LED backlight driving circuit, driving method and liquid crystal display device

Abstract

The invention discloses an LED backlight driving circuit, a driving method and a liquid crystal display device. The LED backlight driving circuit comprises an LED light bar and a driving module of the LED light bar; the driving module comprises a backlight driving chip used for adjusting output voltage of the driving module, the backlight driving chip comprises a first comparator used for correcting the output voltage of the driving module, and an output end of the LED light bar is coupled to an inverted input end of the first comparator; a non-inverted input end of the first comparator is coupled to a protection module; and the protection module comprises a detection unit used for detecting output current of the driving module. When a current value detected by the detection unit is higher than a preset first current value, the protection module outputs first reference voltage to the non-inverted input end of the first comparator; and when the current value detected by the detection unit is lower than the preset first current value, the protection module outputs second reference voltage lower than the first reference voltage to the non-inverted input end of the first comparator. The LED backlight driving circuit, the driving method and the liquid crystal display device have the advantage that the efficiency of the driving module is improved.

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 driving method and a liquid crystal display device. Background technique [0002] Most existing liquid crystal display devices use LEDs as backlight sources. The specific method is to connect multiple LED lights in series to form an LED light bar, and then couple the LED light bar to a booster circuit. see figure 1 , the controllable switch Q of the boost circuit is coupled to a backlight driver chip IC, and the output voltage of the boost circuit can be adjusted according to the duty cycle of the output signal of the drive pin G of the backlight driver chip, thereby realizing the dimming of the LED light bar . If there are multiple LED strips, they can be connected in parallel to the same boost circuit. There is a comparator inside the backlight driver chip, and the output end of each LED light bar is coupled to the inv...

AI Technical Summary

Problems solved by technology

Existing backlight drive modules have problems with poor circuit performance. For example, when the LED light bar is lightly loaded (the brightness of the LED light bar is low), it still outputs a large voltage, resulting in a decrease in the efficiency of the backlight drive; or when the LED light bar is heavily loaded ( When the LED light bar brightness is high), the output voltage is low, and the LED light bar cannot reach the expected brightness

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