JP2011185914A - Current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current sensor that is small and inexpensive and can accurately detect current to be measured using a multilayer printed wiring board. <P>SOLUTION: A coil section as a primary conductor pattern of at least one coil shape is formed in the multilayer printed wiring board, and a magnetoelectric conversion element is built. Thus, withstand insulating voltage between the primary conductor pattern and magnetoelectric conversion element is improved, the magnetic flux applied to the magnetoelectric conversion element is increased by setting the primary conductor pattern in the coil shape, the cost is reduced, and the primary conductor pattern can approach the magnetoelectric conversion element. Therefore, the accuracy can be increased. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a current sensor including a magnetoelectric conversion element and a coiled primary conductor pattern in a multilayer printed wiring board.

  Conventionally, as a method for measuring a current to be measured in a non-contact manner, there is generally a method using a magnetic core. In a current sensor using a magnetic core, the magnetic core is installed so as to surround a conductor through which a current to be measured flows, and a magnetic circuit is formed together with a gap portion provided in the magnetic core. The magnitude of the current to be measured is measured in a non-contact manner by measuring the magnitude of the magnetic flux generated in the magnetic circuit by the current to be measured through the magnetoelectric conversion element installed in the gap portion.

  In recent years, a coreless type current sensor that does not use a magnetic core has been proposed for the purpose of miniaturization, weight reduction, and high accuracy. As a coreless type current sensor, there is one in which a Hall element is installed on a metal U-shaped primary conductor via a shield layer (see, for example, Patent Document 1).

  As another coreless type current sensor, a magnetoelectric conversion element is installed in the vicinity of the U-shaped portion of the U-shaped primary conductor bent in a crank shape, and the U-shaped primary conductor and the magnetoelectric conversion element are arranged. There is one in which ferromagnetic materials are arranged substantially in parallel so as to sandwich both of them (see, for example, Patent Document 2).

  JP 2008-545964 A   Japanese Patent Laid-Open No. 5-223849

Problems to be solved by the invention

  The coreless type current sensor disclosed in Patent Document 1 has a structure in which the primary conductor cross-sectional area is reduced in the vicinity of the Hall element to obtain a high current density in order to obtain a high magnetic flux density in the vicinity of the Hall element. However, when the cross-sectional area is rapidly reduced and the current density is increased, heat is generated in the primary conductor particularly in the vicinity of the Hall element, and the operation of the Hall element becomes unstable due to the generated heat.

  In the coreless type current sensor disclosed in Patent Document 2, ferromagnetic materials are arranged substantially in parallel so as to sandwich the U-shaped primary conductor and the magnetoelectric conversion element. It is configured to collect magnetic flux. However, there is no particular disclosure about the means for installing the magnetoelectric conversion element and the ferromagnetic material, the space for ensuring insulation, and the shield layer, and there are many problems in miniaturization, cost reduction, and high accuracy. There was a problem.

  The present invention has been made in order to solve the above-described problems. The dielectric breakdown voltage between the magnetoelectric conversion element and the primary conductor is easily secured, and electric field noise from the primary conductor is removed or reduced, so that the measurement range can be reduced. Therefore, an object of the present invention is to obtain a current sensor that can be easily varied, can accurately detect even a small current to be measured, and is small in size and low in cost.

Means for solving the problem

  A current sensor according to the present invention is a multilayer printed wiring board in which electronic layers, semiconductor elements, and the like are built in which conductor layers and insulating layers are alternately laminated. The semiconductor element is at least one magnetoelectric conversion element. Magnetoelectric conversion elements are arranged in or near at least one coil-shaped primary conductor pattern provided on the wiring board.

  In addition, the current sensor according to the present invention is provided in a multilayer printed wiring board with a conductive layer disposed on at least one upper layer of the electronic component built-in surface having a magnetoelectric conversion element and at least one lower layer of the electronic component built-in surface having the magnetoelectric conversion element. And a shield layer having a ground potential is installed.

  The current sensor according to the present invention is an inner layer surface of at least one multilayer printed wiring board located between the electronic component built-in surface having the magnetoelectric conversion element and the coiled primary conductor pattern arrangement surface in the multilayer printed wiring board. In addition, a shield layer having conductivity and ground potential is provided.

  In the current sensor according to the present invention, the first connection thin wire conductor and the second connection thin wire conductor are arranged in a non-linear manner, and the installation interval between the first thin wire conductor and the second thin wire conductor is reduced. It is arranged in.

  In addition, the current sensor according to the present invention includes at least two coil portions, and one coil portion is a stacked coil portion disposed so as to surround the other coil portion, and these coil portions are electrically Is connected to.

  The current sensor according to the present invention is provided with an electrical branch point at at least one point of the coil portion.

  The current sensor according to the present invention is a sensor in which a depletion layer is provided in the same layer as or in the vicinity of the magnetoelectric conversion element, and a ferromagnetic material is provided in at least one of the depletion layers.

  In the current sensor according to the present invention, the ferromagnetic material provided in at least one of the depletion layers has a substantially trapezoidal shape.

  The current sensor according to the present invention is a multilayer printed wiring board in which a connector for connecting an electronic component and an external terminal installed on the multilayer printed wiring board including at least one magnetoelectric conversion element is installed. is there.

  The current sensor according to the present invention is a multilayer printed wiring board in which at least one magnetoelectric conversion element is a Hall IC.

