WO2019069499A1 - Current sensor and method for manufacturing current sensor - Google Patents

Current sensor and method for manufacturing current sensor Download PDF

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Publication number
WO2019069499A1
WO2019069499A1 PCT/JP2018/017864 JP2018017864W WO2019069499A1 WO 2019069499 A1 WO2019069499 A1 WO 2019069499A1 JP 2018017864 W JP2018017864 W JP 2018017864W WO 2019069499 A1 WO2019069499 A1 WO 2019069499A1
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WIPO (PCT)
Prior art keywords
sensor
gain
current
magnetic
magnetic field
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PCT/JP2018/017864
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French (fr)
Japanese (ja)
Inventor
政明 ▲高▼田
清水　康弘
宣孝 岸
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株式会社村田製作所
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Publication of WO2019069499A1 publication Critical patent/WO2019069499A1/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
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof

Definitions

  • the present invention relates to a method of manufacturing a current sensor that detects a current based on a magnetic field generated by the current and a current sensor.
  • Patent Document 1 discloses a current sensor attached to a bus bar through which current flows.
  • the current sensor of Patent Document 1 includes two magnetic sensors, two amplifiers, and an arithmetic circuit.
  • the two magnetic sensors are arranged such that their magnetic field sensing surfaces are orthogonal to each other.
  • the outputs of the respective magnetic sensors are input to the arithmetic circuit via the respective amplifier circuits.
  • the arithmetic circuit obtains measurement accuracy not depending on the mounting angle of the current sensor by calculating vector composition of vectors orthogonal to each other based on each output.
  • one amplifier is used to make the two sets of magnetic sensors and amplifiers have the same performance. The amplification resistance of is adjusted.
  • An object of the present invention is to provide a current sensor that can reduce the influence of an external magnetic field in a current sensor that detects a current based on a magnetic field generated by the current, and a method of manufacturing the same.
  • a method of manufacturing a current sensor is a method of manufacturing a current sensor that detects a current based on a magnetic field generated by a current to be detected.
  • the method includes the steps of providing a current sensor, applying an in-phase magnetic field to the current sensor, and adjusting the gain of the signal in the current sensor.
  • the current sensor includes a first magnetic sensor that senses a magnetic field, a second magnetic sensor that senses a magnetic field opposite to the magnetic field sensed by the first magnetic sensor in response to the current, and an output unit.
  • the output unit calculates differential amplification between the sensing result of the first magnetic sensor and the sensing result of the second magnetic sensor, and generates an output signal indicating the detection result of the current.
  • the in-phase magnetic field is input in phase to the first magnetic sensor and the second magnetic sensor.
  • the step of adjusting the gain adjusts the gain of the signal in the current sensor such that the amount of two signals differentially amplified at the output as the sensing results of the first and second magnetic sensors match according to the in-phase magnetic field Do.
  • a current sensor includes a first magnetic sensor, a first arithmetic unit, a second magnetic sensor, a second arithmetic unit, a third arithmetic unit, and an adjustment unit.
  • the first magnetic sensor senses a magnetic field at a first sensor gain.
  • the first operation unit multiplies the detection result of the first magnetic sensor by a first operation gain.
  • the second magnetic sensor senses a magnetic field opposite to the magnetic field sensed by the first magnetic sensor in response to the current at a second sensor gain.
  • the second operation unit multiplies the detection result of the second magnetic sensor by a second operation gain.
  • the third operation unit calculates an output signal indicating the detection result of the current based on the operation results of the first and second operation units.
  • the adjustment unit adjusts at least one of the first and second sensor gains and the first and second operation gains.
  • the adjustment unit matches the product of the first sensor gain and the first operation gain with the product of the second sensor gain and the second operation gain.
  • the influence of the external magnetic field can be reduced by adjusting the gain of the signal in the current sensor that detects the current based on the magnetic field generated by the current.
  • FIG. 6 is a view showing an example of the arrangement of an adjustment unit and a first calculation unit of the current sensor according to the first embodiment
  • Flowchart showing the adjustment method of the current sensor according to the first embodiment A diagram showing an example of a state in which an in-phase magnetic field is applied to a current sensor Diagram for explaining gain adjustment of the current sensor according to the first embodiment Diagram for explaining correction of energization of current sensor
  • FIG. 6 is a view showing an example of the arrangement of an adjustment unit and a first calculation unit of the current sensor according to the first embodiment
  • FIG. 6 is a view showing an example of the arrangement of an adjustment unit of the current sensor according to the second embodiment Block diagram showing the configuration of the current sensor according to the third embodiment Block diagram showing the configuration of the current sensor according to the fourth embodiment A diagram for explaining gain adjustment of the current sensor according to the fourth embodiment
  • the figure which shows the modification 1 of the conductor through which the electric current detected by an electric current sensor flows The figure which shows the modification 2 of the conductor through which the electric current detected by an electric current sensor flows
  • each embodiment is an example, and partial replacement or combination of the configurations shown in different embodiments is possible.
  • the description of items common to the first embodiment will be omitted, and only different points will be described.
  • the same operation and effect by the same configuration will not be sequentially referred to in each embodiment.
  • a current sensor that detects a current based on a magnetic field (hereinafter referred to as a “signal magnetic field”) generated by a current to be detected
  • a current sensor having an adjustment function for securing external magnetic field resistance
  • the external magnetic field resistance is resistance that prevents the detection result of the current from fluctuating under the influence of the external magnetic field applied from the outside separately from the signal magnetic field.
  • FIG. 1 is a perspective view illustrating the appearance of the current sensor 1 according to the first embodiment.
  • FIG. 2 is a block diagram showing the configuration of the current sensor 1 according to the present embodiment.
  • the current sensor 1 is attached to the bus bar 2 as shown in FIG. 1, for example.
  • the bus bar 2 is an example of a conductor through which the current I to be detected by the current sensor 1 flows in the longitudinal direction (Y direction).
  • the width direction of the bus bar 2 is taken as the X direction, the longitudinal direction as the Y direction, and the thickness direction as the Z direction.
  • the current sensor 1 includes two magnetic sensors 11 and 12 and an arithmetic unit 3.
  • the current sensor 1 senses a signal magnetic field due to the current I flowing through the bus bar 2 using the two magnetic sensors 11 and 12, and calculates the detection result of the current I by the arithmetic device 3.
  • the bus bar 2 is branched into two flow paths 21 and 22 in a part in the middle in the Y direction.
  • the current sensor 1 is disposed between the first and second flow paths 21 and 22.
  • the first flow path 21 is located on the + Z side of the current sensor 1
  • the second flow path 22 is located on the ⁇ Z side of the current sensor 1.
  • the current I flows through the bus bar 2 in the + Y direction
  • the current I is divided into the first flow passage 21 and the second flow passage 22.
  • the divided currents flow in the + Y direction in both the first flow path 21 and the second flow path 22.
  • the two magnetic sensors 11 and 12 are arranged, for example, in the X direction.
  • the first magnetic sensor 11 and the second magnetic sensor 12 are disposed in regions near the first flow passage 21 and the second flow passage 22, respectively, in which signal magnetic fields based on the current I are distributed in opposite phases to each other ( See Figure 6).
  • the first and second magnetic sensors 11 and 12 each include, for example, a magnetoresistive element, and have a sensitivity axis that senses a magnetic field of a uniaxial component.
  • Each of the magnetic sensors 11 and 12 is disposed, for example, so that the direction of the sensitivity axis is parallel to the X direction as appropriate within the range of tolerance. Details of the configuration of the magnetic sensors 11 and 12 will be described later.
  • the first magnetic sensor 11 has a sensor gain for magnetoelectric conversion (hereinafter referred to as “G1”).
  • the first magnetic sensor 11 generates a first sensor signal S1 indicating the sensing result of the magnetic field according to the sensor gain G1.
  • the sensor gain G1 of the first magnetic sensor 11 is an example of a first sensor gain in the present embodiment.
  • the second magnetic sensor 12 has a sensor gain for magnetoelectric conversion (hereinafter referred to as "G2").
  • the second magnetic sensor 12 generates a second sensor signal S2 indicating the sensing result of the magnetic field according to the sensor gain G2.
  • the sensor gain G2 of the second magnetic sensor 12 is an example of a second sensor gain in the present embodiment.
  • the arithmetic unit 3 includes a first arithmetic unit 31, a second arithmetic unit 32, a third arithmetic unit 33, a temperature detection unit 34, and an adjustment unit 4.
  • the arithmetic device 3 is an example of an output unit of the current sensor 1 in the present embodiment. Details of the configuration of the arithmetic device 3 will be described later.
  • the first operation unit 31 has an operation gain that indicates, for example, a magnification of 1 or more (hereinafter referred to as “A1”).
  • the first computing unit 31 receives the first sensor signal S1 from the first magnetic sensor 11, and multiplies the received first sensor signal S1 by the computing gain A1.
  • the first sensor signal S1 is output to the third arithmetic unit 33 as a first detection signal Sp1 through multiplication by the first arithmetic unit 31.
  • the first arithmetic unit 31 and the first magnetic sensor 11 constitute a magnetic detection unit 10A that generates a first detection signal Sp1.
  • the operation gain A1 of the first operation unit 31 is an example of a first operation gain in the present embodiment.
  • the second operation unit 32 has an operation gain that indicates, for example, a magnification of 1 or more (hereinafter referred to as “A2”).
  • the second operation unit 32 receives the second sensor signal S2 from the second magnetic sensor 12, and multiplies the input second sensor signal S2 by the operation gain A2.
  • the second sensor signal S2 is output to the third arithmetic unit 33 as a second detection signal Sp2 through multiplication by the second arithmetic unit 32.
  • the second arithmetic unit 32 and the second magnetic sensor 12 constitute a magnetic detection unit 10B that generates a second detection signal Sp2.
  • the operation gain A2 of the second operation unit 32 is an example of a second operation gain in the present embodiment.
  • the third calculation unit 33 has, for example, a calculation gain indicating a magnification of 1 or more.
  • the third calculation unit 33 calculates differential amplification between the first detection signal Sp1 from the first calculation unit 31 and the second detection signal Sp2 from the second calculation unit 32 in the unique calculation gain, and the calculation result To generate an output signal Sout.
  • the third calculation unit 33 outputs an output signal Sout as a detection result of the current I by the current sensor 1.
  • the third calculation unit 33 includes a temperature compensation circuit and the like.
  • the third calculation unit 33 performs temperature compensation of the output signal Sout so as to correct the fluctuation of the calculation gain or the like according to the temperature detected by the temperature detection unit 34.
  • the temperature detection unit 34 is, for example, a semiconductor temperature sensor, and detects the ambient temperature.
  • the type of the temperature detection unit 34 is not particularly limited, and, for example, a thermistor, a thermocouple, a linear positive temperature coefficient resistor, a platinum temperature measuring resistor, or the like may be used. Further, the temperature detection unit 34 may be incorporated in the temperature compensation circuit of the third calculation unit 33.
  • the adjustment unit 4 is a circuit or the like for realizing a function of adjusting various gains in the current sensor 1.
  • the adjustment unit 4 adjusts the operation gain A1 of the first operation unit 31 and / or the operation gain A2 of the second operation unit 32.
  • the adjustment unit 4 may be incorporated in the arithmetic device 3 or may be configured separately from the arithmetic device 3.
  • the external magnetic field resistance in the current sensor 1 is secured by the adjustment function of the adjustment unit 4 (details will be described later).
  • the adjustment function by the adjustment unit 4 may be realized in the analog domain or in the digital domain.
  • the first to third arithmetic units 31 to 33 may function as a buffer. Further, in the present embodiment, each of the calculation units 31 to 33 may include an offset adjustment circuit that adjusts each offset.
  • the offset indicates the deviation from the reference value of the value of the signal output from each of the calculation units 31 to 33 in the absence of the input signal.
  • the third operation unit 33 may perform temperature compensation of the offset in the output signal Sout.
  • the two magnetic sensors 11 and 12 and the arithmetic unit 3 are disposed, for example, in the same package in the current sensor 1 as shown in FIG.
  • the two magnetic sensors 11, 12 are arranged, for example, in one integrated chip.
  • By closely arranging the two magnetic sensors 11 and 12 in the same chip it is possible to improve the external magnetic field resistance in the case where the external magnetic field is spatially nonuniform.
  • the ambient temperature of the current sensor 1 has a gradient, variations in magnetoelectric conversion gain with respect to the temperature between the magnetic sensors l1 and l2 can be suppressed, and the external magnetic field resistance can be improved.
  • the first and second calculation units 31, 32 are, for example, closely arranged in the same integrated chip inside the current sensor 1. Thereby, when there is a gradient in the ambient temperature of the current sensor 1, it is possible to suppress the gain variation with respect to the temperature between the first and second calculation units 31, 32, and improve the external magnetic field resistance.
  • the two magnetic sensors 11 and 12 and the arithmetic unit 3 are wired in the shortest length so that no loop wiring occurs. Thereby, the resistance to the external magnetic field of alternating current can be improved, and the detection accuracy of the current sensor 1 can be improved.
  • FIG. 3 is a circuit diagram illustrating the configuration of the magnetic sensor 11 in the current sensor 1.
  • the magnetic sensor 11 includes four magnetoresistive elements 13a to 13d, and constitutes a Wheatstone bridge circuit.
  • the magnetic sensor 11 is driven at a constant voltage, for example, by the power supply voltage Vdd.
  • Each of the magnetoresistive elements 13a to 13d is, for example, an AMR (Anisotropic Magneto Resistance) element.
  • the series circuit of the first and second magnetoresistance elements 13a and 13b of the four magnetoresistance elements 13a to 13d and the series circuit of the third and fourth magnetoresistance elements 13c and 13d are connected in parallel. Be done.
  • the first and fourth magnetoresistance elements 13a and 13d have magnetoresistance values MR1 and MR4 that have a common tendency to increase and decrease with respect to the magnetic field input to the magnetic sensor 11.
  • the second and third magnetoresistive elements 13b and 13c have magnetoresistive values MR2 and MR3 having increasing / decreasing tendencies opposite to the magnetoresistive values MR1 and MR4 of the first and fourth magnetoresistive elements 13a and 13d.
  • the power supply voltage Vdd of the magnetic sensor 11 is supplied to the connection point between the first and third magnetoresistive elements 13a and 13c.
  • the connection point between the second and fourth magnetoresistive elements 13b and 13d is grounded.
  • a node 14p between the first and second magnetoresistance elements 13a and 13b has a potential S1p.
  • a node 14m between the third and fourth magnetoresistive elements 13c and 13d has a potential S1m.
  • the potentials S1p and S1m of the respective nodes 14p and 14m fluctuate with, for example, Vdd / 2 as the middle point potential.
  • the magnetic sensor 11 generates a sensor signal S1 as a differential signal based on the two potentials S1p and S1m.
  • the configuration of the magnetic sensor 11 described above is an example, and the present invention is not particularly limited thereto.
  • the magnetic sensor 11 may be configured by a half bridge circuit, and may generate the sensor signal S1 at a single end.
  • the magnetoresistive elements 13a to 13d are not limited to AMR elements, but various MR elements such as GMR (Giant Magneto Resistance), TMR (Tunnel Magneto Resistance), BMR (Balistic Magneto Resistance), CMR (Colossal Magneto Resistance), etc. It may be.
  • a magnetic element having a Hall element a magnetic element having a MI (Magneto Impedance) element using a magnetic impedance effect, a flux gate type magnetic element, or the like may be used.
  • a method of driving the magnetic sensors 11, 12 constant current driving, pulse driving, or the like may be employed.
  • FIG. 4 is a view showing a configuration example of the adjustment unit 4 and the first calculation unit 31 in the first embodiment.
  • FIG. 5 is a view showing a configuration example of the third calculation unit 33. As shown in FIG.
  • the adjustment unit 4 may include various circuits to which laser trim, zener zapping, resistive link, EEPROM trim, digital trim, etc. can be applied when the current sensor 1 is manufactured and shipped.
  • the adjustment unit 4 sets the first calculation unit 31 as an adjustment target will be described.
  • the second operation unit 32 can be configured in the same manner as the first operation unit 31.
  • FIGS. 4A, 4B, and 4C show first, second, and third configuration examples of the adjustment unit 4 and the first calculation unit 31, respectively.
  • the first configuration example shown in FIG. 4A is an example in which the adjustment unit 4 adjusts the operation gain A1 in the analog domain.
  • the second configuration example shown in FIG. 4B and the third configuration example shown in FIG. 4C are examples in which the adjustment unit 4 adjusts the calculation gain A1 in the digital domain.
  • the first operation unit 31 includes an amplifier 50 as shown in FIG. 4 (a).
  • the adjustment unit 4 includes the resistor 40 or the like that defines the gain of the amplifier 50, that is, the operation gain A1, and adjusts the resistance value R of the resistor 40.
  • the amplifier 50 may have a single-ended input terminal or a differential input terminal. Also, the amplifier may have a single-ended output terminal or a differential output terminal.
  • the amplifier 50 may be a buffer amplifier.
  • the first operation unit 31 includes an amplifier 50, an A / D (analog / digital) converter 51, and a digital processing unit 52.
  • the adjustment unit 4 includes, for example, an internal memory 41 such as a flash memory. The adjustment unit 4 stores a value defining the operation gain A1 in the internal memory.
  • the A / D converter 51 of the first operation unit 31 A / D converts the sensor signal S1 input via the amplifier 50.
  • the digital processing unit 52 refers to, for example, the value stored in the internal memory 41 of the adjustment unit 4, performs arithmetic processing on the A / D converted signal, and outputs the calculation result as a first detection signal Sp1.
  • the first calculation unit 31 further includes a D / A (digital / analog) converter 53 as shown in FIG. 4B in addition to the configuration of FIG. 4B.
  • the D / A converter 53 performs D / A conversion on the operation processing result of the digital processing unit 52, and outputs the conversion result as a first detection signal Sp1.
  • the D / A converter 53 may have a single-ended output terminal or may have a differential output terminal.
  • the adjustment unit 4 adjusts, for example, the calculation gain A1 with a resolution of 0.1% or less by applying the various methods described above. Thereby, the external magnetic field tolerance in the current sensor 1 can be secured with high accuracy.
  • the adjustment unit 4 may perform adjustment of the second calculation unit 32 as in the above configuration example.
  • the adjustment unit 4 may be configured to be able to adjust both of the first and second calculation units 31 and 32, or may be configured to be able to adjust only one of them.
  • FIGS. 5 (a) to 5 (g) Various configurations can also be adopted for the third arithmetic unit 33 of the arithmetic unit 3.
  • Various configuration examples of the third arithmetic unit 33 are shown in FIGS. 5 (a) to 5 (g).
  • the configuration examples shown in FIGS. 5 (a), 5 (b) and 5 (c) are examples in which the third operation unit 33 is an analog input and an analog output, respectively.
  • the third operation unit 33 may include a differential amplifier 60.
  • temperature compensation in the third operation unit 33 may be performed in the analog domain by adjusting the gain and offset of the differential amplifier 60.
  • the differential amplifier 60 may have a single-ended output terminal or may have a differential output terminal.
  • the third operation unit 33 includes an A / D converter 61, a digital processing unit 62, and a D / A converter 63, as shown in FIG. 5 (b). May be
  • the D / A converter 63 may have a single-ended output terminal or may have a differential output terminal.
  • a buffer amplifier or the like may be provided on the output side of the D / A converter 63.
  • the temperature compensation in the third operation unit 33 may be performed in the digital region in the digital processing unit 62 or the like of FIG. 5 (b). Further, in the third operation unit 33, as shown in FIG. 5C, the differential amplifier 60 may be omitted from the configuration example of FIG. 5B. In this case, the A / D converter 61 is differentially input.
  • the third arithmetic unit 33 may be configured by digital output.
  • the third operation unit 33 may be configured by omitting the D / A converter 63 from the configuration example of FIG. 5 (b).
  • the D / A converter 63 may be omitted from the configuration example of FIG. 5 (c).
  • the third arithmetic unit 33 may be configured by digital input.
  • the third arithmetic unit 33 may be configured by omitting the A / D converter 61 from the configuration example of FIG. 5 (c).
  • the third arithmetic unit 33 may include a digital processing unit 62, and may be configured as a digital input and a digital output.
  • the third calculation unit 33 configured as described above may perform various adjustments such as temperature compensation at the time of manufacture and shipping of the current sensor 1, for example.
  • the third calculation unit 33 may be adjusted by applying various methods such as laser trimming.
  • the adjustment accuracy of the third arithmetic unit 33 can improve the detection accuracy of the current sensor 1.
  • the arithmetic device 3 may also include various semiconductor integrated circuits and the like for realizing various functions of the current sensor 1.
  • the arithmetic unit 3 may include hardware circuits such as dedicated electronic circuits or reconfigurable electronic circuits designed to realize a predetermined function.
  • the arithmetic device 3 may include, for example, a CPU or the like that realizes a predetermined function in cooperation with software.
  • Arithmetic unit 3 may include an internal memory such as a flash memory, and may store various data and programs in the internal memory.
  • the arithmetic unit 3 may be configured by various semiconductor integrated circuits such as a CPU, an MPU, a microcomputer, a DSP, an FPGA, and an ASIC.
  • FIG. 6 is a diagram for explaining the relationship between the signal magnetic fields B1 and B2 and the magnetic sensors 11 and 12 in the current sensor 1.
  • FIG. 6 shows the flow paths 21 and 22 and the magnetic sensors 11 and 12 in the vicinity of the A-A ′ cross section of FIG.
  • the current flows in the same direction (for example, + Y direction) in the first flow path 21 and the second flow path 22. Therefore, the signal magnetic field B1 and the second flow near the first flow path 21
  • the signal magnetic field B2 in the vicinity of the path 22 has the same winding direction (for example, clockwise). From this, as shown in FIG. 6, in the region R1 in the vicinity of the first channel 21 and the region R2 in the vicinity of the second channel 22 between the first and second channels 21 and 22, signals passing respectively are The X components of the magnetic fields B1 and B2 are opposite to each other.
  • one magnetic sensor 11 is disposed in the region R1 near the first flow passage 21 as described above, and the other magnetic sensor 12 is in the region R2 near the second flow passage 22. Be placed. As a result, the signal magnetic fields B1 and B2 having opposite phases to each other are input to the two magnetic sensors 11 and 12, respectively.
  • the first magnetic sensor 11 generates a first sensor signal S1 according to the input magnetic field as a detection result of the signal magnetic field B1 near the first flow path 21 (see FIG. 2).
  • the second magnetic sensor 12 generates a second sensor signal S2 according to the input magnetic field as a detection result of the signal magnetic field B2 in the vicinity of the second flow path 22.
  • the magnetic fields input to the magnetic sensors 11 and 12 include not only the signal magnetic fields B1 and B2, but also noise such as a disturbance magnetic field.
  • noise is considered to be input to each of the magnetic sensors 11 and 12 in the same phase (in the same direction and with the same magnitude) by bringing the arrangement positions of the two magnetic sensors 11 and 12 close to each other.
  • the arithmetic device 3 calculates differential amplification of the sensing results of the two magnetic sensors 11 and 12 to calculate an output signal Sout indicating the detection result of the current. As a result, it is possible to offset the noise that may be included in phase with the sensing results of the respective magnetic sensors 11 and 12 and to improve the detection accuracy of the current based on the signal magnetic fields B1 and B2.
  • FIG. 7 is a diagram for explaining the external magnetic field resistance in the current sensor 1.
  • FIG. 8 is a graph illustrating the influence of the external magnetic field on various signals in the current sensor 1.
  • FIG. 7 shows a state in which the in-phase magnetic field Bc is applied as an example of the assumed external magnetic field in the flow paths 21 and 22 and the magnetic sensors 11 and 12 near the cross section similar to FIG.
  • the in-phase magnetic field Bc is a magnetic field that is input to the first magnetic sensor 11 and the second magnetic sensor 12 in phase unlike the above-described signal magnetic fields B1 and B2 (FIG. 6).
  • FIG. 8A illustrates the sensor signals S1 and S2 of the magnetic sensors 11 and 12 when the in-phase magnetic field Bc is input.
  • FIG. 8A illustrates the characteristics of the sensor signals S1 and S2 when the sensor gain G1 of the first magnetic sensor 11 and the sensor gain G2 of the second magnetic sensor 12 deviate from each other. It is assumed that the sensor gains G1 and G2 of the two magnetic sensors 11 and 12 in the current sensor 1 have manufacturing variations of, for example, about several percent. In this case, as shown in FIG. 8A, the manners (slopes of the graph) of the fluctuation of the two sensor signals S1 and S2 according to the in-phase magnetic field Bc are different from each other.
  • FIG. 8B shows an example of the detection signals Sp1 'and Sp2' based on the sensor signals S1 and S2 of FIG. 8A.
  • FIG. 8 (c) shows an output signal Sout 'based on the detection signals Sp1' and Sp2 'of FIG. 8 (b).
  • FIGS. 8B and 8C illustrate the case where the detection signals Sp1 'and Sp2' are generated without considering the variation between the two magnetic sensors 11 and 12 as described above.
