JP2016173379A - Current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor which has high sensitivity, is hardly saturated, and has a wide dynamic range.SOLUTION: In a current sensor, a first current path, a second current path extending from one end of the first current path, and a third current path extending from the other end of the first current path are included. The second current path and the third current path are provided on the same side, to a plane in which the first current path is included. In the current sensor, a first magnetic field control plate, a second magnetic field control plate extending from one end of the first magnetic field control plate, and a third magnetic field control plate extending from the other end of the first magnetic field control plate are included. The second magnetic field control plate and the third magnetic field control plate are provided on the same side, to a plane in which the first magnetic field control plate is included. A magnetic sensor element is positioned on the other side to the first magnetic field control plate with respect to the first current path, and opposingly to the first current path. A direction in which the second current path and the third current path are provided to the first current path, and a direction in which the second magnetic field control plate and the third magnetic field control plate are provided to the first magnetic field control plate are same.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a current sensor that calculates a current value based on a magnetic field generated by a current to be measured, and more particularly to a current sensor that can be miniaturized.

  In recent years, a current sensor that is attached to a device and measures a current flowing through the device is generally used for controlling and monitoring various devices. As this type of current sensor, a current sensor using a magnetic sensor element such as a magnetoresistive effect element or a Hall element that senses a magnetic field generated from a current flowing in a current path is known.

  As an example of such a current sensor, Patent Document 1 discloses a current sensor in which a current line through which a current to be measured flows has a U shape. The structure of the current sensor 900 disclosed in Patent Document 1 is shown in FIG.

  In the current sensor 900, parallel current line portions 932a and 932b having the same amount of current flowing in opposite directions are arranged on the circuit board 930 through the through holes 930a, and the axes of the parallel current line portions 932a and 932b are arranged. The magnetic detection element 910 is disposed on an extension line connecting the two. The magnetic field detection direction of the magnetic detection element 910 is a direction perpendicular to the extension line, and the magnetic field of the parallel current line portion 932b near the magnetic detection element 910 is opposite to the parallel current line portion 932a on the far side. The amount of current flowing in the parallel current line portion 932 is detected by detecting the difference in magnetic field.

  According to this configuration, it is possible to provide the current sensor 900 that can detect the amount of current with high sensitivity and can be easily produced without increasing the size of the current sensor 900.

JP 2004-317166 A JP 2012-242176 A

  However, the current sensor 900 disclosed in Patent Document 1 has the following problems.

  In the current sensor 900, a plurality of terminals are attached to the circuit board 930 in order to transmit information on the measured current amount to an external circuit. The plurality of terminals are attached to the end portion of the circuit board 930. In order to maintain insulation resistance between the parallel current line portion 932a on the side close to the terminal and the terminal, the amount of current to be measured is large. It is necessary to secure an insulation distance corresponding to the thickness. Therefore, when the amount of current to be measured increases, it is necessary to increase the distance between the parallel current line portion 932a and the plurality of terminals. As a result, there is a problem that it is difficult to reduce the size of the current sensor 900. In addition, there is no core or magnetic field control plate for collecting magnetic flux, and it is difficult to increase sensitivity, and there is a problem that a small current cannot be measured. On the other hand, in a general current sensor using a core, there is no structure that suppresses saturation of the core, and there is a problem that a large current cannot be measured.

  The present invention has been made in view of such a state of the art, and an object thereof is to provide a current sensor capable of extending a measurement range (dynamic range).

  The current sensor of the present invention includes a current path through which a current to be measured flows, a magnetic field control plate that controls a magnetic field generated by the current to be measured, and a magnetic sensor element that measures the magnetic field, and the current path includes: A first current path, a second current path extending from one end of the first current path with an inclination to the first current path, and an inclination from the other end of the first current path A third current path extending, and the second current path and the third current path are provided on the same side with respect to a plane including the first current path, and the magnetic field The control plate includes a first magnetic field control plate, a second magnetic field control plate extending from one end of the first magnetic field control plate with an inclination with respect to the first magnetic field control plate, and the first magnetic field control. A third magnetic field control plate extending with an inclination from the other end of the plate, and the second magnetic field control plate, The magnetic field control plate is provided on the same side with respect to the plane including the first magnetic field control plate, and the magnetic sensor element is the first magnetic field control plate with respect to the first current path. Opposite to the first current path, the first current path and the first magnetic field control plate are parallel to each other, and the first current path is parallel to the first current path. The direction in which the second current path and the third current path are provided is the same as the direction in which the second magnetic field control plate and the third magnetic field control plate are provided with respect to the first magnetic field control plate. It is characterized by being.

