| 摘要 |
To provide a stepping motor drive apparatus for driving a stepping motor, that is a driving object, with low noise and low vibration. The stepping motor drive apparatus is composed of: a reference signal generation unit for generating a reference signal that shows a limit value of a current to be supplied to a coil; a switching unit for supplying the current to the coil in an ON state and stopping the current supply to the coil in an OFF state; a coil current measurement unit for measuring the current supplied to the coil; a standard pulse generation unit for outputting a standard pulse at a fixed time interval; a timer unit for outputting a completion signal showing that a predetermined period of time shorter than the fixed time interval has elapsed since the standard pulse was outputted; and a pulse-width modulation control unit for setting the switching unit to the ON state at a point in time when the standard pulse is outputted, and setting the switching unit to the OFF state either at a point in time when the current measured by the coil current measurement unit exceeds the current limit value shown by the reference signal or at a point in time when the completion signal is outputted from the timer unit, whichever occurs first.
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