Driving circuit of magnetic field sensor based on amorphous filler metal and application method of driving circuit

Abstract

The invention discloses a driving circuit of a magnetic field sensor based on amorphous filler metal and an application method of the driving circuit. The driving circuit comprises a magnetic core motivation portion, a magnetic core replacement portion, a signal sampling and amplifying portion and a power source portion. A symmetric difference sampling circuit structure is adopted, and the charge injection effect brought by an analogue switch or a field effect transistor is eliminated. A current is exerted in metal receiving coils to replace magnetic cores, and therefore the magnetic-lag of the magnetic cores is removed; the even number of series-connection magnetic cores and a metal receiving coil structure in a symmetric winding manner are adopted, and therefore the inductive coupling effect between the magnetic cores and the receiving coils is eliminated, and the capacitive coupling effect of motivation current on the metal receiving coils is reduced, so that the signal-to-noise ratio and the linearity of output signals of the sensor are improved; each magnetic core is segmented into a plurality of isometric small segments, and the magnetic field detection range and the magnetic field sensitivity of the sensor can be conveniently controlled.

Description

technical field [0001] The invention belongs to the field of magnetic field sensors, in particular to a drive, signal acquisition circuit and application method of a high-sensitivity magnetic field sensor based on an amorphous alloy material. Background technique [0002] In the prior art, a single (or multiple parallel) high-permeability amorphous wire, amorphous film or amorphous strip is generally used as the magnetic core, and a receiving coil or a receiving coil+feedback compensation coil is wound around the structure. By flowing a high-frequency alternating current or high-frequency pulse current on the magnetic core as an excitation, and detecting the voltage signal on the receiving coil at this time to sense the external magnetic field in the length direction of the magnetic core, the voltage signal on the receiving coil is the same as Corresponds to the magnitude of the applied magnetic field. [0003] There are following deficiencies in the prior art: [0004] 1....

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Problems solved by technology

The induced voltage will be superimposed on the final output signal, causing output signal distortion and reducing the signal-to-noise ratio of the output signal

[0005] 2. Under the structure adopted in the prior art, due to the parasitic capacitance between the receiving coil and the magnetic core, when an excitation current flows through the magnetic core, capacitive coupling will occur between the magnetic core and the receiving coil, so that the receiving coil A coupling voltage is formed on the top, which will be superimposed on the final output signal, reducing the signal-to-noise ratio of the output signal and even causing saturation of the amplifier output

[0006] 3. Due to the multi-domain structural characteristics of the amorphous wire, amorphous film or amorphous tape magnetic core, the magnetic field sensors developed by using the existing technology all have hysteresis effect, that is, after the magnetic core is magnetized by the external magnetic field, the sensor output will be phenomenon of shifting

[0007] 4. The peak voltage sampling circuit used in the prior art uses an analog switch (or field effect transistor) to sample the voltage signal on the receiving coil, because the analog switch (or field effect transistor) has a "charge injection effect (Charge Injection Effect)" , that is: as the analog switch (or field effect transistor) is turned on or off, a small amount of charge will be capacitively coupled from the control terminal to the sampling signal, and the injection amount of the charge will vary with the magnitude of the voltage signal on the receiving coil, This distorts the sampled voltage signal and affects the linearity of the sensor output

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