Patent ID: 9742342
Date: 2017-08-22
CPC Classifications: H02K,H02P

Claim:
1. A motor driving apparatus adapted for driving a motor of a power tool, said motor driving apparatus comprising: a first switch having a first terminal that is adapted for receiving an external voltage, and a second terminal, said first switch being operable between an ON state and an OFF state; a driving circuit coupled to said first terminal of said first switch, and adapted to be coupled to the motor, said driving circuit being powered by the external voltage, and being operable to drive the motor to rotate in first and second directions; a control circuit coupled to said second terminal of said first switch and said driving circuit, and configured to control said driving circuit based at least on an operating state of said first switch; and a power circuit coupled across said first switch and to said control circuit, receiving the external voltage, and selectively outputting, based on the operating state of said first switch, an internal voltage associated with the external voltage to power said control circuit, the internal voltage being outputted when said first switch operates in the ON state and for a predetermined time period counting from every instant of said first switch transitioning from the ON state to the OFF state; wherein said control circuit is powered by the internal voltage to control said driving circuit to drive the motor to rotate in the first direction when said first switch operates in the ON state, and to rotate in the second direction for the predetermined time period each time said first switch transitions from the ON state to the OFF state; wherein said power circuit includes a second switch coupled between said first terminal of said first switch and said control circuit, and receiving the external voltage; and a control unit coupled to said second terminal of said first switch and said second switch, and controlling, based on the operating state of said first switch, operation of said second switch between an ON state and an OFF state such that said second switch operates in the ON state to permit output of the external voltage thereat to serve as the internal voltage for the duration that said first switch operates in the ON state and until the end of the predetermined time period after said first switch transitions from the ON state to the OFF state.