高功率因数变换器实现方案

isolated power supply which has inherent acTIve power factor correcTIon (PFC) integrated into the single stage flyback power topology. This power supply is intended for LED lighTIng, white goods, industrial, and other applicaTIons where a high input power factor is required despite the low power output. For example, Energy Star requires PF > 0.9 for commercial lighting applications; and PF > 0.7 for similar residential lighting applications above 5 watts output. In this design example, the power supply output can provide in excess of 750 mA at 12 volts nominal. Other output configurations are possible by merely changing the transformer design (secondary turns) and the output sensing zener diode (Z1).