A single-stage dimmable electronic ballast with high power factor

A novel fixed frequency electronic ballast that consists of a single-stage asymmetrical half-bridge inverter, a load resonant tank and a switched-capacitor dimming control circuit is proposed for driving fluorescent lamps. High efficiency and unity power factor are achieved by the proposed single-stage topology. The switched-capacitor dimming control technique in the studied high frequency electronic ballast provides better EMI features. The steady-state operating principle and design procedure for the proposed single-stage dimmable electronic ballast are analyzed and discussed in detail. A ballast prototype was implemented at the laboratory. The experimental results verify the feasibility of the proposed method.