新型微弱电流检测前置放大电路设计

针对常规微弱电流测量电路输入信号范围窄和微弱电流信号容易淹没在背景噪声、元器件固有噪声、电源噪声等干扰中而影响测量结果正确性问题,设计了一种新型微弱电流检测前置放大电路。该设计在分析常规跨阻抗法、对数压缩法前置放大器优缺点的基础上,通过改进设计电路和增加开关消噪电路,加宽了输入电流的测量范围、降低了检测系统的噪声影响、提高了检测速度。实验表明该电路具有较强的噪声抑制能力和较高的检测精度,有一定的实用价值。

Design of a High Precision and Wide Range Weak Current Detection Preamplifier Circuit

For the weak current signal is interfered easily by background noise, noise inherent in the compo-nents, power supply noise and so on. Sometimes the weak useful signal may be submerged in them, thus the measurement outcomes are often inaccuracy. In order to solve the problem, a new weak current detection pre-amplification circuit design is put forward. The design is based on the analysis of trans-impedance method, logarithmic compression method of pre amplifier. Through the improvement of circuit and the application of the switching noise elimination circuit, it reduces the noise of the detection system, widens the measurement range of the input signal and improves detection speed. Experimental results show that the circuit has strong noise suppression ability and high detection accuracy, and it has a certain practical value in weak current detection.