  • the manners of fluctuation of the two detection signals Sp1 'and Sp2' according to the in-phase magnetic field Bc are different from each other as in the case of the two sensor signals S1 and S2. Therefore, the influence of the in-phase magnetic field Bc remains at the time of differential amplification of the two detection signals Sp1 ′ and Sp2 ′, and the output signal Sout ′ fluctuates according to the in-phase magnetic field Bc as shown in FIG. .
  • the operation gains A1 and A1 of the first and second operation units 31 and 32 in the adjustment unit 4 are appropriately set so that the following expression (1) is satisfied within the allowable error range. Adjust at least one of A2.
  • the adjustment unit 4 of the current sensor 1 according to the present embodiment is set using, for example, the in-phase magnetic field Bc at the time of manufacture and shipment of the current sensor 1.
  • FIGS. 9 is a flowchart showing a method of adjusting the current sensor 1 according to the present embodiment.
  • the flow chart of FIG. 9 is started in the state where the current sensor 1 before shipment is prepared in the inspection stage etc. at the time of manufacture shipment of the current sensor 1.
  • the current sensor 1 is prepared to a state in which the basic operation described above can be performed.
  • Each process in this flowchart is performed, for example, by an inspector using a predetermined control device (for example, a PC or various inspection devices).
  • the in-phase magnetic field Bc is applied to the current sensor 1 prepared as the adjustment target (ST1).
  • the in-phase magnetic field Bc can be generated using, for example, a Helmholtz coil.
  • the method of generating the in-phase magnetic field Bc is not particularly limited, and for example, an electromagnet or a permanent magnet may be used.
  • An example of how the generated in-phase magnetic field Bc is applied to the current sensor 1 is shown in FIG.
  • FIG. 10 shows an example in which the in-phase magnetic field Bc is applied when the current sensor 1 is attached to the bus bar 2.
  • the in-phase magnetic field Bc is applied along the X direction, and has a uniform distribution in the space region including the current sensor 1.
  • the in-phase magnetic field Bc may be applied in parallel with the direction of the sensitivity axis of each of the magnetic sensors 11 and 12 as appropriate within the range of tolerance, or may be applied without considering the direction of the sensitivity axis in particular.
  • the in-phase magnetic field Bc may have a uniform spatial distribution within the range including the two magnetic sensors 11 and 12.
  • At least one of the calculation gain A1 of the first calculation unit 31 and the calculation gain A2 of the second calculation unit 32 is adjusted using the in-phase magnetic field Bc as described above (ST2).
  • Step ST2 will be described using FIGS. 11 (a) to 11 (c).
  • FIG. 11A is a graph illustrating the relationship between the unadjusted detection signals Sp1 and Sp2 and the in-phase magnetic field Bc.
  • FIG. 11B is a graph showing the relationship between the detection signals Sp1 and Sp2 and the in-phase magnetic field Bc after adjustment of the example of FIG. 11A to step ST2.
  • FIG.11 (c) is a graph which shows the relationship between the output signal Sout and the in-phase magnetic field Bc corresponding to the state of FIG.11 (b).
  • FIG. 11A shows an example in which the amounts of change ⁇ Sp1 and ⁇ Sp2 of the detection signals Sp1 and Sp2 according to the in-phase magnetic field Bc are different from each other before the adjustment of step ST2.
  • the amounts of change .DELTA.Sp1 and .DELTA.Sp2 indicate the amount of signal that the detection signals Sp1 and Sp2 have changed from the non-applied state by the application of the in-phase magnetic field Bc.
  • the relationship between the in-phase magnetic field Bc and each of the change amounts ⁇ Sp1 and ⁇ Sp2 is expressed by the following equations (2) and (3).
  • step ST2 for example, as shown in FIGS. 11A and 11B, the adjustment unit 4 is used so that the change amount ⁇ Sp1 of the first detection signal Sp1 matches the change amount ⁇ Sp2 of the second detection signal Sp2.
  • the calculation gain A1 of the first calculation unit 31 is adjusted.
  • Step ST2 is performed by measuring the change amount ⁇ Sp1 of the first detection signal Sp1 from the first calculation unit 31 and the change amount ⁇ Sp2 of the second detection signal Sp2 from the second calculation unit 32.
  • the variation amounts ⁇ Sp1 and ⁇ Sp2 can be measured, for example, based on the values of the detection signals Sp1 and Sp2 before and after applying the in-phase magnetic field Bc.
  • step ST2 matching between the change amounts ⁇ Sp1 and ⁇ Sp2 can be appropriately performed within the range of the tolerance.
  • the tolerance is, for example, ⁇ 0.1%.
  • both can be matched by gradually changing the operation gain A1 while monitoring the respective change amounts ⁇ Sp1 and ⁇ Sp2.
  • the value of the appropriately adjusted operation gain A1 may be calculated based on the amounts of change ⁇ Sp1 and ⁇ Sp2 before adjustment of the operation gain A1 and the like.
  • the change amounts of the sensor signals S1 and S2 corresponding to G1 ⁇ Bc and G2 ⁇ Bc of the above equations (2) and (3) may be referred to.
  • step ST2 As shown in FIG. 11B, the inclination of the graph of the first detection signal Sp1 and the inclination of the graph of the second detection signal Sp2 become equal.
  • FIG. 11C By differentially inputting such first and second detection signals Sp1 and Sp2, as shown in FIG. 11C, it is possible to obtain an output signal Sout which does not fluctuate due to the in-phase magnetic field Bc. Therefore, the external magnetic field resistance in the current sensor 1 can be secured.
  • the output signal Sout includes an offset component ⁇ Ofs resulting from the signal difference ⁇ OS between the first and second detection signals Sp1 and Sp2 of FIG. 11 (b).
  • the offset component ⁇ Ofs of the output signal Sout is assumed to be a detection error when the current is detected. Therefore, in the adjustment method shown in FIG. 9, after step ST2, at least one of the offset of the first detection signal Sp1 by the first operation unit 31 and the offset of the second detection signal Sp2 by the second operation unit 32 is adjusted ( ST3).
  • step ST3 for example, the signal difference ⁇ OS between the first and second detection signals Sp1 and Sp2 in the state where the in-phase magnetic field Bc is not applied is measured.
  • the signal difference ⁇ OS may be measured in the state where the in-phase magnetic field Bc is applied.
  • step ST3 for example, the offset of the second operation unit 32 is adjusted so that the signal difference ⁇ OS between the first and second detection signals Sp1 and Sp2 is appropriately set to “0” within the allowable error range (see FIG. 11 (b)).
  • the offset component ⁇ Ofs in the output signal Sout is suppressed (see FIG. 11C), and the detection error of the current sensor 1 can be reduced.
  • the energization correction is a calibration process of adjusting the third calculation unit 33 of the current sensor 1 by supplying the current I to the bus bar 2 to which the current sensor 1 is attached.
  • the energization correction (ST4) of the current sensor 1 will be described with reference to FIG.
  • FIG. 12A is a graph showing the relationship between the sensor signals S1 and S2 and the current I in step ST4.
  • FIG. 12B is a graph illustrating the detection signals Sp1 and Sp2 which have been adjusted with respect to the sensor signals S1 and S2 of FIG. 12A.
  • FIG.12 (c) is a graph which illustrates the output signal Sout based on each detection signal Sp1 of FIG.12 (b).
  • FIG. 12A illustrates two sensor signals S1 and S2 in the case where two magnetic sensors 11 and 12 that sense a signal magnetic field based on the current I are dispersed.
  • the third operation unit 33 can generate an output signal Sout that linearly responds to the current I, as shown in FIG. 12 (c). .
  • the value of the output signal Sout that responds when the current I of a desired magnitude is supplied to the bus bar 2 is checked to adjust the gain, offset, and the like of the third arithmetic unit 33.
  • the function form of the temperature coefficient in the third calculation unit 33 can be set in advance using various parameters, and various parameters can be adjusted while monitoring temperature drift or the like of the output signal Sout during energization.
  • the adjustment method shown in FIG. 9 is completed by completing the energization correction in step ST4.
  • the current sensor 1 after adjustment is adjusted by matching the variation amounts ⁇ Sp1 and ⁇ Sp2 of the detection signals Sp1 and Sp2 according to the in-phase magnetic field Bc (ST2).
  • Formula (1) is established from (3) and (3). That is, in step ST2, the adjustment unit 4 is set so that the gain G1 ⁇ A1 of the first magnetic detection unit 10A and the gain G2 ⁇ A2 of the second magnetic detection unit 10B coincide with each other.
  • the setting for securing the external magnetic field resistance can be performed.
  • steps ST1 to ST3 are performed in a state where current sensor 1 is attached to bus bar 2 has been described, but even if current sensor 1 is not attached to bus bar 2 in steps ST1 to ST3. Good.
  • Another example of a state in which the in-phase magnetic field Bc is applied in step ST1 is shown in FIG.
  • the in-phase magnetic field Bc is applied to the current sensor 1 particularly not attached to the bus bar 2 as in the example of FIG. 10. Even in such a state, the adjustment of steps ST2 and ST3 can be performed. Thus, for example, even if the shape of the bus bar 2 to which the current sensor 1 is attached is complicated, the steps ST1 to ST3 can be easily implemented.
  • step ST4 the energization correction of step ST4 described above is performed in a state where the current sensor 1 is attached to the bus bar 2 after steps ST1 to ST3.
  • the conduction correction (ST4) is performed in a state where the current sensor unit is assembled, for example, for measurement of three-phase alternating current, when a current sensor unit in which a plurality of current sensors 1 are assembled to the bus bar 2 is manufactured. It can also be done.
  • step ST2 is not particularly limited thereto.
  • the operation gain A2 of the second operation unit 32 may be adjusted, or both operation gains A1 and A2 may be adjusted.
  • step ST3 is performed after step ST2, but step ST3 is not particularly limited to this.
  • step ST3 may be performed before steps ST1 and ST2.
  • the adjustment of step ST3 may be omitted as appropriate, in particular, when the offset adjustment of the first and second calculation units 31, 32 is not necessary.
  • the method of manufacturing the current sensor 1 is a method of manufacturing the current sensor 1 that detects the current I based on the signal magnetic fields B1 and B2 generated by the current I to be detected.
  • the method includes the steps of preparing the current sensor 1, applying the in-phase magnetic field Bc to the current sensor 1 (ST1), and adjusting the gain of the signal in the current sensor 1 (ST2).
  • the current sensor 1 includes a first magnetic sensor 11 that senses a magnetic field, and a second magnetic sensor 12 that senses a signal magnetic field B2 in reverse phase to the signal magnetic field B1 sensed by the first magnetic sensor 11 according to the current I.
  • an arithmetic unit 3 which is an example of an output unit.
  • the arithmetic unit 3 calculates differential amplification between the sensing result of the first magnetic sensor 11 and the sensing result of the second magnetic sensor 12 to generate an output signal Sout indicating the detection result of the current I.
  • the in-phase magnetic field Bc is input to the first magnetic sensor 11 and the second magnetic sensor 12 in the same phase.
  • the step of adjusting the gain includes, as an example of two signal amounts differentially amplified in the arithmetic device 3 as sensing results of the first and second magnetic sensors 11 and 12 according to the in-phase magnetic field Bc, the first and second The gain of the signal in the current sensor 1 is adjusted so that the change amounts ⁇ Sp1 and ⁇ Sp2 of the detection signals Sp1 and Sp2 match.
  • the current sensor 1 having resistance to the external magnetic field can be manufactured by adjusting the amounts of change ⁇ Sp1 and ⁇ Sp2 according to the in-phase magnetic field Bc to coincide with each other. It can be reduced.
  • the in-phase magnetic field Bc has a uniform spatial distribution.
  • the gain of the current sensor 1 can be appropriately adjusted.
  • the first magnetic sensor 11 generates the first sensor signal S1 in the sensor gain G1 (first sensor gain).
  • the second magnetic sensor 12 generates a second sensor signal S2 at a sensor gain G2 (second sensor gain).
  • the arithmetic device 3 includes a first arithmetic unit 31, a second arithmetic unit 32, and a third arithmetic unit 33.
  • the first operation unit 31 receives the first sensor signal S1 and multiplies the received signal by the operation gain A1 (first operation gain).
  • the second operation unit 32 receives the second sensor signal S2 and multiplies the input signal by the operation gain A2 (second operation gain).
  • the third operation unit 33 calculates an output signal Sout based on the operation result of the first operation unit 31 and the operation result of the second operation unit 32.
  • the step of adjusting the gain (ST2) adjusts at least one of the operation gains A1 and A2.
  • the external magnetic field resistance can be secured. Further, it is possible to make it possible to use any of the magnetic sensors 11 and 12 without the need to suppress the manufacturing variation between the two magnetic sensors 11 and 12 in the current sensor 1.
  • the step (ST2) of adjusting the gain includes the product of the sensor gain G1 and the operation gain A1 in the first magnetic detection unit 10A, and the sensor gain G2 and the operation gain A2 in the second magnetic detection unit 10B. At least one gain is adjusted to match the product (see equation (1)). Thereby, the influence of the external magnetic field in the first detection signal Sp1 and the second detection signal Sp2 can be canceled accurately, and the influence of the external magnetic field in the output signal Sout can be reduced.
  • the current sensor 1 includes the first magnetic sensor 11, the first arithmetic unit 31, the second magnetic sensor 12, the second arithmetic unit 32, the third arithmetic unit 33, and the adjustment unit 4.
  • the first magnetic sensor 11 senses a magnetic field at the sensor gain G1.
  • the first calculation unit 31 multiplies the detection result of the first magnetic sensor 11 by the calculation gain A1.
  • the second magnetic sensor 12 senses at the sensor gain G2 a signal magnetic field B2 opposite in phase to the signal magnetic field B1 sensed by the first magnetic sensor 11 according to the current I.
  • the second calculation unit 32 multiplies the detection result of the second magnetic sensor 12 by the calculation gain A2.
  • the third operation unit 33 calculates an output signal Sout indicating the detection result of the current I based on the operation results of the first and second operation units 31 and 32.
  • the adjustment unit 4 adjusts at least one of the operation gains A1 and A2.
  • the adjustment unit 4 matches the product of the sensor gain G1 and the operation gain A1 with the product of the sensor gain G2 and the operation gain A2. Thereby, in the current sensor 1, the influence of the external magnetic field can be reduced.
  • the adjustment unit 4 calculates the first operation unit according to the in-phase magnetic field Bc. At least one gain is adjusted so that the change amount ⁇ Sp1 as a signal amount indicating the calculation result of 31 and the change amount ⁇ Sp2 as the signal amount indicating the calculation result of the second calculation unit 32 match (ST2). By inputting such an in-phase magnetic field Bc, the adjustment function of the adjustment unit 4 can be confirmed.
  • the adjustment unit 4 may be set without particularly using the in-phase magnetic field Bc.
  • the setting of the adjustment unit 4 may be performed such that “A1 ⁇ G1” and “A2 ⁇ G2” match the equation (1) appropriately within the range of the allowable error.
  • the current sensor 1 in which the calculation gains A1 and A2 are adjusted has been described.
  • the external magnetic field resistance of the current sensor can be secured not only by the calculation gains A1 and A2 but also by adjusting the sensor gains G1 and G2.
  • a current sensor in which the sensor gains G1 and G2 are adjusted will be described with reference to FIGS.
  • FIG. 14 is a block diagram showing the configuration of the current sensor 1A according to the second embodiment.
  • the current sensor 1A according to the present embodiment has the same configuration as the current sensor 1 according to the first embodiment (see FIG. 2), and as shown in FIG. It is configured to adjust the sensor gains G1 and G2.
  • the adjusting unit 4A in the present embodiment like the adjusting unit 4 in the first embodiment, has the sensor gain G1 of the first magnetic sensor 11 and the sensor gain of the second magnetic sensor 12 so as to satisfy the above equation (1). Adjust at least one with G2.
  • the current sensor 1A of this embodiment can be manufactured, for example, by adjusting at least one of the sensor gains G1 and G2 using the adjusting unit 4 in step ST2 of FIG. 9 in the same manufacturing method as that of the first embodiment.
  • each sensor gain G1, G2 is adjusted by controlling the voltage or current which drives the 1st and 2nd magnetic sensor 11,12. 15 (a), (b) and (c) show first, second and third configuration examples of the adjustment unit 4A in the present embodiment.
  • the adjustment unit 4A includes a resistor 42A connected between the power supply of the power supply voltage Vdd and the first magnetic sensor 11, a power supply, and the second magnetic sensor 12 And a resistor 42B connected therebetween.
  • Each of the resistors 42A and 42B is configured such that each of the resistance values Ra and Rb is fixed or variable.
  • the adjustment unit 4A drives the drive voltage V11 supplied to the first magnetic sensor 11 and the drive voltage V12 supplied to the second magnetic sensor 12 via the respective resistors 42A and 42B.
  • the respective resistance values Ra and Rb are set, for example, in step ST2 of FIG. 9 by various methods such as laser trim, zener zapping, resistive link, EEPROM trim, digital trim and the like as in the first embodiment.
  • each of the voltage control circuits 43A and 43B includes an operational amplifier for receiving the reference voltages Vref1 and Vref2 and an NMOS transistor.
  • the voltage control circuits 43A and 43B control the drive voltages V11 and V12 of the magnetic sensors 11 and 12 to match the reference voltages Vref1 and Vref2, respectively.
  • the drive voltages V11 and V12 can be adjusted by setting the reference voltages Vref1 and Vref2 by various methods or the like as in the first configuration example described above.
  • the adjustment unit 4A generates a current control circuit 44A that generates a drive current I11 of the first magnetic sensor 11 and a drive current I12 of the second magnetic sensor 12 And a current control circuit 44B to generate.
  • each of the current control circuits 44A and 44B includes resistors having resistance values Ra and Rb, an operational amplifier for receiving the reference voltages Vref1 and Vref2, and a PMOS transistor.
  • the current control circuits 44A and 44B control the drive currents I11 and I12 of the magnetic sensors 11 and 12 as in the following equations (21) and (22), respectively. Do.
  • the drive currents I11 and I12 can be adjusted by setting the reference voltages Vref and Vref2 or the resistance values Ra and Rb based on the equations (21) and (22). Also in this configuration example, as in the first and second configuration examples, the above-described adjustment can be performed by applying various methods and the like.
  • the adjustment unit 4A of the present embodiment is configured to be able to adjust the sensor gains G1 and G2 of both of the two magnetic sensors 11 and 12 has been described.
  • the adjustment unit 4A of the present embodiment is not particularly limited thereto, and one of the sensor gains G1 and G2 of the two magnetic sensors 11 and 12 may be adjustable.
  • the adjustment unit 4A adjusts at least one of the sensor gains G1 and G2. Further, in the method of manufacturing the current sensor 1A according to the present embodiment, in the step of adjusting the gain (ST2 in FIG. 9), at least one of the sensor gains G1 and G2 is adjusted.
  • the current sensors 1 and 1A for adjusting one of the operation gains A1 and A2 and the sensor gains G1 and G2 and the method for manufacturing the same have been described.
  • the present invention is not limited to this, and a current sensor capable of adjusting both of the operation gains A1, A2 and the sensor gains G1, G2 and a method of manufacturing the same may be provided.
  • the current sensor according to the present embodiment may include an adjustment unit that adjusts at least one of two calculation gains A1 and A2 and two sensor gains G1 and G2.
  • the step of adjusting the gain at least one of the two operation gains A1 and A2 and the two sensor gains G1 and G2 may be adjusted. This can also reduce the influence of the external magnetic field in the current sensor.
  • FIG. 16 is a block diagram showing the configuration of the current sensor 1B according to the third embodiment.
  • the current sensor 1B according to the present embodiment has the same configuration as that of the current sensor 1 according to the first embodiment (see FIG. 2), and as shown in FIG. Operate based on.
  • the adjustment unit 4B in the present embodiment includes, for example, a temperature compensation circuit and the like in addition to the same configuration as that of the first embodiment.
  • the adjustment unit 4B according to the present embodiment adjusts at least one of the operation gains A1 and A2 so as not to deviate from the range of the allowable error for the equation (1), for example, according to the temperature detected by the temperature detection unit 34. .
  • the external magnetic field resistance of the current sensor 1B can be improved under various temperature environments.
  • the adjustment unit 4B may adjust the sensor gains G1 and G2 according to the temperature.
  • the temperature detection unit 34 may be incorporated in the temperature compensation circuit of the adjustment unit 4B.
  • the current sensor 1B further includes the temperature detection unit 34 that detects the ambient temperature.
  • the adjustment unit 4A adjusts at least one of the operation gains A1 and A2 and the sensor gains G1 and G2 in accordance with the temperature detected by the temperature detection unit 34. Thereby, under various temperature environments, the influence of the external magnetic field in the current sensor 1B can be reduced.
  • FIG. 17 is a block diagram showing the configuration of a current sensor 1C according to the fourth embodiment.
  • the current sensor 1C according to the present embodiment has the same configuration as the current sensor 1A of the second embodiment (see FIG. 14), and both of the first and second magnetic sensors 11A and 12A are the first and second calculation units 31A. , 32A are connected.
  • the first and second magnetic sensors 11A and 12A output differentially, and the first and second arithmetic units 31A and 32A input differentially.
  • Each magnetic sensor 11A, 12A of this embodiment is comprised similarly to the magnetic sensor 11 of the structural example of FIG. 3, for example.
  • the first magnetic sensor 11A generates sensor signals S1p and S1m which are differential from each other as expressed by the following equations (41) and (42).
  • DS1 is a signal difference between the sensor signals S1p and S1m of the first magnetic sensor 11A.
  • the signal difference DS1 is positive when, for example, the signal magnetic field B1 in the example of FIG. 6 is input.
  • the second magnetic sensor 12A similarly to the first magnetic sensor 11A, the second magnetic sensor 12A generates sensor signals S2p and S2m which are differential from each other as expressed by the following equations (43) and (44).
  • DS2 is a signal difference between the sensor signals S2p and S2m of the second magnetic sensor 12A.
  • the signal difference DS2 is positive when, for example, the signal magnetic field B2 in the example of FIG. 6 is input.
  • the first calculation unit 31A receives the sensor signal S1p from the first magnetic sensor 11A and the sensor signal S2m from the second magnetic sensor 12A, and calculates the first calculation signal So1 as in the following equation (45) Do.
  • the first calculation unit 31A calculates the multiplication of the calculation gain A1 and the subtraction between the sensor signals S1p and S2m.
  • the sensor signal S1p from the first magnetic sensor 11A is an example of a first sensor signal
  • the sensor signal S2m from the second magnetic sensor 12 is an example of a fourth sensor signal.
  • the first calculation unit 31A outputs the calculated first calculation signal So1 to the third calculation unit 33.
  • the second operation unit 32A receives the sensor signal S1m from the first magnetic sensor 11A and the sensor signal S2p from the second magnetic sensor 12A, and calculates the second operation signal So2 as in the following equation (46) Do.
  • the second calculation unit 32A calculates the multiplication of the calculation gain A2 and the subtraction between the sensor signals S1m and S2p.
  • the sensor signal S1m from the first magnetic sensor 11A is an example of a third sensor signal
  • the sensor signal S2p from the second magnetic sensor 12 is an example of a second sensor signal.
  • the second operation unit 32A outputs the calculated second operation signal So2 to the third operation unit 33.
  • the third calculation unit 33 calculates the following equation (47) based on the first calculation signal So1 from the first calculation unit 31A and the second calculation signal So2 from the second calculation unit 32A, and the detection by the current sensor 1C The resulting output signal Sout is generated.
  • the adjustment unit 4C in the present embodiment adjusts at least one of the sensor gains G1 and G2 based on the signal differences DS1 and DS2 of the two magnetic sensors 11 and 12 according to the in-phase magnetic field Bc.
  • the gain adjustment of the current sensor 1C in the present embodiment will be described with reference to FIG.
  • FIG. 18A is a graph illustrating the relationship between the signal differences DS1 and DS2 due to the unadjusted sensor gains G1 and G2 and the in-phase magnetic field Bc.
  • FIG. 18B is a graph showing the output signal Sout corresponding to the signal differences DS1 and DS2 of FIG. 18A.
  • FIG. 18 (c) is a graph showing the signal differences DS1, DS2 after adjustment from FIG. 18 (a).
  • FIG. 18 (d) is a graph showing the output signal Sout corresponding to the signal differences DS1, DS2 of FIG. 18 (c).
  • FIGS. 18A to 18D The gain adjustment of FIGS. 18A to 18D is performed using the in-phase magnetic field Bc, for example, in step ST2 of FIG.
  • the sensor gains G1 and G2 are not adjusted, the slopes of the graphs of the signal differences DS1 and DS2 of the both are different.
  • the output signal Sout fluctuates according to the in-phase magnetic field Bc.
  • change amounts ⁇ S1 and ⁇ S2 of the signal differences DS1 and DS2 corresponding to the in-phase magnetic field Bc are measured.
  • At least one of the sensor gains G1 and G2 is adjusted in the adjustment unit 4C such that both change amounts ⁇ S1 and ⁇ S2 match as appropriate within the range of the tolerance.