According to this configuration, the induced magnetic field (magnetic flux) generated in the second current path and the third current path flows in a direction penetrating the second magnetic field control plate and the third magnetic field control plate. , Merged with the induced magnetic field generated in the first current path. The induced magnetic field generated in the second current path and the third current path is generated so as to surround the second current path or the third current path, and therefore does not pass through the first magnetic field control plate.
Therefore, even when a large current flows through the current path, the first magnetic field control plate is hardly saturated and high sensitivity can be obtained.
That is, according to this configuration, the induced magnetic field that passes through the first magnetic field control plate, which is the central region of the magnetic field control plate, is only the induced magnetic field generated from the first current path. That is, since the induced magnetic field generated from the second current path and the third current path does not pass through the first magnetic field control plate, the first magnetic field control plate is less likely to be saturated, and a large current is generated. Measurement can be made accurately. Further, since the magnetic flux passing through the magnetic sensor is increased, the sensitivity is increased and a small current can be accurately measured. Therefore, the measurement range (dynamic range) can be expanded.

  The first current path, the second current path, and the third current path are at right angles, and the first magnetic field control plate, the second magnetic field control plate, and the third magnetic field control plate, Has a feature of being a right angle.

  According to this configuration, the shielding function of the external magnetic field of the magnetic field control plate can be enhanced.

  According to the present invention, both a large current and a small current can be measured accurately, and the measurement range (dynamic range) can be expanded.

It is a perspective view which shows the external appearance of the current sensor which concerns on embodiment of this invention of the state which removed the housing | casing. It is a perspective view which shows the external appearance of a current sensor. It is a side view of a current sensor. It is a side view of a current sensor. It is a top view of a current sensor. It is a schematic diagram which shows the distance between each component requirements of a current sensor. It is a schematic diagram which shows the distance between each component requirements of a current sensor. It is a perspective view which shows the external appearance of the modification of the current sensor of the state which removed the housing | casing. It is a top view of the modification of a current sensor. It is a schematic diagram which shows the distance between each component of the modification of a current sensor. It is an external view of the current sensor concerning the 2nd modification of embodiment of this invention. It is a figure for demonstrating the magnetic field which arises in the current sensor shown in FIG. It is a perspective view which shows the external appearance of the current sensor which concerns on a prior art example. It is an external view of the current sensor concerning the comparative example of the embodiment of the present invention. It is a figure for demonstrating the induction magnetic field which arises in the current sensor shown in FIG.

[Comparative example]
Hereinafter, a comparative example of the embodiment of the present invention will be described.
FIG. 14 is an external view of a current sensor 800 according to a comparative example of the embodiment of the present invention. FIG. 15 is a diagram for explaining an induced magnetic field generated in current sensor 800 shown in FIG.

  The current sensor 800 of the comparative example includes a current path 801 through which a current to be measured flows, a magnetic field control plate 803 that controls a magnetic field (inductive magnetic field) generated by the current to be measured through the current path 801, and a magnetic sensor element that measures the magnetic field. 807.

The current path 801 includes a first current path 821, a second current path 822 extending in the Z2 direction from one end of the first current path 821, and a third current path 801 extending in the Z2 direction from the other end of the first current path 821. Current path 823.
The current path 801 has a U shape, and the first current path 821, the second current path 822, and the third current path 823 are substantially perpendicular to each other.

The magnetic field control plate 803 includes a first magnetic field control plate 831, a second magnetic field control plate 832 extending in the Z1 direction from one end of the first magnetic field control plate 831, and Z1 from the other end of the first magnetic field control plate 831. And a third magnetic field control plate 833 extending in the direction.
The magnetic field control plate 803 has a U shape, and the first magnetic field control plate 831, the second magnetic field control plate 832, and the third magnetic field control plate 833 are substantially perpendicular to each other.
The first magnetic field control plate 831 is parallel to the first current path 821.

  In the current sensor 800, the second current path 822 and the third current path 823 extend from the first magnetic field control plate 831 to the second current path 822 in the Z1 direction opposite to the Z2 direction. The magnetic field control plate 832 and the third magnetic field control plate 833 extend.

  The magnetic sensor element 807 is positioned opposite to the first current path 821 on the side opposite to the first magnetic field control plate 831 (Z1 side) with respect to the first current path 821.

  As shown in FIG. 14, in the current sensor 800, the current path 801 and the magnetic field control plate 803 are both U-shaped, and are arranged so that the end portions thereof are opposite to each other. The first current path 821 at the center of the current path 801 is flat and parallel to and faces the flat first magnetic field control plate 831 at the center of the magnetic field control plate 803.

