CN207081821U - A kind of premodulated magnetic resistance sensor - Google Patents
A kind of premodulated magnetic resistance sensor Download PDFInfo
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- CN207081821U CN207081821U CN201720350249.4U CN201720350249U CN207081821U CN 207081821 U CN207081821 U CN 207081821U CN 201720350249 U CN201720350249 U CN 201720350249U CN 207081821 U CN207081821 U CN 207081821U
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Abstract
The utility model discloses a kind of premodulated magnetic resistance sensor, a substrate is provided with X/Y plane, magneto-resistor sensing element, modulator, electric connector, electric insulation layer and bonding welding pad deposit over the substrate, the sensing of the magneto-resistor sensing element is oriented parallel to X-axis, magneto-resistor sensing element is connected in series into magneto-resistor sensing element string, described modulator is by multiple modulator bar constructions, described modulator rod is by FM1 layers, NM layers and FM2 layers three-decker are formed, the current path of snakelike shape is electrically connected to form between the end of described modulator rod, one layer of electric insulation layer is provided between described modulator rod and magneto-resistor sensing element, described electric insulation layer separates described modulator rod and described magneto-resistor sensing element.The utility model ensures that modulated signal is operated in the range of linearity of magnetic field sensor by modulating electric current, further changes magnetic conductivity by modulating magnetic field, and then realize the suppression of noise.
Description
Technical field
It the utility model is related to a kind of magnetic resistance sensor, more particularly to a kind of premodulated magnetic resistance sensor.
Background technology
Magnetic resistance sensor is limited by 1/f noise, and resolution limiting is in a low frequency.Modulate magnetic field sensor
Technology have evolved to measurement signal be converted into higher frequency relative to sensor intrinsic noise, can so bypass and pass
The 1/f noise of sensor.
In the prior art including the use of electromagnetic flux field concentrator, further, by using MEMS relative to each other with swing
Mode movable sensor and electromagnetic flux field concentrator, outside in sensor provide the flux concentrator of volume larger, and used
A kind of coil being arranged on around electromagnetic flux field concentrator is periodically permeated.
In above-mentioned two situations, in order to which the magnetic field that periodic variation will measure, the magnetic field pass through biography
Sensor senses, and referred to as a kind of method of premodulated can be then modulated by the output of sensor signal, and this will sensing
Device signal is converted to higher frequency, and now, the noise of sensor becomes smaller.
Modulate magnetic field must be enough it is small, just do not cause the noise of sensor element so.By larger periodic
Magnetic field is modulated in itself to sensor can both cause Barkhausen noise, and if when amplitude is sufficiently large, it will also be produced
The non-linear modulation of transducer sensitivity, and the low frequency thermomagnetion noise that non-linear modulation is mixed with sensor enters modulation letter
Number sideband.When the modulation magnetic field of minimum occurs in the sensor, simultaneously therefore optimum signal-noise ratio just generates optimal noise reduction,
These also just correspond to the peak amplitude of detected signal.
In addition, noise reduction is beneficial to reduce sensor 1/f noise, this is realized based on following factors：Appropriate sensor
Biasing；Appropriate sensor material；The size of enough sensors.
Finally, and when in sufficiently high frequency modulation(PFM), so that input signal occurs in the white noise region of sensor；
The resistance of sensor is low, and such Johnson noise is low；The high sensitivity of sensor, such equivalent input noise are small；According to certain
Voltage or current offset sensor, will not so cause shot noise, shot noise has exceeded hot Johnson of sensor
Noise, noise reduction have reached maximization.
Modulator approach of the prior art is：Mobile electromagnetic flux field concentrator or relative to electromagnetic flux field concentrator movable sensor,
Both approaches are too complicated, and expense is very high；Sensor is placed in a big radome, radome periodically oozes
Thoroughly, however, radome is in the outside of sensor in this method, such volume can become very big, also costly.
