(19)
(11)EP 2 790 030 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
20.11.2019 Bulletin 2019/47

(21)Application number: 12847626.4

(22)Date of filing:  26.09.2012
(51)International Patent Classification (IPC): 
G01R 33/09(2006.01)
G01R 35/00(2006.01)
G01R 33/00(2006.01)
(86)International application number:
PCT/CN2012/082015
(87)International publication number:
WO 2013/067865 (16.05.2013 Gazette  2013/20)

(54)

MAGNETIC FIELD SENSING DEVICE

MAGNETFELDSENSOR

DISPOSITIF DE DÉTECTION DE CHAMP MAGNÉTIQUE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 11.11.2011 CN 201110356226

(43)Date of publication of application:
15.10.2014 Bulletin 2014/42

(73)Proprietor: Multidimension Technology Co., Ltd.
Free Trade Zone Zhangjiagang, Jiangsu 215634 (CN)

(72)Inventors:
  • DEAK, James G.
    Zhangjiagang Jiangsu 215600 (CN)
  • SHEN, Weifeng
    Zhangjiagang Jiangsu 215600 (CN)
  • LEI, Xiaofeng
    Zhangjiagang Jiangsu 215600 (CN)
  • XUE, Songsheng
    Zhangjiagang Jiangsu 215600 (CN)

(74)Representative: HGF Limited 
4th Floor Merchant Exchange 17-19 Whitworth Street West
Manchester M1 5WG
Manchester M1 5WG (GB)


(56)References cited: : 
EP-A2- 0 544 479
WO-A1-2010/143718
CN-A- 101 427 157
CN-A- 102 540 113
DE-A1- 19 740 408
FR-A1- 2 876 800
US-A1- 2009 072 815
US-A1- 2010 013 471
US-A1- 2010 026 288
WO-A1-99/09427
CN-A- 101 044 412
CN-A- 101 611 327
CN-U- 202 372 636
DE-A1-102010 028 390
US-A1- 2003 117 254
US-A1- 2009 108 841
US-A1- 2010 026 288
US-A1- 2011 169 488
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of the Invention



    [0001] This invention relates to a magnetic field sensing device.

    Background of the Invention



    [0002] Magnetic sensors are widely used in modern systems to measure or detect physical parameters including but not limited to magnetic field strength, current, position, motion, orientation, and so forth. There are many different types of sensors in the prior art for measuring magnetic field, but these sensors have limitations that are well known in the art, such as, excessive size, inadequate sensitivity and/or dynamic range, cost, reliability and other factors.

    [0003] Hence, there is a need for improved magnetic sensors, especially sensors that can be easily integrated with semiconductor devices and integrated circuits and manufacturing methods thereof.

    [0004] Magnetic tunnel junction (MTJ) sensors have the advantages of high sensitivity, small size, low cost, and low power consumption. Although MTJ devices are compatible with standard semiconductor fabrication processes, methods for building high performance MTJ linear magnetic field sensors have not been adequately developed. In particular, performance issues due to temperature dependence and hysteresis are not easy to control.

    [0005] Magnetic field sensors may be constructed from a single magneto resistive element, but in practice it is advantageous to configure several magnetoresistive elements into a Wheatstone bridge in order to eliminate offset, increase sensitivity, and provide some level of temperature compensation. Although bridge configurations do improve temperature compensation, the inherent temperature dependence of the magnetoresistance and magnetic properties of the sensor are not completely suppressed. For high accuracy, it is desirable to calibrate the sensitivity during operation, and an on-chip calibration coil that produces a known magnetic field along the sensitive direction of the sensor is often provided for this purpose. Calibration is often performed by periodically applying a low amplitude current pulse sequence to the calibration coil, which provides a known magnetic field pulse sequence from which the sensitivity of the magneto resistive sensor may be determined during operation of the magnetometer.

    [0006] Because magnetoresistive sensors are composed of ferromagnetic sensing elements, the sensor response is subject to nonlinearities, offset, and hysteresis due to the formation and motion of domain walls within the sensor elements or other components, such as magnetic shields and flux concentrators. To overcome this issue, high performance magnetoresistive sensors are often provided with another coil, orthogonal to the calibration coil that is used to periodically saturate the sensor elements and sweep out magnetic domains. This is referred to as a set/reset coil.

