Patent ID: 9001538
Filing Date: 2015-04-07
Classification: H02M,Y02B

Abstract:
1. A switching power supply apparatus comprising: a transformer including a primary winding and a secondary winding; a switching unit that repeatedly inverts a voltage applied to the primary winding; a conduction path that supplies a voltage excited in the secondary winding due to operation of the switching unit to a load that is connected between a high-potential side and a ground side of the secondary winding; and a first rectifier element that has a rectification direction extending from a high-potential side toward a ground side of the load and that is provided along the conduction path; wherein a second rectifier element and a first capacitor, which are connected in series with each other, are connected in parallel with the secondary winding; the second rectifier element has a rectification direction extending from the high-potential side toward the ground side; a resistance and/or an inductive impedance is connected in parallel with the second rectifier element; a charge accumulated in the first capacitor is discharged in a period after the first rectifier element transitions to a non-conductive state from a conductive state; a portion of the charge discharged from the first capacitor is consumed by the resistance and/or the inductive impedance in order to suppress a surge voltage; and another portion of the charge discharged from the first capacitor is once again accumulated in the first capacitor in a reverse direction.