A high power factor flyback-half-bridge electronic ballast with dimming feature

This paper presents the analysis, design and practical considerations of a high power factor single stage electronic ballast with dimming feature for fluorescent lamps. The proposed topology is the combination of a flyback converter and a half-bridge series-resonant parallel-loaded inverter. The high power factor is guaranteed by the use of a flyback converter operating in discontinous-conduction mode. The high-frequency supply of the lamp is given by the half-bridge converter. The driver circuit is made with the self oscillating half-bridge driver IR2151. In spite of its simplicity, a high performance concerning load and supply is achieved, ensuring a sinusoidal and in-phase supply current.