Current detection device

Abstract

A current sensing device is provided, including: a laminate having a plurality of insulating layers laminated therein; a current sensing element provided in an inner layer of the laminate; a current wire configured to flow current to the current sensing element, the current wire being provided above an interlayer insulating layer with respect to the current sensing element; a plurality of current vias configured to connect the current sensing element and the current wire in such a manner as to penetrate the interlayer insulating layer; and a voltage sensing via configured to obtain a voltage drop in the current sensing element, the voltage sensing via being electrically connected to the current sensing element.

Description

Technical area

[0001] The present invention relates to a current detection device. State of the art

[0002] Conventionally, a current detection device is proposed that includes a resistive element-accommodating substrate in which a resistive current detection element is integrated into a laminate of a plurality of insulating layers (ceramic layers) (see, for example, Patent Literature 1, Patent Literature 2).

[0003] In Patent Literature 1, a metal via is embedded in a via penetrating the layered insulating layers so that it can be connected to the electrodes of a resistor to increase the heat dissipation effect of the resistor integrated in the layered substrate.

[0004] Patent Literature 2 describes the similar structure to that described in Patent Literature 1, in which the number of a plurality of first (second) detection via conductors arranged in a predetermined direction is set such that the plurality of first (second) detection via conductors are arranged in a parallel circuit without adjusting a diameter of each of the first (second) detection via conductors, whereby the width W of a resistive film of a resistor is artificially increased to artificially adjust the width of the resistive film.

[0005] This technique may make it possible to design the resistance value of the current sensing resistor provided for the laminate without requiring a change in the diameter of both the first and second sensing via conductors connected to the resistive film included in the current sensing resistor. Literature listPatent literature Patent literature 1: JP 2014 - 239 142 A Patent literature 2: JP 2015 - 2 333 A Summary of the inventionTechnical problem

[0006] As described above, integrating the resistor into the substrate is now a widely used technique to try to reduce the size of the current detecting device, and since a thick conductive pattern has been successfully formed as an inner layer, instead of using a shunt resistor mounted on the substrate, a technique of integrating a shunt resistor having a relatively high amount of current flow into a layered substrate has been discussed.

[0007] However, tracing current waveforms and voltage detection patterns in such a conventional current detection device with the resistor mounted on the substrate for appropriate use of the shunt resistor has been investigated, while a suitable voltage detection structure and the improvement of current detection accuracy with respect to such a structure in a current detection device with a resistor integrated in the substrate have hardly been proposed.

[0008] JP 2015-2333 A discloses a current sensing device comprising: a laminate having a plurality of insulating layers laminated therein; a current sensing element provided in an inner layer of the laminate; a current wire configured to allow current to flow to the current sensing element, the current wire being provided above an interlayer insulating layer with respect to the current sensing element; a plurality of current vias configured to connect the current sensing element and the current wire by penetrating the interlayer insulating layer; and a voltage sensing via configured to maintain a voltage drop in the current sensing element, the voltage sensing via being electrically connected to the current sensing element. A current sensing device is also disclosed in DE 10 2014 113 313 A1.

[0009] It is an object of the present invention to improve the current detection accuracy in the current detection device using the resistor integrated in the substrate. Solution to the problem

[0010] The object is achieved by providing a current detection device having the features of claim 1. Advantageous embodiments emerge from the subclaims.

[0011] According to one aspect of the present invention, there is provided a current detection device including: a laminate having a plurality of insulating layers laminated therein; a current detection element provided in an inner layer of the laminate; a current wire configured to flow current to the current detection element, the current wire being provided above an interlayer insulating layer with respect to the current detection element; a plurality of current vias configured to connect the current detection element and the current wire so as to penetrate the interlayer insulating layer; and a voltage detection via configured to achieve a voltage drop in the current detection element, the voltage detection via being electrically connected to the current detection element.

[0012] Preferably, the current sensing device further includes a voltage wire connected to the current wire through the voltage sensing via.

[0013] Preferably, the plurality of current vias includes a proximal via located near a resistive element of the current sensing element.

[0014] The voltage sensing via may be arranged to at least partially overlap the proximal via.

[0015] It is preferable that the proximal via and the voltage sensing via are connected to each other with the power wire interposed therebetween.

[0016] The proximal via may have a larger diameter than the voltage sense via.

