Car lamp control system

Abstract

The utility model relates to the technical field of car lamp control, in particular to a car lamp control system. Comprising a filter circuit, and the input end of the filter circuit is controllably connected with vehicle input voltage; the anode of the anti-reverse diode is connected with the output end of the filter circuit; the input end of the linear voltage regulator is connected with the cathode of the anti-reverse diode; the output end of the microprocessor is connected with the output end of the linear voltage stabilizer; and the vehicle lamp controller receives the vehicle lamp control signal output by the microprocessor, and the output end of the vehicle lamp controller is connected with a vehicle lamp to output a vehicle lamp driving signal. The diode is additionally arranged at the input end of the linear voltage regulator to serve as a protection diode, due to the reverse cut-off characteristic of the diode, even if the output voltage is larger than the input voltage, reverse current has no loop to the ground at the moment, and the chip can be effectively prevented from losing efficacy.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle light control, in particular to a vehicle light control system. Background Art

[0002] Low-dropout (LDO) linear regulators (LDOs) are widely used in the automotive lighting industry. For example, in lighting controllers, they typically convert the vehicle's 12V system power supply to 5V to provide the microprocessor's power supply voltage. Typically, if the main power supply has anti-reverse-current components, the diode design is eliminated from the LDO's front end. However, when the vehicle's power supply encounters unusual operating conditions or the controller needs to meet electrical performance requirements, such as rapid power loss due to a vehicle battery failure, the LDO's output has a filter capacitor that discharges during shutdown. If the input voltage drops below the output voltage, reverse current can occur, damaging the chip. Utility Model Content

[0003] The purpose of this utility model is to provide a vehicle light control system to solve the above technical problems;

[0004] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0005] A vehicle light control system, comprising:

[0006] a filter circuit, wherein an input end of the filter circuit is controllably connected to a vehicle body input voltage;

[0007] an anti-reverse diode, wherein the anode of the anti-reverse diode is connected to the output end of the filter circuit;

[0008] A linear voltage regulator, wherein the input end of the linear voltage regulator is connected to the cathode of the anti-reverse diode;

[0009] a microprocessor, wherein an output end of the microprocessor is connected to an output end of the linear regulator;

[0010] A headlight controller receives a headlight control signal output by the microprocessor, and an output end of the headlight controller is connected to the headlight to output a headlight driving signal.

[0011] Preferably, the linear regulator includes:

[0012] an undervoltage lockout protection unit, wherein an input end of the undervoltage lockout protection unit is connected to the cathode of the anti-reverse diode to receive the vehicle body input voltage, a controlled end of the undervoltage lockout protection unit is connected to an enable signal, and an output end of the undervoltage lockout protection unit generates a logic signal based on the vehicle body input voltage;

[0013] a reference voltage unit connected to the output terminal of the undervoltage lockout protection unit and generating a reference voltage based on the logic signal;

[0014] a comparator, wherein a first input terminal of the comparator is connected to the reference voltage unit and receives the reference voltage, a second input terminal of the comparator receives a feedback voltage, and the comparator outputs a comparison signal according to a comparison value between the feedback voltage and the reference voltage;

[0015] A switching tube, wherein the gate of the switching tube is connected to the output end of the comparator, the switching tube is controllably turned on and off according to the comparison signal, the source of the switching tube is connected to the cathode of the anti-reverse diode to receive the vehicle body input voltage, and the drain of the switching tube is the output end of the linear regulator.

[0016] Preferably, it also includes,

[0017] a first resistor, wherein a first end of the first resistor is connected to the drain of the switch tube, a second end of the first resistor generates the feedback voltage, and a second input end of the comparator is connected to the second end of the first resistor to receive the feedback voltage;

[0018] A second resistor, wherein a first end of the second resistor is connected to the second end of the first resistor, and a second end of the second resistor is grounded.

[0019] Preferably, the first resistor is an adjustable resistor.

