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MOTOR DRIVE CIRCUIT

  • US 20100181951A1
  • Filed: 01/21/2010
  • Published: 07/22/2010
  • Est. Priority Date: 01/22/2009
  • Status: Active Grant
First Claim
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1. A motor drive circuit comprising:

  • a drive voltage generation circuit generating a drive voltage corresponding to a target rotation speed of a motor;

    a first pulse generation circuit generating a first pulse signal having a first logic level and a second logic level, a duty ratio of the first logic level of the first pulse signal being configured to increase as the drive voltage increases;

    a second pulse generation circuit generating a second pulse signal having the first logic level and the second logic level, a duty ratio of the first logic level of the second pulse signal being different from the duty ratio of the first pulse signal; and

    a drive control circuit supplying a drive current to a coil of the motor at the duty ratio of the second pulse signal so as to start a rotation of the motor that is not rotating and supplying a drive current to the coil at the duty ratio of the first pulse signal after a predetermined time from the start of the rotation of the motor in response to a rotation signal corresponding to the rotation of the motor.

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