    [0007] The presence of both the calibration and set/reset coils adds complexity to magnetoresistive sensor fabrication by increasing the number of process steps required to manufacture the sensor, and it increases the size of the sensor die by requiring more contact pads and to accommodate the geometrical constraints required to produce the orthogonal calibration and set/reset fields.

    [0008] Magnetoresistive sensors without a calibration coil are possible. A disadvantage of this approach is the fact that the sensitivity of the sensor cannot be measured by electrical means. That is, if the magnetoresistive sensor does not have a calibration coil, the response of the sensor cannot be monitored and analyzed for sensitivity. Moreover, implementing a standard self-test in the sensor is cumbersome.

    [0009] The magnetic field that is generated by a line current decreases inversely proportionally with the distance from the line. Power optimization indicates that the distance between the sensor and the calibration coil, and the distance between the sensor and the reset coil should be as small as possible. Ideally both coils should be located as close as possible to the sensor. This is however physically impossible.

    [0010] EP0544479A2 discloses a magnetic sensor with elements in a bridge configuration and with a first current-carrying conductor for set/reset and a second one for test, set-up and calibration. US2003/0117254A1 discloses a MR sensor with an offset strap and a set-reset strap. DE10201002839A1 discloses a magnetic field sensor with two exciter conductors for calibration purposes. US2011/0169488A1 discloses a magnetic field sensing device with a calibrating and testing structure comprising a stabilization line and a self-test line. US2010/0013471A1 discloses a MR magnetometer with a single combined flip and compensation coil placed at an angle with respect to the length of the sensor element. US2010/0026288A1 discloses a circuit for resetting a MR element comprising a conductor generating a reset current. US2009/0072815A1 discloses a magnetic sensor device with a MR element, and external coil for calibration and two excitation wires. WO2010/143718A1 discloses a magnetic current sensor with feedback and calibration coils. It subtracts the offset from the measurement result so that the hysteresis error is minimized. FR2876800 discloses a MR sensor providing correction to avoid hysteresis by incorporating an induction coil. US2009/010884A1 discloses a two-axis magnetic field sensor with two first and two second conductors to reset and cancel external offset magnetic field. WO99/09427 discloses a magnetic field sensing device with elements arranged in a bridge with three coil conductors for set-reset, test, compensation, calibration and feedback. DE19740408A1 discloses a magnetic field sensor with several magnetoresistors and a conductor for reversing the magnetisation and/or compensation.

    Summary of the Invention



    [0011] There is provided a magnetic field sensor in accordance with the appended claims. A method for mass production of linear magnetoresistive sensor bridges using a simplified coil design is disclosed. The disclosed sensor uses MTJ or giant magnetoresistive (GMR) elements combined with a single on-chip coil for the calibration and set/reset operations. The magnetometer uses a low unipolar or bipolar current pulse cycle for the calibration operation, and a large unipolar current pulse for the reset operation.

    [0012] The present invention concerns a magnetic field sensor as described in claim 1. Advantageous embodiments are described in the dependent claims. There is disclosed a magnetic field sensing device, including magnetoresistive sensing elements, wherein the coercivity of said sensing elements is equal to the offset field of the sensing elements, a coil placed near said magnetoresistive sensing elements, which generates a magnetic field parallel to the sensing axis of said magnetoresistive elements, and a first current through the coil is used to reset the sensing elements while a second current is used to calibrate the response of the sensing elements.

    [0013] Preferably, said first current through the coil is greater than said second current.

    [0014] Preferably, said first and second currents are in the range of 1 to 10 mA.

    [0015] Preferably, said coil is a single conductive layer.

    [0016] Preferably the coil is a meander shape.

    [0017] Alternatively, the coil is a spiral shape.

    [0018] The sensor may be used as a compass.

    [0019] The magnetic sensor includes a magnetic sensing element that has coercivity equal to its offset field is located close to a coil, and the coil generates a first magnetic field parallel to the sensing axis of the magnetoresistive sensor and a second magnetic field component perpendicular to the sensing axis of the magnetoresistive sensor, wherein the first magnetic field component is greater than the second magnetic field component, said first magnetic field component is used for set/reset and calibration functions and said second magnetic field component is used to properly align domains at the edges of the magnetoresistive sensor elements, and further a first current through the coil is used for the set/reset function, and a second current is used for calibration of the magnetoresistive sensing element.

