WO2011111537A1 - Capteur de courant - Google Patents

Capteur de courant Download PDF

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Publication number
WO2011111537A1
WO2011111537A1 PCT/JP2011/054085 JP2011054085W WO2011111537A1 WO 2011111537 A1 WO2011111537 A1 WO 2011111537A1 JP 2011054085 W JP2011054085 W JP 2011054085W WO 2011111537 A1 WO2011111537 A1 WO 2011111537A1
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WIPO (PCT)
Prior art keywords
magnetic field
magnetic
current sensor
current
film
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PCT/JP2011/054085
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English (en)
Japanese (ja)
Inventor
健司 一戸
正路 斎藤
彰 高橋
洋介 井出
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アルプス・グリーンデバイス株式会社
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Publication of WO2011111537A1 publication Critical patent/WO2011111537A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/205—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using magneto-resistance devices, e.g. field plates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y25/00—Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
    • G01R33/09—Magnetoresistive devices
    • G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors

Definitions

  • the present invention relates to a current sensor using a magnetoresistive effect element (TMR element, GMR element).
  • TMR element magnetoresistive effect element
  • a motor In an electric vehicle, a motor is driven using electricity generated by an engine, and the magnitude of the current for driving the motor is detected by, for example, a current sensor.
  • a current sensor As this current sensor, a magnetic core having a notch (core gap) in part is arranged around a conductor, and a magnetic detection element is arranged in the core gap.
  • a magnetoresistive effect element As a magnetic sensing element of a current sensor, a magnetoresistive effect element (GMR element, TMR) having a laminated structure of a fixed magnetic layer whose magnetization direction is fixed, a nonmagnetic layer, and a free magnetic layer whose magnetization direction varies with respect to an external magnetic field. Element) or the like.
  • a magnetoresistive effect element and a fixed resistance element constitute a full bridge circuit (Patent Document 1).
  • the feedback coil is energized by the voltage difference obtained by the magnetic detection bridge circuit 2, and the induction magnetic field generated by the measured current I energizing the conductor 1 and the cancellation magnetic field generated by the feedback coil cancel each other.
  • the current to be measured is measured based on the current flowing through the feedback coil when the equilibrium state is reached.
  • the magnetic detection bridge circuit 2 of the current sensor shown in FIG. 9 includes one magnetoresistive effect element 201 and three fixed resistance elements 202a to 202c.
  • the resistance value of the magnetoresistive effect element 201 in the zero magnetic field and the resistance values of the fixed resistance elements 202a to 202c are the same (R com ).
  • the output between the fixed resistance elements 202b and 202c is Out1, and the output between the magnetoresistance effect element 201 and the fixed resistance element 202a is Out2.
  • the resistance value of the fixed resistance element 202b is R1
  • the resistance value of the fixed resistance element 202a is R2
  • the resistance value of the fixed resistance element 202c is R3
  • the resistance value of the magnetoresistive effect element 201 is R4.
  • the magnetic detection bridge circuit 2 of the current sensor shown in FIG. 10 includes two magnetoresistive effect elements 201a and 201b and two fixed resistance elements 202a and 202b.
  • the resistance values of the magnetoresistive effect elements 201a and 201b in the zero magnetic field and the resistance values of the fixed resistance elements 202a and 201b are the same (R com ).
  • the resistance change rates of the magnetoresistive effect elements 201a and 201b are the same.
  • the output between the magnetoresistive effect element 201b and the fixed resistance element 202b is set as Out1
  • the output between the magnetoresistive effect element 201a and the fixed resistance element 202a is set as Out2.
  • the resistance value of the magnetoresistive effect element 201b is R1
  • the resistance value of the fixed resistance element 202a is R2
  • the resistance value of the fixed resistance element 202b is R3
  • the resistance value of the magnetoresistive effect element 201a is R4.
  • the present invention has been made in view of the above points, and provides a current sensor capable of performing current measurement with high accuracy by showing a proportional change in the output of the midpoint potential difference with respect to the induced magnetic field generated by the current to be measured.
  • the purpose is to do.
  • the current sensor according to the present invention includes two magnetoresistive elements and resistance elements that change in resistance value when an induction magnetic field is applied from a current to be measured, and outputs between the two magnetoresistive elements and A current sensor having a magnetic field detection bridge circuit having an output between two fixed resistance elements, wherein the two magnetoresistive effect elements have the same rate of change in resistance, and have a first strong resistance through an antiparallel coupling film.
