Low-frequency noise suppression device and method for tunnel magnetoresistive effect sensor

Abstract

The invention discloses a low-frequency noise suppression device and method for a tunnel magnetoresistive effect sensor. The device comprises a sensitive structure, wherein the sensitive structure comprises a micro coil, the tunnel magnetoresistive effect sensor and a soft magnetic conductor which are sequentially disposed on a same horizontal line; the axial direction of the micro coil is perpendicular to the horizontal line; the micro coil and the tunnel magnetoresistive effect sensor are spaced by a preset distance, and the sensitive direction of the tunnel magnetoresistive effect sensor isperpendicular to the axial direction of the micro coil; an oscillating circuit, which is connected to the micro coil to drive the micro coil to generate a periodic alternating magnetic field; and a low-noise circuit, wherein the low-noise circuit is connected with the tunnel magnetoresistive effect sensor and is used for processing an output signal of the tunnel magnetoresistive effect sensor. According to the low-frequency noise suppression device for the tunnel magnetoresistive effect sensor provided by the invention, low-frequency noises can be suppressed, the signal-to-noise ratio and thedetection sensitivity are improved, the performance is stable, and the cost is low.

Description

technical field [0001] The invention relates to the technical field of tunnel magnetoresistance effect sensors, in particular to a low-frequency noise suppression device and method for tunnel magnetoresistance effect sensors. Background technique [0002] The tunnel magnetoresistance effect sensor is a sensor that converts the sensed magnetic field intensity change into an electrical signal change. As a measuring device, the tunnel magnetoresistance effect sensor has many advantages such as high magnetic field sensitivity, low power consumption, good temperature stability, and small size. Advantages, used in modern industry and electronic products for weak magnetic field detection and measurement of physical parameters such as current, position, and direction. [0003] Although the sensitivity of the tunnel magnetoresistance effect sensor to detect the magnetic field is high, its output noise seriously affects the resolution, especially the 1 / f noise at low frequency. Since...

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Problems solved by technology

[0003] Although the sensitivity of the TMR sensor to detect magnetic fields is high, its output noise seriously affects the resolution, especially the 1 / f noise at low frequency

Since the size of the 1 / f noise is opposite to the working frequency of the sensor, the 1 / f noise is very high when the frequency is low. The detection accuracy at high frequency is two orders of magnitude worse, which severely limits its ability to detect static or low-frequency magnetic fields, and the 1 / f noise depends on the internal magnetic structure and will change with the bias voltage, so it cannot pass through the sensor The offset modulation is eliminated, therefore, the noise in the low frequency band seriously affects the detection performance of the sensor

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