A 40 V 10 W 93%-Ef ficiency Current-Accuracy- Enhanced Dimmable LED Driver With Adaptive Timing Difference Compensation for Solid-State Lighting Applications Dongkyung Park, Zhidong Liu , Student Member , IEEE,a n d H o iL e e, Senior Member , IEEE

Abstract

This paper presents a floating-buck dim mable LED driver for solid-state lighting appl ications. In the proposed driver, an adaptive timing difference compensation (ATDC) is developed to adaptively adjust the off-time of the low-s ide power switch to enable the driver to achieve high accuracy of the average LED current over a wide range of input voltages and number of output LED loads, fast settling time , and high operation fre- quency. The power ef ficiency bene fits from the capabilities of using synchronous recti fier and having no sensing resistor in the power stage. The synchronous rec tification under high input supply voltage is enabled by a prop osed high-speed and low-power gate driver with pseudo-digital level shifters. Implemented in a 0.35 m 50 V CMOS process, experime ntal results show that the proposed LED driver can operate at 1 MHz and achieve peak power ef ficiency of 93% to support a wide range of series-con- nected output LEDs from 1 to 10 and a wide input range from 10 to 40 V. The proposed LED driver has only 2.8% current error from the average LED current of 345 mA and settles within 8.5 s after triggering the dimmi ng condition, improving the settling time by 14 times compared with the state-of-the-art LED drivers.