  Further, in the current sensor according to the present invention, in the multilayer printed circuit board, the built-in electronic component is two Hall ICs, and includes the differential output means of the two Hall ICs, and the coil portion is at the middle point of the coil. The Hall IC is installed in each coil part that has an electrical branch point and is divided at the branch point.

  The current sensor according to the present invention is a multilayer printed wiring board, and the built-in electronic components are two Hall ICs, and includes differential output means of the two Hall ICs, and at least two of the multilayer printed wiring board have It is provided with separated coil parts, and Hall ICs are installed in the respective coil parts.

The invention's effect

  As described above, according to the present invention, the coiled primary conductor pattern is formed on the multilayer printed wiring board, and the magnetoelectric transducer is incorporated in the multilayer printed wiring board different from the coiled primary conductor pattern forming surface. In addition, the withstand voltage between the coiled primary conductor pattern and the magnetoelectric conversion element is improved, the magnetic flux density generated by making the primary conductor pattern coiled can be increased, and the primary conductor pattern and the magnetoelectric conversion element can be approached. Therefore, a small-capacity current to be measured can be detected with high accuracy, and the coil is manufactured in the manufacturing process of the multilayer printed wiring board, so that the cost can be reduced.

  Also, by placing a shield layer on at least one upper layer and at least one lower layer of the electronic component built-in surface having the magnetoelectric conversion element so as to be positioned between the magnetoelectric conversion element and the primary conductor pattern forming surface, There is an effect of removing or reducing electric field noise from the primary conductor pattern toward the magnetoelectric transducer due to the primary conductor pattern. In addition, by providing a shield layer having electrical conductivity and a ground potential in at least one upper layer and at least one lower layer of the primary conductor pattern, electric field noise applied to the magnetoelectric transducer from outside is reduced. There is an effect of removing or reducing.

  Also, by installing the shield layer on the inner layer of the multilayer printed wiring board, the process of installing the shield layer can be simplified, and the cost can be reduced.

  Moreover, by making the primary conductor into a coil shape, there is an effect that the magnetic flux density applied to the magnetoelectric conversion element can be easily improved.

  Also, because the coiled primary conductor pattern is produced on the multilayer printed wiring board, the installation position of the primary conductor pattern, the number of turns of the coil, and the winding density can be easily changed compared to the use of metal wires. Has the same effect that the current detection range can be varied. Also, by providing a plurality of coiled primary conductor patterns on the same multilayer printed wiring board and changing the connection point according to the measured current capacity, the multilayer printed wiring board and the magnetoelectric transducer remain the same, and the current detection range There is an effect that can be varied.

  Furthermore, by installing a ferromagnetic material in the depletion layer of the multilayer printed wiring board inner layer, the installation of the magnetic material is simplified, and there is an effect that it can approach the magnetoelectric conversion element and can easily collect magnetism, There is an effect that it is possible to accurately detect a small current to be measured.

  Furthermore, when a programmable Hall IC is used for the magnetoelectric conversion element, sensitivity and temperature characteristics can be adjusted only by electrical adjustment, so that adjustment as a current sensor can be simplified, and the cost can be reduced. .

  Furthermore, two Hall ICs are used for the magnetoelectric conversion element, a branch point is provided in the coiled primary conductor pattern, and the two Hall ICs are arranged in the respective coil portions, so that each of the two Hall ICs has a reverse direction. Since a magnetic flux can be applied, a uniform external magnetic field can be removed by taking the differential output of both, and there is an effect that the accuracy can be improved.

  Furthermore, two Hall ICs are used for the magnetoelectric conversion element, and at least two separated coil parts are provided in the multilayer printed wiring board. Hall ICs are installed in the respective coil parts, and each of the two Hall ICs has a reverse direction. By applying magnetic flux and taking the differential output of both, a uniform external magnetic field can be removed, and the accuracy can be improved.

It is a perspective view of the current sensor by Embodiment 1 of this invention. It is a top view of the current sensor by Embodiment 1 of this invention. It is sectional drawing of the current sensor by Embodiment 1 of this invention. It is a perspective view which shows the outline of the coil part periphery of the current sensor by Embodiment 1 of this invention. It is a top view of a part of current sensor by Embodiment 1 of this invention. It is a top view of a part of another current sensor by Embodiment 1 of this invention. It is sectional drawing of another current sensor by Embodiment 1 of this invention. It is a top view of the current sensor by Embodiment 2 of this invention. It is a perspective view which shows the outline of the coil part periphery of the current sensor by Embodiment 2 of this invention. It is a perspective view which shows the outline of the coil part periphery of another current sensor by Embodiment 2 of this invention. It is a perspective view which shows the outline of the coil part periphery of another electric current sensor by Embodiment 2 of this invention. It is a perspective view which shows the outline of the coil part periphery of another electric current sensor by Embodiment 2 of this invention. It is a top view of the current sensor by Embodiment 3 of this invention. It is sectional drawing of the current sensor by Embodiment 3 of this invention. It is a perspective view which shows the outline of the coil part periphery of the current sensor by Embodiment 3 of this invention.

