A Highly Power-Efficient LED Backlight Driving System for LCD TVs

A highly power-efficient light-emitting diode (LED) backlight driving system for liquid crystal display televisions (LCD TVs) to optimize the output voltage of boost converter is proposed. To optimize the output voltage, the forward voltage of each LED channel is analyzed and the turn-on sequence of LED channels is rearranged according to the forward voltages of LED channels. As a result, the output voltage tracks the required output voltage to drive target current in each LED channel. Experimental results show that the improvement of power efficiency is 3.8% in the proposed LED backlight driving system with 1% on-duty ratio of the pulse width modulation (PWM) signal and 5 V forward voltage variation of LED channels