| 摘要 |
PURPOSE:To reduce the torque ripple of a motor by controlling a Hall element drive circuit so that the voltage between the terminals of a Hall element power source becomes proportional to the input control voltage and in response to the comparison deviation between the partial voltage between the terminals and the reference voltage. CONSTITUTION:A control voltage vi from a motor speed controller, not show, is inputted to a terminal 10, and a current is flowed through a differential amplifier 11 and a transistor (Tr) Q1 to a resistor R1. The current i flows also to a Tr Q2 forming a current mirror circuit, the voltage of the resistor R2 of a drive stage controller having a Tr Q2, a diode D2, a resistor R2(=R1), a diode D3, and a resistor R3 becomes vi, and the output of the Hall element 4 becomes proportional to the vi. On the other hand, the output of a voltage divider having resistors R3, R4 including equal resistance value is inputted to a differential amplifier 13 representative of the neutral voltage v0 of the output of the Hall elements 4, is compared by the reference voltage VB/2, thereby fixing the voltage v0 to 1/2 of the power source voltage VB. |
