| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a rotating state of a rotor and appropriately drive a stepper motor. <P>SOLUTION: A control circuit 52 controls a drive circuit 32 and intermittently applies drive pulses comprising comb tooth pulses to an exciting coil 114. A first peak hold circuit 413 holds a peak value of reflux current flowing in the exciting coil 114 after application of each comb tooth pulse over a drive pulse application period. A second peak hold circuit 414 holds a peak value of reflux current flowing in the exciting coil 114 after application of each comb tooth pulse. A comparator 415 compares outputs of the first and second peak hold circuits 413 and 414, and outputs the comparison result. The control circuit 52 determines that a rotor is not rotated normally when a predetermined recess is not generated in the peak value of the reflux current based on the output of the comparator 415, and applies correction pulses to the exciting coil 114 so as to appropriately drive a stepper motor. <P>COPYRIGHT: (C)2012,JPO&INPIT |
