Patent ID: 11909310
Assignee: MURATA MANUFACTURING CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 20:
21. A switching power supply device comprising:
a power conversion circuit that is provided at a multilayer printed board and includes a plurality of switching circuits and a controller configured to control the plurality of switching circuits;
a plurality of windings that are at the multilayer printed board, each of the plurality of windings configuring an inductor having a first end and a second end; and
a magnetic sheet that is provided on one or both of an upper face of the multilayer printed board and a lower face of the multilayer printed board, the magnetic sheet being made of a soft magnetic body configuring a magnetic layer,
wherein
the plurality of windings have conductor patterns at the multilayer printed board,
the plurality of windings are arranged along a plane of the multilayer printed board,
the first ends of the plurality of windings are connected to the plurality of switching circuits, and the second ends of the plurality of windings are connected to a common output,
the controller is configured to control the plurality of switching circuits to periodically vary a position and a time at which magnetic flux generated by current flowing to the plurality of windings reaches maximum magnetic flux density, and
the magnetic sheet is made of soft ferrite and an Ni—Zn—Cu sintered ferrite material with a maximum relative permeability at a frequency of 10 MHz or more.