WO2018159776A1 - Magnetic sensor - Google Patents

Magnetic sensor Download PDF

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Publication number
WO2018159776A1
WO2018159776A1 PCT/JP2018/007876 JP2018007876W WO2018159776A1 WO 2018159776 A1 WO2018159776 A1 WO 2018159776A1 JP 2018007876 W JP2018007876 W JP 2018007876W WO 2018159776 A1 WO2018159776 A1 WO 2018159776A1
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Prior art keywords
magnetic field
magnetic
magnetoresistive
detection unit
operational amplifier
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PCT/JP2018/007876
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French (fr)
Japanese (ja)
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圭 田邊
笠島　多聞
晶裕 海野
将司 ▲高▼橋
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Tdk株式会社
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Publication of WO2018159776A1 publication Critical patent/WO2018159776A1/en

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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
    • 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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices

Definitions

  • the present invention relates to a magnetic sensor that converts a negative feedback current corresponding to a magnetic field to be detected into a voltage and outputs the voltage.
  • Patent Document 1 discloses a magnetic field detection sensor capable of detecting a minute magnetic field.
  • the magnetic field detection sensor includes a bridge circuit configured to connect a plurality of magnetoresistive effect elements whose resistance values change according to the direction of a magnetic field to be detected, and to output a differential voltage between predetermined connection points.
  • a magnetic body that collects the magnetic field to be detected and changes the direction of the magnetic field to be detected is disposed near the center of the bridge circuit, and the direction of the magnetic field to be detected is opposite to the direction of the magnetic field to be detected.
  • a magnetic field generating conductor that provides a magnetic field and a differential voltage of the bridge circuit are input, and a feedback current that causes the magnetic field generating conductor to generate the magnetic field that is opposite to the direction of the detection target magnetic field is supplied to the magnetic field generating conductor.
  • the magnetic field detection sensor disclosed in Patent Document 1 has a configuration in which a feedback current is converted into a voltage by a resistor and outputs the voltage.
  • the frequency characteristics of the output voltage may not be sufficient. That is, in the configuration of Patent Document 1, when the frequency of the magnetic field to be detected is increased, the output voltage is reduced, and an error in the detected magnetic field occurs.
  • the present invention has been made in recognition of such a situation, and an object of the present invention is to provide a magnetic sensor capable of improving the frequency characteristics of the output voltage.
  • One embodiment of the present invention is a magnetic sensor.
  • This magnetic sensor A magnetic detection unit including at least one magnetic detection element to which a first magnetic field to be detected is applied; A first differential amplifier to which an output voltage of the magnetic detection unit is input; A magnetic field generating conductor that generates a second magnetic field that cancels the first magnetic field in the magnetic detection unit by flowing a negative feedback current output from the first differential amplifier; A detection resistor through which the negative feedback current flows; A second differential having an inverting input terminal connected to one end of the detection resistor on the magnetic field generating conductor side, an output terminal connected to the other end of the detection resistor, and a non-inverting input terminal connected to a fixed voltage terminal And an amplifier.
  • the magnetic detection unit may include a plurality of magnetoresistive elements that are bridge-connected.
  • FIG. 2 is a schematic cross-sectional view of a magnetic detection unit and its vicinity in the magnetic sensor.
  • the schematic plan view. The wiring pattern explanatory drawing of the magnetic field generating conductor in the said magnetic sensor.
  • the schematic diagram which shows the modification of FIG. 1 is a schematic circuit diagram of a magnetic sensor according to an embodiment.
  • the schematic circuit diagram of the magnetic sensor which concerns on a comparative example. 9 is a simplified graph comparing frequency characteristics of output voltages Vout shown in FIGS. 7 and 8.
  • FIG. The simple graph which compared the frequency characteristic of the magnetic resolution of the sensor in each sensor structure of FIG.7 and FIG.8.
  • FIG. 1 is a schematic circuit diagram of a bridge circuit constituting a magnetic detection unit of a magnetic sensor according to an embodiment of the present invention.
  • the bridge circuit includes a first magnetoresistive effect element 10, a second magnetoresistive effect element 20, a third magnetoresistive effect element 30, and a fourth magnetoresistive effect element 40.
  • the fixed layer magnetization directions of the first to fourth magnetoresistive elements (10, 20, 30, 40) are the same.
  • One end of the first magnetoresistance effect element 10 and one end of the second magnetoresistance effect element 20 are connected to a first power supply line to which a first power supply voltage Vcc is supplied.
  • the other end of the first magnetoresistance effect element 10 is connected to one end of the fourth magnetoresistance effect element 40.
  • the other end of the second magnetoresistive element 20 is connected to one end of the third magnetoresistive element 30.
  • the other end of the third magnetoresistive effect element 30 and the other end of the fourth magnetoresistive effect element 40 are connected to a second power supply line to which a second power supply voltage ⁇ Vcc is supplied.
  • the voltage output to the interconnection point between the first magnetoresistance effect element 10 and the fourth magnetoresistance effect element 40 is output to Va, and the voltage output to the interconnection point between the second magnetoresistance effect element 20 and the third magnetoresistance effect element 30.
  • the voltage is Vb.
  • FIG. 2 is a schematic cross-sectional view of a magnetic detection unit and its vicinity in the magnetic sensor according to the embodiment.
  • FIG. 3 is a schematic plan view of the same. 2 and 3, the XYZ axes that are orthogonal three axes are defined. 2 and 3 also show the lines of magnetic force of the magnetic field to be detected.
  • the first to fourth magnetoresistive elements (10, 20, 30, 40) are provided in the multilayer body 5 together with the magnetic field generating conductor 70, and on the surface of the multilayer body 5 A magnetic body 80 is provided. As shown in FIG. 3, the first magnetoresistive element 10 and the third magnetoresistive element 30 have the same position in the X direction.
  • the second magnetoresistive element 20 and the fourth magnetoresistive element 40 have the same position in the X direction. Further, the first magnetoresistive element 10 and the second magnetoresistive element 20 have the same position in the Y direction. Similarly, the third magnetoresistive element 30 and the fourth magnetoresistive element 40 have the same position in the Y direction.
  • the arrangement of the first magnetoresistive effect element 10 and the third magnetoresistive effect element 30 and the arrangement of the second magnetoresistive effect element 20 and the fourth magnetoresistive effect element 40 are axisymmetric in the X direction.
  • A be the center line.
  • the magnetic body 80 is preferably disposed at a position where the center line in the X direction and the center line in the Y direction of the magnetic body 80 match A and B, respectively.
  • the magnetic body 80 extends to the Y direction side of the first magnetoresistive effect element 10 and the second magnetoresistive effect element 20, and ⁇ of the third magnetoresistive effect element 30 and the fourth magnetoresistive effect element 40. It is preferable to extend in the Y direction side. Furthermore, the magnetic body 80 is arranged such that the end face on the laminated body 5 side is closest to the first to fourth magnetoresistive elements (10, 20, 30, 40) in the Z direction, that is, the end face on the laminated body 5 side is laminated. It is preferable to be in contact with the surface of the body 5. By arranging in this way, the resistance change of the first to fourth magnetoresistance effect elements (10, 20, 30, 40) according to the change of the magnetic field to be detected is efficiently and evenly generated.
