Weak current detection circuit

The invention provides a weak current detection circuit, which can realize weak current signal detection considering a measurement dynamic range and resolution. In order to have high current resolution and give consideration to an input dynamic range, a multi-range weak current extraction method is adopted, a high resistor is adopted as a transimpedance, and wide-range and high-resolution current pickup is realized by using an automatic range conversion technology and a high-resolution analog-to-digital converter. Experimental results show that the resolution of the measuring method can reach 1pA, the measuring dynamic range reaches 104, and the measuring method can be applied to a gas chromatographic detector, an electrochemical gas sensor signal detection circuit and the like. 本发明提出了一种微弱电流检测电路，能够实现兼顾测量动态范围和分辨力的微弱电流信号检测。本发明为了具有较高的电流分辨力同时兼顾输入动态范围，采用多量程微弱电流提取方法，采用高电阻作为跨阻，使用自动量程转换技术和高分辨力的模数转换器实现宽范围、高分辨力的电流拾取。实验结果表明，该测量方法的分辨力能够达到1pA，测量动态范围达到104，可应用于气相色谱检测器、电化学气体传感器信号检测电路等。