A simple electronic ballast with high power factor for metal halide (MH) lamps

An one-stage electronic ballast for metal halide lamp is presented. Employing an AC/AC regulator with hysteresis current control, the proposed ballast performs power regulation and power factor correction in one stage. The circuit is controlled in an approximately constant power mode to keep the input power almost unchanged. The lamp is operated under low frequency and no acoustic resonance occurs. The paper presents the topology, operation, design, simulation, and experimental results from a 70 W prototype.