Switching power supply device
AssigneeYazaki Corporation
InventorsShota Yoshimitsu, Satoshi Ito
Life of this patent
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Abstract
In a switching power supply device, a snubber circuit includes a snubber capacitor, a FET, and a snubber inductor. The snubber capacitor stores therein surge power due to a reverse recovery time of FETs. The FET discharges the surge power stored in the snubber capacitor. The snubber inductor is provided in a stage following the FET. The controller controls an actual on-duty at which the FET of the snubber circuit is turned on based on the surge power. The controller can set an on-duty lower limit indicating the lower limit of the actual on-duty. The on-duty lower limit is smaller than the actual on-duty set for the FET in a continuous current mode in which an electric current flowing through the snubber inductor continuously flows and larger than 0.
Claims6
A switching power supply device comprising:
- a switching circuit configured to convert DC power supplied from a DC power supply into AC power;
- a rectifier circuit including a plurality of rectifier elements configured to rectify the AC power resulting from conversion by the switching circuit;
- a snubber circuit including a power storage element configured to store therein surge power due to a reverse recovery time of the rectifier elements, a switching element configured to discharge the surge power stored in the power storage element, and an inductor provided in a stage following the switching element;
- and
- a controller configured to control an on-duty at which the switching element is turned on based on the surge power, wherein
- the controller is capable of setting an on-duty lower limit indicating a lower limit of the on-duty, and
- the on-duty lower limit is smaller than the on-duty set for the switching element in a continuous current mode in which an electric current flowing through the inductor continuously flows and larger than 0, and wherein
- the on-duty lower limit is equal to or larger than the on-duty of the switching element capable of outputting a snubber current minimum value serving as a minimum value of an electric current output from the snubber circuit.
Dependencies are inferred from the claim text.