Current sensor

Abstract

The current sensor may comprise: at least one magnetoelectric conversion element having a magnetic surface and detecting a magnetic field in a direction along the magnetic surface; a current conductor having a first body portion positioned opposite at least a part of the magnetic surface and through which a measurement current that generates a magnetic field detected by the at least one magnetoelectric conversion element flows; a signal processing IC that processes the signal output from the at least one magnetoelectric conversion element; a support portion that supports a second surface of the signal processing IC opposite to the first surface facing the current conductor; and a sealing portion that seals the at least one magnetoelectric conversion element, the first body portion of the current conductor, the signal processing IC, and the support portion with a molding resin. At least the molding resin may be present throughout the space between the signal processing IC and the current conductor.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a coreless current sensor including a magnetoresistive element that detects a transverse magnetic field. Patent Document 2 discloses a current sensor in which two lead frames are stacked in the thickness direction to bring the magnetosensitive surface of the magnetic sensor closer to the current conductor. [Prior Art Documents] [Patent Documents] [Patent Document 1] International Publication No. 2021 / 039264 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-36237

Summary of the Invention

Problems to be Solved by the Invention

[0003] In a current sensor including a magnetoelectric conversion element that detects a magnetic field in a direction along the magnetosensitive surface, it is desired to ensure a higher electromagnetic conversion coefficient and improve current detection accuracy.

Means for Solving the Problems

[0004] A current sensor according to one aspect of the present invention may include at least one magnetoelectric conversion element having a magnetic surface and detecting a magnetic field in a direction along the magnetic surface. The current sensor may include a current conductor having a first body portion positioned opposite at least a portion of the magnetic surface and through which a measurement current that generates a magnetic field detected by the at least one magnetoelectric conversion element flows. The current sensor may include a signal processing IC that processes the signal output from the at least one magnetoelectric conversion element. The current sensor may include a support portion that supports a second surface of the signal processing IC opposite to the first surface facing the current conductor. The current sensor may include a sealing portion that seals the at least one magnetoelectric conversion element, the first body portion of the current conductor, the signal processing IC, and the support portion with a molding resin. At least the molding resin may be present throughout the space between the signal processing IC and the current conductor.

[0005] In the current sensor described above, the current conductor may be a first lead frame.

[0006] In any of the current sensors, the support portion and the first body portion may be located at different positions in a first direction intersecting the magnetic surface, and may be arranged to overlap at least partially when viewed from the first direction.

[0007] In any of the current sensors, the current conductor may further include a first terminal portion connected to the first body portion and exposed outside the sealing portion. The current sensor may further include a second lead frame which includes a second terminal portion located opposite the first terminal portion with respect to the signal processing IC when viewed from a first direction intersecting the magnetic surface, and which is electrically connected to the signal processing IC.

[0008] In any of the current sensors, the entire surface of the first body portion, excluding the portion connected to the first terminal portion, may be covered solely with the molded resin.

[0009] In any of the current sensors, an insulating sheet may be further provided, which is arranged over the entire area between the signal processing IC and the first body portion.

[0010] In any of the current sensors, the molding resin may be made of epoxy resin or a composite material containing epoxy resin.

[0011] In any of the current sensors, the epoxy resin may be a polyaromatic ring resin.

[0012] In any of the current sensors, the molding resin includes epoxy resin and an inorganic filler, and the distance between the current conductor and the magnetic surface may be greater than or equal to the maximum diameter of the filler.

[0013] In any of the current sensors, the magnetosensitive surface of the at least one magnetoelectric conversion element may be covered by the current conductor when viewed from a first direction intersecting the magnetosensitive surface.

[0014] In any of the current sensors, the first terminal portion may have a pair of terminals. The first body portion may include a first portion connected to one of the pair of terminals and extending in a second direction along the magnetic surface, a second portion connected to the other of the pair of terminals and extending in the second direction, and a connecting portion extending in a third direction along the magnetic surface and intersecting the second direction, connecting the first portion and the second portion.

[0015] In any of the current sensors, the at least one magnetoelectric conversion element may include a first magnetoelectric conversion element located in a position overlapping with the first portion when viewed from a first direction intersecting the magnetosensitive surface, and a second magnetoelectric conversion element located in a position overlapping with the second portion.

[0016] In any of the current sensors, when viewed from a first direction intersecting the magnetic sensing surface, if W (mm) is the width in the direction intersecting the extending direction of the first portion of the first body that coincides with the center of the first magnetic sensing surface of the first magnetoelectric conversion element, the center of the first magnetic sensing surface of the first magnetoelectric conversion element may be in a range of 0 mm or more and 0.1W + 0.3 mm or less from the end of the first portion of the first body that faces the second portion, when viewed from the first direction.

[0017] In any of the current sensors, if the area of ​​the first portion where the side facing the second portion is not connected to the connecting portion is defined as the first rectangular region, and the area of ​​the second portion where the side facing the first portion is not connected to the connecting portion is defined as the second rectangular region, then when viewed from the first direction, the first magnetoelectric conversion element may be located in a position overlapping with the first rectangular region, and the second magnetoelectric conversion element may be located in a position overlapping with the second rectangular region.

[0018] In any of the current sensors, the at least one magnetoelectric conversion element may include a first magnetoelectric conversion element positioned overlapping the first portion when viewed from a first direction intersecting the magnetosensitive surface, and a second magnetoelectric conversion element positioned overlapping the second portion when viewed from the first direction. When viewed from the first direction, the width of the first portion of the first magnetoelectric conversion element that overlaps the first magnetosensitive surface and intersects the direction in which the measured current flows may be equal to the width of the second portion of the second magnetoelectric conversion element that overlaps the second magnetosensitive surface and intersects the direction in which the measured current flows when viewed from the first direction. When viewed from the first direction, the distance from the edge of the first portion to the center of the first magnetosensitive surface may be equal to the distance from the edge of the second portion to the center of the second magnetosensitive surface. The signal processing IC may measure the measured current based on the difference signal between the signal output from the first magnetoelectric conversion element and the signal output from the second magnetoelectric conversion element.

[0019] In any of the current sensors, the first magnetoelectric conversion element may be electrically connected to the signal processing IC via a plurality of first wires. The second magnetoelectric conversion element may be electrically connected to the signal processing IC via a plurality of second wires. The plurality of first wires and the plurality of second wires may be of the same shape.