  In the current sensor 800, most of the induced magnetic field generated from the current flowing through the first current path 821 flows through the first magnetic field control plate 831. On the other hand, the Z1 side with respect to the first current path 821 has a structure in which the magnetic field control plate 803 is opened, so that the second magnetic field that is both arms extending perpendicular to the first current path 821. An induced magnetic field passes between the control plate 832 and the third magnetic field control plate 833, and the induced magnetic field is detected by the magnetic sensor element 807.

  As shown in FIG. 15, in the current sensor 800 of the comparative example, the magnetic flux 851 generated by the current flowing through the first current path 821 in the center passes through the magnetic sensor element 807 in the X1 direction, so the accuracy is high. Current can be detected.

On the other hand, the magnetic flux 852 generated by the current flowing through the second current path 822 and the third current path 823 passes through the first magnetic field control plate 831 in the X2 direction. That is, the magnetic flux 852 is sucked by the first magnetic field control plate 831.
Thus, since the magnetic flux 851 and the magnetic flux 852 are the same, when a large current flows through the current path 801, a large amount of magnetic flux passes through the first magnetic field control plate 831 and the first magnetic field control plate 831 is saturated. To do. For this reason, the magnetic shield function of the magnetic field control plate 803 is lowered, and the current in the current path 801 cannot be measured accurately due to the influence of the external magnetic field.

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification, unless otherwise specified, the X1 side of each drawing is described as the right side, the X2 side as the left side, the Y1 side as the back side, the Y2 side as the near side, the Z1 side as the upper side, and the Z2 side as the lower side. To do.

  The configuration and operation of the current sensor 100 according to the embodiment will be described with reference to FIGS. The current sensor 100 is a current sensor that is mounted on various devices and measures a current flowing through the device for control and monitoring. The current sensor 100 is attached on a mother board 51 provided in a device on which the current sensor 100 is mounted.

  FIG. 1 is a perspective view showing the external appearance of the current sensor 100 with the housing 11 removed, and FIG. 2 is a perspective view showing the external appearance of the current sensor 100 with the housing 11 attached. 3 is a side view when the current sensor 100 is viewed from the right side, and FIG. 4 is a side view when the current sensor 100 is viewed from the front side. FIG. 5 is a plan view of the current sensor 100. FIG. 6 is a schematic diagram showing distances in the left-right direction between the constituent elements of the current sensor 100 in a state where the current sensor 100 is mounted on the mother board 51. 1 and 3 to 6 show the current sensor 100 with the housing 11 removed for easy understanding. In FIG. 6, the current path 1 is indicated by a broken line for easy understanding.

  As shown in FIG. 1, a current sensor 100 includes a current path 1 through which a current to be measured flows, a magnetic field control plate 3 that controls a magnetic field generated by the current to be measured, an insulating substrate 5 having a rectangular shape, and an insulating substrate 5. And a sensor IC 7 having a built-in magnetic sensor element 7a for measuring a magnetic field. The insulating substrate 5 is provided with a plurality of terminals 9 electrically connected to the magnetic sensor element 7a. The plurality of terminals 9 are arranged along the first short side 5 a which is one short side of the insulating substrate 5, and are attached to the insulating substrate 5 via the pedestal 13. Further, the tips of both end portions 1a of the current path 1 are divided into a plurality of insertion pieces 1d.

  As shown in FIG. 2, the current sensor 100 includes a resin casing 11, and the main part of the current sensor 100 including the current path 1, the magnetic field control plate 3, and the insulating substrate 5 is inside the casing 11. And is attached with an adhesive or the like. Further, the surface of both end portions 1 a of the current path 1, the surface of the top surface portion 3 c of the magnetic field control plate 3, and the surface of the first short side 5 a of the insulating substrate 5 are in the vicinity of the inner surface of the maximum outer shape of the housing 11. is there. Further, the surfaces of both end portions 1a of the current path 1, the surface of the top surface portion 3c of the magnetic field control plate 3, and the surface of the first short side 5a of the insulating substrate 5 are exposed to the outside.

  Therefore, the main part of the current sensor 100 including the current path 1, the magnetic field control plate 3, and the insulating substrate 5 is within the maximum outline of the housing 11 except for the insertion piece 1 d and the terminal 9. Moreover, the surface of the partial area | region of each of the electric current path 1, the magnetic field control board 3, and the insulated substrate 5 is exposed with respect to the exterior. Therefore, the outer shape of the main part of the current sensor 100 excluding the insertion piece 1d and the terminal 9 is substantially the same as the maximum outer shape of the housing 11. As a result, the casing 11 does not include an extra area, and thus the current sensor 100 can be further downsized.

  As shown in FIG. 3, the current path 1 is bent in a U shape, and is arranged so that both end portions 1 a of the current path 1 abut on both opposing long sides 5 c of the insulating substrate 5. Yes. As shown in FIG. 4, one side surface of each end 1a of the current path 1 is disposed so as to be positioned in the vicinity of the second short side 5b facing the first short side 5a of the insulating substrate 5. Yes. Further, as shown in FIG. 5, the current path 1 is formed to be curved so as to protrude from the right side (X1) to the left side (X2) in plan view.