  • a self-pinned ferromagnetic pinned layer formed by antiferromagnetically coupling the magnetic film and the second ferromagnetic film, a nonmagnetic intermediate layer, and a soft magnetic free layer; The magnetization direction of the ferromagnetic pinned layer of the effect element is different from each other by 180 °.
  • the magnetization directions of the self-pinned ferromagnetic pinned layers of the two magnetoresistive effect elements that output the midpoint potential in the magnetic detection bridge circuit are different from each other by 180 °, and thus are generated by the current to be measured.
  • the output of the midpoint potential difference shows a proportional change with respect to the induced magnetic field, and current measurement can be performed with high accuracy.
  • a feedback coil that is disposed in the vicinity of the magnetoresistive effect element and generates a canceling magnetic field that cancels the induced magnetic field, and a magnetic shield that attenuates the induced magnetic field and enhances the canceling magnetic field.
  • the current to be measured is measured based on the measured current.
  • the two magnetoresistive elements have a shape formed by folding a plurality of strip-like long patterns arranged so that their longitudinal directions are parallel to each other, and the induced magnetic field and It is preferable that the cancel magnetic field is applied so as to be along a direction orthogonal to the longitudinal direction.
  • the current to be measured is measured by the magnetic field detection bridge circuit based on outputs of the two magnetoresistive elements proportional to the induced magnetic field.
  • the first ferromagnetic film is made of a CoFe alloy containing 40 atomic% to 80 atomic% of Fe
  • the second ferromagnetic film is made of 0 atomic% to 40 atomic% of Fe. It is preferable to be comprised with the CoFe alloy containing.
  • the magnetic shield is preferably made of a high permeability material selected from the group consisting of an amorphous magnetic material, a permalloy magnetic material, and an iron microcrystalline material.
  • the current sensor according to the present invention includes two magnetoresistive elements and resistance elements that change in resistance value when an induction magnetic field is applied from a current to be measured, and outputs between the two magnetoresistive elements and A magnetic field detection bridge circuit having an output between two fixed resistance elements, the two magnetoresistive effect elements have the same resistance change rate, and the first ferromagnetic film and the first ferromagnetic film through an antiparallel coupling film; A ferromagnetic pinned layer formed by antiferromagnetically coupling the two ferromagnetic films, a nonmagnetic intermediate layer, and a soft magnetic free layer. Since the magnetization directions of the magnetic pinned layers are 180 ° different from each other, the output of the midpoint potential difference shows a proportional change with respect to the induced magnetic field generated by the current to be measured, and current measurement can be performed with high accuracy.
  • (A)-(c) is a figure for demonstrating the manufacturing method of the magnetoresistive effect element in the magnetic balance type current sensor which concerns on embodiment of this invention. It is a figure which shows the magnetic detection bridge circuit in the conventional magnetic balance type current sensor. It is a figure which shows the magnetic detection bridge circuit in the conventional magnetic balance type current sensor.
  • FIGS. 1 and 2 are diagrams showing a magnetic balance type current sensor according to an embodiment of the present invention.
  • the magnetic balance type current sensor shown in FIGS. 1 and 2 is disposed in the vicinity of the conductor 11 through which the measured current I flows.
  • This magnetic balance type current sensor includes a feedback circuit 12 that generates a magnetic field (cancellation magnetic field) that cancels the induced magnetic field caused by the current I to be measured flowing through the conductor 11.
  • the feedback circuit 12 includes a feedback coil 121 wound in a direction to cancel the magnetic field generated by the current I to be measured, two magnetoresistive elements 122a and 122b, and two fixed resistance elements 123a and 123b.
  • the feedback coil 121 is a planar coil.
  • the feedback coil since there is no magnetic core, the feedback coil can be manufactured at low cost. Further, as compared with the case of the toroidal coil, it is possible to prevent the canceling magnetic field generated from the feedback coil from spreading over a wide range and to avoid affecting the peripheral circuits. Furthermore, compared to the toroidal coil, when the current to be measured is an alternating current, the cancellation magnetic field can be easily controlled by the feedback coil, and the current flowing for the control is not so large. About these effects, it becomes so large that a to-be-measured electric current becomes a high frequency by alternating current.
  • the planar coil is preferably provided so that both an induction magnetic field and a cancellation magnetic field are generated in a plane parallel to the plane of the planar coil.
  • the resistance values of the magnetoresistive effect elements 122a and 122b are changed by applying an induction magnetic field from the current I to be measured.
  • the two magnetoresistance effect elements 122a and 122b and the fixed resistance elements 123a and 123b constitute a magnetic field detection bridge circuit.