[0020] In any of the current sensors, the plurality of first wires may extend along the first magnetosensitive surface at a first portion that overlaps the first magnetosensitive surface as viewed from the first direction, and in a direction intersecting the direction in which the measured current flows at the first portion. The plurality of second wires may extend along the second magnetosensitive surface at a second portion that overlaps the second magnetosensitive surface as viewed from the first direction, and in a direction intersecting the direction in which the measured current flows at the second portion.

[0021] In any of the current sensors, the support portion may be a part of the second lead frame.

[0022] In any of the current sensors, as viewed from a first direction intersecting the magnetosensitive surface, the magnetosensitive surface may overlap the signal processing IC.

[0023] In any of the current sensors, the at least one magnetoelectric conversion element may be built in a chip constituting the signal processing IC.

[0024] In any of the current sensors, the at least one magnetoelectric conversion element and the signal processing IC may be constituted by separate chips and may be electrically connected via a plurality of wires.

[0025] In any of the current sensors, the support portion may be separate from the second lead frame.

[0026] In any of the above current sensors, the signal processing IC and the at least one magnetoelectric conversion element may be formed as separate chips and electrically connected via a plurality of wires. The at least one magnetoelectric conversion element may be arranged to face the signal processing IC in a direction along the magnetosensitive surface when viewed from a first direction intersecting the magnetosensitive surface. The distance between the magnetosensitive surface and the current conductor may be shorter than the distance between the first surface of the signal processing IC and the current conductor.

[0027] In any of the above current sensors, of the at least one magnetoelectric conversion element, the surface on the side opposite to the magnetosensitive surface may be closer to the current conductor than the surface on the side opposite to the first surface of the signal processing IC.

[0028] In any of the above current sensors, bonding balls may be present on the side of the signal processing IC among the plurality of wires.

[0029] In any of the above current sensors, the plurality of wires may not intersect the end face of the first body portion when viewed from a first direction intersecting the magnetosensitive surface.

[0030] The sealing portion may have a first surface on the side of the first surface of the signal processing IC. The current conductor may have a first conductor portion and a second conductor portion located farther from the first surface of the sealing portion in a first direction intersecting the magnetosensitive surface than the first conductor portion. When viewed from a direction along the magnetosensitive surface, the magnetosensitive surface may be located between a second surface on the side opposite to the first surface of the sealing portion facing the first conductor portion and a second surface on the side opposite to the first surface of the sealing portion facing the second conductor portion.

[0031] Note that the above summary of the invention does not list all the features of the present invention. Also, sub-combinations of these feature groups may also be inventions.

Brief Description of the Drawings

[0032] [Figure 1A]This is a schematic plan view of the current sensor according to the first embodiment, as seen from the ceiling side. [Figure 1B] Figure 1A is a cross-sectional view of the current sensor shown along line AA. [Figure 1C] This is a cross-sectional view of a current sensor according to a modified example of the first embodiment, shown along line AA. [Figure 2] This diagram shows the positional relationship between the first and second parts and the magnetoelectric conversion element when viewed from the negative side in the y-axis direction. [Figure 3] This figure shows a graph of simulation results illustrating the relationship between the distance hb from the end of the second part on the first part side to the center of the magnetosensitive surface of the magnetoelectric conversion element and the magnitude of the lateral magnetic field at that distance hb, when the width Wb of the second part is 2 mm and the distance kb between the second part and the magnetosensitive surface of the magnetoelectric conversion element is 0.1 mm. [Figure 4] This figure shows the relationship between the distance hb from the edge of the second part to the center of the magnetosensitive surface of the magnetoelectric conversion element, corresponding to the width Wb of the second part, and the rate of variation of the electromagnetic conversion coefficient, when the frequency of the measured current is 10 MHz and the distance kb is 0.1 mm. [Figure 5] This figure shows the relationship between the position where sensitivity is constant (distance hb) and the width Wb of the second part. [Figure 6A] This is a schematic plan view of the current sensor according to the second embodiment, as seen from the ceiling side. [Figure 6B] Figure 6A is a cross-sectional view of the current sensor shown along line AA. [Figure 7A] This is a schematic plan view of the current sensor according to the third embodiment, as seen from the ceiling side (z-axis direction). [Figure 7B] Figure 7A is a cross-sectional view of the current sensor shown along line AA. [Figure 8A] This is a schematic plan view of the current sensor according to the fourth embodiment, as seen from the ceiling side (z-axis direction). [Figure 8B] Figure 8A is a cross-sectional view of the current sensor shown along line AA. [Figure 9] Figure 8A shows an enlarged view of the magnetoelectric conversion element and signal processing IC portion of the current sensor, viewed from the negative direction of the y-axis. [Figure 10A]This is a schematic plan view of a current sensor according to a modified example of the fourth embodiment, as seen from the ceiling side (z-axis direction). [Figure 10B] Figure 10A is a cross-sectional view of the current sensor shown along line AA. [Figure 11A] This is a schematic plan view of the current sensor 10 according to the fifth embodiment, as seen from the ceiling side. [Figure 11B] Figure 11A is a cross-sectional view of the current sensor shown along line AA. [Figure 12] This figure shows the positional relationship between the signal processing IC and the magnetoelectric conversion element as viewed from the negative side in the y-axis direction in the fifth embodiment. [Figure 13A] This is a schematic plan view of the current sensor according to the sixth embodiment, as seen from the ceiling side. [Figure 13B] Figure 13A is a cross-sectional view of the current sensor along line AA. [Figure 14A] This is a schematic plan view of the current sensor according to the seventh embodiment, as seen from the ceiling side (z-axis direction). [Figure 14B] Figure 14A is a cross-sectional view of the current sensor along line AA. [Figure 15] This is a magnified view of a signal processing IC and a magnetoelectric conversion element. [Modes for carrying out the invention]

[0033] 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.

[0034] Figures 1A and 1B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the first embodiment. Figure 1A is a schematic plan view of the current sensor 10 according to the first embodiment, as seen from the top side (z-axis direction). Figure 1B is a cross-sectional view of the current sensor 10 shown in Figure 1A, along line AA.

[0035] In Figure 1A, the coordinate system is defined as follows: the x-axis is parallel to the plane of the paper and runs from bottom to top; the y-axis is parallel to the plane of the paper and runs from right to left; and the z-axis is perpendicular to the plane of the paper and runs from back to front. Any one of the x, y, or z axes is perpendicular to the other axes.

[0036] The current sensor 10 comprises a signal processing IC 100, a magnetoelectric conversion element 20a, a magnetoelectric conversion element 20b, a lead frame 140 which is a current conductor through which the measured current flows, a lead frame 150 on the signal terminal side, and a sealing part 130.