[0017] The present patent specification contains the disclosure of JP 2018 - 172 587, which forms the basis of the priority claim of the present application. Effects of the invention

[0018] According to the present invention, it is possible to improve the current detection accuracy in a current detection device using a resistor integrated in the substrate. Brief description of the drawings Fig. 1 is an exploded perspective view showing an exemplary configuration of a current detecting device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the structure of Fig. 1. Fig. 3 is a perspective view showing an exemplary configuration of a layer having current wires formed therein. Fig. Figure 4A is a perspective view showing an exemplary configuration of a shunt resistor and vias. Fig. 4B is a view showing an exemplary positional relationship between the current via and the voltage detection via of Fig. 4A shows. Fig. 5 is a functional block diagram showing an exemplary circuit arrangement of the current detecting device. Fig. 6 is a perspective view of the structure of Fig. 4A according to initial further training. Fig. 7 is a perspective view of the structure of Fig. 4A according to a second training course. Fig. 8 is a perspective view of the structure of Fig. 4A according to a third further training. Description of embodiments

[0019] Hereinafter, a current detecting device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0020] Fig. 1 is an exploded perspective view showing an exemplary configuration of a current detecting device according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the structure of Fig. 1. Fig. 4A is a perspective view showing an exemplary configuration of a layer having current wires formed therein. Fig. 4 is a perspective view showing an exemplary configuration of a passive device, e.g., a shunt resistor, and vias. Fig. 4B is a view showing an exemplary positional relationship between the current via and the voltage detection via of Fig. 4A shows.

[0021] As in Fig. 1, Fig. 2 and Fig. As shown in Fig. 3, a current detection device A according to the present embodiment is formed as a ceramic laminate in which a plurality of insulating layers, for example, a plurality of green ceramic layers 11, ..., 17, 21, 31 made of a ceramic material mainly containing barium oxide, silicon dioxide, alumina, etc., are laminated in this order from the bottom and then fired. It should be noted that, in addition to the ceramic material, a resin multilayer substrate formed by stacking a plurality of resin-based substrates can be used to constitute the present invention.

[0022] A base substrate B is formed, for example, by a laminate of green ceramic layers 11-1, 2, 3, ..., n (where n is an integer equal to or greater than 1). In the base substrate containing this laminate, the green ceramic layers 11-3, ..., n each have openings 15-3, ..., n in their respective regions, which, when laminated, are aligned.

[0023] As described above, not all raw ceramic layers 11-1, 2, 3, ..., n always have the openings. As in Fig. 1, for example, the raw ceramic layers 11-1, 2 have no opening in the bottom layers. In this case, a shunt resistor 1 is arranged in an opening 15 of a second base substrate B2, which is located on a first base substrate B1 without an opening 15.

[0024] The shunt resistor 1 is embedded in the openings 15-3, ..., n and above the green ceramic layers 11-1, 2. The shunt resistor 1 includes, for example, a resistive element 3 and a first electrode 5a and a second electrode 5b connected to both ends of the resistive element 3.

[0025] The first electrode 5a and the second electrode 5b are made of an electrically conductive metal material such as Cu. A metal material such as a Cu-Ni-based metal material, a Cu-Mn-based metal material, or a Ni-Cr-based metal material may be used as a material for the resistive element 3. The shunt resistor 1 may be made of a single metal containing a Cu-Ni-based metal material or may have a film structure made of a resistive metal material. Together, they are referred to as a current sensing element.

[0026] Furthermore, the green ceramic layers 17, 21, 31, and the like are arranged on the green ceramic layers 11-1 to 11-n to form the laminate. Thus, the shunt resistor 1 is provided in the inner layer of the laminate.

[0027] After the above structure is formed, the pressing and low-temperature firing processes are performed to bond the green ceramic layers. Adding glass to the green ceramic layers enables firing at a relatively low temperature of about 800°C. Thus, the bonding firing process can be performed after the shunt resistor 1 and the metal wires containing Ag or the like, which will be described later, have been formed.

[0028] A first current wire 41a and a second current wire 41b are formed in the region on the green ceramic layer 17 containing the first electrode 5a of the shunt resistor 1 and in the region on the green ceramic layer 17 containing the second electrode 5b of the shunt resistor 1, respectively. The first current wire 41a and the second current wire 41b are formed, for example, by screen printing.

[0029] In the region on the green ceramic layer 17 where the first electrode 5a and the first current wire 41a are stacked in the stacking direction, electrically conductive vias (e.g., also referred to as metal vias, conductor vias) 18a-1, 2, 3, ..., 18a-9 (collectively referred to as 18a) are formed, which are individually embedded in a plurality of through holes (ie, contact holes: CH).

