CN202372636U - Magnetic field sensing device - Google Patents
Magnetic field sensing device Download PDFInfo
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- CN202372636U CN202372636U CN 201120444666 CN201120444666U CN202372636U CN 202372636 U CN202372636 U CN 202372636U CN 201120444666 CN201120444666 CN 201120444666 CN 201120444666 U CN201120444666 U CN 201120444666U CN 202372636 U CN202372636 U CN 202372636U
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Abstract
The utility model discloses a magnetic field sensing device, which comprises a magnetoresistance sensing element and a coil positioned in the vicinity of the magnetoresistance sensing element. The coercive force and biased field of the magnetoresistance sensing element are the same in magnitude. The coil generates a magnetic field which is parallel to a sensitive axis of the magnetoresistance sensing element; when first current passes through the coil, resetting operation over the magnetoresistance sensing element is realized; and when second current passes through the coil, calibration operation over the magnetoresistance sensing element is realized. The coil is used for calibrating the output curve temperature characteristics of the magnetoresistance sensing element and resetting the magnetization of the magnetoresistance sensing element so as to eliminate hysteresis, and also can be used for self-checking operation. Due to the arrangement of the single coil, the number of soldering- pads on a chip can be decreased, the density of magnetoresistance elements on the chip can be increased, and the size of the chip can be reduced.
Description
Technical field
The present invention relates to a kind of magnetic field sensing device.
Background technology
Magnetic sensor is widely used in modern system and includes but not limited to physical parameters such as magnetic field intensity, electric current, position, motion, direction with measurement.Have many sensors of various types to be used to measure magnetic field, but these sensors all have its defective, for example size is big before, and sensitivity is low, narrow dynamic range, and cost is high, and stability is low etc.
Therefore, improve Magnetic Sensor constantly, particularly improve the sensor and the manufacturing approach thereof that are prone to integrate and be necessary with semiconductor devices or integrated circuit.
Advantages such as tunnel junction magneto-resistor (MTJ, Magnetic Tunnel Junction) sensor has high sensitivity, and size is little, and cost is low and low in energy consumption.Although mtj sensor is compatible mutually with semiconductor standard manufacture technology and it has the performance of high magneto-resistor, the method for preparing high performance MTJ linear magnetic field sensor is not also fully developed.Particularly the problem of temperature characterisitic and magnetic hysteresis is not easy to be controlled effectively.
Magnetic field sensor is made up of single magnetoresistive element, in practical application, generally magnetoresistive element is connected into Wheatstone bridge to eliminate skew, increases sensitivity and temperature characterisitic is done certain compensation.Although bridge configuration can be made certain compensation to temperature characterisitic, the intrinsic magnetic property of sensor magneto-resistor can not suppressed the dependence of temperature fully.For high-acruracy survey, calibration sensitivity is desirable down in working order, and the alignment coil of chip level can reach this purpose along magnetic field of sensor sensing direction generation.When magnetic resistance sensor was in running order, alignment coil can provide the current impulse of a regular short arc, meanwhile, thereby produce pulsed magnetic field around the coil sensitivity of magnetometer was calibrated.
Because magnetic resistance sensor is to be made up of ferromagnetic sensitive element, so curve of output mainly is non-linear, the generation of magnetic hysteresis is the generation and the motion of the domain wall of (for example magnetic masking layer or gather magnetosphere) because sensing element and other parts.In order to overcome above problem, high performance magnetic resistance sensor needs another coil usually, and this coil is with respect to the alignment coil quadrature, and wherein alignment coil is regular saturation field to be provided and to eliminate magnetic domain for sensing element.We preset it called after/resetting coil for the former.
Be provided with preset/reset and alignment coil has increased the operation that sensor is made; Simultaneously sensor chip need increase more pad and bigger encapsulation volume to adapt to preset/reset field and calibration field of quadrature; Thereby the size that makes sensor becomes big, the complicacy that has finally caused sensor to be made.
