A Kind Of White Led Driver Chip Design

White LED lamps have the advantages of low power consumption, environmental protection and long life.They are widely used in billboards, street lamps, mobile phones, PAD, automotive and other fields. As a new type of green and environmental illumination light source, white LED lamps will replace the traditional lighting system. With the large number of applications of white LED lamps, the corresponding LED driver circuit has been actively studied.Switching power technology used in white LED driver circuit is very common. The principle of the boost converter is analyzed and a type of wide input range white LED driver chip is designed in the thesis. The chip integrates high-voltage power devices and internal control circuit and has two dimming modes:linear dimming and PWM dimming.This thesis designs the overall structure of the chip, and briefly describes each module and the chip pin functions. And then according to the functions of the chip, the sub-modules are designed, which contain power-on reset circuit, undervoltage lockout module, bandgap voltage reference, oscillator, thermal shutdown module, dimming part and buffers, among which the bandgap voltage reference has no amplifier, thus reducing power consumption and the difficulty of design. PWM dimming module is a complement for linear dimming mode. It allows for better control of the LED lights. The buffer is designed with a structure of inverter chain, increasing the external drive capability of the chip.In the thesis, the sub-module circuit and the overall circuit are designed based on the CSMC0.5μm BCD process library and are simulated by HSPICE software. The output voltage of the linear regulator is stable, the temperature coefficient of the bandgap reference is about11.35ppm/℃and the thermal shutdown temperature is about151℃. The simulation results reach the intended targets and meet the design requirements.