  • the example in which the sensor gains G1 and G2 are adjusted using the change amounts ⁇ S1 and ⁇ S2 of the signal differences DS1 and DS2 according to the in-phase magnetic field Bc has been described.
  • the adjustment of the sensor gains G1 and G2 is performed using the change amount of each operation signal So1 and So2 according to the in-phase magnetic field Bc and the change amount of the input signal to each operation unit 31A and 32A. It is also good.
  • the first magnetic sensor 11A uses the sensor gain G1 to detect the sensor signal S1p (first sensor signal) and the sensor signal S1m (different from the same signal). And a third sensor signal).
  • the second magnetic sensor 12A further generates a sensor signal S2p (second sensor signal) and a sensor signal S2m (fourth sensor signal) that is differential from the sensor signal S2p (second sensor signal) using the sensor gain G2.
  • the first calculation unit 31A receives the sensor signal S1p and the sensor signal S2m.
  • the second operation unit 32A receives the sensor signal S2p and the sensor signal S1m.
  • the step of adjusting the gain (ST2 in FIG. 9) adjusts at least one of the sensor gains G1 and G2.
  • adjustment unit 4C may operate according to the temperature detected by temperature detection part 34 like adjustment part 4B of Embodiment 3, for example.
  • the first and second calculation units 31A and 32A calculate the subtraction between the input signals (Equations (45) and (46)). Instead of subtraction, the first and second calculation units 31A and 32A may calculate addition of the input signals. In this case, for example, by replacing the sensor signals S2p and S2m that the second magnetic sensor 12A outputs to the arithmetic units 31A and 32A, the output signal Sout can be obtained as shown in equation (47a).
  • the third operation unit 33 generates the first and second magnetic fields as shown in equation (47a) by subtraction between the first and second operation signals So1 and So2 as shown in equation (47).
  • the differential amplification in which the influence of the in-phase magnetic field Bc is canceled out on the sensing results of the sensors 11A and 12A is calculated.
  • the third operation unit 33 may add the first and second operation signals So1 and So2.
  • the same result as Expression (47a) can be obtained by interchanging the sensor signals S1m and S2p input to the second arithmetic unit 32A. That is, in the third calculation unit 33, differential amplification of the sensing results of the first and second magnetic sensors 11A and 12A can be calculated.
  • bus bar 2 of FIG. 1 is described as an example of the conductor to which the current sensor 1 is attached.
  • the present invention is not limited to this and various conductors may be used. A modification of the conductor through which the current to be detected by the current sensor 1 flows will be described with reference to FIGS.
  • FIG. 19 shows a modification 1 of a conductor 2A having two flow paths 21 and 22 through which current flows.
  • FIG. 19A shows a plan view of a conductor 2A of this modification.
  • FIG. 19B illustrates a state in which the in-phase magnetic field Bc is applied to the conductor 2A of FIG. 19A.
  • the first and second flow paths 21 and 22 are connected at the + Y end in the longitudinal direction (Y direction), and are separated at the ⁇ Y end.
  • the current flowing through the conductor 2A flows in the first channel 21 in the + Y direction
  • the current flowing in the conductor 2A detours at the end on the + Y side, thereby making the second channel 22 in the -Y direction.
  • the signal magnetic fields B1 and B2 by the current are a region R10 in the vicinity of the first flow passage 21 on the same side (for example, + Z side) of the conductor 2A in the Z direction;
  • the adjacent regions R20 have opposite phases to each other.
  • the two magnetic sensors 11 and 12 are respectively a region R10 near the first flow passage 21 and a region R20 near the second flow passage 22 Will be placed.
  • the S / N ratio in the current sensor 1 can be improved to improve the detection accuracy of the current.
  • the in-phase magnetic field Bc is applied as shown in FIG. 19B, for example (ST1 in FIG. 9) .
  • gain adjustment (ST2) can be performed.
  • FIG. 20 shows a second modification of the conductor 2B in which the flow path of the current detected by the current sensor 1 is one.
  • FIGS. 20A and 20B respectively show arrangement examples of the magnetic sensors 11 and 12 in the cross-sectional view of the conductor 2B in the XZ plane.
  • the current flows in the longitudinal direction (Y direction) of the conductor 2B, and the signal magnetic field B1 by the current circulates around the conductor 2B in the XZ plane.
  • the signal magnetic field B1 has opposite phases to each other in the region R11 on the + Z side of the conductor 2B in the Z direction and the region R21 on the ⁇ Z side.
  • the two magnetic sensors 11 and 12 are respectively disposed in the region R11 on the + Z side and the region R21 on the ⁇ Z side.
  • each magnetic sensor 11 and 12 is arrange
  • the signal magnetic field B1 has the opposite phase to each other also in the region R12 on the + X side of the conductor 2B in the X direction and the region R22 on the ⁇ X side.
  • the two magnetic sensors 11 and 12 may be disposed in the region R12 on the + X side and the region R22 on the ⁇ X side, respectively.
  • each magnetic sensor 11 and 12 is arrange
  • the two magnetic sensors 11 and 12 are not limited to the above-mentioned regions R11 to R22, and can be arranged in various regions in which the signal magnetic fields B1 have opposite phases with each other via the conductor 2B.
  • FIGS. 21 (a) and 21 (b) illustrate the state in which the in-phase magnetic field Bc is applied to the conductor 2B of the modification 2 corresponding to FIGS. 20 (a) and 20 (b), respectively.
  • FIGS. 21 (a) and 21 (b) Apply (ST1 in FIG. 9).
  • the direction in which the in-phase magnetic field Bc is applied can be set as appropriate without being limited to FIGS. 21 (a) and 21 (b).
  • the two magnetic sensors 11 and 12 are arranged to face each other via the conductor 2B through which the current flows. This also makes it possible to improve the detection accuracy of the current by improving the S / N ratio in the current sensor 1.

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Abstract

Provided is a method for manufacturing a current sensor that detects a current on the basis of a magnetic field generated by a to-be-detected current. This method includes: a step for preparing a current sensor (1); a step (ST1) for applying an in-phase magnetic field (Bc) to the current sensor; and a step (ST2) for adjusting gain. The current sensor is provided with: first and second magnetic sensors that sense magnetic fields (B1, B2) having mutually reversed phases in accordance with a current (I); and an output unit. The output unit calculates a differential amplification between the sensing result of the first magnetic sensor and the sensing result of the second magnetic sensor, and generates an output signal that indicates the detection result of a current. The in-phase magnetic field is inputted in phase to the first magnetic sensor and the second magnetic sensor. In the step for adjusting gain, the gain of the signal in the current sensor is adjusted, in accordance with the in-phase magnetic field, such that the amounts of two signals, on which differential amplification is performed by the output unit as the sensing results of the first and second magnetic sensors, are equal to each other.

Description

電流センサの製造方法および電流センサMethod of manufacturing current sensor and current sensor
　本発明は、電流によって生じる磁場に基づいて電流を検出する電流センサの製造方法および電流センサに関する。 The present invention relates to a method of manufacturing a current sensor that detects a current based on a magnetic field generated by the current and a current sensor.
　特許文献１は、電流が流れるバスバーに取り付けられる電流センサを開示している。特許文献１の電流センサは、２つの磁気センサと、２つの増幅器と、演算回路とを備えている。２つの磁気センサは、互いの磁界感知面が直交するように配置されている。各々の磁気センサの出力は、それぞれの増幅回路を介して演算回路に入力されている。演算回路は、各々の出力に基づいて、互いに直交するベクトルのベクトル合成を演算することにより、電流センサの取り付け角度に依らない計測精度を得ている。特許文献１では、上記のようにバスバーへの取り付け誤差に対して計測精度を維持する目的で２つの磁気センサを用いる際に、２組の磁気センサ及び増幅器を同一性能にするべく、一方の増幅器の増幅抵抗が調整されている。 Patent Document 1 discloses a current sensor attached to a bus bar through which current flows. The current sensor of Patent Document 1 includes two magnetic sensors, two amplifiers, and an arithmetic circuit. The two magnetic sensors are arranged such that their magnetic field sensing surfaces are orthogonal to each other. The outputs of the respective magnetic sensors are input to the arithmetic circuit via the respective amplifier circuits. The arithmetic circuit obtains measurement accuracy not depending on the mounting angle of the current sensor by calculating vector composition of vectors orthogonal to each other based on each output. In the patent document 1, when using two magnetic sensors for the purpose of maintaining measurement accuracy with respect to a mounting error to a bus bar as described above, one amplifier is used to make the two sets of magnetic sensors and amplifiers have the same performance. The amplification resistance of is adjusted.
特開２００２－３３３４５６号公報JP 2002-333456 A
　本発明の目的は、電流によって生じる磁場に基づいて電流を検出する電流センサにおいて、外部磁場の影響を低減することができる電流センサ及びその製造方法を提供することにある。 An object of the present invention is to provide a current sensor that can reduce the influence of an external magnetic field in a current sensor that detects a current based on a magnetic field generated by the current, and a method of manufacturing the same.
　本発明に係る電流センサの製造方法は、検出対象の電流によって生じる磁場に基づき電流を検出する電流センサの製造方法である。本方法は、電流センサを準備する工程と、同相磁場を電流センサに印加する工程と、電流センサにおける信号のゲインを調整する工程とを含む。電流センサは、磁場を感知する第１磁気センサと、電流に応じて第１磁気センサが感知する磁場とは逆相の磁場を感知する第２磁気センサと、出力部とを備える。出力部は、第１磁気センサの感知結果と第２磁気センサの感知結果との差動増幅を演算して、電流の検出結果を示す出力信号を生成する。同相磁場は、第１磁気センサと第２磁気センサとに同相で入力される。ゲインを調整する工程は、同相磁場に応じて、第１及び第２磁気センサの感知結果として出力部に差動増幅される２つの信号量が合致するように、電流センサにおける信号のゲインを調整する。 A method of manufacturing a current sensor according to the present invention is a method of manufacturing a current sensor that detects a current based on a magnetic field generated by a current to be detected. The method includes the steps of providing a current sensor, applying an in-phase magnetic field to the current sensor, and adjusting the gain of the signal in the current sensor. The current sensor includes a first magnetic sensor that senses a magnetic field, a second magnetic sensor that senses a magnetic field opposite to the magnetic field sensed by the first magnetic sensor in response to the current, and an output unit. The output unit calculates differential amplification between the sensing result of the first magnetic sensor and the sensing result of the second magnetic sensor, and generates an output signal indicating the detection result of the current. The in-phase magnetic field is input in phase to the first magnetic sensor and the second magnetic sensor. The step of adjusting the gain adjusts the gain of the signal in the current sensor such that the amount of two signals differentially amplified at the output as the sensing results of the first and second magnetic sensors match according to the in-phase magnetic field Do.
　本発明に係る電流センサは、第１磁気センサと、第１演算部と、第２磁気センサと、第２演算部と、第３演算部と、調整部とを備える。第１磁気センサは、第１のセンサゲインにおいて磁場を感知する。第１演算部は、第１磁気センサの感知結果に第１の演算ゲインを乗算する。第２磁気センサは、電流に応じて第１磁気センサが感知する磁場とは逆相の磁場を、第２のセンサゲインにおいて感知する。第２演算部は、第２磁気センサの感知結果に第２の演算ゲインを乗算する。第３演算部は、第１及び第２演算部の演算結果に基づき電流の検出結果を示す出力信号を算出する。調整部は、第１及び第２のセンサゲイン並びに第１及び第２の演算ゲインのうちの少なくとも１つのゲインを調整する。調整部は、第１のセンサゲインと第１の演算ゲインの積と、第２のセンサゲインと第２の演算ゲインの積とを合致させる。 A current sensor according to the present invention includes a first magnetic sensor, a first arithmetic unit, a second magnetic sensor, a second arithmetic unit, a third arithmetic unit, and an adjustment unit. The first magnetic sensor senses a magnetic field at a first sensor gain. The first operation unit multiplies the detection result of the first magnetic sensor by a first operation gain. The second magnetic sensor senses a magnetic field opposite to the magnetic field sensed by the first magnetic sensor in response to the current at a second sensor gain. The second operation unit multiplies the detection result of the second magnetic sensor by a second operation gain. The third operation unit calculates an output signal indicating the detection result of the current based on the operation results of the first and second operation units. The adjustment unit adjusts at least one of the first and second sensor gains and the first and second operation gains. The adjustment unit matches the product of the first sensor gain and the first operation gain with the product of the second sensor gain and the second operation gain.
　本発明に係る電流センサ及びその製造方法によると、電流によって生じる磁場に基づいて電流を検出する電流センサにおける信号のゲインが調整されることにより、外部磁場の影響を低減することができる。 According to the current sensor and the method of manufacturing the same according to the present invention, the influence of the external magnetic field can be reduced by adjusting the gain of the signal in the current sensor that detects the current based on the magnetic field generated by the current.
実施形態１に係る電流センサの外観を例示する斜視図The perspective view which illustrates the appearance of the current sensor concerning Embodiment 1 実施形態１に係る電流センサの構成を示すブロック図Block diagram showing the configuration of the current sensor according to the first embodiment 電流センサにおける磁気センサの構成を例示する回路図A circuit diagram illustrating the configuration of a magnetic sensor in a current sensor 実施形態１に係る電流センサの調整部及び第１演算部の構成例を示す図FIG. 6 is a view showing an example of the arrangement of an adjustment unit and a first calculation unit of the current sensor according to the first embodiment 電流センサにおける第３演算部の構成例を示す図The figure which shows the structural example of the 3rd calculating part in a current sensor 電流センサにおける信号磁場と磁気センサとの関係を説明するための図Diagram for explaining the relationship between the signal magnetic field and the magnetic sensor in the current sensor 電流センサにおける外部磁場耐性を説明するための図Diagram for explaining resistance to external magnetic field in current sensor 電流センサにおける各種信号に対する外部磁場の影響を例示するグラフGraph illustrating the effect of external magnetic fields on various signals in a current sensor 実施形態１に係る電流センサの調整方法を示すフローチャートFlowchart showing the adjustment method of the current sensor according to the first embodiment 電流センサに同相磁場が印加される状態の一例を示す図A diagram showing an example of a state in which an in-phase magnetic field is applied to a current sensor 実施形態１に係る電流センサのゲイン調整を説明するための図Diagram for explaining gain adjustment of the current sensor according to the first embodiment 電流センサの通電補正を説明するための図Diagram for explaining correction of energization of current sensor 電流センサに同相磁場が印加される状態の別例を示す図The figure which shows another example of the state to which an in-phase magnetic field is applied to a current sensor 実施形態２に係る電流センサの構成を示すブロック図Block diagram showing the configuration of the current sensor according to the second embodiment 実施形態２に係る電流センサの調整部の構成例を示す図FIG. 6 is a view showing an example of the arrangement of an adjustment unit of the current sensor according to the second embodiment 実施形態３に係る電流センサの構成を示すブロック図Block diagram showing the configuration of the current sensor according to the third embodiment 実施形態４に係る電流センサの構成を示すブロック図Block diagram showing the configuration of the current sensor according to the fourth embodiment 実施形態４に係る電流センサのゲイン調整を説明するための図A diagram for explaining gain adjustment of the current sensor according to the fourth embodiment 電流センサに検出される電流が流れる導体の変形例１を示す図The figure which shows the modification 1 of the conductor through which the electric current detected by an electric current sensor flows 電流センサに検出される電流が流れる導体の変形例２を示す図The figure which shows the modification 2 of the conductor through which the electric current detected by an electric current sensor flows 変形例２において同相磁場が印加される状態を例示する図The figure which illustrates the state to which the in-phase magnetic field is applied in modification 2
　以下、添付の図面を参照して本発明に係る電流センサ及びその製造方法の実施形態を説明する。 Hereinafter, embodiments of a current sensor and a method of manufacturing the same according to the present invention will be described with reference to the accompanying drawings.
　各実施形態は例示であり、異なる実施形態で示した構成の部分的な置換または組み合わせが可能であることは言うまでもない。実施形態２以降では実施形態１と共通の事項についての記述を省略し、異なる点についてのみ説明する。特に、同様の構成による同様の作用効果については、実施形態毎には逐次言及しない。 It goes without saying that each embodiment is an example, and partial replacement or combination of the configurations shown in different embodiments is possible. In the second and subsequent embodiments, the description of items common to the first embodiment will be omitted, and only different points will be described. In particular, the same operation and effect by the same configuration will not be sequentially referred to in each embodiment.
（実施形態１）
　実施形態１では、検出対象の電流によって生じる磁場（以下「信号磁場」という）に基づいて電流を検出する電流センサにおいて、外部磁場耐性を確保するための調整機能を有する電流センサを提供する。外部磁場耐性は、信号磁場とは別に外部から印加される外部磁場の影響によって、電流の検出結果が変動しないようにする耐性である。 (Embodiment 1)
In the first embodiment, in a current sensor that detects a current based on a magnetic field (hereinafter referred to as a “signal magnetic field”) generated by a current to be detected, a current sensor having an adjustment function for securing external magnetic field resistance is provided. The external magnetic field resistance is resistance that prevents the detection result of the current from fluctuating under the influence of the external magnetic field applied from the outside separately from the signal magnetic field.
１．構成
　実施形態１に係る電流センサの構成について、図１，２を用いて説明する。図１は、実施形態１に係る電流センサ１の外観を例示する斜視図である。図２は、本実施形態に係る電流センサ１の構成を示すブロック図である。 1. Configuration The configuration of the current sensor according to the first embodiment will be described with reference to FIGS. FIG. 1 is a perspective view illustrating the appearance of the current sensor 1 according to the first embodiment. FIG. 2 is a block diagram showing the configuration of the current sensor 1 according to the present embodiment.
　電流センサ１は、例えば図１に示すように、バスバー２に取り付けられる。バスバー２は、長手方向（Ｙ方向）に電流センサ１の検出対象の電流Ｉが流れる導体の一例である。以下、バスバー２の幅方向をＸ方向とし、長手方向をＹ方向とし、厚さ方向をＺ方向とする。 The current sensor 1 is attached to the bus bar 2 as shown in FIG. 1, for example. The bus bar 2 is an example of a conductor through which the current I to be detected by the current sensor 1 flows in the longitudinal direction (Y direction). Hereinafter, the width direction of the bus bar 2 is taken as the X direction, the longitudinal direction as the Y direction, and the thickness direction as the Z direction.
　本実施形態に係る電流センサ１は、図２に示すように、２つの磁気センサ１１，１２と、演算装置３とを備える。電流センサ１は、２つの磁気センサ１１，１２を用いて、バスバー２に流れる電流Ｉによる信号磁場を感知して、電流Ｉの検出結果を演算装置３で算出する。 As shown in FIG. 2, the current sensor 1 according to the present embodiment includes two magnetic sensors 11 and 12 and an arithmetic unit 3. The current sensor 1 senses a signal magnetic field due to the current I flowing through the bus bar 2 using the two magnetic sensors 11 and 12, and calculates the detection result of the current I by the arithmetic device 3.
　バスバー２は、Ｙ方向における途中の一部分において、２つの流路２１，２２に分岐されている。電流センサ１は、第１及び第２流路２１，２２間に配置されている。第１流路２１は電流センサ１よりも＋Ｚ側に位置し、第２流路２２は電流センサ１よりも－Ｚ側に位置する。図１に例示するように、電流Ｉがバスバー２を＋Ｙ向きに流れると、第１流路２１と第２流路２２とに分流する。分流した各々の電流は、第１流路２１と第２流路２２との双方において＋Ｙ向きに流れる。 The bus bar 2 is branched into two flow paths 21 and 22 in a part in the middle in the Y direction. The current sensor 1 is disposed between the first and second flow paths 21 and 22. The first flow path 21 is located on the + Z side of the current sensor 1, and the second flow path 22 is located on the −Z side of the current sensor 1. As illustrated in FIG. 1, when the current I flows through the bus bar 2 in the + Y direction, the current I is divided into the first flow passage 21 and the second flow passage 22. The divided currents flow in the + Y direction in both the first flow path 21 and the second flow path 22.
　電流センサ１において、２つの磁気センサ１１，１２は、例えばＸ方向に並んで配置される。第１磁気センサ１１と第２磁気センサ１２とは、それぞれ第１流路２１近傍と第２流路２２近傍とにおいて、電流Ｉに基づく信号磁場が互いに逆相に分布する領域に配置される（図６参照）。第１及び第２磁気センサ１１，１２は、例えば磁気抵抗素子を含み、１軸成分の磁場を感知する感度軸を有する。各々の磁気センサ１１，１２は、例えば感度軸の方向がＸ方向に適宜、許容誤差の範囲内で平行になるように配置される。磁気センサ１１，１２の構成の詳細については後述する。 In the current sensor 1, the two magnetic sensors 11 and 12 are arranged, for example, in the X direction. The first magnetic sensor 11 and the second magnetic sensor 12 are disposed in regions near the first flow passage 21 and the second flow passage 22, respectively, in which signal magnetic fields based on the current I are distributed in opposite phases to each other ( See Figure 6). The first and second magnetic sensors 11 and 12 each include, for example, a magnetoresistive element, and have a sensitivity axis that senses a magnetic field of a uniaxial component. Each of the magnetic sensors 11 and 12 is disposed, for example, so that the direction of the sensitivity axis is parallel to the X direction as appropriate within the range of tolerance. Details of the configuration of the magnetic sensors 11 and 12 will be described later.
　第１磁気センサ１１は、磁電変換のためのセンサゲインを有する（以下「Ｇ１」とする）。第１磁気センサ１１は、センサゲインＧ１に従って磁場の感知結果を示す第１センサ信号Ｓ１を生成する。第１磁気センサ１１のセンサゲインＧ１は、本実施形態における第１のセンサゲインの一例である。 The first magnetic sensor 11 has a sensor gain for magnetoelectric conversion (hereinafter referred to as “G1”). The first magnetic sensor 11 generates a first sensor signal S1 indicating the sensing result of the magnetic field according to the sensor gain G1. The sensor gain G1 of the first magnetic sensor 11 is an example of a first sensor gain in the present embodiment.
　また、第２磁気センサ１２は、磁電変換のためのセンサゲインを有する（以下「Ｇ２」とする）。第２磁気センサ１２は、センサゲインＧ２に従って磁場の感知結果を示す第２センサ信号Ｓ２を生成する。第２磁気センサ１２のセンサゲインＧ２は、本実施形態における第２のセンサゲインの一例である。 Further, the second magnetic sensor 12 has a sensor gain for magnetoelectric conversion (hereinafter referred to as "G2"). The second magnetic sensor 12 generates a second sensor signal S2 indicating the sensing result of the magnetic field according to the sensor gain G2. The sensor gain G2 of the second magnetic sensor 12 is an example of a second sensor gain in the present embodiment.
　演算装置３は、図２に示すように、第１演算部３１と、第２演算部３２と、第３演算部３３と、温度検出部３４と、調整部４とを備える。演算装置３は、本実施形態における電流センサ１の出力部の一例である。演算装置３の構成の詳細については後述する。 As shown in FIG. 2, the arithmetic unit 3 includes a first arithmetic unit 31, a second arithmetic unit 32, a third arithmetic unit 33, a temperature detection unit 34, and an adjustment unit 4. The arithmetic device 3 is an example of an output unit of the current sensor 1 in the present embodiment. Details of the configuration of the arithmetic device 3 will be described later.
　第１演算部３１は、例えば１倍以上の倍率を示す演算ゲインを有する（以下「Ａ１」とする）。第１演算部３１は、第１磁気センサ１１から第１センサ信号Ｓ１を入力し、入力した第１センサ信号Ｓ１に演算ゲインＡ１を乗算する。第１センサ信号Ｓ１は、第１演算部３１による乗算を介して、第１検出信号Ｓｐ１として第３演算部３３に出力される。第１演算部３１と第１磁気センサ１１とは、第１検出信号Ｓｐ１を生成する磁気検出部１０Ａを構成する。第１演算部３１の演算ゲインＡ１は、本実施形態における第１の演算ゲインの一例である。 The first operation unit 31 has an operation gain that indicates, for example, a magnification of 1 or more (hereinafter referred to as “A1”). The first computing unit 31 receives the first sensor signal S1 from the first magnetic sensor 11, and multiplies the received first sensor signal S1 by the computing gain A1. The first sensor signal S1 is output to the third arithmetic unit 33 as a first detection signal Sp1 through multiplication by the first arithmetic unit 31. The first arithmetic unit 31 and the first magnetic sensor 11 constitute a magnetic detection unit 10A that generates a first detection signal Sp1. The operation gain A1 of the first operation unit 31 is an example of a first operation gain in the present embodiment.
