Features of Increasing the Fast Response of Differential Operational Amplifiers on the Basis of a 'Folded' Cascode

摘要

New and prospective circuit techniques for increasing the fast response of operational amplifiers (Op-Amps) containing the so-called "folded" cascode in the structure of an intermediate stage (IC) are considered. It is shown that under the constraints on power consumption in the static mode, the classical solutions of the Op-Amp of this subclass can not provide increased values of the maximum slew rate (SR) due to the nonlinearity of the transfer characteristic of the FC. Comparison of the methods for excluding the limitations of the output current of the "folded" cascode is given. Perspective architecture of high-speed micro-power Op-Amps with a differentiating correction circuit is proposed, which enables to increase the SR by 1-2 orders, incl. when working in the low temperature range and under conditions of penetrating radiation.