A Closed-Loop Operation to Improve GMR Sensor Accuracy

Abstract

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High Sensitivity Differential Giant Magnetoresistance (GMR) Based Sensor for Non-Contacting DC/AC Current Measurement

“…Magnetoresistive sensors (MR) made from magnetic layers and based on anisotropic magnetoresistance (AMR) [6][7][8][9], giant magnetoresistance (GMR) [10][11][12][13][14][15], and the tunneling magnetoresistance effect (TMR) [16] are now extensively studied and used for detection of DC/AC currents.…”

“…GMR sensors offer high sensitivity, wide frequency range, small size, low power consumption, and they are compatible with many other state-of-the-art technologies [13]. GMR sensors also have a number of drawbacks, from which we can note nonlinearity, hysteresis, offset, and a temperature dependent output that can reduce measurement accuracy [14]. In addition, the output of some of GMR sensors is unipolar, which limits its application in AC measurements [2].…”

“…Using a bias field parallel to the sensitive axis can shift the operating point of the sensor to the linear region, thus reducing the hysteresis behavior and creating a bipolar signal. This field can be created either by using a permanent magnet or a coil system with DC, AC, or short pulse currents which can have either open or closed-loop control [14]. Optimization in terms of signal measurement (such as using a differential measurement method) and acquisition can also be performed.…”

“…Regarding the application of GMR sensors as current sensors, a multitude of studies have been performed to improve their characteristics. In [14], a closed-loop operation was used to improve the linearity of the GMR sensor. Hysteresis modelling compensation is used in [11] to reduce hysteresis and temperature dependency.…”

Giant Magnetoresistance Sensors Based on Ferrite Material and Its Applications

“…Recently, Li and Dixon [27] have proposed the use of the closed-loop circuit to improve the measurement accuracy of GMR sensor. By using the biasing coil and feedback Differential-to-single ended Wheatstone bridge output by using a voltage differential amplifier (adopted from Ref.…”