High-Brightness LED Lighting Driver Design

White LED with its long life, high energy efficient, green and other significant advantages, it shows great potential in market. It is gradually being widely applied to various fields. Because of LED unique I-V curve and temperature characteristics, the sensitivity of LED on the current is higher than that on the voltage, so a dedicated driver chip is needed to make LED work continuously and efficiently.This paper designs an average current mode control LED driver IC operating in a constant off-time mode, compared to the traditional peak current mode control, average current mode control the duty cycle by controlling the average current of the inductor, so the output current can achieve higher current accuracy and slope compensation circuit is not required. As a result of using the 800V depletion UHV NMOS process, the input voltage sources can be powered from 15VDC up to 450VDC. The IC is equipped with a current limit comparator and a timing circuit for hiccup-mode output short circuit protection. Meanwhile, in order to adjust the brightness of LED conveniently, includes a 0-1.5V linear dimming and PWM digital dimming, PWM digital dimming input that can accept an external control signal with a duty ratio of 0-100% and a frequency of up to a few KHz. The chip's of high efficiency, and output current can be programmed between a few mA and up to more than 1A. The chip designs on Cadence platform, and uses Taiwan Nuvoton 800V Depletion UHV NMOS process to implementation.