Half-bridge power converter for driving LED by series-resonant connection of inductor, inductor and capacitor

摘要

Disclosed herein is an LLC half-bridge power converter for driving an LED, which uses a CMOS timer IC having 50% duty cycle and a usable frequency range of 50 KHz through 1 MHz as a controller. In the LLC half-bridge power converter for driving an LED, the output of a rectifier is detected to operate an opto-coupler according to a soft-start set value and the opto-coupler is controlled to be turned off when the output of the rectifier exceeds a set rated voltage. The capacitance of a frequency varying condenser of the controller is varied by the opto-coupler to change the frequency of the controller so as to rapidly stabilize the output level and maintain a desired output level.