Embodiment 1 FIG.
1 is a perspective view of a current sensor according to Embodiment 1 of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a cross section showing an AA ′ cross section (XZ plane) in FIGS. FIG. In the figure, the current sensor 1 is composed of a multilayer printed wiring board 2 having a coil portion 3, which is a coiled primary conductor pattern, a Hall IC 4, and a shield layer 5.
In the first embodiment, the multilayer printed wiring board 2 in which the conductor layers and the insulating layers are alternately laminated has the six inner layers 8, and the coil portion 3 that is a coiled primary conductor pattern has the inner layer 8a. And a plurality of fine wire conductors 9 provided in 8f are sequentially connected via connection thin wire conductors 10. The multilayer printed wiring board 2 incorporates a Hall IC 4 as one magnetoelectric conversion element. A connector 7 is installed on the upper surface of the multilayer printed wiring board 2 as an input / output terminal of the current sensor. A shield layer 5 is provided on the inner layers 8 b and 8 e of the multilayer printed wiring board 2.

First, the configuration of the multilayer printed wiring board 2 will be described.
FIG. 3 is a cross-sectional view showing the AA ′ cross section (XZ plane) in FIGS. 1 and 2 of the multilayer printed wiring board 2. In recent years, with the increasing demand for multi-functionality, miniaturization, and thinning of electronic devices, development and practical application of component-incorporated wiring technology are progressing. Part of this technique is also used in this embodiment. The component-embedded wiring board has progressed from the fabrication of embedded passive components such as capacitors, resistors, and inductors to the embedded technology of active components such as bare chips and packages. In this embodiment, the Hall IC 4 that is an active component is used. Built-in board. A Hall IC is a bare chip or packaged IC in which a Hall element and a processing circuit are integrated. By using a programmable Hall IC, adjustment of sensitivity, temperature characteristics, etc. can be performed only by electrical adjustment. Since the adjustment as the current sensor can be simplified, the use of the Hall IC has an effect of reducing the cost. A cavity 13 for embedding the Hall IC 4 is provided in the insulating layer 12 sandwiched between the inner layers 8c and 8d, and the Hall IC 4 is installed. In the present embodiment, the insulating layer 12 is an electronic component built-in layer. The form of the Hall IC 4 may be a bare chip or a package product, but it is desirable that the Hall IC 4 be a bare chip rather than a package product in order to reduce the thickness. In addition, the portion where the Hall IC 4 is embedded is an insulating layer in the present embodiment, but is not limited to the insulating layer, and may be a copper core instead of the insulating layer. By using a copper core, it is possible to expect an improvement in heat dissipation characteristics and an electric field shielding effect. The connection between the Hall IC 4 and the multilayer printed wiring board 2 is made by bumps made of metal formed on the Hall IC 4 although not particularly shown in the drawing. The material of the bump is, for example, gold or solder. Although the bump formation method varies depending on the material, there are a printing method, a plating method, a ball mounting method, a stud bump, and the like. The side electrically connected to the multilayer printed wiring board 2 may be either the upper or lower conductor layer when the Hall IC 4 is installed on the insulating layer, but if it is installed on the copper core, the copper core Since it is not desirable from the viewpoint of insulation to provide a conductor layer on the top, it is desirable to connect to the upper conductor layer. The Hall IC 4 and the multilayer printed wiring board 2 can be connected by wire bonding, but it is advantageous to use bumps for miniaturization. Although input / output of the Hall IC 4 is not particularly shown, it is taken out from the upper surface of the multilayer printed wiring board 2 through a through via. In this embodiment, as shown in FIG. 1, it is configured to be connected to an external device or the like via the connector 7. However, the present invention is not limited to this, and a terminal may be provided and connected to the outside by soldering or the like. Good.

  On the second inner layer 8b and the fifth inner layer 8e of the multilayer printed wiring board 2, a conductive shield layer 5a and a shield layer 5b are provided, respectively. The shield layer 5a and the shield layer 5b remove or reduce electric field noise applied to the Hall IC 4 mainly due to the coil portion 3 which is a coil-shaped primary conductor pattern as noise that degrades the performance as a current sensor. Therefore, it is desirable to install at least one layer between the Hall IC 4 and the coil unit 3. In order to remove or reduce the electric field noise applied to the Hall IC 4 not only from the coil unit 3 but also from the outside more effectively, or to remove or reduce the electric field noise emitted from the coil unit 3 to the outside, A shield layer may be provided on the front and back surfaces of the multilayer printed wiring board 2. The material of the shield layer 5 is only required to be conductive. For example, copper, aluminum and the like are conceivable, and the shield layer 5 is connected to an electrical ground provided on the multilayer printed wiring board 2. In the present embodiment, only the Hall IC 4 is installed as a built-in component. However, when other circuit components are installed, they are arranged between the two shield layers 5a and 5b as much as possible as in the Hall IC 4. Is desirable.