  • the layer forming the magnetic field generating conductor 70 in the multilayer body 5 is lower than the layer where the first to fourth magnetoresistance effect elements (10, 20, 30, 40) are formed (on the ⁇ Z direction side). Layer).
  • the magnetic body 80 and the first to fourth magnetoresistive elements ( 10, 20, 30, 40) can be made closer to each other in the Z direction, so that the first to fourth magnetoresistive elements (10, 20, 30, 40) can respond efficiently to changes in the detection target magnetic field. become.
  • the magnetic body 80 may be a soft magnetic body.
  • the magnetic body 80 collects the magnetic field to be detected in the Z direction, and the magnetic field to be detected is approximately the same as the fixed layer magnetization direction of the first to fourth magnetoresistive elements (10, 20, 30, 40). Change to parallel direction.
  • FIG. 4 is an explanatory diagram of a wiring pattern of the magnetic field generating conductor 70 in the magnetic sensor of the embodiment.
  • the wiring pattern of the magnetic field generating conductor 70 in the multilayer body 5 is indicated by a solid line.
  • the magnetic field generating conductor 70 is preferably formed in a single layer in the same laminate 5 as the first to fourth magnetoresistive elements (10, 20, 30, 40).
  • the magnetic field generating conductor 70 is a U-shaped planar coil that is less than one turn, but may be a planar coil that circulates a plurality of turns in a spiral shape. Both ends of the magnetic field generating conductor 70 are electrically connected to terminal portions (terminals) 71 and 72 such as through holes, respectively.
  • the magnetic field generating conductor 70 generates a second magnetic field that cancels the detection target magnetic field (first magnetic field) in each magnetoresistive effect element.
  • FIG. 5 is a schematic diagram showing the direction of the magnetic field to be detected at the position of each magnetoresistive element of the bridge circuit shown in FIG. 1 and the change in resistance value of each magnetoresistive element due to this.
  • the magnetic field to be detected is a magnetic field that is entirely parallel to the ⁇ Z direction when the magnetic body 80 is not present, and is partially bent by the presence of the magnetic body 80, so that the first to fourth magnetoresistances At the position of the effect element (10, 20, 30, 40), it has a component in the direction shown in FIG.
  • the direction of the magnetic field to be detected has a component that is the same as the magnetization direction of the fixed layer.
  • the magnetization direction of the free layer coincides with the magnetization direction of the fixed layer.
  • the resistance value changes by ⁇ R from the resistance value R0 in the absence of a magnetic field.
  • the second magnetoresistance effect element 20 since the direction of the magnetic field to be detected has a component opposite to the fixed layer magnetization direction, the free layer magnetization direction is opposite to the fixed layer magnetization direction.
  • the resistance value of the effect element 20 changes by + ⁇ R from the resistance value R0 when there is no magnetic field.
  • the resistance value of the third magnetoresistive effect element 30 changes by - ⁇ R compared to when no magnetic field is applied
  • the resistance value of the fourth magnetoresistive effect element 40 changes by + ⁇ R compared with that when no magnetic field is applied.
  • the bridge circuit of the first to fourth magnetoresistive elements (10, 20, 30, 40) has a differential output, that is, a voltage Va and a voltage Vb that change in opposite directions according to the change in the detection target magnetic field. Output is possible.
  • the differential output can be similarly performed. is there.
  • FIG. 7 is a schematic circuit diagram of the magnetic sensor according to the embodiment.
  • the first to fourth magnetoresistance effect elements (10, 20, 30, 40) connected in a bridge form a magnetic detection unit to which a first magnetic field to be detected is applied.
  • the inverting input terminal is connected to the interconnection point of the first magnetoresistive effect element 10 and the fourth magnetoresistive effect element 40, and the non-inverting input terminal is the second magnetoresistive.
  • the effect element 20 and the third magnetoresistive effect element 30 are connected to the interconnection point, and the output terminal is connected to one end of the magnetic field generating conductor 70.
  • the first operational amplifier 50 receives the output voltage (voltage Va, Vb) of the magnetic detection unit and supplies a negative feedback current to the magnetic field generating conductor 70.
  • the magnetic field generating conductor 70 generates a second magnetic field that cancels out the first magnetic field in the magnetic detection section when a negative feedback current output from the first operational amplifier 50 flows.
  • the first operational amplifier 50 is configured so that the magnetic field generating conductor 70 generates a second magnetic field that cancels the first magnetic field in the magnetic detection unit, that is, a magnetic equilibrium state is established in the magnetic detection unit.
  • a negative feedback current is supplied to the magnetic field generating conductor 70.
  • the detection resistor Rs is provided in the negative feedback current path (connected in series with the magnetic field generating conductor 70).
  • the second operational amplifier 60 as the second differential amplifier has an inverting input terminal connected to one end of the detection resistor Rs on the magnetic field generating conductor 70 side, an output terminal connected to the other end of the detection resistor Rs, and a non-inverting input. The terminal is connected to the ground as a fixed voltage terminal. Both the first operational amplifier 50 and the second operational amplifier 60 are driven by both power sources, and the first power supply line to which the first power supply voltage Vcc is supplied and the second power supply line to which the second power supply voltage ⁇ Vcc is supplied. , Respectively.
  • the voltage at the output terminal of the second operational amplifier 60 becomes the output voltage Vout as the magnetic sensor.
  • FIG. 8 is a schematic circuit diagram of a magnetic sensor according to a comparative example. Compared with the circuit shown in FIG. 7, the circuit shown in FIG. 8 eliminates the second operational amplifier 60, the other end of the detection resistor Rs is connected to the ground, and the voltage at one end of the detection resistor Rs becomes the output voltage Vout. Are different, and are otherwise identical.
  • the output voltage Vout in FIG. 8 is the same as the output voltage Vout in FIG. 7 except that the plus and minus are inverted, but the frequency characteristics are different.
  • FIG. 9 is a simplified graph comparing the frequency characteristics of the output voltages Vout shown in FIGS. This graph represents the magnitude of each output voltage Vout when the magnitude of the detection target magnetic field is constant and the frequency is changed.
  • the current-voltage conversion circuit that converts the negative feedback current into a voltage includes the second operational amplifier 60 in addition to the detection resistor Rs, so that the current-voltage conversion is performed only by the detection resistor Rs.
  • the circuit shown in FIG. 7 is configured to supply the negative feedback current by the first operational amplifier 50 and the second operational amplifier 60, and therefore the circuit of FIG. This is because the burden on the first operational amplifier 50 is reduced as compared with FIG.
  • FIG. 10 is a simplified graph comparing the frequency characteristics of the magnetic resolution of the sensors in the sensor configurations of FIGS. Due to the presence of noise called 1 / f noise whose energy is inversely proportional to the frequency, the resolution of the magnetoresistive element generally becomes better as the frequency of the magnetic field to be detected becomes higher.