Utility model content
In order to solve the above-mentioned technical problem, the utility model proposes a kind of premodulated magnetic resistance sensor.This practicality is new
Type is realized according to following technical scheme：
A kind of premodulated magnetic resistance sensor, is provided with a substrate on X/Y plane, magneto-resistor sensing element, modulator,
Electric connector, electric insulation layer and bonding welding pad are deposited over the substrate, and the sensing direction of the magneto-resistor sensing element is put down
Row is in X-axis；
The magneto-resistor sensing element is connected in series into magneto-resistor sensing element string, described magneto-resistor sensing element string electricity
Sensor bridge is connected into, the sensor bridge is push-pull type half-bridge circuit or push-pull type full-bridge circuit；Described magneto-resistor
Sensing element string electrically connects with described bonding welding pad so that bias voltage or electric current flow through described magneto-resistor sensing element
And detect the voltage or electric current on the magneto-resistor sensing element；
Described modulator electrically connects with described bonding welding pad, obtains modulating electric current from described bonding welding pad, described
Direction of the sense of current parallel to Y-axis is modulated, described modulator make it that modulating electric current passes through soft iron magnetic flux concentrator week
The conductor enclosed, magnetic field is produced around soft iron magnetic flux concentrator to modulate the magnetic conductivity of soft magnetism flux concentrator, described tune
Be provided with one layer of electric insulation layer between device processed and magneto-resistor sensing element, described electric insulation layer by described modulator with it is described
Magneto-resistor sensing element separate.
Preferably, described magneto-resistor sensing element is AMR, GMR or TMR magnetic induction part；Described modulator by
Multiple modulator bar constructions, the structure of described modulator rod is rectangular strip, and its major axis is put down parallel to Y direction, its short axle
Row is set in the form of an array in X-direction, multiple described modulator rods, there is gap, the gap between the modulator rod
Spacing distance direction prolong X-direction, the electricity of snakelike shape is connected between the end of described modulator rod by electric connector
Flow path.
Preferably, described modulator rod is made up of FM1 layers, NM layers and FM2 layer three-deckers, wherein FM1 layers and FM2
Layer is soft ferromagnetic layer, and NM layers are ordinary metal layers；The material of the NM layers is ruthenium or copper, and the thickness of the NM layers is less than 5nm,
Antiferromagnetic RKKY couplings between the FM1 layers and the FM2 layers be present.
Preferably, described electric connector is upper surface, the following table of metal, described electric connector and described modulator
Face or side surface are connected；
Or described electric connector etches from the three-decker of FM1 layers, NM layers and FM2 layers.
Preferably, described modulator includes current-carrying coil and ferromagnetism cuboid, and described current-carrying coil is positioned at ferromagnetic
The top of property cuboid, described current-carrying coil are connected with described bonding welding pad.
Preferably, described sensor also includes exchange reference power supply, and described exchange reference power supply is with frequency f periodicity
Ground drives modulator rod, analog front circuit, low pass filter and the frequency mixer of the sensor, described AFE(analog front end) electricity
Road includes FEP and amplifier, and described FEP couples with the output capacitor of magnetic resistance sensor, described
The input of frequency mixer be electrically connected to described exchange reference power supply and described FEP output end, described low pass
The output end of frequency mixer described in the input electrical connection of wave filter, the output end of described low pass filter provide an output
Signal, described output signal are corresponding with the amplitude and polarity in magnetic field that described magneto-resistor sensing element is detected.
Preferably, Optimal Filter is also included, the Optimal Filter is with exchanging reference power supply signal or described
The input signal electrical connection of frequency mixer；The Optimal Filter in exchange reference power supply signal by entering mixting circuit
Component frequency component is removed before, and to adjust by way of changing exchange reference power supply signal as ac voltage signal
State reference power supply signal.
Preferably, described exchange reference power supply signal is unipolar, described low pass filter and described mixing
The output end connection of device, described low pass filter have the low-frequency cut-off frequency that frequency is F.
Preferably, described exchange reference power supply signal is that ambipolar, described magnetic resistance sensor also includes frequency multiplication
Device, described frequency multiplier electrically connect with the described input for exchanging reference power supply and described frequency mixer, described low pass
Wave filter is connected with the output end of described frequency mixer, and described low pass filter has the low-frequency cut-off frequency that frequency is 2F.
Preferably, the sensor bridge includes one chip, form sensor bridge bridge arm be deposited on it is described single
On chip；Or the sensor bridge includes the chip of two or more interconnection, each independent chip includes
Magneto-resistor sensing element string, described magneto-resistor sensing element string, which is electrically connected, is connected into the bridge arm of one or more sensor bridges.
Preferably, when the exchange reference power supply signal is located at operating frequency range, described magnetic resistance sensor member
Part produces white noise acoustic frequency and is much larger than 1/f noise frequency.