　第２演算部３２は、例えば１倍以上の倍率を示す演算ゲインを有する（以下「Ａ２」とする）。第２演算部３２は、第２磁気センサ１２から第２センサ信号Ｓ２を入力し、入力した第２センサ信号Ｓ２に演算ゲインＡ２を乗算する。第２センサ信号Ｓ２は、第２演算部３２による乗算を介して、第２検出信号Ｓｐ２として第３演算部３３に出力される。第２演算部３２と第２磁気センサ１２とは、第２検出信号Ｓｐ２を生成する磁気検出部１０Ｂを構成する。第２演算部３２の演算ゲインＡ２は、本実施形態における第２の演算ゲインの一例である。 The second operation unit 32 has an operation gain that indicates, for example, a magnification of 1 or more (hereinafter referred to as “A2”). The second operation unit 32 receives the second sensor signal S2 from the second magnetic sensor 12, and multiplies the input second sensor signal S2 by the operation gain A2. The second sensor signal S2 is output to the third arithmetic unit 33 as a second detection signal Sp2 through multiplication by the second arithmetic unit 32. The second arithmetic unit 32 and the second magnetic sensor 12 constitute a magnetic detection unit 10B that generates a second detection signal Sp2. The operation gain A2 of the second operation unit 32 is an example of a second operation gain in the present embodiment.
　第３演算部３３は、例えば１倍以上の倍率を示す演算ゲインを有する。第３演算部３３は、固有の演算ゲインにおいて、第１演算部３１からの第１検出信号Ｓｐ１と第２演算部３２からの第２検出信号Ｓｐ２との差動増幅を演算して、演算結果を示す出力信号Ｓｏｕｔを生成する。第３演算部３３は、電流センサ１による電流Ｉの検出結果として、出力信号Ｓｏｕｔを出力する。 The third calculation unit 33 has, for example, a calculation gain indicating a magnification of 1 or more. The third calculation unit 33 calculates differential amplification between the first detection signal Sp1 from the first calculation unit 31 and the second detection signal Sp2 from the second calculation unit 32 in the unique calculation gain, and the calculation result To generate an output signal Sout. The third calculation unit 33 outputs an output signal Sout as a detection result of the current I by the current sensor 1.
　また、本実施形態において、第３演算部３３は、温度補償回路等を含む。第３演算部３３は、温度検出部３４による検出結果の温度に応じて、演算ゲイン等の変動を補正するように、出力信号Ｓｏｕｔの温度補償を行う。 Further, in the present embodiment, the third calculation unit 33 includes a temperature compensation circuit and the like. The third calculation unit 33 performs temperature compensation of the output signal Sout so as to correct the fluctuation of the calculation gain or the like according to the temperature detected by the temperature detection unit 34.
　温度検出部３４は、例えば半導体温度センサであり、周囲の温度を検出する。温度検出部３４の種類は特に限定されず、例えば、サーミスタ、熱電対、リニア正温度係数抵抗器、白金測温抵抗体などが用いられてもよい。また、温度検出部３４は、第３演算部３３の温度補償回路に組み込まれてもよい。 The temperature detection unit 34 is, for example, a semiconductor temperature sensor, and detects the ambient temperature. The type of the temperature detection unit 34 is not particularly limited, and, for example, a thermistor, a thermocouple, a linear positive temperature coefficient resistor, a platinum temperature measuring resistor, or the like may be used. Further, the temperature detection unit 34 may be incorporated in the temperature compensation circuit of the third calculation unit 33.
　調整部４は、電流センサ１における種々のゲインを調整する機能を実現するための回路等である。本実施形態において、調整部４は、第１演算部３１の演算ゲインＡ１及び／又は第２演算部３２の演算ゲインＡ２を調整する。調整部４は、演算装置３に組み込まれていてもよいし、演算装置３とは別途、構成されてもよい。 The adjustment unit 4 is a circuit or the like for realizing a function of adjusting various gains in the current sensor 1. In the present embodiment, the adjustment unit 4 adjusts the operation gain A1 of the first operation unit 31 and / or the operation gain A2 of the second operation unit 32. The adjustment unit 4 may be incorporated in the arithmetic device 3 or may be configured separately from the arithmetic device 3.
　本実施形態では、調整部４による調整機能によって、電流センサ１における外部磁場耐性を確保する（詳細は後述）。調整部４による調整機能は、アナログ領域において実現されてもよいし、デジタル領域において実現されてもよい。 In the present embodiment, the external magnetic field resistance in the current sensor 1 is secured by the adjustment function of the adjustment unit 4 (details will be described later). The adjustment function by the adjustment unit 4 may be realized in the analog domain or in the digital domain.
　演算装置３において、第１～第３演算部３１～３３は、バッファとして機能してもよい。また、本実施形態において、各演算部３１～３３は、各々のオフセットを調整するオフセット調整回路を含み得る。オフセットは、各演算部３１～３３が、入力される信号がない状態で出力する信号の値についての基準値からのずれを示す。例えば、第３演算部３３は、出力信号Ｓｏｕｔにおけるオフセットの温度補償を行ってもよい。 In the arithmetic device 3, the first to third arithmetic units 31 to 33 may function as a buffer. Further, in the present embodiment, each of the calculation units 31 to 33 may include an offset adjustment circuit that adjusts each offset. The offset indicates the deviation from the reference value of the value of the signal output from each of the calculation units 31 to 33 in the absence of the input signal. For example, the third operation unit 33 may perform temperature compensation of the offset in the output signal Sout.
　また、２つの磁気センサ１１，１２と演算装置３とは、図２に示すような電流センサ１において、例えば同一のパッケージ内に配置される。２つの磁気センサ１１，１２は、例えば１つの集積チップ内に配置される。２つの磁気センサ１１，１２を同一チップ内で近接配置することにより、外部磁場が空間的に不均一な場合における外部磁場耐性を向上できる。さらに、電流センサ１の周囲温度に勾配が合った場合において、磁気センサｌ１、ｌ２間の温度に対する磁電変換利得ばらつきを抑制でき、外部磁場耐性を向上できる。 The two magnetic sensors 11 and 12 and the arithmetic unit 3 are disposed, for example, in the same package in the current sensor 1 as shown in FIG. The two magnetic sensors 11, 12 are arranged, for example, in one integrated chip. By closely arranging the two magnetic sensors 11 and 12 in the same chip, it is possible to improve the external magnetic field resistance in the case where the external magnetic field is spatially nonuniform. Furthermore, when the ambient temperature of the current sensor 1 has a gradient, variations in magnetoelectric conversion gain with respect to the temperature between the magnetic sensors l1 and l2 can be suppressed, and the external magnetic field resistance can be improved.
　第１及び第２演算部３１，３２は、例えば、電流センサ１内部で同一の集積チップ内に近接配置される。これにより、電流センサ１の周囲温度に勾配があった場合において、第１及び第２演算部３１，３２間の温度に対するゲインばらつきを抑制でき、外部磁場耐性を向上できる。 The first and second calculation units 31, 32 are, for example, closely arranged in the same integrated chip inside the current sensor 1. Thereby, when there is a gradient in the ambient temperature of the current sensor 1, it is possible to suppress the gain variation with respect to the temperature between the first and second calculation units 31, 32, and improve the external magnetic field resistance.
　磁気センサ１１，１２と演算装置３との間にループ配線がある場合、交流の外部磁場が鎖交して起電力を発生することにより、電流の検出誤差を招くことが想定される。これに対して、上述のように第１及び第２演算部３１，３２のばらつきを抑制することで、起電力の同相成分を第３演算部３３において打ち消すことができ、電流センサ１における交流の外部磁場耐性を向上できる。 When there is a loop wiring between the magnetic sensors 11 and 12 and the arithmetic device 3, it is assumed that an AC external magnetic field interlinks to generate an electromotive force, thereby causing a detection error of the current. On the other hand, the in-phase component of the electromotive force can be canceled in the third operation unit 33 by suppressing the variation of the first and second operation units 31 and 32 as described above. The external magnetic field resistance can be improved.
　また、２つの磁気センサ１１，１２と演算装置３とは、図２に示すような電流センサ１において、例えば、ループ配線が生じないように最短に配線される。これにより、交流の外部磁場耐性を向上でき、電流センサ１の検出精度を良くすることができる。 Further, in the current sensor 1 as shown in FIG. 2, for example, the two magnetic sensors 11 and 12 and the arithmetic unit 3 are wired in the shortest length so that no loop wiring occurs. Thereby, the resistance to the external magnetic field of alternating current can be improved, and the detection accuracy of the current sensor 1 can be improved.
１－１．磁気センサについて
　電流センサ１における磁気センサ１１，１２の構成の詳細について、図３を用いて説明する。２つの磁気センサ１１，１２は同様に構成される。以下では、一方の磁気センサ１１について説明する。図３は、電流センサ１における磁気センサ１１の構成を例示する回路図である。 1-1. Magnetic Sensor Details of the configuration of the magnetic sensors 11 and 12 in the current sensor 1 will be described with reference to FIG. The two magnetic sensors 11, 12 are similarly configured. Below, one magnetic sensor 11 is demonstrated. FIG. 3 is a circuit diagram illustrating the configuration of the magnetic sensor 11 in the current sensor 1.
　図３の例において、磁気センサ１１は、４つの磁気抵抗素子１３ａ～１３ｄを含み、ホイートストンブリッジ回路を構成する。磁気センサ１１は、例えば電源電圧Ｖｄｄにより定電圧駆動される。それぞれの磁気抵抗素子１３ａ～１３ｄは、例えばＡＭＲ(Anisotropic Magneto Resistance)素子である。 In the example of FIG. 3, the magnetic sensor 11 includes four magnetoresistive elements 13a to 13d, and constitutes a Wheatstone bridge circuit. The magnetic sensor 11 is driven at a constant voltage, for example, by the power supply voltage Vdd. Each of the magnetoresistive elements 13a to 13d is, for example, an AMR (Anisotropic Magneto Resistance) element.
　本例において、４つの磁気抵抗素子１３ａ～１３ｄのうちの第１及び第２磁気抵抗素子１３ａ，１３ｂの直列回路と、第３及び第４磁気抵抗素子１３ｃ，１３ｄの直列回路とが並列に接続される。第１及び第４磁気抵抗素子１３ａ，１３ｄは、磁気センサ１１に入力される磁場に対して増減傾向が共通する磁気抵抗値ＭＲ１，ＭＲ４を有する。第２及び第３磁気抵抗素子１３ｂ，１３ｃは、第１及び第４磁気抵抗素子１３ａ，１３ｄの磁気抵抗値ＭＲ１，ＭＲ４とは逆の増減傾向の磁気抵抗値ＭＲ２，ＭＲ３を有する。 In this example, the series circuit of the first and second magnetoresistance elements 13a and 13b of the four magnetoresistance elements 13a to 13d and the series circuit of the third and fourth magnetoresistance elements 13c and 13d are connected in parallel. Be done. The first and fourth magnetoresistance elements 13a and 13d have magnetoresistance values MR1 and MR4 that have a common tendency to increase and decrease with respect to the magnetic field input to the magnetic sensor 11. The second and third magnetoresistive elements 13b and 13c have magnetoresistive values MR2 and MR3 having increasing / decreasing tendencies opposite to the magnetoresistive values MR1 and MR4 of the first and fourth magnetoresistive elements 13a and 13d.
　磁気センサ１１の電源電圧Ｖｄｄは、第１及び第３磁気抵抗素子１３ａ，１３ｃ間の接続点に供給される。第２及び第４磁気抵抗素子１３ｂ，１３ｄ間の接続点は接地される。第１及び第２磁気抵抗素子１３ａ，１３ｂ間のノード１４ｐは、電位Ｓ１ｐを有する。第３及び第４磁気抵抗素子１３ｃ，１３ｄ間のノード１４ｍは、電位Ｓ１ｍを有する。各ノード１４ｐ，１４ｍの電位Ｓ１ｐ，Ｓ１ｍは、例えばＶｄｄ／２を中点電位として変動する。本例において、磁気センサ１１は、２つの電位Ｓ１ｐ，Ｓ１ｍによる差動信号として、センサ信号Ｓ１を生成する。 The power supply voltage Vdd of the magnetic sensor 11 is supplied to the connection point between the first and third magnetoresistive elements 13a and 13c. The connection point between the second and fourth magnetoresistive elements 13b and 13d is grounded. A node 14p between the first and second magnetoresistance elements 13a and 13b has a potential S1p. A node 14m between the third and fourth magnetoresistive elements 13c and 13d has a potential S1m. The potentials S1p and S1m of the respective nodes 14p and 14m fluctuate with, for example, Vdd / 2 as the middle point potential. In the present example, the magnetic sensor 11 generates a sensor signal S1 as a differential signal based on the two potentials S1p and S1m.
　以上の磁気センサ１１の構成は一例であり、特にこれに限定されない。例えば、磁気センサ１１は、ハーフブリッジ回路で構成されてもよく、シングルエンドでセンサ信号Ｓ１を生成してもよい。また、磁気抵抗素子１３ａ～１３ｄはＡＭＲ素子に限らず、例えばＧＭＲ(Giant Magneto Resistance)、ＴＭＲ(Tunnel Magneto Resistance)、ＢＭＲ(Balistic Magneto Resistance)、ＣＭＲ(Colossal Magneto Resistance)等の種々のＭＲ素子であってもよい。 The configuration of the magnetic sensor 11 described above is an example, and the present invention is not particularly limited thereto. For example, the magnetic sensor 11 may be configured by a half bridge circuit, and may generate the sensor signal S1 at a single end. The magnetoresistive elements 13a to 13d are not limited to AMR elements, but various MR elements such as GMR (Giant Magneto Resistance), TMR (Tunnel Magneto Resistance), BMR (Balistic Magneto Resistance), CMR (Colossal Magneto Resistance), etc. It may be.
　また、磁気センサ１１，１２として、ホール素子を有する磁気素子、磁気インピーダンス効果を利用するＭＩ(Magneto Impedance)素子を有する磁気素子又はフラックスゲート型磁気素子などが用いられてもよい。また、磁気センサ１１，１２の駆動方法としては、定電流駆動、パルス駆動などが採用されてもよい。 In addition, as the magnetic sensors 11 and 12, a magnetic element having a Hall element, a magnetic element having a MI (Magneto Impedance) element using a magnetic impedance effect, a flux gate type magnetic element, or the like may be used. In addition, as a method of driving the magnetic sensors 11, 12, constant current driving, pulse driving, or the like may be employed.
１－２．演算装置について
　電流センサ１における演算装置３の構成の詳細について、図４，５を用いて説明する。図４は、実施形態１における調整部４と第１演算部３１の構成例を示す図である。図５は、第３演算部３３の構成例を示す図である。 1-2. Arithmetic Device Details of the configuration of the arithmetic device 3 in the current sensor 1 will be described with reference to FIGS. FIG. 4 is a view showing a configuration example of the adjustment unit 4 and the first calculation unit 31 in the first embodiment. FIG. 5 is a view showing a configuration example of the third calculation unit 33. As shown in FIG.
　電流センサ１の演算装置３においては、各部３１～３３，４に種々の構成を採用することができる。例えば、調整部４は、電流センサ１の製造出荷時等に、レーザトリム、ツェナーザッピング、抵抗リンク、ＥＥＰＲＯＭトリム、デジタルトリムなどを適用可能な各種回路を含んでもよい。以下では、調整部４が第１演算部３１を調整対象とする例を説明する。第２演算部３２は、第１演算部３１と同様に構成することができる。 In the arithmetic unit 3 of the current sensor 1, various configurations can be adopted for each of the units 31 to 33 and 4. For example, the adjustment unit 4 may include various circuits to which laser trim, zener zapping, resistive link, EEPROM trim, digital trim, etc. can be applied when the current sensor 1 is manufactured and shipped. Hereinafter, an example in which the adjustment unit 4 sets the first calculation unit 31 as an adjustment target will be described. The second operation unit 32 can be configured in the same manner as the first operation unit 31.
　図４（ａ），（ｂ），（ｃ）は、それぞれ調整部４及び第１演算部３１についての第１、第２及び第３の構成例を示す。図４（ａ）に示す第１の構成例は、調整部４がアナログ領域において演算ゲインＡ１を調整する例である。図４（ｂ）に示す第２の構成例と、図４（ｃ）に示す第３の構成例とは、それぞれ調整部４がデジタル領域において演算ゲインＡ１を調整する例である。 FIGS. 4A, 4B, and 4C show first, second, and third configuration examples of the adjustment unit 4 and the first calculation unit 31, respectively. The first configuration example shown in FIG. 4A is an example in which the adjustment unit 4 adjusts the operation gain A1 in the analog domain. The second configuration example shown in FIG. 4B and the third configuration example shown in FIG. 4C are examples in which the adjustment unit 4 adjusts the calculation gain A1 in the digital domain.
　第１の構成例において、第１演算部３１は、図４（ａ）に示すように増幅器５０を備える。本構成例において、調整部４は、増幅器５０のゲインすなわち演算ゲインＡ１を規定する抵抗４０などを含み、抵抗４０の抵抗値Ｒを調整する。増幅器５０は、シングルエンドの入力端子を有してもよいし、差動の入力端子を有してもよい。また、増幅器は、シングルエンドの出力端子を有してもよいし、差動の出力端子を有してもよい。増幅器５０は、バッファアンプであってもよい。 In the first configuration example, the first operation unit 31 includes an amplifier 50 as shown in FIG. 4 (a). In the present configuration example, the adjustment unit 4 includes the resistor 40 or the like that defines the gain of the amplifier 50, that is, the operation gain A1, and adjusts the resistance value R of the resistor 40. The amplifier 50 may have a single-ended input terminal or a differential input terminal. Also, the amplifier may have a single-ended output terminal or a differential output terminal. The amplifier 50 may be a buffer amplifier.
　第２の構成例において、第１演算部３１は、図４（ｂ）に示すように、増幅器５０と、Ａ／Ｄ（アナログ／デジタル）変換器５１と、デジタル処理部５２とを備える。本構成例において、調整部４は、例えば、フラッシュメモリ等の内部メモリ４１を有する。調整部４は、内部メモリに演算ゲインＡ１を規定する値を格納する。 In the second configuration example, as shown in FIG. 4B, the first operation unit 31 includes an amplifier 50, an A / D (analog / digital) converter 51, and a digital processing unit 52. In the present configuration example, the adjustment unit 4 includes, for example, an internal memory 41 such as a flash memory. The adjustment unit 4 stores a value defining the operation gain A1 in the internal memory.
　図４（ｂ）の構成例において、第１演算部３１のＡ／Ｄ変換器５１は、増幅器５０を介して入力するセンサ信号Ｓ１をＡ／Ｄ変換する。デジタル処理部５２は、例えば調整部４の内部メモリ４１に格納された値を参照し、Ａ／Ｄ変換された信号に演算処理を行って、演算結果を第１検出信号Ｓｐ１として出力する。 In the configuration example of FIG. 4B, the A / D converter 51 of the first operation unit 31 A / D converts the sensor signal S1 input via the amplifier 50. The digital processing unit 52 refers to, for example, the value stored in the internal memory 41 of the adjustment unit 4, performs arithmetic processing on the A / D converted signal, and outputs the calculation result as a first detection signal Sp1.
　第３の構成例において、第１演算部３１は、図４（ｂ）の構成に加えて、図４（ｂ）に示すように、Ｄ／Ａ（デジタル／アナログ）変換器５３をさらに備える。本構成例の第１演算部３１において、Ｄ／Ａ変換器５３は、デジタル処理部５２の演算処理結果にＤ／Ａ変換を行って、変換結果を第１検出信号Ｓｐ１として出力する。Ｄ／Ａ変換器５３は、シングルエンドの出力端子を有してもよいし、差動の出力端子を有してもよい。 In the third configuration example, the first calculation unit 31 further includes a D / A (digital / analog) converter 53 as shown in FIG. 4B in addition to the configuration of FIG. 4B. In the first operation unit 31 of this configuration example, the D / A converter 53 performs D / A conversion on the operation processing result of the digital processing unit 52, and outputs the conversion result as a first detection signal Sp1. The D / A converter 53 may have a single-ended output terminal or may have a differential output terminal.
　以上のような各種構成において、調整部４は、上述した各種手法等を適用して、例えば演算ゲインＡ１を０．１％以下の分解能で調整する。これにより、電流センサ１における外部磁場耐性を精度良く確保することができる。調整部４は、上記の構成例と同様に、第２演算部３２の調整を行ってもよい。調整部４は、第１及び第２演算部３１，３２の双方を調整可能に構成されてもよいし、一方のみ調整可能に構成されてもよい。 In the various configurations as described above, the adjustment unit 4 adjusts, for example, the calculation gain A1 with a resolution of 0.1% or less by applying the various methods described above. Thereby, the external magnetic field tolerance in the current sensor 1 can be secured with high accuracy. The adjustment unit 4 may perform adjustment of the second calculation unit 32 as in the above configuration example. The adjustment unit 4 may be configured to be able to adjust both of the first and second calculation units 31 and 32, or may be configured to be able to adjust only one of them.
　演算装置３の第３演算部３３についても、種々の構成を採用可能である。第３演算部３３の各種構成例を図５（ａ）～（ｇ）に示す。図５（ａ），（ｂ），（ｃ）に示す構成例は、それぞれ第３演算部３３がアナログ入力で且つアナログ出力で構成される例である。 Various configurations can also be adopted for the third arithmetic unit 33 of the arithmetic unit 3. Various configuration examples of the third arithmetic unit 33 are shown in FIGS. 5 (a) to 5 (g). The configuration examples shown in FIGS. 5 (a), 5 (b) and 5 (c) are examples in which the third operation unit 33 is an analog input and an analog output, respectively.
　例えば、図５（ａ）に示すように、第３演算部３３は、差動増幅器６０を備えてもよい。この場合、第３演算部３３における温度補償は、差動増幅器６０のゲインおよびオフセットを調整することによって、アナログ領域で行われてもよい。差動増幅器６０は、シングルエンドの出力端子を有してもよいし、差動の出力端子を有してもよい。 For example, as shown in FIG. 5A, the third operation unit 33 may include a differential amplifier 60. In this case, temperature compensation in the third operation unit 33 may be performed in the analog domain by adjusting the gain and offset of the differential amplifier 60. The differential amplifier 60 may have a single-ended output terminal or may have a differential output terminal.
　また、第３演算部３３は、図５（ｂ）に示すように、差動増幅器６０に加えて、Ａ／Ｄ変換器６１と、デジタル処理部６２と、Ｄ／Ａ変換器６３とを備えてもよい。Ｄ／Ａ変換器６３は、シングルエンドの出力端子を有してもよいし、差動の出力端子を有してもよい。Ｄ／Ａ変換器６３の出力側に、バッファアンプ等が設けられてもよい。 In addition to the differential amplifier 60, the third operation unit 33 includes an A / D converter 61, a digital processing unit 62, and a D / A converter 63, as shown in FIG. 5 (b). May be The D / A converter 63 may have a single-ended output terminal or may have a differential output terminal. A buffer amplifier or the like may be provided on the output side of the D / A converter 63.
　第３演算部３３における温度補償は、図５（ｂ）のデジタル処理部６２等において、デジタル領域で行われてもよい。また、第３演算部３３においては、図５（ｃ）に示すように、図５（ｂ）の構成例から差動増幅器６０が省略されてもよい。この場合、Ａ／Ｄ変換器６１は差動入力する。 The temperature compensation in the third operation unit 33 may be performed in the digital region in the digital processing unit 62 or the like of FIG. 5 (b). Further, in the third operation unit 33, as shown in FIG. 5C, the differential amplifier 60 may be omitted from the configuration example of FIG. 5B. In this case, the A / D converter 61 is differentially input.
　また、第３演算部３３は、デジタル出力で構成されてもよい。例えば図５（ｄ）に示すように、第３演算部３３は、図５（ｂ）の構成例からＤ／Ａ変換器６３を省略して構成されてもよい。また、図５（ｅ）に示すように、図５（ｃ）の構成例からＤ／Ａ変換器６３が省略されてもよい。 In addition, the third arithmetic unit 33 may be configured by digital output. For example, as shown in FIG. 5 (d), the third operation unit 33 may be configured by omitting the D / A converter 63 from the configuration example of FIG. 5 (b). Further, as shown in FIG. 5 (e), the D / A converter 63 may be omitted from the configuration example of FIG. 5 (c).
　また、第３演算部３３は、デジタル入力で構成されてもよい。例えば、図５（ｆ）に示すように、第３演算部３３は、図５（ｃ）の構成例からＡ／Ｄ変換器６１を省略して構成されてもよい。また、第３演算部３３は、図５（ｇ）に示すように、デジタル処理部６２を備え、デジタル入力で且つデジタル出力で構成されてもよい。 In addition, the third arithmetic unit 33 may be configured by digital input. For example, as shown in FIG. 5 (f), the third arithmetic unit 33 may be configured by omitting the A / D converter 61 from the configuration example of FIG. 5 (c). Further, as shown in FIG. 5G, the third arithmetic unit 33 may include a digital processing unit 62, and may be configured as a digital input and a digital output.
　以上のように構成される第３演算部３３は、例えば電流センサ１の製造出荷時に温度補償等の各種調整を行われてもよい。例えば、上記の調整部４と同様に、レーザトリム等の各種手法を適用することにより、第３演算部３３が調整されてもよい。第３演算部３３の調整により、電流センサ１の検出精度を向上することができる。 The third calculation unit 33 configured as described above may perform various adjustments such as temperature compensation at the time of manufacture and shipping of the current sensor 1, for example. For example, as in the case of the adjustment unit 4 described above, the third calculation unit 33 may be adjusted by applying various methods such as laser trimming. The adjustment accuracy of the third arithmetic unit 33 can improve the detection accuracy of the current sensor 1.
