Low-cost electronic ballast to supply MH lamps based on flyback converter

A novel electronic ballast to supply metal-halide lamps is presented. The circuit is based on a flyback converter operating in discontinuous-conduction-mode. To avoid acoustic resonances, the lamp is supplied by a low-frequency square-waveform current, using a half-bridge as inverter. A design example and experimental results are presented in order to validate the proposed topology.