This paper presents a simple alternative of electronic ballast operating in self-sustained oscillating mode with dimming capability for fluorescent lamps. A simple modification in the gate driver circuit allows the lamp to dim without compromising the simplicity, reliability, and low cost which characterize the self-oscillating electronic ballast. A qualitative analysis is presented to explain the behavior of the proposed self-oscillating electronic ballast with dimming feature. In addition the stability and the key equations for the design are derived using the extended Nyquist criterion and describing function method. Experimental results are presented to demonstrate the performance and to validate the analysis carried out.
Self-oscillating; electronic ballast; fluorescent lamps; dimming