  As shown in FIG. 4, the coil part 3 which is a coil-shaped primary conductor pattern which applies a to-be-measured electric current has the shape of a solenoid coil. The coil portion 3 includes a thin wire conductor portion 9a (one-dot chain line in FIG. 4) provided on the first inner layer 8a of the multilayer printed wiring board 2, a thin wire conductor portion 9b (solid line in FIG. 4) provided on the sixth inner layer 8f, The connecting thin wire conductor portions 10a and 10b (dotted lines in FIG. 4) for electrically connecting the thin wire conductor portions of the layers are provided and integrated with the multilayer printed wiring board 2. The connecting thin wire conductor is a through via or a through hole having conductivity in the printed circuit board manufacturing process. As shown by the broken line in FIG. 2, the shape of the coil portion 3 is sawtooth when viewed from the Z direction, and the Hall IC 4 is a coil in the coil near the center line 11 of the coil portion 3 in this embodiment. It is installed at the end. The Hall IC 4 is installed at the end of the coil for the convenience of input / output routing of the Hall IC 4. However, the installation position of the Hall IC 4 is not limited to this, and depending on the magnetic flux density to be applied to the Hall IC 4, the outside of the coil may be installed. Alternatively, it may not be near the center line 11 of the coil portion 3. The number of turns of the coil part 3 and the width and thickness of the thin wire conductor part are determined according to the measured current value to be applied, and the arrangement of the coil part 3 with respect to the installation position of the Hall IC 4 has been briefly described above. It is determined according to the magnetic flux density to be applied to the IC 4, that is, the magnitude of the current to be measured. The magnetic flux density desired to be applied to the Hall IC 4 is configured to adjust the magnetic flux density desired to be applied to the Hall IC 4 by changing only the arrangement and shape of the coil part 3 as much as possible. The installation position of the Hall IC 4 and the inner layer thickness of the multilayer printed wiring board 2 do not change even if the magnitude of the current to be measured changes, and can be fixed, that is, by reducing the variable parameters, the manufacturing process can be simplified, Cost reduction. For the input / output of the current to be measured, the coil portion input / output end 6 connected to the coil portion 3 through a through via or a through hole is used. In particular, a terminal or the like is not provided, but the present embodiment is not limited to this, and a conductive terminal or connector may be used for connection.

  FIG. 5 is a plan view showing a part of the thin wire conductor portion 9b and the connecting thin wire conductor portion 10a provided in the sixth inner layer 8f of the multilayer printed wiring board 2. FIG. In the present embodiment, as can be seen from FIG. 2 and FIG. 4, the connecting thin wire conductors 10 are arranged in a straight line. However, the present invention is not limited to this, and the connecting thin wire conductor portions 10 may be arranged in a staggered manner instead of being arranged in a straight line as in another plan view shown in FIG. By arranging them in a staggered manner, it is possible to reduce the interval between the thin wire conductor portions 9b, and consequently, the coil can be closely wound and the number of turns can be increased.

Next, the operation of the current sensor 1 will be described with reference to FIG.
When a current to be measured is applied to the coil part input / output ends 6a to 6b of the coil part 3 which is a coil-shaped primary conductor pattern, a magnetic flux vector 14 indicated mainly by an arrow in FIG. Generated according to the magnitude of the current to be measured. Here, for the sake of simplicity, only one main magnetic flux vector applied to the Hall IC 4 is shown. In the present embodiment, a magnetoelectric conversion element that measures magnetic flux in the Y direction, that is, has a magnetosensitive direction in the in-plane direction is used. When the Hall IC 4 is installed at the position shown in FIG. 4, the magnetic flux vector 14 shown in FIG. 4 is applied to the Hall IC 4 in the direction of magnetic sensing. In order to apply a large magnetic flux density to the Hall IC 4 without changing the position and the number of turns of the coil unit 3, the Hall IC 4 may be installed inside the coil unit 3, and in order to apply a small magnetic flux density, the coil unit 3 may be provided outside of the hall IC 4. In order to apply a smaller magnetic flux density, it is preferable to install the coil unit 3 away from the center line 11.

FIG. 7 is a cross-sectional view of a current sensor having an overlapping coil portion 15 that is another coil-shaped primary conductor pattern in Embodiment 1 of the present invention. FIG. 7 shows a configuration in which only the overlapping coil portion 15 is added as compared with FIG. 3 described above, and the redundant portions in other configurations and operations are omitted.
As can be seen from the plan view of FIG. 2 and the perspective view of FIG. 4, in the previous example, only one coil portion 3, which is a coiled primary conductor pattern, was provided on the multilayer printed wiring board 2. As described above, in another example, the overlapping coil portion 15 that is also a coil-shaped primary conductor pattern is provided so as to surround the coil portion 3. Similar to the coil part 3, the overlapping coil part 15 is a fine wire conductor part 9c (not visible in the cross section of FIG. 7) provided in the seventh inner layer 8g of the multilayer printed wiring board 2, and a thin wire provided in the eighth inner layer 8h. The conductor portion 9d and the connecting thin wire conductor portions 10c and 10d that electrically connect the thin wire conductor portions of both layers are provided and integrated with the multilayer printed wiring board 2. The two coiled primary conductor patterns of the coil part 3 and the overlapping coil part 15 are in the same winding direction, and the two coil parts are connected so that the current to be measured flows in the same direction, so that each coil is inside the coil part. The magnetic flux density generated at the part is added. That is, the magnetic flux density applied to the Hall IC 4 increases. Thus, the magnetic flux density applied to the Hall IC 4 can be varied even with the same measured current.

  As described above, according to the first embodiment, the coil portion, which is a coil-shaped primary conductor pattern, is formed on the multilayer printed wiring board by using the thin wire conductor portion in the inner layer of the multilayer printed wiring board and the connecting thin wire conductor portion. The built-in Hall IC, which is a magnetoelectric conversion element, improves the withstand voltage between the primary conductor pattern and the Hall IC, and the multilayer printed wiring compared to the case where the coil and Hall IC are separated. Since the substrate can be reduced and the cost can be reduced, the coil portion and the Hall IC can be brought close to each other, and the primary conductor pattern is formed in a coil shape.

