Patent ID: 8064229
Filing Date: 2011-11-22
Classification: H02M,Y02B

Abstract:
1. A series resonant switching power supply control circuit comprising: a first input configured to receive a first sense signal that is representative of a secondary current through a secondary winding of a transformer of a series resonant switching power supply control system wherein the series resonant switching power supply control system has a resonant frequency; a second input that is configured to receive a trigger signal that is representative of a reversal of a primary voltage across a primary winding of the transformer; an output configured to form a switching drive signal that is used to operate a first switch that is coupled to the secondary winding; a first circuit configured to enable the first switch responsively to the secondary current increasing from a first value to a second value; and the first circuit configured to disable the first switch responsively to the secondary current decreasing from the second value to the first value for operating frequencies of the switching power supply control system that are no greater than the resonant frequency, and to disable the first switch responsively to the trigger signal and not responsively to the secondary current decreasing from the second value for operating frequencies of the switching power supply control system that are greater than the resonant frequency.