US 12,136,882 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. 18/188,227.
Claims priority of application No. 2022-049349 (JP), filed on Mar. 25, 2022; and application No. 2023-009495 (JP), filed on Jan. 25, 2023.
Prior Publication US 2023/0308022 A1, Sep. 28, 2023
Int. Cl. H02M 1/44 (2007.01); H02M 3/158 (2006.01); H02M 3/335 (2006.01)
CPC H02M 3/33523 (2013.01) [H02M 1/44 (2013.01); H02M 3/158 (2013.01)] 16 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 configured for power conversion, and a first output capacitor, and the power conversion circuit is configured to convert power supplied from a first direct-current power supply; for output to a load;
a control circuit that includes a second input capacitor and at least one switching drive circuit, the 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, and the control circuit has a direct electrical connection to the power conversion circuit;
a control-circuit-side 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;
a first half-bridge 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
a second half-bridge capacitor that is connected to the control circuit on the side of the second direct-current power supply of the control circuit,
wherein
a midway point of the first half-bridge capacitor is electrically connected to a midway point of the second half-bridge capacitor, and
a noise balancing circuit is configured of a closed circuit including the power conversion circuit, the control circuit, the first half-bridge capacitor, the second half-bridge capacitor, and the control-circuit-side 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.