  In addition, by installing a shield layer on the multilayer printed wiring board inner layer between the Hall IC and the coil part of the coil-shaped primary conductor pattern, the electric field noise from the primary conductor pattern mainly due to the primary conductor pattern to the Hall IC direction Has the effect of removing or reducing.

  In addition, since the coil part, which is a coiled primary conductor pattern, is produced on the multilayer printed wiring board, the installation position of the coil part and the number of turns can be changed, and the addition of the coil part is easier than using a metal conductor winding. There is an effect that the current detection range can be changed while the specifications such as the sensitivity and the installation position of the Hall IC are the same.

  Furthermore, since a programmable Hall IC is used for the magnetoelectric conversion element, sensitivity and temperature characteristics can be adjusted only by electrical adjustment, so that adjustment as a current sensor can be simplified and there is an effect of cost reduction.

Embodiment 2. FIG.
FIG. 8 shows a plan view of a current sensor according to Embodiment 2 of the present invention. FIG. 9 shows a coil portion 3, a coil portion input / output end portion 6, and a Hall IC 4 which are the coil-shaped primary conductor patterns in FIG. FIG. 6 is a perspective view showing a branching portion 16 and an input / output thin wire conductor portion 17. The cross-sectional view showing the AA ′ cross section (XZ plane) in FIG. Here, the current sensor includes a coil section 3, a Hall IC 4, a shield layer 5 (not shown in FIG. 9), a branch section 16, and an input / output thin wire conductor section 17, and a multilayer having an input / output end section 6 on the surface. The printed wiring board 2 is used.
In the second embodiment, compared with the first embodiment, the coil portion 3 which is a coiled primary conductor pattern is provided with a branch portion 16 serving as an electrical branch point, and the input / output thin wire conductor portion 17 and the coil portion are inserted. The configuration is such that the current to be measured can be input / output via the branching portion 16 using the output end 6c, and the redundant portions in other configurations and operations are omitted.

By providing the branch portion 16 and installing the three coil portion input / output ends 6a, 6b, 6c on the multilayer printed wiring board 2, the input / output of the current to be measured becomes three. That is, when the coil portion input / output ends 6a and 6b, which are equivalent to the first embodiment, are used and the current to be measured is applied to the entire coil portion 3, the coil portion input / output ends 6a and 6c are used. 9, the current to be measured is applied only to the front (front) side of the coil portion 3 in FIG. 9, and the current to be measured is applied only to the rear side of the coil portion 3 in FIG. 9 using the coil input / output ends 6 b and 6 c. There are three ways to apply.
First, a case where the coil input / output ends 6a and 6b are used will be described. In this case, the current to be measured is applied to the entire coil unit 3, and the magnetic flux density applied to the Hall IC 4 installed inside the coil unit 3 is the largest. Next, a case where the coil input / output ends 6b and 6c are used will be described. In this case, the current to be measured is applied only to the rear part of the coil part 3, and the magnetic flux density applied to the Hall IC 4 installed inside the coil part 3 is smaller than that in the above case. Finally, a case where the coil input / output ends 6a and 6c are used will be described. In this case, the current to be measured is applied only to the front portion of the coil portion 3, and no current to be measured is applied to the coil portion surrounding the Hall IC 4 installed at the rear portion of the coil portion 3. The applied magnetic flux density is further reduced compared to the case described above. In other words, the magnetic flux density applied to the Hall IC 4 can be varied by changing only the connection of the coil input / output end without greatly changing the configuration, and thus the measurable rating as a current sensor can be changed. It becomes.

FIG. 10 shows another embodiment of the second embodiment of the present invention. In a current sensor having two Hall ICs, a coil portion 3 which is a coiled primary conductor pattern, and a coil portion input / output end portion 6 is a perspective view showing the Hall IC 4, the branching portion 16, and the input / output thin wire conductor portion 17. Here, the current sensor includes a coil portion 3, a Hall IC 4, a shield layer 5 (not shown in FIG. 10), a branch portion 16, an input / output thin wire conductor portion 17, and a multilayer having a coil portion input / output end portion 6 on the surface. It is composed of a printed wiring board.
FIG. 10 shows a configuration in which two Hall ICs 4 are installed as compared with FIG. 9, and duplicated portions in other configurations and operations are omitted.

  The operation of the current sensor in FIG. 10 will be described. The coil to be measured is input using the coil input / output end 6c, and the coil input / output ends 6a and 6b are used for output. The measured current input to the coil input / output end 6c flows through the input / output thin wire conductor 17 and reaches the branching portion 16 and is divided at the branching portion 16. Applied to the front (front) part of the coil part 3 and the rear part of the coil part 3, the magnetic flux vector 14a generated at the front part is in the -Y direction, and the magnetic flux vector 14b generated at the rear part is in the + Y direction. That is, the magnetic flux in the reverse direction is applied to the individual Hall ICs 4a and 4b installed on the front side and the rear side of the coil part 3, respectively.

