A single stage optocoupler-less buck-boost PFC driver for LED lamp at universal AC mains

This paper deals with a single-stage PFC (Power Factor Corrected) buck-boost converter based low power LED (Light Emitting Diode) lamp driver for general purpose lighting. In the proposed circuit, a buck-boost converter is operated in CCM (Continuous Conduction Mode) with PSCR (Primary Sensing Current Regulation) using feed forward current control scheme to improve power quality at universal AC mains. A design procedure of proposed LED driver is illustrated and its simulated performance is demonstrated for improvement in various power quality indices in Matlab/Simulink environment for a 220 V, 50 Hz input AC mains. In order to validate the design, an optocoupler-less buck-boost PFC converter based LED driver is developed with low component count and low cost and tested for a load of 13 W with multiple LEDs connected in series. Each LED has a forward voltage of 3.1 V, forward rated current of 325 mA and power rating of 1 W. The measured power quality indices are observed well within the IEC-61000-3-2 norms for class C equipments.