A deep pulse current annealing, signal conditioning and acquisition method and device for permalloy

Abstract

The invention discloses a deep pulse current annealing, signal conditioning and acquisition method and device for permalloy. First, a clock signal is provided by a signal source to input a switch to control a signal generator to generate a rectangular pulse voltage signal generator to turn on and off two transistors inside the generator. The logic control signal required for the off action; secondly, the constant voltage source required by the rectangular pulse voltage signal generator is provided by the non-inductive charge pump boost; then the rectangular pulse voltage signal generator generates the rectangular pulse voltage signal PUL to drive the RC pulse current signal to generate The alloy current strip in the device generates periodic tip pulses, which in turn generate an over-range strong magnetic field whose direction changes periodically, so that the output signal of the permalloy Wheatstone bridge placed near the alloy current strip undergoes periodic reversal; The differential output signal of the permalloy Wheatstone bridge is amplified and conditioned, and the analog-to-digital converter is synchronously collected and sent to the microprocessor after magnetization and annealing. The invention can effectively improve the measurement accuracy of the permalloy magnetoresistive sensor.

Description

technical field [0001] The invention relates to a method and device for magnetizing annealing, output signal conditioning and acquisition of an iron-nickel alloy magnetoresistive element applied to a magnetoresistive sensor. Background technique [0002] Permalloy, a ferromagnetic metal with magnetoresistive effect, is often used as the core magnetoresistive element of magnetoresistive sensors. Before leaving the factory, permalloy components are often magnetized by applying a strong magnetic field in the direction of the easy magnetization axis, so that the orientation of the internal magnetic domains tends to be the same, and the external magnetic field is displayed. This characteristic can be maintained for several years until there is an external interference magnetic field. The resistance of the permalloy element depends on the angle between the current and the magnetization direction. When the current is parallel to the magnetization direction, the resistance is the la...

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Problems solved by technology

[0005] In addition, the differential voltage signal output by the above-mentioned electric bridge composed of permalloy magnetoresistive elements is a weak signal with a variation range of mV level. At the same time, the high output impedance makes it difficult for the signal to be accurately collected by the signal collection circuit.

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