  • the frequency characteristic of the first operational amplifier 50 becomes a bottleneck, and the improvement in the resolution when the frequency becomes higher is slowed above a certain frequency.
  • the frequency characteristic of the first operational amplifier 50 becomes a bottleneck when the frequency becomes high even in the high frequency region. By being reduced, the resolution becomes higher in the high frequency region, so that even higher frequency magnetic fields can be detected.
  • the current-voltage conversion circuit for converting negative feedback current into voltage has the second operational amplifier 60 in addition to the detection resistor Rs, the frequency characteristic of the output voltage Vout (for example, frequency characteristic of 100 KHz or more) can be improved. it can. This makes it possible to detect a sudden magnetic field change that could not be detected in the past.
  • the negative magnetic field generating conductor 70 is formed in the same laminate 5 as the first to fourth magnetoresistive elements (10, 20, 30, 40), it is more product than using a separate solenoid coil. In addition to being advantageous for downsizing, it is possible to suppress variations in positional accuracy during manufacturing.
  • the magnetic detection element may be another type such as a Hall element.
  • the number of magnetic detection elements is not limited to the four exemplified in the embodiment, and may be one or more arbitrary numbers.
  • a magnetic detection unit in which four magnetoresistive effect elements are connected in a full bridge has been described as an example.
  • the magnetic detection unit may be a structure in which two magnetoresistive effect elements are connected in a half bridge.
  • One magnetoresistive element and one fixed resistor may be half-bridge connected.
  • the magnetic detection element and the magnetic field generating conductor are not limited to being configured in a common laminated body, and may be provided separately from each other.
  • the magnetic detection unit, the first operational amplifier 50, and the second operational amplifier 60 are not limited to the dual power supply drive, but may be a single power supply drive.
  • a yoke may be formed between the two. By forming the yoke, more magnetic fields can be efficiently guided to the first to fourth magnetoresistive elements (10, 20, 30, 40), so that a minute magnetic field can be detected with high accuracy. Is possible.
  • the yoke is formed by a thin film process, so that it can be placed with high precision in both dimensions and position, and can be formed in the same stacking process, so the cost is lower than the parts attached to the outside. Can be reduced.

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Abstract

Provided is a magnetic sensor which makes it possible to improve the frequency characteristics of output voltage. The magnetic sensor is provided with: a magnetic detection unit including first through fourth magnetoresistive effect elements (10, 20, 30, 40) to which a first magnetic field to be detected is applied; a first operational amplifier 50 to which an output voltage of the magnetic detection unit is inputted; a magnetic field-generating conductor 70 for generating a second magnetic field canceling out the first magnetic field in the magnetic detection unit by a flow of negative feedback current outputted by the first operational amplifier 50; a detection resistor Rs to which the negative feedback current flows; and a second operational amplifier 60. The second operational amplifier 60 includes: an inverting input terminal connected to one magnetic field-generating conductor 70-side end of the detection resistor Rs; an output terminal connected to another end of the detection resistor Rs; and a non-inverting input terminal connected to ground serving as a fixed-voltage terminal.

Description

磁気センサMagnetic sensor
　本発明は、検出対象の磁界に応じた負帰還電流を電圧に変換して出力する磁気センサに関する。 The present invention relates to a magnetic sensor that converts a negative feedback current corresponding to a magnetic field to be detected into a voltage and outputs the voltage.
　下記特許文献１は、微小な磁界の検出が可能な磁界検出センサを開示する。この磁界検出センサは、検出対象磁界の向きに応じて抵抗値が変化する複数の磁気抵抗効果素子が接続され、所定の接続点間の差動電圧を出力可能なように構成されたブリッジ回路と、前記ブリッジ回路の中心付近に、前記検出対象磁界を集磁するとともに前記検出対象磁界の向きを変化させる磁性体を配置し、前記磁気抵抗効果素子に前記検出対象磁界の向きとは逆方向となる磁界を与える磁界発生導体と、前記ブリッジ回路の差動電圧が入力され、前記磁界発生導体に前記検出対象磁界の向きとは逆方向となる前記磁界を発生させる帰還電流を前記磁界発生導体に流すための差動演算回路と、前記帰還電流を電圧値として出力するための電圧変換回路と、を備える。 The following Patent Document 1 discloses a magnetic field detection sensor capable of detecting a minute magnetic field. The magnetic field detection sensor includes a bridge circuit configured to connect a plurality of magnetoresistive effect elements whose resistance values change according to the direction of a magnetic field to be detected, and to output a differential voltage between predetermined connection points. A magnetic body that collects the magnetic field to be detected and changes the direction of the magnetic field to be detected is disposed near the center of the bridge circuit, and the direction of the magnetic field to be detected is opposite to the direction of the magnetic field to be detected. A magnetic field generating conductor that provides a magnetic field and a differential voltage of the bridge circuit are input, and a feedback current that causes the magnetic field generating conductor to generate the magnetic field that is opposite to the direction of the detection target magnetic field is supplied to the magnetic field generating conductor. A differential operation circuit for flowing the voltage, and a voltage conversion circuit for outputting the feedback current as a voltage value.
特開２０１５－２１９０６１号公報Japanese Patent Laid-Open No. 2015-219061
　特許文献１の磁界検出センサは、帰還電流を抵抗によって電圧に変換して出力する構成であるが、当該構成では、出力電圧の周波数特性が十分でない場合があった。すなわち、特許文献１の構成では、検出対象の磁界の周波数が高くなると、出力電圧が低下してしまい、検出磁界の誤差が発生する問題があった。 The magnetic field detection sensor disclosed in Patent Document 1 has a configuration in which a feedback current is converted into a voltage by a resistor and outputs the voltage. However, in this configuration, the frequency characteristics of the output voltage may not be sufficient. That is, in the configuration of Patent Document 1, when the frequency of the magnetic field to be detected is increased, the output voltage is reduced, and an error in the detected magnetic field occurs.
　本発明はこうした状況を認識してなされたものであり、その目的は、出力電圧の周波数特性を向上させることの可能な磁気センサを提供することにある。 The present invention has been made in recognition of such a situation, and an object of the present invention is to provide a magnetic sensor capable of improving the frequency characteristics of the output voltage.
　本発明のある態様は、磁気センサである。この磁気センサは、
　検出対象の第１磁界が印加される少なくとも１つの磁気検出素子を含む磁気検出部と、
　前記磁気検出部の出力電圧が入力される第１差動増幅器と、
　前記第１差動増幅器が出力する負帰還電流が流れることにより、前記磁気検出部において前記第１磁界を相殺する第２磁界を発生する磁界発生導体と、
　前記負帰還電流が流れる検出抵抗と、
　反転入力端子が前記検出抵抗の前記磁界発生導体側の一端に接続され、出力端子が前記検出抵抗の他端に接続され、かつ非反転入力端子が固定電圧端子に接続された、第２差動増幅器と、を備える。 One embodiment of the present invention is a magnetic sensor. This magnetic sensor
A magnetic detection unit including at least one magnetic detection element to which a first magnetic field to be detected is applied;
A first differential amplifier to which an output voltage of the magnetic detection unit is input;
A magnetic field generating conductor that generates a second magnetic field that cancels the first magnetic field in the magnetic detection unit by flowing a negative feedback current output from the first differential amplifier;
A detection resistor through which the negative feedback current flows;
A second differential having an inverting input terminal connected to one end of the detection resistor on the magnetic field generating conductor side, an output terminal connected to the other end of the detection resistor, and a non-inverting input terminal connected to a fixed voltage terminal And an amplifier.