  Output as a current sensor is performed by taking the differential output of the two Hall ICs 4. Since magnetic fluxes in opposite directions are applied to the individual Hall ICs 4, positive and negative and reverse outputs are obtained from the individual Hall ICs 4. Therefore, by performing differential processing, the output of the sensor is doubled and in phase. Uniform external magnetic field effects and noise are eliminated. Therefore, it is possible to increase the accuracy of the sensor output. It is desirable to install the additional circuit for differential processing on the electronic component built-in surface on which the Hall IC 4 is installed. However, if it is difficult to install the electronic component built-in surface due to the dimensions and circuit scale of the additional circuit component, a multilayer It is installed on the front surface or the back surface of the printed wiring board 2 and connected to the Hall IC 4 by through vias or the like. When the additional circuit is provided on the outer layer (front surface) of the multilayer printed wiring board 2, it is desirable to add an inner layer between the coil unit 3 and the additional circuit installed on the surface and newly install a shield layer. The installation of the shield layer has an effect of removing or reducing electric field noise from the coil unit 3 to the additional circuit due to the coil unit 3.

FIG. 11 shows still another embodiment of the second embodiment of the present invention. In a current sensor having two coil portions 3, a coil portion 3 which is a coiled primary conductor pattern, and a coil portion input / output end FIG. 6 is a perspective view showing a portion 6, a Hall IC 4, and an input / output thin wire conductor portion 17. Here, the current sensor includes a coil portion 3, a Hall IC 4, a shield layer 5 (not shown in FIG. 11), an input / output thin wire conductor portion 17, and a multilayer printed wiring board provided with a coil portion input / output end portion 6 on the surface. Composed.
FIG. 11 is a configuration in which two branching portions 16 are not provided and the two coil portions 3 are provided separately from each other, and the coil portion input / output end 6 is provided in each coil portion 3 as compared with FIG. The part which overlaps with the structure and operation | movement of is abbreviate | omitted.
In FIG. 10, which is the previous form, the current to be measured is divided by the branching section 16. In FIG. 11, which is the present embodiment, the coil part 3 is divided into separate parts, the front part being a coil part 3a, the rear part being a coil part 3b, and the coil part 3a having coil part input / output ends 6a and 6c. The coil portion 3b has coil portion input / output end portions 6b and 6d. The coil unit input / output ends 6c and 6d are used for inputting the current to be measured to the coil units 3a and 3b, and the coil unit input / output ends 6a and 6b are used for the output. That is, in FIG. 10, the current to be measured is divided at the branching section 16, but in FIG. 11, the current to be measured is shunted outside the multilayer printed wiring board, and the current to be measured after the shunting is supplied to each of the coil portions 3a, It is the structure applied to 3b. The advantage of shunting externally is that heat generation is suppressed when a large current to be measured before shunting is applied to the input / output thin wire conductor portion 17. It is also conceivable that the accuracy of the diversion can be improved by diverting outside.
Although the description has been made on the premise of shunting, in FIG. 11, if the current to be measured is input to the coil input / output end 6c and the coil input / output ends 6a and 6d are connected, for example, 2 The two coil parts 3a and 3b are serially connected, and the current to be measured having the same capacity is applied to the two coil parts 3a and 3b. When the current to be measured has a low capacity, it is desirable to apply the current to be measured having the same capacity by connecting the two coil portions 3a and 3b serially without dividing the current.
In the present embodiment, the winding direction of the two coil portions 3 is the same, and the current to be measured is applied in the opposite direction. However, the present invention is not limited to this. The current to be measured may be applied to the circuit. It is desirable to select in consideration of simplification of the routing of the input / output thin wire conductor portion 17.

FIG. 12 shows still another embodiment of the second embodiment of the present invention. In a current sensor having two coil portions 3, a coil portion 3 which is a coiled primary conductor pattern, and a coil portion input / output end FIG. 6 is a perspective view showing a portion 6, a Hall IC 4, and an input / output thin wire conductor portion 17. Here, the current sensor includes a coil portion 3, a Hall IC 4, a shield layer 5 (not shown in FIG. 12), an input / output thin wire conductor portion 17, and a multilayer printed wiring board having a coil portion input / output end portion 6 on the surface. Composed.
FIG. 12 is a configuration in which two separate coil portions 3 are arranged side by side in the X-axis direction as compared with FIG. 11, and each coil portion 3 is provided with a coil portion input / output end 6. The part which overlaps with another structure and operation | movement is abbreviate | omitted.
In FIG. 11, which is the previous form, the configuration is such that two separate coil portions 3 are arranged side by side in the Y-axis direction. In FIG. 12, which is the present embodiment, the configuration is such that two separate coil portions 3 are arranged side by side in the X-axis direction. In FIG. 12, coil portion input / output ends 6a and 6c are used for inputting currents to be measured to the respective coil portions 3a and 3b, and coil portion input / output ends 6b and 6d are used for output. An advantage of arranging the coil portions 3a and 3b side by side in the X-axis direction is that magnetic fluxes generated in the respective coil portions and applied to the respective Hall ICs are hardly interfered with each other. When arranged in the Y-axis direction, since the end surfaces of the coil portions are close to each other, the magnetic fluxes generated in the vicinity of the end surfaces of the coil portions become vectors in opposite directions, so that they interfere with each other and are reduced.
Although description has been made on the premise of shunting, in FIG. 12, for example, if a current to be measured is input to the coil input / output end 6c and the coil input / output ends 6a and 6d are connected, 2 The two coil parts 3a and 3b are serially connected, and the current to be measured having the same capacity is applied to the two coil parts 3a and 3b. When the current to be measured has a low capacity, it is desirable to apply the current to be measured having the same capacity by connecting the two coil portions 3a and 3b serially without dividing the current.
In the present embodiment, the winding direction of the two coil portions 3 is the same, and the current to be measured is applied in the opposite direction. However, the present invention is not limited to this. The current to be measured may be applied to the circuit. It is desirable to select in consideration of simplification of the routing of the input / output thin wire conductor portion 17.