[0037] The lead frame 140 includes a body portion 141 and a terminal portion 142. The terminal portion 142 includes a pair of terminals 142a and 142b. The body portion 141 is sealed within the sealing portion 130. The body portion 141 is positioned opposite the magnetosensitive surface 21a of the magnetoelectric conversion element 20a and the magnetosensitive surface 21b of the magnetoelectric conversion element 20b, respectively. A measurement current flows through the current conductor 141, which generates a magnetic field detected by the magnetoelectric conversion elements 20a and 20b. The magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b are covered by the body portion 141 when viewed from the z-axis direction.

[0038] The body portion 141 includes a first portion 1414 connected to terminal 142a and extending in the y-axis direction, which is along the magnetic surface 21a of the magnetoelectric conversion element 20a; a second portion 1415 connected to terminal 142b and extending in the y-axis direction; and a connecting portion 1416 extending in the x-axis direction, which is along the magnetic surface 21a (21b) and intersects with the y-axis direction, and connecting the first portion 1414 and the second portion 1415. The first portion 1414 is positioned facing the magnetic surface 21a of the magnetoelectric conversion element 20a in the z-axis direction, which is in the direction intersects with the magnetic surface 21a of the magnetoelectric conversion element 20a. It is sufficient that at least a portion of the magnetic surface 21a of the magnetoelectric conversion element 20a is positioned facing the first portion 1414. The second portion 1415 is positioned facing the magnetic surface 21b of the magnetoelectric conversion element 20b in the z-axis direction. It is sufficient that at least a portion of the magnetosensitive surface 21b of the magnetoelectric conversion element 20b is positioned facing the second portion 1415.

[0039] Viewed from the z-axis direction, the width Wa in the first portion 1414 that overlaps with the magnetosensitive surface 21a of the magnetoelectric conversion element 20a, along the magnetosensitive surface 21a and intersecting the direction in which the measured current flows, i.e., the width in the x-axis direction, is equal to the width Wb in the second portion 1415 that overlaps with the magnetosensitive surface 21b of the magnetoelectric conversion element 20b, along the magnetosensitive surface 21b and intersecting the direction in which the measured current flows, i.e., the width in the x-axis direction, as viewed from the z-axis direction. Furthermore, as viewed from the z-axis direction, the distance ha from the end of the first portion 1414 on the second portion 1415 side to the center of the magnetosensitive surface 21a is equal to the distance hb from the end of the second portion 1415 on the first portion 1414 side to the center of the magnetosensitive surface 21b.

[0040] The pair of terminals 142a and 142b are physically integrated with the body portion 141 and are exposed outside the sealing portion 130. A measurement current is input from one of the pair of terminals 142a and 142b, and the measurement current is output from the other of the pair of terminals 142a and 142b via the body portion 141. The lead frame 140 is an example of a first lead frame. The conductor portion 141 is an example of a first conductor portion.

[0041] The lead frame 140 does not need to be manufactured using a form in which multiple body portions 141 and terminal portions 142 are connected together; it may be manufactured using individual metal parts. Furthermore, in the current sensor 10, another current conductor through which the measured current flows may be used instead of the lead frame 140.

[0042] The lead frame 150 includes an IC suspension portion 151 and a terminal portion 152. The terminal portion 152 includes a plurality of terminals 152a. The IC suspension portion 151 is sealed within the sealing portion 130 and supports the signal processing IC 100. The plurality of terminals 152a are physically integral with the IC suspension portion 151 and are exposed outside the sealing portion 130. The lead frame 150 is an example of a second lead frame.

[0043] The lead frames 140 and 150 may be made of a conductive material mainly composed of copper. The x-axis is the direction along the planes of the lead frames 140 and 150, and is the direction in which the multiple terminals 152a are arranged. The y-axis is the direction along the planes of the lead frames 140 and 150, and is also the direction intersecting the x-axis. In a plan view, the y-axis is also the direction in which the multiple terminals 152a and the pair of terminals 142a and 142b extend. The z-axis is the direction intersecting the planes of the lead frames 140 and 150, and is also the direction intersecting the circuit plane of the signal processing IC 100 or the magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b, and is also the thickness direction of the sealing portion 130.

[0044] The pair of terminals 142a and 142b and the multiple terminals 152a are arranged facing each other via the signal processing IC 100 in a direction (y-axis direction) that intersects with the thickness direction (z-axis direction) of the signal processing IC 100. The pair of terminals 142a and 142b are exposed from the side surface 130a of the sealing portion 130. The multiple terminals 152a are exposed from the side surface 130b of the sealing portion 130 opposite to the side surface 130a. By having the pair of terminals 142a and 142b and the multiple terminals 152a protrude from the opposing side surfaces 130a and 130b, the creepage distance between the pair of terminals 142a and 142b and the multiple terminals 152a can be increased, thereby suppressing creepage discharge from the pair of terminals 142a and 142b to the multiple terminals 152a.

[0045] As shown in Figure 1B, the pair of terminals 142a, 142b and the multiple terminals 152a may protrude outward from different heights in the thickness direction of the sealing portion 130 on the opposing sides 130a and 130b of the sealing portion 130. At least a portion of the pair of terminals 142a, 142b and the multiple terminals 152a may be exposed from the bottom surface 130f of the sealing portion 130.

[0046] The height in the thickness direction (z-axis direction) of the sealing portion 130 on the same side surface 1521 as the side 100a of the signal processing IC 100 for the multiple terminals 152a at the position where it intersects with the side surface 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 surface 1422 as the opposite side of the side 100a of the signal processing IC 100 for the pair of terminals 142a and 142b at the position where it intersects with the side surface 130a of the sealing portion 130, can be the same.

[0047] By arranging the lead frame 140 and lead frame 150 in this positional relationship, the lead frame 150 and lead frame 140 can be stacked in the thickness direction (z-axis direction) during the manufacturing of the current sensor 10, thereby suppressing misalignment of the positional relationship between the lead frame 150 and lead frame 140 in the thickness direction. As a result, the body portion 141 can be brought closer to the magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b with high precision, thereby increasing the magnetic sensitivity of the magnetoelectric conversion elements 20a and 20b and improving the reliability of the current sensor 10.

[0048] Furthermore, the height of the surface 1521 of the multiple terminals 152a at the position where it intersects with the side surface 130b of the sealing portion 130 in the thickness direction (z-axis direction) of the sealing portion 130 may be located lower than the height of the surface 1422 of the pair of terminals 142a and 142b at the position where it intersects with the side surface 130a of the sealing portion 130 in the thickness direction (z-axis direction) of the sealing portion 130.

