JP2016206173A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire a low profile current detector.SOLUTION: A current detector is mountable onto a circuit board 101 in which a flux gate type magnetic sensor IC chip 111 that detects a magnetic flux for current detection is implemented and includes an almost annular core 4 that forms a magnetic path for a magnetic flux induced by the current of a detection object. The core 4 is arranged in a direction almost in parallel to the circuit board 101 when the current detector is mounted onto the board 101 and includes a gap 41 at a portion located on or on the upper side of the magnetic sensor IC chip 111 in a magnetic path by the core 4 when the current detector is mounted onto the board 101.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a current detection device.

  A magnetic balance type current sensor has a vertical (that is, vertical) annular core, a primary conductor is arranged so as to be linked to the annular core, and a correction coil (secondary coil) is installed on the annular core. Furthermore, a cavity is provided at the bottom of the annular core, a rod-shaped fluxgate sensor core is inserted into the cavity, and a control board for driving the sensor core is a board on which the current sensor is mounted. And is connected to the sensor core (see, for example, Patent Document 1).

  On the other hand, as a flux gate type magnetic sensor, there is an IC chip sensor incorporating a circuit configuration as described in Patent Document 2, for example, in addition to the rod-shaped sensor for special applications as described above.

Special table 2011-510318 gazette US Patent Application Publication No. 2014/0218018

  However, since the above-described current sensor uses a vertical annular core, it has a high profile, and when this current sensor is installed on the board, it is adjusted to the height of the current sensor above the board. Space is required.

  The present invention has been made in view of the above problems, and an object thereof is to obtain a low-profile current detection device.

  A current detection device according to the present invention is a current detection device that can be mounted on a substrate on which a fluxgate type magnetic sensor IC chip for detecting magnetic flux for current detection is mounted, and is induced by a current to be detected. A substantially annular core that forms a magnetic path for the magnetic flux is provided. The core is arranged in a direction substantially parallel to the substrate when the current detection device is mounted on the substrate, and the magnetic sensor IC chip is placed on the magnetic path when the current detection device is mounted on the substrate. Or it has a gap in the location located above.

  According to the present invention, a low current detector can be obtained.

FIG. 1 is a perspective view showing a current detection device according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the bottom surface of the current detection device according to Embodiment 1 of the present invention. FIG. 3 is a perspective view showing an inner surface of the upper case member in FIG. 1. FIG. 4 is a perspective view illustrating a state where the upper case member and the primary conductor are removed from the current detection device illustrated in FIG. 1. FIG. 5 is a perspective view showing the core 4 and the correction coil 6 of the current detection device shown in FIG. FIG. 6 is a perspective view showing an example of a circuit board to which the current detection device according to Embodiment 1 is attached. FIG. 7 is a side view showing the current detection device according to Embodiment 1 in a state of being mounted on the circuit board 101. FIG. 8 is a diagram illustrating a current detection operation of the current detection device according to the first embodiment. FIG. 9 is a perspective view showing the core of the current detection device according to Embodiment 3 of the present invention. FIG. 10 is a side view showing an example of the core of the current detection device according to Embodiment 4 of the present invention. FIG. 11 is a perspective view showing a state where the upper case member and the primary conductor are removed from the current detection device according to the fifth embodiment. FIG. 12 is a perspective view showing a state where the upper case member, the lower case member, and the primary conductor are removed from the current detection device according to the fifth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.

  FIG. 1 is a perspective view showing a current detection device according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing the bottom surface of the current detection device according to Embodiment 1 of the present invention. FIG. 3 is a perspective view showing an inner surface of the upper case member in FIG. 1. FIG. 4 is a perspective view illustrating a state where the upper case member and the primary conductor are removed from the current detection device illustrated in FIG. 1.

  The current detection device according to the first embodiment is a current detection device that can be mounted on a substrate on which a fluxgate type magnetic sensor IC chip that detects magnetic flux for current detection is mounted.

