| 摘要 |
PURPOSE:To interrupt power supply to a driving circuit by providing a dead zone characteristic at a part of signal processing circuit in a rotor position detector and interrupting power supply to the driving circuit when the output signal from the position detector stays in the dead zone for a predetermined time or longer. CONSTITUTION:A two-phase unipolar driving circuit is shown on the drawing where output signals from a position detector 3 are fed to Q3, Q4, Q5 having dead zones and subjected to signal processing. Since the dead zone can be set arbitrarily based on VL, Vu, it is set as uniform as possible with the setting position of the position detector 3 as a center. Output Vo from a transistor S3 is passed through an integrating circuit comprising a resistor R1 and a capacitor C1 and connected to + input terminal of a comparator Q5. - input terminal of the Q5 is inputted with a reference voltage Vr divided by a resistor. Output of the Q5 is inputted to the base of an NPN switching transistor S4 having collector connected with the base of a control transistor S5 arranged in series on + side. A resistor R2 is connected with the collector of the S4 and a power supply +Vcc. |
