KL30, and the output is a fixed voltage (6-20V), which provides a stable voltage to the headlight drive unit 4 to prevent the interference of headlight pulses and noise, causing the headlights to flicker.

[0031] Figure 2c The input Vcc of the LDO is KL30, and the output is a stable 5V voltage. The 5V voltage provides a stable voltage to the MCU to prevent interference from the light pulse and noise, so that the MCU can work normally. The input of the MCU is 5V voltage, the lighting signal detected by the body, the AD value of the voltage detection and the fault signal fed back by the drive unit. The output is the command to control the lighting of the drive unit 4 (the lighting command includes turning on the light, turning off the light and animation lighting) and the current reduction strategy.

[0032] Figure 2d The input of the headlight driver unit 4 is the fixed voltage (VCC_S) generated by the step-up / step-down converter unit 5 and the lighting command (EN and VCC_P) issued by the MCU. The output is the lighting action SLED1 (the lighting action includes turning on the light, turning off the light, and turning on the light with animation, etc.) and the feedback fault FAULT (open circuit and short circuit of LED). The vehicle body input signal includes the position light signal, brake light signal, fog light signal, reversing light signal and LOGO light signal. The signal detection unit 3 outputs the filtered low-level signal and connects to the headlight signal pin of the MCU. The headlight signal pin of the MCU receives the low-level signal issued by the signal detection unit 3, and the MCU sends a headlight lighting signal to the headlight driver unit 4.

[0033] like Figure 3 As shown, the voltage detection unit 1 includes an input voltage (KL30), a voltage divider resistor R1, a voltage divider resistor R2, a circuit protection resistor R3 and a circuit protection capacitor C. One end of the voltage divider resistor R1 is connected to the input voltage, and the other end thereof is respectively connected to one end of the voltage divider resistor R2 and the circuit protection resistor R3. The other end of the voltage divider resistor R2 is grounded, and the other end of the circuit protection resistor R3 is a detection point. One end of the circuit protection capacitor C is connected to the end of the circuit protection resistor R3, and the other end thereof is grounded. Among them, the resistance ratio of the voltage divider resistor R1 and the voltage divider resistor R2 is 4:1. According to the voltage division principle, the voltage at the detection point is 1 / 5 of KL30. The detection point can be directly connected to the AD module of the MCU for voltage detection.

[0034] like Figure 4 As shown, a control method of a vehicle light control system with adaptive current change includes the following steps: S1, the step-up / step-down conversion unit 5 clamps the vehicle body power supply voltage at the set value I, providing a stable voltage for vehicle body driving; S2, the low voltage drop linear voltage regulator unit 2 clamps the body power supply voltage to 5V, providing a stable voltage for the microcontroller unit 6; S3, the voltage detection unit 1 detects the body power supply voltage. If the body power supply voltage is less than the set value II, the microcontroller unit 6 starts to implement the current reduction strategy; S4, the microcontroller unit 6 detects the vehicle light signal input from the vehicle body. If the input vehicle light signal is detected, the microcontroller unit 6 transmits the lighting information to the driving unit; S5, the headlight driving unit 4 lights up the LED corresponding to the headlight signal, completes the execution of lighting, extinguishing and animation, and at the same time, processes the fault feedback task.

[0035] Among them, in step S1, the input voltage of the boost-buck conversion unit is KL30 (6-20V), and the output voltage is fixed at 12V after the boost-buck circuit. When the KL30 input voltage is 9V-20V, the boost-buck conversion unit works normally. When the vehicle body power supply voltage (if the KL30 input voltage is 6V-9V) is less than the minimum value of the normal working voltage of the boost-buck conversion unit, the circuit output current formula after the boost-buck conversion unit clamps the voltage is as follows: (1), In formula (1), I i is the total current of the circuit, V out is the voltage clamped by the step-up / step-down converter unit, I out is the output current of the step-up / step-down converter unit, η is the power parameter; from formula (1), we can see that the total current of the entire circuit will be converted and amplified, and at this time it is necessary to implement a current reduction strategy for the circuit.

[0036] The input of LDO is KL30 (6~20V), and after the current reduction circuit, it outputs 5V voltage. LDO provides stable voltage for MCU to ensure stable operation of MCU.

