This application relates to power factor corrected (pfc) ac-dc power converters. The usual way of controlling power factor in an ac-dc power converter uses a boost converter input stage, boosting all of the input current to a high voltage storage capacitor. Then, all of the output current is taken from the high voltage storage capacitor through a buck converter output stage to the output. A transformer may be used to provide dielectric isolation and/or change the output voltage level.
Prior art pfc circuits are sluggish, difficult to control and inefficient.