| 摘要 |
PURPOSE:To stabilize the operation of a differential amplifier by providing the 1st and 2nd ECL to an emitter coupling circuit so as to avoid the saturation of an input transistor (TR) even when the input becomes 0V. CONSTITUTION:A conventional emitter coupling circuit ECL consists of TRs Q1, Q2 and outputs O, O' depending on the level of an input IN. A resistor RI is connected between the input IN of the ECL circuit and the base of the TR Q1 and TRs Q3, Q4 constituting the 2nd ECL are connected between one terminal of the resistor RI and an emitter of the TRs Q1, Q2 connected to the constant current source I. The constant current source I is connected to the base of the TR Q3, the base of the TR Q2 is connected to the base of the TR Q4 and the constant current source I1 is connected to emitters of the TRs Q3, Q4. Then the base potential of the TR Q1 is brought into a range not saturated when the input is 0V by using the resistor R1 and the constant current source I1 so as to stabilize the operation of the differential amplifier. |