  • This magnetic field detection bridge circuit has two outputs that generate a voltage difference corresponding to the induced magnetic field generated by the current I to be measured.
  • a power source Vdd is connected to a connection point between the magnetoresistive effect element 122a and the fixed resistance element 123a, and between the magnetoresistive effect element 122b and the fixed resistance element 123b.
  • a ground (GND) is connected to the connection point.
  • one output (Out1) is taken out from the connection point between the fixed resistance elements 123a and 123b
  • the other output (Out2) is outputted from the connection point between the magnetoresistance effect elements 122a and 122b. I'm taking it out.
  • This two outputs are amplified by the amplifier 124 and supplied to the feedback coil 121 as a current (feedback current).
  • This feedback current corresponds to a voltage difference according to the induced magnetic field.
  • a cancellation magnetic field that cancels the induction magnetic field is generated in the feedback coil 121.
  • the current to be measured is measured by the detection unit (detection resistor R) based on the current flowing through the feedback coil 121 when the induced magnetic field and the canceling magnetic field cancel each other.
  • FIG. 3 is a sectional view showing the magnetic balance type current sensor shown in FIG.
  • a feedback coil, a magnetic shield, and a magnetic field detection bridge circuit are formed on the same substrate 21.
  • the feedback coil is arranged between the magnetic shield and the magnetic field detection bridge circuit, and the magnetic shield is arranged on the side close to the current I to be measured. That is, the magnetic shield, the feedback coil, and the magnetoresistive element are arranged in this order from the side close to the conductor 11.
  • the magnetoresistive effect element can be furthest away from the conductor 11, and the induction magnetic field applied to the magnetoresistive effect element from the current I to be measured can be reduced.
  • the magnetic shield can be brought closest to the conductor 11, the attenuation effect of the induced magnetic field can be further enhanced. Therefore, the cancellation magnetic field from the feedback coil can be reduced.
  • a thermal silicon oxide film 22 that is an insulating layer is formed on a substrate 21.
  • An aluminum oxide film 23 is formed on the thermal silicon oxide film 22.
  • the aluminum oxide film 23 can be formed by a method such as sputtering. Further, a silicon substrate or the like is used as the substrate 21.
  • magnetoresistance effect elements 122a and 122b and fixed resistance elements 123a and 123b are formed, and a magnetic field detection bridge circuit is formed.
  • the magnetoresistive elements 122a and 122b TMR elements (tunnel magnetoresistive elements), GMR elements (giant magnetoresistive elements), and the like can be used.
  • the film configuration of the magnetoresistive element used in the magnetic balance type current sensor according to the present invention will be described later.
  • the magnetoresistive effect element has a shape (a meander shape) formed by folding a plurality of strip-like long patterns (stripes) arranged so that their longitudinal directions are parallel to each other.
  • the GMR element is preferably included.
  • the sensitivity axis direction (Pin direction) is a direction (stripe width direction) orthogonal to the longitudinal direction (stripe longitudinal direction) of the long pattern.
  • an induced magnetic field and a cancel magnetic field are applied along a direction (stripe width direction) orthogonal to the stripe longitudinal direction.
  • the width in the pin direction is preferably 1 ⁇ m to 10 ⁇ m.
  • the longitudinal direction is both perpendicular to the direction of the induction magnetic field and the direction of the cancellation magnetic field.
  • an electrode 24 is formed on the aluminum oxide film 23.
  • the electrode 24 can be formed by photolithography and etching after forming an electrode material.
  • a polyimide layer 25 is formed as an insulating layer on the aluminum oxide film 23 on which the magnetoresistive effect elements 122a and 122b, the fixed resistance elements 123a and 123b, and the electrode 24 are formed.
  • the polyimide layer 25 can be formed by applying and curing a polyimide material.
  • a silicon oxide film 27 is formed on the polyimide layer 25.
  • the silicon oxide film 27 can be formed by a method such as sputtering.
  • a feedback coil 121 is formed on the silicon oxide film 27.
  • the feedback coil 121 can be formed by photolithography and etching after the coil material is deposited. Alternatively, the feedback coil 121 can be formed by photolithography and plating after forming a base material.
  • a coil electrode 28 is formed on the silicon oxide film 27 in the vicinity of the feedback coil 121.
  • the coil electrode 28 can be formed by photolithography and etching after forming an electrode material.
  • a polyimide layer 29 is formed as an insulating layer on the silicon oxide film 27 on which the feedback coil 121 and the coil electrode 28 are formed.
