Patent ID: 7002547
Filing Date: 2006-02-21
Classification: G09G,H05B,Y02B

Abstract:
1. A backlight control device for a liquid crystal display that is a transmissive type or a transreflective type liquid crystal display equipped with an LED as a backlight, comprising: an LED driving circuit that is connected to a power supply circuit and drives the LED; and a current control device that detects brightness around the liquid crystal display and controls a driving current for the LED according to the detection, wherein the current control device is equipped with a control reference voltage generation device that generates a control reference voltage according to brightness around the liquid crystal display, and an error amplifier circuit that generates a signal representing a difference between a detection voltage according to the drive current of the LED and the control reference voltage generated by the control reference voltage generation circuit, and the power supply circuit varies an output voltage thereof according to an output of the error amplifier circuit.