| 摘要 |
PURPOSE:To make easy circuit integration, by applying a voltage to the junction point between the resistor in series connection and the diode, and performing constant current drive for the semiconductor communication path switch without being affected with the variation in the power supply voltage. CONSTITUTION:The currents flowing out from a pair of collectors of the multi- collector transistor TrQ21 are made equal by specifying with the base to emitter voltage of TrQ21. Further, the collector current values of pair TrQ22a and TrQ22b are made equal by specifying with the base to emitter voltage of TrQ 22a and 22b. Further, the respective the emitter voltage of TrQ21 and pair TrQ22a, 22b is taken as the voltage across the reference voltage diode D21 or D22 subtracted from the current flowing to the diode D21 is kept constant by TrQ22b, and the current kept constant by TrQ21 is flowed in the diode D22. Further, the voltage across the diode D21 and 22, can be kept constant independently of the power supply voltage variation. |
