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MOTOR DRIVING DEVICE

  • US 20090058336A1
  • Filed: 08/20/2008
  • Published: 03/05/2009
  • Est. Priority Date: 08/29/2007
  • Status: Active Grant
First Claim
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1. A motor driving device for driving a three-phase brushless motor without using a hall sensor, comprising:

  • a filter circuit which receives coil terminal voltages of each phase of the three phase coils of said three-phase brushless motor and a center tap voltage of said three-phase coil so as to remove a voltage component resulting from a current ripple included therein; and

    a voltage comparing portion including a comparator which compares a coil terminal voltage of each phase after filtering the coil terminal voltage of said each phase with a center tap voltage after filtering of said center tap voltage, whereinsaid comparator sets a comparison voltage with said coil terminal voltage of each phase after filtering based on an offset signal to a value supplied with a higher offset voltage than said ripple voltage after filtering.

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