| 摘要 |
A permanent magnet d.c. motor control circuit includes an output amplifier B having the motor M as its load. A driver amplifier A has its output connected to the input of the output amplifier A by a resistor chain R15, R16, R17. A feedback signal take-off point X on this chain provides a feedback signal which is combined with a reference voltage signal from a reference signal generator R1, ZD1, R2, R3, R4, to provide a bias signal to the input of a switching amplifier T2, T3 which has a transient positive feed-back path. The switching amplifier controls the output amplifier so that the mark-to-space ratio of the output thereof is determined by the reference signal independently of any supply voltage variations. |
