(A) study on new high power factor high efficiency electronic ballast for metal halide lamp

Abstract

A new electronic ballast circuit for Metal Halide Lamp is suggested. It operates at 20 kHz resonant frequency and adopts zero voltage switching scheme in which the switching element switches at the voltage zero crossing point. In addition, it also adopts the self-oscillation control scheme for base drive with no additional base drive and controller. These guarantees that the ballast becomes smaller and lighter, and has little acoustic noise, low EMI, and reliable operation, as well. Furthermore, it has almost unity input power factor. These features are verified through analysis and experiment.