Current detecting device

Abstract

This current detecting device comprises a resistor which has a stacked structure stacked in a thickness direction and which has a plate-shaped first electrode, a plate-shaped second electrode, and a plate-shaped resistive body disposed between the first electrode and the second electrode, and a plate-shaped first conductor connected to the resistor, and the current detecting device is connected to a power module, wherein: the power module comprises a plate-shaped second conductor connected to the resistor, and a first voltage detecting terminal and a second voltage detecting terminal; an upper surface of the first electrode and a lower surface of the first conductor on an end portion side thereof are connected to one another; a lower surface of the second electrode and an upper surface of the second conductor are connected to one another; the resistor is disposed so as to be stacked between the first conductor and the second conductor; the second voltage detecting terminal is connected to the second conductor or the second electrode; the first conductor comprises a thin plate portion having a thickness in the stacking direction that is less than a first thickness, in a region overlapping the first electrode when viewed from the stacking direction; and an upper surface of the thin plate portion and the first voltage detecting terminal are connected to one another by a wire.

Description

Current detection device

[0001] The present invention relates to a current detection device.

[0002] In recent years, as the currents used in electronic devices have become larger, there has been active development of power modules, which convert and control power by switching power semiconductors. Power modules often use high-heat-dissipation substrates capable of carrying large currents, such as ceramic substrates called DBC substrates, which are formed by directly bonding copper to an alumina substrate. In some cases, components such as power semiconductors and shunt resistors are directly mounted on plate-shaped wiring (bus bars or lead frames) made of copper or other materials.

[0003] JP 2001-358283 A JP 2022-066642 A

[0004] The current detection shunt resistor described in Patent Document 1 aims to improve heat dissipation and reliability and to shorten the wiring length, but is not suitable for passing large currents because it requires bonding and connecting multiple wires.

[0005] Therefore, in order to pass a large current through such a vertically structured shunt resistor, a surface mounting method using an L-shaped electrode member has been devised as described in Patent Document 2. Patent Document 2 describes a method for drawing out a voltage signal by wire bonding in such a configuration.

[0006] On the other hand, there is also the possibility of connecting the bus bar or lead frame directly to a vertical shunt resistor to extract current outside the power module. In this case, the method of extracting the voltage signal for accurate current detection and the method of connecting to the control circuit board become issues.

[0007] The present invention has been made to solve such problems, and aims to provide a configuration for detecting current with greater accuracy when a shunt resistor is joined to a bus bar, a lead frame, or the like.

[0008] One example of a current detection device according to the present invention is a current detection device comprising: a resistor having a laminated structure laminated in a thickness direction, the resistor having plate-shaped first and second electrodes and a plate-shaped resistive element arranged between the first and second electrodes; and a plate-shaped first conductor through which the current to be measured flows and connected to the resistor; wherein the current detection device is connected to a power module, and the power module comprises: a plate-shaped second conductor through which the current to be measured flows and connected to the resistor; and a first voltage detection terminal and a second voltage detection terminal, wherein an upper surface of the first electrode is connected to a lower surface of an end side of the first conductor, and a lower surface of the second electrode is connected to an upper surface of the second conductor, the resistor is arranged laminated between the first conductor and the second conductor, and the second voltage detection terminal is connected to the second conductor or the second electrode, and the first conductor comprises: a thick plate portion having a first thickness in the stacking direction; a thin plate portion whose thickness in the stacking direction is thinner than the first thickness in a region that overlaps with the first electrode when viewed from the stacking direction, and an upper surface of the thin plate portion and the first voltage detection terminal are connected by a wire.

[0009] In one example, the thin plate portion is provided at an end of the first conductor.

[0010] In one example, the thin plate portion has a through hole that penetrates the first conductor in the stacking direction, and the wire is connected between a side surface of the first conductor and the through hole.

[0011] In one example, the thin plate portion has a slit extending inward from a side surface of the first conductor, and the wire is connected between another side surface of the first conductor and the slit.

[0012] In one example, the thin plate portion has an extension portion extending in a lateral direction, and the wire is connected to the extension portion.