  • the polyimide layer 29 can be formed by applying and curing a polyimide material.
  • a magnetic shield 30 is formed on the polyimide layer 29.
  • a high magnetic permeability material such as an amorphous magnetic material, a permalloy magnetic material, or an iron microcrystalline material can be used.
  • a silicon oxide film 31 is formed on the polyimide layer 29.
  • the silicon oxide film 31 can be formed by a method such as sputtering.
  • Contact holes are formed in predetermined regions of the polyimide layer 29 and the silicon oxide film 31 (the region of the coil electrode 28 and the region of the electrode 24), and electrode pads 32 and 26 are formed in the contact holes, respectively. Photolithography and etching are used for forming the contact holes.
  • the electrode pads 32 and 26 can be formed by photolithography and plating after forming an electrode material.
  • the induced magnetic field A generated from the current I to be measured is received by the magnetoresistive element, and the induced magnetic field is fed back from the feedback coil 121.
  • the cancel magnetic field B is generated, and the two magnetic fields (the induction magnetic field A and the cancel magnetic field B) are canceled and adjusted appropriately so that the magnetic field applied to the magnetoresistive effect element 121 becomes zero.
  • the magnetic balanced current sensor of the present invention has a magnetic shield 30 adjacent to the feedback coil 121 as shown in FIG.
  • the magnetic shield 30 attenuates the induced magnetic field generated from the current I to be measured and applied to the magnetoresistive effect element (in the magnetoresistive effect element, the direction of the induced magnetic field A and the direction of the canceling magnetic field B is opposite), and the feedback coil
  • the cancellation magnetic field B from 121 can be enhanced (in the magnetic shield, the direction of the induction magnetic field A and the direction of the cancellation magnetic field B are the same). Therefore, since the magnetic shield 30 functions as a magnetic yoke, the current flowing through the feedback coil 121 can be reduced, and power saving can be achieved. Further, the magnetic shield 30 can reduce the influence of an external magnetic field.
  • the magnetic balance type current sensor having the above configuration uses a magnetic field detection bridge circuit having a magnetoresistive effect element, particularly a GMR element or a TMR element, as a magnetic detection element. Thereby, a highly sensitive magnetic balance type current sensor can be realized.
  • this magnetic balance type current sensor is composed of two magnetoresistive effect elements having the same magnetic film detection bridge circuit.
  • the magnetic balanced current sensor having the above-described configuration can be reduced in size because the feedback coil 121, the magnetic shield 30, and the magnetic field detection bridge circuit are formed on the same substrate. Furthermore, since this magnetic balance type current sensor has no magnetic core, it can be reduced in size and cost.
  • the film configuration of the magnetoresistive effect element used in the present invention is, for example, as shown in FIG. That is, the magnetoresistive effect element has a laminated structure provided on the substrate 41 as shown in FIG. In FIG. 7A, for simplicity of explanation, the substrate 41 is shown with the base layer other than the magnetoresistive effect element omitted.
  • the magnetoresistive effect element includes a seed layer 42a, a first ferromagnetic film 43a, an antiparallel coupling film 44a, a second ferromagnetic film 45a, a nonmagnetic intermediate layer 46a, soft magnetic free layers (free magnetic layers) 47a and 48a. And a protective layer 49a.
  • the seed layer 15 is made of NiFeCr or Cr.
  • the protective layer 20 is made of Ta or the like.
  • an underlayer composed of a nonmagnetic material such as at least one element of Ta, Hf, Nb, Zr, Ti, Mo, and W, for example, between the substrate 41 and the seed layer 42a. May be provided.
  • the first ferromagnetic film 43a and the second ferromagnetic film 45a are antiferromagnetically coupled via the antiparallel coupling film 44a, so-called self-pinned ferromagnetic A fixed layer (SFP: Synthetic Ferri Pinned layer) is configured.
  • SFP Synthetic Ferri Pinned layer
  • the thickness of the antiparallel coupling film 44a is set to 0.3 nm to 0.45 nm, or 0.75 nm to 0.95 nm, so that the first ferromagnetic film 43a and the second strong film can be strengthened. Strong antiferromagnetic coupling can be brought about between the magnetic film 45a.
  • the magnetization amount (Ms ⁇ t) of the first ferromagnetic film 43a and the magnetization amount (Ms ⁇ t) of the second ferromagnetic film 45a are substantially the same. That is, the difference in magnetization between the first ferromagnetic film 43a and the second ferromagnetic film 45a is substantially zero. For this reason, the effective anisotropic magnetic field of the SFP layer is large. Therefore, the magnetization stability of the ferromagnetic pinned layer (Pin layer) can be sufficiently ensured without using an antiferromagnetic material.
