Abstract
Analysis, design and practical consideration of a single-stage electronic ballast with dimming feature and unity power factor are presented in this paper. The proposed single-stage ballast is the combination of a boost converter and a half-bridge series-resonant parallel-loaded inverter. The boost semi-stage working in the discontinuous conduction mode functions as a power factor corrector and the inverter semi-stage operated above resonance is employed to ballast the lamp. Replacing the lamp with the plasma model, analysis of the ballast is fulfilled. The dimming feature is carried out by using pulse-width modulation and variable-frequency controls simultaneously. The proposed ballast can save a controller, reduce size and possibly increase system reliability over a conventional two-stage system. A prototype was implemented to verify the theoretical discussion. The hardware measurements have shown that the desired performance can be achieved feasibly.