Preferably, described FM1 layers and described FM2 layers have different remanent magnetism thickness product Mrt, when without externally-applied magnetic field,
Even if it is maximum to exchange reference power supply signal, the modulation electric current is also minimum in magnetic field caused by sensing station.
Compared with prior art, the utility model has following skill to a kind of premodulated magnetic resistance sensor of the present utility model
Art effect：
The utility model uses the FM stacks of RKKY couplings, by coming from described in the modulation electric current change of modulator
The magnetic conductivity of magnetic resistance sensor, and therefore modulate magnetic field；The utility model can carry out letter before sensor element detection
Number modulation, and it is described modulation electric current be able to ensure that modulated signal is operated in the range of the corresponding linear of magnetic resistance sensor；Enter one
Step realizes magnetic field modulation and noise suppressed by changing magnetic conductivity.
Brief description of the drawings
, below will be to embodiment in order to illustrate more clearly of the utility model embodiment or technical scheme of the prior art
Or the required accompanying drawing used is briefly described in description of the prior art, it should be apparent that, drawings in the following description are only
It is some embodiments of the utility model, for those of ordinary skill in the art, is not paying the premise of creative work
Under, other accompanying drawings can also be obtained according to these accompanying drawings.
Fig. 1 is the frequency of modulated signal and the relation schematic diagram of sensor noise；
Fig. 2 is the signal modulation technique schematic diagram of standard；
Fig. 3 is Johnson noise and 1/f noise with frequency change schematic diagram；
Fig. 4 is the skew schematic diagram of signal modulation and noise；
Fig. 5 is a kind of structural representation of premodulated magnetic resistance sensor of the present utility model；
Fig. 6 is a kind of sectional view of premodulated magnetic resistance sensor of the present utility model；
Fig. 7 is a kind of structural representation of modulator rod of the present utility model；
Fig. 8 is the structural representation of another modulator rod of the present utility model；
Fig. 9 is the Distribution of Magnetic Field schematic diagram of the modulator rod of the present utility model without modulation electric current；
Figure 10 is the Distribution of Magnetic Field schematic diagram of the modulator rod of the present utility model for having modulation electric current；
Figure 11 is a kind of structural representation of modulator of premodulated magnetic resistance sensor of the present utility model；
Figure 12 is the schematic diagram of the magnetic conductivity and modulation current relationship of sensor axis；
Figure 13 is the oscillogram of the modulation electric current applied；
Figure 14 is the oscillogram of magnetic conductivity change；
Figure 15 is the oscillogram of sensor gain；
Figure 16 is the input and output schematic diagram of modulation magnetic resistance sensor；
Figure 17 is unipolar first harmonic application schematic diagram of single magnetoelectricity resistance circuit of the present utility model；
Figure 18 is the ambipolar second harmonic application schematic diagram of single magnetoelectricity resistance circuit of the present utility model；
Figure 19 is unipolar first harmonic application schematic diagram of half-bridge circuit of the present utility model；
Figure 20 is the ambipolar second harmonic application schematic diagram of half-bridge circuit of the present utility model；
Figure 21 is unipolar first harmonic application schematic diagram of full-bridge circuit of the present utility model；
Figure 22 is the ambipolar second harmonic application schematic diagram of full-bridge circuit of the present utility model.
Embodiment
It is new below in conjunction with this practicality to make the purpose, technical scheme and advantage of the utility model embodiment clearer
Accompanying drawing in type embodiment, the technical scheme in the embodiment of the utility model is clearly and completely described, it is clear that is retouched
The embodiment stated is the utility model part of the embodiment, rather than whole embodiments.Based on the implementation in the utility model
Example, all other embodiment that those of ordinary skill in the art are obtained under the premise of creative work is not made, is belonged to
The scope of the utility model protection.
Fig. 1 is the frequency of modulated signal and the relation schematic diagram of sensor noise；Specifically, at position 1, low frequency signal
With bigger noise, in this case, direct current signal has very low resolution ratio；At position 2, if direct current signal is with one
Fixed frequency shift (FS) will be a kind of ideal state to white noise scope.
Fig. 2 is the schematic diagram of the modulation technique of standard, ideally, can eliminate and come from noise amplifier, mixing
The noise of device and low pass filter, this modulator needs first to modulate low noise circuit element, inclined by applying alternating voltage
Put or AC magnetic field signal carrys out modulation sensor to sensor, this can be as by desired obtained signal making an uproar from sensor
The method separated in sound, but this method can not realize the removal of sensor noise.
