Performance Comparison between Nested Differentiating Feedback Loops and The Classical Three Stage Operational Amplifier Architectures; a SPICE - based simulation Approach

摘要

Since 1970, the three stage operational amplifier with dominant pole compensation has become the standard basis in amplifier's architectures. However, during the 80's and following years the nested differentiating feedback loops (NDFL) concept was introduced by Edward M. Cherry, as an attempt to improve the classic power amp performance, mainly distortion caused by class B output stages. The proposal of this work lies on the first part of a comparison between both topologies' performance in a SPICE based simulator. Most important analysed parameters are open-loop gain, distortion, transient response and of course stability. In addition, modern semi-conductor devices and typical inner stages are used to make the comparison circuits, based on small signal devices such as discrete operational amplifiers.