A Boost-Buck LED driver with Power Factor Correction

This paper demonstrates a buck-boost LED driver in 0.18-㎛ BCDMOS technology. The LED driver is designed to operate in AC input voltage. It has a boost-buck cascaded structure. The boost converter is suitable to correct power factor operating in continuous conduction mode(CCM). And the buck converter regulates the LED current to keep constant brightness of LED. The LED driver achieves power factor of 0.988 and efficiency of 57.8%.