Patent attributes
An apparatus comprises a controller operative to: i) monitor a resonant voltage associated with a primary winding magnetically coupled to a secondary winding; ii) control a flow of current through the primary winding to produce an output voltage at the secondary winding; and iii) control magnetization of the primary winding with respect to a detected a zero crossing event associated with the monitored resonant voltage. The controller further controls a duration of activating a switch coupled to an auxiliary winding (which is magnetically coupled to the primary winding) based on a magnitude of the monitored resonant voltage and/or a magnitude of an input voltage supplied to the primary winding. The controller operates in different modes of magnetizing the primary winding such as at peaks or valleys of the monitored resonant voltage depending on a magnitude of the input voltage.