Wherein, resistance noise refers to the resistor random-access in a device and random fluctuation.In this application, define
For Rnoise(ω), when an electric current flows through a device, resistance noise will occur in the form of voltage noise.Further,
Voltage noise refers to that the voltage in a device is random and random fluctuation, is herein defined as Vnoise(ω)。
For a device, it is more likely that only voltage noise is without the electric current flowed through, and therefore, a device can have
For balanced voltage without resistance noise, Johnson noise is exactly an example；It is also possible to the electricity independently of bias current
Noise is pressed, Johnson noise is also an example.
Fig. 3 is Johnson noise and 1/f noise with frequency change schematic diagram.The amplitude of Johnson noise is not with biasing
Electric current changes and changed, and 1/f voltage noises change with bias current.
Johnson's spectral noise density isIt is worth noting that, this is voltage noise, it with it is attached
Frequency in figure is unrelated, wherein, the resistance R of sensor is 5K ohms, corresponding to 10nV/rtHz.
Described 1/f noise is very big in low frequency, and the amplitude of 1/f noise is determined that Johnson makes an uproar by bias voltage
Sound is independent therewith；Wherein, 1/f noise occurs in the form of resistance fluctuation, the possible mechanism of action of many of which；But
It is for Sensor Design, it is that resistance fluctuation determines it is how to be suppressed, and specific mechanism of action is unimportant.
Analysis is given below, it was demonstrated that sensor bias modulation is inoperative：It is assumed that the output of sensor be signal with
The combination of noise：
Wherein, H represents the magnetic field of measurement, and S represents sensitivity, Vnoise(ω) represents random sensor noise, α1Represent
Signal nonlinear factor, i are >=1 positive number,
Under a limit, Vout(ω)≈H(ω)S+Vnoise(ω)；
It is contemplated that modulation sensor is biased to change sensitivity,
Then, Vout(ω)≈H(ω)S(Ibias(ωc))+Vnoise(ω,Ibias(ωc))
However, 1/f noise occurs in the form of resistance noise, the amplitude of resistance noise depends on flows through sensor element
Bias current：
Vout(ω)≈H(ω)S(Ibias(ωc))+Rnoise(ω)Ibias(ωc)+....
Therefore, when with ωcWhen carrying out modulation sensor, it can obtain：
Vout(ω-ωc)-Vout(ω+ωc)≈H(ω){S(Ibias(0))-S(Ibias(2ωc))}+Rnoise(ω){Ibias
(0)-Ibias(2ωc)+... is then with ωcBy low pass filter, we do not see the reduction of 1/f noise,
Vout(ω-ωc)≈H(ω)S(Ibias(0))+Rnoise(ω)Ibias(0)+....
Vout(ω-ωc)≈H(ω)S+Vnoise(ω)+....
Accordingly, it can be seen that modulation sensor biasing can not reduce 1/f noise, such sensor can produce resistance and make an uproar
Sound.
It is modulated below by the way of premodulated, it is assumed that sensor output is the non-linear combination of the noise of signal,
The sensor is to use direct current biasing,
Wherein, H represents the magnetic field of measurement, and S represents sensitivity, Vnoise(ω) represents random sensor noise, α1Represent
Signal nonlinear factor, i are >=1 positive number,
The noise that can be measured under the limit and magnetic field be mutually it is independent,
Vout(ω)≈H(ω)S+Vnoise(ω)
Assuming that before sensor detects magnetic field, in ωcMagnetic field input is modulated, can so be obtained
Vout(ω)≈H(ω+ωc)S+Vnoise(ω),
Pass through ωcCarry out to VoutIt is mixed, can be obtained：
Vout(ω-ωc)-Vout(ω+ωc)≈{-H(2ωc)+H(ω)}S-Vnoise(ω+ωc)+Vnoise(ω-ωc)
+ ... eventually through low pass filter, can obtain：
Vout(ω-ωc)≈H(ω)S+Vnoise(ω-ωc)+...
So noise goes to negative frequency relative to detectable signal.
Fig. 4 is the skew schematic diagram of signal modulation and noise, and the spectrum offset of modulation is with frequencies omegacLow frequency is moved on to, is made
Into the reduction of low frequency noise.If using high modulation magnetic field, the non-linear side that sensor noise can be caused to be mixed into modulation
On frequency band, this will reduce the quantity of noise reduction.
