| 摘要 |
PURPOSE:To reduce the controlling error and to protect a circuit by detecting the amount of a drive current of a motor, comparing it with a control signal to control the drive current, and comparing it with a reference signal to selectively interrupt the control signal. CONSTITUTION:Signals of Hall elements 1-3 are respectively converted via voltage/current converters 7-9, applied through transistors Q5-Q10 to output circuits 11-13 to drive the windings of a motor, the currents are detected by a resistor RX, the voltage VX and reference means VREF1 are compared, a transistor Q21 is controlled by the comparison with a control signal SC in case of VX< VREF2, Q6, Q8, Q10 are controlled to control the drive current. In case of VX> VREF2, Q21 is turned OFF, Q6, Q8, Q10 are turned OFF to interrupt the drive current. Accordingly, the amount of the drive current is detected to control or interrupt it, thereby reducing the controlling error and to protect the circuit. |