The magnetic resistance sensor that alignment coil is not set can be realized.The shortcoming of this method is can't be through the sensitivity of electronically survey sensor.That is to say,, just can not monitor and analyze the sensitivity of its curve of output if magnetic resistance sensor is not provided with alignment coil.In addition, the self-checking system of implementation criteria is very loaded down with trivial details in sensor.Therefore in the application of solid-state compass, need one or two loop construction usually.Loop construction is set when increasing size, has also increased power consumption.
The magnetic field intensity that the electric current line produces and its distance are inversely proportional to.Energy-optimised indicating: the distance of the alignment coil of sensor and through current direction and the distance of sensor and resetting coil are enough little.Under the desirable situation, two coils are proximity transducer as far as possible, but is being practically impossible.
Summary of the invention
The invention provides the magnetic field sensing device, this magnetic field sensing device adopt a kind of simple coil design provide preset/reset and calibration function, simultaneously can minification reduce power consumption.Sensor involved in the present invention uses MTJ element or giant magnetoresistance (GMR) element to be sensitive element, on one chip, is integrated with preset/resetting coil and alignment coil simultaneously.This magnetometer adopts a low one pole or bipolar pulse current cycle to carry out calibration operation, adopts a high bipolar pulse to preset/reset operation.
The present invention provides a kind of magnetic field sensing device; It comprises the magneto-resistor sensing element, is positioned near the coil of magneto-resistor sensing element; The coercive force of said magneto-resistor sensing element and biased field big or small identical; Said coil generation one is parallel to the magnetic field of the sensitive axes of said magneto-resistor sensing element, when said coil leads to first electric current, realizes the reset operation of magneto-resistor sensing element; When said coil leads to second electric current, realize the calibration operation of magneto-resistor sensing element.
Preferably, first electric current is greater than second electric current.
Preferably, the scope of said first electric current and second size of current is that 1mA is to 10mA.
Preferably, said coil is single conductive layer.
Preferably, said conductive layer is meander-shaped.
Preferably, said conductive layer shape in the shape of a spiral.
Preferably, this magnetic field sensing device can be used as solid-state compass.
Another kind of magnetic field sensing device; It comprises the magneto-resistor sensing element, is positioned near the coil of magnetoresistive element; The coercive force of said magneto-resistor sensing element and biased field big or small identical; Said coil produces a magnetic field, and this magnetic field has first magnetic-field component that is parallel to magneto-resistor sensing element sensitive axes and perpendicular to second magnetic-field component of magneto-resistor sensing element sensitive axes, first magnetic-field component is greater than second magnetic-field component; Said first magnetic-field component is used for said magneto-resistor sensing element is resetted and calibration operation; Said second magnetic-field component is used to make the edge magnetic domain direction alignment of magneto-resistor sensing element, when said coil leads to first electric current, realizes the reset operation of magneto-resistor sensing element; When said coil leads to second electric current, realize the calibration operation of magneto-resistor sensing element.
Preferably, first electric current is greater than second electric current.
Preferably, the scope of said first electric current and second size of current is that 1mA is to 10mA.
Preferably, the angle between the major axis of the axis of said coil and magneto-resistor sensing element is less than or equal to 22.5 °.
Preferably, described coil is single conductive layer.
Preferably, said conductive layer is a meander-shaped.
Preferably, said conductive layer is spiral-shaped.
Preferably, this magnetic field sensing device can be used as solid-state compass.
Description of drawings
Fig. 1 is the design concept figure of sensing element and coil.
Fig. 2 is the definition figure of the performance index of Magnetic Sensor.
Fig. 3 is the work synoptic diagram that resets.
Fig. 4 is the synoptic diagram of calibration operation.
Fig. 5 is the edge magnetic domain synoptic diagram of the magnetoresistive element of inclination.
Fig. 6 is the edge magnetic domain synoptic diagram of the magnetoresistive element of non-inclination.