In order to which any modulated structure can work, modulators modulate signal to be measured and not necessarily have to modulation sensor
1/f noise, still can realize the frequency shift (FS) between signal and noise, reduce the 1/f noise of system output.
Fig. 5 is a kind of structural representation of premodulated magnetic resistance sensor of the present utility model, as shown in figure 5, being put down in XY
A substrate 1 is provided with face, magneto-resistor sensing element 3, modulator rod 2, electric connector 4, sensor connecting piece 5, first are bonded
Pad 6, the second bonding welding pad 7, third bond pad 8, fourth bond pad 9 etc. are deposited on the substrate 1, magneto-resistor sensing
The sensing of element 3 is oriented parallel to X-axis；
Magneto-resistor sensing element 3 is connected in series into magneto-resistor sensing element string, and described magneto-resistor sensing element string is electrically connected
It is connected into sensor bridge；Described magneto-resistor sensing element string is by sensor connecting piece 5, with described bonding welding pad 7 and key
Close pad 8 to electrically connect so that bias voltage or electric current flow through described magneto-resistor sensing element 3 and detect magneto-resistor sensing member
Voltage or electric current on part 3, multiple described modulator rods 2 are set in the form of an array, have gap between the modulator rod 2,
X-direction is prolonged in the direction of the spacing distance in the gap, and described modulator rod 2 electrically connects with described bonding welding pad, modulation
Electric current passes through from the bonding welding pad, and the modulation current parallel is between the direction of Y-axis, the end of described modulator rod 2
The current path of snakelike shape is connected into by electric connector 4.
Wherein, described magneto-resistor sensing element 3 is AMR, GMR or TMR magnetic induction part.Described magneto-resistor sensing
Element string, which is electrically connected, is connected into push-pull type half-bridge circuit, or described magneto-resistor sensing element string is electrically connected and is connected into push-pull type full-bridge electricity
Road.
Fig. 6 is the sectional view of premodulated magnetic resistance sensor of the present utility model, in one layer of 2 disposed thereon of modulator rod
Passivation protection layer 16, in the disposed thereon upper electrode 15 of magneto-resistor sensing element 3, bottom is deposited below magneto-resistor sensing element 3
Portion's electrode 14, bottom electrode 14 are connected with substrate 1, and one layer of electric insulation is provided between modulator rod 2 and magneto-resistor sensing element 3
Layer, electric insulation layer 13 separate described modulator rod 2 and described magneto-resistor sensing element 3.Wherein, magneto-resistor sensing element
It is also provided with one layer of electric insulation layer between 3 and substrate 1,17 in figure are bonding welding pad.
Fig. 7 is a kind of structural representation of modulator rod, and Fig. 8 is the structural representation of another modulator rod, modulator
Rod 2 is made up of FM1 layers 21, NM layers 22 and the three-decker of FM2 layers 23, and wherein FM1 layers and FM2 layers is soft ferromagnetic layer, NM layers
Ordinary metal layer, the structure of described modulator rod 2 is rectangular strip, its major axis parallel to Y direction, its short axle parallel to
X-direction, multiple described modulator rods 2 are set in the form of an array, there is gap, the spacer in the gap between modulator rod
From prolonging X-direction.Arrow 74 and 75 represents flowing in and out for electric current respectively in figure.
Preferably, the material of the NM layers of described modulator rod 2 is ruthenium or copper, and the thickness of the NM layers is less than 5nm, institute
State and antiferromagnetic RKKY couplings between FM1 layers and the FM2 layers be present.
Fig. 7 and Fig. 8 difference is：Preferably, described electric connector 4 is metal conductor element to electric connector in Fig. 7,
It is connected with upper surface, lower surface or the side surface of described modulator rod 2, and the electric connector 4 in Fig. 8 is from FM1 layers, NM
Etched in layer and FM2 layer three-deckers.
Because metal level than FM1 layer and FM2 layers has higher electric conductivity, so, the current collection in modulator rod exists
The intermediate layer of modulator rod；When electric current is very big, FM1 layers and FM2 layers reduce modulator and sensed parallel to sensor element
Magnetic conductivity on direction.Wherein, high magnetic conductivity means the magnetic flux content height concentrated on sensor string, on the contrary, low
Magnetic conductivity means that the magnetic flux content of the concentration on sensor string is low.Therefore, modulator, outside magnetic are passed through by alternating current
Field can be modulated by the change of magnetic conductivity.
