Patent ID: 8138688

Claim:
An LLC half-bridge power converter for driving an LED, which is configured to generate an output pulse signal from an external input power DC through an output unit ( 110 ) according to frequency control of a controller ( 100 ), resonate the output pulse signal of the output unit ( 110 ) through an LLC resonator ( 120 ), rectify the output pulse signal through a rectifier ( 130 ) at the secondary side of the LLC resonator ( 120 ) to output a DC voltage to a load, detect the output of the rectifier ( 130 ) through a feedback unit ( 140 ) and feed back the output of the rectifier ( 130 ) to the controller ( 100 ), wherein the controller 100 is a CMOS timer IC that has 50% duty and a usable frequency range of 50 KHz through 1 MHz and receives a feedback signal based on a soft-start set value set to the feedback unit ( 140 ) to vary the output frequency thereof according to a capacitance variation of a frequency varying condenser (C 3 ) to control the final output level of the rectifier ( 130 ), and the feedback unit ( 140 ) is configured to detect the output of the rectifier ( 130 ) and operates an opto-coupler according to the soft-start set value, control the opto-coupler to be tuned off when the output of the rectifier ( 130 ) exceeds a set rated voltage and vary the capacitance of the frequency varying condenser (C 3 ) of the controller ( 100 ) according to the opto-coupler.