[0020] Preferably, the power supply voltage terminal of the reference voltage unit and the power supply voltage terminal of the comparator are connected to the cathode of the anti-reverse diode.

[0021] Preferably, the device further includes a first capacitor, wherein a first end of the first capacitor is connected to the anode of the anti-reverse diode, and a second end of the first capacitor is grounded.

[0022] Preferably, a second capacitor is further included, wherein a first end of the second capacitor is connected to the drain of the switch tube, and a second end of the second capacitor is grounded.

[0023] Preferably, the first capacitor and the second capacitor are both ceramic capacitors.

[0024] Preferably, the filter circuit is connected to the vehicle body input voltage via an anti-reverse MOS tube, the source of the anti-reverse MOS tube is connected to the vehicle body input voltage, and the drain of the anti-reverse MOS tube is connected to the filter circuit.

[0025] Preferably, it also includes,

[0026] a transistor, wherein the base of the transistor is connected to a vehicle body control signal via a third resistor;

[0027] a fourth resistor, wherein a first end of the fourth resistor is connected to the collector of the transistor, and a second end of the fourth resistor is connected to the gate of the anti-reverse MOS tube;

[0028] A fifth resistor, wherein a first end of the fifth resistor is connected to the base of the transistor, and a second end of the fifth resistor is connected to the emitter of the transistor and is grounded.

[0029] The beneficial effects of the present invention are as follows: due to the adoption of the above technical solution, the present invention adds an additional diode as a protection diode at the input end of the linear regulator. Due to the reverse cutoff characteristics of the diode, even if the output voltage is greater than the input voltage, the reverse current has no loop to the ground, which can effectively prevent the chip from failing. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a structural diagram of a vehicle light control system in an embodiment of the present utility model;

[0031] Figure 2 Schematic diagram of the structure of a linear regulator in an embodiment of the present utility model.

[0032] In the accompanying drawings: 1. Filter circuit; 2. Linear regulator; 21. Undervoltage lockout protection unit; 22. Reference voltage unit; 23. Comparator; 3. Microprocessor; 4. Headlight controller; 5. Headlight; D1, Anti-reverse diode; R1, First resistor; R2, Second resistor; R3, Third resistor; R4, Fourth resistor; R5, Fifth resistor; C1, First capacitor; C2, Second capacitor; Q1, Switch tube; Q2, Anti-reverse MOS tube; Q3, Transistor. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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.

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0036] A vehicle light control system, such as Figure 1 Shown, including,

[0037] A filter circuit 1, wherein an input terminal of the filter circuit 1 is controllably connected to an input voltage of a vehicle body;

[0038] The anti-reverse diode D1 has its anode connected to the output end of the filter circuit 1;

[0039] Linear regulator 2, the input end of the linear regulator 2 is connected to the cathode of the anti-reverse diode D1;

[0040] A microprocessor 3, wherein an output end of the microprocessor 3 is connected to an output end of the linear regulator 2;

[0041] The light controller 4 receives the light control signal output by the microprocessor 3 , and the output end of the light controller 4 is connected to the light 5 to output the light driving signal.

[0042] Specifically, the present invention includes a vehicle body input power supply, a filter circuit 1, an anti-reverse diode D1, a low-voltage dropout linear regulator 2, a microprocessor 3, and a headlight controller 4. The low-voltage dropout linear regulator 2 is primarily used to power the microprocessor 3, and this invention uses a 5V voltage as an example.

[0043] In this utility model, a filter circuit 1 receives the vehicle body input voltage. A reverse current blocking diode D1 protects the circuit from reverse current damage to components. A linear regulator 2 converts the vehicle body input voltage into a stable output voltage. A microprocessor 3 generates a light control signal based on the input signal. A light controller 4 then drives the lights 5 based on the light control signal.

