A system and method for reducing noise of tunneling magnetoresistance sensor

A technology of sensor noise and tunnel magneto-resistance, applied in instruments, measuring magnetic variables, measuring devices, etc., can solve problems such as poor noise reduction effect

Active Publication Date: 2021-05-18
HUAZHONG UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Aiming at the above defects or improvement needs of the prior art, the present invention provides a system and method for reducing the noise of the tunnel magnetoresistive sensor, which is used to solve the technical problem of poor noise reduction effect in the prior art due to the need to wind multi-turn coils

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  • A system and method for reducing noise of tunneling magnetoresistance sensor
  • A system and method for reducing noise of tunneling magnetoresistance sensor
  • A system and method for reducing noise of tunneling magnetoresistance sensor

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Embodiment 1

[0036] A system for reducing noise in tunneling magnetoresistive sensors such as figure 1 As shown, it includes: a non-coil shielding cylinder 1 and a drive circuit 2; wherein, the material of the non-coil shielding cylinder 1 is a high permeability soft magnetic material, that is, a soft magnetic material with a relative permeability greater than 5000. In this embodiment, the high magnetic permeability soft magnetic material is 1J85 type permalloy, and its magnetic permeability will increase and even be saturated under the influence of a weaker magnetic field; when a small current is passed through, a small induced magnetic field is generated , its magnetic permeability will enter the saturation region and decrease with the increase of the induced magnetic field, and the corresponding magnetic shielding ability will also decrease. There are circuit connection points on the non-coil shielding cylinder 1, which can be connected to high-frequency alternating current to realize h...

Embodiment 2

[0042] A method for reducing the noise of a tunnel magnetoresistive sensor, comprising the steps of:

[0043] S1. Place the TMR sensor to be processed in the center of the non-coil shielding cylinder;

[0044] S2. Pass AC current to the non-coil shielding cylinder. Based on the supersaturation characteristics of the high permeability soft magnetic material of the non-coil shielding cylinder, its shielding ability will undergo high-frequency changes, thereby reducing the DC magnetic field to be measured outside the shielding cylinder. Transform into a high-frequency AC magnetic field to reduce the 1 / f noise of the TMR sensor;

[0045] S3. By performing phase-sensitive detection and low-pass filtering on the AC output of the TMR sensor, the sum-frequency signal is filtered out, and the difference-frequency signal is retained, so as to further filter out the 1 / f noise of the TMR sensor.

[0046] Further, the TMR sensor is placed in the center of the non-coil shielding cylinder, ...

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Abstract

The invention discloses a system and method for reducing the noise of a tunnel magneto-resistance sensor, comprising: a non-coil shielding cylinder and a driving circuit; wherein, the material of the non-coil shielding cylinder is a high magnetic permeability soft magnetic material; the TMR to be processed The sensor is placed in the center of the non-coil shielding cylinder; the output end of the TMR sensor is connected to the input end of the drive circuit; the non-coil shielding cylinder is based on the supersaturation characteristics of the high magnetic permeability soft magnetic material. The ability to change at high frequency, so that the DC magnetic field to be measured by the TMR sensor will be converted into a high-frequency AC magnetic field, and the 1 / f noise of the TMR sensor will be reduced; the drive circuit will perform phase-sensitive detection and low-frequency detection on the output signal of the TMR sensor based on the reference signal. Through filtering, the sum frequency signal is filtered out, the difference frequency signal is retained, and the 1 / f noise of the TMR sensor is further filtered out. The non-coil shielding cylinder in the present invention does not need to be wound with multi-turn coils, does not introduce new noise, and has a good noise reduction effect.

Description

technical field [0001] The invention belongs to the field of magnetic sensor noise reduction, and more specifically relates to a system and method for reducing noise of a tunnel magnetoresistance sensor. Background technique [0002] Tunneling Magneto Resistive (TMR) is a magnetic field measurement sensor with high sensitivity, high response frequency, and low power consumption. application. TMR sensor has many advantages, but the noise is relatively large, so it is of great significance to study a method to reduce the noise of tunnel magnetoresistive sensor. [0003] Existing methods for reducing the noise of tunnel magnetoresistive sensors include sigma-delta circuit modulation method, magnetic tunnel junction array method, MEMS type magnetic flux modulation method and magnetic shield chopper modulation method. Among them, the sigma-delta circuit modulation reduces noise through oversampling and noise shaping techniques, but the multi-order sigma-delta circuit has a comp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R33/09G01R1/18
CPCG01R1/18G01R33/098
Inventor 欧阳君李佳旭杨晓非陈实姚行中徐俊周晓华
Owner HUAZHONG UNIV OF SCI & TECH
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