  As shown in FIGS. 1 and 2, the current detection device according to the first embodiment includes an upper case member 1 and a lower case member 2. The upper case member 1 has a groove 11 continuous on its upper surface and one side surface. The primary conductor 3 is disposed in the groove 11.

  As shown in FIG. 1, the upper case member 1 is attached to the lower case member 2. Thereby, the upper case member 1 and the lower case member 2 are integrated to form a case. As shown in FIG. 2, the upper case member 1 is fixed to the lower case member 2 by fitting the claw portions 12 at the tips of the two opposite sides of the upper case member 1 into the lower case member 2.

  The primary conductor 3 is a metal member that conducts the current Ip to be detected. In FIG. 1, there are four primary conductors 3, but one may be used, and the number may be as required. Further, the primary conductor 3 may be a bus bar.

  As shown in FIG. 3, the upper case member 1 has guide convex portions 13 standing upright from the top surface, and the guide convex portions 13 have the same number of guide holes 14 as the grooves 11. The guide hole 14 is formed so as to be continuous with the groove 11, and the primary conductor 3 is disposed along the groove 11 and the guide hole 14.

  Further, as shown in FIG. 4, the core 4 to which the correction coil 6 is attached by the bobbin 5 is fixed inside the lower case member 2. The correction coil 6 is wound around the bobbin 5. The lower case member 2 includes a substantially rectangular flat plate-like bottom surface portion 2a and four substantially flat plate-shaped side surface portions 2b extending upright from the bottom surface portion 2a. The core 4 on which the bobbin 5 and the correction coil 6 are mounted is fitted between the side surface portions 2 b, arranged substantially parallel to the bottom surface portion 2 a of the lower case member 2, and fixed to the lower case member 2.

  In the first embodiment, the core 4 is directly fixed to the lower case member 2, but the core 4 may be indirectly fixed to the lower case member 2 using another attachment member. The core 4 may be fixed to the lower case member 2 with an adhesive.

  FIG. 5 is a perspective view showing the core 4 and the correction coil 6 of the current detection device shown in FIG.

  The core 4 is a substantially annular core that forms a magnetic path for the magnetic flux Tp induced by the current Ip to be detected. In this embodiment, the core 4 includes a plurality of core members 4a and 4b which are UU cores. There is a gap 41 between one end face of the core member 4a and one end face of the core member 4b, and the other end face of the core member 4a and the other end face of the core member 4b are joined to each other.

  The two end faces constituting the gap 41 in the core 4 are formed substantially perpendicular to the magnetic path formed by the core 4, and as a result, are substantially perpendicular to the bottom surface portion 2 a of the lower case member 2.

  In addition, one leg portion of the core members 4 a and 4 b forming the gap 41 has a protruding portion 42 that protrudes downward (to the bottom surface side), and a notch portion 43 that has substantially the same shape as the protruding portion 42.

  In Embodiment 1, the width H1 in the height direction of the other leg portion of the core members 4a and 4b having the joint surfaces is narrower than the width H2 of the other portions of the core members 4a and 4b. Thus, when the bobbin 5 and the correction coil 6 are mounted on the core 4, the bottom surfaces of the bobbin 5 and the correction coil 6 do not protrude from the bottom surface of the core 4, which contributes to the low profile of the current detection device. doing.

  The width H1 in the height direction of the other leg portion of the core members 4a and 4b having the joint surfaces may be the same as the width H2 of the other portion. In this case, for example, the protrusion height H3 of the protrusion 42 may be increased according to the protrusion height of the bobbin 5 and the correction coil 6 from the bottom surface of the core 4.

  In this embodiment, the core 4 is a ferrite core. As shown in FIG. 5, since the shape of the core 4 is not complicated, the core members 4a and 4b can be easily manufactured from a ferrite material. As this ferrite material, an Mn—Zn based ferrite material, an Ni—Zn based ferrite material or the like can be used, and an Mn—Zn based ferrite material is preferable in terms of magnetic permeability. Note that the magnetic material of the core 4 is not limited to the ferrite material.

