| 摘要 |
PURPOSE: To reduce disturbance against electric supply of a system board by biasing an NPN bipolar transistor to turn on this transistor. CONSTITUTION: A control logic circuit L1 rapidly discharges electric charge from a decoupling capacitor C4 and a load RL rapidly discharges electric charge from a load capacitance CL when system electric supply is eliminated. A blocking diode CR1 tries to prevent a capacitor C2 from discharging to the load RL. In that case, power-supply voltage on an emitter side of an NPN bipolar transistor Q2 becomes lower than the voltage of the capacitor C2, a base emitter junction of the transistor Q2 is forwardly biased and the transistor Q2 is turned on. Thereby, controlled electric power can be supplied the load RL through an electric power control circuit and the disturbance against electric supply of the system board can be decreased. |