  As described above, the tips of both ends 1a of the current path 1 are divided into a plurality of insertion pieces 1d. Each insertion piece 1d shown in FIG. 4 is inserted into an attachment hole (not shown) provided in the mother board 51 and attached to the mother board 51 by soldering. As described above, since the tips of both end portions 1a of the current path 1 are divided into the plurality of insertion pieces 1d, when soldering the current sensor 100 to the mother board 51, the heat of the solder is transmitted to the insertion piece 1d. It is easy to make it difficult for the heat of the solder to escape to the end portion 1a.

  As shown in FIGS. 3 and 4, the plurality of terminals 9 are inserted into mounting holes (not shown) provided in a mother board 51 on which an electronic circuit (not shown) is mounted. At the same time, it is attached by solder. As a result, the magnetic sensor element 7 a is connected to an electronic circuit mounted on the mother substrate 51 through the plurality of terminals 9.

  As shown in FIG. 4, the magnetic field control plate 3 is bent in a U shape, and the first end 3 a, which is one end of the magnetic field control plate 3, contacts the second short side 5 b of the insulating substrate 5. It is arranged to touch. On the other hand, the second end 3b which is the other end of the magnetic field control plate 3 is inserted into a mounting hole 5d provided in the insulating substrate 5, as shown in FIGS. By inserting the second end 3 b into the mounting hole 5 d of the insulating substrate 5, the position of the magnetic field control plate 3 with respect to the insulating substrate 5 is determined. Although the magnetic field control plate 3 is attached to the insulating substrate 5, it is not attached to the mother substrate 51 as shown in FIG.

  Further, as shown in FIG. 5, the magnetic field control plate 3 is attached so as to be orthogonal to the current path 1 in plan view. Therefore, when the current path 1 and the magnetic field control plate 3 are orthogonal to each other, an orthogonal portion 1 c having a rectangular shape in plan view is formed in the current path 1. And the center 1e of this orthogonal part 1c is arrange | positioned in the position facing the magnetic sensor element 7a.

  The magnetic field control plate 3 is made of a magnetic material having a high magnetic permeability and a high saturation magnetic flux density, and covers the orthogonal portion 1c of the current path 1 and the magnetic sensor element 7a from above as shown in FIGS. Yes. The magnetic field control plate 3 functions to concentrate the magnetic field generated by the current path 1 around the magnetic sensor element 7a, and also serves to shield the magnetic sensor element 7a by weakening the external magnetic field.

  The position of the magnetic sensor element 7a built in the sensor IC 7 in the direction from the near side to the far side (Y1-Y2 direction) is from the near side to the far side of the magnetic field control plate 3, as shown in FIG. The center position of the opening length D1 in the direction, that is, the position facing the center 1e of the orthogonal portion 1c in plan view. On the other hand, the position of the magnetic sensor element 7a in the left-right direction (X1-X2 direction) is the center position of the opening width D2 in the left-right direction of the magnetic field control plate 3, that is, the width direction of the magnetic field control plate 3, as shown in FIG. The center is set to 3d. In other words, the sensor IC 7 including the magnetic sensor element 7 a is placed so that the position of the magnetic sensor element 7 a is the center position of the rectangular opening of the magnetic field control plate 3. As a result, the center line C1 indicating the mounting position of the magnetic sensor element 7a in the left-right direction is a position that divides the opening width D2 of the magnetic field control plate 3 in the left-right direction into two.

  The magnetic sensor element 7a senses the magnetic field generated from the current to be measured flowing in the current path 1, and determines the value of the current to be measured flowing in the current path 1 based on the value of the magnetic field strength. The value of the current to be measured is transmitted to an electronic circuit (not shown) mounted on the mother board 51 through a plurality of terminals 9 and used for various controls.

  As shown in FIGS. 5 and 6, the width D4 of the orthogonal portion 1c formed in the current path 1 due to the current path 1 and the magnetic field control plate 3 being orthogonal to each other is equal to that of both ends 1a of the current path 1. The width is substantially the same as the width D3.

  As shown in FIG. 6, the width D4 of the orthogonal part 1c of the current path 1 is narrower than the opening width D2 in the left-right direction (X1-X2 direction) of the magnetic field control plate 3. Further, as shown in FIG. 6, the center line C2 indicating the center position of the orthogonal portion 1c is the same as the center line C1 indicating the center position of the magnetic sensor element 7a, and the opening width D2 of the magnetic field control plate 3 in the left-right direction is set. It is in a position to divide into two. In other words, the position of the center 1e of the orthogonal portion 1c is the same as the position of the center of the magnetic sensor element 7a, that is, the inner surface of the first end 3a of the magnetic field control plate 3, that is, the second short side 5b of the insulating substrate 5. To D2 / 2.