[0044] This utility model incorporates an additional reverse-current protection diode D1 at the front end of the linear regulator 2. When the vehicle power supply experiences a voltage surge under abnormal operating conditions, dropping from a stable output to 0V or even a negative voltage, and the voltage drop rate at the output of the linear regulator 2 is slower than the voltage drop rate at the input of the linear regulator 2, the output voltage may exceed the input voltage, generating a reverse current sink. Adding a diode at the input of the linear regulator 2 as the reverse-current protection diode D1 effectively prevents device failure by preventing the reverse current from flowing to ground even if the output voltage exceeds the input voltage due to the diode's reverse-current blocking characteristics. The selection of the reverse-current protection diode D1 depends on the current level.

[0045] In a preferred embodiment, Figure 2 As shown, the linear regulator 2 includes,

[0046] An undervoltage lockout protection unit 21, wherein the input end of the undervoltage lockout protection unit 21 is connected to the cathode of the anti-reverse diode D1 to receive the vehicle body input voltage, the controlled end of the undervoltage lockout protection unit 21 is connected to an enable signal, and the output end of the undervoltage lockout protection unit 21 generates a logic signal based on the vehicle body input voltage;

[0047] The reference voltage unit 22 is connected to the output terminal of the undervoltage lockout protection unit 21 and generates a reference voltage based on the logic signal;

[0048] A comparator 23, wherein a first input terminal of the comparator 23 is connected to the reference voltage unit 22 and receives a reference voltage, and a second input terminal of the comparator 23 receives a feedback voltage. The comparator 23 outputs a comparison signal according to a comparison value between the feedback voltage and the reference voltage;

[0049] The switching tube Q1 has a gate connected to the output end of the comparator 23. The switching tube Q1 can be controlled to be turned on and off according to the comparison signal. The source of the switching tube Q1 is connected to the cathode of the anti-reverse diode D1 to receive the vehicle body input voltage. The drain of the switching tube Q1 is the output end of the linear regulator 2.

[0050] Specifically, the linear regulator 2 in the present invention includes an undervoltage lockout unit 21, a reference voltage unit 22, a comparator 23, and a switch Q1. The undervoltage lockout unit 21 detects the vehicle body input voltage based on an enable signal to ensure it is within a safe range. The undervoltage lockout unit 21 and the reference voltage unit 22 output a logic signal based on the detection result of the vehicle body input voltage. When the logic signal indicates that the vehicle body input voltage is valid, the reference voltage unit 22 outputs a stable reference voltage. In the present invention, the reference voltage is 1.5V.

[0051] The comparator 23 compares the reference voltage and the feedback voltage, and adjusts the conduction state of the switch tube Q1, thereby controlling the output stable voltage of the switch tube. The linear regulator 2 can maintain a stable output voltage when the input voltage is unstable, and prevent circuit damage through undervoltage protection.

[0052] Specifically, the present invention includes an additional anti-reverse diode D1 at the front end of the linear regulator 2. When the vehicle body power supply experiences a voltage surge under abnormal operating conditions, dropping from a stable output to 0V or even a negative voltage, the first capacitor C1 and the second capacitor C2 discharge simultaneously. When the output voltage of the linear regulator 2 decreases at a slower rate than the input voltage of the linear regulator 2, the output voltage may exceed the input voltage, generating a reverse current. If this current exceeds the maximum current withstand of the body diode of the internal switch Q1, the chip will be damaged. At this time, when power is restored, the output voltage of the linear regulator 2 will show no output. If a diode is added to the input of the linear regulator 2 as an anti-reverse diode D1, due to the reverse cutoff characteristics of the diode, even if the output voltage exceeds the input voltage, the reverse current has no path to ground, effectively preventing chip failure. The selection of the anti-reverse diode D1 depends on the current magnitude.

[0053] In a preferred embodiment, it also includes:

[0054] a first resistor R1, wherein a first end of the first resistor R1 is connected to the drain of the switch Q1, a second end of the first resistor R1 generates a feedback voltage, and a second input end of the comparator 23 is connected to the second end of the first resistor R1 to receive the feedback voltage;

[0055] The second resistor R2 has a first end connected to the second end of the first resistor R1 and a second end grounded.

