To suppress a peak value of a recovery surge voltage from becoming large.
A power supply device includes: a battery 29; a film capacitor 21; transistors 23, 25; gate resistors 24, 26; a flywheel diode 22; a current sensor 27; and a control unit 30. When a load current detected by the current sensor 27 is equal to or lower than a prescribed value, the control unit 30 outputs an on-signal to one of transistors 23, 25 (for example, only the transistor 23), and when the load current is larger than the prescribed value, the control unit outputs on-signals to both the transistors 23, 25. By this arrangement, the peak value of the recovery surge voltage can be suppressed from becoming large without using a large gate resistor, and a loss caused by the gate resistor can be suppressed.
SAKAKIBARA HIROYUKI
TORII KAORU
TOYOTA MOTOR CORP