| 摘要 |
PURPOSE:To control revolution of a DC motor with a small power loss by keeping the voltage, which is impressed on a semiconductor element of the power amplification section for controlling impressed voltage on a load, at almost constant value regardless of load control signals. CONSTITUTION:The voltage Vm impressed on a DC motor M, which is a load, is supplied from the power amplification section 2 controlled by the speed control signal Ein. When rpm of the motor M is fixed, the voltage Vm is fixed at a low value. Consequently, for reducing the power to be consumed by the transistors Q1, Q2 of the amplification section 2, the voltage E1', E2' of the power sources A', B' of the amplification section 2 is reduced. The power sources A', B' are to be of variable-type and the voltage control thereof is performed according to the detection value of the difference between the voltage E1', E2' and the voltage Vm or to the value of the speed control signal Ein. |