  For example, when a complicated core shape is required, such as the core described in Patent Document 1 (Japanese Patent Publication No. 2011-510318), it is necessary to use an expensive material with good workability such as permalloy or amorphous alloy. Is done. On the other hand, in this embodiment, the current detection device can be manufactured at low cost by using the core 4 as a ferrite core. In the case of a ferrite core, the magnetic flux density is non-linear with respect to the strength of the magnetic field (that is, the current to be detected), but by detecting the current using a magnetic balance method, The magnetic flux density becomes small and is not particularly problematic.

  The core 4 is a substantially annular core that forms a magnetic path for the magnetic flux Tp induced by the current Ip to be detected. In this embodiment, the core 4 includes a plurality of core members 4a and 4b which are UU cores. There is a gap 41 between one end face of the core member 4a and one end face of the core member 4b, and the other end face of the core member 4a and the other end face of the core member 4b are joined to each other.

  The bobbin 5 is a resin bobbin and includes terminals 51, 52, 53, and 54 that are electrically connected to the correction coil 6. The terminals 51 and 53 are electrically connected to one end of the correction coil 6, and the terminals 52 and 54 are electrically connected to the other end of the correction coil 6. The bobbin 5 has an opening 55, and one leg of each of the core members 4 a and 4 b is inserted into the opening 55, and the correction coil 6 is attached to the core 4.

  In order to detect the current by the magnetic balance method, the correction coil 6 induces a magnetic flux Tc in the core 4 for canceling out the magnetic flux Tp induced in the core 4 by the current Ip of the primary conductor 3. The correction coil 6 induces a magnetic flux Tc in the core 4 by a current input using the terminals 51 to 54.

  Further, as shown in FIG. 2, the lower case member 2 has a fixing protrusion 21 for fixing the current detection device to a circuit board described later. That is, the lower case member 2 functions as a support member that supports the core 4 and can be attached to the circuit board. Further, the lower case member 2 has an opening 22 below the position where the gap 41 of the core 4 is disposed. Thereby, the periphery of the gap 41 of the core 4 is exposed by the opening 22. As shown in FIG. 4, the lower case member 2 has a guide tube 23 that stands upright from the inner bottom surface thereof. The hollow portion of the guide tube 23 passes through the bottom surface portion 2 a of the lower case member 2, and when the upper case member 1 is attached to the lower case member 2, the guide convex portion 13 of the upper case member 1 The tip of the guide protrusion 13 is exposed as shown in FIG.

  Thereby, since the primary conductor 3 is arrange | positioned along the guide hole 14 of the guide convex part 13, the primary conductor 3 is linked with the core 4. FIG.

  FIG. 6 is a perspective view showing an example of a circuit board to which the current detection device according to Embodiment 1 is attached. As shown in FIG. 6, the circuit board 101 is mounted with a magnetic sensor IC (Integrated Circuit) chip 111 at a predetermined position, and further has a fixing hole 102 at a position corresponding to the fixing protrusion 21. The circuit board 101 also has a hole 103 for inserting the primary conductor 3 and a hole 104 for inserting the terminals 51 and 52.

  In the first embodiment, the current detection device is mounted and fixed to the circuit board 101 by the fixing protrusion 21 and the fixing hole 102. However, instead of the fixing protrusion 21, a hole is formed, and the hole and the fixing hole are fixed. 102 may be connected to each other by another member such as a spacer and fixed to each other.

  The magnetic sensor IC chip 111 is a flux gate type magnetic sensor IC chip that detects magnetic flux for current detection. For example, the magnetic sensor IC chip 111 incorporates a flux gate type magnetic sensor described in Patent Document 2 (US Patent Application Publication No. 2014/0218018).