　前記磁気検出部は、ブリッジ接続された複数の磁気抵抗効果素子を含んでもよい。 The magnetic detection unit may include a plurality of magnetoresistive elements that are bridge-connected.
　なお、以上の構成要素の任意の組合せ、本発明の表現を方法やシステムなどの間で変換したものもまた、本発明の態様として有効である。 It should be noted that an arbitrary combination of the above-described components and a conversion of the expression of the present invention between methods and systems are also effective as an aspect of the present invention.
　本発明によれば、出力電圧の周波数特性を向上させることの可能な磁気センサを提供することができる。 According to the present invention, it is possible to provide a magnetic sensor capable of improving the frequency characteristics of the output voltage.
本発明の実施の形態に係る磁気センサの磁気検出部を構成するブリッジ回路の概略回路図。The schematic circuit diagram of the bridge circuit which comprises the magnetic detection part of the magnetic sensor which concerns on embodiment of this invention. 前記磁気センサにおける磁気検出部及びその近傍の概略断面図。FIG. 2 is a schematic cross-sectional view of a magnetic detection unit and its vicinity in the magnetic sensor. 同概略平面図。The schematic plan view. 前記磁気センサにおける磁界発生導体の配線パターン説明図。The wiring pattern explanatory drawing of the magnetic field generating conductor in the said magnetic sensor. 図１に示すブリッジ回路の各磁気抵抗効果素子の位置における検出対象磁界の向き及びそれによる各磁気抵抗効果素子の抵抗値変化を示す模式図。The schematic diagram which shows the direction of the detection object magnetic field in the position of each magnetoresistive effect element of the bridge circuit shown in FIG. 1, and the resistance value change of each magnetoresistive effect element by it. 図５の変形例を示す模式図。The schematic diagram which shows the modification of FIG. 実施の形態に係る磁気センサの概略回路図。1 is a schematic circuit diagram of a magnetic sensor according to an embodiment. 比較例に係る磁気センサの概略回路図。The schematic circuit diagram of the magnetic sensor which concerns on a comparative example. 図７及び図８の各出力電圧Ｖoutの周波数特性を比較した簡易グラフ。9 is a simplified graph comparing frequency characteristics of output voltages Vout shown in FIGS. 7 and 8. FIG. 図７及び図８の各センサ構成におけるセンサの磁気分解能の周波数特性を比較した簡易グラフ。The simple graph which compared the frequency characteristic of the magnetic resolution of the sensor in each sensor structure of FIG.7 and FIG.8.
　以下、図面を参照しながら本発明の好適な実施の形態を詳述する。なお、各図面に示される同一または同等の構成要素、部材、処理等には同一の符号を付し、適宜重複した説明は省略する。また、実施の形態は発明を限定するものではなく例示であり、実施の形態に記述されるすべての特徴やその組み合わせは必ずしも発明の本質的なものであるとは限らない。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.
　図１は、本発明の実施の形態に係る磁気センサの磁気検出部を構成するブリッジ回路の概略回路図である。このブリッジ回路は、第１磁気抵抗効果素子１０、第２磁気抵抗効果素子２０、第３磁気抵抗効果素子３０、及び第４磁気抵抗効果素子４０、を備える。第１から第４磁気抵抗効果素子（１０、２０、３０、４０）の固定層磁化方向は同じである。第１磁気抵抗効果素子１０の一端と、第２磁気抵抗効果素子２０の一端は、第１電源電圧Ｖccが供給される第１電源ラインに接続される。第１磁気抵抗効果素子１０の他端は、第４磁気抵抗効果素子４０の一端に接続される。第２磁気抵抗効果素子２０の他端は、第３磁気抵抗効果素子３０の一端に接続される。第３磁気抵抗効果素子３０の他端と、第４磁気抵抗効果素子４０の他端は、第２電源電圧－Ｖccが供給される第２電源ラインに接続される。第１磁気抵抗効果素子１０と第４磁気抵抗効果素子４０の相互接続点に出力される電圧をＶａ、第２磁気抵抗効果素子２０と第３磁気抵抗効果素子３０の相互接続点に出力される電圧をＶｂとする。 FIG. 1 is a schematic circuit diagram of a bridge circuit constituting a magnetic detection unit of a magnetic sensor according to an embodiment of the present invention. The bridge circuit includes a first magnetoresistive effect element 10, a second magnetoresistive effect element 20, a third magnetoresistive effect element 30, and a fourth magnetoresistive effect element 40. The fixed layer magnetization directions of the first to fourth magnetoresistive elements (10, 20, 30, 40) are the same. One end of the first magnetoresistance effect element 10 and one end of the second magnetoresistance effect element 20 are connected to a first power supply line to which a first power supply voltage Vcc is supplied. The other end of the first magnetoresistance effect element 10 is connected to one end of the fourth magnetoresistance effect element 40. The other end of the second magnetoresistive element 20 is connected to one end of the third magnetoresistive element 30. The other end of the third magnetoresistive effect element 30 and the other end of the fourth magnetoresistive effect element 40 are connected to a second power supply line to which a second power supply voltage −Vcc is supplied. The voltage output to the interconnection point between the first magnetoresistance effect element 10 and the fourth magnetoresistance effect element 40 is output to Va, and the voltage output to the interconnection point between the second magnetoresistance effect element 20 and the third magnetoresistance effect element 30. The voltage is Vb.
　図２は、実施の形態に係る磁気センサにおける磁気検出部及びその近傍の概略断面図である。図３は、同概略平面図である。図２及び図３により、直交三軸であるＸＹＺ軸を定義する。また、図２及び図３において、検出対象磁界の磁力線を併せて示している。本実施の形態の磁気センサにおいて、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）は、磁界発生導体７０と共に、積層体５に設けられ、積層体５の表面上には磁性体８０が設けられる。図３に示すように、 第１磁気抵抗効果素子１０と第３磁気抵抗効果素子３０は、Ｘ方向における位置が互いに等しい。同様に、第２磁気抵抗効果素子２０と第４磁気抵抗効果素子４０は、Ｘ方向における位置が互いに等しい。また、第１磁気抵抗効果素子１０と第２磁気抵抗効果素子２０は、Ｙ方向における位置が互いに等しい。同様に、第３磁気抵抗効果素子３０と第４磁気抵抗効果素子４０は、Ｙ方向における位置が互いに等しい。 FIG. 2 is a schematic cross-sectional view of a magnetic detection unit and its vicinity in the magnetic sensor according to the embodiment. FIG. 3 is a schematic plan view of the same. 2 and 3, the XYZ axes that are orthogonal three axes are defined. 2 and 3 also show the lines of magnetic force of the magnetic field to be detected. In the magnetic sensor of the present embodiment, the first to fourth magnetoresistive elements (10, 20, 30, 40) are provided in the multilayer body 5 together with the magnetic field generating conductor 70, and on the surface of the multilayer body 5 A magnetic body 80 is provided. As shown in FIG. 3, the first magnetoresistive element 10 and the third magnetoresistive element 30 have the same position in the X direction. Similarly, the second magnetoresistive element 20 and the fourth magnetoresistive element 40 have the same position in the X direction. Further, the first magnetoresistive element 10 and the second magnetoresistive element 20 have the same position in the Y direction. Similarly, the third magnetoresistive element 30 and the fourth magnetoresistive element 40 have the same position in the Y direction.
