This paper describes a self-oscillating electronic ballast, having fixed switching frequency, to supply four independent fluorescent lamps, with high power factor. To provide the power factor correction it was studied the modifications of the valley-fill filter, presented in the literature, choosing one that meets the IEC 61000-3-2 Class C requirements, about the input current distortion. To drive the switches it was proposed a modification at the conventional self-oscillating driver, novel in the literature, making it independent on the load of the ballast. So, it is built up the prototype and showed the experimental results.
Self-oscillating driver; valley-fill filter; high power factor; multi-lamp operation