[0049] 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.

[0050] The IC suspension portion 151 includes a support portion 154 that supports the signal processing IC 100. The support portion 154 supports the surface 100a facing the body portion 141 of the signal processing IC 100 and the opposite surface 100b. The support portion 154 and the body portion 141 are located at different positions in the z-axis direction and are arranged to overlap when viewed from the z-axis direction. The lead frame 150 may have a stepped portion 155 in which the support portion 154 is recessed in the thickness direction (z-axis direction) away from the body portion 141 (towards the bottom surface of the sealing portion 130). The signal processing IC 100 may be fixed to the surface 154a of the support portion 154 via an adhesive layer 160. The adhesive layer 160 may be a die attach film.

[0051] The magnetoelectric conversion elements 20a and 20b detect a magnetic field in any one axis direction on the xy plane, i.e., a transverse magnetic field. The magnetoelectric conversion elements 20a and 20b may be magnetoresistive elements such as giant magnetoresistance (GMR) elements, semiconductor magnetoresistance (SMR) elements, anisotropic magnetoresistance (AMR) elements, or tunnel magnetoresistance (TMR) elements, or vertical Hall elements made of compounds such as InAs and GaAs or silicon (Si).

[0052] The magnetoelectric conversion elements 20a and 20b are built into the chip that constitutes the signal processing IC 100. In other words, the magnetoelectric conversion elements 20a and 20b and the signal processing IC 100 are all made up of the same chip. The magnetoelectric conversion elements 20a and 20b and the signal processing IC 100 are all made of silicon monolithic material and are made up of the same chip. In the first embodiment, an example is described in which the current sensor 10 has two magnetoelectric conversion elements 20a and 20b. However, the current sensor 10 only needs to have one or more magnetoelectric conversion elements.

[0053] The signal processing IC 100 is electrically connected to multiple terminals 152a via wire 108. Wire 108 may be made of a conductive material mainly composed of Au, Ag, Cu, or Al.

[0054] 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 measurement current flowing through the body portion 141 and outputs an output signal indicating the accurate current value via terminal 152a. The signal processing circuit measures the measurement current based on the difference signal between the output signal output from magnetoelectric conversion element 20a and the output signal output from magnetoelectric conversion element 20b. The signal processing circuit reduces noise components contained in the output signals of magnetoelectric conversion element 20a and magnetoelectric conversion element 20b based on the difference signal between the output signal of magnetoelectric conversion element 20a and the output signal of magnetoelectric conversion element 20b, amplifies the output signals of magnetoelectric conversion element 20a and magnetoelectric conversion element 20b with reduced noise components, calculates the current value of the measured current based on the amplified output signal, and outputs an output signal indicating the current value.

[0055] The sealing portion 130 seals the magnetoelectric conversion elements 20a, 20b, the body portion 141, the IC suspension portion 151, the signal processing IC 100, and the wire 108 with a molding resin. The molding resin is, for example, an epoxy-based thermosetting resin (epoxy resin) with silica added, and may be molded into a semiconductor package using a transfer mold. The molding resin may also be a composite material containing epoxy resin, for example, a composite material containing epoxy resin and an inorganic filler. The epoxy resin may be a polyaromatic ring resin.

[0056] At least a layer of molded resin is present throughout the space between the signal processing IC 100 and the body portion 141. The entire surface of the body portion 141, excluding the connection portion with the terminal portion 142, is covered with molded resin. The body portion 141 is electrically insulated from the magnetoelectric conversion elements 20a, 20b and the signal processing IC 100 by the sealing portion 130, and there are no interfaces between the components.

[0057] Here, the heat generated by the current flowing through the body portion 141 makes it easy for the temperature around the body portion 141 to fluctuate wildly. Therefore, thermal stress is likely to occur around the body portion 141. This thermal stress may cause delamination between the body portion 141 and the molded resin. If there is an interface between the body portion 141 and the signal processing IC 100, delamination tends to propagate along that interface, causing a gap to form between the body portion 141 and the signal processing IC 100. Such a gap can compromise the withstand voltage and potentially lead to failure. On the other hand, according to the current sensor 10 of the first embodiment, as described above, at least molded resin is present throughout the entire space between the signal processing IC 100 and the body portion 141, so there is no interface between the body portion 141 and the signal processing IC 100. Therefore, discharge along the interface does not occur under operating conditions. Furthermore, by composing the molded resin with epoxy resin or a composite material containing epoxy resin, the withstand voltage can be increased compared to other polymer materials. Therefore, the distance between the body portion 141 and the signal processing IC 100 can be shortened, bringing the magnetic sensing surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b built into the signal processing IC 100 closer to the body portion 141, thereby ensuring a high electromagnetic conversion coefficient and improving current detection accuracy.

[0058] On the other hand, if the stress that the magnetoelectric conversion elements 20a and 20b receive from the molding resin changes, the sensitivity of the magnetoelectric conversion elements may fluctuate, and even if a high electromagnetic conversion coefficient is achieved, the accuracy may decrease. Here, the water absorption rate can be reduced by using an epoxy resin composed of polyaromatic ring resin, or a composite material of a molding resin with an inorganic filler that is highly filled with inorganic fillers (80% or more). In that case, the degree of expansion in a high-humidity environment can be reduced, and fluctuations in the stress applied to the magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b can be suppressed, and as a result, fluctuations in sensitivity can be suppressed.

[0059] Here, it is desirable to ensure that the distance between the body portion 141 and the magnetosensitive surfaces 21a and 21b is at least equal to the maximum diameter of the filler. This prevents the mold resin from not filling the space between the body portion 141 and the magnetoelectric conversion elements 20a and 20b, and ensures withstand voltage.

[0060] Figure 1C is a cross-sectional view of the current sensor 10 according to a modified example of the first embodiment, shown along line AA. The current sensor 10 according to the modified example of the first embodiment differs from the current sensor 10 of the first embodiment in that it further includes an insulating sheet 170 that is placed over the entire area between the signal processing IC 100 and the body portion 141. The insulating sheet 170 is made of an insulating material and may be placed on the surface 1412 of the body portion 141 that faces the signal processing IC 100. By providing the insulating sheet 170, insulation between the body portion 141 and the signal processing IC 100 can be more reliably ensured.

