| 摘要 |
A duty ratio control device of a stepping motor in a bill depositing and drawing machine is provided to keep the rotational speed of the stepping motor constant by detecting current supplied to the stepping motor and controlling a duty ratio of driving pulse according to the detected current. A duty ratio control device for controlling a duty ratio of a stepping motor(26) driving a roller installed in a bill depositing and drawing machine is composed of a stepping motor driving unit(22) supplying driving voltage having a predetermined duty ratio for driving the stepping motor, according to a driving control signal of a control unit; a current sensing and converting unit(24) detecting a current value of the stepping motor and converting the current value into the detected driving voltage actually applied to the stepping motor; a duty ratio conversion DB(Database,28) defining the duty ratio corresponding to the detected driving voltage; and the control unit comparing the detected driving voltage and the driving voltage supplied from the stepping motor driving unit, controlling the duty ratio according to the comparison result, and supplying the controlled duty ratio to the stepping motor driving unit as a driving control signal. |
