| 摘要 |
PURPOSE:To abruptly stop rotation of a brushless motor when supply of a power source is stopped. CONSTITUTION:A power supply stop sensor 22 for sensing the fact that supply of power source is stopped according to OFF of a main switch SW1, is provided. A controller 20 turns ON all transistors Q1-Q3 according to the output of the sensor 22, and turns OFF all transistors Q4-Q6. Thus, when a rotor 2 is rotated by an inertial force, it is braked by using a counterelectromotive force induced in a coil 9. The sensor 22 senses stop of the supply of power source from a step-down output. Thus, even if the power supply is stopped, it is braked in a state that the other circuit of a driving circuit is active due to a delay in the voltage drop of the driving power source. |