[0061] Figure 2 shows the positional relationship between the first part 1414 and the magnetoelectric conversion element 20a, and the positional relationship between the second part 1415 and the magnetoelectric conversion element 20b, when viewed from the negative side in the y-axis direction. Figure 3 shows a graph of simulation results showing the relationship between the distance hb from the end 1415b of the second part 1415 on the first part 1414 side to the center of the magnetoelectric conversion element 20b's magnetoelectric conversion element 20b and the magnitude of the magnetic field (magnetic flux density) in the lateral direction (x-axis direction) at that distance hb, when the width Wb in the direction intersecting the direction in which the measured current flows through the second part 1415 is 2 mm, and the distance kb between the body part 141 (second part 1415) and the magnetosensitive surface 21b of the magnetoelectric conversion element 20b is 0.1 mm.

[0062] The region where distance hb is negative is the region where the center of the magnetic surface 21b does not overlap with the second part 1415 when viewed from the z-axis direction, and the region where distance hb is positive is the region where the center of the magnetic surface 21b overlaps with the second part 1415 when viewed from the z-axis direction. As shown in Figure 3, the magnetic field (magnetic flux density) is large and the electromagnetic conversion coefficient is high at the position where the current conductor 141 and the magnetic surface 21b overlap when viewed from the z-axis direction.

[0063] When the measured current flowing through the body portion 141 changes drastically, that is, when the frequency of the measured current is high, the electromagnetic conversion coefficient generally changes due to the skin effect of the body portion 141. In particular, when detecting a transverse magnetic field, the change in the electromagnetic conversion coefficient is larger than when detecting a longitudinal magnetic field. Here, since the first portion 1414 and the second portion 1415, in which the current conductor extends in the y-axis direction, are connected by the connecting portion 1416, the direction of current flow is opposite in the first portion 1414 and the second portion 1415. In this case, even if it is DC, the current density is higher on the second portion 1415 side of the first portion 1414. Similarly, the current density is higher on the first portion 1414 side of the second portion 1415. That is, in the body portion 141, a bias in current density occurs such that the current density is higher in the portion where the first portion 1414 and the second portion 1415 are close together and facing each other. By creating a bias in the DC current density, the rate of change in the bias in current density when a rapidly changing current is applied can be suppressed. In particular, the current density is high in the portion of the surface where the first part 1414 and the second part 1415 are arranged facing each other, and which is not connected to the connecting part 1416.

[0064] Figure 4 shows the relationship between the distance hb from the end 1415b of the second part 1415 to the center of the magnetosensitive surface 21b of the magnetoelectric conversion element 20b, and the rate of change of the electromagnetic conversion coefficient, when the frequency of the measured current is 10 MHz and the distance kb is 0.1 mm, depending on the width Wb of the second part 1415. Although the magnitude of the rate of change of the electromagnetic conversion coefficient differs depending on the width Wb of the second part 1415, for any width Wb, when viewed from the z-axis direction, the rate of change of the electromagnetic conversion coefficient is large when the center of the magnetosensitive surface 21b of the magnetoelectric conversion element 20b is located near the end 1415b of the body part 141, and when viewed from the z-axis direction, the rate of change of the electromagnetic conversion coefficient is small when the magnetosensitive surface 21b of the magnetoelectric conversion element 20b overlaps with the body part 141.

[0065] As shown in Figure 4, when viewed from the z-axis direction, if the magnetosensitive surface 21b of the magnetoelectric conversion element 20b overlaps with the body portion 141, the rate of change of the electromagnetic conversion coefficient decreases and turns negative as the center of the magnetosensitive surface 21b of the magnetoelectric conversion element 20b moves away from the edge 1415b of the body portion 141. When the rate of change of the electromagnetic conversion coefficient becomes negative, the magnetic sensitivity decreases. The position where the rate of change of the electromagnetic conversion coefficient changes from positive to negative is the position where the rate of change of the electromagnetic conversion coefficient becomes zero, and this position is where no sensitivity fluctuation occurs due to the skin effect of the body portion 141.

[0066] Figure 5 shows the relationship between the position where sensitivity is constant (distance hb) and the width Wb of the second section 1415. From this relationship, the position where sensitivity is constant can be approximated as hb = 0.1 × Wb + 0.15 [mm]. In other words, when the distance hb is 0.1 × Wb + 0.15 [mm], the sensitivity variation due to the skin effect of the body section 141 is eliminated.

[0067] Furthermore, if the distance hb is less than 0.1 × Wb + 0.15 [mm], that is, if the center of the magnetic surface 21b is closer to the edge 1415b of the body portion 141 than 0.1 × Wb + 0.15 [mm], the rate of sensitivity variation due to the skin effect becomes larger, as described above. However, this region is the area where the body portion 141 and the IC tab, i.e., the support portion 154, overlap when viewed from the z-axis direction, and the sensitivity variation due to the skin effect can be suppressed by the eddy currents generated in the support portion 154.

[0068] Therefore, if the distance hb is 0.1 × Wb + 0.15 [mm] or less, sensitivity fluctuations due to the skin effect of the body portion 141 can be suppressed. However, it is preferable to consider errors during the manufacturing stage of the current sensor 10. That is, even if the distance hb becomes 0.15 [mm] longer than 0.1 × Wb + 0.15 [mm], considering positional variations in die bonding or positional variations in the body portion 141, it will not lead to a significant deterioration of characteristics.

[0069] Therefore, it is preferable that the center of the magnetosensitive surface 21a of the magnetoelectric conversion element 20a is located in a range of 0 mm or more and 0.1 Wa + 0.3 mm or less from the end of the first part 1414 on the second part 1415 side, when viewed from the z-axis direction. Also, it is preferable that the center of the magnetosensitive surface 21b of the magnetoelectric conversion element 20b is located in a range of 0 mm or more and 0.1 Wb + 0.3 mm or less from the end of the second part 1415 on the first part 1414 side, when viewed from the z-axis direction.

[0070] Furthermore, as described above, since the current density is high in the portion of the surface where the first portion 1414 and the second portion 1415 are arranged facing each other that is not connected to the connecting portion 1416, it is preferable that the magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b are located in a position that overlaps with the first rectangular region 1414a, where the surface of the first portion 1414 facing the second portion 1415 is not connected to the connecting portion 1416, and in a position that overlaps with the second rectangular region 1415a, where the surface of the second portion 1415 facing the first portion 1414 is not connected to the connecting portion 1416, as shown in Figure 1A.

