For decades, and continuing today, the fluorescent lamp has been the cheapest way to produce white light with the minimum amount of energy taken from the mains (lumens/watt). As such, hundreds of millions of compact fluorescent lamps (CFLs) are sold every year, with an ever-increasing demand for higher reliability. Today's lighting systems need ballast control functions to drive compact fluorescent lamps, adding cost and requiring more design time. Also, these functions must often be readjusted for each different lamp type.
Consequently, designers now need solutions that integrate these control functions, so they can focus more on the lamp output-stage design and speed up time-to-market. This article describes the design of a 25-W compact fluorescent lamp ballast using an IC that integrates many necessary control functions. Also discussed is the output-stage design, selection of programmable IC components, the schematic, ballast-measurement waveforms, and a comparison between predicted and measured results.