[0056] Specifically, the first resistor R1 is connected to the output end of the switch tube, and the feedback voltage is generated by voltage division between the first resistor R1 and the second resistor.

[0057] In a preferred embodiment, the first resistor R1 is an adjustable resistor.

[0058] Specifically, the first resistor R1 is an adjustable resistor, and the feedback voltage can be adjusted as needed, thereby affecting the working state of the comparator 23, thereby adjusting the accuracy of the output voltage.

[0059] In a preferred embodiment, the power supply voltage terminal of the reference voltage unit 22 and the power supply voltage terminal of the comparator 23 are connected to the cathode of the anti-reverse diode D1.

[0060] Specifically, the power supply voltage terminal of the reference voltage unit 22 is connected to the cathode of the anti-reverse diode D1, receiving the vehicle body input voltage for power supply; the power supply voltage terminal of the comparator 23 is connected to the cathode of the anti-reverse diode D1, receiving the vehicle body input voltage for power supply.

[0061] In a preferred embodiment, a first capacitor C1 is further included, wherein a first end of the first capacitor C1 is connected to the anode of the anti-reverse diode D1, and a second end of the first capacitor C1 is grounded.

[0062] In a preferred embodiment, a second capacitor C2 is further included, a first end of the second capacitor C2 is connected to the drain of the switch tube Q1, and a second end of the second capacitor C2 is grounded.

[0063] In a preferred embodiment, the first capacitor C1 and the second capacitor C2 are both ceramic capacitors.

[0064] Specifically, in order to provide a stable voltage to the microprocessor 3, the second capacitor C2 is placed at the output end of the linear regulator 2, which can improve the transient response of the load and reduce noise interference. The first capacitor C1 is placed at the input end of the linear regulator 2, which also achieves the beneficial effects of improving the transient response of the load and reducing noise interference. In the present utility model, the first capacitor C1 and the second capacitor C2 are both ceramic capacitors.

[0065] In a preferred embodiment, the filter circuit 1 is connected to the vehicle body input voltage through the anti-reverse MOS transistor Q2 , the source of the anti-reverse MOS transistor Q2 is connected to the vehicle body input voltage, and the drain of the anti-reverse MOS transistor Q2 is connected to the filter circuit 1 .

[0066] Specifically, the present invention adopts an anti-reverse MOS tube Q2 to replace the traditional diode, which has lower conduction loss and reduces the energy loss of the vehicle body input voltage.

[0067] In a preferred embodiment, it also includes:

[0068] Transistor Q3, the base of transistor Q3 is connected to the vehicle body control signal through a third resistor R3;

[0069] a fourth resistor R4, wherein a first end of the fourth resistor R4 is connected to the collector of the transistor Q3, and a second end of the fourth resistor R4 is connected to the gate of the anti-reverse MOS transistor Q2;

[0070] A fifth resistor R5 , wherein a first end of the fifth resistor R5 is connected to the base of the transistor Q3 , and a second end of the fifth resistor R5 is connected to the emitter of the transistor Q3 and is grounded.

[0071] Specifically, the transistor Q3, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 form a control circuit, which controls the conduction of the anti-reverse MOS tube Q2 by adjusting the base signal.

[0072] The above description is only a preferred embodiment of the present invention and does not limit the implementation method and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A vehicle light control system, characterized in that: include, A filter circuit (1), wherein an input end of the filter circuit (1) is controllably connected to a vehicle body input voltage; an anti-reverse diode (D1), wherein the anode of the anti-reverse diode (D1) is connected to the output end of the filter circuit (1); A linear voltage regulator (2), wherein an input end of the linear voltage regulator (2) is connected to the cathode of the anti-reverse diode (D1); A microprocessor (3), wherein an output end of the microprocessor (3) is connected to an output end of the linear regulator (2); A headlight controller (4) receives a headlight control signal output by the microprocessor (3), and an output end of the headlight controller (4) is connected to a headlight (5) to output a headlight driving signal.

