Yazaki Corporation

Teruki Yamauchi

Shunzou Ohshima

Shunzou Ohsima

To provide a power supply device which can reduce energy loss caused due to the forward-direction voltage of a flywheel diode. In a load circuit for subjecting an electronic switch Tprovided between a DC power supply VB and a motor Mto the PWM control to thereby drive the motor M, a MOSFET (T) is provided in parallel to the motor M. A parasitic diode Dp of the MOSFET (T) is provided in a manner that its forward direction is in opposite to the flowing direction of a load current ID. The MOSFET (T) is turned on during a part of a period during which the electronic switch Tis placed in an off state to thereby flow a circulation current flowing through the motor Minto the MOSFET (T). Thus, the energy loss can be remarkably reduced as compared with the case of using the flywheel diode.

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Kosai, Japan

Teruki Yamauchi