[0030] Furthermore, in the region on the green ceramic layer 17 where the second electrode 5b and the second current wire 41b are stacked in the stacking direction, electrically conductive vias 18b-1, 2, 3, ... 18b-9 (collectively designated by 18b) are formed, which are separated from each other in the planar direction of the green ceramic layer 17 and individually embedded in a plurality of through holes, each having a relatively small area. The current vias are collectively designated by reference numeral 18.

[0031] The electrically conductive vias can be formed, for example, by using a hole-forming tool with needle-like elements arranged thereon to punch through-holes in the raw ceramic layer 17 and by supplying electrically conductive material into the through-holes.

[0032] As described above, the raw ceramic layers 17, 21 may each also function as an interlayer insulating layer between the wires and the shunt resistor.

[0033] The green ceramic layer 21 consists of layered layers 21-1, 21-2, ... 21-m of the green ceramic layers. The layered layers 21-1, 21-2, ... 21-m each have via conductors 23-1a to 23ma and via conductors 23-1b to 23mb, respectively, provided at the positions corresponding to the current vias 18a-2 and 18b-2 in the vertical direction, respectively. The via conductors 23-1a to 23ma and the via conductors 23-1b to 23mb are each electrically connected to voltage wires 33a, 33b provided on the green ceramic layer 31.

[0034] The number of vias 18a, 18b can be selected. For example, the vias 18a, 18b can be arranged in the form of 3 × 3 or 7 × 3, for example. Hereinafter, the vias 18a, 18b are referred to as “current vias.” Furthermore, examples of the in-plane arrangement of the plurality of current vias can include, for example, the arrangement with predetermined distances between the current vias in the directions parallel to and perpendicular to the longitudinal direction of the shunt resistor 1 (ie, in the electrode-resistor-electrode arrangement direction). In the Fig. In the example shown in Figure 1 and in the following examples, the arrangement in the form of 3 × 3 is described as the basic example.

[0035] As also in Fig. As shown in Fig. 2, the plurality of current vias 18 provide electrical connection between the first electrode 5a and the first current wire 41a, and electrical connection between the second electrode 5b and the second current wire 41b. This configuration enables the shunt resistor 1 to detect current flowing through the first current wire 41a and the second current wire 41b. The via conductors 23-1a to 23-ma and the via conductors 23-1b to 23-mb separately form voltage detection vias 19. One of the voltage detection vias 19 is formed by laminating in an approximately straight line with the current via 18a-2 with the first current wire 41a interposed therebetween.The other of the voltage detecting vias 19 is formed by layering in an approximately straight line with the current via 18b-2 with the second current wire 41b interposed therebetween.

[0036] As described above, a large number of current vias 18 formed in the green ceramic layer 17 provide electrical connection between the electrodes of the shunt resistor 1 and the current wires 41a, 41b with the insulating green ceramic layer 17 interposed therebetween, thereby allowing a large amount of current to stably flow in the shunt resistor 1.

[0037] Thus, it is possible to stably operate the current detection device A and improve the reliability of the operation of the current detection device A. Furthermore, it is possible to improve the current detection accuracy of the current detection device A.

[0038] Fig. 4A is a perspective view showing an exemplary detailed configuration of the shunt resistor 1 and the current vias 18. Fig. 4A also illustrates voltage sensing vias configured to obtain a voltage drop across the first electrode 5a and the second electrode 5b. Fig. 4B is a view showing an exemplary positional relationship between the current via and the voltage detection via of Fig. 4A shows.

[0039] Fig. 4A illustrates, in a left-half area, a via structure in which the power wire 41a is shown by the dashed line, and, in a right-half area, a via structure in which the power wire 41b is shown by the solid line and the voltage wire 33b is shown by the dashed line. This illustration also relates to Fig. 6 to Fig. 8. The vias 18 located under the power wire 41 are current vias. In this structure, the current vias 18 and the voltage sensing vias 19 are stacked in the layering direction of the green ceramic layer 17, with the power wires 41a, 41b interposed between them.

[0040] The voltage sensing vias 19 are layered, for example, on respective current vias located in the closest position to the resistive element 3 of the shunt resistor 1, more specifically, on the proximal vias 18a-2 and 18b-2, which are each one of the proximal vias 18a-1 to 18a-3 and one of the proximal vias 18b-1 to 18b-3.

