LED Driver Based on Boost Circuit and LLC Converter

In order to reduce the size and cost of a medium-power light-emitting diode (LED) driver, a novel single-stage LED driver integrating a boost converter with a half-bridge LLC resonant converter has been proposed. This topology is composed of a boost power factor correction circuit operating in a discontinuous conduction mode and an isolated LLC circuit unit with soft-switching characteristics. The proposed LED driver only adopted two switch components, thus benefiting from control simple and without employing an extra switch driver and a control circuit. The operating principle and characteristics of the proposed LED driver are analyzed in detail. In addition, experimental results of a laboratory prototype for supplying a 100-W/70-V LED lighting systems from 220-V/50-Hz ac line voltage are presented to verify well the correctness of the theoretical analysis and parameters’ design.