A Novel Single-Stage Constant-Wattage High-Power-Factor Electronic Ballast

A novel single-stage high-power-factor electronic ballast is presented in this paper. The ballast is obtained from the integration of a buck-boost converter and a half-bridge LC resonant inverter. The ballast features lamp power regulation against line voltage fluctuations together with high power factor and dimming capability. The steady-state analysis of the ballast is performed and a low-frequency model of the input stage is derived. A design example, including closed-loop circuitry, is also presented. Finally, some experimental results from a laboratory prototype are shown. Index Terms-- Constant-wattage feature, fluorescent lamps, high-frequency operation, power-factor correction, single-stage ballast.