Single-switch electronic ballast with continuous input current charge pump power-factor correction

This paper presents a single-switch electronic ballast with continuous input current charge pump power-factor correction. The ballast circuit is composed of a series/parallel inverter, a charge pump power-factor corrector, and a dimming controller. The characteristics and design considerations of this ballast are discussed in this paper. Dimming control is achieved by varying the switching frequency. The frequency-modulation scheme is used to reduce the low-frequency output current ripple. A prototype of a 36WT8 fluorescent lamp ballast has been implemented and tested. Experimental results verify the analytical derivations.