JP6531951B2 - Current detection device - Google Patents

Description

  The present invention relates to a current detection device.

  One magnetic balance type current sensor has a vertical (that is, vertical) annular core, a primary conductor is disposed to interlink with the annular core, and a correction coil (secondary coil) is provided on the annular core Furthermore, a cavity is provided at the bottom of the annular core, and a rod-shaped fluxgate sensor core is inserted in the cavity, and a control substrate for driving the sensor core is a substrate 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, in addition to the rod-like sensor for special applications as described above, there is a sensor in the form of an IC chip which incorporates a circuit configuration as described in Patent Document 2, for example.

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

  However, the above-mentioned current sensor is tall because it uses a vertical annular core, and when the current sensor is installed on a substrate, the height of the current sensor is adjusted above the substrate. Space is required.

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

The current detection device according to the present invention is a current detection device mountable on a substrate on which a flux gate type magnetic sensor IC chip for detecting a 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 magnetic flux, and a case that accommodates the core . The core is disposed in a direction substantially parallel to the substrate when the current detection device is mounted on the substrate, and the core is mounted on the magnetic sensor IC chip in the magnetic path when the current detection device is mounted on the substrate. Or it has a gap in the point located in the upper part. Furthermore, the case is provided with an opening at the bottom of the case at the position of the gap of the core, and the core has a projection which projects into the opening of the case in the leg forming the gap.

  According to the present invention, a low-profile current detection device 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 a bottom surface of the current detection device according to Embodiment 1 of the present invention. FIG. 3 is a perspective view showing the inner surface of the upper case member in FIG. FIG. 4 is a perspective view of the current detection device shown in FIG. 1 with the upper case member and the primary conductor removed. 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 the first embodiment is attached. FIG. 7 is a side view showing the current detection device according to the first embodiment in a state of being mounted on the circuit board 101. FIG. 8 is a diagram for explaining the current detection operation of the current detection device according to the first embodiment. FIG. 9 is a perspective view showing a core of a 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 in which the upper case member and the primary conductor are removed in the current detection device according to the fifth embodiment. FIG. 12 is a perspective view showing a state in which the upper case member, the lower case member, and the primary conductor of the current detection device according to the fifth embodiment are removed.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

Embodiment 1

  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 a bottom surface of the current detection device according to Embodiment 1 of the present invention. FIG. 3 is a perspective view showing the inner surface of the upper case member in FIG. FIG. 4 is a perspective view of the current detection device shown in FIG. 1 with the upper case member and the primary conductor removed.

  The current detection device according to the first embodiment is a current detection device that can be mounted on a substrate on which a flux gate type magnetic sensor IC chip that detects a 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 to 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 the claws 12 at the ends of opposing two side surfaces of the upper case member 1 being fitted into the lower case member 2.

  The primary conductor 3 is a metal member which conducts the current Ip to be detected. In FIG. 1, the number of primary conductors 3 is four, but may be one, or the number may be as required. Also, the primary conductor 3 may be a bus bar.

  As shown in FIG. 3, the upper case member 1 has a guide convex portion 13 which stands upright from the top surface thereof, and the guide convex portion 13 has the same number of guide holes 14 as the grooves 11. The guide hole 14 is formed 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 on which the correction coil 6 is mounted by the bobbin 5 is fixed to the inside of the lower case member 2. The correction coil 6 is wound around a bobbin 5. The lower case member 2 has a substantially square flat bottom portion 2a, and four substantially flat side portions 2b extending upright from the bottom portion 2a. The core 4 to which the bobbin 5 and the correction coil 6 are attached is fitted between the side surface portions 2 b, disposed substantially parallel to the bottom surface portion 2 a of the lower case member 2, and fixed to the lower case member 2.

  Although the core 4 is directly fixed to the lower case member 2 in the first embodiment, another mounting member may be used to indirectly fix the core 4 to the lower case member 2. 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, in turn, are substantially perpendicular to the bottom surface 2 a of the lower case member 2.