  For example, the magnetic sensor IC chip 111 is soldered to a wiring pattern (not shown) on the circuit board 101, and is thereby fixed to the circuit board 101. The magnetic sensor IC chip 111 detects a magnetic flux parallel to the mounting surface (that is, parallel to the bottom surface and the top surface of the package of the magnetic sensor IC chip 111).

  When the above-described current detection device is attached to the circuit board 101, the gap 41 between the fixed protrusion 21 of the above-described current detection device and the core 4 is arranged so that the magnetic sensor IC chip 111 is disposed immediately below the gap 41 of the core 4. The magnetic sensor IC chip 111 is fixed at a predetermined position with respect to the fixing hole 102.

  That is, the gap 41 is in contact with the upper surface of the magnetic sensor IC chip 111 in the magnetic path formed by the core 4 or is located above the magnetic sensor IC chip 111 when the current detection device is mounted on the circuit board 101. It is arranged at the place.

  As shown in FIG. 5, the protrusion 42 of the core 4 reduces the distance between the gap 41 and the magnetic sensor IC chip 111 when the current detection device is attached to the circuit board. Can be easily detected by the magnetic sensor IC chip 111.

  Further, in the current detection device, the core 4 is fixed substantially parallel to the bottom surface portion 2a of the lower case member 2, and when the current detection device is attached to the circuit board 101 (that is, the lower case member). 2 is attached to the circuit board 101), the bottom surface 2a and the circuit board 101 are substantially parallel to each other. Therefore, when the current detection device is attached to the circuit board 101 (that is, when the lower case member 2 is attached to the circuit board 101), the core 4 is substantially parallel to the circuit board 101, that is, The two end faces that are arranged horizontally and that constitute the gap 41 of the core 4 are substantially perpendicular to the circuit board 101 and the magnetic sensor IC chip 111.

  Next, the operation of the current detection device according to Embodiment 1 will be described. FIG. 7 is a side view showing the current detection device according to Embodiment 1 in a state of being mounted on the circuit board 101. FIG. 8 is a diagram illustrating a current detection operation of the current detection device according to the first embodiment.

  As shown in FIG. 7, the current detection device according to the first embodiment is mounted on the circuit board 101, and a circuit that outputs a current to be detected is electrically connected to the primary conductor 3. In addition, a current measurement circuit that drives the correction coil 6 according to the magnetic flux detected by the magnetic sensor IC chip 111 is provided on the circuit board 101, and the current measurement circuit is connected to the magnetic sensor IC chip 111 and the terminals 51 and 52. Electrically connected.

  As shown in FIG. 8, at the time of current detection, the current Ip to be detected conducts the primary conductor 3, so that the magnetic flux Tp is induced in the core 4, and the leakage magnetic flux in the vicinity of the gap 41 passes through the magnetic sensor IC chip 111. . In this way, a magnetic flux corresponding to the current Ip to be detected is conducted to the magnetic sensor IC chip 111. The magnetic sensor IC chip 111 generates a compensation current by the leakage magnetic flux, and the correction coil 6 induces the magnetic flux Tc in the core 4 so that the magnetic flux becomes zero based on the compensation current. Then, based on the current value of the correction coil 6 when the magnetic flux detected by the magnetic sensor IC chip 111 becomes zero, the current value of the current Ip to be detected is specified.

  As described above, the current detection device according to the first embodiment can be mounted on the circuit board 101 on which the fluxgate type magnetic sensor IC chip 111 that detects magnetic flux for current detection is mounted, and is detected. A substantially annular core 4 is provided that forms a magnetic path for magnetic flux induced by the current of interest. The core 4 is arranged in a direction substantially parallel to the circuit board 101 when the current detection device is mounted on the substrate 101, and a magnetic path by the core 4 when the current detection device is mounted on the substrate 101. 1 has a gap 41 at a position located above or above the magnetic sensor IC chip 111.

  As a result, the gap 41 is disposed close to the magnetic sensor IC chip 111 mounted on the surface of the circuit board 101 and the core 4 is placed horizontally, so that a low-profile current detection device can be obtained.

