Highly accurate average current controller using charge sharing method for LED lamp driver

Abstract

An average current controller (ACC) that can accurately regulate the light-emitting diode (LED) forward current for lighting applications is proposed. The proposed ACC employs a charge sharing method to achieve a highly accurate average LED forward current by compensating for an error occurred when the LED forward current is sampled. It was fabricated using a 0.35 mu m CMOS process technology and occupied a small chip area of 1028 mu m x 728 mu m. The measurement results showed that the proposed ACC achieved a deviation in the average LED forward current of < 0.6% over the entire input voltage range while achieving a maximum power efficiency of 93.6%. Therefore, the proposed ACC is suitable for high-quality LED lighting systems requiring an accurate LED forward current.