An electronic ballast with wide dimming range, high PF, and low EMI

Abstract

The authors describe an electronic ballast design with the capability of low radiated and conducted EMI over a wide dimming range. It overcomes some limitations of traditional electronic ballasts that use frequency variation for dimming control. The proposed design allows soft switching of the ballast from full-power operation down to less than 10% power. Low-cost and low-voltage power metal oxide semiconductor field effect transmitters (MOSFETs) can be used in the proposed dimmable electronic ballast. The design approach is described and implemented successfully in a 2/spl times/36 W fluorescent lamp system.