Bridgeless ZETA PFC converter for low voltage high current LED driver

This paper deals with power factor correction (PFC) in low voltage high current (LVHC) multi-string light emitting diode (LED) using a bridgeless (BL) ZETA. This application is designed for large area LED lighting with illumination control. A multi-mode LED dimming technique is used for lighting control. The BL-ZETA PFC converter feeds power to isolated flyback DC-DC converter. The regulated low voltage from flyback converter is a source power to the synchronous buck converters for multi-string LED driver and forced cooling system for LED junction. The BL-ZETA PFC converter inductor design is based on discontinuous inductor current modes (DICM) which provide good PFC at low cost. The proposed LED driver is designed and developed with hardware test results. The critical parameter of the LED driver is tested and measured at full load with dimming control capability for universal input AC (90–265 V). The total harmonic distortion (THD) is observed lesser than the IEC 61000-3-2 Class C harmonic limits.