| 摘要 |
<p>PURPOSE:To obtain a differential amplifier circuit with a small offset voltage by connecting an FET with the pinch-off characteristic similar to that of a signal input FET as a load of the FET receiving said signal. CONSTITUTION:Suppose that a pinch-off current Idss1 of an FET 1 is larger than a pinch-off current Idss2 of an FET 2, a gate-source voltage Vgs1 of the FET 1 has a relation of Vgs1>Vgs2 with respect to said voltage Vgs2 of the FET 2 and an offset voltage is generated. Since the pinch-off current of an FET 3 is larger than the pinch-off current of an FET 4, a current flowing to an npn transistor(TR) 5 is increased. Then a current flowing to an npn TR 7 is decreased and the current of the FETs 1, 2 is varied to attain Vgs1=Vgs2. Since the current flowing to the FETs 3, 4 is distributed from a constant current circuit 9, the offset voltage is reduced more than the compensation effect by the FETs 1, 3 and the FETs 2, 4.</p> |
