JP2004245597A - Current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current sensor capable of accurately measuring current with a same configuration at all times and having the degree of freedom for the installation position of a current wire to be measured. <P>SOLUTION: An MI element 3 is covered by a current sensor substrate 10. When the current sensor is installed so that a current wire 50 to be measured is passed through a through hole 15 in the current sensor substrate 10, a current flowing through the current wire 50 to be measured can be measured with an induced voltage detected by a detection circuit 7 to accurately measure the current with the same configuration at all times. Since a detection coil 5 is formed of a coil pattern in which an inductive through hole 17 formed in the current sensor substrate 10 to an inductive pattern 18, the detection coil 5 can be manufactured by using a semiconductor process technology. Accordingly, the detection coil 5 completely symmetrical with respect to the axal direction of the MI element 3 is easily manufactured and, therefore, the current sensor having high measurement accuracy and a uniform measurement accuracy can be manufactured. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a current sensor using a magneto-sensitive element utilizing a magnetic impedance effect.
[0002]
[Prior art]
Conventionally, as a current sensor for detecting a magnetic flux generated by a measured current with a magnetic sensor having a magnetic impedance effect, an absolute value of a magnetic sensor output is equal to a magnetic flux generated by a measured current and a polarity of the magnetic sensor output is used. There is a type in which two magnetic sensors are arranged at positions where the directions are reversed, and the difference between the outputs of the two magnetic sensors is detected. Further, two magnetic sensors are arranged at positions where the absolute value of the magnetic sensor output is equal to the magnetic flux generated by the measured current and the polarity of the magnetic sensor output is the same, and the sum of the two magnetic sensor outputs is provided. (See, for example, Patent Document 1 below).
Other current sensors that detect a magnetic flux generated by a measured current with a magnetic sensor having a magneto-impedance effect include, for example, the following Patent Document 2 and Non-Patent Document 1.
[0003]
[Patent Document 1]
JP 2002-243766 A [Patent Document 2]
JP 2000-258517 [Non-Patent Document 1]
Colpitts self-oscillation type high-sensitivity and high-speed response current sensor using amorphous magnetic wire MI element "Journal of the Japan Society of Applied Magnetics 20, 629-632 (1996) Kenichi Takeshida and Yoshinori Mouri"
[0004]
[Problems to be solved by the invention]
Since the conventional current sensor is configured as described above, two magnetic sensors are used to improve measurement accuracy when there is a uniform external magnetic field and when current lines are arranged adjacently. Had to be relocated. In addition, when there is a uniform external magnetic field, two magnetic sensors must be disposed at target positions with respect to the current line to be measured. Was.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a current sensor that can always perform high-accuracy current measurement with the same configuration and has a high degree of freedom in the installation position of a current line to be measured is obtained. The purpose is to:
[0006]
[Means for Solving the Problems]
A current sensor according to the present invention includes a current sensor substrate provided with a through-hole at the center of a substantially annular magnetic sensor element so as to cover the magnetic sensor element, and a conductive pattern and a conductive pattern formed on the current sensor substrate. And a coil pattern forming a detection coil by connecting through holes.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
Embodiment 1 FIG.
FIG. 1 is a perspective view showing a configuration outline of a current sensor according to Embodiment 1 of the present invention. In the figure, a zero magnetostrictive amorphous wire (magnetic sensing element) 1 constituting a current sensor is formed in a substantially annular shape. It is installed so as to go around the current line to be measured 50 at least once. At this time, it is desirable that both ends of the zero magnetostrictive amorphous wire 1 are formed as close as possible to minimize the gap. Electrode portions 2 are connected to both ends of the zero magnetostrictive amorphous wire 1 by soldering or the like, and the zero magnetostrictive amorphous wire 1 and the electrode portion 2 constitute an MI (Magneto Impedance) element 3 having electrodes formed thereon.
Meanwhile, there is a magneto-impedance effect (hereinafter, referred to as MI effect) as a new sensing function of a magnetic body. The MI effect is obtained by applying a pulse current or a high-frequency current from one end of the electrode portion 2 of the MI element 3 made of a magnetic material such as a zero magnetostrictive amorphous wire 1 to the current line 50 to be measured by using the skin effect. This is a magnetic phenomenon in which the impedance of the zero magnetostrictive amorphous wire 1 changes sensitively to an external magnetic field generated by a flowing current to be measured.