2. The vehicle light control system according to claim 1, characterized in that: The linear regulator (2) comprises: An undervoltage lockout protection unit (21), wherein an input end of the undervoltage lockout protection unit (21) is connected to the cathode of the anti-reverse diode (D1) to receive the vehicle body input voltage, a controlled end of the undervoltage lockout protection unit (21) is connected to an enable signal, and an output end of the undervoltage lockout protection unit (21) generates a logic signal based on the vehicle body input voltage; A reference voltage unit (22) is connected to the output end of the undervoltage lockout protection unit (21) and generates a reference voltage based on the logic signal; A comparator (23), wherein a first input terminal of the comparator (23) is connected to the reference voltage unit (22) to receive the reference voltage, a second input terminal of the comparator (23) receives a feedback voltage, and the comparator (23) outputs a comparison signal according to a comparison value between the feedback voltage and the reference voltage; A switching tube (Q1), wherein the gate of the switching tube (Q1) is connected to the output end of the comparator (23), the switching tube (Q1) is controllably turned on and off according to the comparison signal, the source of the switching tube (Q1) is connected to the cathode of the anti-reverse diode (D1) to receive the vehicle body input voltage, and the drain of the switching tube (Q1) is the output end of the linear regulator (2).

3. The vehicle light control system according to claim 2, characterized in that: Also includes, a first resistor (R1), wherein a first end of the first resistor (R1) is connected to the drain of the switch tube (Q1), a second end of the first resistor (R1) generates the feedback voltage, and a second input end of the comparator (23) is connected to the second end of the first resistor (R1) to receive the feedback voltage; A second resistor (R2), wherein a first end of the second resistor (R2) is connected to a second end of the first resistor (R1), and a second end of the second resistor (R2) is grounded.

4. The vehicle light control system according to claim 3, characterized in that: The first resistor (R1) is an adjustable resistor.

5. The vehicle light control system according to claim 2, characterized in that: The power supply voltage terminal of the reference voltage unit (22) and the power supply voltage terminal of the comparator (23) are connected to the cathode of the anti-reverse diode (D1).

6. The vehicle light control system according to claim 2, characterized in that: It also includes a first capacitor (C1), a first end of the first capacitor (C1) is connected to the anode of the anti-reverse diode (D1), and a second end of the first capacitor (C1) is grounded.

7. The vehicle light control system according to claim 6, characterized in that: It also includes a second capacitor (C2), a first end of the second capacitor (C2) is connected to the drain of the switch tube (Q1), and a second end of the second capacitor (C2) is grounded.

8. The vehicle light control system according to claim 7, characterized in that: The first capacitor (C1) and the second capacitor (C2) are both ceramic capacitors.

9. The vehicle light control system according to claim 1, characterized in that: The filter circuit (1) is connected to the vehicle body input voltage via an anti-reverse MOS tube (Q2), the source of the anti-reverse MOS tube (Q2) is connected to the vehicle body input voltage, and the drain of the anti-reverse MOS tube (Q2) is connected to the filter circuit (1).

10. The vehicle light control system according to claim 9, characterized in that: Also includes, a transistor (Q3), wherein a base of the transistor (Q3) is connected to a vehicle body control signal via a third resistor (R3); a fourth resistor (R4), wherein a first end of the fourth resistor (R4) is connected to the collector of the triode (Q3), and a second end of the fourth resistor (R4) is connected to the gate of the anti-reverse MOS tube (Q2); A fifth resistor (R5), wherein a first end of the fifth resistor (R5) is connected to the base of the transistor (Q3), and a second end of the fifth resistor (R5) is connected to the emitter of the transistor (Q3) and is grounded.

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