[0071] Furthermore, in the case of a current sensor as described in Patent Document 1, the surface of the signal processing IC on which the magnetic sensor is provided is the surface opposite to the surface facing the current conductor. Therefore, the distance between the magnetic sensing surface of the magnetic sensor and the current conductor is large, and the magnetic sensor cannot effectively detect the magnetic field. On the other hand, in the case of the current sensor 10 according to the first embodiment and its modified form, the distance between the magnetic sensing surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b and the body portion 141 can be shortened, and the magnetoelectric conversion elements 20a and 20b can effectively detect the magnetic field. In other words, the electromagnetic conversion coefficient can be increased, and the signal against noise can be made stronger.

[0072] According to the current sensor described in Patent Document 2, the distance between the magnetosensitive surface of the magnetoelectric conversion element and the current conductor can be shortened by using two lead frames. However, since the magnetoelectric conversion element is placed inside the opening of the current conductor, and the current path flowing through the current conductor branches in two directions, the electromagnetic conversion coefficient cannot be effectively increased. Furthermore, the loop formed by the wire connecting the magnetoelectric conversion element and the signal processing IC is large when viewed from the z-axis direction. In such a situation, since the magnetoelectric conversion element is placed inside the opening of the current conductor, a large component of magnetic flux density perpendicular to the loop formed by the wire enters, and when a time-varying measurement current flows through the current conductor, an induced electromotive force is generated in the wire. This degrades the frequency characteristics. On the other hand, according to the current sensor 10 of the first embodiment and its modified form, there is no wire connecting the signal processing IC 100 and the magnetoelectric conversion elements 20a and 20b, and no degradation of frequency characteristics due to the generation of induced electromotive force occurs.

[0073] Figures 6A and 6B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the second embodiment. Figure 6A is a schematic plan view of the current sensor 10 according to the second embodiment, viewed from the top side (z-axis direction). Figure 6B is a cross-sectional view of the current sensor 10 shown in Figure 6A, taken along line AA.

[0074] The current sensor 10 according to the second embodiment differs from the current sensor 10 according to the first embodiment in that the IC suspension portion 151 does not have a stepped portion 155, while the body portion 141 has a stepped portion 145. The body portion 141 has a first conductor portion 143 and a second conductor portion 144 located further away from the first conductor portion 143 in the z-axis direction from the surface 130e, which is the ceiling surface of the sealing portion 130. The stepped portion 145 connects the first conductor portion 143 and the second conductor portion 144. The second conductor portion 144 is recessed in the z-axis direction away from the first conductor portion 143 (towards the surface 130f, which is the bottom surface of the sealing portion 130) via the stepped portion 145. The stepped portion 145 may be formed by bending the body portion 141.

[0075] Because the body portion 141 has a stepped portion 145, the magnetosensitive surfaces 21a and 21b are located between the surface 143a of the first conductor portion 143 that faces the surface 130e of the sealing portion 130 and the surface 144a of the second conductor portion 144 that faces the surface 130e of the sealing portion 130 and the surface 144b that faces the opposite side of the surface 144a of the sealing portion 130. As a result, the measurement current 30 flows in a direction that includes a component in the thickness direction at the stepped portion 145, allowing the magnetoelectric conversion elements 20a and 20b to effectively detect the magnetic field in the x-axis direction (lateral direction) and increase the electromagnetic conversion coefficient.

[0076] Figures 7A and 7B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the third embodiment. Figure 7A is a schematic plan view of the current sensor 10 according to the third embodiment, viewed from the top side (z-axis direction). Figure 7B is a cross-sectional view of the current sensor 10 shown in Figure 7A, along line AA.

[0077] The current sensor 10 according to the third embodiment is the same as the current sensor 10 according to the second embodiment in that the body portion 141 has a stepped portion 145, but the method of processing the stepped portion 145 is different. In the third embodiment, the stepped portion 145 is formed by partially processing the body portion 141. In the third embodiment, the IC suspension portion 151 also has a stepped portion 155 formed by partially processing. The stepped portion 155 is formed such that the support portion 154 is recessed in the thickness direction (z-axis direction) away from the body portion 141 (towards the bottom surface of the sealing portion 130).

[0078] Even when the stepped portion 145 is formed by a half-through machining process, the magnetic sensing surfaces 21a and 21b are positioned between the surface 143b of the first conductor portion 143 and the surface 144b of the second conductor portion 144 when viewed from a direction along the magnetic sensing surfaces 21a and 21b (in the x-axis direction). As a result, the measured current 30 flows in a direction that includes a component in the thickness direction at the stepped portion 145, allowing the magnetoelectric conversion elements 20a and 20b to effectively detect the magnetic field in the x-axis direction (lateral direction) and increase the electromagnetic conversion coefficient.

[0079] Figures 8A and 8B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the fourth embodiment. Figure 8A is a schematic plan view of the current sensor 10 according to the fourth embodiment, viewed from the ceiling side (z-axis direction). Figure 8B is a cross-sectional view of the current sensor 10 shown in Figure 8A, along line AA. Figure 9 shows an enlarged view of the magnetoelectric conversion element 20a and signal processing IC 100 portion of the current sensor 10 shown in Figure 8A, viewed from the negative direction of the y-axis.

[0080] The current sensor 10 according to the fourth embodiment differs from the current sensor 10 according to the first to third embodiments, in that the magnetoelectric conversion elements 20a and 20b and the signal processing IC 100 are configured on separate chips.

[0081] 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 plurality of wires 22a and 22b are congruent, as shown in Figures 8A and 9. That is, the plurality of wires 22a and 22b are the same length and extend in the same direction. Wire 22a is an example of a first wire, and wire 22b is an example of a second wire.

[0082] The magnetic surface 21a and the multiple wires 22a are positioned to overlap the first portion 1414 when viewed from the z-axis direction, and the magnetic surface 21b and the multiple wires 22b are positioned to overlap the second portion 1415 when viewed from the z-axis direction. In other words, the multiple wires 22a and 22b do not intersect the end faces of the body portion 141 having the first portion 1414 and the second portion 1415 when viewed from the z-axis direction.

[0083] Multiple wires 22a extend along the magnetic surface 21a in a first portion 1414 that overlaps with the magnetic surface 21a when viewed from the z-axis direction, and in a direction intersecting the direction in which the measurement current flows through the first portion 1414. Multiple wires 22b extend along the magnetic surface 21b in a second portion 1415 that overlaps with the magnetic surface 21b when viewed from the z-axis direction, and in a direction intersecting the direction in which the measurement current flows through the second portion 1415.