Fig. 7 is the geometric configuration synoptic diagram of tortuous coil, this coil the size that can reduce the magneto-resistor chip is set.
Fig. 8 is the geometric configuration synoptic diagram of helical coil.
Embodiment
The present invention relates to a kind of high precision that has, low cost, the magnetic resistance sensor of low-power consumption.The sensor of this low-power consumption is applied to mancarried electronic aids such as mobile phone, wrist-watch, laptop computer and touch flat-panel devices especially.Particularly this magnetic resistance sensor can be used for making navigation usefulness solid-state compass so that the reference direction in magnetic field of the earth to be provided.
Fig. 1 is the design concept figure of sensing element and coil.As shown in the figure, magneto-resistor sensing element 10 is positioned at the top or the below of conductor 11, electric current 12 conductor of flowing through.Magnetic field B (I) 13 that electric current 12 produces is perpendicular to direction of current.Sensing element 10 can select to be provided with an angle 14 with conductor 11, so the sensitive direction 15 of magnetic field 13 and sensor is not vertical.
Fig. 2 has described the curve of output 20 of magnetic resistance sensor, and curve of output 20 has defined coercive force (H
c) 21 and biased field (H
Offset) parameters such as 22.Curve of output 20 is sensor output voltage 23 functions about outfield 24.Under the ideal situation, the curve of output 20 of sensor is from putting 25s.The curve of output of the area sensor of point more than 26 that saturation field is corresponding is near linear.But this is a model of too simplifying, and the output meeting of sensor is squinted along with the rising of temperature, and its magnetic hysteresis can increase along with the change of magnetic domain.
Sensor can be worked under the pattern of low magnetic hysteresis and low skew and observed:
H
c?=?H
offset, （1）
Sensor along on the direction of sensitive direction 15 by regularly saturated, therefore order about the position of point 27 of magnetized state to the curve of output of sensor.
A simple initialization procedure as shown in Figure 3 can be explained this effect.Reset field H
Reset(30) be used to make sensor to get into state of saturation and greater than the zone of curve of output point 27.Reset field H
Reset(30) after the elimination, the sensor curve of output turns back on the working point 25 through path 31-32.This simple unipolar pulse reseting procedure possibly be the coercitive mode of the most effectively removing; If adopt bipolar pulse or adopt the unipolar pulse clapped one more maybe effect can be better, provide a magnetic field to make magnetic resistance sensor be positioned at regional more than magnetic field 30 or 30 and reach capacity in the last pulse of continuous impulse.
After initialization, the magnetic field sensing device can be calibrated or self check work according to mode shown in Figure 4.Produce one little of a calibration pulse generation and the little magnetic field H of sensitive direction conllinear through Ampereconductors
Cal(40).This magnetic field can produce a variation in magnetic resistance sensor voltage V41 is responding the variation that aforesaid outfield H (42) causes, so sensitivity just can be decided:
Sensitivity?=?ΔH/ΔV. (2)
Calibration process is to accomplish through the train of impulses that utilizes some CF or shape, therefore can distinguish mutually with background signal.Should regularly or continue to calibrate to eliminate the temperature characterisitic of magneto-resistor sensing element 10.Pulse can be an one pole or bipolar, can be a monopulse, also can be a continuous square wave or sine wave.
Usually be more favourable with magneto-resistor sensing element 10 α (14) that rotates a certain angle, this angle [alpha] (14) is as shown in Figure 1 with respect to coil 11.The reason of doing like this is referring to Fig. 5 and Fig. 6.
Fig. 5 has showed the situation of magneto-resistor sensing element 10 with respect to coil 11 rotational angle α (14).In this is provided with, H
Reset(30) a component H who is parallel to the edge of magneto-resistor sensing element 10 is arranged
Edge(51).Because H
Edge(51) enough big, edge magnetic domain 51 is pointed to same direction, the original state that provides a good quilt to define for the magnetic moment of magneto-resistor magneto-resistor sensing element 10.When coil leads to first electric current, realize the reset operation of magneto-resistor sensing element; When coil leads to second electric current, realize the calibration operation of magneto-resistor sensing element.First electric current is greater than second electric current, and the scope of first electric current and second electric current all arrives 10mA at 1mA.