  As described above, according to the second embodiment, the coil portion, which is the coiled primary conductor pattern, is provided with a branch portion serving as an electrical branch point, and the input / output thin wire conductor portion and the coil portion input / output end portion are provided. By using it, the current to be measured can be input and output through the branching section, so that the magnetic flux density applied to the Hall IC can be varied while the configuration of the multilayer printed wiring board and the installation position of the Hall IC remain the same. There is an effect that the detection range can be varied.

  In addition, two Hall ICs are used for the magnetoelectric conversion element, and a coil part that is a coiled primary conductor pattern is provided with a branch part that serves as an electrical branch point, and each coil part divided at the branch part is reversely directed. Since the current to be measured flows, the magnetic flux in the opposite direction can be applied to each of the two Hall ICs. By taking the differential output of both, uniform external magnetic field effects, noise, etc. can be eliminated, and high accuracy There is an effect that can be made.

  In addition, when two Hall ICs are used for the magnetoelectric conversion element, Hall ICs are provided in each of the two coil portions that are the coil-shaped primary conductor patterns, and when magnetic fluxes in opposite directions are applied to the two Hall ICs, By taking the differential output, the effect of uniform external magnetic field, noise and the like can be removed, and there is an effect that the accuracy can be improved.

Embodiment 3 FIG.
13 is a plan view of a current sensor according to Embodiment 3 of the present invention, FIG. 14 is a cross-sectional view showing a BB ′ cross section (XZ plane) in FIG. 13, and FIG. 15 is a coil-shaped primary in FIG. It is a perspective view which shows the coil part 3, the coil part input / output end part 6, Hall IC4, and the ferromagnetic material 18 which are conductor patterns. A sectional view showing an AA ′ section (XZ plane) in FIG. 13 is the same as FIG. In the figure, a current sensor 1 includes a coil portion 3, a Hall IC 4, a shield layer 5 (not shown in FIG. 15), a ferromagnetic material 18, and a multilayer printed wiring board 2 having a coil portion input / output end 6 on its surface. Consists of.
The third embodiment is a configuration in which a ferromagnetic material 18 is newly added to the cavity 13 of the insulating layer 12 that is the electronic component built-in surface as compared with the first embodiment. Is omitted.

The configuration of the multilayer printed wiring board 2 and the ferromagnetic material 18 will be described.
FIG. 14 is a cross-sectional view showing a BB ′ cross section (XZ plane) in FIG. 13 of the multilayer printed wiring board 2. A cavity 13 which is a depletion layer for embedding the ferromagnetic material 18 is provided in the insulating layer 12 sandwiched between the inner layers 8c and 8d, and the ferromagnetic material 18 is provided. In the present embodiment, an example is shown in which the insulating layer 12 is an electronic component built-in surface, and the ferromagnetic material 18 is installed on the same electronic component built-in surface as the Hall IC 4. This is because the magnetic sensing direction of the Hall IC 4 to be used is the Y direction, and it is desirable to install the same on the same electronic component built-in surface as in this example. However, the present invention is not limited to this example. When it is difficult to install the ferromagnetic material 18 such as when an electronic component other than the Hall IC is installed on the same electronic component built-in surface as the Hall IC 4, the cavity 13 is provided in another layer. Although the ferromagnetic material 18 may be installed, it is desirable that it be as close as possible to the electronic component built-in surface where the Hall IC 4 is installed.
Further, the cavity 13 may be configured to be closed by the electronic component built-in surface, that is, a configuration in which the ferromagnetic material 18 is completely taken into the multilayer printed wiring board 2. The structure open | released by 2 side surfaces may be sufficient. The closed configuration has the advantage that the ferromagnetic material 18 is protected from the external environment, and the open configuration allows the ferromagnetic material 18 to be replaced according to the magnetic flux density desired to be applied to the Hall IC 4. As a result, the measurable rating of the current sensor can be varied.
The ferromagnetic material 18 may be a bulk material such as permalloy, but is not limited thereto, and an amorphous magnetic material that can be formed in a foil shape may be used. As for the installation method, the ferromagnetic material 18 can be easily bonded. However, when the cavity 13 has an open configuration, resin sealing of the open portion may be used.
The shape of the ferromagnetic material 18 is a trapezoidal shape in the present embodiment, and the magnetic flux vector 14 is concentrated on the side of the Hall IC 4 where the side is narrowed, and a larger magnetic flux density is obtained at the position of the Hall IC 4. However, the present invention is not limited to this embodiment, and the degree of concentration of the magnetic flux vector 14 is reduced, but it is easy to manufacture. From the viewpoint of cost reduction or the like, a rectangular shape may be used, and the magnetic flux density obtained at the position of the Hall IC 4 can be adjusted depending on the shape.