  On the other hand, the center line C3 that divides the width D3 of the end portion 1a of the current path 1 in the left-right direction into two is on the right side of the center line C2 that indicates the mounting position of the orthogonal portion 1c of the current path 1, as shown in FIG. . That is, the center 1b in the width direction of the end 1a of the current path 1 is closer to the second short side 5b of the insulating substrate 5 than the center 1e of the orthogonal part 1c of the current path 1.

  By the way, in the current sensor 100 through which a large current flows, the current path 1 is a primary current path through which a large current flows, and the plurality of terminals 9 are secondary current paths through which a small current power source and data flow for measurement. The distance between the primary current path and the secondary current path must be kept above a predetermined insulation distance. Therefore, in the current sensor 100 as well, in order to set the distance between the primary current path and the secondary current path to be equal to or greater than the determined insulation distance, the current sensor 100 includes a plurality of insertion pieces 1d in the current path 1 shown in FIG. A distance T1 between the insertion piece 1d closest to the terminal 9 and the terminal 9 is set to be equal to or greater than a necessary insulation distance. As a result, the current sensor 100 can maintain insulation resistance.

  As described above, the position of the center 1b in the left-right direction (X1-X2 direction), that is, the width direction of the end portion 1a of the current path 1 is set on the second short side 5b side of the insulating substrate 5 from the center 1e of the orthogonal portion 1c. Has been. By setting in this way, compared to the case where the center 1b in the width direction of the end portion 1a is set at the same position as the center 1e of the orthogonal portion 1c, the most of the plurality of insertion pieces 1d in the current path 1 is set. It becomes easy to set the distance T1 between the insertion piece 1d close to the terminal 9 and the terminal 9 to a longer distance. Therefore, it is possible to easily secure a necessary insulation distance.

  As described above, in the current sensor 100, the plurality of terminals 9 are arranged along the first short side 5 a of the insulating substrate 5, and the orthogonal portion 1 c that is a portion orthogonal to the magnetic field control plate 3 of the current path 1 in plan view. The center 1e is arranged at a position facing the magnetic sensor element 7a, and the center 1b in the width direction of the end portion 1a of the current path 1 is the second short side 5b of the insulating substrate 5 from the center 1e of the orthogonal part 1c of the current path 1. Since the current path 1 is formed so as to be on the side, the distance T1 between the current path 1 and the terminal 9 can be easily set to a longer distance. As a result, since it is possible to easily secure a necessary insulation distance, it is possible to easily reduce the size of the current sensor 100 while maintaining insulation resistance.

  The main part of the current sensor 100 including the current path 1, the magnetic field control plate 3, and the insulating substrate 5 is within the maximum outline of the housing 11 except for the insertion piece 1 d and the terminal 9. Therefore, the outer shape of the main part of the current sensor 100 excluding the insertion piece 1d and the terminal 9 is substantially the same as the maximum outer shape of the housing 11. As a result, the casing 11 does not include an extra area, and thus the current sensor 100 can be further downsized.

  Further, since the tips of both end portions 1a of the current path 1 are divided into a plurality of insertion pieces 1d, when soldering the current sensor 100 to the mother board 51, the heat of the solder is easily transmitted to the insertion pieces 1d. Moreover, it is possible to make it difficult for the heat of the solder to escape to the end portion 1a. Therefore, soldering can be facilitated.

  Next, the relationship between the current sensor 100 according to the embodiment and the upper adjacent current path 41 and the lower adjacent current path 42 that may exist outside the current sensor 100 will be described with reference to FIG.

  FIG. 7 is a schematic diagram showing the distance in the vertical direction between the constituent elements of the current sensor 100 in a state where the current sensor 100 is mounted on the mother board 51. Note that the current path 1 is indicated by a broken line for easy understanding.

  There may be an upper adjacent current path 41 and / or a lower adjacent current path 42 that generates an external magnetic field outside the current sensor 100. The upper adjacent current path 41 exists above the magnetic field control plate 3 with a distance A1. Further, the lower adjacent current path 42 exists with a distance A2 from the tip of the insertion piece 1d of the current path 1. Usually, when adjacent current paths exist above and below the current sensor 100, the distance A1 and the distance A2 are set to the same distance.

  The magnetic sensor element 7a and the upper adjacent current path 41 are separated by a distance B1 including the distance A1. There is a magnetic field control plate 3 between the magnetic sensor element 7 a and the upper adjacent current path 41. Therefore, the magnetic field control plate 3 can make it difficult to be affected by the upper adjacent current path 41 to the magnetic sensor element 7a.