　また、演算装置３は、電流センサ１の各種機能を実現するための各種半導体集積回路等を含んでもよい。例えば、演算装置３は、所定の機能を実現するように設計された専用の電子回路や再構成可能な電子回路などのハードウェア回路を含んでもよい。また、演算装置３は、例えばソフトウェアと協働して所定の機能を実現するＣＰＵ等を含んでもよい。演算装置３は、フラッシュメモリ等の内部メモリを含んでもよく、内部メモリに各種データ及びプログラム等を格納してもよい。演算装置３は、ＣＰＵ、ＭＰＵ、マイコン、ＤＳＰ、ＦＰＧＡ、ＡＳＩＣ等の種々の半導体集積回路で構成されてもよい。 The arithmetic device 3 may also include various semiconductor integrated circuits and the like for realizing various functions of the current sensor 1. For example, the arithmetic unit 3 may include hardware circuits such as dedicated electronic circuits or reconfigurable electronic circuits designed to realize a predetermined function. In addition, the arithmetic device 3 may include, for example, a CPU or the like that realizes a predetermined function in cooperation with software. Arithmetic unit 3 may include an internal memory such as a flash memory, and may store various data and programs in the internal memory. The arithmetic unit 3 may be configured by various semiconductor integrated circuits such as a CPU, an MPU, a microcomputer, a DSP, an FPGA, and an ASIC.
２．動作
　以上のように構成される電流センサ１の動作について、以下説明する。 2. Operation The operation of the current sensor 1 configured as described above will be described below.
　本実施形態に係る電流センサ１の基本的な動作について、図６を用いて説明する。図６は、電流センサ１における信号磁場Ｂ１，Ｂ２と磁気センサ１１，１２との関係を説明するための図である。図６は、図１のＡ－Ａ’断面近傍における各流路２１，２２及び各磁気センサ１１，１２を示している。 The basic operation of the current sensor 1 according to the present embodiment will be described with reference to FIG. FIG. 6 is a diagram for explaining the relationship between the signal magnetic fields B1 and B2 and the magnetic sensors 11 and 12 in the current sensor 1. FIG. 6 shows the flow paths 21 and 22 and the magnetic sensors 11 and 12 in the vicinity of the A-A ′ cross section of FIG.
　図６では、検出対象の電流がバスバー２を＋Ｙ向きに流れた際に（図１参照）、第１流路２１近傍に生じる信号磁場Ｂ１と、第２流路２２近傍に生じる信号磁場Ｂ２とを例示している。バスバー２においては、電流が分流して第１流路２１と第２流路２２とに流れる。これにより、図６に示すように、第１流路２１近傍の信号磁場Ｂ１は第１流路２１の周囲を周回し、第２流路２２近傍の信号磁場Ｂ２は第２流路２２の周囲を周回する。 6, when the current to be detected flows through the bus bar 2 in the + Y direction (see FIG. 1), a signal magnetic field B1 generated in the vicinity of the first flow path 21 and a signal magnetic field B2 generated in the vicinity of the second flow path 22 Is illustrated. In the bus bar 2, the current is divided and flows to the first flow path 21 and the second flow path 22. Thereby, as shown in FIG. 6, the signal magnetic field B1 in the vicinity of the first flow path 21 circulates around the first flow path 21, and the signal magnetic field B2 in the vicinity of the second flow path 22 is the periphery of the second flow path 22. Go around.
　本実施形態に係る電流センサ１では、第１流路２１と第２流路２２とにおいて電流が同じ向き（例えば＋Ｙ向き）に流れるため、第１流路２１近傍の信号磁場Ｂ１と第２流路２２近傍の信号磁場Ｂ２とは、同じ周回方向を有する（例えば時計回り）。このことから、図６に示すように、第１及び第２流路２１，２２間における第１流路２１近傍の領域Ｒ１と第２流路２２近傍の領域Ｒ２とにおいて、それぞれを通過する信号磁場Ｂ１，Ｂ２のＸ成分が、互いに逆向きになる。 In the current sensor 1 according to the present embodiment, the current flows in the same direction (for example, + Y direction) in the first flow path 21 and the second flow path 22. Therefore, the signal magnetic field B1 and the second flow near the first flow path 21 The signal magnetic field B2 in the vicinity of the path 22 has the same winding direction (for example, clockwise). From this, as shown in FIG. 6, in the region R1 in the vicinity of the first channel 21 and the region R2 in the vicinity of the second channel 22 between the first and second channels 21 and 22, signals passing respectively are The X components of the magnetic fields B1 and B2 are opposite to each other.
　そこで、本実施形態の電流センサ１では、上記のような第１流路２１近傍の領域Ｒ１に一方の磁気センサ１１が配置され、他方の磁気センサ１２が第２流路２２近傍の領域Ｒ２に配置される。これにより、２つの磁気センサ１１，１２には、互いに逆相の信号磁場Ｂ１，Ｂ２が入力されることとなる。 Therefore, in the current sensor 1 of the present embodiment, one magnetic sensor 11 is disposed in the region R1 near the first flow passage 21 as described above, and the other magnetic sensor 12 is in the region R2 near the second flow passage 22. Be placed. As a result, the signal magnetic fields B1 and B2 having opposite phases to each other are input to the two magnetic sensors 11 and 12, respectively.
　第１磁気センサ１１は、第１流路２１近傍の信号磁場Ｂ１の検出結果として、入力された磁場に応じた第１センサ信号Ｓ１を生成する（図２参照）。第２磁気センサ１２は、第２流路２２近傍の信号磁場Ｂ２の検出結果として、入力された磁場に応じた第２センサ信号Ｓ２を生成する。 The first magnetic sensor 11 generates a first sensor signal S1 according to the input magnetic field as a detection result of the signal magnetic field B1 near the first flow path 21 (see FIG. 2). The second magnetic sensor 12 generates a second sensor signal S2 according to the input magnetic field as a detection result of the signal magnetic field B2 in the vicinity of the second flow path 22.
　ここで、各磁気センサ１１，１２に入力される磁場には、信号磁場Ｂ１，Ｂ２だけでなく、外乱磁場のようなノイズも含まれることが想定される。このようなノイズは、２つの磁気センサ１１，１２の配置位置を近接させることにより、各磁気センサ１１，１２に対して、同相（同じ向きで且つ同程度の大きさ）で入力されると考えられる。 Here, it is assumed that the magnetic fields input to the magnetic sensors 11 and 12 include not only the signal magnetic fields B1 and B2, but also noise such as a disturbance magnetic field. Such noise is considered to be input to each of the magnetic sensors 11 and 12 in the same phase (in the same direction and with the same magnitude) by bringing the arrangement positions of the two magnetic sensors 11 and 12 close to each other. Be
　そこで、本実施形態に係る電流センサ１においては、演算装置３が、２つの磁気センサ１１，１２の感知結果の差動増幅を演算して、電流の検出結果を示す出力信号Ｓｏｕｔを算出する。これにより、それぞれの磁気センサ１１，１２の感知結果に同相で含まれ得るノイズを相殺して、信号磁場Ｂ１，Ｂ２に基づく電流の検出精度を良くすることができる。 Therefore, in the current sensor 1 according to the present embodiment, the arithmetic device 3 calculates differential amplification of the sensing results of the two magnetic sensors 11 and 12 to calculate an output signal Sout indicating the detection result of the current. As a result, it is possible to offset the noise that may be included in phase with the sensing results of the respective magnetic sensors 11 and 12 and to improve the detection accuracy of the current based on the signal magnetic fields B1 and B2.
２－１．外部磁場耐性について
　以上のような電流センサ１において、外部磁場によって出力信号Ｓｏｕｔを変動させないようにする外部磁場耐性について、図７，８を用いて説明する。図７は、電流センサ１における外部磁場耐性を説明するための図である。図８は、電流センサ１における各種信号に対する外部磁場の影響を例示するグラフである。 2-1. Regarding the External Magnetic Field Resistance The external magnetic field resistance for preventing the output signal Sout from fluctuating by the external magnetic field in the current sensor 1 as described above will be described with reference to FIGS. FIG. 7 is a diagram for explaining the external magnetic field resistance in the current sensor 1. FIG. 8 is a graph illustrating the influence of the external magnetic field on various signals in the current sensor 1.
　図７では、図６と同様の断面近傍の各流路２１，２２及び各磁気センサ１１，１２において、想定される外部磁場の一例として同相磁場Ｂｃが印加される様子を示している。同相磁場Ｂｃは、上述の信号磁場Ｂ１，Ｂ２（図６）とは異なり、第１磁気センサ１１と第２磁気センサ１２とに同相で入力される磁場である。 FIG. 7 shows a state in which the in-phase magnetic field Bc is applied as an example of the assumed external magnetic field in the flow paths 21 and 22 and the magnetic sensors 11 and 12 near the cross section similar to FIG. The in-phase magnetic field Bc is a magnetic field that is input to the first magnetic sensor 11 and the second magnetic sensor 12 in phase unlike the above-described signal magnetic fields B1 and B2 (FIG. 6).
　電流センサ１の使用時には、例えば電流センサ１が取り付けられたバスバー２とは別の隣接するバスバー等からの磁場や、地磁気、鉄塔から発生する磁場などの種々の外部磁場が想定される。これらの外部磁場は、図７に例示する同相磁場Ｂｃのように、電流センサ１の各磁気センサ１１，１２に入力されることが想定される。図８（ａ）に、同相磁場Ｂｃが入力されたときの各磁気センサ１１，１２の各センサ信号Ｓ１，Ｓ２を例示する。 When the current sensor 1 is used, various external magnetic fields such as a magnetic field from an adjacent bus bar other than the bus bar 2 to which the current sensor 1 is attached, geomagnetic field, a magnetic field generated from a steel tower, etc. are assumed. It is assumed that these external magnetic fields are input to the magnetic sensors 11 and 12 of the current sensor 1 as the in-phase magnetic field Bc illustrated in FIG. 7. FIG. 8A illustrates the sensor signals S1 and S2 of the magnetic sensors 11 and 12 when the in-phase magnetic field Bc is input.
　図８（ａ）は、第１磁気センサ１１のセンサゲインＧ１と、第２磁気センサ１２のセンサゲインＧ２とがずれている場合のセンサ信号Ｓ１，Ｓ２の特性を例示している。電流センサ１における２つの磁気センサ１１，１２のセンサゲインＧ１，Ｇ２には、例えば数パーセント程度の製造ばらつきが在ることが想定される。この場合、図８（ａ）に示すように、同相磁場Ｂｃに応じた２つのセンサ信号Ｓ１，Ｓ２の変動の仕方（グラフの傾き）が、互いに異なることとなる。 FIG. 8A illustrates the characteristics of the sensor signals S1 and S2 when the sensor gain G1 of the first magnetic sensor 11 and the sensor gain G2 of the second magnetic sensor 12 deviate from each other. It is assumed that the sensor gains G1 and G2 of the two magnetic sensors 11 and 12 in the current sensor 1 have manufacturing variations of, for example, about several percent. In this case, as shown in FIG. 8A, the manners (slopes of the graph) of the fluctuation of the two sensor signals S1 and S2 according to the in-phase magnetic field Bc are different from each other.
　図８（ｂ）は、図８（ａ）の各センサ信号Ｓ１，Ｓ２に基づく各検出信号Ｓｐ１’，Ｓｐ２’の一例を示す。図８（ｃ）は、図８（ｂ）の各検出信号Ｓｐ１’，Ｓｐ２’に基づく出力信号Ｓｏｕｔ’を示す。 FIG. 8B shows an example of the detection signals Sp1 'and Sp2' based on the sensor signals S1 and S2 of FIG. 8A. FIG. 8 (c) shows an output signal Sout 'based on the detection signals Sp1' and Sp2 'of FIG. 8 (b).
　図８（ｂ），（ｃ）では、上記のような２つの磁気センサ１１，１２間のばらつきを考慮せずに各検出信号Ｓｐ１’，Ｓｐ２’が生成された場合を例示している。この場合、図８（ｂ）に示すように、同相磁場Ｂｃに応じた２つの検出信号Ｓｐ１’，Ｓｐ２’の変動の仕方が、２つのセンサ信号Ｓ１，Ｓ２と同様に互いに異なっている。このため、２つの検出信号Ｓｐ１’，Ｓｐ２’の差動増幅時に同相磁場Ｂｃの影響が残り、図８（ｃ）に示すように、出力信号Ｓｏｕｔ’が同相磁場Ｂｃに応じて変動してしまう。 FIGS. 8B and 8C illustrate the case where the detection signals Sp1 'and Sp2' are generated without considering the variation between the two magnetic sensors 11 and 12 as described above. In this case, as shown in FIG. 8B, the manners of fluctuation of the two detection signals Sp1 'and Sp2' according to the in-phase magnetic field Bc are different from each other as in the case of the two sensor signals S1 and S2. Therefore, the influence of the in-phase magnetic field Bc remains at the time of differential amplification of the two detection signals Sp1 ′ and Sp2 ′, and the output signal Sout ′ fluctuates according to the in-phase magnetic field Bc as shown in FIG. .
　そこで、本実施形態に係る電流センサ１は、次式（１）を適宜、許容誤差の範囲内で成立させるように、調整部４において第１及び第２演算部３１，３２の演算ゲインＡ１，Ａ２の少なくとも一方を調整する。 Therefore, in the current sensor 1 according to the present embodiment, the operation gains A1 and A1 of the first and second operation units 31 and 32 in the adjustment unit 4 are appropriately set so that the following expression (1) is satisfied within the allowable error range. Adjust at least one of A2.
Ｇ１×Ａ１＝Ｇ２×Ａ２　　　…（１）
　上式（１）によると、２つのセンサゲインＧ１，Ｇ２がばらつく場合においても、電流センサ１において各検出信号Ｓｐ１，Ｓｐ２を生成するための通算のゲイン「Ｇ１×Ａ１」、「Ｇ２×Ａ２」が合致する。これにより、２つの検出信号Ｓｐ１，Ｓｐ２の差動増幅時に同相磁場Ｂｃの様な外部磁場の影響を適切に打ち消して、電流センサ１の外部磁場耐性を確保することができる。以上のような外部磁場耐性を有する電流センサ１の製造方法について、以下説明する。 G1 × A1 = G2 × A2 (1)
According to the above equation (1), even when the two sensor gains G1 and G2 vary, the total gain “G1 × A1” and “G2 × A2” for generating the detection signals Sp1 and Sp2 in the current sensor 1 Matches. Thus, the external magnetic field resistance of the current sensor 1 can be secured by appropriately canceling the influence of the external magnetic field such as the in-phase magnetic field Bc at the time of differential amplification of the two detection signals Sp1 and Sp2. The method of manufacturing the current sensor 1 having the resistance to the external magnetic field as described above will be described below.
２－２．電流センサの製造方法について
　本実施形態に係る電流センサ１の調整部４は、例えば電流センサ１の製造出荷時に、同相磁場Ｂｃを用いて設定される。以下、電流センサ１の製造時にゲイン等を調整する方法について、図９～１３を用いて説明する。図９は、本実施形態に係る電流センサ１の調整方法を示すフローチャートである。 2-2. Regarding Method of Manufacturing Current Sensor The adjustment unit 4 of the current sensor 1 according to the present embodiment is set using, for example, the in-phase magnetic field Bc at the time of manufacture and shipment of the current sensor 1. Hereinafter, a method of adjusting the gain and the like at the time of manufacturing the current sensor 1 will be described with reference to FIGS. FIG. 9 is a flowchart showing a method of adjusting the current sensor 1 according to the present embodiment.
　図９のフローチャートは、電流センサ１の製造出荷時における検査段階等において、出荷前の電流センサ１が準備された状態において開始される。電流センサ１は、上述した基本的な動作が実行可能な状態にまで準備される。本フローチャートにおける各処理は、例えば検査者が所定の制御装置（例えばＰＣ又は各種検査装置）を用いて実施される。 The flow chart of FIG. 9 is started in the state where the current sensor 1 before shipment is prepared in the inspection stage etc. at the time of manufacture shipment of the current sensor 1. The current sensor 1 is prepared to a state in which the basic operation described above can be performed. Each process in this flowchart is performed, for example, by an inspector using a predetermined control device (for example, a PC or various inspection devices).
　図９に示す調整方法においては、調整対象として準備された電流センサ１に、同相磁場Ｂｃを印加する（ＳＴ１）。同相磁場Ｂｃは、例えばヘルムホルツコイルを用いて発生させることができる。同相磁場Ｂｃの発生方法は特に限定されず、例えば電磁石や永久磁石が用いられてもよい。発生させた同相磁場Ｂｃが電流センサ１に印加される様子の一例を、図１０に示す。 In the adjustment method shown in FIG. 9, the in-phase magnetic field Bc is applied to the current sensor 1 prepared as the adjustment target (ST1). The in-phase magnetic field Bc can be generated using, for example, a Helmholtz coil. The method of generating the in-phase magnetic field Bc is not particularly limited, and for example, an electromagnet or a permanent magnet may be used. An example of how the generated in-phase magnetic field Bc is applied to the current sensor 1 is shown in FIG.
　図１０は、電流センサ１がバスバー２に取り付けられた状態において同相磁場Ｂｃが印加される例を示している。図１０の例において、同相磁場Ｂｃは、Ｘ方向に沿って印加され、電流センサ１を含む空間領域において均一な分布を有する。同相磁場Ｂｃは、適宜許容誤差の範囲内で各磁気センサ１１，１２の感度軸の方向に平行に印加されてもよいし、特に感度軸の方向を考慮せずに印加されてもよい。また、同相磁場Ｂｃは、２つの磁気センサ１１，１２を含む範囲内で均一な空間分布を有してもよい。 FIG. 10 shows an example in which the in-phase magnetic field Bc is applied when the current sensor 1 is attached to the bus bar 2. In the example of FIG. 10, the in-phase magnetic field Bc is applied along the X direction, and has a uniform distribution in the space region including the current sensor 1. The in-phase magnetic field Bc may be applied in parallel with the direction of the sensitivity axis of each of the magnetic sensors 11 and 12 as appropriate within the range of tolerance, or may be applied without considering the direction of the sensitivity axis in particular. Also, the in-phase magnetic field Bc may have a uniform spatial distribution within the range including the two magnetic sensors 11 and 12.
　本実施形態では、上記のような同相磁場Ｂｃを用いて、第１演算部３１の演算ゲインＡ１及び第２演算部３２の演算ゲインＡ２の少なくとも一方を調整する（ＳＴ２）。ステップＳＴ２について、図１１（ａ）～（ｃ）を用いて説明する。 In the present embodiment, at least one of the calculation gain A1 of the first calculation unit 31 and the calculation gain A2 of the second calculation unit 32 is adjusted using the in-phase magnetic field Bc as described above (ST2). Step ST2 will be described using FIGS. 11 (a) to 11 (c).
　図１１（ａ）は、未調整の各検出信号Ｓｐ１，Ｓｐ２と同相磁場Ｂｃとの関係を例示するグラフである。図１１（ｂ）は、図１１（ａ）の例からステップＳＴ２の調整後の各検出信号Ｓｐ１，Ｓｐ２と同相磁場Ｂｃとの関係を示すグラフである。図１１（ｃ）は、図１１（ｂ）の状態に対応する出力信号Ｓｏｕｔと同相磁場Ｂｃとの関係を示すグラフである。 FIG. 11A is a graph illustrating the relationship between the unadjusted detection signals Sp1 and Sp2 and the in-phase magnetic field Bc. FIG. 11B is a graph showing the relationship between the detection signals Sp1 and Sp2 and the in-phase magnetic field Bc after adjustment of the example of FIG. 11A to step ST2. FIG.11 (c) is a graph which shows the relationship between the output signal Sout and the in-phase magnetic field Bc corresponding to the state of FIG.11 (b).
　図１１（ａ）は、ステップＳＴ２の調整前において、同相磁場Ｂｃに応じた各検出信号Ｓｐ１，Ｓｐ２の変化量ΔＳｐ１，ΔＳｐ２が、互いに異なった例を示している。変化量ΔＳｐ１，ΔＳｐ２は、各検出信号Ｓｐ１，Ｓｐ２が同相磁場Ｂｃの印加によって、印加されていない状態から変化した信号量を示す。同相磁場Ｂｃと各々の変化量ΔＳｐ１，ΔＳｐ２との間の関係は、次式（２），（３）のように表される。 FIG. 11A shows an example in which the amounts of change ΔSp1 and ΔSp2 of the detection signals Sp1 and Sp2 according to the in-phase magnetic field Bc are different from each other before the adjustment of step ST2. The amounts of change .DELTA.Sp1 and .DELTA.Sp2 indicate the amount of signal that the detection signals Sp1 and Sp2 have changed from the non-applied state by the application of the in-phase magnetic field Bc. The relationship between the in-phase magnetic field Bc and each of the change amounts ΔSp1 and ΔSp2 is expressed by the following equations (2) and (3).
ΔＳｐ１＝Ａ１×Ｇ１×Ｂｃ　　　…（２）
ΔＳｐ２＝Ａ２×Ｇ２×Ｂｃ　　　…（３）
　上式（２）において、同相磁場Ｂｃに対するゲイン「Ａ１×Ｇ１」は、図１１（ａ）では、第１検出信号Ｓｐ１のグラフの傾きに対応する。また、上式（３）におけるゲイン「Ａ２×Ｇ２」は、第１検出信号Ｓｐ２のグラフの傾きに対応する。図１１（ａ）では、式（２）のゲイン「Ａ１×Ｇ１」と式（３）のゲイン「Ａ２×Ｇ２」とがずれていることから、第１及び第２検出信号Ｓｐ１，Ｓｐ２のグラフの傾きが互いに異なっている。 ΔSp1 = A1 × G1 × Bc (2)
ΔSp2 = A2 × G2 × Bc (3)
In the above equation (2), the gain “A1 × G1” for the in-phase magnetic field Bc corresponds to the slope of the graph of the first detection signal Sp1 in FIG. 11 (a). Further, the gain “A2 × G2” in the above equation (3) corresponds to the slope of the graph of the first detection signal Sp2. In FIG. 11A, since the gain “A1 × G1” in equation (2) and the gain “A2 × G2” in equation (3) deviate from each other, the graphs of the first and second detection signals Sp1 and Sp2 The inclinations of are different from each other.
　ステップＳＴ２では、例えば、図１１（ａ），（ｂ）に示すように第１検出信号Ｓｐ１の変化量ΔＳｐ１が第２検出信号Ｓｐ２の変化量ΔＳｐ２に合致するように、調整部４を用いて第１演算部３１の演算ゲインＡ１が調整される。ステップＳＴ２は、第１演算部３１からの第１検出信号Ｓｐ１の変化量ΔＳｐ１と、第２演算部３２からの第２検出信号Ｓｐ２の変化量ΔＳｐ２とを測定することにより行われる。各々の変化量ΔＳｐ１，ΔＳｐ２は、例えば、同相磁場Ｂｃを印加する前後の各検出信号Ｓｐ１，Ｓｐ２の値に基づき測定できる。 In step ST2, for example, as shown in FIGS. 11A and 11B, the adjustment unit 4 is used so that the change amount ΔSp1 of the first detection signal Sp1 matches the change amount ΔSp2 of the second detection signal Sp2. The calculation gain A1 of the first calculation unit 31 is adjusted. Step ST2 is performed by measuring the change amount ΔSp1 of the first detection signal Sp1 from the first calculation unit 31 and the change amount ΔSp2 of the second detection signal Sp2 from the second calculation unit 32. The variation amounts ΔSp1 and ΔSp2 can be measured, for example, based on the values of the detection signals Sp1 and Sp2 before and after applying the in-phase magnetic field Bc.
　ステップＳＴ２において、変化量ΔＳｐ１，ΔＳｐ２間の合致は、適宜、許容誤差の範囲内で行える。許容誤差は、例えば±０．１％である。例えば、各々の変化量ΔＳｐ１，ΔＳｐ２をモニタしながら演算ゲインＡ１を徐々に変更することにより、両者を合致させることができる。或いは、演算ゲインＡ１の調整前の変化量ΔＳｐ１，ΔＳｐ２等に基づいて、適切な調整後の演算ゲインＡ１の値が算出されてもよい。この場合、例えば上式（２），（３）のＧ１×Ｂｃ，Ｇ２×Ｂｃに対応するセンサ信号Ｓ１，Ｓ２の変化量が参照されてもよい。 In step ST2, matching between the change amounts ΔSp1 and ΔSp2 can be appropriately performed within the range of the tolerance. The tolerance is, for example, ± 0.1%. For example, both can be matched by gradually changing the operation gain A1 while monitoring the respective change amounts ΔSp1 and ΔSp2. Alternatively, the value of the appropriately adjusted operation gain A1 may be calculated based on the amounts of change ΔSp1 and ΔSp2 before adjustment of the operation gain A1 and the like. In this case, for example, the change amounts of the sensor signals S1 and S2 corresponding to G1 × Bc and G2 × Bc of the above equations (2) and (3) may be referred to.
