Single-stage high-power-factor electronic ballast for fluorescent lamps

A Single-stage high-power-factor electronic ballast for fluorescent lamps is proposed. The ballast offers a high power factor and a high-frequency voltage to the lamp. It is obtained by combining a power factor correction stage and an inverter stage based on the half-bridge topology. A saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. The proposed ballast has high energy efficiency, low cost, and high reliability compared to the conventional electronic ballasts. Experimental results obtained on a 30W fluorescent lamp are discussed.