  On the other hand, the magnetic sensor element 7a and the lower adjacent current path 42 are separated by a distance B2 including the distance A2. Here, both the tip of the insertion piece 1d at both ends 1a of the current path 1 and both ends of the magnetic field control plate 3, that is, the tips of the first end 3a and the second end 3b, It faces the same direction (downward). Therefore, between the magnetic sensor element 7a and the lower adjacent current path 42, there exists the insulating substrate 5 to which the sensor IC 7 and the magnetic field control plate 3 are attached, and the mother substrate 51 to which the current sensor 100 is attached. It will be.

  The magnetic field control plate 3 does not exist between the magnetic sensor element 7a and the lower adjacent current path 42. However, since the insulating substrate 5 and the mother substrate 51 exist, the magnetic sensor element 7a and the lower adjacent current path inevitably exist. The distance B2 between the road 42 can be set to a longer distance. As a result, the magnetic sensor element 7a can be less affected by the lower adjacent current path 42. The distance B2 is set to about twice the distance B1. By setting the distance B2 to be about twice the distance B1, the influence from the lower adjacent current path 42 to the magnetic sensor element 7a is reduced to the same level as the influence from the upper adjacent current path 41 to the magnetic sensor element 7a. Can be difficult to receive.

  Thus, in the current sensor 100, the tips of both ends 1a of the current path 1 and the tips of both ends of the magnetic field control plate 3, that is, the tips of the first end 3a and the second end 3b are the same. Therefore, the insulating substrate 5 and the mother substrate 51 exist in the opening direction of the magnetic field control plate 3. Therefore, the distance between the magnetic sensor element 7a and the lower adjacent current path 42 on the opening direction side of the magnetic field control plate 3 can be set to a longer distance, and from the lower adjacent current path 42 to the magnetic sensor element 7a. Can be less affected by

  In the current sensor 200, the magnetic flux generated by the current flowing through the central region that is a flat region at the center of the current path 1 passes through the central region of the magnetic field control plate 3 on the Z1 side in FIG. At the same time, the current can be accurately detected by passing through the magnetic sensor element 7a.

On the other hand, the magnetic flux generated by the current flowing through the current path extending in the Z1-Z2 direction on both sides of the central area of the current path 1 does not pass through the central area of the magnetic field control plate 3. Therefore, compared with the configuration of the comparative example shown in FIG. 14, even when a large current flows through the current path 1, the magnetic field control plate 3 is not easily saturated and high sensitivity can be obtained.
That is, according to this configuration, since the induction magnetic field passing through the central region of the magnetic field control plate 3 is reduced as compared with the comparative example, the magnetic field control plate 3 is less likely to be saturated, and a large current can be accurately measured. Further, since the magnetic flux passing through the magnetic sensor element 7a is increased, the sensitivity is increased and the small current can be accurately measured. Therefore, the measurement range (dynamic range) can be expanded.

[First Modification of the Embodiment]
Next, the configuration and operation of the current sensor 110, which is a modification of the embodiment of the present invention, will be described with reference to FIGS. Similar to the current sensor 100, the current sensor 110 is mounted on various devices and is a current sensor that measures a current flowing through the device for control and monitoring. The difference between the current sensor 110 and the current sensor 100 is only the shape of the current path 21, and the other structures are common, and therefore, description of common items may be omitted. The reference numerals used in the current sensor 100 are used as they are except for the configuration related to the current path 21.

  FIG. 8 is a perspective view showing the appearance of the current sensor 110 with the housing 11 removed, and FIG. 9 is a plan view of the current sensor 110. FIG. 10 is a schematic diagram showing the distance in the left-right direction between each component of the current sensor 110 in a state where the current sensor 110 is mounted on the mother board 51. In FIG. 10, the current path 21 is indicated by a broken line for easy understanding. 8 to 10, the current sensor 110 is shown with the housing 11 removed.

  As shown in FIG. 8, the current sensor 110 includes a current path 21 through which a current to be measured flows, a magnetic field control plate 3 that controls a magnetic field generated by the current to be measured, an insulating substrate 5 having a rectangular shape, and an insulating substrate 5. And a sensor IC 7 having a built-in magnetic sensor element 7a for measuring a magnetic field. The insulating substrate 5 is provided with a plurality of terminals 9 electrically connected to the magnetic sensor element 7a. The plurality of terminals 9 are arranged along the first short side 5 a which is one short side of the insulating substrate 5, and are attached to the insulating substrate 5 via the pedestal 13. Further, the tips of both end portions 21a of the current path 21 are divided into a plurality of insertion pieces 21d.

