摘要
针对ppb级气体检测时所产生短时间的fA级电流信号,对应信号采集系统必须达到fA级的采集能力和分辨率,并有较短的采集时间。因此,采用超低偏置电流的ADA4530运算放大器芯片作为核心搭建跨阻放大电路对微电流进行放大,并辅以镂空、屏蔽、Guard环以及辅助电路等方法减小输入噪声,提高系统稳定性。实验表明:微电流采集系统的空载基线噪声水平约为8.1 fA,最小分辨率为2.025 fA,响应时间小于200 ms,检测范围为-180.32~179.97 pA,检测大于100 fA电流时误差小于4%。
For the fA current signal generated during the ppb level gas detection for a short time,the corresponding signal acquisition system must reach the fA level acquisition capability and resolution,and have a short collection time.Therefore,the ADA4530 operational amplifier chip with ultra-low bias current is used as the core to build a cross-resistance amplifier circuit to amplify the micro-current,and it is supplemented by hollow,shield,Guard ring and auxiliary circuit to reduce the input noise and improve the stability of the system.Experiments show that the no-load baseline noise level of the micro-current acquisition system is about 8.1 fA,the minimum resolution is 2.025 fA,the response time is less than 200 ms,the detection range is-180.32~179.97 pA,and the error is less than 4%when the detection current is greater than 100 fA.
作者
牛致远
马天军
孙建海
周天烨
孔繁岩
NIU Zhiyuan;MA Tianjun;SUN Jianhai;ZHOU Tianye;KONG Fanyan(Institute of Aerospace Information Innovation,Chinese Academy of Sciences;School of Electronic,Electrical and Communication Engineering,University of Chinese Academy of Sciences;Quanzhou University of Information Engineering;Shandong Lunan Ruihong Chemical Instrument Co.,LTD)
出处
《仪表技术与传感器》
北大核心
2025年第7期30-36,共7页
Instrument Technique and Sensor
基金
国家重点研发计划项目(2022YFF0708801)
国家自然科学基金项目(62174163)。
关键词
跨阻放大电路
微电流
电流采集
cross-resistance amplifier circuit
micro current
current acquisition
