| 摘要 |
PURPOSE:To prevent the burnout and damage of a stepping motor caused by the reckless driving of a central processing unit by monitoring the pulse width of the driving pulse of the stepping motor and generating an prohibition signal when the pulse width becomes a predetermined value or more and prohibiting the supply of the driving pulse to the stepping motor on the basis of the prohibition signal. CONSTITUTION:The four-phase pulse signals generated from a central processing unit 1 are supplied to a pulse width monitoring circuit 2 to monitor pulse width and prohibits the output of a pulse of a predetermined width or more to a stepping motor 4. The rising of the output of an OR gate 21 is triggered to start the operation of a timer 22. The output from the timer 22 is supplied to a switching gate circuit 23 as a gate signal and the respective four-phase pulse signals are supplied to a transistor driving circuit 3 to control the circuit 3. When the timer time of the timer 22, that is, pulse width (pulse time) as a gate signal is determined to a predetermined time, the supply of a pulse having time width of a predetermined time or more to the transistor driving circuit 3 is prohibited. |