In the current sensor according to the first embodiment, the zero magnetostrictive amorphous wire 1 is formed in a substantially annular shape, and is installed at least once around the measured current line 50. The current value flowing through the current line under measurement 50 is detected by detecting an external magnetic field generated when the current flows.
[0008]
FIG. 2 is a circuit diagram showing a current sensor according to the first embodiment of the present invention. In the figure, a power supply V _dd , resistors R _{1 to} R ₄ , capacitors C _{1 to} C ₃ , and CMOS inverters Q _{1 to} Q _{6 are used} . A power supply circuit 4 for generating a pulsed current is formed.
The resistor R ₄ of the power supply circuit 4 is connected to the electrode 2 at one end of the MI element 3, the pulse current generated by the power supply circuit 4 is supplied, and the electrode 2 at the other end of the MI element 3 is grounded. I have. A feedback coil 6 is wound around the MI element 3 together with the detection coil 5.
Analog switch SW, the resistor _R 5 to R _7, a capacitor _{C 4,} the amplifier amp, constitute a detection circuit 7 for detecting an induced voltage generated in the detection coil 5, also, the output terminal out of the amplifier amp resistor _{R 8} Is connected to one end of the feedback coil 6, and the other end of the feedback coil 6 is grounded.
As shown in FIG. 2, the current sensor according to the first embodiment uses the MI element 3 as a head and supplies a pulsed current having a rise time of about 5 ns generated by a power supply circuit 4 including a CMOS multivibrator and a CR differentiating circuit. It is configured to be applied to the MI element 3 and detect an induced voltage of the detection coil 5 wound around the MI element 3 (for example, 40 turns).
The zero magnetostrictive amorphous wire 1 is a wire that has strictly a slight negative magnetostriction (−10 ⁻⁷ ) and anisotropy is induced in the circumferential direction by tension annealing. Therefore, when the external magnetic field generated by current application in the wire length direction is 0, the change in magnetic flux due to the pulsed current of the 0 magnetostrictive amorphous wire 1 is only in the circumferential direction, and in the circumferential direction of the 0 magnetostrictive amorphous wire 1 Is zero, and the induced voltage of the detection coil 5 is zero.
When an external magnetic field is applied, the magnetization vector of the 0 magnetostrictive amorphous wire 1 is inclined in the wire axis direction, and the magnetization vector is rotated in the circumferential direction by the circumferential magnetic field generated by the pulsed current. At this time, the component of the magnetic flux change in the wire axis direction interlinks with the detection coil 5, and an induced voltage is generated in the detection coil 5. The sign of the induced voltage of the detection coil 5 is opposite to the sign of the external magnetic field. In the zero magnetostrictive amorphous wire 1, the movement of the domain wall is suppressed due to the skin effect, and only the rotation of the magnetization vector occurs. Due to this magnetization operation, the induced voltage of the detection coil 5 in this circuit configuration becomes a voltage proportional to the external magnetic field without applying a bias magnetic field, and represents the characteristics of the linear magnetic field sensor.
However, the induced voltage waveform is not a pure pulse voltage waveform, but an LC oscillation waveform due to the stray capacitance of the detection coil 5 because of the rapid change of the linkage magnetic flux due to the steep pulse current. Since only the first pulse waveform of this vibration waveform changes with high sensitivity in proportion to the external magnetic field, it is necessary to extract only the first pulse waveform in order to configure a high-sensitivity magnetic field sensor. Here, only the first pulse waveform is extracted by the analog switch SW.
Trigger pulse of the analog switch SW, should the phase advance from 0 pulse current supplied magnetostrictive amorphous wire 1, the pulse energizing current is to be delayed about 10ns through two CMOS inverters Q _3, Q _4.
The height of the first pulse waveform of the induced voltage of the detection coil 5, resistors R _5, is converted into a DC voltage by the peak hold circuit comprising a capacitor C _4, a sensor output voltage amplifier # 038. This sensor output voltage has a value corresponding to the measured current flowing through the measured current line 50. A current proportional to the sensor output voltage is applied to the feedback coil 6 to generate a negative feedback magnetic field that cancels an external magnetic field. Due to this negative feedback effect, sensor characteristics with good linearity and no hysteresis can be obtained.