Fig. 6 has showed possibly arranging of edge magnetic domain when magneto-resistor sensing element 10 and coil 11 are arranged in parallel, and such setting can not produce the reset field component H that is parallel to the sensor edge
EdgeIn this case, do not have external force to make the direction of magnetic domains point edge magnetic domain 51, and possibly produce direction opposed edges magnetic domain 61 on the edge of.This is a stochastic process, makes the behavior of sensor unpredictable, and the domain motion that magnetic moment is relative can produce magnetic hysteresis when reset operation.When coil leads to first electric current, realize the reset operation of magneto-resistor sensing element; When coil leads to second electric current, realize the calibration operation of magneto-resistor sensing element.First electric current is greater than second electric current, and the scope of first electric current and second electric current all arrives 10mA at 1mA.
Calibration field can be represented by relative angle as follows:
H
true?≈?H
calCos(α) (3)
Precision up to 90%, angle can be provided when being 22.5 °.Can be adjusted into bigger angle if necessary, but because H
EdgeTherefore the reason sensitivity meeting that component increases reduces.In addition, if sensor uses the mode of deposition magnetic layer on permanent magnet integrated on the chip or the element to setover H
EdgeComponent can not produce significant impact to the calibration behavior in calibration process.
Fig. 8 is the conventional in layout method that coil is set.Fig. 7 be other a kind of layout that coil is set as.As shown in the figure, coil 71 is tortuous shape and structures, operation between magneto-resistor sensing element 10.This layout allows the magneto-resistor sensing element more closely to encapsulate than conventional helical layout (as shown in Figure 8).A potential problem of meander configuration coil is a high resistance.The resistance of meander configuration coil is:
(5)
(6)
The magnetic field that the meander configuration coil that above or below element, moves produces is:
" W " refers to the width of conductor in the formula, and " t " refers to the thickness of conductor, and " y " refers to the height apart from conductive surface, and " x " refers to the position of sensitive axes apart from the conductor center.
To note simultaneously:
I
reset?<?V
max/R（L,W1,W2,W3,t,ρ） (8)
Fig. 7 has defined relevant geometric parameter.Wherein, " ρ " is the resistivity of coil method, " V
Max" be the maximum voltage that the magnetometer system can provide.
Design must be weighed assurance has enough H
ResetCan make the magnetometer system use maximum voltage V
MaxBe implemented to high relatively voltage although can on chip, design switching capacity, voltage preferably remains in 5V or the littler scope.Voltage and coil resistance have limited the design of magneto-resistor magneto-resistor sensing element 10 and magnetometer, and they provide a upper limit can realize H
ResetMake the size of resetting coil reach minimum simultaneously.
More than combine diagram to be illustrated to specific embodiment of the present invention, clearly, on the basis of not leaving scope of the present invention and spirit, can much revise prior art and technology.In the technical field, the common knowledge of a GPRS just can be carried out diversified change in technological main idea scope of the present invention under of the present invention.
Claims (15)
1. magnetic field sensing device; It is characterized in that: it comprises the magneto-resistor sensing element, is positioned near the coil of magneto-resistor sensing element; The coercive force of said magneto-resistor sensing element and biased field big or small identical; Said coil generation one is parallel to the magnetic field of the sensitive axes of said magneto-resistor sensing element, when said coil leads to first electric current, realizes the reset operation of magneto-resistor sensing element; When said coil leads to second electric current, realize the calibration operation of magneto-resistor sensing element.
2. magnetic field sensing device according to claim 1 is characterized in that: said first electric current is greater than second electric current.
3. magnetic field sensing device according to claim 1 is characterized in that: the scope of said first electric current and second size of current is that 1mA is to 10mA.
