BACKLIGHT DRIVING CIRCUIT AND LIQUID CRYSTAL DISPLAY WITH THE SAME

摘要

A backlight driving circuit is disclosed. The backlight driving circuit includes a steady voltage circuit, a boost converter, a current setting circuit, and a control circuit. The steady voltage circuit receives an input voltage, filters the input voltage and outputs a steady DC voltage. The boost converter connects to the steady voltage circuit to receive the steady DC voltage. The control circuit provides a first PWM square wave such that the boost converter may supply power to the LED light bar. Wherein the boost converter includes a first MOSFET or a triode. At least three parallel connected resistors are arranged between a source of the first MOSFET or a collector of the triode and the ground, and the three resistors have the same or similar resistance. In addition, a liquid crystal display includes the backlight driving circuit is also disclosed.

主权项

1. A backlight driving circuit, comprising:
a steady voltage circuit for receiving an input voltage, filtering the input voltage and outputting a steady DC voltage; a boost converter connecting to the steady voltage circuit and to the positive end of a LED light bar, the boost converter receives the steady DC voltage, increases the DC voltage and outputs the DC voltage to the LED light bar; a current setting circuit connecting to a negative end of the LED light bar for setting a current of the LED light bar; a control circuit for providing a first pulse-width-modulated (PWM) square wave for the current setting circuit and providing a second PWM square wave for the boost converter; and wherein the current setting circuit includes a first MOSFET Q1 or a triode, at least three parallel connected resistors are arranged between a source of the first MOSFET or a collector of the triode and the ground, and the three resistors have the same or similar resistance.