[0009]
3 is a perspective view showing the configuration of the current sensor according to Embodiment 1 of the present invention, FIG. 4 is a front view showing the current sensor, FIG. 5 is a cross-sectional view showing the current sensor, and FIG. FIG. In the first embodiment, the current sensor is formed as a current sensor substrate 10.
The configuration of the current sensor substrate 10 will be described. In FIG. 3, for example, a wire installation groove 13 is formed in a lower substrate 11 that is easily thinned, such as silicon, glass, or a printed circuit board. If the lower substrate 11 is silicon or glass, the wire installation groove 13 can be manufactured with high precision by etching or the like.
Electrodes 2 made of, for example, copper foil are formed at both ends of the wire installation groove 13. Although not shown in FIG. 3, a circuit board 14 on which a processing circuit as shown in FIG. Wiring for connection is also formed (FIGS. 4, 5: Wiring 16). These are easily formed with high precision by a semiconductor process such as a vapor deposition technique such as sputtering. After the 0 magnetostrictive amorphous wire 1 is set in the wire setting groove 13 and connected to the electrode portion 2 by soldering or conductive paste to form the MI element 3, the lower substrate 11 and the upper substrate 12 are joined, and the current sensor The substrate 10 is manufactured.
The MI element 3 is preferably fixed in contact with the lower substrate 11 and the upper substrate 12 so as not to apply stress, and may be fixed with an adhesive or the like before joining the substrates. For example, as shown in FIG. 6, a plurality of wire installation stands 19 are used to fix between the lower substrate 11 and the upper substrate 12 with the smallest possible contact area. The space other than the wire installation table 19 may be a gas, may be filled with a resin having good fluidity, and may be in a state where no stress is applied to the MI element 3. The lower substrate 11 and the upper substrate 12 can be easily manufactured by a process such as direct bonding or anodic bonding if it is made of silicon or glass.
In the current sensor substrate 10, a through hole 15 is provided at the center of the substantially annular MI element 3 for allowing the electric wire 50 to penetrate. When connecting the MI element 3 and the circuit board 14, though not shown, a through-hole may be formed in the upper substrate 12 and taken out, or the connection may be made from the end face of the substrate. Although the wire installation groove 13 is provided only in the lower substrate 11 in the drawing, the wire installation groove 13 may be provided in the upper substrate 12 as well. Further, if silicon is used for the lower substrate 11 or the upper substrate 12, the circuit substrate 14 on which the processing circuit as shown in FIG. 2 is mounted can be formed on the same substrate.
The detection coil 5 and the feedback coil 6 are produced so as to surround the MI element 3. 4 and 5 show only one coil for simplicity. Both coils are configured by continuously connecting a conductive through hole 17 penetrating the front and back surfaces of the current sensor substrate 10 and a conductive pattern 18 formed on the front and back surfaces of the current sensor substrate 10. Both coils are preferably installed as close to the MI element 3 as possible. In this configuration, since the detection coil 5 and the feedback coil 6 can be manufactured using the semiconductor process technology, it is possible to easily manufacture a coil that is completely symmetrical in the axial direction of the MI element 3.
The production of the detection coil 5 and the feedback coil 6 is not limited to the first embodiment. For example, the enamel wire or the like is wound around the MI element 3 by a conventional winding technique, and the detection coil 5 and the feedback coil 6 are formed. The feedback coil 6 may be configured. Further, since the MI element 3 is annular, the measurement accuracy is not affected no matter where the current line to be measured 50 is installed inside the annular MI element 3.
[0010]
As described above, according to the first embodiment, the MI element 3 is covered by the current sensor substrate 10, and the current sensor is configured such that the measured current line 50 passes through the through hole 15 of the current sensor substrate 10. Is provided, the current flowing through the measured current line 50 can be measured by the induced voltage detected by the detection circuit 7, so that highly accurate current measurement can always be performed with the same configuration.
Also, since the MI element 3 is formed in a substantially annular shape, the measured current line 50 can be placed anywhere within the annular shape without being affected by the measurement accuracy. A current sensor having a degree of freedom in the installation position can be manufactured.