[0037] In step S3, MCU can obtain the voltage of KL30 through AD detection. Since the operating voltage of MCU is 5V, the voltage detected by AD must be less than 5V. Through resistor voltage division, the detection point voltage of voltage detection unit 1 is 1 / 5 of KL30. The detection point voltage is lower than the normal working voltage of MCU. MCU can obtain the voltage of KL30 through AD detection. MUC and itself Vcc As a reference voltage, calculate the analog signal to digital signal value. The calculation formula is as follows: (2) In formula (2), ADC is the ADC value corresponding to the input voltage, V is the voltage at the detection point of the voltage detection unit, Vcc is the operating voltage of the microcontroller unit, as a reference voltage, 5000 is Vcc The analog signal is converted into a digital signal reference value.

[0038] The AD sampling cycle in the MCU is 1ms, and AD sampling is 10 times as a group. The 10 sampling values ​​are sorted, the maximum and minimum values ​​are removed, and the remaining 8 AD values ​​are averaged, and this average value is used as an AD sampling value of the input voltage; if the normal working input voltage is 9-20V, the microcontroller unit calculates the voltage value of the input voltage through AD sampling. When the voltage value is 9-20V, the normal voltage mark is output; when the voltage value is 7-9V, the low voltage mark is output; when the voltage value is 6-7V, the ultra-low voltage mark is output; when the voltage value is below 6V, the sign of turning off all lights is output; considering that the body voltage fluctuates at the critical value and there is an error in the AD sampling of the microcontroller unit, a receipt interval is set at the critical value of the input voltage, specifically: the receipt interval of 6V is [5.7, 6], the receipt interval of 7V is [6.7, 7.3], and the receipt interval of 9V is [8.7, 9.3]. When the AD sampling value of the input voltage is within the receipt interval, the output flag bit remains in the previous state.

[0039] Current reduction strategies such as Figure 5As shown in the figure, the detection cycle of the MCU is 1ms, and the results of 10 AD detections are 1 group, and the data of this group is stored in the array BUF

[10] . Then, the 10 elements in BUF

[10] are sorted from small to large, and the values ​​of BUF[1] to BUF[8] are taken out, and the average of these 8 values ​​is calculated, which is recorded as Ave. Because the MCU has been working after the car lights are powered on, Ave can be obtained in real time. At this time, the average value Ave represents the AD value of KL30. When the average value Ave is less than or equal to 5.7V, the MCU sends a light-off mark to the driver. When the average value Ave is greater than 6V and less than or equal to 6.7V, the MCU sends an ultra-low voltage mark. When the average value Ave is greater than 7.3V and less than or equal to 8.7V, the MCU sends a low voltage mark. When the average value Ave is greater than 9.3V, the MCU sends a normal voltage mark. When the average value Ave is greater than 5.7V and less than or equal to 6V, the MCU sends the mark of the previous moment to prevent KL30 from fluctuating around 6V. The MCU continues to send the light-off mark and the ultra-low voltage mark to avoid causing the lights to flicker. When the average value Ave is greater than 6.7V and less than or equal to 7.3V, the MCU sends the mark of the previous moment to prevent KL30 from fluctuating around 7V. The MCU continues to send the ultra-low voltage mark and the low voltage mark to avoid causing the lights to flicker. When the average value Ave is greater than 8.7V and less than or equal to 9.3V, the MCU sends the mark of the previous moment to prevent KL30 from fluctuating around 9V. The MCU continues to send the low voltage mark and the normal voltage mark to avoid causing the lights to flicker.

[0040] The specific steps of implementing the current reduction strategy are as follows: when the MCU obtains a normal voltage mark, the microcontroller pin corresponding to the headlight (turn signal, fog light, reversing light, LOGO light, etc.) sends a high level, and the headlight drive unit 4 turns on the light, and the MCU pin corresponding to the headlight sends a low level, and the headlight drive unit 4 turns off the light; when the MCU obtains a low voltage mark, the MCU sends a PWM signal with a duty cycle of 70%, and the MOS tube of the headlight drive unit 4 is turned off 30% of the time, that is, the current flowing through the drive decreases by 30%, completing the operation of the headlight current reduction strategy; when the micro MCU obtains an ultra-low voltage mark, the MCU sends a PWM signal with a duty cycle of 50%, and the MOS tube of the headlight drive unit 4 is turned off 50% of the time, that is, the current flowing through the drive decreases by 50%, completing the operation of the position light current reduction strategy; if the headlight drive unit 4 feeds back fault information to the MCU, the MCU sends an instruction to the driver, and the driver executes the instruction to turn off the corresponding headlight.

