Patent attributes
This switching power supply device having a plurality of power supply circuits to be connected to a multi-phase power supply, is provided with: a first substrate on which an electric component constituting a filter circuit is mounted, the output end of the filter circuit being provided on one end side in a first direction; a second substrate on which a power semiconductor constituting a circuit provided at a stage later than the filter circuit is mounted, the input end of the circuit provided at the stage later than the filter circuit being provided on one end side in a second direction that intersects with the first direction; and a third substrate which is disposed between the first substrate and the second substrate, and on which a wiring pattern for electrically connecting the output end to the input end is formed.