Design Of A New White LED Backlight Diver IC

White LED has become one of the highest quality backlight of the portable electronic products in recent years for its green, low energy consumption, high efficiency and long useful life. As a bridge which connects the voltage supply and lighting equipment, the driver chip is an indispensable part in the white LED backlight system. As a result of the rapid development of the electronic products, with the higher requirements to the efficiency, stability and compatibility.. White LED backlight driver chip based on the traditional mode can no longer meet the requirements of the consumers today.In this article, a new mode white LED backlight driving application specific chip for constant current output based on charge pump is proposed. Firstly, the overall framework of the chip system is constructed and the scope of work and performances of the chip are proposed. After that, the reference module, the over-temperature protection module, the oscillator module, the charge pump module, the logic control module and the LED driving module are designed. For the reference module, bootstrap and temperature compensation are used to produce stable bias current and reference voltage. For the charge pump module, to significantly increase in the efficiency, reforming in the structure of traditional 1X/1.5X/2X charge pump circuit. And driving with the high-precision current matching technology is in the LED driving module to substantially reduced in the output current error.The simulation results are given. Then, simulating to the crucial parameters by using the Synopsys Hspice simulation software with the CSMS 0.5uM model, and then, using Cadence's Virtuoso for chip design and verification.The chip made by the tape-outing is tested, the result show that, the standard output current of is 80mA, the maximum output current is 124mA and the shutdown current is 0.36uA,output current error between channels is 0.5%, output current error between chips is 0.8%, and the efficiency of the chip is 92%. The simulation and the practical tests illustrate that the designed white LED backlight driving application specific integrated chip has achieved the desired technical requirements.