Vehicle lamp power supply circuit with overvoltage protection

Abstract

The utility model provides a vehicle lamp power supply circuit with overvoltage protection, which comprises a power supply for providing electric energy, the power supply is connected with a load circuit through a driving circuit, the power supply is electrically connected with the driving circuit through a protection circuit, and overvoltage protection is carried out on the driving circuit and the load circuit; the driving circuit comprises a driving chip U1 with an EN pin connected with a power supply, the overvoltage protection circuit comprises a triode T1, a diode D2 is connected in series between a base electrode of the triode T1 and the power supply, an emitting electrode of the triode T1 is connected with a ground electrode, a collector electrode of the triode T1 is connected with the EN pin of the driving chip U1, and the driving chip U1 is connected with the power supply. An IN pin, an EN pin and a PWM pin of the driving chip U1 are connected with the output end of the power supply, and an OUT pin of the driving chip U1 is electrically connected with the input end of the load circuit. The over-voltage protection circuit can efficiently and quickly carry out over-voltage protection, and the service life of the automobile lamp is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle lamp power supply, in particular to a vehicle lamp power supply circuit with overvoltage protection. Background Art

[0002] The new generation of light source LED has been applied to car lights. According to the different needs of each headlight, choose the appropriate LED product. LED can be combined into LED arrays in different ways such as series connection and parallel connection to meet the requirements of car lighting intensity. According to the light-emitting characteristics of LED, the driving voltage requirements of LED headlights must be met.

[0003] In actual applications, the driving circuit of LED lights does not have power overvoltage protection. When the input power voltage exceeds the rated voltage, the driving circuit will not be disconnected, resulting in increased driving power and heat. The driver chip will break down due to thermal breakdown, causing the LED to not light up normally. There are chips that can provide overvoltage protection in the prior art, but these chips are expensive, which greatly increases the cost. Utility Model Content

[0004] In view of this, the problem to be solved by the utility model is to provide a vehicle lamp power supply circuit with overvoltage protection, which can use a simple circuit to perform overvoltage protection on the vehicle lamp, thereby increasing the service life of the vehicle lamp and saving production costs.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0006] A vehicle light power supply circuit with overvoltage protection includes a power supply for providing electric energy, the power supply is connected to a load circuit via a drive circuit, the power supply is electrically connected to the drive circuit via a protection circuit, and overvoltage protection is performed on the drive circuit and the load circuit;

[0007] The driving circuit includes a driving chip U1 whose EN pin is connected to a power supply, and the overvoltage protection circuit includes a transistor T1, a diode D2 is connected in series between the base of the transistor T1 and the power supply, the emitter of the transistor T1 is connected to the ground, and the collector of the transistor T1 is connected to the EN pin of the driving chip U1.

[0008] Furthermore, the IN pin, EN pin and PWM pin of the driving chip U1 are all connected to the output end of the power supply, and the OUT pin of the driving chip U1 is electrically connected to the input end of the load circuit.

[0009] Furthermore, a diode D1 is connected in series between the power supply and the driving circuit.

[0010] Furthermore, a Zener diode TVS, a resistor R1 and a capacitor C3 are connected in series between the output end of the power supply and the ground respectively.

[0011] Furthermore, the load circuit includes a light emitting diode LED1, the light emitting diode LED1 is connected in parallel to a capacitor C4, and the light emitting diode LED1 is connected in series to a light emitting diode LED2.

[0012] The advantages and positive effects of the utility model are:

[0013] By setting a protection circuit between the power supply and the control circuit, when the power supply discharge voltage is too high, the diode D2 is broken down, the transistor T1 grounds the EN pin of the driver chip U1, and the driver circuit and the load circuit stop running at the same time to perform overvoltage protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 This is an overall system diagram of a vehicle light power supply circuit with overvoltage protection of the utility model;

[0016] Figure 2 This is a protection circuit diagram in a vehicle light power supply circuit with overvoltage protection of the utility model;

[0017] Figure 3 It is a circuit diagram of a Zener diode TVS, a resistor R1 and a capacitor C3 in a vehicle light power supply circuit with overvoltage protection of the utility model;

[0018] Figure 4 This is a control circuit diagram of a vehicle light power supply circuit with overvoltage protection of the utility model;

[0019] Figure 5 The utility model discloses a load circuit diagram in a vehicle light power supply circuit with overvoltage protection. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0022] The utility model provides a vehicle lamp power supply circuit with overvoltage protection, such as Figure 1 As shown, it includes a power supply for providing electric energy, the output end of the power supply is electrically connected to the control module, and the output end of the control module is connected to the input end of the load circuit. The control module supplies power to the load circuit according to the power supply condition of the power supply.

