Single-stage electronic ballast with Class D and Class E rectifiers as line-current shaper

New single-stage high-power-factor electronic ballast is proposed. Class D and Class E rectifiers are inserted between the bridge rectifier and the bulk filter capacitor to increase the conduction angle of the bridge-rectifier diodes for reducing line current harmonics. The Class D rectifier connected in parallel with the fluorescent lamp. The Class E rectifier is driven by a high-frequency near sinusoidal current source. A prototype for a 32-W fluorescent lamp was built and tested. At full power, the THD_i was 23.5%, the power factor was 0.97 and the efficiency was 90.9%. The lamp-current crest factor was about 1.53.