　図３において、第１磁気抵抗効果素子１０及び第３磁気抵抗効果素子３０の配置と、第２磁気抵抗効果素子２０及び第４磁気抵抗効果素子４０の配置と、が線対称となるＸ方向の中心線をＡとする。また、第１磁気抵抗効果素子１０及び第２磁気抵抗効果素子２０の配置と、第３磁気抵抗効果素子３０及び第４磁気抵抗効果素子４０の配置と、が線対称となるＹ方向の中心線をＢとする。磁性体８０は、磁性体８０のＸ方向の中心線とＹ方向の中心線がそれぞれＡとＢに合致する位置に配置されることが好ましい。また、磁性体８０は、第１磁気抵抗効果素子１０及び第２磁気抵抗効果素子２０のＹ方向側に延在し、かつ、第３磁気抵抗効果素子３０と第４磁気抵抗効果素子４０の－Ｙ方向側に延在することが好ましい。さらに、磁性体８０は、積層体５側の端面がＺ方向において第１から第４磁気抵抗効果素子（１０、２０、３０、４０）に最も近づいた配置、すなわち積層体５側の端面が積層体５の表面に接触していることが好ましい。このように配置にすることで、検出対象磁界の変化に応じた第１から第４磁気抵抗効果素子（１０、２０、３０、４０）の抵抗変化が、効率良く、さらに均等に発生することになる。また、積層体５内における、磁界発生導体７０を形成する層は、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）が形成される層よりも下層（－Ｚ方向側の層）であることが好ましい。磁界発生導体７０を第１から第４磁気抵抗効果素子（１０、２０、３０、４０）が形成される層より下層に配置することで、磁性体８０と第１から第４磁気抵抗効果素子（１０、２０、３０、４０）のＺ方向の距離を近づけることができ、これにより検出対象磁界の変化に第１から第４磁気抵抗効果素子（１０、２０、３０、４０）が効率良く応答可能になる。磁性体８０は軟磁性体であってもよい。磁性体８０は、Ｚ方向の検出対象磁界を集磁し、集磁した検出対象磁界を、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）が有する固定層磁化方向と概ね平行になる方向へ変化させる。 In FIG. 3, the arrangement of the first magnetoresistive effect element 10 and the third magnetoresistive effect element 30 and the arrangement of the second magnetoresistive effect element 20 and the fourth magnetoresistive effect element 40 are axisymmetric in the X direction. Let A be the center line. A center line in the Y direction in which the arrangement of the first magnetoresistive effect element 10 and the second magnetoresistive effect element 20 and the arrangement of the third magnetoresistive effect element 30 and the fourth magnetoresistive effect element 40 are axisymmetric. Is B. The magnetic body 80 is preferably disposed at a position where the center line in the X direction and the center line in the Y direction of the magnetic body 80 match A and B, respectively. Further, the magnetic body 80 extends to the Y direction side of the first magnetoresistive effect element 10 and the second magnetoresistive effect element 20, and − of the third magnetoresistive effect element 30 and the fourth magnetoresistive effect element 40. It is preferable to extend in the Y direction side. Furthermore, the magnetic body 80 is arranged such that the end face on the laminated body 5 side is closest to the first to fourth magnetoresistive elements (10, 20, 30, 40) in the Z direction, that is, the end face on the laminated body 5 side is laminated. It is preferable to be in contact with the surface of the body 5. By arranging in this way, the resistance change of the first to fourth magnetoresistance effect elements (10, 20, 30, 40) according to the change of the magnetic field to be detected is efficiently and evenly generated. Become. Also, the layer forming the magnetic field generating conductor 70 in the multilayer body 5 is lower than the layer where the first to fourth magnetoresistance effect elements (10, 20, 30, 40) are formed (on the −Z direction side). Layer). By disposing the magnetic field generating conductor 70 below the layer where the first to fourth magnetoresistive elements (10, 20, 30, 40) are formed, the magnetic body 80 and the first to fourth magnetoresistive elements ( 10, 20, 30, 40) can be made closer to each other in the Z direction, so that the first to fourth magnetoresistive elements (10, 20, 30, 40) can respond efficiently to changes in the detection target magnetic field. become. The magnetic body 80 may be a soft magnetic body. The magnetic body 80 collects the magnetic field to be detected in the Z direction, and the magnetic field to be detected is approximately the same as the fixed layer magnetization direction of the first to fourth magnetoresistive elements (10, 20, 30, 40). Change to parallel direction.
　図４は、実施の形態の磁気センサにおける磁界発生導体７０の配線パターン説明図である。本図では、積層体５内の磁界発生導体７０の配線パターンを実線で示している。磁界発生導体７０は、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）と同じ積層体５内の好ましくは単一の層に形成される。図４の例では、磁界発生導体７０は、１ターンに満たないＵ字状の平面コイルとしているが、スパイラル状に複数ターン周回する平面コイルであってもよい。磁界発生導体７０の両端は、スルーホール等の端子部（ターミナル）７１、７２にそれぞれ電気的に接続される。磁界発生導体７０は、図７で後述のように、各磁気抵抗効果素子において検出対象磁界（第１磁界）を相殺する第２磁界を発生する。 FIG. 4 is an explanatory diagram of a wiring pattern of the magnetic field generating conductor 70 in the magnetic sensor of the embodiment. In this figure, the wiring pattern of the magnetic field generating conductor 70 in the multilayer body 5 is indicated by a solid line. The magnetic field generating conductor 70 is preferably formed in a single layer in the same laminate 5 as the first to fourth magnetoresistive elements (10, 20, 30, 40). In the example of FIG. 4, the magnetic field generating conductor 70 is a U-shaped planar coil that is less than one turn, but may be a planar coil that circulates a plurality of turns in a spiral shape. Both ends of the magnetic field generating conductor 70 are electrically connected to terminal portions (terminals) 71 and 72 such as through holes, respectively. As will be described later with reference to FIG. 7, the magnetic field generating conductor 70 generates a second magnetic field that cancels the detection target magnetic field (first magnetic field) in each magnetoresistive effect element.
