Multi-channel LED Driver with PWM Dimming and Temperature Self-Protection

Abstract

In this paper, we propose a novel LED driver chip for multi-channels based on current mirrors. The driver can change the LED brightness with a pulse width modulation (PWM). The chip built a four-order temperature sensor for chip protection. The chip is implemented with TSMC 0.25 UM CMOS HIGH VOLTAGE MIXED SIGNAL BASED. Using 60V power MOS for two channels LED driver, this chip can drive 120W LED string for smart street lighting. The chip core occupied about 1215um x 900um silicon area. The driving efficiency can achieve up to near 90%.