A single-stage electronic ballast with power factor correction and low crest factor for fluorescent lamps

A new single-stage power factor correction electronic ballast using the charge pump concept is proposed in this paper. Circuit derivation, principle of operation and the conditions for achieving unity power factor are discussed. The proposed electronic ballast is implemented and tested. It is shown that 0.987 power factor, 13% THD, and 1.6 crest factor can be obtained with two 40-watt fluorescent lamps in series. The lamp power variation range is automatically limited within ±15% for ±10% line input voltage variation without any feedback control, and the maximum DC bus voltage across the bulk capacitor during the preheat and start-up modes is less than 415 V for 220 V line input so that a 450 V rated bulk capacitor can be used