| 摘要 |
PURPOSE:To increase the speed of solenoid response and reduce the power supply capacity, by periodically cutting power supply to a solenoid and utilizing the residual current in the solenoid produced by its self-induction. CONSTITUTION:Solenoid L is connected to power supply VCC via a quasi-Darlington circuit consisting of transistors T1, T2. The current in solenoid L is detected by resistor R14 and it is compared (CMP) with the reference value. Depending upon the magnitude of the solenoid current, transistor T3 is turned on or off and also switching circuit SW is turned on or off. When the power supply is cut off, the residual current produced by the self-induction of solenoid L flows in solenoid L and passes through L-R14-T5-D via transistor T5. This current gradually diminishes and turns T3 on. Then, T1, T2 are turned on again and power supply is constant, which eliminates protective resistance and increases the speed of response. At the same time, power consumption is reduced and the power supply capacity is also reduced. |
