Patent ID: 7633780
Filing Date: 2009-12-15
Classification: H02M

Abstract:
1. A synchronous rectification type switching power supply apparatus, comprising: a transformer to receive input voltage on a primary side; a switching element that is to be turned on or off for rectifying current of a secondary coil of the transformer; a control circuit to drive the switching element, the control circuit including a first timing detection circuit to detect first timing at which forward current flows through a body diode of the switching element, and a second timing detection circuit to detect second timing with counter electromotive voltage that is generated at an instant when the body diode is turned off, wherein the control unit is to generate an on/off control signal for the switching element to turn on the switching element at the first timing, to turn off the switching element before the second timing and to bring off-timing of the switching element close to the second timing.