4. according to the described magnetic field sensing device of one of claim 1-3, it is characterized in that: said coil is single conductive layer.
5. magnetic field sensing device according to claim 4 is characterized in that: said conductive layer is meander-shaped.
6. magnetic field sensing device according to claim 4 is characterized in that: said conductive layer is shape in the shape of a spiral.
7. magnetic field sensing device according to claim 1 is characterized in that: this magnetic field sensing device can be used as solid-state compass.
8. another kind of magnetic field sensing device; It is characterized in that: it comprises the magneto-resistor sensing element, is positioned near the coil of magnetoresistive element; The coercive force of said magneto-resistor sensing element and biased field big or small identical; Said coil produces a magnetic field, and this magnetic field has first magnetic-field component that is parallel to magneto-resistor sensing element sensitive axes and perpendicular to second magnetic-field component of magneto-resistor sensing element sensitive axes, first magnetic-field component is greater than second magnetic-field component; Said first magnetic-field component is used for said magneto-resistor sensing element is resetted and calibration operation; Said second magnetic-field component is used to make the edge magnetic domain direction alignment of magneto-resistor sensing element, when said coil leads to first electric current, realizes the reset operation of magneto-resistor sensing element; When said coil leads to second electric current, realize the calibration operation of magneto-resistor sensing element.
9. magnetic field sensing device according to claim 8 is characterized in that: said first electric current is greater than second electric current.
10. magnetic field sensing device according to claim 8 is characterized in that: the scope of said first electric current and second size of current is that 1mA is to 10mA.
11. magnetic field sensing device according to claim 8 is characterized in that: the angle between the major axis of the axis of said coil and magneto-resistor sensing element is less than or equal to 22.5 °.
12. described magnetic field sensing device one of according to Claim 8-11, it is characterized in that: described coil is single conductive layer.
13. magnetic field sensing device according to claim 12 is characterized in that: said conductive layer is a meander-shaped.
14. magnetic field sensing device according to claim 12 is characterized in that: said conductive layer is spiral-shaped.
15. magnetic field sensing device according to claim 8 is characterized in that: this magnetic field sensing device can be used as solid-state compass.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120444666 CN202372636U (en) | 2011-11-11 | 2011-11-11 | Magnetic field sensing device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120444666 CN202372636U (en) | 2011-11-11 | 2011-11-11 | Magnetic field sensing device |
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| CN202372636U true CN202372636U (en) | 2012-08-08 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102540113A (en) * | 2011-11-11 | 2012-07-04 | 江苏多维科技有限公司 | Magnetic field sensing device |
| CN113495233A (en) * | 2020-03-18 | 2021-10-12 | Tdk株式会社 | Magnetic field detection device and current detection device |
-
2011
- 2011-11-11 CN CN 201120444666 patent/CN202372636U/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102540113A (en) * | 2011-11-11 | 2012-07-04 | 江苏多维科技有限公司 | Magnetic field sensing device |
| WO2013067865A1 (en) * | 2011-11-11 | 2013-05-16 | 江苏多维科技有限公司 | Magnetic field sensing device |
| JP2014532883A (en) * | 2011-11-11 | 2014-12-08 | 江▲蘇▼多▲維▼科技有限公司Ｊｉａｎｇ Ｓｕ Ｍｕｌｔｉ Ｄｉｍｅｎｓｉｏｎ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏ．，Ｌｔｄ | Magnetometer with dual purpose reset and calibration coil |
| US9599693B2 (en) | 2011-11-11 | 2017-03-21 | MultiDimension Technology Co., Ltd. | Magnetometer with dual purpose reset and calibration coil |
| CN113495233A (en) * | 2020-03-18 | 2021-10-12 | Tdk株式会社 | Magnetic field detection device and current detection device |
| CN113495233B (en) * | 2020-03-18 | 2024-04-05 | Tdk株式会社 | Magnetic field detection device and current detection device |
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Granted publication date: 20120808 |
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