Embodiment 2. FIG.

  The current detection device according to the second embodiment of the present invention includes the same components as the current detection device according to the first embodiment. However, in the second embodiment, the upper case member 1 and the lower case member 2 have a magnetic shielding function.

  In the second embodiment, the upper case member 1 and the lower case member 2 are made of a soft magnetic material having a high magnetic permeability such as permalloy. Note that only the upper case member 1 or only the lower case member 2 may be formed of a soft magnetic material.

  However, a part of the side surface of the upper case member 1 and the lower case member 2 is formed of a nonmagnetic material so as not to form a circular magnetic path for the primary conductor 3. Similarly, the upper surface of the upper case member 1 and a part of the bottom surface of the lower case member 2 are formed of a nonmagnetic material so as not to form a circular magnetic path for the primary conductor 3. For example, in the upper case member 1 and the lower case member 2, a predetermined portion that extends substantially perpendicular to the direction of the circulating magnetic flux due to the current Ip to be detected is formed of a nonmagnetic material such as resin.

  As described above, even if the upper case member 1 and the lower case member 2 are formed of a magnetic material, the opening 22 is provided at the arrangement position of the gap 41 of the core 4 in the bottom surface portion 2a of the lower case member 2. The leakage magnetic flux from the gap 41 is conducted to the magnetic sensor IC chip 111.

  As described above, according to the second embodiment, since the upper case member 1 and the lower case member 2 have a magnetic shielding function, the influence of the disturbance magnetic flux induced by the current conducted in the vicinity is small. Become.

Embodiment 3 FIG.

  FIG. 9 is a perspective view showing the core of the current detection device according to Embodiment 3 of the present invention. The current detection device according to the third embodiment includes a core 81 as shown in FIG. 9 instead of the core 4. Since the other configuration of the current detection device according to the third embodiment is the same as that of the first or second embodiment, the description thereof is omitted.

  In the third embodiment, the core 81 is a substantially annular core that forms a magnetic path for the magnetic flux Tp induced by the current Ip to be detected. In this embodiment, the core 81 includes a plurality of core members 81a and 81b which are UU cores. There is a gap 82 between one end surface of the core member 81a and one end surface of the core member 81b, and the other end surface of the core member 81a and the other end surface of the core member 81b are joined to each other.

  In addition, one leg portion of the core members 82a and 82b forming the gap 82 has a protruding portion 83 protruding downward (to the bottom surface side) and a notch portion 84 having substantially the same shape as the protruding portion 83. Further, in the third embodiment, the protruding portion 83 has a cutout portion 85 having a shape that matches the shape of the magnetic sensor IC chip 111. The notch 85 has a shape that covers part or all of the side surface of the magnetic sensor IC chip 111 when the current detection device is mounted on the circuit board 101. For example, the notch 85 has substantially the same height as the height of the magnetic sensor IC chip 111 (that is, the distance from the surface of the circuit board 101 to the upper surface of the package of the magnetic sensor IC chip 111).

  9 covers the upper surface and two side surfaces of the magnetic sensor IC chip 111, but may have a shape covering the upper surface and four side surfaces of the magnetic sensor IC chip 111.

Embodiment 4 FIG.

  FIG. 10 is a side view showing an example of the core of the current detection device according to Embodiment 4 of the present invention. The current detection device according to the fourth embodiment includes a core 91 shown in FIG. Since the other configuration of the current detection device according to the fourth embodiment is the same as that of the first or second embodiment, the description thereof is omitted.

  In the fourth embodiment, the core 91 is a substantially annular core that forms a magnetic path for the magnetic flux Tp induced by the current Ip to be detected. In this embodiment, the core 91 includes a plurality of core members 91a and 91b which are UU cores. There is a gap 92 between one end face of the core member 91a and one end face of the core member 91b, and the other end face of the core member 91a and the other end face of the core member 91b are joined to each other.

