一种基于Cortex-M3的pA级电流检测系统设计

Design of a pA Current Detection System Based on Cortex-M3

针对光电、MEMS等传感器涉及到的微弱电流信号,基于STM32F103设计了一套pA级电流检测系统,包括电流检测硬件和功能软件两部分,硬件采用USB供电,应用ADA4530+AD7172设计微弱电流采样电路,并介绍了关键参数的选取原则和AD配置流程。TencentOS tiny+FatFs+ADI驱动实现了下位机数据采样、SD卡存储和传输功能,基于LabVIEW+Java开发了上位机显示和数据库存储程序,并以S1226为例进行了测试,分析表明总误差不超过150 fA,满量程为300 ppm,能够满足检测需求,具有一定的实用价值。

Aiming at the weak current signals involved in the sensors such as photoelectric and MEMS,a pA current detection system was designed based on STM32F103,including current detection hardware and functional software.The hardware was powered by USB,ADA4530+AD7172 were adopted to design weak current sampling circuit,and the selection principle of key parameters and AD configuration process were described in detail.TencentOS tiny+FatFs+ADI driver implemented the functions of data sampling,SD storage and transmission,upper computer display and database storage programs were developed based on LabVIEW+Java.Taking S1226 as an example,it showed that the total error is no more than 150fA,and it is 300ppm at full range,which could meet the detection requirements and has certain practical value.