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Step motor driving circuit

  • US 4,463,301 A
  • Filed: 07/09/1982
  • Issued: 07/31/1984
  • Est. Priority Date: 07/10/1981
  • Status: Expired due to Fees
First Claim
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1. A step motor driving circuit for a step motor comprising:

  • (a) A-phase and B-phase exciting windings, said A-phase and B-phase windings being independent of each other;

    (b) first current selection means for selectively applying currents having a first current value, a second current value or zero value to said A-phase windings, said first and second exciting currents being of a predetermined ratio, said first being larger than said second, said first current selection means varying said currents between said values with a gradually changing waveform;

    (c) second current selection means for selectively applying currents having said first current value, said second current value or zero value to said B-phase windings, said second current selection means varying said currents between said values with a gradually changing waveform; and

    (d) control means for applying control signals to said first and second current selection means in a four state sequence of four successive control signal groups to cause the latter to excite said A-phase and B-phase windings in the following sequence of states;

    excitation of one of said phase windings with a current of said first current value and the other of said phase windings with a current of zero value;

    excitation of said one winding with a current of said first current value and the other winding with a current of said second current value;

    excitation of both phase windings with currents of said first current value;

    excitation of said one winding with a current of said second current value and excitation of said other winding with a current of said first current value, whereby each successive four state excitation constitutes one step of said step motor.

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