  As shown in FIGS. 9 and 10, the width D <b> 6 of the orthogonal portion 21 c formed in the current path 21 when the current path 21 and the magnetic field control plate 3 are orthogonal to each other is the width of both end portions 21 a of the current path 21. It is formed narrower than D5. Since the width D6 of the orthogonal part 21c of the current path 21 is narrower than the width D5 of the end part 21a of the current path 21, the magnetic flux from the current path 21 concentrates on the orthogonal part 21c of the current path 21, and the sensitivity is increased. Can be high. Therefore, the structure of the current sensor 110 is effective when the current to be measured is a small current.

  Thus, by setting the width D6 of the orthogonal part 21c of the current path 21 to be narrower than the width D5 of the end part 21a of the current path 21, the magnetic flux from the current path 21 concentrates on the orthogonal part 21c of the current path 21. The detection sensitivity can be increased.

  In the current sensor 110, the magnetic sensor element 7a is disposed at the center 3d of the opening width D2 of the magnetic field control plate 3, and the center 21e of the orthogonal portion 21c that is a portion orthogonal to the magnetic field control plate 3 of the current path 21 in plan view. Is disposed at a position facing the magnetic sensor element 7a, and the center 21b in the width direction of the end 21a of the current path 21 is closer to the second short side 5b of the insulating substrate 5 than the center 21e of the orthogonal part 21c. Similar to the current sensor 100. Therefore, the effect that the insulation distance in the current sensor 110 can be easily secured is the same as that of the current sensor 100.

[Second Modification of this Embodiment]
FIG. 11 is an external view of a current sensor 400 according to a second modification of the embodiment of the present invention. FIG. 12 is a diagram for explaining the magnetic field generated in the current sensor 400 shown in FIG.

  The current sensor 400 includes a current path 201 through which a current to be measured flows, a magnetic field control plate 203 that controls a magnetic field (induction magnetic field) generated by the current to be measured through the current path 201, and a magnetic sensor element 207a that measures the magnetic field. ing.

The current path 201 includes a first current path 221 and a second current path 222 extending in the Z2 direction from the one end of the first current path 221 with an inclination of approximately 90 ° with respect to the first current path 221. A third current path 233 extending in the Z2 direction with an inclination of approximately 90 ° from the other end of the first current path 221 toward the side where the second current path 222 extends with respect to the first current path 221; Have
The second current path 222 and the third current path 233 are provided on the same side with respect to the plane including the first current path 221.
The current path 201 has a U shape, and the first current path 221, the second current path 222, and the third current path 223 are substantially perpendicular to each other. The angle between the first current path 221 and the second current path 222 and the third current path 223 may be other than a right angle.

The magnetic field control plate 203 includes a first magnetic field control plate 231 and a second magnetic field extending in the Z2 direction with an inclination of approximately 90 ° with respect to the first magnetic field control plate 231 from one end of the first magnetic field control plate 231. In the Z2 direction with an inclination of approximately 90 ° from the other end of the first magnetic field control plate 231 toward the side where the second magnetic field control plate 232 extends with respect to the control plate 232 and the first magnetic field control plate 231. And a third magnetic field control plate 233 extending.
The magnetic field control plate 203 has a U shape, and the first magnetic field control plate 231, the second magnetic field control plate 232, and the third magnetic field control plate 233 are substantially perpendicular to each other. The angle between the first magnetic field control plate 231 and the second magnetic field control plate 232 and the third magnetic field control plate 233 may be other than a right angle.
The first magnetic field control plate 231 is parallel to the first current path 221.

  In the current sensor 400, the second magnetic field control plate 232 from both ends of the first magnetic field control plate 231 in the Z2 direction in which the second current path 222 and the third current path 223 extend with respect to the first current path 221. The third magnetic field control plate 233 extends. That is, the ends of the current path 201 and the magnetic field control plate 231 are located in the same Z2 direction.

  The magnetic sensor element 207a is mounted on the insulating substrate 205, and is positioned opposite to the first current path 221 on the side opposite to the first magnetic field control plate 231 (Z1 side) with respect to the first current path 221. To do.

  As shown in FIGS. 11 and 12, the current sensor 400 has a structure in which the current path 201 and the magnetic field control plate 203 are both U-shaped and are opened in the same Z2 direction. The first current path 221 at the center of the current path 201 is flat and parallel to and faces the flat first magnetic field control plate 231 at the center of the magnetic field control plate 203.

  In the current sensor 400, as shown in FIG. 12, most of the induced magnetic field generated from the current flowing through the first current path 221 flows through the first magnetic field control plate 231. Further, since the magnetic field control plate 203 is open on the Z2 direction side of the first current path 221, the second magnetic field control that is both arms extending orthogonally to the first current path 221. Between the plate 232 and the third magnetic field control plate 233, an induced magnetic field generated from a current flowing through the current path 201 passes through the magnetic sensor element 207a, and the induced magnetic field is detected by the magnetic sensor element 207a.

