| 摘要 |
PURPOSE:To prevent a variation in torque of an n-phase stepping motor when an n-phase excitation and an (n-1)-phase excitation are alternately repeated. CONSTITUTION:When a switching transistor 2 is turned ON according to a phase excitation signal Vp from a signal generator 8, a winding current IL flows to a motor winding 1. The current IL is detected as a detected voltage V1 by a current detecting resistor 4, and compared with a reference voltage V0 from a reference voltage generator 7 by a voltage comparator 5. The current IL is controlled to a value corresponding to the voltage V0 by a pulse width controller 6. The voltage V0 is switched in response to the number of exciting phases according to a voltage select signal VS from the generator 8, thereby so varying the current IL as to always becomes a predetermined torque. |
