This Application Note describes the concepts and design of a boost preregulator for power factor correction.This note covers the important specifications for power factor correction, the boost power circuit designand the UC3854 integrated circuit which controls the converter. A complete design procedure is givenwhich includes the tradeoffs necessary in the process. This design procedure is directly applicable to theUC3854A/B as well as the UC3854. The recommendations in Unitrode Design Note DN-39 cover other areasof the circuit and, while not discussed here, must be considered in any design. This application note
upersedes Application Note U- 125 "Power Factor Correction With the UC3854.