A high-power-factor LED driver with zero-voltage switching-on characteristics

This paper proposes a high-efficiency LED driver consisting of interleaved buck-boost and buck converters. With no need to use any auxiliary reactive components, the active switches can operate at zero-voltage switching on (ZVS). The buck-boost converter is operated at discontinuous-conduction mode (DCM) to perform the function of power-factor correction (PFC). The buck converter regulates the output voltage to drive LEDs. A prototype 60-W LED driver is built and tested. Experimental results show that the switching losses can be effectively reduced by operating the active switches at ZVS. The measured power factor and circuit efficiency are as high as 0.99 and 93%, respectively.