　図５は、図１に示すブリッジ回路の各磁気抵抗効果素子の位置における検出対象磁界の向き及びそれによる各磁気抵抗効果素子の抵抗値変化を示す模式図である。図５において検出対象磁界は、磁性体８０が存在しなければ全体的に－Ｚ方向と平行な磁界であり、磁性体８０があることにより部分的に曲げられて、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）の位置において図５に示す方向の成分を持つようになっている。第１磁気抵抗効果素子１０においては、検出対象磁界の方向は固定層磁化方向と同一方向となる成分を持つため、フリー層磁化方向が固定層磁化方向と一致し、第１磁気抵抗効果素子１０の抵抗値は、無磁界時の抵抗値Ｒ０から－ΔＲだけ変化する。一方、第２磁気抵抗効果素子２０においては、検出対象磁界の方向は固定層磁化方向と逆方向となる成分を持つため、フリー層磁化方向が固定層磁化方向と逆になり、第２磁気抵抗効果素子２０の抵抗値は、無磁界時の抵抗値Ｒ０から＋ΔＲだけ変化する。同様に、第３磁気抵抗効果素子３０の抵抗値は無磁界時と比較して－ΔＲだけ変化し、第４磁気抵抗効果素子４０の抵抗値は無磁界時と比較して＋ΔＲだけ変化する。このような第１から第４磁気抵抗効果素子（１０、２０、３０、４０）の抵抗変化により、電圧Ｖａは無磁界時と比較して高くなり、電圧Ｖｂは無磁界時と比較して低くなる。ゆえに、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）のブリッジ回路は、差動出力、すなわち検出対象磁界の変化に応じて互いに逆の変化をする電圧Ｖａと電圧Ｖｂの出力が可能となっている。なお、図６のようにブリッジ回路の配線を変更し、かつ第３磁気抵抗効果素子３０及び第４磁気抵抗効果素子４０の固定層磁化方向を変更しても、同様に差動出力が可能である。 FIG. 5 is a schematic diagram showing the direction of the magnetic field to be detected at the position of each magnetoresistive element of the bridge circuit shown in FIG. 1 and the change in resistance value of each magnetoresistive element due to this. In FIG. 5, the magnetic field to be detected is a magnetic field that is entirely parallel to the −Z direction when the magnetic body 80 is not present, and is partially bent by the presence of the magnetic body 80, so that the first to fourth magnetoresistances At the position of the effect element (10, 20, 30, 40), it has a component in the direction shown in FIG. In the first magnetoresistance effect element 10, the direction of the magnetic field to be detected has a component that is the same as the magnetization direction of the fixed layer. Therefore, the magnetization direction of the free layer coincides with the magnetization direction of the fixed layer. The resistance value changes by −ΔR from the resistance value R0 in the absence of a magnetic field. On the other hand, in the second magnetoresistance effect element 20, since the direction of the magnetic field to be detected has a component opposite to the fixed layer magnetization direction, the free layer magnetization direction is opposite to the fixed layer magnetization direction. The resistance value of the effect element 20 changes by + ΔR from the resistance value R0 when there is no magnetic field. Similarly, the resistance value of the third magnetoresistive effect element 30 changes by -ΔR compared to when no magnetic field is applied, and the resistance value of the fourth magnetoresistive effect element 40 changes by + ΔR compared with that when no magnetic field is applied. Due to the resistance change of the first to fourth magnetoresistive elements (10, 20, 30, 40), the voltage Va becomes higher than that in the absence of a magnetic field, and the voltage Vb becomes lower than that in the absence of a magnetic field. Become. Therefore, the bridge circuit of the first to fourth magnetoresistive elements (10, 20, 30, 40) has a differential output, that is, a voltage Va and a voltage Vb that change in opposite directions according to the change in the detection target magnetic field. Output is possible. In addition, even if the wiring of the bridge circuit is changed as shown in FIG. 6 and the fixed layer magnetization directions of the third magnetoresistive effect element 30 and the fourth magnetoresistive effect element 40 are changed, the differential output can be similarly performed. is there.
　図７は、実施の形態に係る磁気センサの概略回路図である。ブリッジ接続された第１から第４磁気抵抗効果素子（１０、２０、３０、４０）は、検出対象の第１磁界が印加される磁気検出部を構成する。第１差動増幅器としての第１演算増幅器５０は、反転入力端子が第１磁気抵抗効果素子１０と第４磁気抵抗効果素子４０の相互接続点に接続され、非反転入力端子が第２磁気抵抗効果素子２０と第３磁気抵抗効果素子３０の相互接続点に接続され、出力端子が磁界発生導体７０の一端に接続される。第１演算増幅器５０は、磁気検出部の出力電圧（電圧Ｖａ,Ｖｂ）が入力され、磁界発生導体７０に負帰還電流を供給する。磁界発生導体７０は、第１演算増幅器５０が出力する負帰還電流が流れることにより、磁気検出部において前記第１磁界を相殺する第２磁界を発生する。換言すれば、第１演算増幅器５０は、磁気検出部において前記第１磁界を相殺する第２磁界を磁界発生導体７０が発生するように、すなわち磁気検出部において磁気平衡状態が成立するように、磁界発生導体７０に負帰還電流を供給する。検出抵抗Ｒｓは、負帰還電流の経路に設けられる（磁界発生導体７０と直列接続される）。第２差動増幅器としての第２演算増幅器６０は、反転入力端子が検出抵抗Ｒｓの磁界発生導体７０側の一端に接続され、出力端子が検出抵抗Ｒｓの他端に接続され、かつ非反転入力端子が固定電圧端子としてのグランドに接続される。第１演算増幅器５０及び第２演算増幅器６０は、共に両電源駆動であり、第１電源電圧Ｖccが供給される第１電源ラインと、第２電源電圧－Ｖccが供給される第２電源ラインと、にそれぞれ接続される。第２演算増幅器６０の出力端子の電圧が、磁気センサとしての出力電圧Ｖoutとなる。図７に示すように負帰還電流をＩとすると、出力電圧Ｖoutは、Ｖout＝Ｒｓ×Ｉとなる。負帰還電流は、検出対象磁界（第１磁界）の大きさに比例するため、出力電圧Ｖoutも、検出対象磁界に比例することになり、出力電圧Ｖoutにより、検出対象磁界を検出することができる。 FIG. 7 is a schematic circuit diagram of the magnetic sensor according to the embodiment. The first to fourth magnetoresistance effect elements (10, 20, 30, 40) connected in a bridge form a magnetic detection unit to which a first magnetic field to be detected is applied. In the first operational amplifier 50 as the first differential amplifier, the inverting input terminal is connected to the interconnection point of the first magnetoresistive effect element 10 and the fourth magnetoresistive effect element 40, and the non-inverting input terminal is the second magnetoresistive. The effect element 20 and the third magnetoresistive effect element 30 are connected to the interconnection point, and the output terminal is connected to one end of the magnetic field generating conductor 70. The first operational amplifier 50 receives the output voltage (voltage Va, Vb) of the magnetic detection unit and supplies a negative feedback current to the magnetic field generating conductor 70. The magnetic field generating conductor 70 generates a second magnetic field that cancels out the first magnetic field in the magnetic detection section when a negative feedback current output from the first operational amplifier 50 flows. In other words, the first operational amplifier 50 is configured so that the magnetic field generating conductor 70 generates a second magnetic field that cancels the first magnetic field in the magnetic detection unit, that is, a magnetic equilibrium state is established in the magnetic detection unit. A negative feedback current is supplied to the magnetic field generating conductor 70. The detection resistor Rs is provided in the negative feedback current path (connected in series with the magnetic field generating conductor 70). The second operational amplifier 60 as the second differential amplifier has an inverting input terminal connected to one end of the detection resistor Rs on the magnetic field generating conductor 70 side, an output terminal connected to the other end of the detection resistor Rs, and a non-inverting input. The terminal is connected to the ground as a fixed voltage terminal. Both the first operational amplifier 50 and the second operational amplifier 60 are driven by both power sources, and the first power supply line to which the first power supply voltage Vcc is supplied and the second power supply line to which the second power supply voltage −Vcc is supplied. , Respectively. The voltage at the output terminal of the second operational amplifier 60 becomes the output voltage Vout as the magnetic sensor. As shown in FIG. 7, when the negative feedback current is I, the output voltage Vout is Vout = Rs × I. Since the negative feedback current is proportional to the magnitude of the detection target magnetic field (first magnetic field), the output voltage Vout is also proportional to the detection target magnetic field, and the detection target magnetic field can be detected by the output voltage Vout. .
