基于PI闭环控制的AMR磁阻传感器信号调理电路  

Signal Conditioning Circuit of AMR Magnetoresistive Sensor Based on PI Closed-Loop Control

作　　者：谭超[1] 杨哲 潘礼庆[2] 龚晓辉 乐周美 TAN Chao;YANG Zhe;PAN Liqin;GONG Xiaohui;YUE Zhoumei(College of Electrical Engeering & New Energy,China Three Gorges University,Yichang Hubei 443002,China;College of Science,China Three Gorges University,Yichang Hubei 443002,China)

机构地区：[1]三峡大学电气与新能源学院,湖北宜昌443002 [2]三峡大学理学院,湖北宜昌443002

出　　处：《传感技术学报》2019年第7期1003-1008,共6页Chinese Journal of Sensors and Actuators

基　　金：湖北省弱磁探测工程技术研究中心(三峡大学)开放基金项目(2018MKF01)

摘　　要：为了提高磁场测量精度,提出一种基于PI闭环控制的AMR磁阻传感器信号调理电路。该电路由前置放大器、开关同步检波、积分电路和闭环反馈电路组成。首先通过选取较小的前置放大器增益,以降低对传感器输出噪声的放大;然后利用积分器对放大后信号进行积分,得到积分电压;最后,将积分电压进行V/I转换,并将电流接入HMC1001偏置电流带,实现闭环反馈,以抵消外部待测磁场,当电路平衡时,传感器工作于零场,积分输出电压正比于待测磁场。与开环结构对比实验结果表明:在相同的灵敏度条件下,闭环式信号调理电路噪声功率谱密度为40 pT/√ Hz @1 Hz,并且与开环式的信号调理电路相比,它的输出信号信噪比提高了15.55 dB。In order to improve the accuracy of magnetic field measurement,a signal conditioning circuit of AMR reluctance sensor based on PI closed-loop control is proposed.The circuit consists of a preamplifier,a switch synchronous detection circuit,an integral circuit and a closed-loop feedback circuit.Firstly,a smaller preamplifier gain is selected to reduce the amplification of sensor output noise;then,the integrated voltage is obtained by integrating the amplified signal with an integrator;finally,the current,which is produced by V/I converter and decided by the output voltage of integrator,is provided to HMC1001 bias current band to generate feedback magnetic field.When the circuit is balanced,the sensor works at zero magnetic field,and the integral output voltage is proportional to the magnetic field to be measured.Compared with the open-loop structure,the experimental results show that,at the same sensitivity condition,the noise power spectral density of the proposed circuit is 40 pT/√ Hz @1 Hz,and Compared with the open-loop signal conditioning circuit,the output signal-to-noise ratio of the proposed circuit is increased by 15.55 dB.

关 键 词：AMR磁阻传感器 信号调理电路 噪声功率谱密度 信噪比 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]