    [0020] Preferably, said first current through the coil is greater than said second current.

    [0021] Preferably, said first and second currents are in the range of 1 to 10 mA.

    [0022] Preferably, the angle between the current direction and the long axis of the magnetoresistive sensing element is less than or equal to 22.5°.

    [0023] Preferably, said coil is a single conductive layer.

    [0024] Preferably the coil is a meander shape.

    [0025] Alternatively, the coil is a spiral shape.

    [0026] The sensor may be used as a compass.

    Description of the Drawings



    [0027] 

    Figure 1 - Schematic drawing of the configuration of a sensor element and coil.

    Figure 2 - Definition of magnetic sensor performance metrics.

    Figure 3 - Explanation of the reset operation.

    Figure 4. - Explanation of the calibration operation.

    Figure 5 - Edge domains in canted magnetoresistive element.

    Figure 6 - Edge domains in uncanted magnetoresistive element.

    Figure 7 - Schematic drawing of a meander coil geometry that may be used to decrease the size of the magnetometer chip.

    Figure 8 - A schematic drawing of the spiral coil geometry.


    Preferred Embodiments



    [0028] The invention relates to an electronic device with a high accuracy magnetoresistive sensor to be used in low cost and possibly low power applications. Low-power sensors are particularly interesting for mobile electronic devices such as mobile telephones, watches, portable computers, or personal touch screen devices, etc. In particular, magnetoresistive sensors can be used to implement an electronic compass in order to provide a navigational reference with respect to the earth's magnetic field.

    [0029] Figure 1 illustrates the simplified concept of the sensing element and coil geometry. Here, a magnetoresistive sensor element 10 sits atop or beneath a conductor 11, through which a current 12 is sourced. The current 12 produces a magnetic field, B(I) 13 in a direction perpendicular to the current flow. The sensor 10 and conductor 11 may optionally be set at an angle 14 so that the magnetic field 13, is not perpendicular to the sensing direction 15 of the sensor 10.

    [0030] Figure 2 depicts a transfer curve 20 for magnetoresistive sensors in order to define the coercivity (Hc) 21 and offset (Hoffset) 22 parameters. The transfer curve 20 is a measure of sensor output voltage 23 as a function of applied magnetic field 24. Ideally, sensing is performed on the arm of the transfer curve 20 that passes through the origin of the plot 25. Then, provided the sensor is never driven into saturation beyond point 26, the sensor approximates linear response. This is an over simplification, as the sensor will drift with changes in temperature and lower values of field, but provided the sensor is periodically initialized, it can remain on portion 25 of the transfer curve.

    [0031] A sensor can be operated in this low hysteresis mode if the following condition is met:

    and the device is periodically saturated using a field along the sensing direction 15 that drives the transfer curve beyond point 27.

    [0032] A simple initialization procedure is shown in Figure 3. Here, a field value denoted as Hreset 30 is applied to the sensor to cause it to go into saturation at a field greater than that associated with point 27 on the transfer curve. Upon removal of Hreset 30, the sensor follows path 31-32 and returns to operating point 25. This simple reset procedure would likely be the most power efficient means for removing coercivity, but it may produce better results to use a bipolar pulse sequence, or a multi-shot unipolar pulse sequence, provided the last pulse always supplies a field that saturates the magnetoresistive sensor at field 30 or greater than field 30.

    [0033] After initialization, the device may be calibrated or self-tested during operation as illustrated in Figure 4. Here, a small calibration pulse is applied through the current conductor to produce a small field Hcal 40 collinearly with the sensing axis. The field produces a voltage change ΔV in the magnetoresistive sensor 41 in response to the known change in the applied magnetic field ΔH 42, such that the sensitivity may be determined from

    The calibration procedure may be accomplished using a pulse train at some specific frequency or shape such that it is possible to distinguish it from the background signal. The calibration can be performed periodically to remove temperature dependence of the magneto resistive sensor elements. The pulse train can be unipolar or bipolar, it may be a single pulse, or it may be a continuous square wave or sinusoidal tone.

    [0034] It is often advantageous to rotate the sensor element 10 by angle α 14 with respect to the coil 11 as illustrated in Figure 1. The reason for this is illustrated in Figures 5 and 6.

