LED backlight and liquid crystal display device

Abstract

The invention discloses an LED backlight which comprises a boost circuit, N shunt-wound LED strings, a backlight driving integrated circuit, and N control circuits, wherein the boost circuit is used for boosting input DC voltage and outputting the boosted DC voltage; each LED string comprises a plurality of LEDs connected in series and is used for receiving the boosted DC voltage from the boost circuit; the backlight driving integrated circuit is used for controlling the make-and-break of the boost circuit and judging whether other LED strings are closed or not according to that whether the voltage of the negative terminal of any one LED string is zero; and each control circuit controls the voltage of the negative terminal of the LED string corresponding to the control circuit not to be zero so as to enable the backlight driving integrated circuit not to close other LED strings except the LED string. According to the LED backlight provided by the invention, when any one LED string is an open circuit, the backlight driving integrated circuit can not close any other LED strings except the LED string, that the N LED strings are extinguished completely is avoided, and the LED backlight can continue to provide a display light source. The invention further provides a liquid crystal display device provided with the LED backlight.

Description

technical field [0001] The invention relates to the field of liquid crystal display. Specifically, it relates to an LED backlight source and a liquid crystal display device. Background technique [0002] With the continuous advancement of technology, the backlight technology of the liquid crystal display device has been continuously developed. Conventional liquid crystal display devices use cold cathode fluorescent lamps (CCFLs) as backlight sources. However, due to the shortcomings of CCFL backlight such as poor color reproduction ability, low luminous efficiency, high discharge voltage, poor discharge characteristics at low temperature, and long time for heating to reach a stable gray level, backlight technology using LED backlight has been developed. [0003] In the liquid crystal display device, the LED backlight is arranged opposite to the liquid crystal display panel, so that the LED backlight provides a display light source to the liquid crystal display panel, where...

AI Technical Summary

Problems solved by technology

When the backlight driving integrated circuit 130 detects that the negative terminal voltage of a plurality of LEDs in the arbitrary LED string is zero, the backlight driving integrated circuit 130 will control all other LED strings except the arbitrary LED string to be turned off, so that the multiple LED strings 120 are all extinguished, thereby making the LED backlight unable to provide display light source to the liquid crystal display panel, affecting the display of the liquid crystal display device.

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