Cost-Effective LED Dimming Driver With Single Chip Design for Smart Lighting System

Abstract

For smart lighting system, this paper presents a high-power (60V/1A) single-chip driver for LED dimming using TSMC high-voltage process. The main circuit included analog circuit, power driver and digital control circuit with mixing-mode design methodology. The proposed digital dimming controls LED brightness increasing or decreasing with only two switches. The switches can be controlled by the auto mode or manual mode for user selection. All digital control circuits are embedded to the chip. Because of without the need of micro-processor for LED dimming, this chip is cost-effective design that can save the components of interface. To keep high-stable LED lighting, the dimming techniques used current mode rather PWM (Pulse Width Modulation) to reduce flicker. The multi-level current approach used 16 steps for LED lighting control. The step resolution is 6.25% for smart lighting system. With variable constant current control, this approach can achieve better lighting efficiency, reduce noise radiation and prolong LED lifetime for smart lighting systems. The maximum driving efficiency of the proposed chip can achieve near 98% as driving for 60W LED dimming.