Method for reducing mains harmonics and switching losses in discontinuous-mode, switching power converters

摘要

A method for reducing harmonic distortions and switching losses in a power factor correction circuit of a quasi-resonant voltage converter, wherein using data derived from the sensing a voltage impressed on the switching device in the power converter, a multitude of event times can be calculated that will align the timings of the drive circuitry of the power converter to those of the natural resonance transitions of reactive elements of the converter. An over-sampling of the voltage impressed on the switching device voltage allows accurate sensing of a "zero-current" cross-over condition in an inductance of the converter.