[0013] an upper surface of the first electrode is connected to a lower surface of an end of the first conductor, and a lower surface of the second electrode is connected to an upper surface of the second conductor; the resistor is disposed in a laminated structure stacked in the thickness direction, the lower surface having plate-shaped first and second electrodes and a plate-shaped resistive element arranged between the first and second electrodes; and a plate-shaped first conductor through which the current to be measured flows and connected to the resistor; wherein the current detection device is connected to a power module, and the power module includes: a plate-shaped second conductor through which the current to be measured flows and connected to the resistor; a first voltage detection terminal and a second voltage detection terminal;

[0014] In one example, the first conductor has a slit extending inward from a side surface, and the exposed portion is exposed within the slit.

[0015] In one example, the exposed portion protrudes upward from the first electrode, and a step is provided on the upper surface of the first electrode between the portion connected to the first conductor and the exposed portion.

[0016] According to the present invention, the structure in which a vertical shunt resistor is joined to a bus bar or lead frame and connected to a high-heat dissipation power module substrate is simplified, and highly accurate voltage detection is possible.

[0017] Furthermore, the shunt resistor has improved heat dissipation properties, and has excellent detection accuracy even in the case of large currents.

[0018] Furthermore, the absolute value of the temperature coefficient of resistance (TCR) can be reduced (TCR can be brought close to zero) by using a voltage extraction method, and therefore excellent detection accuracy can be achieved.

[0019] 14 is a perspective view of a configuration example of a resistor 10 according to a first embodiment of the present invention. FIG. 15 is a top view of a configuration example including a current detection device 100. FIG. 16 is a side view of the configuration of FIG. 2. FIG. 17 is a diagram illustrating control of a TCR in the current detection device 100. FIG. 18 is a top view of a modified example of the first embodiment. FIG. 19 is a top view of another modified example of the first embodiment. FIG. 19 is a side view of the example of FIG. 5A. FIG. 19 is a top view of another modified example of the first embodiment. FIG. 20 is a top view of another modified example of the first embodiment. FIG. 21 is a top view of another modified example of the first embodiment. FIG. 22 is a top view of another modified example of the current detection device 100 according to a second embodiment. FIG. 23 is a side view of the current detection device 100 according to the second embodiment. FIG. 24 is a top view of a modified example of the second embodiment. FIG. 25 is a top view of a configuration example including a current detection device 100 according to a third embodiment. FIG. 26 is a side view of a configuration example including a current detection device 100 according to a fourth embodiment. FIG. 27 is a top view of a configuration example including a current detection device 100 according to the fourth embodiment. FIG. 28 is a partially exploded view of FIG. 25. FIG. 29 is a diagram illustrating a partial configuration extracted from FIG. 26.

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. First Embodiment Fig. 1 is a perspective view of a resistor 10 according to a first embodiment of the present invention. The current detection device includes the resistor 10.

[0021] The resistor 10 has a laminated structure including a plate-shaped first electrode 12 and a plate-shaped second electrode 13, and a plate-shaped resistive element 11 disposed between the first electrode 12 and the second electrode 13, and is laminated in the thickness direction. The resistor 10 is, for example, a resistor for current detection or a shunt resistor. In particular, the resistor 10 can be said to be a shunt resistor with a vertical structure. In the example of FIG. 1, the resistive element 11 is formed in a square or rectangular shape, but the shape can be designed arbitrarily.

[0022] The material of the first electrode 12 and the second electrode 13 is a highly conductive metal material such as Cu. The material of the resistor 11 is a metal material suitable for current detection, such as a Cu-Ni system, a Cu-Mn system, or a Ni-Cr system, or a composite material containing a metal. The dimensions of the resistor 10 are, for example, 5 mm x 5 mm x 0.5 mm thick. The thicknesses of the first electrode 12 and the second electrode 13 are each, for example, 0.1 mm. The thickness of the resistor 11 is, for example, 0.3 mm.

[0023] FIG. 1 shows an example of a resistor 10, but other configurations are possible, and for example, a current detection resistor disclosed in Japanese Patent Application Laid-Open No. 2018-170478 may be used.

[0024] 2 is a top view of an example configuration including the current detection device 100. The current detection device 100 is connected to a power module 200.