The FM1 layers and FM2 layers of modulator need identical remanent magnetism thickness product (Mrt), and so they can be between modulator
Mutually compensated for, however, because the bottom FM2 layers of modulator rod are close to magneto-resistor sensing element, therefore, the FM1 of top layer
The remanent magnetism thickness product of layer is higher than the FM2 layers of bottom.Also, it is electrically connected to each other between modulator stick end, modulates electric current
Modulator rod can be flowed through in a manner of snakelike, can be made up due to FM1 and FM2 not in whole magneto-resistor sensing element region
Matching and caused by it is uneven.
Fig. 9 is the Distribution of Magnetic Field schematic diagram of the modulator rod without modulation electric current, and magnetic field concentration is in magnetic caused by modulator rod
At resistance sensing element.Figure 10 is the Distribution of Magnetic Field schematic diagram for the modulator rod for having modulation electric current, it can be seen that being adjusted when applying
During electric current processed, there is no the concentration in magnetic field in magneto-resistor sensing element.
Another structural representation of the modulator of Figure 11 premodulated magnetic resistance sensors of the present utility model, such as Figure 11 institutes
Show, the modulator of described premodulated magnetic resistance sensor includes current-carrying coil 11 and ferromagnetism cuboid 18, described current-carrying
Coil 11 is located at the top of ferromagnetism cuboid 18, and described current-carrying coil 11 is connected with described bonding welding pad 12.
Figure 12 is the magnetic conductivity of sensor axis with the schematic diagram of modulation curent change；With the increase of modulation electric current, magnetic passes
The magnetic conductivity of sensor axle reduces, and applies AC modulated current, and Figure 13 is the oscillogram of the modulation electric current applied, as can be seen from Figure 13
In, application electric current is sinusoidal signal；The size of magnetic conductivity therein is with electric current just on the contrary, as shown in figure 14, Figure 14 is magnetic conductance
The oscillogram of rate change；Because field gain changes with the change of magnetic conductivity, and then sensor gain oscillogram is obtained, such as schemed
Shown in 15.
Figure 16 is the input and output schematic diagram of modulation magnetic resistance sensor, and it is defeated that modulation magnetic resistance sensor includes modulation electric current
Enter end, modulate current output terminal, sensor current input and sensor current output end, the direction of arrow in figure is pinning layer
Direction.
The utility model also includes exchange reference power supply, and described exchange reference power supply periodically drives institute with frequency f
Modulator rod, analog front circuit, low pass filter and the frequency mixer of sensor are stated, before described analog front circuit includes
End processor and amplifier, described FEP couple with the output capacitor of magnetic resistance sensor, described frequency mixer
Input be electrically connected to described exchange reference power supply and described FEP output end；Described low pass filter
The output end of the described frequency mixer of input electrical connection, the output end of described low pass filter provide an output signal, institute
The output signal stated is corresponding with the amplitude and polarity in magnetic field that described magneto-resistor sensing element is detected.
Figure 17 is unipolar first harmonic application schematic diagram of single magnetoelectricity resistance circuit, and Figure 18 is single magneto-resistor electricity
The ambipolar second harmonic application schematic diagram on road, Figure 19 are unipolar first harmonic application schematic diagram of half-bridge circuit, are schemed
20 be the ambipolar second harmonic application schematic diagram of half-bridge circuit；Figure 21 is unipolar first harmonic application of full-bridge circuit
Schematic diagram；Figure 22 is the ambipolar second harmonic application schematic diagram of full-bridge circuit.
Exchange reference power supply signal described in Figure 17 is unipolar.Described low pass filter and described frequency mixer
Output end connection, described low pass filter be first harmonic low pass filter, have frequency for F low-frequency cut-off frequency.
Also include an Optimal Filter in Figure 17, with described exchange reference power supply or described frequency mixer one
Individual input signal electrical connection, the Optimal Filter pass through the removal portion before exchange reference power supply signal enters mixting circuit
Crossover rate component, and reference power supply signal is exchanged by way of ac voltage signal to adjust the reference power supply changing
Signal.
