一种方波调制的TMR磁场探测系统设计与实现  

Design and realization of square wave modulated TMR magnetic field detection system

作　　者：赵宇红[1] 张天洋 崔岩 李博[2] 闫江 ZHAO Yuhong;ZHANG Tianyang;CUI Yan;LI Bo;YAN Jiang(School of Electronic and Information Engineering,North China University of Technology,Beijing 100043,China;Key Laboratory of Silicon Device Centre,Institute of Microelectronics of the Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]北方工业大学信息学院,北京100043 [2]中国科学院微电子研究所硅器件中心重点实验室,北京100029

出　　处：《现代电子技术》2020年第1期148-152,共5页Modern Electronics Technique

基　　金：国家自然科学基金（61874135）;北京市自然科学基金（4182021）

摘　　要：为了实现对磁场信号的高精度检测,利用隧道磁阻式磁传感器,设计并实现了一种精确分辨微弱磁场场信号的锁相放大系统。使用方波调制传感器输出信号,并利用Σ-Δ型ADC实现平均下抽取结构,抑制方波带来的高次谐波干扰,提高了ADC的有效分辨率,降低了系统运算量。通过理论与实验分析,验证了系统可以有效抑制噪声与温漂对测量精度的影响,并可精确标定nT级磁场。A lock⁃in amplification system for accurately distinguishing weak magnetic field signals was designed and realized by TMR(tunnel magnetoresistance)magnetic sensor to realize the high⁃precision detection of magnetic field signals.In this system,the sensor output signal is modulated by square wave,and the average⁃decimation structure is realized byΣ⁃ΔADC(analog to digital converter)to suppress the high⁃order harmonic interference caused by square wave,which improves the effective resolution of the ADC and reduces the system operation amount.It is verified by theoretical and experimental analysis that the system can effectively suppress the influence of noise and temperature drift on the measurement accuracy,and can accurately calibrate the nT magnetic field.

关 键 词：隧道磁阻式磁传感器 微弱信号 过采样 方波调制 锁相放大器 Σ-Δ模数转换器 

分 类 号：TN03-34[电子电信—物理电子学] TP212[自动化与计算机技术—检测技术与自动化装置]