  • the magnetoresistive effect element used for the magnetic balance type current sensor of the present invention has a film configuration that does not have an antiferromagnetic layer.
  • the Curie temperature (Tc) of the first ferromagnetic film 43a and the Curie temperature (Tc) of the second ferromagnetic film 45a are substantially the same. Thereby, even in a high temperature environment, the difference in magnetization (Ms ⁇ t) between the films 43a and 45a becomes substantially zero, and high magnetization stability can be maintained.
  • the first ferromagnetic film 43a is preferably made of a CoFe alloy containing 40 atomic% to 80 atomic% of Fe. This is because a CoFe alloy having this composition range has a large coercive force and can stably maintain magnetization with respect to an external magnetic field.
  • the second ferromagnetic film 45a is preferably made of a CoFe alloy containing 0 atomic% to 40 atomic% of Fe. This is because a CoFe alloy having this composition range has a small coercive force, and is easily magnetized in an antiparallel direction (a direction different by 180 °) with respect to the direction in which the first ferromagnetic film 43a is preferentially magnetized. is there. As a result, it is possible to further increase Hk represented by the above formula (1). Further, by limiting the second ferromagnetic film 45a to this composition range, it is possible to increase the resistance change rate of the magnetoresistive effect element.
  • a magnetic field is applied to the first ferromagnetic film 43a and the second ferromagnetic film 45a in the meandering stripe width direction during the film formation, and the first ferromagnetic film 43a and the second strong film 43a after the film formation are applied. It is preferable that induced magnetic anisotropy is imparted to the magnetic film 45a. As a result, both films 43a and 45a are magnetized antiparallel to the stripe width direction. Further, since the magnetization directions of the first ferromagnetic film 43a and the second ferromagnetic film 45a are determined by the magnetic field application direction during the formation of the first ferromagnetic film 43a, the first ferromagnetic film 43a is formed. It is possible to form a plurality of magnetoresistive elements having ferromagnetic pinned layers with different magnetization directions on the same substrate by changing the magnetic field application direction during film formation.
  • the antiparallel coupling film 44a of the ferromagnetic fixed layer is made of Ru or the like.
  • the soft magnetic free layers (free layers) 47a and 48a are made of a magnetic material such as a CoFe alloy, a NiFe alloy, or a CoFeNi alloy.
  • the nonmagnetic intermediate layer 46a is made of Cu or the like.
  • a magnetic field is applied to the soft magnetic free layers 47a and 48a in the longitudinal direction of the meander-shaped stripe during film formation, and induced magnetic anisotropy is imparted to the soft magnetic free layers 47a and 48a after film formation. It is preferable.
  • the resistance is linearly changed with respect to the external magnetic field (magnetic field from the current to be measured) in the stripe width direction, and the hysteresis can be reduced.
  • a spin valve configuration is adopted by a ferromagnetic fixed layer, a nonmagnetic intermediate layer, and a soft magnetic free layer.
  • the film configuration of the magnetoresistive effect element used in the magnetic balance type current sensor of the present invention for example, NiFeCr (seed layer: 5 nm) / Fe 70 Co 30 (first ferromagnetic film: 1.65 nm) / Ru (Anti-parallel coupling film: 0.4 nm) / Co 90 Fe 10 (second ferromagnetic film: 2 nm) / Cu (nonmagnetic intermediate layer: 2.2 nm) / Co 90 Fe 10 (soft magnetic free layer: 1 nm) / NiFe (soft magnetic free layer: 7 nm) / Ta (protective layer: 5 nm).
  • the magnetization directions of the films (Pin 2) are 180 ° different from each other (anti-parallel).
  • the resistance change rates of the two magnetoresistive elements 122a and 122b are the same.
  • the magnetoresistive elements 122a and 122b preferably exhibit the same rate of change in resistance at the same magnetic field strength when the angle of the applied magnetic field with respect to the ferromagnetic fixed layer is the same.
  • the voltage difference between the two outputs (Out1, Out2) of the magnetic detection bridge circuit is A canceling magnetic field is applied from the feedback coil 121 to the magnetoresistive effect element so as to be zero, and the current value flowing through the feedback coil 121 at that time is detected, thereby measuring the current to be measured. That is, as shown in FIG. 4, when the current to be measured flows in the direction of the arrow, the induced magnetic field A and the cancel magnetic field B are applied to the two magnetoresistive effect elements 122a and 122b (Out2 side), respectively. At this time, when the combined magnetic field intensity of the induced magnetic field generated by the measured current and the canceling magnetic field becomes zero, the midpoint potential difference of the magnetic detection bridge circuit becomes zero.
