| 摘要 |
PURPOSE: To surely start. a motor even if a power supply voltage is low by providing a switching means for short-circuiting a current detecting means in a driving device provided with an H-bridge type driving circuit driving the motor and the driving current detecting means for the motor. CONSTITUTION: The motor M is connected to transistors Q1, Q2, Q3 and Q4 constituting the H-bridge type driving circuit. A detecting resistance Rs for detecting a driving current is connected to the H-bridge type driving circuit in series. Moreover, a transistor Q5 used for short-circuiting the detecting resistance Rs is connected thereto in parallel. When the detection of the driving current is unnecessary, the dropping of the voltage of the current detecting means is switched by the control of the transistor Q5 of the switching means. The dropping of the voltage of the current detecting means is controlled, so that the driving current can not be detected at this time, but the torque of the motor is increased to reduce a failure in starting. |