  Furthermore, in Embodiment 4, the width of the gap 92 changes along the height direction, and the gap 92 becomes wider toward the bottom surface side of the core 91. The shape of the core 91 other than the gap 92 is the same as that of the core 4.

  In the core 91 shown in FIG. 10, the end surfaces of the core members 91a and 91b constituting the gap 92 are formed in a stepped shape, but may be formed in an inclined slope shape or a curved shape.

Embodiment 5 FIG.

  The current detection device according to the fifth embodiment of the present invention further includes a plate-like magnetic shielding member in any of the first to fourth embodiments.

  FIG. 11 is a perspective view showing a state where the upper case member 1 and the primary conductor 3 are removed from the current detection device according to the fifth embodiment. FIG. 12 is a perspective view showing a state where the upper case member, the lower case member, and the primary conductor are removed from the current detection device according to the fifth embodiment. In addition, since it is the same as that of any one of Embodiment 1-4 about the other structure of the electric current detection apparatus which concerns on Embodiment 5, the description is abbreviate | omitted.

  As shown in FIGS. 11 and 12, the magnetic shielding member 201 is disposed between the core 4 and the case (the lower case member 2, that is, the support member for the core 4). Note that the magnetic shielding member 201 is disposed away from the core 4 so as not to contact the core 4. For example, it is fixed to the core 4 or the lower case member 2 via an adhesive, a nonmagnetic member, or the like.

  As shown in FIG. 12, the magnetic shielding member 201 includes a flat plate-like upper surface portion 201a and two flat plate-like side surface portions 201b facing each other. The side part 201b extends perpendicularly from the upper part 201a. In the fifth embodiment, the magnetic shielding member 201 is composed of one member, but may be composed of a plurality of members (separate members corresponding to the upper surface portion 201a and the side surface portion 201b). The magnetic shielding member 201 is not linked to the primary conductor 3. Further, the upper surface portion 201a of the magnetic shielding member 201 is disposed above the gaps 41, 82, and 92 (that is, the magnetic sensor IC chip 111) of the cores 4, 81, 91, and the side surface portion 201b of the magnetic shielding member 201 is The gaps 41, 82, 92 of the cores 4, 81, 91 (that is, the magnetic sensor IC chip 111) are disposed on the side.

  The magnetic shielding member 201 is made of, for example, a material such as ferrite (Ni—Zn ferrite, Mn—Zn ferrite, Ba ferrite, Ferroc planar ferrite, etc.), amorphous magnetic alloy, silicon steel plate, permalloy, and nanocrystal magnetic alloy. Consists of.

  By providing the magnetic shielding member 201 in this way, the influence of the disturbance magnetic flux induced by the current conducted in the vicinity is reduced.

Embodiment 6 FIG.

  In the electronic device manufacturing method according to Embodiment 6 of the present invention, the first manufacturer manufactures and sells the current detection device according to any of Embodiments 1 to 5 described above, and the second manufacturer The magnetic sensor IC chip 111 is manufactured and sold, and the third manufacturer purchases the current detection device and the magnetic sensor IC chip 111, and the current detection device and the magnetic sensor IC chip are provided on the circuit board 101. 111 and the above-described current measurement circuit are mounted to manufacture an electronic device. At that time, the third manufacturer determines the number of primary conductors 3 connected in series with each other, the measurement range of the above-described current measurement circuit, and the like according to the current value range of the current to be detected in the electronic device. After that, the above-described current detection device and current measurement circuit are mounted.

  Since the current detection device is configured as described above, the circuit board 101 of the electronic device manufactured by the third manufacturer is described above in accordance with the positional relationship between the fixing protrusion 21 and the gap 41 of the current detection device. And mounting the magnetic sensor IC chip 111 and mounting the current detection device on the circuit board 101, the third manufacturer can adjust the current detection device according to the specifications of the electronic device. Can be easily installed in the electronic device.