  • the resistance values of the fixed resistance elements 123a and 123b in the zero magnetic field and the resistance values of the magnetoresistance effect elements 122a and 122b are the same (R com ). Further, the resistance change rates of the magnetoresistive effect elements 122a and 122b are the same. Also, the output between the fixed resistance element 123a and the fixed resistance element 123b is Out1, and the output between the magnetoresistance effect element 122a and the magnetoresistance effect element 122b is Out2.
  • the resistance value of the fixed resistance element 123a is R1
  • the resistance value of the magnetoresistance effect element 122a is R2
  • the resistance value of the fixed resistance element 123b is R3
  • the resistance value of the magnetoresistance effect element 122b is R4.
  • the magnetic balanced current sensor of the present invention does not include the term ⁇ R in the denominator of the bridge midpoint potential difference equation. For this reason, the output of the midpoint potential difference shows a proportional change with respect to the induced magnetic field generated by the current I to be measured. As a result, current measurement can be performed with high accuracy.
  • a magnetic balance type current sensor using two magnetoresistive effect elements can also be manufactured by a type of magnetoresistive effect element in which the magnetization of the fixed magnetic layer is fixed by an antiferromagnetic film.
  • the exchange coupling direction of the pinned magnetic layer (Pin layer) of one of the two magnetoresistive effect elements is antiparallel to the exchange coupling direction of the pinned magnetic layer of the other magnetoresistive effect element. Therefore, it is necessary to apply laser local annealing or install a magnetic field application coil adjacent to the magnetoresistive effect element.
  • Such a method can be applied to manufacture a sensor or device having a magnetoresistive element near the outermost surface of the chip.
  • the configuration of the present invention is particularly useful in the magnetic balanced current sensor according to the present invention.
  • the magnetic detection bridge circuit and the feedback coil are integrally formed on the same substrate as in the magnetic balance type current sensor according to the present invention, it is necessary to completely insulate both of them, so that an organic insulating film such as a polyimide film is used. Will separate them.
  • the organic insulating film is generally formed by applying a heat treatment at 200 ° C. or higher after being applied by spin coating or the like. Since the organic insulating film is formed in a subsequent process of forming the magnetic detection bridge circuit, the magnetoresistive element is also heated together.
  • a magnetic field is applied so that the characteristics of the pinned magnetic layer do not deteriorate due to the thermal history of the organic insulating film formation process. It is necessary to heat-treat it.
  • the antiferromagnetic film since the antiferromagnetic film is not used, it is possible to maintain the characteristics of the fixed magnetic layer without performing a heat treatment while applying a magnetic field. Therefore, deterioration of the hysteresis of the soft magnetic free layer can be suppressed.
  • the magnetoresistive effect element of the magnetic balance type current sensor according to the present invention does not contain an antiferromagnetic material, the material cost and the manufacturing cost can be suppressed.
  • FIG. 4 For the magnetically balanced current sensor (invention) having the magnetic detection bridge circuit shown in FIG. 4, the relationship between the induced magnetic field (measured current magnetic field) due to the current to be measured and the midpoint potential difference of the magnetic detection bridge circuit was examined. . The result is shown in FIG. Further, a magnetic balance type current sensor (conventional (GMR ⁇ 1)) having a magnetic detection bridge circuit shown in FIG. 9 and a magnetic balance type current sensor (conventional (GMR ⁇ 2)) having a magnetic detection bridge circuit shown in FIG. Similarly, the relationship between the induced magnetic field due to the current to be measured (current magnetic field to be measured) and the midpoint potential difference of the magnetic detection bridge circuit was examined. The results are also shown in FIG.
  • the magnetic balanced current sensor of the present invention (the present invention) has a midpoint potential difference that changes linearly with respect to the induced magnetic field caused by the current to be measured, and performs current measurement with high accuracy. Can do.
  • the conventional magnetic balance type current sensor conventional (GMR ⁇ 1), conventional (GMR ⁇ 2)
  • the midpoint potential difference changes in a curved line with respect to the induced magnetic field due to the current to be measured, and the accuracy is high. Current measurement cannot be performed.
