Active-clamp DC/DC converters using magnetic switches

Although DC/DC converters with coupled inductors can provide high voltage gain to meet the requirements of many emerging applications, their efficiency is degraded by losses associated with the leakage inductors, The active-clamp technique recycles the leakage energy, but at the price of increasing topology complexity, A family of high-efficiency, high step-up DC/DC converters is proposed in this paper. The proposed converters, which use diodes and coupled windings instead of active switches to realize clamp functions, present better performance than their active-clamp counterparts. The efficiency of a 35W front-end converter for high intensity discharge lamp ballast is higher than 90% with 12V input and 100V output, The high efficiency is achieved because the leakage energy is recycled and the switch voltage stress is minimized.