[0084] By arranging wires 22a and 22b in this direction, the direction of wires 22a and 22b aligns with the direction of the magnetic field (magnetic flux density) generated when the measurement current flows through the first part 1414 and the second part 1415. This makes it difficult for the magnetic flux to enter the loop formed by wires 22a and 22b. As a result, even when a high-frequency measurement current flows through the body part 141, the induced electromotive force generated in wires 22a and 22b can be suppressed.

[0085] Figures 10A and 10B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to a modified example of the fourth embodiment. Figure 10A is a schematic plan view of the current sensor 10 according to a modified example of the fourth embodiment, viewed from the top surface side (z-axis direction). Figure 10B is a cross-sectional view of the current sensor 10 shown in Figure 10A, taken along line AA.

[0086] The current sensor 10 according to a modification of the fourth embodiment differs from the current sensor 10 according to the fourth embodiment, in that the support portion 154 is separate from the lead frame 150, and the support portion 154 is part of the lead frame 150. The support portion 154 may be made of the same conductive material as the lead frame 150, or it may be made of an insulating material such as polyimide.

[0087] By constructing the support portion 154 and the IC suspension portion 151 as separate components, and configuring the IC suspension portion 151 to hold the support portion 154, a stepped portion 155 can be provided between the IC suspension portion 151 and the support portion 154 without performing step processing on the lead frame 150. Since step processing is unnecessary, the accuracy of the height of the stepped portion 155 can be improved, and the accuracy of the distance between the body portion 141 and the magnetic sensing surfaces 21a and 21b can be improved. If there is variation in the distance between the body portion 141 and the magnetic sensing surfaces 21a and 21b, variations will occur in the withstand voltage characteristics and magnetic sensitivity. On the other hand, according to the current sensor 10 according to a modification of the fourth embodiment, by constructing the support portion 154 and the IC suspension portion 151 as separate components, the accuracy of the distance between the body portion 141 and the magnetic sensing surfaces 21a and 21b can be improved, so variations in withstand voltage characteristics and variations in magnetic sensitivity can be suppressed.

[0088] Figures 11A and 11B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the fifth embodiment. Figure 11A is a schematic plan view of the current sensor 10 according to the fifth embodiment, viewed from the ceiling side (z-axis direction). Figure 11B is a cross-sectional view of the current sensor 10 shown in Figure 11A, along line AA. Figure 12 shows the positional relationship between the signal processing IC 100 and the magnetoelectric conversion elements 20a and 20b, viewed from the negative side in the y-axis direction, in the fifth embodiment.

[0089] The current sensor 10 according to the fifth embodiment differs from the current sensor 10 according to the fourth embodiment and its modified version, in that the magnetoelectric conversion elements 20a and 20b are not arranged on the surface 100a of the signal processing IC 100, but rather are arranged adjacent to the signal processing IC 100 on the surface 154a of the support portion 154, similar to the signal processing IC 100.

[0090] In the fifth embodiment, 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 positioned opposite each other in a direction (x-axis direction) that intersects with respect to the direction of the measurement current flowing through the first portion 1414 and the second portion 1415, with the signal processing IC 100 in between, when viewed from the z-axis direction. The plurality of wires 22a and 22b extend in a direction (x-axis direction) that intersects with respect to the direction of the measurement current flowing through the first portion 1414 and the second portion 1415, when viewed from the z-axis direction.

[0091] This configuration allows for the formation of multiple loops of wires 22a and 22b along the direction of the magnetic field (magnetic flux density) generated by the measurement current flowing through the first section 1414 and the second section 1415. Furthermore, the size of the loops of wires 22a and 22b projected in the x-axis direction can be reduced compared to when the magnetoelectric conversion elements 20a and 20b are arranged on the surface 100a of the signal processing IC 100. As a result, magnetic flux is less likely to enter the loops formed by wires 22a and 22b. This suppresses the induced electromotive force generated in wires 22a and 22b even when a high-frequency measurement current flows through the body section 141. Even when the magnetoelectric conversion elements 20a and 20b are arranged in an optimal configuration that results in a high magnetic flux density entering them and minimal frequency fluctuations, the width of the signal processing IC 100 can be reduced.

[0092] Figures 13A and 13B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the sixth embodiment. Figure 13A is a schematic plan view of the current sensor 10 according to the sixth embodiment, viewed from the top side (z-axis direction). Figure 13B is a cross-sectional view of the current sensor 10 shown in Figure 13A, taken along line AA.

[0093] In the current sensor 10 according to the sixth embodiment, the positional relationship between the signal processing IC 100 and the magnetoelectric conversion elements 20a and 20b, as viewed from the z-axis direction, differs from that of the current sensor 10 according to the fifth embodiment. As viewed from the z-axis direction, the magnetoelectric conversion elements 20a and 20b are positioned adjacent to the side of the terminal portion 142 of the signal processing IC 100, without the IC 100 in between. Furthermore, the direction in which the wires 22a and 22b extend has a component in the direction of the measured current flowing through the first portion 1414 and the second portion 1415. Therefore, magnetic flux easily enters the loop formed by the wires 22a and 22b. Consequently, the induced electromotive force generated in the wires 22a and 22b makes it easier for noise to be included in the signals output from the magnetoelectric conversion elements 20a and 20b.

[0094] However, due to design or footprint constraints of the current sensor 10, the positional relationship between the signal processing IC 100 and the magnetoelectric conversion elements 20a and 20b may have to be arranged in this manner. In such arrangements, the magnetoelectric conversion elements 20a and 20b are positioned symmetrically with respect to the body portion 141, and the wires 22a and 22b are made congruent.

[0095] When viewed from the z-axis direction, if the width Wa of the first portion 1414 that overlaps with the magnetic surface 21a of the magnetoelectric conversion element 20a, along the direction intersecting the direction in which the measured current flows (x-axis direction), is equal to the width Wb of the second portion 1415 that overlaps with the magnetic surface 21b of the magnetoelectric conversion element 20b, along the direction intersecting the direction in which the measured current flows (X-axis direction), and when viewed from the z-axis direction, the distance ha from the end of the first portion 1414 to the center of the magnetic surface 21a and the distance hb from the end of the second portion 1415 to the center of the magnetic surface 21b are equal, then the magnetoelectric conversion elements 20a and 20b are in symmetrical positions.

[0096] With this configuration, when the signal processing IC 100 processes the signals output from magnetoelectric conversion element 20a and the signals output from magnetoelectric conversion element 20b, the difference between the signals output from magnetoelectric conversion element 20a and the signals output from magnetoelectric conversion element 20b can be taken to cancel out the noise generated by the induced electromotive force generated in wires 22a and 22b.

