LED (Light Emitting Diode) backlight drive circuit, backlight module and liquid crystal display device

Abstract

The invention discloses an LED (Light Emitting Diode) backlight drive circuit, a backlight module and a liquid crystal display device. The LED backlight drive circuit comprises an LED light bar and a constant current chip which controls current flowing through the LED light bar. The LED backlight drive circuit is further provided with a comparison module which collects the output end voltage of the LED light bar. When the output end voltage of the LED light bar is higher than the reference voltage, the comparison module controls the constant current chip to cut off the current of the LED light bar. As the comparison module is adopted, when the LED of the LED light bar is short-circuited, the output end of the whole LED light bar is raised. When the comparison module detects that the current at the output end of the LED light bar exceeds the reference voltage, the constant current chip is controlled to cut off the current of the LED light bar, that is, a power supply of the backlight module is cut off. Therefore, LED short trouble protection is realized, and the constant current chip and an associated circuit board are prevented from being further damaged.

Description

technical field [0001] The invention relates to the field of liquid crystal display, and more specifically relates to an LED backlight driving circuit, a backlight module and a liquid crystal display device. Background technique [0002] A liquid crystal display device includes a liquid crystal panel and a backlight module for providing a light source for the liquid crystal panel. As the cost of LEDs decreases, most existing backlight modules use LEDs as light sources. The backlight module with LED as the light source generally connects multiple LEDs in series to form a light bar, and then uses a booster circuit to drive the light. The output terminal of the LED is connected in series with a MOS tube. By controlling the duty cycle of the tube, the effective current flowing through the LED strip can be controlled, so as to achieve the purpose of dimming. When an LED in the LED light bar is abnormally short-circuited, the brightness of the entire LED string will become lower,...

AI Technical Summary

Problems solved by technology

When an LED in the LED light bar is abnormally short-circuited, the brightness of the entire LED string will become lower, but at this time the constant current chip will not turn off the current of the LED light bar, which not only reduces the viewing comfort of the user, but also affects the constant Flow chips and related circuit boards have a certain impact

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