Multi-Lamp High-Power-Factor Electronic Ballast Using a Fixed-Frequency Self-Oscillating Driver

This paper presents a fixed-frequency self-oscillating high-power-factor electronic ballast supplying four independent lamps. The fixed-frequency self-oscillating driver is achieved adding a LC series filter supplying a small resistor. The primary winding of the self-oscillating transformer is the series inductor of the filter. So, if one or more lamps are damaged, the switching frequency will not change. To achieve the power-factor-correction, it is used a passive method, based on a modified valley-fill filter. In order to prove the proposed idea, it is shown the simulation and experimental results of the self-oscillating electronic ballast supplying four independent lamps. Key-Words: Multi-Lamp, High Power Factor, and Self-Oscillating.