  Further, one leg of the core members 4a and 4b forming the gap 41 has a projecting portion 42 projecting downward (to the bottom surface side), and has a cutout 43 having substantially the same shape as the projecting portion 42.

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

  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 with a ferrite material. As the ferrite material, an Mn-Zn based ferrite material, an Ni-Zn based ferrite material or the like can be used, and in terms of permeability, the Mn-Zn based ferrite material is preferable. The magnetic material of the core 4 is not limited to the ferrite material.

  For example, when a complex core shape is required as in the core described in Patent Document 1 (Japanese Patent Application Publication No. 2011-510318), use of a material with good workability but expensive such as permalloy or amorphous alloy is required. Be done. On the other hand, in this embodiment, by using the core 4 as a ferrite core, the current detection device can be manufactured inexpensively. In the case of a ferrite core, the magnetic flux density is nonlinear with respect to the strength of the magnetic field (that is, the current to be detected), but by detecting the current by the magnetic balance method, The magnetic flux density decreases and does not cause any problem.

  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 bobbin made of resin, and includes terminals 51, 52, 53, 54 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 4a and 4b is inserted into the opening 55, and the correction coil 6 is attached to the core 4.

  In order to detect the current in a magnetic balance manner, the correction coil 6 induces a magnetic flux Tc in the core 4 to cancel 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 the current input using the terminals 51-54.

  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 supports the core 4 and functions as a support member attachable to the circuit board. Furthermore, the lower case member 2 has an opening 22 below the arrangement position of the gap 41 of the core 4. Thus, the periphery of the gap 41 of the core 4 is exposed by the opening 22. Further, as shown in FIG. 4, the lower case member 2 has a guide cylinder 23 which stands upright from the inner bottom surface thereof. The hollow portion of the guide cylinder 23 penetrates the bottom 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 is a guide cylinder 23. The distal end of the guide projection 13 is exposed as shown in FIG.

  As a result, the primary conductor 3 is disposed along the guide hole 14 of the guide convex portion 13, so the primary conductor 3 interlinks with the core 4.

  FIG. 6 is a perspective view showing an example of a circuit board to which the current detection device according to the first embodiment is attached. As shown in FIG. 6, the circuit board 101 has a magnetic sensor IC (Integrated Circuit) chip 111 mounted 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, but a hole is formed instead of the fixing protrusion 21, and the hole and the fixing hole It may be connected with another member 102 such as a spacer or the like and fixed to each other.

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

  The magnetic sensor IC chip 111 is soldered to, for example, 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 magnetic flux parallel to the mounting surface (that is, parallel to the bottom and top 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 current detection device and the core 4 is arranged such that the magnetic sensor IC chip 111 is disposed directly 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 in accordance with the positional relationship with the above.

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

  Further, as shown in FIG. 5, the protruding portion 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, and the leakage flux due to the gap 41 The magnetic sensor IC chip 111 can be easily detected.

  Furthermore, in the current detection device, the core 4 is fixed substantially parallel to the bottom surface 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 part 2a and the circuit board 101 become substantially parallel. 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 disposed laterally and constituting 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 the first embodiment will be described. FIG. 7 is a side view showing the current detection device according to the first embodiment in a state of being mounted on the circuit board 101. FIG. 8 is a diagram for explaining the 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. Further, a current measurement circuit for driving the correction coil 6 in accordance with the magnetic flux detected by the magnetic sensor IC chip 111 is provided on the circuit board 101, and the current measurement circuit is provided on 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 to induce the magnetic flux Tp in the core 4, and the leakage flux in the vicinity of the gap 41 passes through the magnetic sensor IC chip 111. . In this manner, the magnetic flux corresponding to the current Ip to be detected is conducted to the magnetic sensor IC chip 111. Then, the magnetic sensor IC chip 111 generates a compensation current by the leakage flux, and the correction coil 6 induces a magnetic flux Tc in the core 4 so that the flux becomes zero based on the compensation current. Then, the current value of the current Ip to be detected is identified based on the current value of the correction coil 6 when the magnetic flux detected by the magnetic sensor IC chip 111 becomes zero.

