Optimized single-stage single-switch electronic ballast for Compact Fluorescent Lamp

In this paper a single-stage single-switch electronic ballast for Compact Fluorescent Lamp (CFL) with high input power factor (PF) and low output crest factor (CF) has been proposed. The proposed topology is based on SEPIC converter as a Power Factor Correcting (PFC) stage merged in to a current source resonant inverter. Inductors PFC and resonant inverter are combined in a common core without any impact on each other. In this manner, the ballast will achieve great advantages of reduced cost, size and weight without any effect on circuit performance. If has made the proposed ballast so desirable for CFL application. The analysis and design procedure of the proposed circuit and combination of inductors in a single core has been explained. A laboratory prototype for 42W CFL has been made to explore the validity of analysis and design. The experimental results showed high compliance with expected results of theoretical analysis.