    [0035] Figure 5 shows the case where the sensor element 10 is rotated with respect to the coil 11 by angle α 14. In this configuration, Hreset 30 will have a component Hedge 51 that is parallel to the edge of the sensor element 10. In the presence of sufficiently large Hedge, the edge domains 51 are forced to align in the same direction, providing a well defined initial state for the magnetization of the magnetoresistive sensor 10. When a first current in the coil is applied, a magnetic reset operation can be performed; when the second current in the coil is applied, a calibration operation is performed. The first current is greater than the second current, and the first and second currents are in the range of 1 to 10 mA.

    [0036] Figure 6 illustrates a possible edge domain arrangement for a sensor 10 - conductor 11 arrangement that does not produce a reset field component Hedge 50 parallel to the sensor edge. In this case, there is no driving force to align domains at the edge of the sensor 51, and it is possible for head-to-head domains to form at the edges 61. This is a stochastic process, that makes the device unpredictable, and motion of the domains during operation can produce hysteresis.

    [0037] The calibration may be corrected as follows:

    This provides better than 90% accuracy for angles as large as 22.5 degrees. Larger angles can be adjusted for the decrease in sensitivity resulting from the Hedge 50 component, if needed. Alternatively, if the sensor is biased using on-chip magnets or in-stack biasing, the Hedge component present during calibration may not have any significant influence on the calibration.

    [0038] A preferred layout for the coil is shown in Figure 7. The traditional layout is shown in Figure 8. In the preferred layout, the coil is a meander pattern, with return leads 71 that run between sensor elements 10. This arrangement permits the sensor elements to be more tightly packed than the conventional spiral geometry shown in Figure 8. A potential issue with the meander coil geometry is high resistance. The resistance of the coil is given as:

    If

    Then:

    The field produced by the portion of the meander coil that runs atop or beneath the sensor elements is given by:

    Here, "W" is the width of the conductor, "t" is the thickness of the conductor, "y" is the height above (or below the surface of the conductor), and "x" is a position along the sensing axis from the center of the conductor.

    [0039] Note also,

    Where the geometric parameters are defined in Figure 7, ρ is the conductivity of the coil material, and Vmax is the maximum possible voltage the magnetometer system can deliver.

    [0040] It is apparent that care must be taken such that Hreset can be achieved using a voltage that is less than Vmax. Although it is possible to use a switched capacitor scheme to achieve sufficient voltages, it is preferable to keep the voltages in the range of 5 V or smaller. The voltage constraint and coil resistance places restrictions on magnetoresistive element 10 and magnetometer design. They place an upper bound on the achievable Hreset and limit the size of the reset coil.

    [0041] It will be apparent to those skilled in the art that various modifications can be made to the proposed invention without departing from the scope of the invention, which is defined by the appended claims.


    Claims

    1. A magnetic field sensor, comprising:

    at least one magnetoresistive sensor element (10); and

    an electric conductor (11) in the proximity of the magnetoresistive sensor element (10) in order to generate a magnetic biasing field (13),

    wherein the magnetic field sensor is configured to generate a magnetic biasing field (13) such that the magnetic offset field (22) of the magnetoresistive sensor element (10) is equal to the coercivity (21) of the magnetoresistive sensor element (10), wherein the magnetic field sensor is configured to apply an electric current (12) to the electric conductor (11) to generate a magnetic biasing field or a magnetic biasing field component parallel to a sensing axis (15) of the magnetoresistive sensor element (10), wherein the magnetic field sensor is configured to apply a first electric current to reset the magnetic field sensor, and
    wherein the magnetic field sensor is configured to apply a second electric current to calibrate the magnetic field sensor.
     
    2. A magnetic field sensor as in claim 1, wherein the first electric current is larger than the second electric current.
     
    3. A magnetic field sensor as in claim 1, wherein the first electric current and the second electric current are in the range of 1mA and 10mA.
     
    4. A magnetic field sensor as in claims 1 to 3, wherein the electric conductor (11) is formed from a single conducting layer.
     
    5. A magnetic sensor as in claim 4, wherein the electric conductor (11) is formed into a meander pattern coil, with return leads (71) that run between parallel rows of magnetoresistive sensor elements (10), and field generating leads that sit atop or beneath the magnetoresistive sensor elements (10).
     
