Universal input voltage range self-oscillating electronic ballast with power factor correction

This paper presents the analysis and design of a self-oscillating electronic ballast with universal input voltage range (100-240 V_RMS) and power factor correction to supply a T8 32 W fluorescent lamp. The power factor correction stage consists of a DC-DC converter operating in discontinuous conduction mode. The lamp is supplied by a half-bridge resonant inverter and a self-oscillating command circuit is used in both power factor correction and inverter stages. Universal input voltage is performed using an auxiliary circuit that controls the duty-cycle of the DC-DC converter. Experimental results are presented in order to demonstrate the feasibility of the proposed electronic ballast presenting high power factor (0.99), low total harmonic current distortion (14%) for the entire input voltage range.