| 摘要 |
PURPOSE:To eliminate noise to be generated at a power source line by simultaneously turning two transistors of a ground side for forming an H bridge to ON at the time of stopping a motor. CONSTITUTION:The output of a driving circuit 8 at the time of stopping a motor is varied from a low level to an M level at this time, and two Q3, Q4 of four transistors Q1 to Q4 for constituting an H bridge are turned ON by the operation of a changeover switch circuit 6 composed of diodes D5, D6, D7. If the circuit 8 is not formed at the time of stopping the motor, counterelectromotive force of a motor coil 9 regenerated in a motor driving power source Vm 11 through the diode D1 or D2 at the moment of stopping the motor is discharged through a loop of the transistor Q3 and the diode D4 or the transistor Q4 and the diode D3, and hence influence to the power source 11 can be reduced. |