  Prior to the description of the operation of the current sensor in FIG. 15, FIG. 4 which is Embodiment 1 without the ferromagnetic material 18 will be described. In the absence of the ferromagnetic material 18, the magnetic flux density applied to the Hall IC 4 is only the magnetic flux vector 14 generated in the vicinity of the center line 11 of the coil part 3 in which the Hall IC 4 is installed. On the other hand, when the ferromagnetic material 18 is installed as shown in FIG. 15, magnetic flux vectors (for example, 14 b and 14 c) generated outside the vicinity of the center line 11 of the coil portion 3 are also collected in the ferromagnetic material 18 to form holes. By being applied to the IC 4, the magnetic flux density is increased. In this way, even with the same current to be measured, the magnetic flux density applied to the Hall IC 4 can be easily increased by installing the ferromagnetic material 18.

  As described above, according to the third embodiment, by installing the ferromagnetic material in the cavity of the multilayer printed wiring board, the installation of the magnetic material is simplified and the magnetic flux can be easily collected with respect to the Hall IC. There is an effect that it is possible to accurately detect a small current to be measured.

  In addition, since the cavity 18 is open at the side surface of the multilayer printed wiring board 2, it is easy to replace the ferromagnetic material 18. As a result, the measurable rating as a current sensor can be varied.

DESCRIPTION OF SYMBOLS 1 Current sensor, 2 multilayer printed wiring board, 3 coil part, 4 Hall IC, 5 shield layer, 6 coil part input / output end part, 7 connector, 8 inner layer, 9 fine wire conductor part, 10 connection fine wire conductor part, 11 center line , 12 Insulating layer, 13 cavity, 14 magnetic flux vector, 15 overlapping coil part, 16 branching part, 17 input / output thin wire conductor part, 18 ferromagnetic material

Claims (13)

In a multilayer printed wiring board in which conductor layers and insulating layers are alternately stacked, including electronic components and semiconductor elements,
The semiconductor element is at least one magnetoelectric conversion element, is configured by winding a conductor, and includes a coil portion provided on the multilayer printed wiring board,
The coil portion includes a plurality of first thin wire conductor portions arranged substantially parallel to one surface of the insulating layer, a plurality of second thin wire conductor portions arranged substantially parallel to the other surface of the insulating layer, and the multilayer print. A first connecting thin wire conductor portion that penetrates the wiring board and electrically connects one end portions of the first thin wire conductor portion and the second thin wire conductor portion, and the first thin wire passes through the multilayer printed wiring board. Having a second connecting thin wire conductor that electrically connects the other ends of the second thin wire conductor adjacent to the conductor and the second thin wire conductor to which the one ends are connected;
A current sensor, wherein the coil portion is disposed so as to surround the magnetoelectric conversion element. In the multilayer printed wiring board, the semiconductor element is at least one magnetoelectric conversion element, is configured by winding a conductor, and includes the coil portion provided in the multilayer printed wiring board,
A current sensor, wherein the magnetoelectric conversion element is disposed apart from the coil portion.   In the multilayer printed wiring board, the at least one upper layer of the electronic component built-in surface having the magnetoelectric conversion element and the at least one lower layer of the electronic component built-in surface having the magnetoelectric conversion element have conductivity and a ground The current sensor according to claim 1, wherein a shield layer having a potential is provided.   In the multilayer printed wiring board, at least one inner layer surface of the multilayer printed wiring board located between the electronic component built-in surface having the magnetoelectric conversion element and the primary conductor pattern has conductivity and has a ground potential. The current sensor according to claim 1, wherein a shield layer is provided.   In the multilayer printed wiring board, the first connection thin wire conductor and the second connection thin wire conductor are arranged in a non-linear manner, and the installation intervals of the first thin wire conductor and the second thin wire conductor are reduced and arranged densely. The current sensor according to any one of claims 1 to 4, wherein:   In the multilayer printed wiring board, at least two of the coil portions are installed, and one of the coil portions is a stacked coil portion arranged so as to surround the other coil portion, and these coil portions are electrically The current sensor according to claim 1, wherein the current sensor is connected to the current sensor.   The current sensor according to claim 1, wherein an electrical branch point is provided at at least one point of the coil portion in the multilayer printed wiring board.   2. The multilayer printed wiring board according to claim 1, wherein a depletion layer is provided in a layer that is the same as or close to the installation layer of the magnetoelectric conversion element, and a ferromagnetic material is provided in at least one of the depletion layers. Item 8. The current sensor according to Item 7.   9. The current sensor according to claim 1, wherein in the multilayer printed wiring board, a ferromagnetic material disposed in at least one of the depletion layers has a trapezoidal shape.   2. The multilayer printed wiring board according to claim 1, further comprising a connector for connecting an external component and an electronic component installed on the multilayer printed wiring board including at least one magnetoelectric conversion element. The current sensor according to 9.   11. The current sensor according to claim 1, wherein at least one of the magnetoelectric conversion elements is a Hall IC in the multilayer printed wiring board.   In the multilayer printed wiring board, the electronic component is two Hall ICs and includes differential output means of the two Hall ICs, and the coil portion has an electrical branch point at a midpoint, and the branch The current sensor according to claim 11, wherein the Hall IC is installed in each coil part divided at points.   In the multilayer printed wiring board, the electronic component is two Hall ICs, and includes differential output means of the two Hall ICs, and at least two separated coil portions are installed in the multilayer printed wiring board. The current sensor according to claim 11, wherein the Hall IC is installed in each coil part.

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