  Various changes and modifications to the above-described embodiment will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. That is, such changes and modifications are intended to be included within the scope of the claims.

  For example, in the first to fifth embodiments, the end surfaces that are joined to each other, which are different from the end surfaces that form the gaps 41, 82, and 92 in the core members 4a, 4b, 81a, 81b, 91a, and 91b, are shown in FIG. In addition to the end face substantially perpendicular to the magnetic path as shown, it may be an inclined face or a step face. Moreover, you may make it join the end surface mutually with a magnetic adhesive agent.

  In the first to fifth embodiments, the gaps 41, 82, and 92 may be provided with nonmagnetic spacers, or may be filled with nonmagnetic adhesives or fillers. Further, on the upper surface side of the cores 4, 81, 91, a part of the gaps 41, 82, 92 (a space between a part of one end face constituting the gap 41, 82, 92 and a part of the other end face) ) May be filled with a soft magnetic adhesive or filler.

  In the first to fifth embodiments, in order to reduce the influence of disturbance, a magnetic sheet of soft magnetic material is disposed between the circuit board 101 and the magnetic sensor IC chip 111 or the back surface of the circuit board 101. A magnetic sheet made of a soft magnetic material may be attached to (the surface opposite to the mounting surface of the magnetic sensor IC chip 111). As the circuit board 101, a circuit board having a magnetic layer of a soft magnetic material may be used.

  Moreover, in the said Embodiment 1-5, although the cores 4, 81, 91 are comprised by two symmetrical core members 4a, 4b, 81a, 81b, 91a, 91b, they are asymmetrical core members. It may be configured. In the first to third embodiments, the cores 4, 81, 91 may be configured by one core member having a gap. In addition, since the cores 4, 81, 91 are composed of two symmetrical core members 4a, 4b, 81a, 81b, 91a, 91b, the gaps 41, 82, 92 are arranged in the center. In the case of using a plurality of asymmetric core members, the gaps 41, 82, and 92 may not be arranged at the center.

  In the first to fifth embodiments, the current value is detected by the magnetic balance type, but the current value may be detected by the magnetic proportional type. In that case, the bobbin 5 and the correction coil 6 may not be provided.

  The present invention is applicable to, for example, a current sensor.

2 Lower case member (an example of a support member)
3 Primary conductor 4, 81, 91 Core 6 Correction coil 41, 82, 92 Gap 201 Magnetic shielding member

Claims (7)

A current detection device that can be mounted on a substrate on which a fluxgate type magnetic sensor IC chip that detects magnetic flux for current detection is mounted,
A substantially annular core forming a magnetic path for a magnetic flux induced by a current to be detected;
The core is disposed in a direction substantially parallel to the substrate when the current detection device is mounted on the substrate, and the magnetic sensor IC is disposed in the magnetic path when the current detection device is mounted on the substrate. Having a gap at a location located above or above the chip;
A current detection device characterized by the above. A support member attachable to the substrate;
The core is directly or indirectly fixed to the support member;
The gap is located at a position above or above the magnetic sensor IC chip when the support member is attached to the substrate;
The current detection device according to claim 1.   The current detection device according to claim 1, wherein two end faces constituting the gap in the core are substantially perpendicular to the substrate. A primary conductor that is arranged to be linked to the core and conducts a current to be detected;
A correction coil for inducing a magnetic flux in the core for canceling out the magnetic flux induced in the core by the current of the primary conductor;
The current is detected in a magnetic equilibrium manner;
The current detection device according to claim 1, wherein: The support member is a part or all of a case that houses the core,
The case has a magnetic shielding function,
The case includes an opening at a position where the gap of the core is disposed on a bottom surface of the case;
The current detection device according to claim 1, wherein: It further comprises a plate-like magnetic shielding member,
The support member is a part or all of a case that houses the core,
The magnetic shielding member is disposed between the core and the case;
The current detection device according to claim 1, wherein:   The current detection device according to claim 1, wherein the core is a ferrite core.

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