pA级超微弱电流前置放大电路的电流噪声及等效误差分析方法

Current Noise and Equivalent Error Analysis of pA Level Current Preamplifier Circuit

根据静电测量领域的高阻型Ⅰ-Ⅴ电路模型,对pA级电流前置放大(PA)电路电流噪声的误差影响进行分析。根据叠加定理,对放大电路器件的各分项等效电流噪声及其误差进行综合计算,得到总的系统测量误差工程估算。基于该分析方法对测量电路中运放器件参数选型给出应用实例,PA电路实测结果验证了该分析方法的有效性。

Based on the high resistanceⅠ-Ⅴcircuit model in the field of electrostatic measurement,the error influence of current noise in pA level weak current preamplifier(PA)circuit is analysed.According to the superposition theorem in circuit,the sub item equivalent current noise and the error of amplification circuit devices are comprehensively calculated,and the total engineering estimation of system measurement error is obtained.On the basis of this analysis method,an application example of parameter selection of operational amplifier in measurement circuit is given.The measured results of PA circuit verify the effectiveness of this analysis method.