Current sensor

Abstract

The current sensor may include at least one magnetoelectric conversion element, a first lead frame including a first terminal portion and a conductor portion connected to the first terminal portion, through which the measured current measured by the at least one magnetoelectric conversion element flows, a signal processing IC having at least one wiring layer for processing the signal output from the at least one magnetoelectric conversion element, and a sealing portion for sealing the at least one magnetoelectric conversion element, the conductor portion, and the signal processing IC. The at least one wiring layer may include a shielding layer made of a conductive material at a position facing the conductor portion, and the shielding layer may include a slit at a position overlapping the conductor portion in a plan view.

Description

Technical Field

[0001] The present invention relates to a current sensor.

Background Art

[0002] Patent Document 1 and Patent Document 2 describe providing a shield that shields electromagnetic noise between a bus bar or a primary conductor and a signal processing IC. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2011-112510 [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2022-23824

Summary of the Invention

Problems to be Solved by the Invention

[0003] In the current sensor as described above, even if the distance between the magnetoelectric conversion element and the lead frame is shortened, it is desired to suppress the signal processing IC from being affected by the magnetic field, electric field, and thermal stress generated by the current flowing through the lead frame.

Means for Solving the Problems

[0004] The current sensor according to one aspect of the present invention may include at least one magnetoelectric conversion element. The current sensor may include a first terminal portion and a conductor portion connected to the first terminal portion, and may include a first lead frame through which a measurement current measured by the at least one magnetoelectric conversion element flows through the first terminal portion and the conductor portion. The current sensor may have at least one wiring layer and may include a signal processing IC that processes a signal output from the at least one magnetoelectric conversion element. The current sensor may include a sealing portion that seals the at least one magnetoelectric conversion element, the conductor portion, and the signal processing IC. The at least one wiring layer may include a shield layer made of a conductive material at a position facing the conductor portion. The shield layer may include a slit at a position overlapping the conductor portion in a plan view.

[0005] In the current sensor, the magnetoelectric conversion element may be arranged on a first wiring layer of the at least one wiring layer, or it may be integrated with the signal processing IC.

[0006] In the current sensor, the magnetoelectric conversion element may be arranged on a first wiring layer among the at least one wiring layer.

[0007] In the current sensor, the at least one magnetoelectric conversion element is electrically connected to the signal processing IC via a plurality of wires, and each of the plurality of wires may be electrically connected to the signal processing IC without crossing the first lead frame in a plan view.

[0008] In any of the current sensors, the first wiring layer among the at least one wiring layer may include the shielding layer.

[0009] In any of the current sensors, the first wiring layer may be provided on the surface of the signal processing IC facing the conductor portion.

[0010] In any of the current sensors, the shielding layer does not need to be provided in the portion where the at least one magnetoelectric conversion element is installed.

[0011] In any of the current sensors, the shielding layer may be grounded.

[0012] Any of the current sensors may further include a holding portion that holds the surface of the signal processing IC opposite to the surface facing the conductor portion. The holding portion may include a holding portion that holds the signal processing IC and a side wall portion made of a conductive material that rises from the holding portion toward the conductor portion. The side wall portion may overlap the signal processing IC when viewed from a direction along the surface of the holding portion.

[0013] Any of the current sensors may further include a second lead frame electrically connected to the signal processing IC. The holding portion may be a part of the second lead frame.

[0014] In any of the current sensors, the slit may be made of an insulator.

[0015] It should be noted that the above summary of the invention does not enumerate all of its features. Furthermore, subcombinations of these features may also constitute an invention. [Brief explanation of the drawing]

[0016] [Figure 1A] This is a schematic plan view of the current sensor according to this embodiment, as seen from the ceiling side (z-axis direction). [Figure 1B] Figure 1A is a cross-sectional view of the current sensor shown along line AA. [Figure 1C] Figure 1A is a cross-sectional view of the current sensor along line BB. [Figure 2] This figure schematically shows an enlarged view of the framed area indicated by reference numeral 300 in Figure 1B. [Modes for carrying out the invention]

[0017] The present invention will be described below through embodiments of the invention, but these embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0018] Figures 1A, 1B, and 1C show the internal configuration of a semiconductor package that functions as a current sensor 10 according to this embodiment. Figure 1A is a schematic plan view of the current sensor 10 according to this embodiment, viewed from the top side (z-axis direction). Figure 1B is a cross-sectional view of the current sensor 10 shown in Figure 1A, taken along line AA. Figure 1C is a cross-sectional view of the current sensor shown in Figure 1A, taken along line BB.

