| 摘要 |
PURPOSE:To prevent loud noise during stepping operation, by controlling current through a reference signal which increases gradually when rising and attenuates gradually when falling. CONSTITUTION:Voltage induced across a resistor 25 for detecting current flowing through an exciting coil A or C is compared with a reference voltage V'ref produced from a reference voltage generator 41. ON/OFF operation of a transistor 34 for feeding exciting current I11 is controlled corresponding to comparison result. The reference voltage generator 41 generates the reference voltage V'ref which increases gradually to a high level when exciting timing rises and attenuates gradually to a low level when the exciting timing falls. |
