| 摘要 |
PURPOSE:To provide a drive circuit for a three-phase motor in which the power capacity of three-phase motor can be increased while suppressing noise without requiring any modification of the three-phase bridge circuit 1 or the switching control circuit. CONSTITUTION:The drive circuit for the three-phase motor comprises a three- phase bridge circuit 1 comprising a plurality of MOSFETs 6, 7, and a switching control circuit 2 for turning each MOSFET 6, 7 ON/OFF. The drive circuit drives the three-phase motor 5 based on an output from the three-phase bridge circuit 1 and a second three-phase bridge circuit 4, comprising a signal conversion circuit 3 and a plurality of MOSFETs 8, 9, is connected between the three- phase bridge circuit 1 and the three-phase motor 5. The signal conversion circuit 3 generates a switching signal for turning the MOSFETs 8, 9 in the second three-phase bridge circuit 4 ON/OFF in response to the output state of the three-phase bridge circuit 1, i.e., voltage High, voltage Low, or high impedance thus matching the output from the three-phase bridge circuit 1 with that from the second three-phase bridge circuit 4. |
