US 12,395,085 B2
Switching power-supply unit
Hiroyuki Takatsuji, Nagaokakyo (JP); and Tatsuya Hosotani, Nagaokakyo (JP)
Assigned to Murata Manufacturing Co., Ltd., Kyoto-fu (JP)
Filed by Murata Manufacturing Co., Ltd., Kyoto-fu (JP)
Filed on Mar. 22, 2023, as Appl. No. 18/188,289.
Claims priority of application No. 2022-049348 (JP), filed on Mar. 25, 2022; and application No. 2023-009496 (JP), filed on Jan. 25, 2023.
Prior Publication US 2023/0308023 A1, Sep. 28, 2023
Int. Cl. H02M 3/335 (2006.01); H02M 1/00 (2006.01); H02M 1/12 (2006.01)
CPC H02M 3/33523 (2013.01) [H02M 1/0064 (2021.05); H02M 1/123 (2021.05)] 20 Claims
OG exemplary drawing
 
1. A switching power-supply unit comprising:
a power conversion circuit that includes a first input capacitor, at least one power-conversion switching device for power conversion, and a first output capacitor, and the power conversion circuit is configured to convert, for output to a load, power supplied from a first direct-current power supply;
a control circuit that includes a second input capacitor and at least one switching drive circuit, and control circuit is configured to generate a drive signal for the at least one power-conversion switching device by using power supplied from a second direct-current power supply, the control circuit having a direct electrical connection to the power conversion circuit;
a class-Y capacitor that is connected to the power conversion circuit on a side of the first direct-current power supply of the power conversion circuit, and that is connected to a ground potential; and
a common-mode choke coil that is connected to the control circuit on a side of the second direct-current power supply of the control circuit,
wherein a noise balancing circuit is configured of a closed circuit including the power conversion circuit, the control circuit, the class-Y capacitor, and the common-mode choke coil, and the noise balancing circuit is configured to confine common-mode currents to cancel out each other, the common-mode currents being switching noise generated in a plurality of parts of the closed circuit due to a switching operation of the at least one power-conversion switching device.