| 摘要 |
PURPOSE:To cause the actions of a CMI CODEC, etc., including an ECL(Emitter Coupled Logic) input circuit to be operated of high-speed and to miniaturize a chip by realizing the ECL input circuit of one stage constitution to simplify a circuit and to highly speed up the action. CONSTITUTION:The ECL input circuit of the CMI CODEC is composed of a current switching circuit composed of transistors T1 and T2 to compare decide the level of an input signal VE according to a prescribed referring potential VR, a level shifting circuit composed of the transistor T1 to receive the input signal VE, of a diode D1 and of a constant current source I S1, and a P channel MOSFETQP1 and an N channel MOSFETQN1 to be provided between a power source voltage VDD and a power source voltage VSS in a serial form and to receive output signals VP1 and VN1 of the current switching circuit and level shifting circuit to their gates, respectively. The signal VP1 is designed so that its central value can be made into the threshold voltage of the FETQP1. The signal VN1 is generated so that its central value is made into the value in which the threshold voltage of the QN1 of the FET is added to the power source voltage VSS. |
