DC MOTOR AND PUMP

PROBLEM TO BE SOLVED: To eliminate back electromotive force absorption to a DC power supply by a back electromotive force occurring in winding of a phase stopping conduction and to prevent a load applied on a circuit element. SOLUTION: A switching control means 5 performs continuous OFF control on high-side switching elements 311, 321 and 331 or low-side switching elements 312, 322 and 332 performing continuous ON control at the time of switching a combination of windings 21, 22 and 23 of conduction phases U, V and W, and performs continuous ON control on the low-side switching elements 312, 322 and 332 or the high-side switching elements 311, 321 and 331 performing PWM control. It performs PWM control on the high-side switching elements 311, 321 and 331 or the low-side switching elements 312, 322 and 332 connected to windings 21, 22 and 23 which newly become the conduction phases U, V and W. COPYRIGHT: (C)2010,JPO&INPIT