A Novel SEPIC Type Single-Stage Single Switch Electronic Ballast with Very High Power Factor and High Efficiency

A novel SEPIC type single-stage single switch electronic ballast with very high power factor is presented in this paper. The proposed lamp power circuit combines the SEPIC converter and a single switch resonant inverter to form a single-stage inverter to power the lamp. The resulting circuit provides a compact and cost-effective circuit configuration for electronic ballast designs. By operating the SEPIC power factor corrector in discontinuous conduction mode, the average line current is in phase with the fine voltage and a very high power factor is achieved at the input. In the proposed design, zero-current switching (ZCS) is achieved at the turn-on of the MOSFET to maintain high efficiency for the overall circuit. The proposed topology also allows simple gate driver to be used without the use of any isolation devices. Simulation and experimental results are provided for a design example of a 26W compact fluorescent lamp to verify the feasibility of the proposed circuit.