| 摘要 |
PURPOSE:To reduce the dispersion of a reference voltage for judging the abnormality of a motor to the very small level. CONSTITUTION:This circuit has Hall elements HE1-HE3 and Hall amplifiers HA1-HA3 for amplifying the output signals of the Hall elements. A control part 1 which controls exciting currents to be supplied to coils U, V and W based on the output signals of the sensors HE1-HE3 is connected to the output sides of the amplifiers HA1-HA3. Adriver part 2 and the output side of a current detecting part are connected to the control part 1. One end of a resistor R1 through which the exciting current to be supplied to the coils U, V and W flows is connected to the current detecting part. In the current detecting part, the feeding of the exciting currents is stopped when the motor is abnormal based on the converted voltage V in the resistor R1 and a reference voltage Vs, and the motor is stopped. In the current detecting part, a resistor R4' which is connected in series between the power supply voltage Vcc and the ground and a node N between a diode D and the resistor R4 are connected on the input side of the reference voltage Vs. |