[0019] In FIG. 1A, the coordinates are defined as follows: the direction parallel to the paper surface and from bottom to top is the x-axis direction, the direction parallel to the paper surface and from right to left is the y-axis direction, and the direction perpendicular to the paper surface and from back to front is the z-axis direction. Any one of the x-axis, y-axis, and z-axis is orthogonal to the other axes.

[0020] The current sensor 10 includes a signal processing IC 100, a magnetoelectric conversion element 20a, a magnetoelectric conversion element 20b, a lead frame 140 on the current conductor side, a lead frame 150 on the signal terminal side, and a sealing portion 130.

[0021] The lead frame 140 includes a conductor portion 141 and a terminal portion 142. The terminal portion 142 includes a pair of terminals 142a and 142b. The conductor portion 141 is sealed within the sealing portion 130 and partially surrounds the magnetoelectric conversion element 20a and the magnetoelectric conversion element 20b together with a part of the terminal portion 142. A measurement current flows through the terminal portion 142 and the conductor portion 141. The pair of terminals 142a and 142b are physically integrally formed with the conductor portion 141 and are exposed outside the sealing portion 130. The lead frame 140 is an example of a first lead frame.

[0022] The lead frame 140 does not necessarily need to be manufactured in a form in which a plurality of the conductor portion 141 and the terminal portion 142 are connected in series, and it may be manufactured using a form of an individualized metal part.

[0023] The lead frame 150 includes a holding portion 151 and a terminal portion 152. The terminal portion 152 includes a plurality of terminals 152a. The holding portion 151 is sealed within the sealing portion 130 and holds the signal processing IC 100. The holding portion 151 includes a holding portion 154 that holds the signal processing IC 100. The signal processing IC 100 may be fixed on the surface 154a of the holding portion 154 via an adhesive layer. The holding portion 151 includes a side wall portion 155 that rises from the holding portion 154 toward the conductor portion 141 side. The side wall portion 155 is a step formed by the holding portion 154 being recessed in a direction away from the conductor portion 141 (the bottom surface side of the sealing portion 130) in the thickness direction (z-axis direction). The side wall portion 155 may be formed by performing a semi-through machining on the lead frame 150.

[0024] The plurality of terminals 152a are configured to be physically integrally with the holding portion 151 and exposed outside the sealing portion 130. The lead frame 150 is an example of a second lead frame. The lead frames 140 and 150 may be made of a conductive material mainly composed of copper.

[0025] Here, the x-axis is a direction along the plane of the lead frames 140 and 150 and is the direction in which the plurality of terminals 152a are arranged. The y-axis is a direction along the plane of the lead frames 140 and 150 and intersects the x-axis. The y-axis is also the direction in which the plurality of terminals 152a and the pair of terminals 142a, 142b extend in a plan view. The z-axis is a direction intersecting the plane of the lead frames 140 and 150, is also a direction intersecting the circuit plane of the signal processing IC 100, and is also the thickness direction of the sealing portion 130.

[0026] The pair of terminals 142a, 142b and the plurality of terminals 152a are arranged to face each other via the signal processing IC 100 in a direction (y-axis direction) intersecting the thickness direction (z-axis direction) of the signal processing IC 100. The pair of terminals (142a, 142b) are exposed from the side surface 130a of the sealing portion 130. The plurality of terminals 152a are exposed from the side surface 130b opposite to the side surface 130a of the sealing portion 130. As shown in FIG. 1B, the pair of terminals 142a, 142b and the plurality of terminals 152a may protrude outward from different heights in the thickness direction of the sealing portion 130 of the opposing side surfaces 130a and 130b of the sealing portion 130.

