Patent ID: 9705414
Date: 2017-07-11
CPC Classifications: H02M

Claim:
1. A method of operating a switched-mode power supply, the method comprising: de-activating a first switch coupled to a primary winding of a transformer in the switched-mode power supply to create a voltage difference across the primary winding of the transformer, the transformer comprising a secondary winding that includes at least a first winding portion coupled in series with a second winding portion, wherein an inductor is coupled in series to the second winding portion of the secondary winding; activating a second switch to generate a current imbalance between the first winding portion and the second winding portion of the secondary winding, wherein a load path of the second switch is coupled to a common node, the common node being common to both the first winding portion and the second winding portion of the secondary winding, and wherein the current imbalance between the first winding portion and the second winding portion of the secondary winding comprises an excess current that flows through the second winding portion of the secondary winding without flowing through the first winding portion of the secondary winding; de-activating the second switch to reduce a voltage difference across the first winding portion of the secondary winding; and re-activating the first switch to initiate charging of the transformer in the switched-mode power supply after the de-activating the second switch.