[0041] Subsequently, voltage wires 33a, 33b are formed on the voltage sensing vias 19. This configuration allows the voltage sensing vias 19 to be arranged in the closest position to the resistive element 3 in both the first electrode 5a and the second electrode 5b. Accordingly, the distance between each voltage sensing via 19 and the resistive element 3 can be reduced, and the influence of the temperature coefficient of electrical resistance (TCR) by the electrodes 5a, 5b, made of Cu, for example, of the shunt resistor 1 can be reduced. Fig. 4B illustrates a positional relationship between the voltage sensing via 19 and the current via 18 located under the voltage sensing via 19. Fig. 4B(a) shows an example in which the voltage detection via 19 and the current via 18 are offset from each other in the X direction. However, the current detection accuracy can be maintained because the voltage detection via 19 and the current via 18 share an overlapping portion. Fig. 4B(b) shows an example in which the voltage detection via 19 and the current via 18 are offset from each other in the Y direction and do not share an overlapping portion. Although this is omitted in the drawing, the voltage detection via 19 and the current via 18 are conductively connected via the wire 41. It is preferable that the current detection via 19 is connected to the portion in the electrode 5 as close as possible to the resistive element 3. However, in the structure of the example, Fig. 4B(b) Current flows through the Cu-made wire 41, which forms the current path by the amount of offset from the current via 18, so that the voltage detection via is substantially connected at the position separated from the resistive element 3. This structure may be affected by, for example, the temperature coefficient of electrical resistance (TCR) of the wire 41 and is therefore not preferable for detecting a current with high accuracy.

[0042] Fig. Fig. 5 is a functional block diagram showing an exemplary circuit arrangement of the current detection device, and illustrates an example of the state in which the shunt resistor 1 is mounted. The shunt resistor 1 is arranged between the wires 41a, 41b formed on the green ceramic layer 17. The voltage wires 19, 19 for measuring the voltage are connected to the electrodes 5a and 5b of the shunt resistor 1, respectively. The other ends of the voltage wires 19, 19 are connected to an integrated circuit (IC). Although they are Fig. 1, Fig. 2 etc. is omitted, it is noted that the integrated circuit (IC) may be built-in or integrated with the current detection device A including the laminate, or may be a separate component from the current detection device A. The integrated circuit (IC) may be connected to the current detection device A by wires. These components as a whole constitute a current detection module X. The integrated circuit (IC) includes, for example, an A / D conversion circuit 63, an amplifier circuit 65, and a microcomputer 67, and outputs a signal to various devices according to a voltage signal. This structure can constitute the current detection module X capable of measuring the current flowing through the wires 41a, 41b of the shunt resistor 1.

[0043] As described above, according to the present embodiment, it is possible to improve the current detection accuracy in the current detection device using the shunt resistor integrated into a substrate. Furthermore, it is possible to improve the reliability of the current detection device. Furthermore, it is possible to reduce the influence of the temperature coefficient of electrical resistance (TCR).

[0044] Further developments of the current detection device of the present embodiment will be described below. (First training)

[0045] Fig. Fig. 6 is a perspective view showing the structure of the shunt resistor and the vias in the current detecting device according to a first development of the present embodiment, Fig. 4A. As described in Fig. As shown in Figure 6, according to the first embodiment, the diameter R2 of the voltage sensing via 19 is smaller than the diameter R1 (this reference symbol is shown in Figure 18-7) of the current via 18a-2. The same applies to the current via 18b-2.

[0046] This configuration makes it possible to easily arrange the current detection via 19 within the plane of the current via 18, and even if the relative position between the voltage detection via 19 and the current via 18 as they are layered is slightly offset in the plane direction of the green ceramic layer (17), it is possible to reduce the influence on the current detection accuracy caused by the offset. (Second training)

[0047] Fig. Fig. 7 is a perspective view showing the structure of the shunt resistor and the vias in the current detecting device according to a second modification of the present embodiment, Fig. 4A, is explained.

[0048] As in Fig. As shown in Figure 7, the voltage detection via 19 according to the second embodiment is directly connected to the electrodes 5a, 5b of the shunt resistor 1, without the current wires 41a, 41b being interposed therebetween. That is, the current via 18 is not provided in the regions AR1, AR2 that are close to the resistive element 3. A plurality of current vias 18 are provided.

[0049] This embodiment has the advantage of not requiring the process of aligning the current via 18 and the voltage sensing via 19.