[0023] like Figure 3 and Figure 4 As shown, the control module includes a control chip U1, and a resistor R5 is connected in series between the IN pin of the control chip U1 and the power supply to provide a voltage of a set pressure to the control chip U1. A resistor R6 is connected in series between the PWM pin of the control chip U1 and the power supply, and the resistor R6 is used to adjust the input voltage of the PWM pin. When the power supply is discharged, the voltage of the PWM pin is pulled up, and the OUT pin of the control chip U1 outputs electrical energy to power the load circuit.

[0024] A resistor R3 is connected in series between the EN pin of the control chip U1 and the power supply, the EN pin voltage is pulled high, and the control chip U1 operates normally. A protection circuit is connected in series between the EN pin of the control chip U1 and the power supply, and the protection circuit is used to monitor the output voltage of the power supply. When the output voltage of the power supply is too high, the protection circuit pulls down the voltage of the EN pin, and the control chip U1 stops operating.

[0025] like Figure 2 As shown, the protection circuit includes a transistor T1, the collector of the transistor T1 is connected to the EN pin of the control chip U1, the emitter of the transistor T1 is connected to the ground, and a diode D2 is connected in series between the base of the transistor T1 and the power supply. When the voltage of the power supply is higher than the threshold, the diode D2 and the transistor T1 are turned on in sequence, the EN pin of the control chip U1 is grounded, and the control chip U1 stops running, thereby protecting the drive circuit and the load circuit under high voltage and improving the service life of the drive circuit and the load circuit.

[0026] In order to improve the stability of the power supply output voltage, a Zener diode TVS, a resistor R1 and a capacitor C3 are connected in series between the output end of the power supply and the ground respectively. The Zener diode TVS is used to absorb the peak current, and the capacitor C3 is used to stabilize the current.

[0027] A diode D1 is connected in series between the power supply and the control circuit to prevent current backflow and affect the power supply performance.

[0028] A light emitting diode LED1 is connected in series between the input end and the ground of the load circuit, the light emitting diode LED1 is connected in parallel to a capacitor C4, the light emitting diode LED1 is connected in series to a light emitting diode LED2, and the capacitor C4 is used to improve the stability of the output voltage of the OUT pin of the control chip U1.

[0029] The working principle and working process of the utility model are as follows:

[0030] The power supply is discharged, the EN pin, IN pin and PWM pin of the control chip U1 are pulled high at the same time, the OUT pin of the control chip U1 outputs electric energy of the set pressure to power the load circuit, and the light-emitting diodes LED1 and LED2 light up.

[0031] When the power supply discharge voltage is too high, the diode D2 is broken down, the transistor T1 is turned on, and the EN pin of the control chip U1 is grounded. The control chip U1 stops running, and the light-emitting diodes LED1 and LED2 are turned off, thereby protecting the drive circuit and the load circuit under high voltage.

[0032] The above embodiments of the utility model are described in detail, but the above contents are only preferred embodiments of the utility model and cannot be considered to limit the scope of implementation of the utility model. All equivalent changes and improvements made within the scope of the utility model should still fall within the scope of this patent.

Claims

1. A vehicle light power supply circuit with overvoltage protection, characterized in that: It includes a power supply for providing electric energy, the power supply is connected to the load circuit through the drive circuit, the power supply is electrically connected to the drive circuit through the protection circuit, and the drive circuit and the load circuit are protected from overvoltage; The driving circuit includes a driving chip U1 whose EN pin is connected to a power supply, and the overvoltage protection circuit includes a transistor T1, a diode D2 is connected in series between the base of the transistor T1 and the power supply, the emitter of the transistor T1 is connected to the ground, and the collector of the transistor T1 is connected to the EN pin of the driving chip U1.

2. A vehicle light power supply circuit with overvoltage protection according to claim 1, characterized in that: The IN pin, EN pin and PWM pin of the driving chip U1 are all connected to the output end of the power supply, and the OUT pin of the driving chip U1 is electrically connected to the input end of the load circuit.

3. The vehicle light power supply circuit with overvoltage protection according to claim 1, characterized in that: A diode D1 is connected in series between the power supply and the driving circuit.

4. The vehicle light power supply circuit with overvoltage protection according to claim 1, characterized in that: A Zener diode TVS, a resistor R1 and a capacitor C3 are connected in series between the output end of the power supply and the ground respectively.

5. The vehicle light power supply circuit with overvoltage protection according to claim 1, characterized in that: The load circuit includes a light emitting diode LED1, the light emitting diode LED1 is connected in parallel to a capacitor C4, and the light emitting diode LED1 is connected in series to a light emitting diode LED2.

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