　上記のステップＳＴ２の調整によると、図１１（ｂ）に示すように、第１検出信号Ｓｐ１のグラフの傾きと第２検出信号Ｓｐ２のグラフの傾きとが等しくなる。このような第１及び第２検出信号Ｓｐ１，Ｓｐ２を差動入力することにより、図１１（ｃ）に示すように、同相磁場Ｂｃによっては変動しない出力信号Ｓｏｕｔを得ることができる。よって、電流センサ１における外部磁場耐性を確保することができる。 According to the adjustment in step ST2, as shown in FIG. 11B, the inclination of the graph of the first detection signal Sp1 and the inclination of the graph of the second detection signal Sp2 become equal. By differentially inputting such first and second detection signals Sp1 and Sp2, as shown in FIG. 11C, it is possible to obtain an output signal Sout which does not fluctuate due to the in-phase magnetic field Bc. Therefore, the external magnetic field resistance in the current sensor 1 can be secured.
　図１１（ｃ）の例において、出力信号Ｓｏｕｔは、図１１（ｂ）の第１及び第２検出信号Ｓｐ１，Ｓｐ２間の信号差ΔＯＳに起因するオフセット成分ΔＯｆｓを含んでいる。出力信号Ｓｏｕｔのオフセット成分ΔＯｆｓは、電流の検出時に検出誤差になると想定される。そこで、図９に示す調整方法では、ステップＳＴ２の次に、第１演算部３１による第１検出信号Ｓｐ１のオフセット及び第２演算部３２による第２検出信号Ｓｐ２のオフセットの少なくとも一方を調整する（ＳＴ３）。 In the example of FIG. 11 (c), the output signal Sout includes an offset component ΔOfs resulting from the signal difference ΔOS between the first and second detection signals Sp1 and Sp2 of FIG. 11 (b). The offset component ΔOfs of the output signal Sout is assumed to be a detection error when the current is detected. Therefore, in the adjustment method shown in FIG. 9, after step ST2, at least one of the offset of the first detection signal Sp1 by the first operation unit 31 and the offset of the second detection signal Sp2 by the second operation unit 32 is adjusted ( ST3).
　ステップＳＴ３では、例えば同相磁場Ｂｃが印加されていない状態における第１及び第２検出信号Ｓｐ１，Ｓｐ２間の信号差ΔＯＳが測定される。信号差ΔＯＳは、同相磁場Ｂｃが印加された状態で測定されてもよい。ステップＳＴ３では、第１及び第２検出信号Ｓｐ１，Ｓｐ２間の信号差ΔＯＳが適宜、許容誤差の範囲内で「０」となるように、例えば第２演算部３２のオフセットが調整される（図１１（ｂ）参照）。これにより、出力信号Ｓｏｕｔにおけるオフセット成分ΔＯｆｓが抑制され（図１１（ｃ）参照）、電流センサ１の検出誤差を低減することができる。 In step ST3, for example, the signal difference ΔOS between the first and second detection signals Sp1 and Sp2 in the state where the in-phase magnetic field Bc is not applied is measured. The signal difference ΔOS may be measured in the state where the in-phase magnetic field Bc is applied. In step ST3, for example, the offset of the second operation unit 32 is adjusted so that the signal difference ΔOS between the first and second detection signals Sp1 and Sp2 is appropriately set to “0” within the allowable error range (see FIG. 11 (b)). Thus, the offset component ΔOfs in the output signal Sout is suppressed (see FIG. 11C), and the detection error of the current sensor 1 can be reduced.
　次に、以上のような調整が為された電流センサ１に対して、通電補正を行う（ＳＴ４）。通電補正は、電流センサ１が取り付けられたバスバー２に電流Ｉを流して、電流センサ１の第３演算部３３等を調整するキャリブレーション工程である。図１２を用いて、電流センサ１の通電補正（ＳＴ４）について説明する。 Next, energization correction is performed on the current sensor 1 that has been adjusted as described above (ST4). The energization correction is a calibration process of adjusting the third calculation unit 33 of the current sensor 1 by supplying the current I to the bus bar 2 to which the current sensor 1 is attached. The energization correction (ST4) of the current sensor 1 will be described with reference to FIG.
　図１２（ａ）は、ステップＳＴ４における各センサ信号Ｓ１，Ｓ２と電流Ｉとの関係を示すグラフである。図１２（ｂ）は、図１２（ａ）の各センサ信号Ｓ１，Ｓ２に対して調整済みの各検出信号Ｓｐ１，Ｓｐ２を例示するグラフである。図１２（ｃ）は、図１２（ｂ）の各検出信号Ｓｐ１，Ｓｐ２に基づく出力信号Ｓｏｕｔを例示するグラフである。 FIG. 12A is a graph showing the relationship between the sensor signals S1 and S2 and the current I in step ST4. FIG. 12B is a graph illustrating the detection signals Sp1 and Sp2 which have been adjusted with respect to the sensor signals S1 and S2 of FIG. 12A. FIG.12 (c) is a graph which illustrates the output signal Sout based on each detection signal Sp1 of FIG.12 (b).
　図１２（ａ）は、電流Ｉに基づく信号磁場を感知する２つの磁気センサ１１，１２がばらついている場合における２つのセンサ信号Ｓ１，Ｓ２を例示している。図１２（ａ）の各センサ信号Ｓ１，Ｓ２のグラフでは、互いに逆向きの傾きの大きさが異なっている。また、電流Ｉ＝０の場合の第１及び第２センサ信号Ｓ１，Ｓ２の値がずれている。 FIG. 12A illustrates two sensor signals S1 and S2 in the case where two magnetic sensors 11 and 12 that sense a signal magnetic field based on the current I are dispersed. In the graphs of the sensor signals S1 and S2 in FIG. 12A, the magnitudes of the inclinations in opposite directions are different. Further, the values of the first and second sensor signals S1 and S2 in the case of the current I = 0 are shifted.
　これに対して、図１２（ｂ）に示すように第１及び第２検出信号Ｓｐ１，Ｓｐ２では、ステップＳＴ２の調整により、グラフの傾きの大きさが合致している。また、ステップＳＴ３の調整により、電流Ｉ＝０の場合における第１及び第２検出信号Ｓｐ１，Ｓｐ２の値が合致している。このように調整された各検出信号Ｓｐ１，Ｓｐ２に基づいて、第３演算部３３は、図１２（ｃ）に示すように、電流Ｉに対して線形応答する出力信号Ｓｏｕｔを生成することができる。 On the other hand, as shown in FIG. 12B, in the first and second detection signals Sp1 and Sp2, the magnitudes of the inclinations of the graphs coincide with each other by the adjustment of step ST2. Further, by the adjustment of step ST3, the values of the first and second detection signals Sp1 and Sp2 in the case of the current I = 0 match. Based on the detection signals Sp1 and Sp2 adjusted in this manner, the third operation unit 33 can generate an output signal Sout that linearly responds to the current I, as shown in FIG. 12 (c). .
　ステップＳＴ４の通電補正においては、例えばバスバー２に所望の大きさの電流Ｉを流した場合に応答する出力信号Ｓｏｕｔの値を確認して、第３演算部３３のゲイン及びオフセット等を調整することができる。また、バスバー２の通電による発熱を利用して、電流センサ１における温度補償の確認及び調整を行うこともできる。例えば、第３演算部３３における温度係数の関数形を、各種パラメータを用いて予め設定しておき、通電時における出力信号Ｓｏｕｔの温度ドリフト等をモニタしながら、各種パラメータを調整することができる。 In the energization correction of step ST4, for example, the value of the output signal Sout that responds when the current I of a desired magnitude is supplied to the bus bar 2 is checked to adjust the gain, offset, and the like of the third arithmetic unit 33. Can. In addition, it is also possible to check and adjust the temperature compensation in the current sensor 1 by using the heat generated by the energization of the bus bar 2. For example, the function form of the temperature coefficient in the third calculation unit 33 can be set in advance using various parameters, and various parameters can be adjusted while monitoring temperature drift or the like of the output signal Sout during energization.
　ステップＳＴ４の通電補正を完了することにより、図９に示す調整方法は終了する。 The adjustment method shown in FIG. 9 is completed by completing the energization correction in step ST4.
　以上の調整方法によると、同相磁場Ｂｃに応じた各検出信号Ｓｐ１，Ｓｐ２の変化量ΔＳｐ１，ΔＳｐ２を合致させる調整により（ＳＴ２）、調整後の電流センサ１では、同相磁場Ｂｃに基づく式（２），（３）から式（１）が成立する。すなわち、ステップＳＴ２では、第１磁気検出部１０ＡによるゲインＧ１×Ａ１と、第２磁気検出部１０ＢによるゲインＧ２×Ａ２とを合致させるように、調整部４が設定される。このように、電流センサ１の製造工程において、外部磁場耐性を確保する設定を行うことができる。 According to the above adjustment method, the current sensor 1 after adjustment is adjusted by matching the variation amounts ΔSp1 and ΔSp2 of the detection signals Sp1 and Sp2 according to the in-phase magnetic field Bc (ST2). Formula (1) is established from (3) and (3). That is, in step ST2, the adjustment unit 4 is set so that the gain G1 × A1 of the first magnetic detection unit 10A and the gain G2 × A2 of the second magnetic detection unit 10B coincide with each other. As described above, in the manufacturing process of the current sensor 1, the setting for securing the external magnetic field resistance can be performed.
　また、以上の説明では、電流センサ１がバスバー２に取り付けられた状態でステップＳＴ１～ＳＴ３が行われる例を説明したが、ステップＳＴ１～ＳＴ３において電流センサ１はバスバー２に取り付けられていなくてもよい。ステップＳＴ１において同相磁場Ｂｃが印加される状態の別例を図１３に示す。 In the above description, an example in which steps ST1 to ST3 are performed in a state where current sensor 1 is attached to bus bar 2 has been described, but even if current sensor 1 is not attached to bus bar 2 in steps ST1 to ST3. Good. Another example of a state in which the in-phase magnetic field Bc is applied in step ST1 is shown in FIG.
　図１３においては、特にバスバー２に取り付けられていない電流センサ１に対して、図１０の例と同様に同相磁場Ｂｃが印加されている。このような状態においても、ステップＳＴ２，ＳＴ３の調整を行うことができる。これにより、例えば、電流センサ１を取り付けるバスバー２の形状が複雑な場合であっても、ステップＳＴ１～ＳＴ３を容易に実施可能である。 In FIG. 13, the in-phase magnetic field Bc is applied to the current sensor 1 particularly not attached to the bus bar 2 as in the example of FIG. 10. Even in such a state, the adjustment of steps ST2 and ST3 can be performed. Thus, for example, even if the shape of the bus bar 2 to which the current sensor 1 is attached is complicated, the steps ST1 to ST3 can be easily implemented.
　また、上述したステップＳＴ４の通電補正は、ステップＳＴ１～ＳＴ３の後に、電流センサ１をバスバー２に取り付けた状態において実施される。通電補正（ＳＴ４）は、例えば三相交流の測定用など、複数の電流センサ１が各々バスバー２に組み付けられた電流センサユニットが製造される場合に、電流センサユニットを組み上げた状態において、実施することもできる。 Further, the energization correction of step ST4 described above is performed in a state where the current sensor 1 is attached to the bus bar 2 after steps ST1 to ST3. The conduction correction (ST4) is performed in a state where the current sensor unit is assembled, for example, for measurement of three-phase alternating current, when a current sensor unit in which a plurality of current sensors 1 are assembled to the bus bar 2 is manufactured. It can also be done.
　また、以上の説明では、ステップＳＴ２において第１演算部３１の演算ゲインＡ１を調整する例を説明したが、ステップＳＴ２は特にこれに限らない。ステップＳＴ２では、第２演算部３２の演算ゲインＡ２が調整されてもよいし、双方の演算ゲインＡ１，Ａ２が調整されてもよい。 In the above description, although the example in which the operation gain A1 of the first operation unit 31 is adjusted in step ST2 has been described, step ST2 is not particularly limited thereto. In step ST2, the operation gain A2 of the second operation unit 32 may be adjusted, or both operation gains A1 and A2 may be adjusted.
　また、以上の説明では、ステップＳＴ３のオフセット調整が、ステップＳＴ２の後に実施されたが、ステップＳＴ３は特にこれに限らない。例えば、ステップＳＴ３はステップＳＴ１，ＳＴ２の前に実施されてもよい。また、特に第１及び第２演算部３１，３２のオフセット調整が必要ない場合等には、適宜、ステップＳＴ３の調整が省略されてもよい。 In the above description, the offset adjustment in step ST3 is performed after step ST2, but step ST3 is not particularly limited to this. For example, step ST3 may be performed before steps ST1 and ST2. Further, the adjustment of step ST3 may be omitted as appropriate, in particular, when the offset adjustment of the first and second calculation units 31, 32 is not necessary.
３．まとめ
　以上のように、本実施形態に係る電流センサ１の製造方法は、検出対象の電流Ｉによって生じる信号磁場Ｂ１，Ｂ２に基づき電流Ｉを検出する電流センサ１の製造方法である。本方法は、電流センサ１を準備する工程と、同相磁場Ｂｃを電流センサ１に印加する工程（ＳＴ１）と、電流センサ１における信号のゲインを調整する工程（ＳＴ２）とを含む。電流センサ１は、磁場を感知する第１磁気センサ１１と、電流Ｉに応じて第１磁気センサ１１が感知する信号磁場Ｂ１とは逆相の信号磁場Ｂ２を感知する第２磁気センサ１２と、出力部の一例である演算装置３とを備える。演算装置３は、第１磁気センサ１１の感知結果と第２磁気センサ１２の感知結果との差動増幅を演算して、電流Ｉの検出結果を示す出力信号Ｓｏｕｔを生成する。同相磁場Ｂｃは、第１磁気センサ１１と第２磁気センサ１２とに同相で入力される。ゲインを調整する工程は、同相磁場Ｂｃに応じて、第１及び第２磁気センサ１１，１２の感知結果として演算装置３に差動増幅される２つの信号量の一例として、第１及び第２検出信号Ｓｐ１，Ｓｐ２の変化量ΔＳｐ１，ΔＳｐ２が合致するように、電流センサ１における信号のゲインを調整する。 3. As described above, the method of manufacturing the current sensor 1 according to this embodiment is a method of manufacturing the current sensor 1 that detects the current I based on the signal magnetic fields B1 and B2 generated by the current I to be detected. The method includes the steps of preparing the current sensor 1, applying the in-phase magnetic field Bc to the current sensor 1 (ST1), and adjusting the gain of the signal in the current sensor 1 (ST2). The current sensor 1 includes a first magnetic sensor 11 that senses a magnetic field, and a second magnetic sensor 12 that senses a signal magnetic field B2 in reverse phase to the signal magnetic field B1 sensed by the first magnetic sensor 11 according to the current I. And an arithmetic unit 3 which is an example of an output unit. The arithmetic unit 3 calculates differential amplification between the sensing result of the first magnetic sensor 11 and the sensing result of the second magnetic sensor 12 to generate an output signal Sout indicating the detection result of the current I. The in-phase magnetic field Bc is input to the first magnetic sensor 11 and the second magnetic sensor 12 in the same phase. The step of adjusting the gain includes, as an example of two signal amounts differentially amplified in the arithmetic device 3 as sensing results of the first and second magnetic sensors 11 and 12 according to the in-phase magnetic field Bc, the first and second The gain of the signal in the current sensor 1 is adjusted so that the change amounts ΔSp1 and ΔSp2 of the detection signals Sp1 and Sp2 match.
　以上の方法によると、同相磁場Ｂｃに応じた変化量ΔＳｐ１，ΔＳｐ２が合致するように調整されることにより、外部磁場耐性を確保した電流センサ１を製造でき、電流センサ１における外部磁場の影響を低減することができる。 According to the above method, the current sensor 1 having resistance to the external magnetic field can be manufactured by adjusting the amounts of change ΔSp1 and ΔSp2 according to the in-phase magnetic field Bc to coincide with each other. It can be reduced.
　本実施形態において、同相磁場Ｂｃは、均一な空間分布を有する。均一な同相磁場Ｂｃを用いることにより、電流センサ１のゲインの調整を適切に行うことができる。 In the present embodiment, the in-phase magnetic field Bc has a uniform spatial distribution. By using the uniform in-phase magnetic field Bc, the gain of the current sensor 1 can be appropriately adjusted.
　また、本実施形態において、第１磁気センサ１１は、センサゲインＧ１（第１のセンサゲイン）において第１センサ信号Ｓ１を生成する。第２磁気センサ１２は、センサゲインＧ２（第２のセンサゲイン）において第２センサ信号Ｓ２を生成する。演算装置３は、第１演算部３１と、第２演算部３２と、第３演算部３３とを備える。第１演算部３１は、第１センサ信号Ｓ１を入力して、入力した信号に演算ゲインＡ１（第１の演算ゲイン）を乗算する。第２演算部３２は、第２センサ信号Ｓ２を入力して、入力した信号に演算ゲインＡ２（第２の演算ゲイン）を乗算する。第３演算部３３は、第１演算部３１の演算結果と第２演算部３２の演算結果とに基づき出力信号Ｓｏｕｔを算出する。ゲインを調整する工程（ＳＴ２）は、演算ゲインＡ１，Ａ２の少なくとも一方を調整する。 Further, in the present embodiment, the first magnetic sensor 11 generates the first sensor signal S1 in the sensor gain G1 (first sensor gain). The second magnetic sensor 12 generates a second sensor signal S2 at a sensor gain G2 (second sensor gain). The arithmetic device 3 includes a first arithmetic unit 31, a second arithmetic unit 32, and a third arithmetic unit 33. The first operation unit 31 receives the first sensor signal S1 and multiplies the received signal by the operation gain A1 (first operation gain). The second operation unit 32 receives the second sensor signal S2 and multiplies the input signal by the operation gain A2 (second operation gain). The third operation unit 33 calculates an output signal Sout based on the operation result of the first operation unit 31 and the operation result of the second operation unit 32. The step of adjusting the gain (ST2) adjusts at least one of the operation gains A1 and A2.
　これにより、磁気センサ１１，１２のセンサゲインＧ１，Ｇ２間にばらつきがあっても、外部磁場耐性を確保することができる。また、電流センサ１における２つの磁気センサ１１，１２間の製造ばらつきを抑える必要性をなくして、任意の磁気センサ１１，１２を使用可能にすることもできる。 Thereby, even if there is a variation between the sensor gains G1 and G2 of the magnetic sensors 11 and 12, the external magnetic field resistance can be secured. Further, it is possible to make it possible to use any of the magnetic sensors 11 and 12 without the need to suppress the manufacturing variation between the two magnetic sensors 11 and 12 in the current sensor 1.
　また、本実施形態において、ゲインを調整する工程（ＳＴ２）は、第１磁気検出部１０ＡにおけるセンサゲインＧ１と演算ゲインＡ１の積と、第２磁気検出部１０ＢにおけるセンサゲインＧ２と演算ゲインＡ２の積とが合致するように、少なくとも１つのゲインを調整する（式（１）参照）。これにより、第１検出信号Ｓｐ１と第２検出信号Ｓｐ２とにおける外部磁場の影響を精度良く打ち消して、出力信号Ｓｏｕｔにおける外部磁場の影響を低減することができる。 Further, in the present embodiment, the step (ST2) of adjusting the gain includes the product of the sensor gain G1 and the operation gain A1 in the first magnetic detection unit 10A, and the sensor gain G2 and the operation gain A2 in the second magnetic detection unit 10B. At least one gain is adjusted to match the product (see equation (1)). Thereby, the influence of the external magnetic field in the first detection signal Sp1 and the second detection signal Sp2 can be canceled accurately, and the influence of the external magnetic field in the output signal Sout can be reduced.
　また、本実施形態に係る電流センサ１は、第１磁気センサ１１と、第１演算部３１と、第２磁気センサ１２と、第２演算部３２と、第３演算部３３と、調整部４とを備える。第１磁気センサ１１は、センサゲインＧ１において磁場を感知する。第１演算部３１は、第１磁気センサ１１の感知結果に演算ゲインＡ１を乗算する。第２磁気センサ１２は、電流Ｉに応じて第１磁気センサ１１が感知する信号磁場Ｂ１とは逆相の信号磁場Ｂ２を、センサゲインＧ２において感知する。第２演算部３２は、第２磁気センサ１２の感知結果に演算ゲインＡ２を乗算する。第３演算部３３は、第１及び第２演算部３１，３２の演算結果に基づき電流Ｉの検出結果を示す出力信号Ｓｏｕｔを算出する。調整部４は、演算ゲインＡ１，Ａ２のうちの少なくとも一方を調整する。調整部４は、センサゲインＧ１と演算ゲインＡ１の積と、センサゲインＧ２と演算ゲインＡ２の積とを合致させる。これにより、電流センサ１において、外部磁場の影響を低減することができる。 Further, the current sensor 1 according to the present embodiment includes the first magnetic sensor 11, the first arithmetic unit 31, the second magnetic sensor 12, the second arithmetic unit 32, the third arithmetic unit 33, and the adjustment unit 4. And The first magnetic sensor 11 senses a magnetic field at the sensor gain G1. The first calculation unit 31 multiplies the detection result of the first magnetic sensor 11 by the calculation gain A1. The second magnetic sensor 12 senses at the sensor gain G2 a signal magnetic field B2 opposite in phase to the signal magnetic field B1 sensed by the first magnetic sensor 11 according to the current I. The second calculation unit 32 multiplies the detection result of the second magnetic sensor 12 by the calculation gain A2. The third operation unit 33 calculates an output signal Sout indicating the detection result of the current I based on the operation results of the first and second operation units 31 and 32. The adjustment unit 4 adjusts at least one of the operation gains A1 and A2. The adjustment unit 4 matches the product of the sensor gain G1 and the operation gain A1 with the product of the sensor gain G2 and the operation gain A2. Thereby, in the current sensor 1, the influence of the external magnetic field can be reduced.
　また、本実施形態において、調整部４は、第１磁気センサ１１と第２磁気センサ１２とに同相で磁場Ｂｃが入力されたときに（ＳＴ１）、同相磁場Ｂｃに応じて、第１演算部３１の演算結果を示す信号量としての変化量ΔＳｐ１と第２演算部３２の演算結果を示す信号量としての変化量ΔＳｐ２とが合致するように、少なくとも１つのゲインを調整する（ＳＴ２）。このような同相磁場Ｂｃを入力することによって、調整部４の調整機能が確認できる。 Further, in the present embodiment, when the magnetic field Bc is input in the same phase to the first magnetic sensor 11 and the second magnetic sensor 12 (ST1), the adjustment unit 4 calculates the first operation unit according to the in-phase magnetic field Bc. At least one gain is adjusted so that the change amount ΔSp1 as a signal amount indicating the calculation result of 31 and the change amount ΔSp2 as the signal amount indicating the calculation result of the second calculation unit 32 match (ST2). By inputting such an in-phase magnetic field Bc, the adjustment function of the adjustment unit 4 can be confirmed.
　なお、調整部４は、特に同相磁場Ｂｃを用いずに設定されてもよい。調整部４の設定は、式（１）を適宜許容誤差の範囲内で成立させる、「Ａ１×Ｇ１」と「Ａ２×Ｇ２」とを合致させるように行われてもよい。 The adjustment unit 4 may be set without particularly using the in-phase magnetic field Bc. The setting of the adjustment unit 4 may be performed such that “A1 × G1” and “A2 × G2” match the equation (1) appropriately within the range of the allowable error.
（実施形態２）
　実施形態１では、演算ゲインＡ１，Ａ２が調整される電流センサ１について説明した。演算ゲインＡ１，Ａ２に限らず、センサゲインＧ１，Ｇ２の調整によっても電流センサの外部磁場耐性を確保することができる。実施形態２では、センサゲインＧ１，Ｇ２が調整される電流センサについて、図１４，１５を用いて説明する。 Second Embodiment
In the first embodiment, the current sensor 1 in which the calculation gains A1 and A2 are adjusted has been described. The external magnetic field resistance of the current sensor can be secured not only by the calculation gains A1 and A2 but also by adjusting the sensor gains G1 and G2. In the second embodiment, a current sensor in which the sensor gains G1 and G2 are adjusted will be described with reference to FIGS.
　図１４は、実施形態２に係る電流センサ１Ａの構成を示すブロック図である。本実施形態に係る電流センサ１Ａは、実施形態１の電流センサ１と同様の構成において（図２参照）、図１４に示すように、調整部４Ａが第１及び第２磁気センサ１１，１２のセンサゲインＧ１，Ｇ２を調整するように構成される。 FIG. 14 is a block diagram showing the configuration of the current sensor 1A according to the second embodiment. The current sensor 1A according to the present embodiment has the same configuration as the current sensor 1 according to the first embodiment (see FIG. 2), and as shown in FIG. It is configured to adjust the sensor gains G1 and G2.