[0027] The height in the thickness direction (z-axis direction) of the sealing portion 130 on the same side 1521 of the terminals 152a at the point where it intersects with the side 130b of the sealing portion 130, and the height in the thickness direction (z-axis direction) of the sealing portion 130 on the same side 1421 of the terminals 142a and 142b at the point where it intersects with the side 130a of the sealing portion 130, on the same side 1421 as the side opposite to the terminals 100a of the signal processing IC 100, may be the same. Alternatively, the height in the thickness direction (z-axis direction) of the sealing portion 130 on the side 1521 of the terminals 152a at the point where it intersects with the side 130b of the sealing portion 130 may be lower than the height in the thickness direction (Z-axis direction) of the sealing portion 130 on the side 1421 of the terminals 142a and 142b at the point where it intersects with the side 130a of the sealing portion 130.

[0028] A pair of terminals 142a and 142b protrude from the side surface 130a towards the negative side in the y-axis direction and are further bent towards the negative side in the z-axis direction. Multiple terminals 152a protrude from the side surface 130b toward the positive side in the y-axis direction and are further bent towards the negative side in the z-axis direction. A pair of terminals 142a and 142b may protrude from the side surface 130a towards the negative side in the y-axis direction and be further bent towards the positive side in the z-axis direction. Multiple terminals 152a may protrude from the side surface 130b toward the positive side in the y-axis direction and be further bent towards the positive side in the z-axis direction. A pair of terminals 142a and 142b, and multiple terminals 152a, do not have to be bent. That is, a pair of terminals 142a and 142b do not have to protrude from the side surface 130a towards the negative side in the y-axis direction and be bent towards the positive and negative sides in the z-axis direction. The multiple terminals 152a protrude from the side surface 130b toward the positive side in the y-axis direction and do not necessarily need to be bent toward the positive and negative sides in the z-axis direction.

[0029] The magnetoelectric conversion elements 20a and 20b are electrically connected to the signal processing IC 100 via a plurality of wires 22a and 22b. The magnetoelectric conversion elements 20a and 20b are configured separately from the signal processing IC 100 and output signals processed by the signal processing IC 100 to the signal processing IC 100. The signal processing IC 100 is electrically connected to a plurality of terminals 152a via wire 108. Wires 22a, 22b and wire 108 may be formed from a conductive material mainly composed of Au, Ag, Cu, or Al. The signal processing IC 100 has a plurality of pads 23a and 23b on its surface 100a, and the signal processing IC 100 is electrically connected to the magnetoelectric conversion elements 20a and 20b by connecting the plurality of pads 23a and 23b to the plurality of wires 22a and 22b.

[0030] The magnetoelectric conversion elements 20a and 20b may protrude from the surface 100a of the signal processing IC 100 such that, in a side view, the magnetosensitive surfaces of the magnetoelectric conversion elements 20a and 20b overlap with the conductor portion 141. This can increase the sensitivity of the magnetoelectric conversion elements 20a and 20b.

[0031] The magnetoelectric conversion elements 20a and 20b detect a magnetic field in a specific direction that changes according to the measured current flowing through the conductor portion 141, and the signal processing IC 100 amplifies the signal according to the magnitude of the magnetic field and outputs the amplified signal via terminal 152a. The magnetoelectric conversion elements 20a and 20b are made of compound semiconductors formed on a GaAs substrate and may be chips cut into a square or rectangular shape when viewed from the z-axis direction.

[0032] The magnetoelectric conversion elements 20a and 20b may have a substrate made of silicon or a compound semiconductor and a magnetoelectric conversion unit provided on the substrate. The thickness of the substrate is adjusted by polishing the surface on the negative side in the z-axis direction. Since a magnetic field in the z-axis direction will be detected, for example, a transverse Hall element is suitable as the magnetoelectric conversion elements 20a and 20b. Furthermore, if the magnetoelectric conversion elements 20a and 20b are positioned to detect a magnetic field in any one axis direction on the xy-plane, for example, if they are positioned to detect a magnetic field in the x-axis direction, then a magnetoresistive element or a fluxgate element is suitable as the magnetoelectric conversion elements 20a and 20b. The magnetoresistive element may be, for example, a semiconductor magnetoresistive element (SMR), an anomalous magnetoresistive element (AMR), a giant magnetoresistive element (GMR), or a tunnel magnetoresistive element (TMR).