  In the current sensor 400, as shown in FIG. 12, the magnetic flux 251 generated by the current flowing through the central first current path 221 flows through the current path 201 by passing through the magnetic sensor element 207a in the X2 direction. Current can be detected accurately.

  Further, the magnetic flux 252 generated by the current flowing through the second current path 222 flows in the X1 direction on the front side of the sheet of FIG. Then, it bends in the X2 direction, passes through the second magnetic field control plate 232 in the thickness direction (X2 direction), and the magnetic flux passes through the inside or the periphery of the magnetic sensor element 207a in the X2 direction. Then, after passing through the third magnetic field control plate 233 in the thickness direction (X2 direction), bent to the front side of the paper, it flows again in the X1 direction on the front side of the paper. Similarly, the magnetic flux generated from the current flowing through the third current path also flows outside the current sensor 800 in the X1 direction, bends, and then flows inside or around the magnetic sensor element 207a in the X2 direction.

  Therefore, in the current sensor 400, the induction magnetic field that passes through the first magnetic field control plate 231 that is the central region of the field control plate is only the magnetic field generated from the current flowing through the first current path 221. That is, the magnetic field generated from the current flowing through the second current path 222 and the third current path 223 does not pass through the first magnetic field control plate 231. Compared with the current sensor 800 of the comparative example shown in FIG. 14, the induction magnetic field passing through the first magnetic field control plate 231 that is the central region of the magnetic field control plate is reduced, so that the first magnetic field control plate 231 is less likely to be saturated, It becomes possible to accurately measure a large current. Further, since the magnetic flux passing through the magnetic sensor element 207a is increased, the measurement sensitivity is increased, and a small current can be accurately measured. Therefore, the measurement range (dynamic range) can be expanded.

  As described above, the current sensor 100 and the current sensor 110 according to the embodiment of the present invention have been described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. Is possible.

1,201 Current path 1a End 1b Center 1c Orthogonal part 1d Insertion piece 1e Center 3,203 Magnetic field control plate 3a First end 3b Second end 3c Top surface 3d Center 5,205 Insulating substrate 5a First short side 5b 2nd short side 5c Long side 5d Mounting hole 7 Sensor IC
7a, 207a Magnetic sensor element 9 Terminal 11 Housing 13 Base 21 Current path 21a End 21b Center 21c Orthogonal part 21d Insertion piece 21e Center 31 Current path 31a End part 31b Center 31c Orthogonal part 31d Insertion piece 31e Center 33 Magnetic field control plate 33a First end portion 33b Second end portion 33c Top surface portion 33d Center 34 Base 35 Insulating substrate 35a Mounting hole 36 Cover 36a Fastening portion 37 Case 38 Housing 38a First short side 38b Second short side 38c Long side 39 Terminal 41 Upper adjacent Current path 42 Lower adjacent current path 51 Mother substrate 100, 110, 200, 400 Current sensor 221 First current path 222 Second current path 223 Third current path 231 First magnetic field control plate 232 Second magnetic field Control plate 233 Third magnetic field control plate

Claims (2)

A current path through which a current to be measured flows, a magnetic field control plate for controlling a magnetic field generated by the current to be measured, and a magnetic sensor element for measuring the magnetic field,
The current path includes a first current path, a second current path extending from one end of the first current path with an inclination to the first current path, and the other end of the first current path. And a third current path extending with an inclination from
The second current path and the third current path are provided on the same side with respect to a plane including the first current path,
The magnetic field control plate includes a first magnetic field control plate, a second magnetic field control plate extending with an inclination from one end of the first magnetic field control plate with respect to the first magnetic field control plate, and the first magnetic field control plate. A third magnetic field control plate extending with an inclination from the other end of the magnetic field control plate,
The second magnetic field control plate and the third magnetic field control plate are provided on the same side with respect to a plane including the first magnetic field control plate,
The magnetic sensor element is located opposite to the first current path on the side opposite to the first magnetic field control plate with respect to the first current path,
The first current path and the first magnetic field control plate are parallel to each other,
The direction in which the second current path and the third current path are provided with respect to the first current path, and the second magnetic field control plate and the third current path with respect to the first magnetic field control plate. A current sensor characterized in that the direction in which the magnetic field control plate is provided is the same. The first current path, the second current path and the third current path are at right angles;
The current sensor according to claim 1, wherein the first magnetic field control plate, the second magnetic field control plate, and the third magnetic field control plate are perpendicular to each other.

Images