  • the present invention can be applied not only to a magnetic balance type current sensor, but also to a magnetic proportional type current sensor that measures a current to be measured by outputs of two magnetoresistive elements proportional to an induced magnetic field.
  • This magnetic proportional current sensor has a configuration excluding the feedback coil 121 and the magnetic shield film 30 in the configuration shown in FIG. Further, as shown in FIG. 6, the magnetic detection bridge circuit of the magnetic proportional current sensor has two magnetoresistance effect elements 122a and 122b and two fixed resistance elements 123a and 123b.
  • the magnetization directions of the ferromagnetic pinned layers (magnetization direction of the second ferromagnetic film: Pin2) of the two magnetoresistive effect elements 122a and 122b that output the midpoint potential (Out2) are 180 ° different from each other (reversely). parallel).
  • the resistance change rates of the two magnetoresistive elements 122a and 122b are the same.
  • the equation for obtaining the Out1-Out2 potential difference does not include the term ⁇ R in the denominator of the bridge midpoint potential difference equation. For this reason, the output of the midpoint potential difference shows a proportional change with respect to the induced magnetic field generated by the current I to be measured. As a result, current measurement can be performed with high accuracy.
  • the present invention is particularly useful in a magnetic proportional current sensor.
  • FIGS. 8 (a) to (c) are views for explaining a method of manufacturing a magnetoresistive element in the current sensor according to the embodiment of the present invention.
  • a seed layer 42a, a first ferromagnetic film 43a, an antiparallel coupling film 44a, a second ferromagnetic film 45a, a nonmagnetic intermediate layer 46a, a soft layer are formed on a substrate 41.
  • Magnetic free layers (free magnetic layers) 47a and 48a and a protective layer 49a are formed in sequence.
  • a magnetic field is applied in the meander-shaped stripe width direction.
  • the applied magnetic field direction is the direction from the back side to the front side of the paper
  • the applied magnetic field direction is the front side to the back side of the paper. It is the direction toward.
  • a magnetic field is applied in the longitudinal direction of the meander stripe.
  • a resist layer 50 is formed on the protective layer 49a, and the resist layer 50 is left on the region on the magnetoresistive effect element 122a side by photolithography and etching.
  • the exposed laminated film is removed by ion milling or the like to expose the substrate 41 in the region where the magnetoresistive effect element 122b is provided.
  • the applied magnetic field direction is from the front side to the back side of the paper
  • the applied magnetic field direction is from the back side of the paper to the front side. It is the direction toward.
  • a magnetic field is applied in the longitudinal direction of the meander stripe.
  • a resist layer 50 is formed on the protective layers 49a and 49b, and the resist layer 50 is formed on the formation regions of the magnetoresistive elements 122a to 122c and 123 by photolithography and etching. Remain.
  • the exposed laminated film is removed by ion milling or the like to form magnetoresistive elements 122a and 122b.
  • the magnetization directions of the self-pinned ferromagnetic fixed layers of the two magnetoresistive effect elements that output the midpoint potential in the magnetic detection bridge circuit are different from each other by 180 °. Therefore, the output of the midpoint potential difference shows a proportional change with respect to the induced magnetic field generated by the current to be measured, and current measurement can be performed with high accuracy.
  • the present invention is not limited to the above embodiment, and can be implemented with various modifications.
  • the materials, connection relations, thicknesses, sizes, manufacturing methods, and the like in the above embodiments can be changed as appropriate.
  • the present invention can be implemented with appropriate modifications without departing from the scope of the present invention.
  • the present invention can be applied to a current sensor that detects the magnitude of a current for driving a motor of an electric vehicle.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Nanotechnology (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
  • Measuring Magnetic Variables (AREA)

Abstract

L'invention porte sur un capteur de courant, qui peut mesurer un courant avec une précision élevée lorsqu'une sortie de différence de potentiel de point milieu change proportionnellement à un champ magnétique induit généré par le courant qui est mesuré. Ledit capteur de courant a un circuit de pont de détection de champ magnétique comprenant deux éléments magnétorésistifs, dont les résistances changent du fait de l'application du champ magnétique induit à partir du courant qui est mesuré, et deux éléments à résistance fixe. Les sorties du circuit de pont de détection de champ magnétique sont prises à partir de la connexion entre les deux éléments magnétorésistifs et entre les deux éléments à résistance fixe. Les deux éléments magnétorésistifs ont le même taux de changement de résistance, et chaque élément magnétorésistif a : une couche fixe ferromagnétique auto-brochée comprenant un premier film ferromagnétique et un second film ferromagnétique couplés de façon antiferromagnétique avec un film de couplage antiparallèle interposé entre ceux-ci ; une couche intermédiaire amagnétique ; et une couche libre magnétique douce. Les directions de magnétisation des couches fixes ferromagnétiques dans les éléments magnétorésistifs sont en opposition de 180° l'une par rapport à l'autre.
