A power converter provides constant load power while achieving a high
power factor in a single stage configuration with reduced component count
and ratings. The power converter takes a rectified line input to a
switching half-bridge that supplies current to a load. A series
combination of shunt switch and capacitor is connected across the load to
store energy from the input and supply energy to the load. The switches
are operated with conduction angles that achieve constant power supplied
to the load while drawing a sinusoidal current in phase with the input
voltage to achieve high power factor. The circuit provides a simplified
configuration over prior power converters that may be used with a
resonant load as part of an electronic ballast or an AC-to-DC converter.
The power converter configuration and operation also achieves a low total
harmonic distortion on the input line power.