[0025] The current detection device 100 includes a plate-shaped bus bar 20 (first conductor). A current to be measured flows through the bus bar 20. The bus bar 20 is connected to the resistor 10. The thickness of the bus bar 20 is, for example, 2 mm. The bus bar 20 is, for example, a U-terminal, a V-terminal, or a W-terminal of a three-phase alternating current.

[0026] 2, the resistor 10 does not actually appear, but for the sake of convenience, a pattern is added to indicate the position of the resistor 10. The position of the resistor 10 may also be indicated by the same pattern in subsequent drawings.

[0027] The power module 200 includes plate-shaped bus bars 21 and 22. The bus bar 21 is a negative terminal, and the bus bar 22 is a positive terminal. The power module 200 also includes plate-shaped wiring 23 (second conductor), wiring 24, and wiring 25. The wirings 23 to 25 are made of copper, for example, and are thick copper patterns, for example. The thickness of the wirings 23 to 25 is within a range of 0.3 mm to 0.8 mm, for example, and is 0.5 mm as a specific example. A current to be measured flows through the wiring 23. The wiring 23 is connected to the resistor 10.

[0028] The power module 200 includes one or more power devices 30. Each power device 30 is connected to wiring 23 to 25 directly or via a wire bond 40. The wire bond 40 is made of, for example, Au, Ag, Cu, Al, or the like.

[0029] The power module 200 includes a case 45, and the inside and outside of the case 45 are connected via bus bars 20 to 22.

[0030] The power module 200 includes an insulating substrate 26. The insulating substrate 26 is made of, for example, ceramics, and more specifically, silicon nitride, aluminum nitride, alumina, zirconia, or the like. In these cases, the thickness of the insulating substrate 26 is, for example, within a range of 0.1 mm to 1 mm, and a specific example is 0.3 mm. As another specific example, the insulating substrate 26 is made of glass epoxy, polyimide, or Teflon (registered trademark). In these cases, the thickness of the insulating substrate 26 is within a range of 0.4 mm to 1.6 mm, and a specific example is 1.6 mm.

[0031] The power module 200 includes a first voltage detection terminal 51 and a second voltage detection terminal 52. A voltage signal for measuring a current is output to the outside via the first voltage detection terminal 51 and the second voltage detection terminal 52. The first voltage detection terminal 51 is connected to the bus bar 20 via a wire bonding 41 (wire), and the second voltage detection terminal 52 is connected to the lower surface of the second electrode 13 or to the wiring 23 via a wiring 42 (the wiring 42 may be omitted depending on the arrangement of the second voltage detection terminal 52).

[0032] When the busbar 20 is directly connected to the resistor 10, the thickness of the busbar 20 is determined by the connection conditions between the power module 200 and external components and the current value used. Therefore, it is difficult to adjust the thickness of the busbar 20 to match the resistor 10, and a relatively thick busbar (e.g., 2 mm thick) is often connected. Using a thick busbar 20 increases the height difference between the top surface of the busbar 20 and the first voltage detection terminal 51, potentially making it difficult to perform wire bonding properly. For example, performing wire bonding at a location with a large height difference is inappropriate because it results in a steeply sloping loop shape. Furthermore, to make the slope of the loop shape more gradual, the distance between the connections must be increased, which is inappropriate because it results in a long wire. The current detection device 100 according to this embodiment aims to solve these problems.

[0033] Figure 3 shows a side view of the configuration shown in Figure 2. This side view is seen from the top of the paper in Figure 2, and therefore the left-right direction on the paper is reversed from that in Figure 2. In particular, the junction between the current detection device 100 and the power module 200 and its surroundings are shown. The wiring 23, the first voltage detection terminal 51, and the second voltage detection terminal 52 are formed on the insulating substrate 26. The resistor 10 is arranged in a stacked manner between the bus bar 20 and the wiring 23.

[0034] The resistor 10 is laminated on the upper side of the wiring 23, and in particular, the lower surface of the second electrode 13 is connected to the upper surface of the wiring 23. This connection is realized by joining using, for example, soldering, welding, low-temperature sintering, etc. It is preferable that this connection does not use wire bonding.