　本実施形態における調整部４Ａは、実施形態１の調整部４と同様に、上述した式（１）を成立させるように、第１磁気センサ１１のセンサゲインＧ１と第２磁気センサ１２のセンサゲインＧ２との少なくとも一方を調整する。本実施形態の電流センサ１Ａは、例えば実施形態１と同様の製造方法において、図９のステップＳＴ２において、調整部４を用いてセンサゲインＧ１，Ｇ２の少なくとも一方を調整することにより製造できる。 The adjusting unit 4A in the present embodiment, like the adjusting unit 4 in the first embodiment, has the sensor gain G1 of the first magnetic sensor 11 and the sensor gain of the second magnetic sensor 12 so as to satisfy the above equation (1). Adjust at least one with G2. The current sensor 1A of this embodiment can be manufactured, for example, by adjusting at least one of the sensor gains G1 and G2 using the adjusting unit 4 in step ST2 of FIG. 9 in the same manufacturing method as that of the first embodiment.
　本実施形態における調整部４Ａとしては、センサゲインＧ１，Ｇ２を調整可能な種々の構成を採用することができる。例えば第１及び第２磁気センサ１１，１２を駆動する電圧又は電流を制御することにより、各々のセンサゲインＧ１，Ｇ２を調整する。図１５（ａ），（ｂ），（ｃ）に、本実施形態における調整部４Ａの第１、第２及び第３の構成例を示す。 As adjustment part 4A in this embodiment, various composition which can adjust sensor gain G1 and G2 is employable. For example, each sensor gain G1, G2 is adjusted by controlling the voltage or current which drives the 1st and 2nd magnetic sensor 11,12. 15 (a), (b) and (c) show first, second and third configuration examples of the adjustment unit 4A in the present embodiment.
　第１の構成例において、調整部４Ａは、図１５（ａ）に示すように、電源電圧Ｖｄｄの電源と第１磁気センサ１１の間に接続される抵抗４２Ａと、電源と第２磁気センサ１２との間に接続される抵抗４２Ｂとを備える。各抵抗４２Ａ，４２Ｂは、例えば各々の抵抗値Ｒａ，Ｒｂを半固定又は可変に構成される。 In the first configuration example, as illustrated in FIG. 15A, the adjustment unit 4A includes a resistor 42A connected between the power supply of the power supply voltage Vdd and the first magnetic sensor 11, a power supply, and the second magnetic sensor 12 And a resistor 42B connected therebetween. Each of the resistors 42A and 42B, for example, is configured such that each of the resistance values Ra and Rb is fixed or variable.
　図１５（ａ）の構成例において、調整部４Ａは、各抵抗４２Ａ，４２Ｂを介して、第１磁気センサ１１に供給する駆動電圧Ｖ１１と、第２磁気センサ１２に供給する駆動電圧Ｖ１２とを制御する。各々の抵抗値Ｒａ，Ｒｂは、例えば図９のステップＳＴ２において、実施形態１と同様にレーザトリム、ツェナーザッピング、抵抗リンク、ＥＥＰＲＯＭトリム、デジタルトリム等の各種手法によって設定される。 In the configuration example of FIG. 15 (a), the adjustment unit 4A drives the drive voltage V11 supplied to the first magnetic sensor 11 and the drive voltage V12 supplied to the second magnetic sensor 12 via the respective resistors 42A and 42B. Control. The respective resistance values Ra and Rb are set, for example, in step ST2 of FIG. 9 by various methods such as laser trim, zener zapping, resistive link, EEPROM trim, digital trim and the like as in the first embodiment.
　第２の構成例において、調整部４Ａは、図１５（ｂ）に示すように、第１磁気センサ１１の駆動電圧Ｖ１１を生成する電圧制御回路４３Ａと、第２磁気センサ１２の駆動電圧Ｖ１２を生成する電圧制御回路４３Ｂとを備える。本例において、各電圧制御回路４３Ａ，４３Ｂは、それぞれ基準電圧Ｖｒｅｆ１，Ｖｒｅｆ２を入力するオペアンプと、ＮＭＯＳトランジスタとを備える。 In the second configuration example, as shown in FIG. 15B, the adjustment unit 4A generates a drive voltage V11 of the first magnetic sensor 11 and a drive voltage V12 of the second magnetic sensor 12 as shown in FIG. And a voltage control circuit 43B to generate. In this example, each of the voltage control circuits 43A and 43B includes an operational amplifier for receiving the reference voltages Vref1 and Vref2 and an NMOS transistor.
　図１５（ｂ）の構成例の調整部４Ａにおいて、各電圧制御回路４３Ａ，４３Ｂは、それぞれ基準電圧Ｖｒｅｆ１，Ｖｒｅｆ２に合致させるように、各磁気センサ１１，１２の駆動電圧Ｖ１１，Ｖ１２を制御する。上記の第１の構成例と同様に各種手法等によって、各基準電圧Ｖｒｅｆ１，Ｖｒｅｆ２を設定することにより、各駆動電圧Ｖ１１，Ｖ１２を調整することができる。 In the adjustment unit 4A of the configuration example of FIG. 15B, the voltage control circuits 43A and 43B control the drive voltages V11 and V12 of the magnetic sensors 11 and 12 to match the reference voltages Vref1 and Vref2, respectively. . The drive voltages V11 and V12 can be adjusted by setting the reference voltages Vref1 and Vref2 by various methods or the like as in the first configuration example described above.
　第３の構成例において、調整部４Ａは、図１５（ｃ）に示すように、第１磁気センサ１１の駆動電流Ｉ１１を生成する電流制御回路４４Ａと、第２磁気センサ１２の駆動電流Ｉ１２を生成する電流制御回路４４Ｂとを備える。本例において、各電流制御回路４４Ａ，４４Ｂは、それぞれ抵抗値Ｒａ，Ｒｂを有する抵抗と、基準電圧Ｖｒｅｆ１，Ｖｒｅｆ２を入力するオペアンプと、ＰＭＯＳトランジスタとを備える。 In the third configuration example, as shown in FIG. 15C, the adjustment unit 4A generates a current control circuit 44A that generates a drive current I11 of the first magnetic sensor 11 and a drive current I12 of the second magnetic sensor 12 And a current control circuit 44B to generate. In this example, each of the current control circuits 44A and 44B includes resistors having resistance values Ra and Rb, an operational amplifier for receiving the reference voltages Vref1 and Vref2, and a PMOS transistor.
　図１５（ｃ）の構成例の調整部４Ａにおいて、各電流制御回路４４Ａ，４４Ｂは、それぞれ次式（２１），（２２）のように各磁気センサ１１，１２の駆動電流Ｉ１１，Ｉ１２を制御する。 In the adjustment unit 4A of the configuration example of FIG. 15C, the current control circuits 44A and 44B control the drive currents I11 and I12 of the magnetic sensors 11 and 12 as in the following equations (21) and (22), respectively. Do.
Ｉ１１＝（Ｖｄｄ－Ｖｒｅｆ１）／Ｒ１１　　　…（２１）
Ｉ１２＝（Ｖｄｄ－Ｖｒｅｆ２）／Ｒ１２　　　…（２２）
　本構成例においては、上式（２１），（２２）に基づき、各基準電圧Ｖｒｅｆ，Ｖｒｅｆ２、或いは抵抗値Ｒａ，Ｒｂを設定することにより、各駆動電流Ｉ１１，Ｉ１２を調整することができる。本構成例においても、第１及び第２の構成例と同様に、各種手法等を適用して上記の調整を行える。 I11 = (Vdd-Vref1) / R11 (21)
I12 = (Vdd-Vref2) / R12 (22)
In the present configuration example, the drive currents I11 and I12 can be adjusted by setting the reference voltages Vref and Vref2 or the resistance values Ra and Rb based on the equations (21) and (22). Also in this configuration example, as in the first and second configuration examples, the above-described adjustment can be performed by applying various methods and the like.
　以上の説明では、本実施形態の調整部４Ａが２つの磁気センサ１１，１２の双方のセンサゲインＧ１，Ｇ２を調整可能に構成される例を説明した。本実施形態の調整部４Ａは、特にこれに限らず、２つの磁気センサ１１，１２のセンサゲインＧ１，Ｇ２のうちのいずれか一方を調整可能に構成されてもよい。 In the above description, an example in which the adjustment unit 4A of the present embodiment is configured to be able to adjust the sensor gains G1 and G2 of both of the two magnetic sensors 11 and 12 has been described. The adjustment unit 4A of the present embodiment is not particularly limited thereto, and one of the sensor gains G1 and G2 of the two magnetic sensors 11 and 12 may be adjustable.
　以上のように、本実施形態に係る電流センサ１Ａにおいて、調整部４Ａは、センサゲインＧ１，Ｇ２の少なくとも一方を調整する。また、本実施形態に係る電流センサ１Ａの製造方法において、ゲインを調整する工程（図９のＳＴ２）は、センサゲインＧ１，Ｇ２の少なくとも一方を調整する。 As described above, in the current sensor 1A according to the present embodiment, the adjustment unit 4A adjusts at least one of the sensor gains G1 and G2. Further, in the method of manufacturing the current sensor 1A according to the present embodiment, in the step of adjusting the gain (ST2 in FIG. 9), at least one of the sensor gains G1 and G2 is adjusted.
　これにより、例えば第１演算部３１の演算ゲインＡ１と、第２演算部３２の演算ゲインＡ２との間にばらつきがある場合であっても外部磁場耐性を確保して、電流センサ１Ａにおける外部磁場の影響を低減することができる。 Thereby, even if there is a variation between the operation gain A1 of the first operation unit 31 and the operation gain A2 of the second operation unit 32, for example, external magnetic field resistance in the current sensor 1A can be ensured. Can reduce the effects of
　上記の実施形態１，２では、演算ゲインＡ１，Ａ２とセンサゲインＧ１，Ｇ２とのうちの一方を調整する電流センサ１，１Ａ及びその製造方法について説明した。これに限らず、演算ゲインＡ１，Ａ２とセンサゲインＧ１，Ｇ２との双方が調整可能な電流センサ及びその製造方法が提供されてもよい。即ち、本実施形態に係る電流センサは、２つの演算ゲインＡ１，Ａ２と２つのセンサゲインＧ１，Ｇ２のうちの少なくとも１つのゲインを調整する調整部を備えてもよい。また、本実施形態に係る電流センサの製造方法において、ゲインを調整する工程は、２つの演算ゲインＡ１，Ａ２と２つのセンサゲインＧ１，Ｇ２のうちの少なくとも１つのゲインを調整してもよい。これによっても、電流センサにおける外部磁場の影響を低減することができる。 In Embodiments 1 and 2 described above, the current sensors 1 and 1A for adjusting one of the operation gains A1 and A2 and the sensor gains G1 and G2 and the method for manufacturing the same have been described. The present invention is not limited to this, and a current sensor capable of adjusting both of the operation gains A1, A2 and the sensor gains G1, G2 and a method of manufacturing the same may be provided. That is, the current sensor according to the present embodiment may include an adjustment unit that adjusts at least one of two calculation gains A1 and A2 and two sensor gains G1 and G2. Further, in the method of manufacturing the current sensor according to the present embodiment, in the step of adjusting the gain, at least one of the two operation gains A1 and A2 and the two sensor gains G1 and G2 may be adjusted. This can also reduce the influence of the external magnetic field in the current sensor.
（実施形態３）
　実施形態３では、周囲の温度に応じて調整部が動作する電流センサについて説明する。実施形態３に係る電流センサについて、図１６を参照して説明する。 (Embodiment 3)
In the third embodiment, a current sensor in which the adjustment unit operates according to the ambient temperature will be described. The current sensor according to the third embodiment will be described with reference to FIG.
　図１６は、実施形態３に係る電流センサ１Ｂの構成を示すブロック図である。本実施形態に係る電流センサ１Ｂは、実施形態１の電流センサ１と同様の構成において（図２参照）、図１６に示すように、調整部４Ｂが、温度検出部３４によって検出される温度に基づき動作する。 FIG. 16 is a block diagram showing the configuration of the current sensor 1B according to the third embodiment. The current sensor 1B according to the present embodiment has the same configuration as that of the current sensor 1 according to the first embodiment (see FIG. 2), and as shown in FIG. Operate based on.
　本実施形態における調整部４Ｂは、例えば実施形態１と同様の構成に加えて、温度補償回路等を備える。本実施形態の調整部４Ｂは、例えば温度検出部３４によって検出される温度に応じて、式（１）についての許容誤差の範囲から脱しないように、演算ゲインＡ１，Ａ２の少なくとも一方を調整する。これにより、種々の温度環境下において、電流センサ１Ｂの外部磁場耐性を向上することができる。 The adjustment unit 4B in the present embodiment includes, for example, a temperature compensation circuit and the like in addition to the same configuration as that of the first embodiment. The adjustment unit 4B according to the present embodiment adjusts at least one of the operation gains A1 and A2 so as not to deviate from the range of the allowable error for the equation (1), for example, according to the temperature detected by the temperature detection unit 34. . Thus, the external magnetic field resistance of the current sensor 1B can be improved under various temperature environments.
　以上の説明では、温度に応じて調整部４Ｂが演算ゲインＡ１，Ａ２を調整する例を説明した。これに限らず、例えば実施形態２と同様に、調整部４Ｂが、温度に応じてセンサゲインＧ１，Ｇ２を調整してもよい。また、温度検出部３４は、調整部４Ｂの温度補償回路に組み込まれていてもよい。 In the above description, an example in which the adjustment unit 4B adjusts the operation gains A1 and A2 in accordance with the temperature has been described. Not limited to this, for example, as in the second embodiment, the adjustment unit 4B may adjust the sensor gains G1 and G2 according to the temperature. In addition, the temperature detection unit 34 may be incorporated in the temperature compensation circuit of the adjustment unit 4B.
　以上のように、本実施形態に係る電流センサ１Ｂは、周囲の温度を検出する温度検出部３４をさらに備える。調整部４Ａは、温度検出部３４によって検出される温度に応じて、演算ゲインＡ１，Ａ２及びセンサゲインＧ１，Ｇ２のうちの少なくとも１つのゲインを調整する。これにより、種々の温度環境下において、電流センサ１Ｂにおける外部磁場の影響を低減できる。 As described above, the current sensor 1B according to the present embodiment further includes the temperature detection unit 34 that detects the ambient temperature. The adjustment unit 4A adjusts at least one of the operation gains A1 and A2 and the sensor gains G1 and G2 in accordance with the temperature detected by the temperature detection unit 34. Thereby, under various temperature environments, the influence of the external magnetic field in the current sensor 1B can be reduced.
（実施形態４）
　実施形態４では、実施形態２とは演算装置と磁気センサ間の接続関係が異なる電流センサについて説明する。実施形態４に係る電流センサについて、図１７，１８を参照して説明する。 (Embodiment 4)
In the fourth embodiment, a current sensor which is different from the second embodiment in the connection relationship between the arithmetic device and the magnetic sensor will be described. The current sensor according to the fourth embodiment will be described with reference to FIGS.
　図１７は、実施形態４に係る電流センサ１Ｃの構成を示すブロック図である。本実施形態に係る電流センサ１Ｃは、実施形態２の電流センサ１Ａと同様の構成において（図１４参照）、第１及び第２磁気センサ１１Ａ，１２Ａの双方が、第１及び第２演算部３１Ａ，３２Ａの双方に接続される。本実施形態において、第１及び第２磁気センサ１１Ａ，１２Ａは差動出力し、第１及び第２演算部３１Ａ，３２Ａは差動入力する。本実施形態の各磁気センサ１１Ａ，１２Ａは、例えば図３の構成例の磁気センサ１１と同様に構成される。 FIG. 17 is a block diagram showing the configuration of a current sensor 1C according to the fourth embodiment. The current sensor 1C according to the present embodiment has the same configuration as the current sensor 1A of the second embodiment (see FIG. 14), and both of the first and second magnetic sensors 11A and 12A are the first and second calculation units 31A. , 32A are connected. In the present embodiment, the first and second magnetic sensors 11A and 12A output differentially, and the first and second arithmetic units 31A and 32A input differentially. Each magnetic sensor 11A, 12A of this embodiment is comprised similarly to the magnetic sensor 11 of the structural example of FIG. 3, for example.
　第１磁気センサ１１Ａは、次式（４１），（４２）のように互いに差動のセンサ信号Ｓ１ｐ，Ｓ１ｍを生成する。 The first magnetic sensor 11A generates sensor signals S1p and S1m which are differential from each other as expressed by the following equations (41) and (42).
Ｓ１ｐ＝Ｖｄｄ／２＋ＤＳ１／２　　　　　　　　　　　　　　…（４１）
Ｓ１ｍ＝Ｖｄｄ／２－ＤＳ１／２　　　　　　　　　　　　　　…（４２）
　上式（４１），（４２）において、ＤＳ１は、第１磁気センサ１１Ａのセンサ信号Ｓ１ｐ，Ｓ１ｍ間の信号差である。信号差ＤＳ１は、例えば図６の例の信号磁場Ｂ１が入力された場合に正となる。 S1p = Vdd / 2 + DS1 / 2 (41)
S1m = Vdd / 2-DS1 / 2 (42)
In the above equations (41) and (42), DS1 is a signal difference between the sensor signals S1p and S1m of the first magnetic sensor 11A. The signal difference DS1 is positive when, for example, the signal magnetic field B1 in the example of FIG. 6 is input.
　また、第１磁気センサ１１Ａと同様に、第２磁気センサ１２Ａは、次式（４３），（４４）のように互いに差動のセンサ信号Ｓ２ｐ，Ｓ２ｍを生成する。 Further, similarly to the first magnetic sensor 11A, the second magnetic sensor 12A generates sensor signals S2p and S2m which are differential from each other as expressed by the following equations (43) and (44).
Ｓ２ｐ＝Ｖｄｄ／２＋ＤＳ２／２　　　　　　　　　　　　　　…（４３）
Ｓ２ｍ＝Ｖｄｄ／２－ＤＳ２／２　　　　　　　　　　　　　　…（４４）
　上式（４３），（４４）において、ＤＳ２は、第２磁気センサ１２Ａのセンサ信号Ｓ２ｐ，Ｓ２ｍ間の信号差である。信号差ＤＳ２は、例えば図６の例の信号磁場Ｂ２が入力された場合に正となる。 S2p = Vdd / 2 + DS2 / 2 (43)
S2m = Vdd / 2-DS2 / 2 (44)
In the above equations (43) and (44), DS2 is a signal difference between the sensor signals S2p and S2m of the second magnetic sensor 12A. The signal difference DS2 is positive when, for example, the signal magnetic field B2 in the example of FIG. 6 is input.
　第１演算部３１Ａは、例えば、第１磁気センサ１１Ａからのセンサ信号Ｓ１ｐと第２磁気センサ１２Ａからのセンサ信号Ｓ２ｍとを入力し、次式（４５）のように第１演算信号Ｓｏ１を算出する。 For example, the first calculation unit 31A receives the sensor signal S1p from the first magnetic sensor 11A and the sensor signal S2m from the second magnetic sensor 12A, and calculates the first calculation signal So1 as in the following equation (45) Do.
Ｓｏ１＝Ａ１×（Ｓ１ｐ－Ｓ２ｍ）　　　　　　　　　　　　　…（４５）
　即ち、第１演算部３１Ａは、演算ゲインＡ１の乗算と、センサ信号Ｓ１ｐ，Ｓ２ｍ間の減算とを演算する。本実施形態において、第１磁気センサ１１Ａからのセンサ信号Ｓ１ｐは第１センサ信号の一例であり、第２磁気センサ１２からのセンサ信号Ｓ２ｍは第４センサ信号の一例である。第１演算部３１Ａは、算出した第１演算信号Ｓｏ１を第３演算部３３に出力する。 So1 = A1 × (S1p−S2m) (45)
That is, the first calculation unit 31A calculates the multiplication of the calculation gain A1 and the subtraction between the sensor signals S1p and S2m. In the present embodiment, the sensor signal S1p from the first magnetic sensor 11A is an example of a first sensor signal, and the sensor signal S2m from the second magnetic sensor 12 is an example of a fourth sensor signal. The first calculation unit 31A outputs the calculated first calculation signal So1 to the third calculation unit 33.
　一方、第２演算部３２Ａは、第１磁気センサ１１Ａからのセンサ信号Ｓ１ｍと第２磁気センサ１２Ａからのセンサ信号Ｓ２ｐとを入力し、次式（４６）のように第２演算信号Ｓｏ２を算出する。 On the other hand, the second operation unit 32A receives the sensor signal S1m from the first magnetic sensor 11A and the sensor signal S2p from the second magnetic sensor 12A, and calculates the second operation signal So2 as in the following equation (46) Do.
Ｓｏ２＝Ａ２×（Ｓ１ｍ－Ｓ２ｐ）　　　　　　　　　　　　　…（４６）
　即ち、第２演算部３２Ａは、演算ゲインＡ２の乗算と、センサ信号Ｓ１ｍ，Ｓ２ｐ間の減算とを演算する。本実施形態において、第１磁気センサ１１Ａからのセンサ信号Ｓ１ｍは第３センサ信号の一例であり、第２磁気センサ１２からのセンサ信号Ｓ２ｐは第２センサ信号の一例である。第２演算部３２Ａは、算出した第２演算信号Ｓｏ２を第３演算部３３に出力する。 So2 = A2 × (S1m−S2p) (46)
That is, the second calculation unit 32A calculates the multiplication of the calculation gain A2 and the subtraction between the sensor signals S1m and S2p. In the present embodiment, the sensor signal S1m from the first magnetic sensor 11A is an example of a third sensor signal, and the sensor signal S2p from the second magnetic sensor 12 is an example of a second sensor signal. The second operation unit 32A outputs the calculated second operation signal So2 to the third operation unit 33.
　第３演算部３３は、第１演算部３１Ａからの第１演算信号Ｓｏ１と第２演算部３２Ａからの第２演算信号Ｓｏ２とに基づき次式（４７）を演算して、電流センサ１Ｃによる検出結果としての出力信号Ｓｏｕｔを生成する。 The third calculation unit 33 calculates the following equation (47) based on the first calculation signal So1 from the first calculation unit 31A and the second calculation signal So2 from the second calculation unit 32A, and the detection by the current sensor 1C The resulting output signal Sout is generated.
Ｓｏｕｔ＝Ａ３×（Ｓｏ１－Ｓｏ２）　　　　　　　　　　　　…（４７）
　　　　＝Ａ３×（Ａ１＋Ａ２）×（ＤＳ１＋ＤＳ２）／２　　…（４７ａ）
　上式（４７）において、Ａ３は第３演算部３３の演算ゲインである。上式（４７ａ）によると、本実施形態に係る電流センサ１Ｃでは、出力信号Ｓｏｕｔにおいて、外部磁場による影響を、２つの磁気センサ１１，１２の信号差ＤＳ１，ＤＳ２間で打ち消すことができる。 Sout = A3 × (So1-So2) (47)
= A3 x (A1 + A2) x (DS1 + DS2) / 2 ... (47a)
In the above equation (47), A3 is the operation gain of the third operation unit 33. According to the above equation (47a), in the current sensor 1C according to this embodiment, in the output signal Sout, the influence of the external magnetic field can be canceled between the signal differences DS1 and DS2 of the two magnetic sensors 11 and 12.
　そこで、本実施形態における調整部４Ｃは、同相磁場Ｂｃに応じた２つの磁気センサ１１，１２の信号差ＤＳ１，ＤＳ２に基づいて、センサゲインＧ１，Ｇ２の少なくとも一方を調整する。本実施形態における電流センサ１Ｃのゲイン調整について、図１８を用いて説明する。 Therefore, the adjustment unit 4C in the present embodiment adjusts at least one of the sensor gains G1 and G2 based on the signal differences DS1 and DS2 of the two magnetic sensors 11 and 12 according to the in-phase magnetic field Bc. The gain adjustment of the current sensor 1C in the present embodiment will be described with reference to FIG.
　図１８（ａ）は、未調整のセンサゲインＧ１，Ｇ２による信号差ＤＳ１，ＤＳ２と同相磁場Ｂｃとの関係を例示するグラフである。図１８（ｂ）は、図１８（ａ）の信号差ＤＳ１，ＤＳ２に対応する出力信号Ｓｏｕｔを示すグラフである。図１８（ｃ）は、図１８（ａ）から調整後の信号差ＤＳ１，ＤＳ２を示すグラフである。図１８（ｄ）は、図１８（ｃ）の信号差ＤＳ１，ＤＳ２に対応する出力信号Ｓｏｕｔを示すグラフである。 FIG. 18A is a graph illustrating the relationship between the signal differences DS1 and DS2 due to the unadjusted sensor gains G1 and G2 and the in-phase magnetic field Bc. FIG. 18B is a graph showing the output signal Sout corresponding to the signal differences DS1 and DS2 of FIG. 18A. FIG. 18 (c) is a graph showing the signal differences DS1, DS2 after adjustment from FIG. 18 (a). FIG. 18 (d) is a graph showing the output signal Sout corresponding to the signal differences DS1, DS2 of FIG. 18 (c).
