A constant power single-switch electronic ballast with power factor correction

Compact fluorescent lamps (CFL) suffer two major drawbacks: (1) they are unable to achieve high power factor; (2) they are unable to maintain the same amount of brightness under fluctuating line voltage. This paper proposed a simple control method for a high power factor single switch electronic ballast that has the ability to maintain constant lamp power at its full power condition and it is dimmable with phase-cut dimmers. By controlling the DC-link power at the DC-link capacitor of the power circuit using duty ratio control, the intensity of the lamp´s brightness is maintained at a relatively steady level at its full power condition when the input voltage varies. When a phase-cut dimmer is used for dimming, the control circuit fixes the duty ratio of the power circuit. The description of the proposed solution is provided in this paper. Experimental results are provided to highlight the merits of the proposed work.