| 摘要 |
PURPOSE:To minimize a bad effect due to temperature change in a speed control loop of a motor by not giving an offset to a differential amplifier and by giving an offset to a feedback amplifier. CONSTITUTION:No offset is given to a differential amplifier used as a comparator 4 comparing a revolution speed signal V1 of a motor 1 and a standard signal E2. A feedback amplifier 5 is composed of a differential amplifier formed by transistors Q1, Q2 with emitter resistance R1, R2; of transistors Q3-Q5, with emitter resistance R3, R4, connected in current mirror as load for the differential amplifier; and of transistors Q6, Q7 for motor driving. With proper ratios among emitter resistance R1-R4, it can supply the motor 1 with a rated burden current at the time of zero base potential difference of the differential amplifier. |
