Backlight drive circuit

Abstract

A backlight drive circuit comprises an LED light bar, an LED driving chip used for outputting a backlight current to drive the LED light bar; a temperature detection circuit used for detecting the temperature of the LED light bar and outputting a sampling voltage; a comparison circuit used for generating a control signal according to the sampling voltage and a reference voltage; a reference current generating circuit used for adjusting a reference cureent of the LED driving chip according to the control signal, wherein the LED driving chip is also used for adjusting the backlight current of the LED light bar according to the reference current. According to the backlight drive circuit provided by the present invention, by using a thermistor temperature detection circuit arranged on the LED light bar to output the sampling voltage, controlling the reference current of the LED driving chip according to the sampling voltage and the reference voltage, and further regulating and controlling an output current of the LED driving chip according to the current temperature, the LED light bar keeps working with the backlight current matching the current temperature during the temperature change process.

Description

technical field [0001] The present invention relates to the field of display technology, and more particularly, to a backlight driving circuit. Background technique [0002] A liquid crystal display (LCD, Liquid Crystal Display) has many advantages such as a thin body, power saving, and no radiation, and has been widely used. Most of the liquid crystal display devices currently on the market are backlight liquid crystal display devices, which include a liquid crystal panel and a backlight module. The working principle of the liquid crystal panel is to place liquid crystal molecules between two parallel glass substrates. There are many vertical and horizontal small wires between the two glass substrates. The direction of the liquid crystal molecules is controlled by electrifying or not, and the light of the backlight module is refracted. Come out to generate the picture. Since the liquid crystal panel itself does not emit light, the light source provided by the backlight mo...

AI Technical Summary

Problems solved by technology

[0005] like Figure 2a As shown, the LED light bar 11 is close to the reflector or the light guide plate and other components 20, and the temperature of the LED light bar 11 rises after being lit by the LED driver chip 12, especially when the ambient temperature is high, it may exceed the reflector or the light guide plate. The temperature resistance value of components 20 such as light boards, and then problems such as deformation and damage occur (such as Figure 2b shown)

[0006] However, when adjusting the brightness of the backlight, especially when the ambient temperature is high, the LED light bar 11 will generate heat, which will cause the operating temperature of the liquid crystal display device to be too high, causing problems such as deformation and damage of the reflective sheet or the light guide plate, etc.

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