　図８は、比較例に係る磁気センサの概略回路図である。図８に示す回路は、図７に示す回路と比較して、第２演算増幅器６０が無くなり、検出抵抗Ｒｓの他端がグランドに接続され、検出抵抗Ｒｓの一端の電圧が出力電圧Ｖoutとされている点で相違し、その他の点で一致する。図８における出力電圧Ｖoutは、図７における出力電圧Ｖoutと比較して、プラスマイナスが反転する他は計算上一致するが、周波数特性が異なる。 FIG. 8 is a schematic circuit diagram of a magnetic sensor according to a comparative example. Compared with the circuit shown in FIG. 7, the circuit shown in FIG. 8 eliminates the second operational amplifier 60, the other end of the detection resistor Rs is connected to the ground, and the voltage at one end of the detection resistor Rs becomes the output voltage Vout. Are different, and are otherwise identical. The output voltage Vout in FIG. 8 is the same as the output voltage Vout in FIG. 7 except that the plus and minus are inverted, but the frequency characteristics are different.
　図９は、図７及び図８の各出力電圧Ｖoutの周波数特性を比較した簡易グラフである。このグラフは、検出対象磁界の大きさを一定として周波数を変化させた場合の各出力電圧Ｖoutの大きさを表している。図７に示す実施の形態の磁気センサは、負帰還電流を電圧に変換する電流電圧変換回路が検出抵抗Ｒｓに加えて第２演算増幅器６０を含むことにより、検出抵抗Ｒｓのみで電流電圧変換を行う図８の構成と比較して、図９に示すように、より高い周波数の磁界まで検出可能となる。これは、図７に示す回路は、第１演算増幅器５０及び第２演算増幅器６０により負帰還電流を供給する構成のため、第１演算増幅器５０及のみで負帰還電流を供給する図８の回路と比較して第１演算増幅器５０への負担が低減されたことによる。 FIG. 9 is a simplified graph comparing the frequency characteristics of the output voltages Vout shown in FIGS. This graph represents the magnitude of each output voltage Vout when the magnitude of the detection target magnetic field is constant and the frequency is changed. In the magnetic sensor of the embodiment shown in FIG. 7, the current-voltage conversion circuit that converts the negative feedback current into a voltage includes the second operational amplifier 60 in addition to the detection resistor Rs, so that the current-voltage conversion is performed only by the detection resistor Rs. Compared with the configuration of FIG. 8 to be performed, as shown in FIG. 9, even higher frequency magnetic fields can be detected. This is because the circuit shown in FIG. 7 is configured to supply the negative feedback current by the first operational amplifier 50 and the second operational amplifier 60, and therefore the circuit of FIG. This is because the burden on the first operational amplifier 50 is reduced as compared with FIG.
　図１０は、図７及び図８の各センサ構成におけるセンサの磁気分解能の周波数特性を比較した簡易グラフである。１／ｆノイズと呼ばれる、エネルギーが周波数の反比例するノイズの存在により、磁気抵抗効果素子の分解能は一般に、検出対象磁界の周波数が高くなるほど良好となる。しかし、図１０に示すように、図８の比較例の構成では、第１演算増幅器５０の周波数特性がネックとなり、ある周波数以上では、周波数が高くなった場合の分解能の向上が鈍化する。これと比較して図７に示す実施の形態の回路では、第２演算増幅器６０を設けたことにより、高周波数領域においても周波数が高くなった場合、第１演算増幅器５０の周波数特性のネックが低減されることで、高周波数領域でより高分解能となるため、より高い周波数の磁界まで検出可能となる。 FIG. 10 is a simplified graph comparing the frequency characteristics of the magnetic resolution of the sensors in the sensor configurations of FIGS. Due to the presence of noise called 1 / f noise whose energy is inversely proportional to the frequency, the resolution of the magnetoresistive element generally becomes better as the frequency of the magnetic field to be detected becomes higher. However, as shown in FIG. 10, in the configuration of the comparative example of FIG. 8, the frequency characteristic of the first operational amplifier 50 becomes a bottleneck, and the improvement in the resolution when the frequency becomes higher is slowed above a certain frequency. In comparison with this, in the circuit of the embodiment shown in FIG. 7, when the second operational amplifier 60 is provided, the frequency characteristic of the first operational amplifier 50 becomes a bottleneck when the frequency becomes high even in the high frequency region. By being reduced, the resolution becomes higher in the high frequency region, so that even higher frequency magnetic fields can be detected.
　本実施の形態によれば、下記の効果を奏することができる。 According to this embodiment, the following effects can be achieved.
(1) 負帰還電流を電圧に変換する電流電圧変換回路が検出抵抗Ｒｓに加えて第２演算増幅器６０を有するため、出力電圧Ｖoutの周波数特性（例えば100KHz以上の周波数特性）を向上させることができる。これにより、従来は検出できなかった急激な磁界変化を検出可能となる。 (1) Since the current-voltage conversion circuit for converting negative feedback current into voltage has the second operational amplifier 60 in addition to the detection resistor Rs, the frequency characteristic of the output voltage Vout (for example, frequency characteristic of 100 KHz or more) can be improved. it can. This makes it possible to detect a sudden magnetic field change that could not be detected in the past.
(2) ブリッジ接続された第１から第４磁気抵抗効果素子（１０、２０、３０、４０）を磁気検出部としているため、磁界検出の分解能を高めることができる。 (2) Since the first to fourth magnetoresistive effect elements (10, 20, 30, 40) connected by the bridge are used as the magnetic detection unit, the resolution of the magnetic field detection can be increased.