[0033] In this embodiment, the magnetoelectric conversion elements 20a and 20b are not built into the signal processing IC 100, but are installed on the circuit surface. That is, the current sensor 10 is not a monolithic structure, with the magnetoelectric conversion elements 20a and 20b and the signal processing IC 100 being separate components. However, the magnetoelectric conversion elements 20a and 20b may be configured as a monolithic structure built into the signal processing IC 100. That is, the magnetoelectric conversion elements 20a and 20b may be integrated with the signal processing IC 100.

[0034] Furthermore, in this embodiment, an example is described in which the current sensor 10 includes two magnetoelectric conversion elements 20a and 20b. However, the current sensor 10 only needs to include one or more magnetoelectric conversion elements.

[0035] The signal processing IC 100 is a large-scale integrated circuit (LSI). The signal processing IC 100 is a signal processing circuit made of a Si monolithic semiconductor formed on a Si substrate. The signal processing circuit processes output signals corresponding to the magnitude of the magnetic field output from the magnetoelectric conversion elements 20a and 20b. Based on the output signals, the signal processing circuit corrects the measured current flowing through the conductor part 141 and outputs an output signal indicating the accurate current value via terminal 152a. Based on the difference between the output signals of the magnetoelectric conversion elements 20a and 20b, the signal processing circuit reduces the noise components contained in the output signals of the magnetoelectric conversion elements 20a and 20b, amplifies the output signals of the magnetoelectric conversion elements 20a and 20b with the noise components reduced, calculates the current value of the measured current based on the amplified output signals, and outputs an output signal indicating the current value.

[0036] In the current sensor 10 configured in this way, the magnetoelectric conversion elements 20a and 20b are electrically connected to the signal processing IC 100 via a plurality of wires 22a and 22b. When the plurality of wires 22a and 22b cross the lead frame 140 (conductor portion 141) in a plan view and are electrically connected to the signal processing IC 100, if the magnetic field changes in accordance with the change in current flowing through the lead frame 140, an induced electromotive force is generated in the loop formed by the plurality of wires 22a and 22b, which may cause an overshoot in the output of the signal processing IC 100.

[0037] On the other hand, if the magnetoelectric conversion elements 20a and 20b are arranged on the signal processing IC 100 and multiple wires 22a and 22b are electrically connected to the signal processing IC 100 without crossing the lead frame 140 (conductor portion 141) in a plan view, or if the magnetoelectric conversion elements 20a and 20b are built into the signal processing IC 100 and configured in a monolithic structure, then an induced electromotive force is generated in the loop formed by the multiple wires 22a and 22b, which prevents overshoot from occurring in the output of the signal processing IC 100.

[0038] In this embodiment, an example is described in which the magnetoelectric conversion elements 20a and 20b and the signal processing IC 100 are electrically connected to the signal processing IC 100 via a plurality of wires 22a and 22b. However, if the magnetoelectric conversion elements 20a and 20b are integrated with the signal processing IC 100, the magnetoelectric conversion elements 20a and 20b and the signal processing IC may be electrically connected by the wiring layer of the signal processing IC 100 without the use of wires.

[0039] In this configuration, the conductor portion 141 and the signal processing IC 100 overlap in a plan view. To improve the accuracy of current measurement at the magnetoelectric conversion elements 20a and 20b, it is necessary to shorten the distance between the signal processing IC 100 and the conductor portion 141. For example, if the thickness of the conductor 141 is Ta [mm], the height Tb [mm] from the surface 100a of the signal processing IC 100 to the magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b, and the distance H [mm] between the opposing surfaces between the surface 141b of the conductor 141 and the surface 100a of the signal processing IC 100, then the relationship 0.01 ≤ H ≤ Tb + 0.5 × Ta may be satisfied.

[0040] However, if the conductor part 141 is close to the signal processing IC 100, the signal processing IC 100 becomes more susceptible to the effects of the magnetic field generated when current flows through the conductor part 141. Furthermore, if the conductor part 141 is close to the signal processing IC 100, the signal processing IC 100 becomes more susceptible to the effects of the electric field generated when voltage is applied to the conductor part 141. Moreover, if the conductor part 141 is close to the signal processing IC 100, the signal processing IC 100 becomes more susceptible to the effects of thermal stress caused by the heat generated in the conductor part 141 when current flows through it.