Further, since the detection coil 5 and the feedback coil 6 are formed by a coil pattern formed by connecting the conductive through hole 17 and the conductive pattern 18 formed on the current sensor substrate 10, the detection coil 5 and the feedback coil 6 are formed using a semiconductor process technology. Since the feedback coil 6 can be manufactured, the detection coil 5 and the feedback coil 6 that are completely symmetric in the axial direction of the MI element 3 can be easily manufactured. As a result, a current sensor having high measurement accuracy and uniform measurement accuracy can be obtained. Can be manufactured.
[0011]
Embodiment 2 FIG.
FIG. 7 is a perspective view showing a configuration outline of a current sensor according to Embodiment 2 of the present invention. In the figure, a zero magnetostrictive amorphous wire (first magnetosensitive element) 1a is formed in a substantially annular shape, and is measured. It is installed so as to go around the current line 50 at least once. Similarly, the zero magnetostrictive amorphous wire (second magnetosensitive element) 1b is formed in a substantially annular shape and is arranged so as to overlap the zero magnetostrictive amorphous wire 1a. Electrode portions 2 are connected to both ends of the zero magnetostrictive amorphous wires 1a and 1b, and the zero magnetostrictive amorphous wires 1a and 1b and the electrode portion 2 constitute MI elements 3a and 3b having electrodes formed thereon.
In the current sensor according to the second embodiment, two zero magnetostrictive amorphous wires 1a and 1b are formed in a substantially annular shape, and each of the current sensors 50 is wrapped at least once around the current line 50 to be measured. The current value flowing through the measured current line 50 is detected by detecting an external magnetic field generated when the measured current flows through the line 50.
[0012]
Figure 8 is a circuit diagram showing a current sensor according to a second embodiment of the present invention. In the figure, the power supply circuit 21, the resistor _{R 4} is deleted, added CMOS inverter _{Q 7} is pulse MI elements 3a, 3b, It is the same as the power supply circuit 4 shown in FIG.
The CMOS inverters Q ₆ and Q ₇ of the power supply circuit 21 are respectively connected to the electrode portions 2 at one ends of the MI elements 3a and 3b, and the pulse conduction current generated by the power supply circuit 4 is supplied to the CMOS inverters Q ₆ and Q _7. The end electrode portions 2 are commonly grounded. A feedback coil 6a is wound around the MI element 3a together with the detection coil (first detection coil) 5a, and a feedback coil 6b is wound around the MI element 3b together with the detection coil (second detection coil) 5b. I have.
Analog switches SW1, SW2, resistor _R 4 to R _7, a capacitor _C 4, _{C 5,} the amplifier # 038, detection for detecting the induced voltage obtained by adding the induced voltage generated in the detection coil 5b on the induced voltage generated in the detection coils 5a constitute a circuit 22, also to the output terminal out of the amplifier amp is connected to one end of the feedback coil 6b via a resistor R _8, the other end of the feedback coil 6b is connected to one end of the feedback coil 6a, feedback coil 6a Is grounded.
As shown in FIG. 8, in the current sensor according to the second embodiment, the induced voltage detected by detection circuit 22 is obtained by adding an induced voltage generated in detection coil 5b to an induced voltage generated in detection coil 5a. Since the voltage is a voltage, a more reliable current measurement can be performed as compared with a current sensor that detects an induced voltage generated in one detection coil. Furthermore, common mode noise acting simultaneously on the two 0 magnetostrictive amorphous wires 1a and 1b can be canceled out, and a highly reliable current measurement can be performed even when there is electromagnetic field noise.
[0013]
FIG. 9 is a perspective view showing a configuration of a current sensor according to Embodiment 2 of the present invention. In the figure, a current sensor substrate (first current sensor substrate) 10a is, as shown in FIG. The through-hole 15 is formed at the center of the substantially annular zero magnetostrictive amorphous wire 1a so as to cover the wire 1a, and the current sensor substrate (second current sensor substrate) 10b is also It is formed so as to cover the magnetostrictive amorphous wire 1b, and the through hole 15 is provided at the center of the substantially annular zero magnetostrictive amorphous wire 1b. The current sensor substrates 10a and 10b are arranged so as to overlap each other. They are connected by an adhesive or the like.
As shown in FIG. 5, the current sensor substrate 10a has a detection coil and a feedback coil formed by the connection of the conductive through hole 17 and the conductive pattern 18, and the current sensor substrate 10b similarly has the conductive through hole 17 The detection coil and the feedback coil are configured by the connection of the conductive pattern 18.