    6. A magnetic sensor as in claim 4, wherein the electric conductor (11) is patterned into a spiral coil.
     
    7. A magnetic sensor as in claim 1, wherein the magnetic sensor can be used as a solid-state compass.
     
    8. A magnetic field sensor according to any preceding claim,
    wherein the sensing axis (15) of the magnetoresistive sensor element (10) is angled (14) relative to the electric conductor (11), and the magnetic biasing field (13) has:

    a first magnetic biasing field component parallel to a sensing axis (15) of the magnetoresistive sensor element (10) for reset and calibration; and

    a second magnetic biasing field component perpendicular to the sensing axis (15) of the magnetoresistive sensor element (10) for aligning magnetic domains at edges of the magnetoresistive sensor element (10),

    wherein the first magnetic biasing field component is larger than the second magnetic biasing field component.
     
    9. A magnetic field sensor as in claim 8, wherein an angle (14) of the central axis of the electric conductor (11) with respect with a long axis of the magnetoresistive sensor element (10) is ≤ 22.5°.
     
    10. A magnetic field sensor according to any preceding claim, wherein the magnetoresistive sensor element (10) is configured to be biased using on-chip magnets or in-stack biasing.
     


    Ansprüche

    1. Magnetfeldsensor, umfassend:

    mindestens ein magnetoresistives Sensorelement (10); und

    einen elektrischen Leiter (11) in der Nähe des magnetoresistiven Sensorelements (10) zur Erzeugung eines Vormagnetisierungsfelds (13),

    wobei der Magnetfeldsensor so gestaltet ist, dass er Vormagnetisierungsfeld (13) erzeugt, so dass das magnetische Offset-Feld (22) des magnetoresistiven Sensorelements (10) der Koerzivitätsfeldstärke (21) des magnetoresistiven Sensorelements (10) entspricht,

    wobei der Magnetfeldsensor so gestaltet ist, dass er dem elektrischen Leiter (11) einen elektrischen Strom (12) zuführt, um ein Vormagnetisierungsfeld oder eine Vormagnetisierungsfeldkomponente parallel zu einer Messachse (15) des magnetoresistiven Sensorelements (10) zu erzeugen, wobei der Magnetfeldsensor so gestaltet ist, dass er einen ersten elektrischen Strom zuführt, um den Magnetfeldsensor zurückzusetzen, und

    wobei der Magnetfeldsensor so gestaltet ist, dass er einen zweiten elektrischen Strom zuführt, um den Magnetfeldsensor zu kalibrieren.


     
    2. Magnetfeldsensor nach Anspruch 1, wobei er erste elektrische Strom höher ist als der zweite elektrische Strom.
     
    3. Magnetfeldsensor nach Anspruch 1, wobei er erste elektrische Strom und der zweite elektrische Strom im Bereich von 1mA und 10mA liegen.
     
    4. Magnetfeldsensor nach einem der Ansprüche 1 bis 3, wobei der elektrische Leiter (11) als eine einzelne leitende Schicht ausgebildet ist.
     
    5. Magnetsensor nach Anspruch 4, wobei der elektrische Leiter (11) in eine mäanderförmige Spule ausgebildet ist, mit Rückführungsleitungen (71), die zwischen parallelen Reihen magnetoresistiver Sensorelemente (10) verlaufen, und mit Felderzeugungsleitungen, die über oder unter den magnetoresistiven Sensorelementen (10) angeordnet sind.
     
    6. Magnetsensor nach Anspruch 4, wobei der elektrische Leiter (11) als eine Spiralspule ausgebildet ist.
     
    7. Magnetsensor nach Anspruch 1, wobei der Magnetsensor als Festkörperkompass verwendet werden kann.
     
    8. Magnetfeldsensor nach einem der vorstehenden Ansprüche,
    wobei die Messachse (15) des magnetoresistiven Sensorelements (10) im Verhältnis zu dem elektrischen Leiter (11) angewinkelt (14) ist, und wobei das Vormagnetisierungsfeld (13) folgendes aufweist:

    eine erste Vormagnetisierungsfeldkomponente parallel zu einer Messachse (15) des magnetoresistiven Sensorelements (10) zum Zurücksetzen und zur Kalibrierung; und

    eine zweite Vormagnetisierungsfeldkomponente senkrecht zu der Messachse (15) des magnetoresistiven Sensorelements (10) zur Ausrichtung magnetischer Bereiche an Kanten des magnetoresistiven Sensorelements (10),

    wobei die erste Vormagnetisierungsfeldkomponente größer ist als die zweite Vormagnetisierungsfeldkomponente.
     
