High frequency electronic ballast provides line frequency lamp current

Most electronic ballasts for fluorescent lamps provide a sinusoidal lamp cu rrent at the switching frequency. The high-frequency current flowing throug h the lamp can generate significant radiated noise, which is unacceptable i n noise-sensitive applications, such as fluorescent lights in airplanes. Us ing shielded enclosures for the lamps may solve the problem, but it is expe nsive. A discontinuous conduction mode (DCM) electronic ballast topology is presented which drives the lamp with line frequency current, just like a m agnetic ballast. However, compared to a magnetic ballast, its weight is sub stantially reduced due to operation at 40 kHz switching frequency. The topo logy also ensures unity power factor at the input and stable lamp operation at the output.