[0041] The step-up / step-down conversion unit 5 provides a stable voltage for the vehicle body drive, and the instruction issued by the MCU provides a lighting signal for the drive. Figure 6As shown, when the MCU obtains the light-off sign, an enable signal with a duty cycle of 0% is sent to the headlight drive unit 4. When the MCU obtains the ultra-low voltage sign, an enable signal with a duty cycle of 50% is sent to the headlight drive unit 4. When the MCU obtains the low voltage sign, an enable signal with a duty cycle of 70% is sent to the headlight drive unit 4. When the MCU obtains the normal voltage sign, an enable signal with a duty cycle of 100% is sent to the headlight drive unit 4. In addition, when the MCU detects a fault signal fed back by the drive unit, the MCU will send an enable signal with a duty cycle of 0% to the drive unit, meeting the requirement that if one LED is damaged, the entire headlight will be turned off.

[0042] In step S4, the signal detection unit 3 filters the vehicle body signal and sends it to the MCU. The MCU obtains the signal transmitted by the signal detection unit through AD sampling. The AD sampling period is 1ms. After sampling the light-on signal for 5 consecutive times, the MCU sends a light-on command to the headlight driving unit.

[0043] The vehicle body electronic control unit sends a lighting signal for the position lights (turn lights, fog lights, reversing lights, and LOGO lights, etc.). The signal detection unit 3 filters the lighting signal and converts it into a high or low level that the MCU can understand. Figure 7 As shown in the figure, the cycle of MCU detecting high and low levels is 1ms. If the low level is detected for 5 consecutive times, the MCU sends a light-on instruction to the lamp driving unit 4. If the high level is detected for 5 consecutive times, the MCU sends a light-off instruction to the lamp driving unit 4. If the same level is not detected for 5 consecutive times, the MCU will send the last instruction; the reason for detecting the same level for 5 consecutive times is to filter the pulses and noise generated inside the car body to prevent the MCU from treating the pulses and noise as detection signals, which will cause the MCU to issue wrong instructions.

[0044] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A vehicle light control system with adaptive current change, characterized in that: include: A voltage detection unit, used to detect the power supply voltage of the vehicle body; A low voltage drop linear voltage regulator unit is used to reduce the power supply voltage and provide a stable voltage for the microcontroller unit; A signal detection unit, used for detecting a vehicle body input signal and transmitting the filtered signal to a microcontroller unit; The headlight driving unit is used to control the LED of the headlight and feed back the fault information to the microcontroller unit; A step-up and step-down conversion unit is used to provide a stable voltage to the headlight driving unit; The microcontroller unit determines whether to implement a current reduction strategy and / or control the vehicle lamp driving unit to execute a lighting action based on the data received from the voltage detection unit and the low voltage difference linear voltage regulator unit and the input signal of the acquisition signal detection unit.

2. The vehicle light control system with adaptive current change according to claim 1, characterized in that: The voltage detection unit includes an input voltage, a voltage dividing resistor R1, a voltage dividing resistor R2, a circuit protection resistor R3 and a circuit protection capacitor C. One end of the voltage dividing resistor R1 is connected to the input voltage, and the other end thereof is respectively connected to one end of the voltage dividing resistor R2 and the circuit protection resistor R3. The other end of the voltage dividing resistor R2 is grounded, and the other end of the circuit protection resistor R3 is a detection point. One end of the circuit protection capacitor C is connected to this end of the circuit protection resistor R3, and the other end thereof is grounded.

3. The vehicle light control system with adaptive current change according to claim 2, characterized in that: The resistance ratio of the voltage-dividing resistor 1 R1 to the voltage-dividing resistor 2 R2 is 4:1, and the voltage at the detection point is 1 / 5 of the input voltage.

4. The vehicle light control system with adaptive current change according to claim 1, characterized in that: The vehicle body input signals include position light signals, brake light signals, fog light signals, reversing light signals and LOGO light signals. The signal detection unit outputs a filtered low-level signal, which is connected to the vehicle light signal pin of the microcontroller unit.