The circuit board 14 on which the processing circuit as shown in FIG. 8 is mounted may be installed on any one of the current sensor boards 10a and 10b, and may be mounted on the two current sensor boards 10a and 10b, respectively. It may be divided and installed.
[0014]
As described above, according to the second embodiment, the current sensor is formed such that the current line 50 to be measured penetrates the ring of the MI elements 3a and 3b which are formed in a substantially ring shape and are arranged so as to overlap with each other. Is provided, the current flowing through the measured current line 50 can be measured by the induced voltage detected by the detection circuit 22, and highly accurate current measurement can always be performed with the same configuration.
Also, since the MI elements 3a and 3b are formed in a substantially annular shape, the measured current line 50 can be installed anywhere in the annular shape without being affected by the measurement accuracy. A current sensor having a degree of freedom at 50 installation positions can be obtained.
Further, since the induced voltage detected by the detection circuit 22 is an induced voltage obtained by adding the induced voltage generated in the detection coil 5b to the induced voltage generated in the detection coil 5a, a current for detecting the induced voltage generated in one detection coil is used. Current measurement with higher reliability than a sensor can be performed. Further, electromagnetic noise (common mode noise) acting simultaneously on the MI elements 3a and 3b can be canceled out, and even if there is electromagnetic noise, highly reliable current measurement can be performed.
Further, the MI element 3a is covered by the current sensor substrate 10a, and the MI element 3b is covered by the current sensor substrate 10b, and the current line 50 to be measured is placed in the through hole 15 of the current sensor substrates 10a and 10b arranged so as to overlap each other. If a current sensor is provided so as to penetrate, the current flowing through the current line to be measured 50 can be measured by the induced voltage detected by the detection circuit 22, and a highly accurate current measurement is always performed with the same configuration. be able to.
Further, the detection coils 5a and 5b and the feedback coils 6a and 6b are formed by first and second coil patterns formed by connecting the conductive through holes 17 and the conductive patterns 18 formed on the current sensor substrates 10a and 10b, respectively. Therefore, since the detection coils 5a and 5b and the feedback coils 6a and 6b can be manufactured by using the semiconductor process technology, the detection coils 5a and 5b and the feedback coils 6a and 6b that are completely symmetrical in the axial direction of the MI elements 3a and 3b are used. The current sensor can be easily manufactured, and as a result, a current sensor with high measurement accuracy and uniform measurement accuracy can be manufactured.
[0015]
Embodiment 3 FIG.
FIG. 10 is a cross-sectional view showing a current sensor substrate according to Embodiment 3 of the present invention. In the figure, an electromagnetic field shield layer 32 electrically grounded around current sensor substrate 10 via insulating layer 31 is shown. Is formed.
The electromagnetic field shield layer 32 and the insulating layer 31 are formed of, for example, a thin film or the like, and other configurations are the same as those of the other embodiments. Since the current sensor substrate 10 is thus surrounded by the electromagnetic field shield layer 32, noise generated in the MI element 3 and the processing circuit due to an external electromagnetic field can be suppressed.
[0016]
As described above, according to the third embodiment, by forming the electromagnetic field shield layer 32, it is possible to suppress noise generated in the MI element 3 and the processing circuit due to an external electromagnetic field, thereby achieving high precision. A current sensor can be manufactured.
[0017]
【The invention's effect】
As described above, according to the present invention, if the magnetic sensor is covered with the current sensor substrate, and the current sensor is provided so that the current line to be measured passes through the through hole of the current sensor substrate, the current sensor substrate can be covered. The current flowing through the measurement current line can be measured by the induced voltage detected by the detection circuit, and highly accurate current measurement can always be performed with the same configuration.
In addition, since the magneto-sensitive element is formed in a substantially annular shape, the current line to be measured can be installed anywhere within the annular shape without being affected by the measurement accuracy. A current sensor having a high degree of freedom can be manufactured.
Furthermore, since the detection coil is constituted by a conductive pattern formed on the current sensor substrate and a coil pattern formed by connecting conductive through holes, the detection coil can be manufactured using a semiconductor process technology. A detection coil completely symmetric in the direction can be easily manufactured, and as a result, there is an effect that a current sensor with high measurement accuracy and uniform measurement accuracy can be manufactured.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of a current sensor according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing a current sensor according to Embodiment 1 of the present invention.