[0035] Furthermore, a bus bar 20 is laminated on the upper side of the resistor 10, and in particular, the upper surface of the first electrode 12 is connected to the lower surface of the bus bar 20 on the side surface 20a side. In the example of FIG. 3, the side surface 20a is the side surface that constitutes the longitudinal end of the bus bar 20. This connection is realized by joining using, for example, soldering, welding, low-temperature sintering, or the like. It is preferable that this connection does not use wire bonding.

[0036] The busbar 20 includes a thick portion 20b and a thin portion 20c. The thin portion 20c is provided on the side surface 20a of the busbar 20 (i.e., on a region including the side surface 20a or at least a portion thereof).

[0037] The thick plate portion 20b has a first thickness in the stacking direction (or thickness direction, the same applies hereinafter). The thin plate portion 20c has a thickness in the stacking direction that is thinner than the first thickness (second thickness) in a region that overlaps with the first electrode 12 when viewed from the stacking direction, and a step ΔT is formed between the upper surface of the thick plate portion 20b and the upper surface of the thin plate portion 20c.

[0038] The upper surface of the thin plate portion 20c is connected to the first voltage detection terminal 51 by wire bonding 41. By forming the thin plate portion 20c on the bus bar 20 in this way, the difference in height between the upper surface of the bus bar 20 and the first voltage detection terminal 51 in the wiring 23 is reduced, allowing for appropriate connection using short wire bonding 41. Note that the difference in height between the upper surface of the bus bar 20 and the first voltage detection terminal 51 in the wiring 23 is preferably 1.5 mm or less.

[0039] Control of the TCR in the current detection device 100 will be described using FIG. 4 . Like FIG. 3 , FIG. 4 is a view from the top of FIG. 2 , and therefore the left-right direction on the page is reversed from that in FIG. 2 . As the thin plate portion 20 c becomes thinner (or the step difference ΔT becomes larger), the connection position of the wire bonding 41 becomes closer to the resistor 11, and therefore the TCR approaches the TCR of the resistor 11. Furthermore, as the thin plate portion 20 c becomes thicker (or the step difference ΔT becomes smaller), the connection position of the wire bonding 41 becomes farther from the resistor 11, and the TCR in the current detection device 100 becomes larger due to the influence of the bus bar 20 (first conductor) made of a material with a high TCR, such as copper. In other words, the TCR can be changed by changing the thickness of the thin plate portion 20 c.

[0040] Because the current mainly flows along current path A, the current density is high near current path A and decreases as the distance from current path A increases. The current density in thin plate portion 20c decreases as it approaches side surface 20a due to its positional relationship with current path A. Due to the relationship between the current density in thin plate portion 20c and the TCR of thin plate portion 20c (busbar 20 or first conductor), the TCR in current detection device 100 can be changed by changing the connection position of wire bonding 41.

[0041] Therefore, by changing the thickness of the thin plate portion 20c (the magnitude of the step ΔT) and / or the connection position of the wire bonding 41 on the thin plate portion 20c, the temperature coefficient of resistance (TCR) of the current detection device 100 can be controlled, thereby enabling accurate current detection. For example, when the step ΔT is increased, the TCR of the current detection device 100 changes in the negative direction. Also, for example, when the connection position of the wire bonding 41 on the thin plate portion 20c is moved closer to the side surface 20a, the TCR of the current detection device 100 changes in the negative direction. The thickness of the thin plate portion 20c (the magnitude of the step ΔT) has a greater effect on the temperature coefficient of resistance (TCR) of the current detection device 100 than the connection position of the wire bonding 41 on the thin plate portion 20c.

[0042] Thus, according to the current detection device 100 of this embodiment, by changing the thickness of the thin plate portion 20c (the magnitude of the step ΔT) and / or the connection position of the wire bonding 41 on the thin plate portion 20c, the TCR of the current detection device 100 can be controlled to perform accurate current detection.

