Difference-integral dimming controller for the single-stage back-lighting electronic ballast

This paper proposes a novel difference-integral controller (DIC) to improve the dimming performance of variable-frequency single-stage electronic ballast for cold cathode fluorescent lamp. The proposed DIC will linearize the dimming process by linear integral behavior. The half-bridge resonant inverter is employed in the presented back-light system. This system also incorporates a voltage feed-forward control to eliminate unstable illumination and to provide excellent step response. Complete analysis and design considerations are discussed in detail in this paper. The measured results obtained from experiments are close to the theoretical prediction. The overall efficiency of the proposed system is promoted above 91%.