JPS5641788A - Controlling circuit for transistor motor - Google Patents

Abstract

PURPOSE:To prevent the generation of the torque ripples in the transistor motor by feeding back the voltage having a value corresponding to an armature current to an operation amplifier which is inserted between a Hall element and a transistor for driving armature windings. CONSTITUTION:When the potential at the output terminal c of a Hall element 6 is larger than the potential at the output terminal d thereof, the sine wave output from the Hall element is amplified at a constant gain determined by resistors 24, 25, and 28 in an operation amplifier 34, and drives a transistor 8. When the potential at the point d is larger than the potential at the point c, the transistor 8 is cut off. On the other hand, the voltage whose value corresponds to the current of armature windings 12 and 14 is fed back to the reverse phase input terminal of the operation amplifier 34 from the emitter of the transistor 8 via the resistors 24 and 25. In this constitution, the collector current, i.e., the armature current flows at a constant gain, without regard to the characteristics of the transistor, and the sine wave current corresponding to the output of the Hall element is generated