A 40V 10W 93%-efficiency current-accuracy-enhanced dimmable LED driver with adaptive timing difference compensation for solid-state lighting applications

Abstract

This paper describes a floating buck dimmable LED driver for solid-state lighting applications. Adaptive timing difference compensation is proposed to enable the driver to achieve high accuracy of the average LED current, fast settling time, and high-frequency operation over a wide range of input voltages and number of LED loads. The power efficiency of the proposed LED driver is benefited from the capabilities of using synchronous rectification and having no sensing resistor in the power stage. The synchronous rectification under high input supply voltage is enabled by a proposed high-speed and low-power gate driver with pseudo-digital level shifters. Implemented in a 0.35μm 50V CMOS process, the proposed 40V LED driver can operate at 1MHz and achieve 93% peak power efficiency when driving up to 10 series-connected LEDs. It has only 2.8% current error from the average LED current of 345mA and settles within 8.5μs under different line and load variations. The performances of the proposed driver significantly outperform all state-of-the-art counterparts.