运算放大器工作原理的深度剖析

Deep understanding on the principle of operational amplifier

通过引入杠杆原理深度剖析运算放大器的工作特性,给出比较器与放大器、积分与比例积分电路、微分与比例微分电路、PID调节器的电路运算本质。如比较器与放大器的本质区别是反馈形式不同,积分电路的积分过程是恒流源对电容的充电过程,比例积分比积分快及比例微分比微分慢是因为串联电容的电阻起分压作用等。将电路原理映射到杠杆原理中,获得输入与反馈电路中的电阻电容对电路增益及相位的变化规律,用Saber软件仿真,结果验证了理论分析的正确性和有效性。

The performance characteristics of the operational amplifier are analyzed deeply by introducing the lever principle. The circuits working essence of comparator and amplifier, integral and proportional integral circuit, differential and proportional differen- tial circuit, PID controllers are presented. For instance, the essential difference between comparator and amplifier is its different feedback forms, integral process of the integral circuit is a constant current source charges the capacitor, proportional integral circuit is faster than pure integrator and proportional differential circuit is slower than pure differentiator since the resistor in series with the capacitor shares the voltage. These circuits are mapped to the lever principle, and the impact of resistance and capacitance in input and feedback circuits on the circuits＇ gain and phase are acquired. The correctness and validity of the theoretical analysis are verified by Saber simulation.