空间粒子探测器中一种微电流测量电路设计

为了实现对空间粒子探测器中弱电流的测量,设计了以I-V变换、电压线性放大、二阶低通滤波和带阻滤波为主要结构的弱电流测量电路。通过I-V变换原理分析,为使电流信号尽量无失真地转变为电压信号,提出了选用高输入阻抗、高准确度的运放来构成I-V变换电路。根据弱电流的特性,从电路结构、参数设计方面,讨论了电路中噪声抑制和隔离的措施,来提高测量电路的性能。以高准确度运算放大器为核心部件,完成整个实际电路。该电路测量范围为10-7A^10-12A,最小可分辨电流为10-13A,响应时间不超过5ms,还具有漂移低、稳定性好以及价格低廉的优点。

Design of Weak Current Measurement Circuit in Space Particle Detector

In order to measure the weak current in space particle detector, a measurement module is designed for the very weak current measurement, it includes I-V converter, amplifier stage circuit and filter. In order to gain voltage from I-V converter,a very high in put impedance and high accuracy operational amplifier is combined in the I-V converter circuit. According to the characteristics of low current circuit structure and parameters, from design, discusses circuit noise and the isolation of measures to improve the measurement circuit performance. Gives the design of the weak signal detection pre-amplifier using the high accuracy operational amplifier as the core circuit. Results show the current of measuring range is from 100nA to 1 pA. The resolution is 10-13A, the response time is less than or equal 5ms, it has low excursion, well stability and low price and so on.