FIG. 3 is a perspective view showing a configuration of a current sensor according to Embodiment 1 of the present invention.
FIG. 4 is a front view showing a current sensor.
FIG. 5 is a sectional view showing a current sensor.
FIG. 6 is a perspective view showing details of installation of a 0 magnetostrictive amorphous wire.
FIG. 7 is a perspective view illustrating a schematic configuration of a current sensor according to a second embodiment of the present invention.
FIG. 8 is a circuit diagram showing a current sensor according to a second embodiment of the present invention.
FIG. 9 is a perspective view showing a configuration of a current sensor according to Embodiment 2 of the present invention.
FIG. 10 is a sectional view showing a current sensor board according to Embodiment 3 of the present invention.
[Explanation of symbols]
10 magnetostrictive amorphous wire (magnetic sensing element), 1a 0 magnetostrictive amorphous wire (first magnetosensitive element), 1b 0 magnetostrictive amorphous wire (second magnetosensitive element), 2 electrodes, 3, 3a, 3b MI element , 4,21 power supply circuit, 5 detection coil, 5a detection coil (first detection coil), 5b detection coil (second detection coil), 6, 6a, 6b feedback coil, 7, 22 detection circuit, 10 current sensor Substrate, 10a Current sensor substrate (first current sensor substrate), 10b Current sensor substrate (second current sensor substrate), 11 lower substrate, 12 upper substrate, 13 wire installation groove, 14 circuit substrate, 15 through hole, 16 wiring, 17 conductive through-hole, 18 conductive patterns, 19 wire installation base, 31 an insulating layer, 32 electromagnetic shield layer, 50 the current to be measured line, # 038 _amplifier, C 1 -C Capacitor, out the output _terminals, Q ₁ ~Q 7 CMOS _inverters, R 1 to R ₈ resistors, SW, SW1, SW2 analog _{switch, V dd} supply.

Claims (5)

A power supply circuit for generating a pulse current or a high-frequency current;
A magneto-sensitive element that is formed in a substantially annular shape, and that receives a pulse current or a high-frequency current generated by the power supply circuit from one end and changes impedance according to an external magnetic field;
A detection coil wound around the magneto-sensitive element,
A detection circuit for detecting an induced voltage generated in the detection coil,
A current sensor substrate formed so as to cover the magneto-sensitive element, and having a through hole provided in the center of the substantially annular magneto-sensitive element;
A current sensor, comprising: a coil pattern formed on the current sensor substrate and forming the detection coil by connecting a conductive pattern and a conductive through hole. A power supply circuit for generating a pulse current or a high-frequency current;
A first magneto-sensitive element that is formed in a substantially annular shape and that receives a pulse current or a high-frequency current generated by the power supply circuit from one end and changes impedance according to an external magnetic field;
A pulse current or a high-frequency current generated by the power supply circuit is applied from one end and is formed in a substantially annular shape and arranged so as to overlap the first magneto-sensitive element, and changes impedance according to an external magnetic field. A second magneto-sensitive element;
A first detection coil wound around the first magnetic sensing element;
A second detection coil wound around the second magnetic sensing element;
A current sensor, comprising: a detection circuit that detects an induced voltage obtained by adding an induced voltage generated in the second detection coil to an induced voltage generated in the first detection coil. A first current sensor substrate formed so as to cover the first magneto-sensitive element, and having a through-hole provided at the center of the substantially annular first magneto-sensitive element;
A second current sensor substrate formed so as to cover the second magneto-sensitive element and having a through-hole provided in the center of the substantially annular second magneto-sensitive element;
A first coil pattern formed on the first current sensor substrate and forming a first detection coil by connecting a conductive pattern and a conductive through hole;
A second coil pattern formed on the second current sensor substrate and forming a second detection coil by connecting the conductive pattern and the conductive through hole;
The current sensor according to claim 2, wherein the first current sensor substrate and the second current sensor substrate are arranged so as to overlap with each other. 4. The current sensor according to claim 1, wherein an amorphous wire made of an amorphous magnetic material is used as the magneto-sensitive element. The current sensor according to any one of claims 1 to 4, wherein an electromagnetic field shield layer is formed around the current sensor substrate.

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