(3) 負帰還電流により磁気検出部における磁気平衡を保持することにより、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）における環境温度による抵抗変化率の変化を抑え、検出精度を維持することができる。 (3) By maintaining the magnetic balance in the magnetic detector by negative feedback current, the change in the resistance change rate due to the environmental temperature in the first to fourth magnetoresistive effect elements (10, 20, 30, 40) is suppressed and detected. Accuracy can be maintained.
(4) 磁界発生導体７０は、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）と同じ積層体５内に形成されるため、別体のソレノイドコイルを用いる場合よりも製品の小型化に有利になるほか、製造時における位置精度のバラつきを抑えることが可能となる。 (4) Since the negative magnetic field generating conductor 70 is formed in the same laminate 5 as the first to fourth magnetoresistive elements (10, 20, 30, 40), it is more product than using a separate solenoid coil. In addition to being advantageous for downsizing, it is possible to suppress variations in positional accuracy during manufacturing.
　以上、実施の形態を例に本発明を説明したが、実施の形態の各構成要素や各処理プロセスには請求項に記載の範囲で種々の変形が可能であることは当業者に理解されるところである。以下、変形例について触れる。 The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.
　実施の形態では磁気検出素子が磁気抵抗効果素子である場合を説明したが、磁気検出素子は、ホール素子等の他の種類のものであってもよい。また、磁気検出素子の個数は、実施の形態で例示した４つに限定されず、１つ以上の任意の個数でよい。実施の形態では４つの磁気抵抗効果素子がフルブリッジ接続された磁気検出部を例に説明したが、磁気検出部は、２つの磁気抵抗効果素子がハーフブリッジ接続されたものであってもよいし、１つの磁気抵抗効果素子と１つの固定抵抗とがハーフブリッジ接続されたものであってもよい。磁気検出素子及び磁界発生導体は、共通の積層体に構成される場合に限定されず、互いに別々に設けられてもよい。磁気検出部、第１演算増幅器５０、及び第２演算増幅器６０は、両電源駆動に限定されず、片電源駆動であってもよい。 Although the case where the magnetic detection element is a magnetoresistive effect element has been described in the embodiment, the magnetic detection element may be another type such as a Hall element. Further, the number of magnetic detection elements is not limited to the four exemplified in the embodiment, and may be one or more arbitrary numbers. In the embodiment, a magnetic detection unit in which four magnetoresistive effect elements are connected in a full bridge has been described as an example. However, the magnetic detection unit may be a structure in which two magnetoresistive effect elements are connected in a half bridge. One magnetoresistive element and one fixed resistor may be half-bridge connected. The magnetic detection element and the magnetic field generating conductor are not limited to being configured in a common laminated body, and may be provided separately from each other. The magnetic detection unit, the first operational amplifier 50, and the second operational amplifier 60 are not limited to the dual power supply drive, but may be a single power supply drive.
　第１から第４磁気抵抗効果素子（１０、２０、３０、４０）の検出精度をさらに向上させるために、磁性体８０と第１から第４磁気抵抗効果素子（１０、２０、３０、４０）の間にヨークを形成してもよい。前記ヨークを形成することにより、第１から第４磁気抵抗効果素子（１０、２０、３０、４０）に、より多くの磁界を効率よく導くことが出来るため、微小な磁界を精度よく検出することが可能となる。また、前記ヨークは薄膜プロセスで形成することで、寸法、位置ともに精度よく配置できるだけでなく、同一の積層行程で形成できるため外部に付属させた部品より低コストとなり、製品の小型化や製造コストの削減が可能になる。 In order to further improve the detection accuracy of the first to fourth magnetoresistance effect elements (10, 20, 30, 40), the magnetic body 80 and the first to fourth magnetoresistance effect elements (10, 20, 30, 40). A yoke may be formed between the two. By forming the yoke, more magnetic fields can be efficiently guided to the first to fourth magnetoresistive elements (10, 20, 30, 40), so that a minute magnetic field can be detected with high accuracy. Is possible. In addition, the yoke is formed by a thin film process, so that it can be placed with high precision in both dimensions and position, and can be formed in the same stacking process, so the cost is lower than the parts attached to the outside. Can be reduced.
５　積層体、１０　第１磁気抵抗効果素子、２０　第２磁気抵抗効果素子、３０　第３磁気抵抗効果素子、４０　第４磁気抵抗効果素子、５０　第１演算増幅器（第１差動増幅器）、６０　第２演算増幅器（第２差動増幅器）、７０　磁界発生導体、８０　磁性体 5 laminated body, 10 first magnetoresistive effect element, 20 second magnetoresistive effect element, 30 third magnetoresistive effect element, 40 fourth magnetoresistive effect element, 50 first operational amplifier (first differential amplifier), 60 Second operational amplifier (second differential amplifier), 70 magnetic field generating conductor, 80 magnetic material

Claims (2)

  1. 　検出対象の第１磁界が印加される少なくとも１つの磁気検出素子を含む磁気検出部と、
    　前記磁気検出部の出力電圧が入力される第１差動増幅器と、
    　前記第１差動増幅器が出力する負帰還電流が流れることにより、前記磁気検出部において前記第１磁界を相殺する第２磁界を発生する磁界発生導体と、
    　前記負帰還電流が流れる検出抵抗と、
    　反転入力端子が前記検出抵抗の前記磁界発生導体側の一端に接続され、出力端子が前記検出抵抗の他端に接続され、かつ非反転入力端子が固定電圧端子に接続された、第２差動増幅器と、を備える、磁気センサ。     A magnetic detection unit including at least one magnetic detection element to which a first magnetic field to be detected is applied;
    A first differential amplifier to which an output voltage of the magnetic detection unit is input;
    A magnetic field generating conductor that generates a second magnetic field that cancels the first magnetic field in the magnetic detection unit by flowing a negative feedback current output from the first differential amplifier;
    A detection resistor through which the negative feedback current flows;
    A second differential having an inverting input terminal connected to one end of the detection resistor on the magnetic field generating conductor side, an output terminal connected to the other end of the detection resistor, and a non-inverting input terminal connected to a fixed voltage terminal And a magnetic sensor.
  2. 　前記磁気検出部は、ブリッジ接続された複数の磁気抵抗効果素子を含む、請求項１に記載の磁気センサ。 The magnetic sensor according to claim 1, wherein the magnetic detection unit includes a plurality of magnetoresistive effect elements connected in a bridge.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010085228A (en) * 2008-09-30 2010-04-15 Tdk Corp Current sensor
JP2013238580A (en) * 2011-12-28 2013-11-28 Tdk Corp Current sensor
WO2014006914A1 (en) * 2012-07-06 2014-01-09 アルプス・グリーンデバイス株式会社 Method for manufacturing current sensor, and current sensor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010085228A (en) * 2008-09-30 2010-04-15 Tdk Corp Current sensor
JP2013238580A (en) * 2011-12-28 2013-11-28 Tdk Corp Current sensor
WO2014006914A1 (en) * 2012-07-06 2014-01-09 アルプス・グリーンデバイス株式会社 Method for manufacturing current sensor, and current sensor

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