Chip implementation of high-efficient light-emitting diode dimming driver for high-power light-emitting diode lighting system

This study presents a novel high-power light-emitting diode (LED) driver based on chip-level design. We propose a multi-level current approach to LED dimming, rather than pulsed current. The LED driving current can be controlled directly using a digital interface, making it more user-friendly. An analysis of output impedance and driving current demonstrates how the driver can be realised on a single chip. A prototype chip was designed using the second generation TSMC 0.25 mu m high-voltage technology. The chip area, including I/O pads and power driver, is only 0.89 mm(2). The proposed chip is able to drive a 60 W LED panel at maximum output by regulating current in 16 steps for LED dimming. Measurement results indicate that driving efficiency reaches 96% and lighting efficiency is 20% higher than that achieved using pulsed-width modulation. Furthermore, the proposed chip is able to reduce interference, improve lighting efficiency, and prolong the lifespan of LED devices.