[0041] Considering the effects described above, it is conceivable to provide a shielding layer containing conductive material on the signal processing IC 100 to reduce the influence of magnetic or electric fields. However, if a shielding layer is provided, eddy currents may be generated due to the influence of the magnetic field created by the current flowing through the conductor part 141, potentially reducing the measurement accuracy of the current flowing through the lead frame 140 measured by the magnetoelectric conversion elements 20a and 20b. In addition, if a shielding layer is provided, thermal stress caused by the heat generated in the conductor part 141 may make the signal processing IC 100 more susceptible to cracking.

[0042] Therefore, in this embodiment, the signal processing IC 100 has a shielding layer 210 containing a conductive material on a surface 100a facing the conductor portion 141. Surface 100a is also the circuit surface on which magnetoelectric conversion elements 20a and 20b are mounted. The conductive material may contain a metal such as copper. The shielding layer 210 shields electromagnetic waves. The shielding layer 210 is grounded. Furthermore, the shielding layer 210 includes a slit 212 in a position that overlaps with the conductor portion 141 in a plan view. By providing the slit 212, eddy currents generated in the shielding layer 210 can be suppressed. Furthermore, by providing the slit 212 in a position that overlaps with the conductor portion 141, the shielding layer 210 can be made less susceptible to the effects of thermal stress caused by heat generated in the conductor portion 141 when current flows through the conductor portion 141. The slit 212 is a non-shielded layer where the shielding layer 210 is not provided, and an insulating layer made of an insulating material may be provided in the slit 212 portion of the shielding layer 210.

[0043] Figure 2 is a schematic enlarged view of the frame portion indicated by reference numeral 300 in Figure 1B. The signal processing IC 100 has a plurality of wiring layers 200a, 200b, and 200c. Of the plurality of wiring layers 200a, 200b, and 200c, the wiring layer 200a that constitutes the circuit surface 100a facing the conductor portion 141 has a shield layer 210. The shield layer 210 is provided on the surface of the package of the signal processing IC 100.

[0044] The wiring layer 200a has a slit 212 made of an insulating layer in the area where the magnetoelectric conversion elements 20a and 20b are mounted. That is, the wiring layer 200a does not have a shield layer 210 in the area where the magnetoelectric conversion elements 20a and 20b are mounted. This prevents a decrease in adhesion between the magnetoelectric conversion elements 20a and 20b and the surface of the package of the signal processing IC 100. The wiring layer 200a has pads 23a and 23b around the area where the magnetoelectric conversion elements 20a and 20b are mounted (slit 212 made of an insulating layer). The wiring layer 200a has an insulating layer 214 around the pads 23a and 23b. The wiring layer 200a may be composed of a shield layer 210 in all parts except the slit 212, pads 23a and 23b, insulating layer 214, and slit 212. The slit 212 represents a region of the wiring layer 200a that is not composed of the shield layer 210, and may be made of the same insulator as the insulating layer 214.

[0045] The wiring layer 200b has vias 204a for connecting the shield layer 210 to ground, and vias 204b for connecting pads 23a and 23b to pads 202a and 202b of the wiring layer 200c. In addition to vias 204a and 204b, the wiring layer 200b also includes an insulating layer 230.

[0046] The wiring layer 200c includes the signal line 206 in addition to the pads 202a and 202b, and the portion other than the pads 202a and 202b and the signal line 206 includes an insulating layer 230.

[0047] The configuration of the multiple wiring layers 200a, 200b, and 200c is merely an example, and the pads, signal lines, and insulation layers are not limited to the configuration shown in Figure 2. The number of wiring layers constituting the signal processing IC 100 is also not limited to the configuration shown in Figure 2.

[0048] Furthermore, in this embodiment, an example was described in which the shield layer 210 is provided on the wiring layer 200a that is closest to the conductor portion 141 among the multiple wiring layers 200a, 200b, and 200c. However, the wiring layer on which the shield layer 210 is provided may be wiring layer 200b, or other wiring layers such as wiring layer 200b. The shield layer 210 may be provided on a wiring layer other than the wiring layer 200a that is closest to the conductor portion 141, as long as it is positioned opposite the conductor portion 141 and a slit 212 is provided opposite the conductor portion 141.