[0043] Modifications of Example 1 are shown in Figures 5A, 5B, and 6. Figures 5A and 5B are top views showing different modifications, and Figure 6 is a side view corresponding to Figure 5A. Figure 6 is a view seen from the top of Figure 5A, and therefore the left-right direction on the page is reversed from that of Figure 5A. Figure 6 shows a cross-sectional view of the bus bar 20 taken along a cross section passing through the through hole 20d. In the bus bar 20, the thin plate portion 20c has the through hole 20d penetrating the bus bar 20 in the stacking direction. The top surface of the resistor 10 (i.e., the top surface of the first electrode 12) is exposed within the through hole 20d.

[0044] In the example of FIG. 5A , the side surface 20 a refers to a side surface that constitutes a longitudinal end of the bus bar 20, and in the example of FIG. 5B , the side surface 20 a refers to a side surface that constitutes a widthwise end of the bus bar 20. Here, the “widthwise direction” refers to a direction perpendicular to both the longitudinal direction and the stacking direction. The wire bonding 41 is connected between the side surface 20 a of the bus bar 20 and the through hole 20 d. In other words, in the example of FIG. 5A , the wire bonding 41 is connected to the longitudinal end of the through hole 20 d, not to the thick plate portion 20 b side, while in the example of FIG. 5B , the wire bonding 41 is connected to the widthwise end of the through hole 20 d. This reduces the current density near the connection position of the wire bonding 41, thereby enhancing the TCR control effect.

[0045] FIG. 7 shows a top view of another modified example of the first embodiment. The thin plate portion 20c and / or the resistor 10 includes an extension portion 20e extending laterally (perpendicular to the stacking direction). In the example of FIG. 7, the extension portion 20e extends in the width direction (perpendicular to the stacking direction and also perpendicular to the longitudinal direction of the bus bar 20). A wire bonding 41 is connected to the extension portion 20e (for example, to its upper surface). In this way, the current density near the connection position of the wire bonding 41 is lowered, and the TCR control effect is enhanced.

[0046] 7, the upper surface of the extending portion 20e is covered by the bus bar 20, but in a modified example, the upper surface of the extending portion 20e may be exposed and not covered by the bus bar 20. Alternatively, in the example of FIG. 7, the resistor 10 also has an extending portion that follows the extending portion 20e, but the resistor 10 may have a rectangular shape similar to that of the first embodiment (FIG. 2).

[0047] 8A to 8C show top views of various modified examples of the first embodiment. In the example of FIG. 8A, the side surface 20a refers to a side surface that constitutes a longitudinal end of the bus bar 20, and in the examples of FIGS. 8B and 8C, the side surface 20a refers to a side surface that constitutes a widthwise end of the bus bar 20. The thin plate portion 20c has a slit 20f that extends from the side surface 20a of the bus bar 20 toward the inside of the bus bar 20. The slit 20f penetrates the bus bar 20 in the thickness direction, and the top surface of the resistor 10 (i.e., the top surface of the first electrode 12) is exposed within the slit 20f.

[0048] The wire bonding 41 is connected between the side surface of the bus bar 20 (however, a side surface different from the side surface on which the slit 20f is formed) and the slit 20f. That is, in the example of FIG. 8A , the slit 20f is formed in the side surface 20a constituting the longitudinal end of the bus bar 20, and the wire bonding 41 is connected between the slit 20f and the side surface constituting the widthwise end of the bus bar 20. In the example of FIG. 8B , the slit 20f is formed in the side surface 20a constituting the widthwise end of the bus bar 20, and the wire bonding 41 is connected between the slit 20f and the side surface constituting the longitudinal end of the bus bar 20. In the example of FIG. 8C , the slit 20f is formed in the side surface 20a constituting the widthwise end of the bus bar 20, and the wire bonding 41 is connected between the slit 20f and the side surface constituting the opposite widthwise end of the bus bar 20.

[0049] In this way, the current density in the vicinity of the connection position of the wire bonding 41 becomes lower, and the TCR control effect becomes greater.

[0050] In the example of FIG. 8A, the wire bonding 41 is connected to the first voltage detection terminal 51 side with respect to the slit 20f, but it may be connected to the opposite side of the slit 20f from the first voltage detection terminal 51.

[0051] Example 2 In Example 2, a step is formed on the first electrode 12 of the resistor 10. Example 2 will be described below, but descriptions of parts common to Example 1 may be omitted.