  As described above, the current detection device according to the first embodiment is attachable to the circuit board 101 on which the fluxgate type magnetic sensor IC chip 111 for detecting the magnetic flux for current detection is mounted, It comprises a substantially annular core 4 forming a magnetic path for the magnetic flux induced by the current of interest. The core 4 is disposed in a direction substantially parallel to the circuit board 101 when the current detection device is mounted on the substrate 101, and the magnetic path by the core 4 when the current detection device is mounted on the substrate 101 The magnetic sensor IC chip 111 has a gap 41 at a position located on or above the magnetic sensor IC chip 111.

  As a result, the gap 41 is disposed in proximity 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.

Second Embodiment

  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 formed of a high magnetic permeability soft magnetic material such as permalloy. Note that only the upper case member 1 or 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 an orbiting magnetic path with respect to 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 an orbiting magnetic path with respect to the primary conductor 3. For example, in the upper case member 1 and the lower case member 2, predetermined portions extending substantially perpendicularly to the direction of the circulating magnetic flux due to the current Ip to be detected are formed of a nonmagnetic material such as resin.

  Thus, 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 at the bottom surface 2a of the lower case member 2 The leakage 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 the magnetic shielding function, the influence of the disturbance magnetic flux induced by the current conducted in the vicinity is small. Become.

Third Embodiment

  FIG. 9 is a perspective view showing a core of a 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. The other configuration of the current detection device according to the third embodiment is the same as that of the first embodiment or the second embodiment, and thus 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 face of the core member 81a and one end face of the core member 81b, and the other end face of the core member 81a and the other end face of the core member 81b are joined to each other.

  Further, one leg of each of the core members 82a and 82b forming the gap 82 has a projecting portion 83 projecting downward (to the bottom surface side) and a cutout 84 having substantially the same shape as the projecting portion 83. Furthermore, in the third embodiment, the projecting portion 83 has the cutout portion 85 shaped to match the shape of the magnetic sensor IC chip 111. The cutout portion 85 is shaped so as to cover 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 a height substantially the same as the height of the magnetic sensor IC chip 111 (that is, the distance from the surface of the circuit board 101 to the top surface of the package of the magnetic sensor IC chip 111).

  Although the core 81 shown in FIG. 9 covers the upper surface and the two side surfaces of the magnetic sensor IC chip 111, the core 81 may cover the upper surface and the four side surfaces of the magnetic sensor IC chip 111.

Fourth Embodiment

  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. 10 instead of the core 4. The other configuration of the current detection device according to the fourth embodiment is the same as that of the first embodiment or the second embodiment, and thus 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 the fourth embodiment, the width of the gap 92 changes along the height direction, and the gap 92 is wider toward the bottom 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 faces of the core members 91a and 91b constituting the gap 92 are formed in a step shape, but may be inclined sloped or curved.

Embodiment 5

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

  FIG. 11 is a perspective view showing a state in which upper case member 1 and primary conductor 3 of the current detection device according to the fifth embodiment are removed. FIG. 12 is a perspective view showing a state in which the upper case member, the lower case member, and the primary conductor of the current detection device according to the fifth embodiment are removed. The other configuration of the current detection device according to the fifth embodiment is the same as that of any of the first to fourth embodiments, and thus the description thereof will be 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, a supporting member of the core 4). The magnetic shielding member 201 is disposed apart 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 upper surface portion 201 a and two opposing flat surface portions 201 b. The side surface portion 201 b extends vertically from the upper surface portion 201 a. In the fifth embodiment, the magnetic shielding member 201 is formed of one member, but may be formed 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, 92 of the cores 4, 81, 91 (that is, the magnetic sensor IC chip 111), and the side surface portion 201b of the magnetic shielding member 201 is It is disposed on the side of the gaps 41, 82, 92 of the cores 4, 81, 91 (that is, the magnetic sensor IC chip 111).

