运放电压衰减器阶跃响应分析与改进

Analysis and Improvement of OP Amp Voltage Attenuator's Step Response

普通运放电压衰减器输出容易产生超调或振荡现象,基于运放二阶模型论述了该电压衰减器阶跃响应产生超调的原因,并通过对电压衰减器取不同衰减阻值,分析输出波形的不同,得出负载过重是该电路输出产生振荡的重要原因。最后从电路负载角度给出了用电压跟随器实现衰减器的改进设计方案,该设计经实验证明可很好地抑制输出振荡现象。

The ordinary voltage attenuator with operational amplifier is prone to generate overshoot or oscillation. Based on a second-order model of the operational amplifier, the paper elaborates the reason for the step response overshoot of the voltage attenuator, and concludes that overloading is the important cause of the circuit outputting oscillation by analyzing the difference of the voltage attenuator＇s output waveform in different attenuation resistances. Finally, the paper gives an improvement design with the voltage follower at the point of the circuit＇s load. The design is proved to inhibit the oscillation output effectively.