[0052] 9 and 10 show a configuration example including a current detection device 100 according to a second embodiment. FIG. 9 is a top view, and FIG. 10 is a side view. FIG. 10 is a view seen from the top of FIG. 9, and therefore the left-right direction on the page is reversed from that in FIG. 9. The first electrode 12 of the resistor 10 has an exposed portion 12a. The exposed portion 12a is a portion of the upper surface of the first electrode 12 that is not covered by the bus bar 20 and is exposed from the bus bar 20. The upper surface of the exposed portion 12a and a first voltage detection terminal 51 are connected by wire bonding 41.

[0053] 10 , the exposed portion 12a protrudes upward from the first electrode 12. Therefore, an electrode step 12b is provided on the upper surface of the first electrode 12 between the exposed portion 12a and the portion connected to the bus bar 20. This configuration makes it easy to position the first electrode 12 and the bus bar 20.

[0054] In the second embodiment, it is also possible to control the TCR of the current detection device 100. For example, when the step ΔT between the bus bar 20 and the exposed portion 12 a of the first electrode 12 is increased, the TCR of the current detection device 100 changes in the negative direction.

[0055] Fig. 11 shows a top view of a modified example of Example 2. The position of the exposed portion 12a is changed. That is, while the exposed portion 12a is arranged on the longitudinal side of the bus bar 20 in Example 2 (Fig. 10), the exposed portion 12a is arranged on the width side of the bus bar 20 in this modified example.

[0056] 12 shows a top view of another modified example of Example 2. Bus bar 20 has slits 20g extending inward from the side surfaces, and exposed portions 12a are exposed within slits 20g.

[0057] In the above-described second embodiment and its modified examples, it is also possible to configure the exposed portion 12a so that it does not protrude upward, that is, to configure the exposed portion 12a so that it is flush with the other portions without forming the electrode step 12b.

[0058] Example 3 is an example in which the power module 200 in Example 1 or 2 is configured by direct lead bonding. Example 3 will be described below, but descriptions of parts common to Example 1 or 2 may be omitted.

[0059] 13 is a top view of an example configuration including a current detection device 100 according to Example 3. The current detection device 100 is connected to a power module 200. The power module 200 includes a lead frame 27 (second conductor), and is connected to a resistor 10, each power device 30, and the like via the lead frame 27.

[0060] The lead frame 27 is, for example, a Cu frame, and has a thickness of, for example, 0.1 mm or more, specifically, 0.5 mm.

[0061] Resistor 10 is stacked on the upper side of lead frame 27, and in particular, the lower surface of second electrode 13 is connected to the upper surface of lead frame 27. This connection is realized by joining using soldering or welding, for example. Lead frame 27 and second voltage detection terminal 52 are connected by wire bonding 43, and the voltage on the second electrode 13 side of current detection device 100 is extracted from lead frame 27 by wire bonding 43.

[0062] Example 4 Example 4 is an example in which a printed circuit board is used as part of the power module 200 in Example 3. Example 4 will be described below, but descriptions of parts common to any of Examples 1 to 3 may be omitted.

[0063] 14 to 17 show examples of a configuration including a current detection device 100 according to Example 4. Fig. 14 is a side view (partially including a cross-sectional view), Fig. 15 is a top view, Fig. 16 is a partially exploded view of Fig. 14, and Fig. 17 is a view of a portion of the configuration extracted from Fig. 15. Fig. 14 is a view seen from the right side of the paper surface of Fig. 15.

[0064] The power module 200 includes a printed circuit board 60. A groove is formed in the lead frame 27, and the printed circuit board 60 is fitted into this groove (FIG. 16). The printed circuit board 60 includes an insulating substrate 61 (e.g., a PCB substrate) and a conductive pattern 62 (e.g., copper foil). The insulating substrate 61 has a thickness of, for example, 0.3 mm, and the conductive pattern 62 has a thickness of, for example, 18 μm.

[0065] 14 , the lower surface of the second electrode 13 of the resistor 10 is connected to the upper surface of the conductive pattern 62. This connection is realized by joining using, for example, soldering or welding. The conductive pattern 62 and the second voltage detection terminal 52 are connected by a bonding wire 43, and the voltage on the second electrode 13 side of the current detection device 100 is extracted from the conductive pattern 62 via the bonding wire 43.

