复合运放在有源网络频率补偿中的应用

Applications of Composite Operational Amplifiers to Frequency Compensation of Active Networks

介绍了一种由运放实现的改善有源网络频率性能的通用方法。这种方法采用由Ｎ个运放构成的复合运放（ＣＮＯＡ）来取代有源网络中的每一个运放获得的。讨论了复合运放在ＲＣ正弦波振荡器工作频率扩展中的应用，分析了运放有限增益带宽积（ＧＢ）对ＲＣ正弦波振荡器工作频率的影响。分析结果表明，对于一定的ＧＢ，振荡器频率小于理论值，其误差随频率增大而增大。采用复合运放可降低由ＧＢ引起的误差，改善了振荡器频率性能。

A general approach is presented for extending the useful operating frequencies and improving the performance of active networks realized by use operational amplifiers (OA'S). This is achieved from replacing each operational amplifier in the active network by a composite operational amplifier constructed using N operational amplifiers (CNOA). This paper describes the use of composite operational amplifiers to extend the operating frequency range of an OAbased RC-sinusoidal oscillator. The effect of the finite gain-bandwidth product(GB) of OA on operating frequency of RC-sinusoidal oscillator is analyzed. Analytical results show that for a certain GB the frequency of oscillation is less than the theoretical value and that the error increases with frequency. A CNOA is used to decrease the errors due to GB and improves the frequency performance of the oscillator.