High power factor correction circuit using valley charge-pumping for low cost electronic ballasts

A new cost-effective power factor correction (PFC) circuit, the improved valley fill (IVF) circuit combined with charge pumping capacitors (CPCs), used as an electronic ballast for fluorescent lamps is proposed. The IVF can adjust the valley voltage higher than half of the peak line voltage. The CPCs draw current from the input line to make up the current waveform during the valley interval. The measured power factor and total harmonic distortion for a prototype electronic ballast are 0.996 and 5.5%, respectively.