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

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

Sixth Embodiment

  In the method of manufacturing an electronic device according to the sixth embodiment of the present invention, the first manufacturer manufactures and sells the current detection device of any of the first to fifth embodiments described above, and the second manufacturer , Manufacture and sell the above-mentioned magnetic sensor IC chip 111, and the third manufacturer purchases the current detection device and the magnetic sensor IC chip 111, and on the circuit board 101, the current detection device, the magnetic sensor IC chip 111 and the above-mentioned current measurement circuit are mounted to manufacture an electronic device. At this time, the third manufacturer determines the number of primary conductors 3 connected in series with each other, the measurement range of the above-mentioned current measurement circuit, and the like according to the range of the current value of the current to be detected in the electronic device. Then, the above-mentioned current detection device and current measurement circuit are implemented.

  Since the current detection device is configured as described above, the circuit board 101 of the electronic device manufactured by the third manufacturer is matched to the positional relationship between the fixing projection 21 and the gap 41 of the current detection device. The third manufacturer mounts the current detection device on the circuit board 101 by mounting the magnetic sensor IC chip 111 and forming the fixed hole 103 of the third current detector according to the specifications of the electronic device. Can be easily installed in the electronic device.

  Note that 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 the intended advantages. That is, such changes and modifications are intended to be included in the scope of the claims.

  For example, in the first to fifth embodiments, in the core members 4a, 4b, 81a, 81b, 91a, 91b, the end faces joined to each other, which are different from the end faces forming the gaps 41, 82, 92, are shown in FIG. Other than the end face substantially perpendicular to the magnetic path as shown, it may be an inclined surface or a stepped surface. Further, the end faces may be bonded to each other by a magnetic adhesive.

  In the first to fifth embodiments, nonmagnetic spacers may be disposed in the gaps 41, 82 and 92, or nonmagnetic adhesives and fillers may be filled. 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 gaps 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, a magnetic sheet of soft magnetic material may be disposed between the circuit board 101 and the magnetic sensor IC chip 111 or the back surface of the circuit board 101 in order to reduce the influence of disturbance. A magnetic sheet of a soft magnetic material may be attached to (the surface opposite to the mounting surface of the magnetic sensor IC chip 111). Further, 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 core members 4a, 4b, 81a, 81b, 91a, 91b symmetrical, they are asymmetrical several core member. 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. Incidentally, 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 disposed at the center, When using a plurality of asymmetric core members, the gaps 41, 82, 92 need not be centrally located.

  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, the correction coil 6, etc. may not be provided.

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

2 Lower case member (example of 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 mountable on a substrate on which a fluxgate magnetic sensor IC chip for detecting a magnetic flux for current detection is mounted,
A substantially annular core forming a magnetic path for the magnetic flux induced by the current to be detected ;
And a case for housing the core ,
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 in the magnetic path when the current detection device is mounted on the substrate have a gap at a position located on or above the chip,
The case is provided with an opening at an arrangement position of the gap of the core on a bottom surface of the case,
The core has, in a leg forming the gap, a protrusion which protrudes into the opening;
A current detection device characterized by The apparatus further comprises a support member attachable to the substrate,
The core is fixed directly or indirectly to the support member,
The gap is located on or above the magnetic sensor IC chip when the support member is attached to the substrate.
The current detection device according to claim 1, characterized in that   The current detection device according to claim 1 or 2, wherein two end faces forming the gap in the core are substantially perpendicular to the substrate. A primary conductor disposed so as to interlink with the core and conducting a current to be detected;
And a correction coil for inducing a magnetic flux in the core to cancel the magnetic flux induced in the core by the current of the primary conductor.
The current is detected in a magnetic balance manner.
The current detection device according to any one of claims 1 to 3, characterized in that The support member is a part or the whole of the pre-listen over scan,
The case is to have a magnetic shielding function,
The current detection device according to claim 2 , characterized in that It further comprises a plate-like magnetic shielding member,
The support member is a part or the whole of the pre-listen over scan,
The magnetic shielding member is disposed between the core and the case;
The current detection device according to claim 2 , characterized in that   The current detection device according to any one of claims 1 to 6, wherein the core is a ferrite core.

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