[0049] As described above, according to this embodiment, the signal processing IC 100 has a shield layer 210 made of a conductive material at a position facing the conductor portion 141. Furthermore, the shield layer 210 includes a slit 212 at a position overlapping with the conductor portion 141 in a plan view. The slit 212 may be made of an insulator that is not made of a conductive material. By providing such a slit 212, eddy currents generated in the shield layer 210 can be suppressed. Furthermore, by providing the slit 212 at a position overlapping with the conductor portion 141, the shield layer 210 can be made less susceptible to the effects of thermal stress caused by heat generated in the conductor portion 141 when current flows through it. Therefore, according to this embodiment, the effects of magnetic fields, eddy currents, and thermal stress that may occur when current flows through the conductor portion 141, which may occur by shortening the distance between the signal processing IC 100 and the lead frame 140 (conductor portion 141), can be suppressed.

[0050] Furthermore, by arranging the side wall portion 155, which is a step in the holding portion 151 and is made of conductive material, around the side of the signal processing IC 100, the shielding performance of the signal processing IC 100 can be further improved.

[0051] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0052] It should be noted that the execution order of operations, procedures, steps, and stages in the apparatus, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before," "prior to," etc., and that these can be implemented in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," "next," etc. for convenience, it does not mean that it is essential to perform the operations in that order. [Explanation of Symbols]

[0053] 10 Current Sensor 20a, 20b Magnetoelectric conversion element 22a, 22b, 108 wire 23a, 23b pads 100 Signal Processing ICs 130 Sealing part 140 Lead Frames 141 Conductor section 142 Terminal section Terminals 142a and 142b 150 Lead Frames 151 Holding part 152 Terminal section 152a terminal 154 Holding part 155 Side wall part 200a, 200b, 200c wiring layer 204a, 204b via 206 signal line 210 Shield layer 212 Slits 214 Insulating layer 230 Insulating layer

Claims

1. At least one magnetoelectric conversion element, A first lead frame includes a first terminal portion and a conductor portion connected to the first terminal portion, through which a measurement current measured by the at least one magnetoelectric conversion element flows via the first terminal portion and the conductor portion. A signal processing IC having at least one wiring layer and processing the signal output from the at least one magnetoelectric conversion element, The system comprises the at least one magnetoelectric conversion element, the conductor portion, and the sealing portion for sealing the signal processing IC, The at least one wiring layer includes a shielding layer containing a conductive material at a position facing the conductor portion. The shielding layer includes a slit in a position that overlaps with the conductor portion in a plan view, and is a current sensor.

2. The current sensor according to claim 1, wherein the magnetoelectric conversion element is arranged on a first wiring layer of the at least one wiring layer, or is integrated with the signal processing IC.

3. The current sensor according to claim 1, wherein the magnetoelectric conversion element is arranged on a first wiring layer among the at least one wiring layer.

4. The current sensor according to claim 3, wherein the at least one magnetoelectric conversion element is electrically connected to the signal processing IC via a plurality of wires, and each of the plurality of wires is electrically connected to the signal processing IC without crossing the first lead frame in a plan view.

5. The current sensor according to claim 1, wherein the first wiring layer among the at least one wiring layer includes the shielding layer.

6. The current sensor according to claim 5, wherein the first wiring layer is provided on the surface of the signal processing IC facing the conductor portion.

7. The current sensor according to claim 6, wherein the shielding layer is not provided in the portion where the at least one magnetoelectric conversion element is installed.

8. The current sensor according to any one of claims 1 to 7, wherein the shield layer is grounded.

9. The signal processing IC further comprises a holding portion that holds the surface opposite to the surface facing the conductor portion, The holding portion includes a holding portion for holding the signal processing IC and a side wall portion made of a conductive material that rises from the holding portion toward the conductor portion. The current sensor according to any one of claims 1 to 7, wherein the side wall portion overlaps with the signal processing IC when viewed from a direction along the surface of the holding portion.

10. The system further comprises a second lead frame electrically connected to the aforementioned signal processing IC, The current sensor according to claim 9, wherein the holding portion is part of the second lead frame.

11. The current sensor according to any one of claims 1 to 7, wherein the slit is made of an insulator.

Images