[0050] However, the power wires 41a, 41b each have a smaller effective connection area compared to those of the other examples of the present embodiment because a connection area for the voltage detection via 19 must be specially secured. (Third training course)

[0051] Fig. Fig. 8 is a perspective view showing the structure of the shunt resistor and the vias in the current detecting device according to a third modification of the present embodiment, Fig. 4A, is explained.

[0052] As in Fig.As shown in Figure 8, according to the third embodiment, the plurality of current vias 18 are formed, and the effective connection area of ​​the current wires 41a, 41b is secured. The voltage detection via 19 is arranged between the current via 18a-2 and the current via 18a-3 in such a way that they are separated by a distance L3 in a direction in which the connection areas between the resistive element 3 and the electrodes 5a, 5b extend. The voltage detection via 19 on the electrode 5b side is arranged in the same way.

[0053] Since the plurality of current vias 18 are formed in the above configuration, a stable current path can be ensured. Furthermore, since the voltage detection via 19 does not overlap with the current via 18a-2 or with the current via 18a-3, the above configuration has the advantage of not requiring alignment of the current via 18 and the voltage detection via 19. However, the current detection accuracy in the third modification is lower than that in the other examples of the present embodiment.

[0054] In the above embodiments, the configurations and the like shown in the accompanying drawings are not limitative and can be changed as needed within the scope of the present invention. Various other modifications can be made and implemented as needed without departing from the scope of the object of the present invention. The individual components of the present invention can be added or omitted as needed, and an invention provided with the added or omitted configuration is also included in the present invention. Industrial applicability

[0055] The present invention can be used in a current detection device. List of reference symbols A current measuring device B Base substrate X Current detection module 1 shunt resistor 3 resistive element 5a first electrode 5b second electrode 11-n, ..., 1 raw ceramic layer (insulating layer) for base substrate 15-3, ... n opening 17, 21 Raw ceramic layer (interlayer insulating layer) 18a-1, 2, 3, ..., 9 current through-hole 18b-1, 2, 3, ..., 9 current via 18a-1, 2, 3 proximal via 18b-1, 2, 3 proximal via 19 Voltage sensing via 31 Raw ceramic layer (upper insulating layer for the formation of voltage wires) 33a first voltage wire 33b second voltage wire 41a first power wire 41b second power wire

[0056] All publications, patents and patent applications cited in this patent specification are incorporated herein in their entirety by reference.

Claims

[1] Current detection device (A) comprising: a laminate having a plurality of insulating layers laminated therein; a current detection element provided in an inner layer of the laminate, the current detection element being arranged in an opening (15) formed in the insulating layers, the current detection element comprising a resistive element (3) and electrodes (5a, 5b) connected to both ends of the resistive element (3); a current wire (41a, 41b) configured to allow current to flow to the current detecting element, the current wire (41a, 41b) being provided over an interlayer insulating layer with respect to the current detecting element; a plurality of current vias (18) configured to connect the electrodes (5a, 5b) and the current wire (41a, 41b) in such a way that they penetrate the interlayer insulating layer, wherein the plurality of current vias (18) comprises first current vias (18) connected to the electrodes (5a, 5b) at first positions close to the resistive element (3) and second current vias (18) connected to the electrodes (5a, 5b) at second positions farther from the resistive element (3) than the first positions; and a voltage sensing via (19) configured to receive a voltage drop in the current sensing element, wherein the voltage sensing via (19) is electrically connected to the current sensing element. [2] The current detecting device (A) according to claim 1, further comprising a voltage wire (33a, 33b) connected to the current wire (41a, 41b) through the voltage detecting via (19). [3] The current detection device (A) according to claim 1 or 2, wherein the plurality of first current vias (18) include a proximal via (18a-1, 18a-2, 18a-3, 18b-1, 18b-2, 18b-3) located near the resistive element (3) of the current detection element. [4] Current sensing device (A) according to claim 3, wherein the voltage sensing via (19) is arranged at least partially overlapping with the proximal via (18a-1, 18a-2, 18a-3, 18b-1, 18b-2, 18b-3). [5] The current detecting device (A) according to claim 3 or 4, wherein the proximal via (18a-1, 18a-2, 18a-3, 18b-1, 18b-2, 18b-3) and the voltage detecting via (19) are connected to each other with the current wire (41a, 41b) interposed therebetween. [6] Current detection device (A) according to one of claims 3 to 5, wherein the proximal via (18a-1, 18a-2, 18a-3, 18b-1, 18b-2, 18b-3) has a larger diameter than the voltage detection via (19).

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