Single switch, unity power factor, lamp ballasts

Unity power factor, single active switch AC-to-AC power converter topologies based on proper integrations of automatic current shapers and single switch inverters such as Class E power converters are presented, which are suitable for lamp ballast applications. Descriptions of desirable mode of operations and the first order analysis are given. The proposed ballasts have the following salient features: unity input power factor and low crest factor lamp current; single active switch reducing circuit complexity; and lossless switching, all of which are verified by experimental results