Design and Implementation of Dimmable Electronic Ballast Based on Integrated Inductor

This paper presents an implementation of integrated inductor for typical dimmable electronic ballasts having two power processing stages. The inductor used in the front-stage power factor corrector is integrated with the resonant inductor in the output-stage of the ballast inverter, so that the usage of the magnetic core material, and thus the cost, can be reduced. Existing circuit schematic can be retained without requiring any modification. Most importantly, the ballast performance is similar to the original design with two separate inductors. Based on using a z-parameter gyrator-capacitor model, modeling, design, and analysis of the ballast operation will be presented. A comparative study of using two separate inductors and integrated-inductor designs on the core volume, conduction and hysteresis losses, inductor current waveforms, input current harmonics, output lamp crest factor, overall efficiency, and costing will be carried out. Simplified design procedures will be given. The structure has been successfully applied to a 36-W prototype