High frequency electronic ballast provides line frequency lamp current

Most electronic ballasts for fluorescent lamps provide a sinusoidal lamp current at the switching frequency. The high-frequency current flowing through the lamp can generate significant radiated noise, which is unacceptable in noise-sensitive applications, such as fluorescent lights in airplanes. A discontinuous conduction mode (DCM) electronic ballast topology is presented which drives the lamp with line frequency current, just like a magnetic ballast. However, compared to a magnetic ballast, its weight is substantially reduced due to operation at 40 kHz switching frequency. The topology also ensures unity power factor at the input and stable lamp operation at the output.