5. A control method for a vehicle light control system with adaptive current change according to any one of claims 1 to 4, characterized in that: The steps include: S1, the step-up and step-down conversion unit clamps the body power supply voltage at the set value I, providing a stable voltage for the body drive; S2, the low voltage drop linear voltage regulator unit clamps the body power supply voltage to 5V, providing a stable voltage for the microcontroller unit; S3, the voltage detection unit detects the body power supply voltage. If the body power supply voltage is less than the set value II, the microcontroller unit starts to implement the current reduction strategy; S4, the microcontroller unit detects the vehicle light signal input from the vehicle body. If the input vehicle light signal is detected, the microcontroller unit transmits the lighting information to the driving unit; S5. The headlight driving unit lights up the LED corresponding to the headlight signal, completes the execution of lighting, extinguishing and animation, and at the same time, handles the fault feedback task.

6. The control method of the vehicle light control system with adaptive current change according to claim 5, characterized in that: In step S1, when the vehicle body power supply voltage is less than the minimum value of the normal working voltage of the boost-buck conversion unit, the circuit output current formula after the boost-buck conversion unit clamps the voltage is as follows: （1）， In formula (1), I i is the total current of the circuit, V out is the voltage clamped by the step-up / step-down converter unit, I out is the output current of the step-up / step-down converter unit, η is the power parameter; from formula (1), we can see that the total current of the entire circuit will be converted and amplified.

7. The control method of the vehicle light control system with adaptive current change according to claim 5, characterized in that: In step S3, the voltage at the detection point in the voltage detection unit is reduced by a resistor divider and then transmitted to the microcontroller unit. Vcc As a reference voltage, calculate the analog signal to digital signal value. The calculation formula is as follows: （2） In formula (2), ADC is the ADC value corresponding to the input voltage, V is the voltage at the detection point of the voltage detection unit, Vcc is the operating voltage of the microcontroller unit, as a reference voltage, 5000 is Vcc The analog signal is converted into a digital signal reference value.

8. The control method of the vehicle light control system with adaptive current change according to claim 7, characterized in that: The AD sampling cycle in the microcontroller unit is 1ms, 10 AD samplings form a group, the 10 sampling values ​​are sorted, the maximum and minimum values ​​are removed, the remaining 8 AD values ​​are averaged, and the average value is used as an AD sampling value of the input voltage; If the input voltage for normal operation is 9-20V, the microcontroller unit calculates the voltage value of the input voltage through AD sampling. When the voltage value is 9-20V, it outputs a normal voltage sign; when the voltage value is 7-9V, it outputs a low voltage sign; when the voltage value is 6-7V, it outputs an ultra-low voltage sign; when the voltage value is below 6V, it outputs a sign to turn off all lights; Taking into account the fluctuation of the vehicle body voltage at the critical value and the error in the AD sampling of the microcontroller unit, a receipt interval is set at the critical value of the input voltage. Specifically, the receipt interval of 6V is [5.7, 6], the receipt interval of 7V is [6.7, 7.3], and the receipt interval of 9V is [8.7, 9.3]. When the AD sampling value of the input voltage is within the receipt interval, the output flag bit remains in the previous state.

9. The control method of the vehicle light control system with adaptive current change according to claim 8, characterized in that: The specific steps to implement the current reduction strategy are: When the microcontroller unit obtains a normal voltage mark, the microcontroller unit pin corresponding to the headlight sends a high level, and the headlight driving unit turns on the headlight; when the microcontroller unit pin corresponding to the headlight sends a low level, the headlight driving unit turns off the headlight; When the microcontroller unit obtains a low voltage flag, the microcontroller unit sends a PWM signal with a duty cycle of 70%, and the MOS tube of the headlight drive unit is closed for 30% of the time, that is, the current flowing through the drive drops by 30%, completing the operation of the headlight current reduction strategy; When the microcontroller unit obtains the ultra-low voltage flag, the microcontroller unit sends a PWM signal with a duty cycle of 50%, and the MOS tube of the headlight drive unit is closed 50% of the time, that is, the current flowing through the drive drops by 50%, completing the operation of the position light current reduction strategy; If the headlight driving unit feeds back fault information to the microcontroller unit, the microcontroller unit sends an instruction to the driver, and the driver executes the instruction corresponding to turning off the headlight.

10. The control method of the vehicle light control system with adaptive current change according to claim 5, characterized in that: In step S4, the signal detection unit filters the vehicle body signal and sends it to the microcontroller unit. The microcontroller unit obtains the signal transmitted by the signal detection unit through AD sampling. The AD sampling period is 1ms. After sampling the light-on signal for 5 consecutive times, the microcontroller unit sends a light-on command to the headlight driving unit.

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