In Figure 18, described exchange reference power supply signal is that ambipolar, described magnetic resistance sensor also includes frequency multiplication
Device, described frequency multiplier electrically connect with the described input for exchanging reference power supply and described frequency mixer, low pass filter
It is connected with the output end of described frequency mixer, described low pass filter is second harmonic low pass filter, and it is 2F to have frequency
Low-frequency cut-off frequency.
Figure 19 and Figure 20 is respectively adopted two magneto-resistor circuit elements and forms half-bridge circuit.Figure 21 and Figure 22 are respectively adopted
Four magneto-resistor circuit elements form full-bridge circuit, and concrete operating principle is similar to the above.Described sensor bridge includes two
The chip of individual or two or more interconnection, each independent chip include magneto-resistor sensing element string, the sensing of described magneto-resistor
Element string, which is electrically connected, is connected into the bridge arm of one or more sensor bridge circuits；Or the sensor bridge includes one chip,
The bridge arm for forming sensor bridge is deposited on the one chip.
It should be noted that described FM1 layers and described FM2 layers have different remanent magnetism thickness product Mrt；Wherein, in nothing
During externally-applied magnetic field, even if exchange reference power supply signal is maximum, now the modulation electric current is in magnetic field caused by sensing station
For minimum, the modulation electric current is not influenceed in magnetic field caused by sensing station by exchange reference power supply.
It should be noted that when the exchange reference power supply signal is located at operating frequency range, described magneto-resistor passes
Sensor component produces white noise acoustic frequency and is much larger than 1/f noise frequency.Wherein, by increasing the size of sensor, face is expanded
Product can reduce 1/f noise.
The utility model uses the FM stacks of RKKY couplings, and the modulation electric current exported by modulator changes the magnetic
The magnetic conductivity of electric resistance sensor, and therefore modulate magnetic field.Also, the utility model can be in the advance detected by sensor element
Row modulation, it is ensured that modulated signal is located in the corresponding linear regional extent of the magnetic resistance sensor.
Above example only illustrates the technical solution of the utility model, rather than its limitations；Although with reference to the foregoing embodiments
The utility model is described in detail, it will be understood by those within the art that：It still can be to foregoing each
Technical scheme described in embodiment is modified, or carries out equivalent substitution to which part technical characteristic；And these are changed
Or replace, the essence of appropriate technical solution is departed from the spirit and scope of various embodiments of the utility model technical scheme.
Claims (12)
- A kind of 1. premodulated magnetic resistance sensor, it is characterised in that：A substrate, magneto-resistor sensing element, modulator, electric connector, electric insulation layer and bonding welding pad are provided with X/Y plane Deposit over the substrate, the sensing of the magneto-resistor sensing element is oriented parallel to X-axis；The magneto-resistor sensing element is serially connected in magneto-resistor sensing element string, the electrical connection of described magneto-resistor sensing element string Into sensor bridge, the sensor bridge is push-pull type half-bridge circuit or push-pull type full-bridge circuit；Described magnetoelectricity resistance sense Element string is answered to be electrically connected with described bonding welding pad so that bias voltage or electric current flow through described magneto-resistor sensing element simultaneously Detect the voltage or electric current on the magneto-resistor sensing element；The modulator electrically connects with described bonding welding pad, obtains modulating electric current, the modulation electric current from the bonding welding pad The direction for being oriented parallel to Y-axis, the modulator to modulate electric current by the conductor around soft iron magnetic flux concentrator, Magnetic field is produced around soft iron magnetic flux concentrator to modulate the magnetic conductivity of soft iron magnetic flux concentrator, the modulator and magneto-resistor It is provided with one layer of electric insulation layer between sensing element, described electric insulation layer is by the modulator and the magneto-resistor sensing element Separate.
- A kind of 2. premodulated magnetic resistance sensor according to claim 1, it is characterised in that：Described magneto-resistor sensing element is AMR, GMR or TMR magnetic induction part；Described modulator is by multiple modulator rods Form, the structure of described modulator rod is rectangular strip, its major axis parallel to Y direction, its short axle parallel to X-direction, Multiple described modulator rods are set in the form of an array, there is gap between the modulator rod, the spacing distance in the gap X-direction is prolonged in direction, connects into the current path of snakelike shape between the end of described modulator rod by electric connector.
