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The analysis and design of a dimmable electronic ballast based on the class E amplifier and fed from solar cells with 12V backup batteries is described. The class E amplifier uses a capacitive impedance inverter as resonant tank and one diode antiparallel with the switch; these elements allow implementation of a dimming feature for the ballast and ignition of the lamp while maintaining zero voltage commutations in the switch. The designed electronic ballast drives a 21W lamp and operates at a switching frequency of 370kHz. Dimming is implemented using an SG3524 in a voltage-controlled oscillator fashion. [ABSTRACT FROM AUTHOR]

In this paper, a single-stage high-power-factor high-efficiency electronic ballast for compact fluorescent lamps is presented. The proposed topology uses two voltage sources connected in series to feed the inverter ballasting the lamp, one of them consists in the rectified line voltage and the other in a dc-dc converter operating in discontinuous conduction mode. In this way, the converter processes a lower energy than the nominal power of the lamp. The proposed topology presents simplicity, high-power-factor, low current crest factor, and high efficiency. [ABSTRACT FROM AUTHOR]