| 摘要 |
PURPOSE:To completely amplify a difference voltage between an inverting input and a noninverting input by selecting a ratio of a conductance coefficient of 1st and 2nd amplifier transistor(TR) to that of a 2nd load and a current source TR of a differential amplifier stage to a prescribed value, respectively. CONSTITUTION:When a Vc is turned off, an N-channel transistor(NT) 42 is turned off and a PT 43 is also turned off by an inverter 53 and a current is supplied to each conduction path. The PT 43 has a lower threshold voltage than the NT 44 and has a lower conductance(CD) coefficient, then a bias voltage VB is slighly higher than the threshold voltage of the NT 44. When the potential of an inverting input V1 and a noninverting input VN1 becomes higher than the threshold voltage of the NTs 46, 47, since the current flowing to the NT 45 is constant, the ratio of the conductance coefficients of the PTs 49, 51 is takes as a double of that of the NTs 45 and 50 and the TRs 49, 50 and 45, 50 are arranged closely to make the threshold voltage equal, then only the difference voltage of the voltages V1 and VN1 is amplified.
|
