Characterization of an active clamp flyback topology for power factor correction applications

Flyback derived power convertor topologies have long been attractive because of their relative simplicity when compared with other topologies used in low-power applications. Incorporation of active clamp circuitry provides the additional benefit of recycling transformer leakage energy while minimizing switch voltage stress. This paper presents the analysis, design, and experimental results of 500 W single stage and 600 W interleaved active clamp flybacks used for power factor correction. Several practical issues, including the application of charge control, the use of mixed power devices, and a solution to the hold-up time problem are discussed and experimentally verified