    9. Magnetfeldsensor nach Anspruch 8, wobei ein Winkel (14) der zentralen Achse des elektrischen Leiters (11) in Bezug auf eine Längsachse des magnetoresistiven Sensorelements (10) ≤ 22,5° ist.
     
    10. Magnetfeldsensor nach einem der vorstehenden Ansprüche, wobei das magnetoresistive Sensorelement (10) so gestaltet ist, dass es unter Verwendung von auf einem Chip ausgeführten Magneten oder In-Stack-Vormagnetisierung vormagnetisiert wird.
     


    Revendications

    1. Capteur de champ magnétique, comprenant :

    au moins un élément capteur magnétorésistif (10) ; et

    un conducteur électrique (11) à proximité de l'élément capteur magnétorésistif (10) afin de générer un champ de polarisation magnétique (13),

    le capteur de champ magnétique étant conçu pour générer un champ de polarisation magnétique (13) de sorte que le champ de décalage magnétique (22) de l'élément capteur magnétorésistif (10) soit égal à la coercivité (21) de l'élément capteur magnétorésistif (10),

    le capteur de champ magnétique étant conçu pour appliquer un courant électrique (12) au conducteur électrique (11) pour générer un champ de polarisation magnétique ou une composante de champ de polarisation magnétique parallèle à un axe de détection (15) de l'élément capteur magnétorésistif (10), le capteur de champ magnétique étant conçu pour appliquer un premier courant électrique pour réinitialiser le capteur de champ magnétique, et

    le capteur de champ magnétique étant conçu pour appliquer un second courant électrique pour étalonner le capteur de champ magnétique.


     
    2. Capteur de champ magnétique selon la revendication 1, le premier courant électrique étant supérieur au second courant électrique.
     
    3. Capteur de champ magnétique selon la revendication 1, le premier courant électrique et le second courant électrique étant dans la plage comprise entre 1 mA et 10 mA.
     
    4. Capteur de champ magnétique selon les revendications 1 à 3, le conducteur électrique (11) étant formé d'une seule couche conductrice.
     
    5. Capteur magnétique selon la revendication 4, le conducteur électrique (11) étant formé en une bobine à motifs en méandres, avec des fils de retour (71) qui passent entre des rangées parallèles d'éléments capteurs magnétorésistifs (10), et des fils générateurs de champ qui sont situés sur ou sous les éléments capteurs magnétorésistifs (10).
     
    6. Capteur magnétique selon la revendication 4, le conducteur électrique (11) étant structuré en une bobine en spirale.
     
    7. Capteur magnétique selon la revendication 1, le capteur magnétique pouvant être utilisé comme compas électronique.
     
    8. Capteur de champ magnétique selon l'une quelconque des revendications précédentes,
    l'axe de détection (15) de l'élément capteur magnétorésistif (10) étant incliné (14) par rapport au conducteur électrique (11), et le champ de polarisation magnétique (13) ayant :

    une première composante de champ de polarisation magnétique parallèle à un axe de détection (15) de l'élément capteur magnétorésistif (10) pour réinitialisation et étalonnage ; et

    une seconde composante de champ de polarisation magnétique perpendiculaire à l'axe de détection (15) de l'élément capteur magnétorésistif (10) pour aligner des domaines magnétiques aux bords de l'élément capteur magnétorésistif (10),

    la première composante de champ de polarisation magnétique étant plus grande que la seconde composante de champ de polarisation magnétique.
     
    9. Capteur de champ magnétique selon la revendication 8, un angle (14) de l'axe central du conducteur électrique (11) par rapport à un axe long de l'élément capteur magnétorésistif (10) étant ≤ 22,5°.
     
    10. Capteur de champ magnétique selon l'une quelconque des revendications précédentes, l'élément capteur magnétorésistif (10) étant conçu pour être polarisé au moyen d'aimants sur puce ou d'une polarisation en pile.
     




    Drawing


























    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description