[0066] In the third embodiment, the wire bonding 43 is directly bonded to the lead frame 27, but if such a configuration cannot be adopted, it is also possible to bond a printed circuit board 60 for voltage extraction and connect the wire bonding 43 to this, as in the fourth embodiment.

[0067] DESCRIPTION OF SYMBOLS 10...Resistor 11...Resistor element 12...First electrode 12a...Exposed portion 12b...Electrode step 13...Second electrode 20...Bus bar (first conductor) 20a...Side surface 20b...Thick plate portion 20c...Thin plate portion 20d...Through hole 20e...Extended portion 20f...Slit 20g...Slit 21...Bus bar 22...Bus bar 23...Wiring (second conductor) 24...Wiring 25...Wiring 26...Insulating substrate 27...Lead frame (second conductor) 30...Power device 40...Wire bonding 41...Wire bonding (wire) 42...Wiring 43...Wire bonding 45...Case 51...First voltage detection terminal 52...Second voltage detection terminal 60...Printed circuit board 61...Insulating substrate 62...Conductive pattern 100...Current detection device 200...Power module A...Current path ΔT...step

Claims

1. A current detection device comprising: a resistor having a laminated structure stacked in a thickness direction, the resistor having plate-shaped first and second electrodes and a plate-shaped resistive element disposed between the first and second electrodes; and a plate-shaped first conductor through which the current to be measured flows and connected to the resistor, wherein the current detection device is connected to a power module, and the power module comprises: a plate-shaped second conductor through which the current to be measured flows and connected to the resistor, and a first voltage detection terminal and a second voltage detection terminal, wherein an upper surface of the first electrode is connected to a lower surface of an end side of the first conductor, and a lower surface of the second electrode is connected to an upper surface of the second conductor, the resistor is stacked between the first conductor and the second conductor, and the second voltage detection terminal is connected to the second conductor or the second electrode, and the first conductor comprises: a thick plate portion having a first thickness in the stacking direction, and a thin plate portion whose thickness in the stacking direction is thinner than the first thickness within a region overlapping with the first electrode when viewed in the stacking direction, a top surface of the thin plate portion and the first voltage detection terminal are connected by a wire.

2. The current detection device according to claim 1, wherein the thin plate portion is provided at an end of the first conductor.

3. A current detection device as described in claim 1 or 2, wherein the thin plate portion has a through hole penetrating the first conductor in the stacking direction, and the wire is connected between a side surface of the first conductor and the through hole.

4. A current detection device as described in claim 1 or 2, wherein the thin plate portion has a slit extending inward from a side surface of the first conductor, and the wire is connected between another side surface of the first conductor and the slit.

5. A current detection device according to claim 1 or 2, wherein the thin plate portion has an extension portion extending in a lateral direction, and the wire is connected to the extension portion.

6. A current detection device comprising: a resistor having a laminated structure stacked in the thickness direction, the resistor having plate-shaped first and second electrodes and a plate-shaped resistive element arranged between the first and second electrodes; and a plate-shaped first conductor through which the current to be measured flows and connected to the resistor, wherein the current detection device is connected to a power module, and the power module comprises: a plate-shaped second conductor through which the current to be measured flows and connected to the resistor, a first voltage detection terminal and a second voltage detection terminal, wherein an upper surface of the first electrode is connected to a lower surface of an end side of the first conductor, and a lower surface of the second electrode is connected to an upper surface of the second conductor, the resistor is stacked between the first conductor and the second conductor, the second voltage detection terminal is connected to the second conductor or second electrode, and the first electrode has an exposed portion where a part of the upper surface of the first electrode is exposed from the first conductor, and the upper surface of the exposed portion and the first voltage detection terminal are connected by a wire.

7. The current detection device according to claim 6, wherein said first conductor has a slit extending inward from a side surface thereof, and said exposed portion is exposed within said slit.

8. A current detection device as described in claim 6 or 7, wherein the exposed portion protrudes upward from the first electrode, and a step is provided on the upper surface of the first electrode between a portion connected to the first conductor and the exposed portion.

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