　図１８（ａ）～（ｄ）のゲイン調整は、例えば図９のステップＳＴ２において、同相磁場Ｂｃを用いて行われる。図１８（ａ）では、センサゲインＧ１，Ｇ２が未調整であることから、双方の信号差ＤＳ１，ＤＳ２のグラフの傾きが異なっている。この際、図１８（ｂ）に示すように、出力信号Ｓｏｕｔは同相磁場Ｂｃに応じて変動している。 The gain adjustment of FIGS. 18A to 18D is performed using the in-phase magnetic field Bc, for example, in step ST2 of FIG. In FIG. 18A, since the sensor gains G1 and G2 are not adjusted, the slopes of the graphs of the signal differences DS1 and DS2 of the both are different. At this time, as shown in FIG. 18B, the output signal Sout fluctuates according to the in-phase magnetic field Bc.
　そこで、本実施形態におけるゲイン調整では、図１８（ａ）に示すように、同相磁場Ｂｃに応じた各々の信号差ＤＳ１，ＤＳ２の変化量ΔＳ１，ΔＳ２が測定される。双方の変化量ΔＳ１，ΔＳ２が適宜、許容誤差の範囲内で合致するように、調整部４ＣにおいてセンサゲインＧ１，Ｇ２の少なくとも一方が調整される。 Therefore, in the gain adjustment in the present embodiment, as shown in FIG. 18A, change amounts ΔS1 and ΔS2 of the signal differences DS1 and DS2 corresponding to the in-phase magnetic field Bc are measured. At least one of the sensor gains G1 and G2 is adjusted in the adjustment unit 4C such that both change amounts ΔS1 and ΔS2 match as appropriate within the range of the tolerance.
　上記の調整により、図１８（ｃ）に示すように、双方の信号差ＤＳ１，ＤＳ２のグラフの傾きを同じにすることができる。これにより、図１８（ｄ）に示すように、同相磁場Ｂｃによっては変動しない出力信号Ｓｏｕｔを得ることができる。よって、本実施形態に係る電流センサ１Ｃにおける外部磁場耐性を確保することができる。 By the above adjustment, as shown in FIG. 18C, the slopes of the graphs of both signal differences DS1 and DS2 can be made the same. As a result, as shown in FIG. 18D, it is possible to obtain an output signal Sout that does not fluctuate due to the in-phase magnetic field Bc. Therefore, the external magnetic field resistance in the current sensor 1C according to the present embodiment can be secured.
　以上の説明では、同相磁場Ｂｃに応じた信号差ＤＳ１，ＤＳ２の変化量ΔＳ１，ΔＳ２を用いてセンサゲインＧ１，Ｇ２の調整が行われる例を説明した。これに限らず、同相磁場Ｂｃに応じた各演算信号Ｓｏ１，Ｓｏ２の変化量や、各演算部３１Ａ，３２Ａへの入力信号の変化量を用いて、センサゲインＧ１，Ｇ２の調整が行われてもよい。 In the above description, the example in which the sensor gains G1 and G2 are adjusted using the change amounts ΔS1 and ΔS2 of the signal differences DS1 and DS2 according to the in-phase magnetic field Bc has been described. The adjustment of the sensor gains G1 and G2 is performed using the change amount of each operation signal So1 and So2 according to the in-phase magnetic field Bc and the change amount of the input signal to each operation unit 31A and 32A. It is also good.
　以上のように、本実施形態に係る電流センサ１Ｃにおいて、第１磁気センサ１１Ａは、センサゲインＧ１を用いてセンサ信号Ｓ１ｐ（第１センサ信号）と、同信号とは差動のセンサ信号Ｓ１ｍ（第３センサ信号）とを生成する。第２磁気センサ１２Ａは、センサゲインＧ２を用いて、センサ信号Ｓ２ｐ（第２センサ信号）と、同信号とは差動のセンサ信号Ｓ２ｍ（第４センサ信号）とをさらに生成する。第１演算部３１Ａは、センサ信号Ｓ１ｐとセンサ信号Ｓ２ｍとを入力する。第２演算部３２Ａは、センサ信号Ｓ２ｐとセンサ信号Ｓ１ｍとを入力する。ゲインを調整する工程（図９のＳＴ２）は、センサゲインＧ１，Ｇ２の少なくとも一方を調整する。これにより、本実施形態に係る電流センサ１Ｃにおいて、外部磁場の影響を低減することができる。 As described above, in the current sensor 1C according to the present embodiment, the first magnetic sensor 11A uses the sensor gain G1 to detect the sensor signal S1p (first sensor signal) and the sensor signal S1m (different from the same signal). And a third sensor signal). The second magnetic sensor 12A further generates a sensor signal S2p (second sensor signal) and a sensor signal S2m (fourth sensor signal) that is differential from the sensor signal S2p (second sensor signal) using the sensor gain G2. The first calculation unit 31A receives the sensor signal S1p and the sensor signal S2m. The second operation unit 32A receives the sensor signal S2p and the sensor signal S1m. The step of adjusting the gain (ST2 in FIG. 9) adjusts at least one of the sensor gains G1 and G2. Thereby, in the current sensor 1C according to the present embodiment, the influence of the external magnetic field can be reduced.
　以上の説明では、調整部４Ｃが図９のステップＳＴ２において用いられる例を説明した。これに限らず、例えば調整部４Ｃは、実施形態３の調整部４Ｂと同様に、温度検出部３４によって検出される温度に応じて動作してもよい。 In the above description, an example in which the adjustment unit 4C is used in step ST2 of FIG. 9 has been described. Not only this but adjustment part 4C may operate according to the temperature detected by temperature detection part 34 like adjustment part 4B of Embodiment 3, for example.
　また、以上の説明において、第１及び第２演算部３１Ａ，３２Ａは、入力する信号間の減算を演算した（式（４５），（４６））。減算の代わりに、第１及び第２演算部３１Ａ，３２Ａは、入力する信号の加算を演算してもよい。この場合、例えば第２磁気センサ１２Ａが各演算部３１Ａ，３２Ａに出力するセンサ信号Ｓ２ｐ，Ｓ２ｍを入れ替えることにより、式（４７ａ）のように出力信号Ｓｏｕｔを得ることができる。 Further, in the above description, the first and second calculation units 31A and 32A calculate the subtraction between the input signals (Equations (45) and (46)). Instead of subtraction, the first and second calculation units 31A and 32A may calculate addition of the input signals. In this case, for example, by replacing the sensor signals S2p and S2m that the second magnetic sensor 12A outputs to the arithmetic units 31A and 32A, the output signal Sout can be obtained as shown in equation (47a).
　また、本実施形態において、第３演算部３３は、式（４７）のような第１及び第２演算信号Ｓｏ１，Ｓｏ２間の減算により、式（４７ａ）のように、第１及び第２磁気センサ１１Ａ，１２Ａの感知結果において同相磁場Ｂｃの影響が打ち消される差動増幅を演算した。第３演算部３３は、第１及び第２演算信号Ｓｏ１，Ｓｏ２を加算してもよい。この場合、例えば第２演算部３２Ａに入力するセンサ信号Ｓ１ｍ，Ｓ２ｐを入れ替えることによって、式（４７ａ）と同じ結果が得られる。即ち、第３演算部３３において、第１及び第２磁気センサ１１Ａ，１２Ａの感知結果の差動増幅を演算することができる。 Further, in the present embodiment, the third operation unit 33 generates the first and second magnetic fields as shown in equation (47a) by subtraction between the first and second operation signals So1 and So2 as shown in equation (47). The differential amplification in which the influence of the in-phase magnetic field Bc is canceled out on the sensing results of the sensors 11A and 12A is calculated. The third operation unit 33 may add the first and second operation signals So1 and So2. In this case, for example, the same result as Expression (47a) can be obtained by interchanging the sensor signals S1m and S2p input to the second arithmetic unit 32A. That is, in the third calculation unit 33, differential amplification of the sensing results of the first and second magnetic sensors 11A and 12A can be calculated.
（他の実施形態）
　上記の各実施形態では、電流センサ１が取り付けられる導体の一例として、図１のバスバー２を説明したが、特にこれに限らず、種々の導体が用いられてもよい。電流センサ１の検出対象の電流が流れる導体の変形例について、図１９～２１を用いて説明する。 (Other embodiments)
In each of the above-described embodiments, the bus bar 2 of FIG. 1 is described as an example of the conductor to which the current sensor 1 is attached. However, the present invention is not limited to this and various conductors may be used. A modification of the conductor through which the current to be detected by the current sensor 1 flows will be described with reference to FIGS.
　図１９は、電流が流れる２つの流路２１，２２を有する導体２Ａの変形例１を示す。図１９（ａ）は、本変形例の導体２Ａの平面図を示している。図１９（ｂ）は、図１９（ａ）の導体２Ａにおいて同相磁場Ｂｃを印加する状態を例示している。 FIG. 19 shows a modification 1 of a conductor 2A having two flow paths 21 and 22 through which current flows. FIG. 19A shows a plan view of a conductor 2A of this modification. FIG. 19B illustrates a state in which the in-phase magnetic field Bc is applied to the conductor 2A of FIG. 19A.
　本変形例の導体２Ａは、長手方向（Ｙ方向）において第１及び第２流路２１，２２が＋Ｙ側の端部で連結しており、－Ｙ側の端部で分離している。図１９（ａ）に示すように、導体２Ａを流れる電流は、第１流路２１を＋Ｙ向きに流れると、＋Ｙ側の端部で迂回することにより、第２流路２２を－Ｙ向きに流れる。電流による信号磁場Ｂ１，Ｂ２は、図１９（ａ）に示すように、例えばＺ方向における導体２Ａの同じ側（例えば＋Ｚ側）で第１流路２１近傍の領域Ｒ１０と、第２流路２２近傍の領域Ｒ２０とにおいて、互いに逆相を有する。 In the conductor 2A of this modification, the first and second flow paths 21 and 22 are connected at the + Y end in the longitudinal direction (Y direction), and are separated at the −Y end. As shown in FIG. 19A, when the current flowing through the conductor 2A flows in the first channel 21 in the + Y direction, the current flowing in the conductor 2A detours at the end on the + Y side, thereby making the second channel 22 in the -Y direction. Flow. As shown in FIG. 19A, for example, the signal magnetic fields B1 and B2 by the current are a region R10 in the vicinity of the first flow passage 21 on the same side (for example, + Z side) of the conductor 2A in the Z direction; The adjacent regions R20 have opposite phases to each other.
　本変形例においては、例えば電流センサ１が導体２Ａに取り付けられた状態において、２つの磁気センサ１１，１２が、それぞれ第１流路２１近傍の領域Ｒ１０と第２流路２２近傍の領域Ｒ２０とに配置される。これにより、本変形例においても、上記各実施形態と同様に、電流センサ１におけるＳ／Ｎ比を良くして電流の検出精度を向上できる。 In the present modification, for example, in a state where the current sensor 1 is attached to the conductor 2A, the two magnetic sensors 11 and 12 are respectively a region R10 near the first flow passage 21 and a region R20 near the second flow passage 22 Will be placed. Thereby, also in the present modification, as in the above embodiments, the S / N ratio in the current sensor 1 can be improved to improve the detection accuracy of the current.
　本変形例の導体２Ａに電流センサ１を取り付けた状態において、同相磁場Ｂｃを用いた調整を行う場合、例えば図１９（ｂ）に示すように、同相磁場Ｂｃを印加する（図９のＳＴ１）。これにより、ゲイン調整（ＳＴ２）等を行える。 When adjustment is performed using the in-phase magnetic field Bc in a state where the current sensor 1 is attached to the conductor 2A of this modification, the in-phase magnetic field Bc is applied as shown in FIG. 19B, for example (ST1 in FIG. 9) . Thereby, gain adjustment (ST2) can be performed.
　図２０は、電流センサ１に検出される電流の流路が１つの導体２Ｂの変形例２を示す。図２０（ａ），（ｂ）は、それぞれＸＺ平面における導体２Ｂの断面図において、各磁気センサ１１，１２の配置例を示している。 FIG. 20 shows a second modification of the conductor 2B in which the flow path of the current detected by the current sensor 1 is one. FIGS. 20A and 20B respectively show arrangement examples of the magnetic sensors 11 and 12 in the cross-sectional view of the conductor 2B in the XZ plane.
　図２０の例では、導体２Ｂの長手方向（Ｙ方向）に電流が流れており、電流による信号磁場Ｂ１は、ＸＺ平面において導体２Ｂの周囲を周回している。信号磁場Ｂ１は、例えば図２０（ａ）に示すように、Ｚ方向における導体２Ｂの＋Ｚ側の領域Ｒ１１と－Ｚ側の領域Ｒ２１とで、互いに逆相を有する。本変形例においては、例えば電流センサ１が導体２Ｂに取り付けられた状態において、２つの磁気センサ１１，１２が、それぞれ＋Ｚ側の領域Ｒ１１と－Ｚ側の領域Ｒ２１とに配置される。この際、各々の磁気センサ１１，１２は、例えば感度軸の方向がＸ方向に適宜、許容誤差の範囲内で平行になるように配置される。 In the example of FIG. 20, the current flows in the longitudinal direction (Y direction) of the conductor 2B, and the signal magnetic field B1 by the current circulates around the conductor 2B in the XZ plane. For example, as shown in FIG. 20A, the signal magnetic field B1 has opposite phases to each other in the region R11 on the + Z side of the conductor 2B in the Z direction and the region R21 on the −Z side. In this modification, for example, in a state where the current sensor 1 is attached to the conductor 2B, the two magnetic sensors 11 and 12 are respectively disposed in the region R11 on the + Z side and the region R21 on the −Z side. Under the present circumstances, each magnetic sensor 11 and 12 is arrange | positioned so that the direction of a sensitivity axis may become parallel in the range of a tolerance | permissible_error suitably in the X direction, for example.
　また、信号磁場Ｂ１は、図２０（ｂ）に示すように、Ｘ方向における導体２Ｂの＋Ｘ側の領域Ｒ１２と－Ｘ側の領域Ｒ２２とにおいても、互いに逆相を有する。２つの磁気センサ１１，１２は、それぞれ＋Ｘ側の領域Ｒ１２と－Ｘ側の領域Ｒ２２とに配置されてもよい。この際、各々の磁気センサ１１，１２は、例えば感度軸の方向がＺ方向に適宜、許容誤差の範囲内で平行になるように配置される。上記の領域Ｒ１１～Ｒ２２に限らず、２つの磁気センサ１１，１２は、導体２Ｂを介して対向し、信号磁場Ｂ１が互いに逆相となる種々の領域に配置可能である。 Further, as shown in FIG. 20 (b), the signal magnetic field B1 has the opposite phase to each other also in the region R12 on the + X side of the conductor 2B in the X direction and the region R22 on the −X side. The two magnetic sensors 11 and 12 may be disposed in the region R12 on the + X side and the region R22 on the −X side, respectively. Under the present circumstances, each magnetic sensor 11 and 12 is arrange | positioned so that the direction of a sensitivity axis may become parallel in the range of a tolerance | permissible_error suitably in Z direction, for example. The two magnetic sensors 11 and 12 are not limited to the above-mentioned regions R11 to R22, and can be arranged in various regions in which the signal magnetic fields B1 have opposite phases with each other via the conductor 2B.
　図２１（ａ），（ｂ）は、それぞれ図２０（ａ），（ｂ）に対応して、変形例２の導体２Ｂにおいて同相磁場Ｂｃを印加する状態を例示している。図２０（ａ），（ｂ）のような磁気センサ１１，１２の配置で同相磁場Ｂｃを用いた調整を行う場合、例えば図２１（ａ），（ｂ）に示すように、同相磁場Ｂｃを印加する（図９のＳＴ１）。図２１（ａ），（ｂ）に限らず、適宜、同相磁場Ｂｃを印加する方向を設定可能である。 FIGS. 21 (a) and 21 (b) illustrate the state in which the in-phase magnetic field Bc is applied to the conductor 2B of the modification 2 corresponding to FIGS. 20 (a) and 20 (b), respectively. When adjustment is performed using the in-phase magnetic field Bc in the arrangement of the magnetic sensors 11 and 12 as shown in FIGS. 20 (a) and 20 (b), for example, as shown in FIGS. 21 (a) and 21 (b) Apply (ST1 in FIG. 9). The direction in which the in-phase magnetic field Bc is applied can be set as appropriate without being limited to FIGS. 21 (a) and 21 (b).
　以上のように、本変形例に係る電流センサ１において、２つの磁気センサ１１，１２は、電流が流れる導体２Ｂを介して対向するように配置される。これによっても、電流センサ１におけるＳ／Ｎ比を良くして電流の検出精度を向上できる。 As described above, in the current sensor 1 according to the present modification, the two magnetic sensors 11 and 12 are arranged to face each other via the conductor 2B through which the current flows. This also makes it possible to improve the detection accuracy of the current by improving the S / N ratio in the current sensor 1.

Claims (9)

  1. 　検出対象の電流によって生じる磁場に基づき前記電流を検出する電流センサの製造方法であって、
    　　磁場を感知する第１磁気センサと、
    　　前記電流に応じて前記第１磁気センサが感知する磁場とは逆相の磁場を感知する第２磁気センサと、
    　　前記第１磁気センサの感知結果と前記第２磁気センサの感知結果との差動増幅を演算して、前記電流の検出結果を示す出力信号を生成する出力部と
    　を備える電流センサを準備する工程と、
    　前記第１磁気センサと前記第２磁気センサとに同相で入力される同相磁場を前記電流センサに印加する工程と、
    　前記同相磁場に応じて、前記第１及び第２磁気センサの感知結果として前記出力部に差動増幅される２つの信号量が合致するように、前記電流センサにおける信号のゲインを調整する工程と
    を含む電流センサの製造方法。     A method of manufacturing a current sensor, which detects the current based on a magnetic field generated by a current to be detected.
    A first magnetic sensor that senses a magnetic field;
    A second magnetic sensor that senses a magnetic field in reverse phase to a magnetic field sensed by the first magnetic sensor according to the current;
    Preparing an electric current sensor comprising: an output unit that calculates differential amplification between the detection result of the first magnetic sensor and the detection result of the second magnetic sensor and generates an output signal indicating the detection result of the current When,
    Applying to the current sensor an in-phase magnetic field input in phase to the first magnetic sensor and the second magnetic sensor;
    Adjusting the gain of the signal in the current sensor such that the amount of two signals differentially amplified at the output as the sensing results of the first and second magnetic sensors match according to the in-phase magnetic field; A method of manufacturing a current sensor, including:
  2. 　前記同相磁場は、均一な空間分布を有する
    請求項１に記載の電流センサの製造方法。     The method of claim 1, wherein the in-phase magnetic field has a uniform spatial distribution.
  3. 　前記第１磁気センサは、第１のセンサゲインにおいて第１センサ信号を生成し、
    　前記第２磁気センサは、第２のセンサゲインにおいて第２センサ信号を生成し、
    　前記出力部は、
    　前記第１センサ信号を入力して、入力した信号に第１の演算ゲインを乗算する第１演算部と、
    　前記第２センサ信号を入力して、入力した信号に第２の演算ゲインを乗算する第２演算部と、
    　前記第１演算部の演算結果と前記第２演算部の演算結果とに基づき前記出力信号を算出する第３演算部とを備え、
    　前記ゲインを調整する工程は、前記第１及び第２のセンサゲイン並びに前記第１及び第２の演算ゲインのうちの少なくとも１つのゲインを調整する
    請求項１又は２に記載の電流センサの製造方法。     The first magnetic sensor generates a first sensor signal at a first sensor gain,
    The second magnetic sensor generates a second sensor signal at a second sensor gain,
    The output unit is
    A first operation unit that receives the first sensor signal and multiplies the input signal by a first operation gain;
    A second operation unit that receives the second sensor signal and multiplies the input signal by a second operation gain;
    A third operation unit that calculates the output signal based on the operation result of the first operation unit and the operation result of the second operation unit;
    The method of manufacturing a current sensor according to claim 1 or 2, wherein the step of adjusting the gain adjusts at least one of the first and second sensor gains and the first and second operation gains. .
  4. 　前記ゲインを調整する工程は、前記第１のセンサゲインと前記第１の演算ゲインの積と、前記第２のセンサゲインと前記第２の演算ゲインの積とが合致するように、前記少なくとも１つのゲインを調整する
    請求項３に記載の電流センサの製造方法。     The step of adjusting the gain may include adjusting the product of the first sensor gain and the first operation gain such that the product of the second sensor gain and the second operation gain matches. 4. A method of manufacturing a current sensor according to claim 3, wherein the gain is adjusted.
  5. 　前記ゲインを調整する工程は、前記第１の演算ゲインと前記第２の演算ゲインの少なくとも一方を調整する
    請求項３又は４に記載の電流センサの製造方法。     5. The method of manufacturing a current sensor according to claim 3, wherein the step of adjusting the gain adjusts at least one of the first operation gain and the second operation gain.
  6. 　前記第１磁気センサは、前記第１のセンサゲインを用いて前記第１センサ信号とは差動の第３センサ信号をさらに生成し、
    　前記第２磁気センサは、前記第２のセンサゲインを用いて前記第２センサ信号とは差動の第４センサ信号をさらに生成し、
    　前記第１演算部は、前記第１センサ信号と前記第４センサ信号とを入力し、
    　前記第２演算部は、前記第２センサ信号と前記第３センサ信号とを入力し、
    　前記ゲインを調整する工程は、前記第１のセンサゲイン及び前記第２のセンサゲインの少なくとも一方を調整する
    請求項３に記載の電流センサの製造方法。     The first magnetic sensor further generates a third sensor signal that is differential from the first sensor signal using the first sensor gain,
    The second magnetic sensor further generates a fourth sensor signal that is differential from the second sensor signal using the second sensor gain,
    The first arithmetic unit inputs the first sensor signal and the fourth sensor signal,
    The second operation unit inputs the second sensor signal and the third sensor signal,
    The method of manufacturing a current sensor according to claim 3, wherein the step of adjusting the gain adjusts at least one of the first sensor gain and the second sensor gain.
  7. 　検出対象の電流によって生じる磁場に基づき前記電流を検出する電流センサであって、
    　第１のセンサゲインにおいて磁場を感知する第１磁気センサと、
    　前記第１磁気センサの感知結果に第１の演算ゲインを乗算する第１演算部と、
    　前記電流に応じて前記第１磁気センサが感知する磁場とは逆相の磁場を、第２のセンサゲインにおいて感知する第２磁気センサと、
    　前記第２磁気センサの感知結果に第２の演算ゲインを乗算する第２演算部と、
    　前記第１及び第２演算部の演算結果に基づき前記電流の検出結果を示す出力信号を算出する第３演算部と、
    　前記第１及び第２のセンサゲイン並びに前記第１及び第２の演算ゲインのうちの少なくとも１つのゲインを調整する調整部とを備え、
    　前記調整部は、前記第１のセンサゲインと前記第１の演算ゲインの積と、前記第２のセンサゲインと前記第２の演算ゲインの積とを合致させる
    電流センサ。     A current sensor that detects the current based on a magnetic field generated by the current to be detected,
    A first magnetic sensor sensing a magnetic field at a first sensor gain;
    A first operation unit that multiplies a first operation gain by the detection result of the first magnetic sensor;
    A second magnetic sensor that senses, at a second sensor gain, a magnetic field opposite in phase to a magnetic field sensed by the first magnetic sensor in response to the current;
    A second operation unit that multiplies a second operation gain by the detection result of the second magnetic sensor;
    A third operation unit that calculates an output signal indicating a detection result of the current based on the operation results of the first and second operation units;
    An adjusting unit configured to adjust at least one of the first and second sensor gains and the first and second operation gains;
    The adjustment unit matches a product of the first sensor gain and the first operation gain with a product of the second sensor gain and the second operation gain.
  8. 　前記調整部は、前記第１磁気センサと前記第２磁気センサとに同相で磁場が入力されたときに、当該磁場に応じて、前記第１演算部の演算結果を示す信号量と前記第２演算部の演算結果を示す信号量とが合致するように、前記少なくとも１つのゲインを調整する
    請求項７に記載の電流センサ。     When the magnetic field is input in the same phase to the first magnetic sensor and the second magnetic sensor, the adjustment unit is configured to generate a signal amount indicating the calculation result of the first calculation unit and the second magnetic field according to the magnetic field. The current sensor according to claim 7, wherein the at least one gain is adjusted such that the amount of signal indicating the calculation result of the calculation unit matches.
  9. 　周囲の温度を検出する温度検出部をさらに備え、
    　前記調整部は、前記温度検出部によって検出される温度に応じて、前記少なくとも１つのゲインを調整する
    請求項７又は８に記載の電流センサ。     It further comprises a temperature detection unit that detects the ambient temperature,
    The current sensor according to claim 7, wherein the adjustment unit adjusts the at least one gain in accordance with a temperature detected by the temperature detection unit.
PCT/JP2018/017864 2017-10-04 2018-05-09 Current sensor and method for manufacturing current sensor WO2019069499A1 (en)

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