LED protection circuit for vehicle lamp

Abstract

The LED protection circuit comprises a driving chip, the left side of the driving chip is sequentially connected with a first capacitor, a first resistor and a first diode in series, and the right upper side of the driving chip is connected with an LED lamp; the over-temperature protection device is arranged on the right lower side of the driving chip and comprises a negative temperature coefficient sensor, a second resistor, a second diode and a third resistor, the negative temperature coefficient sensor is connected with the second resistor and the second diode in series, and the third resistor and the negative temperature coefficient sensor are connected with the second resistor and the second diode in parallel. One side of the over-temperature protection device is connected with the driving chip, and the other side is connected with the LED lamp. According to the utility model, the over-temperature protection device is arranged, the temperature of the LED is sensed through the negative temperature coefficient sensor, and when the temperature of the LED rises, the resistance value of the second resistor is reduced, so that the current is closed, and the over-temperature protection is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile parts, in particular to an LED protection circuit for a vehicle lamp. Background Art

[0002] For LED lamps, especially high-power LED car lights, if the design is not done well, the temperature of the LED junction is high, which will cause reversible light decay and irreversible permanent light decay, affecting the performance and life of the LED lamp. In order to increase the reliability of LED lamps, the performance and reliability of the driving power supply need to be improved. A large number of practices have shown that the basic reason why LEDs cannot increase the input power is that LEDs release a large amount of heat during operation, causing the junction temperature of the tube core to rise rapidly. The higher the input power, the greater the heating effect. The increase in temperature will cause changes and attenuation in device performance, and even failure. This research and development has designed an over-temperature protection circuit for the LED drive circuit, thereby reducing the light decay phenomenon of the LED and increasing the service life of the LED. Utility Model Content

[0003] The main purpose of the utility model is to provide an LED protection circuit for vehicle lamps by setting an over-temperature protection device and sensing the temperature of the LED through a negative temperature coefficient sensor. When the temperature of the LED rises, the resistance value of the second resistor will decrease accordingly, thereby shutting off the current and achieving overheat protection.

[0004] In order to solve the above technical problems, the utility model discloses an LED protection circuit for a vehicle lamp, comprising: a driving chip, a first capacitor, a first resistor and a first diode are connected in series in sequence on the left side of the driving chip, and an LED lamp is connected on the upper right side of the driving chip; an over-temperature protection device is arranged on the lower right side of the driving chip, the over-temperature protection device comprises a negative temperature coefficient sensor, a second resistor, a second diode and a third resistor, the negative temperature coefficient sensor is connected in series with the second resistor and the second diode, the third resistor and the negative temperature coefficient sensor are connected in parallel with the second resistor and the second diode, one side of the over-temperature protection device is connected to the driving chip, and the other side is connected to the LED lamp.

[0005] According to an embodiment of the present invention, the temperature operating range of the negative temperature coefficient sensor is -40-125°.

[0006] According to an embodiment of the present invention, the driving chip is connected in series with the LED lamp.

[0007] Compared with the prior art, the present application can obtain the following technical effects:

[0008] 1) By setting up an over-temperature protection device, the temperature of the LED is sensed by a negative temperature coefficient sensor. When the temperature of the LED rises, the resistance of the second resistor will decrease accordingly, thereby shutting off the current and achieving over-temperature protection.

[0009] Of course, any product implementing the present utility model does not necessarily need to achieve all of the above technical effects at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0011] Figure 1 Schematic diagram of an LED protection circuit for a vehicle lamp according to an embodiment of the present application.

[0012] Figure ID

[0013] A driving chip 10 , a first capacitor 20 , a first resistor 30 , a first diode 40 , an LED lamp 50 , an over-temperature protection device 60 , a negative temperature coefficient sensor 61 , a second resistor 62 , a second diode 63 , and a third resistor 64 . DETAILED DESCRIPTION

[0014] The following will describe the implementation methods of the present application in detail with the help of accompanying drawings and examples, so that the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0015] Please refer to Figure 1 , Figure 1 Schematic diagram of an LED protection circuit for a vehicle lamp according to an embodiment of the present application. As shown in the figure, an LED protection circuit for a vehicle lamp comprises: a driver chip 10, a first capacitor 20, a first resistor 30 and a first diode 40 are connected in series in sequence on the left side of the driver chip 10, an LED lamp 50 is connected on the upper right side of the driver chip 10, and the driver chip 10 and the LED lamp 50 are connected in series; an over-temperature protection device 60 is arranged on the lower right side of the driver chip 10, the over-temperature protection device 60 comprises a negative temperature coefficient sensor 61, a second resistor 62, a second diode 63 and a third resistor 64, the temperature range of the negative temperature coefficient sensor 61 is -40-125°, the negative temperature coefficient sensor 61 is connected in series with the second resistor 62 and the second diode 63, the third resistor 64 and the negative temperature coefficient sensor 61 are connected in parallel with the second resistor 62 and the second diode 63, one side of the over-temperature protection device 60 is connected to the driver chip 10, and the other side is connected to the LED lamp 50.

[0016] In the embodiment of the utility model, the driver chip 10 is specially designed for high-power LEDs, and is connected to a first capacitor 20, a first resistor 30, and a first diode 40 to provide a constant current output channel and a high output current capability. The current output range is from 50 mA to 1,200 mA, which is used to control the brightness of the LED.

[0017] Furthermore, by using the negative temperature coefficient sensor 61 to sense the temperature of the LED, when the temperature of the LED increases, the resistance of the second resistor will decrease accordingly, thereby shutting off the current to achieve overheat protection.

[0018] The above description shows and describes several preferred embodiments of the present application, but as before, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the present application through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present application, and shall be within the scope of protection of the claims attached to the present application.

Claims

1. An LED protection circuit for a vehicle lamp, characterized in that: include: A driver chip, wherein a first capacitor, a first resistor and a first diode are connected in series in sequence on the left side of the driver chip, and an LED lamp is connected on the upper right side of the driver chip; An over-temperature protection device is arranged on the lower right side of the driving chip, and the over-temperature protection device includes a negative temperature coefficient sensor, a second resistor, a second diode and a third resistor. The negative temperature coefficient sensor is connected in series with the second resistor and the second diode, and the third resistor is connected in parallel with the negative temperature coefficient sensor, the second resistor and the second diode. One side of the over-temperature protection device is connected to the driving chip, and the other side is connected to the LED lamp.

2. The LED protection circuit for vehicle lamps according to claim 1, characterized in that: The negative temperature coefficient sensor has a temperature range of -40-125°.

3. The LED protection circuit for vehicle lamps according to claim 1, characterized in that: The driving chip is connected in series with the LED lamp.

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