A Novel Single-Stage Dimmable Electronic Ballast with High Efficiency and Unity Power Factor Using an Integrated Buck-boost Current Source Resonant Inverter

A novel single stage dimmable electronic ballast with high efficiency using an integrated buck-boost current fed resonant inverter is presented in this paper. A compact lamp power circuit is designed with the proposed resonant inverter has the advantages of reduced circulating current and having easy switch drivers configuration to eliminate the use of isolation devices. The buck-boost stage operating in discontinuous conduction mode (DCM) allows a close to unity power factor to be achieved for different lamp power conditions. A simple variable frequency controller is developed using the modified 555 timer to provide dimming operations. Experimental waveforms are provided to highlight the merits of the proposed circuit on a 42W compact fluorescent lamp.