PCT/JP2011/054085 2010-03-12 2011-02-24 Capteur de courant WO2011111537A1 (fr)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015012313A1 (fr) * 2013-07-24 2015-01-29 ヤマハ株式会社 Circuit de détection de courant et dispositif de détection magnétique doté de celui-ci
CN105224003A (zh) * 2014-06-27 2016-01-06 雅马哈株式会社 集成电路
CN105445525A (zh) * 2014-09-24 2016-03-30 大陆汽车有限责任公司 在具有霍尔传感器的电流传感器中的过电流识别
JP2016148597A (ja) * 2015-02-13 2016-08-18 横河電機株式会社 電流センサ
JP2019138807A (ja) * 2018-02-13 2019-08-22 アルプスアルパイン株式会社 磁気センサおよび電流センサ
CN113203885A (zh) * 2020-01-31 2021-08-03 Tdk株式会社 电流传感器、磁传感器和电路

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04369278A (ja) * 1991-06-18 1992-12-22 Mitsubishi Electric Corp フルブリッジ構造の強磁性磁気抵抗素子
JPH07318591A (ja) * 1994-05-25 1995-12-08 Toyo Commun Equip Co Ltd 電流検出器
JP2004132790A (ja) * 2002-10-09 2004-04-30 Fuji Electric Holdings Co Ltd 電流センサ
JP2008249645A (ja) * 2007-03-30 2008-10-16 Tdk Corp 電流検出回路及びこの電流検出回路の初期化方法
JP2008306112A (ja) * 2007-06-11 2008-12-18 Hitachi Metals Ltd 磁気抵抗効果膜、磁気センサ及び回転角度検出装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04369278A (ja) * 1991-06-18 1992-12-22 Mitsubishi Electric Corp フルブリッジ構造の強磁性磁気抵抗素子
JPH07318591A (ja) * 1994-05-25 1995-12-08 Toyo Commun Equip Co Ltd 電流検出器
JP2004132790A (ja) * 2002-10-09 2004-04-30 Fuji Electric Holdings Co Ltd 電流センサ
JP2008249645A (ja) * 2007-03-30 2008-10-16 Tdk Corp 電流検出回路及びこの電流検出回路の初期化方法
JP2008306112A (ja) * 2007-06-11 2008-12-18 Hitachi Metals Ltd 磁気抵抗効果膜、磁気センサ及び回転角度検出装置

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9841440B2 (en) 2013-07-24 2017-12-12 Yamaha Corporation Current detection circuit and magnetic detection device provided with same
JP2015025667A (ja) * 2013-07-24 2015-02-05 ヤマハ株式会社 電流検知回路及びそれを備えた磁気検出装置
CN105431742A (zh) * 2013-07-24 2016-03-23 雅马哈株式会社 电流检测电路和配备有该电流检测电路的磁检测装置
WO2015012313A1 (fr) * 2013-07-24 2015-01-29 ヤマハ株式会社 Circuit de détection de courant et dispositif de détection magnétique doté de celui-ci
CN105224003A (zh) * 2014-06-27 2016-01-06 雅马哈株式会社 集成电路
CN105445525A (zh) * 2014-09-24 2016-03-30 大陆汽车有限责任公司 在具有霍尔传感器的电流传感器中的过电流识别
CN105445525B (zh) * 2014-09-24 2021-07-27 大陆汽车有限责任公司 在具有霍尔传感器的电流传感器中的过电流识别
JP2016148597A (ja) * 2015-02-13 2016-08-18 横河電機株式会社 電流センサ
JP2019138807A (ja) * 2018-02-13 2019-08-22 アルプスアルパイン株式会社 磁気センサおよび電流センサ
JP7057680B2 (ja) 2018-02-13 2022-04-20 アルプスアルパイン株式会社 磁気センサおよび電流センサ
CN113203885A (zh) * 2020-01-31 2021-08-03 Tdk株式会社 电流传感器、磁传感器和电路
US11789095B2 (en) 2020-01-31 2023-10-17 Tdk Corporation Current sensor, magnetic sensor and circuit
CN113203885B (zh) * 2020-01-31 2024-04-16 Tdk株式会社 电流传感器、磁传感器和电路

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