- A kind of 3. premodulated magnetic resistance sensor according to claim 2, it is characterised in that：Described modulator rod be by FM1 layers, NM layers and FM2 layers three-decker are formed, and wherein FM1 layers and FM2 layers are soft ferromagnetic layers, and NM layers are ordinary metal layers；The material of the NM layers is ruthenium or copper, and the thickness of the NM layers is less than 5nm, existed between the FM1 layers and the FM2 layers RKKY couplings.
- A kind of 4. premodulated magnetic resistance sensor according to claim 3, it is characterised in that：The electric connector is gold Category, described electric connector are connected with the upper surface, lower surface or side surface of described modulator；Or the electric connector etches from the three-decker of FM1 layers, NM layers and FM2 layers.
- A kind of 5. premodulated magnetic resistance sensor according to claim 1, it is characterised in that：The modulator includes current-carrying Coil and ferromagnetism cuboid, described current-carrying coil are located at the top of ferromagnetism cuboid, the current-carrying coil with it is described Bonding welding pad connects.
- A kind of 6. premodulated magnetic resistance sensor according to claim 3, it is characterised in that：Described sensor also includes Reference power supply is exchanged, described exchange reference power supply periodically drives modulator rod, mould in described sensor with frequency f Intend front-end circuit, low pass filter and frequency mixer, the analog front circuit includes FEP and amplifier, described FEP couples with the output capacitor of magnetic resistance sensor,The input of described frequency mixer is electrically connected to described exchange reference power supply and described FEP output end,The output end of frequency mixer described in the input electrical connection of described low pass filter, the output of described low pass filter End provides an output signal, the amplitude in the magnetic field that described output signal is detected with described magneto-resistor sensing element and pole Property is corresponding.
- A kind of 7. premodulated magnetic resistance sensor according to claim 6, it is characterised in that：Also include optimization filtering Device, the Optimal Filter electrically connect with exchanging an input signal of reference power supply signal and described frequency mixer,The Optimal Filter by exchange reference power supply signal enter mixting circuit before remove component frequency component, with And reference power supply signal is exchanged by way of ac voltage signal to adjust the reference power supply signal changing.
- A kind of 8. premodulated magnetic resistance sensor according to claim 6, it is characterised in that：Described exchange reference power supply Signal is that unipolar, described low pass filter is connected with the output end of described frequency mixer, described LPF utensil There is the low-frequency cut-off frequency that frequency is F.
- A kind of 9. premodulated magnetic resistance sensor according to claim 7, it is characterised in that：Described exchange reference power supply Signal is that ambipolar, described magnetic resistance sensor also includes frequency multiplier, and described frequency multiplier exchanges benchmark electricity with described The input of source and described frequency mixer is electrically connected, and described low pass filter is connected with the output end of described frequency mixer, Described low pass filter has the low-frequency cut-off frequency that frequency is 2F.
- A kind of 10. premodulated magnetic resistance sensor according to claim 1, it is characterised in that：The sensor bridge bag One chip is included, the bridge arm for forming sensor bridge is deposited on the one chip；Or the sensor bridge includes the chip of two or more interconnection, each independent chip includes magnetoelectricity Sensing element string is hindered, described magneto-resistor sensing element string, which is electrically connected, is connected into the bridge arm of one or more sensor bridges.
- A kind of 11. premodulated magnetic resistance sensor according to claim 7, it is characterised in that：In the exchange benchmark electricity When source signal is located at operating frequency range, described magnetic and electric resistance sensor part produces white noise acoustic frequency much larger than 1/f noise frequency Rate.
- A kind of 12. premodulated magnetic resistance sensor according to claim 6, it is characterised in that：Described FM1 layers and described FM2 layers have different remanent magnetism thickness product Mrt, when without externally-applied magnetic field, even if exchange reference power supply signal is maximum, the modulation Electric current is also minimum in magnetic field caused by sensing station.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107037382A (en) * | 2017-04-05 | 2017-08-11 | 江苏多维科技有限公司 | A kind of premodulated magnetic resistance sensor |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107037382A (en) * | 2017-04-05 | 2017-08-11 | 江苏多维科技有限公司 | A kind of premodulated magnetic resistance sensor |
| WO2018184565A1 (en) * | 2017-04-05 | 2018-10-11 | 江苏多维科技有限公司 | Premodulated magnetoresistive sensor |
| US11287491B2 (en) | 2017-04-05 | 2022-03-29 | MultiDimension Technology Co., Ltd. | Modulated magnetoresistive sensor |
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