[0097] Figures 14A and 14B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the seventh embodiment. Figure 14A is a schematic plan view of the current sensor 10 according to the seventh embodiment, viewed from the top side (z-axis direction). Figure 14B is a cross-sectional view of the current sensor 10 shown in Figure 14A, along line AA. Figure 15 is an enlarged view of the signal processing IC 100 and magnetoelectric conversion elements 20a and 20b.

[0098] In the current sensor 10 according to the seventh embodiment, the IC suspension portion 151 has an opening 156, and the signal processing IC 100 is arranged inside the opening 156. A support portion 154 is arranged on the surface 151b opposite to the surface 151a of the IC suspension portion 151 that faces the body portion 141. The signal processing IC 100 is arranged on the surface 154a of the support portion 154 that faces the opening 156. The magnetoelectric conversion elements 20a and 20b are arranged adjacent to the side surface of the signal processing IC 100 on the terminal portion 142 side, and on the surface 151a of the IC suspension portion 151 that faces the body portion 141.

[0099] The support portion 154 is constructed separately from the lead frame 150, using materials such as polyimide tape, silicon, or a metal plate. In the seventh embodiment, the signal processing IC 100 and the magnetoelectric conversion elements 20a and 20b are configured on separate chips, and the signal processing IC 100 and the magnetoelectric conversion elements 20a and 20b are electrically connected via wires 22a and 22b.

[0100] Because the signal processing IC 100 is positioned within the opening 156, the distance k between the magnetic sensing surfaces 21a and 21b and the body portion 141 is shorter than the distance l between the surface 100a of the signal processing IC 100 and the body portion 141.

[0101] Wires 22a and 22b are connected to the surface 100a of the signal processing IC 100, and then to the magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b. Through this connection procedure, wires 22a and 22b extend upward in the z-axis direction from the surface 100a of the signal processing IC 100. Wires 22a and 22b may be connected to the surface 100a and magnetosensitive surfaces 21a and 21b of the signal processing IC 100 by ball bonding. When wires are connected by ball bonding, the wire near the ball is hard and difficult to bend due to the high density of crystal defects, while the 2nd bond area is joined at an angle to the pad and the wire is flexible. Therefore, by ball bonding to the surface 100a of the signal processing IC 100, cracking of the wires 22a and 22b can be suppressed while reducing the height of the rising portion of the wires 22a and 22b at the parts connected to the magnetosensitive surfaces 21a and 21b of the magnetoelectric conversion elements 20a and 20b.

[0102] This allows the distance k between the magnetosensitive surfaces 21a and 21b and the body portion 141 to be shortened without the wires 22a and 22b becoming an obstacle. Therefore, the magnetic sensitivity of the magnetoelectric conversion elements 20a and 20b can be increased.

[0103] On the other hand, the distance l between the body portion 141 and the signal processing IC 100 can be increased, so that noise generated by the measurement current flowing through the body portion 141 is less likely to affect the signal processing IC 100. Furthermore, the signal processing IC 100 is less affected by the heat generated in the body portion 141. In addition, if the support portion 154 is made of a conductive material, a shielding effect from external noise can be obtained, and heat can be effectively dissipated to the lead frame 150.

[0104] The distance l between the body portion 141 and the signal processing IC 100 is greater than the distance k between the magnetic sensing surfaces 21a and 21b and the body portion 141. Therefore, even if the distance l between the body portion 141 and the signal processing IC 100 varies, it often does not adversely affect the withstand voltage. Also, even if the distance l between the body portion 141 and the signal processing IC 100 varies, it does not affect the sensitivity. In other words, the height accuracy of surface 151a does not necessarily need to be high. Therefore, although the case where the support portion 154 is separate from the IC suspension portion 151 has been described, the support portion 154 may be formed integrally with the IC suspension portion 151. In that case, the support portion 154 is formed by creating a step in a part of the IC suspension portion 151 by bending, half-through processing, or drawing. By forming a step in this way, the problem of the joint between the IC suspension portion 151 and the support portion 154 peeling off can be eliminated. Alternatively, the support portion 154 does not have a step, and the thickness of the magnetoelectric conversion elements 20a and 20b is made greater than that of the signal processing IC 100, thereby making the distance l greater than the distance k.

[0105] 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.

[0106] 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]

[0107] 10 Current Sensor 20a, 20b Magnetoelectric conversion element 21a, 21b Magnetically sensitive surface 22a, 22b, 108 wire 100 Signal Processing ICs 130 Sealing part 140 Lead Frames 141 Body part 142 Terminal part Terminals 142a and 142b 143 First Conductor Section 144 Second Conductor Section 145 Step section 1414 Part 1 1415 Part 2 1416 Connection section 150 Lead Frames 151 IC suspension section 152 Terminal part 152a terminal 154 Support part 155 Step section 156 Opening 160 Adhesive layer 170 Insulating Sheets

Claims

1. A magnetoelectric conversion element having a magnetosensitive surface and detecting a magnetic field in a direction along the magnetosensitive surface, A current conductor having a first body portion positioned opposite at least a portion of the magnetic surface, through which a measurement current that generates a magnetic field detected by the at least one magnetoelectric conversion element flows, A signal processing IC that processes the signal output from at least one magnetoelectric conversion element, A support portion that supports the second surface opposite to the first surface facing the current conductor of the signal processing IC, The system comprises at least one magnetoelectric conversion element, the first body portion of the current conductor, the signal processing IC, and the support portion, with a sealing portion that seals them together with molded resin. A current sensor in which at least the molded resin is present throughout the space between the signal processing IC and the current conductor.

2. The current sensor according to claim 1, wherein the current conductor is a first lead frame.

3. The current sensor according to claim 1 or 2, wherein the support portion and the first body portion are located at different positions in a first direction intersecting the magnetic surface, and are arranged to overlap at least partially when viewed from the first direction.

4. The current conductor further includes a first terminal portion that is connected to the first body portion and exposed outside the sealing portion, The current sensor according to claim 1, further comprising a second lead frame including a second terminal portion that is located opposite the first terminal portion with respect to the signal processing IC when viewed from a first direction intersecting the magnetic surface, and is electrically connected to the signal processing IC.

5. The current sensor according to claim 4, wherein the entire surface of the first body portion, excluding the portion connected to the first terminal portion, is covered only with the molded resin.

6. The current sensor according to claim 1 or 2, further comprising an insulating sheet disposed over the entire area between the signal processing IC and the first body portion.

7. The current sensor according to claim 1 or 2, wherein the molding resin is made of epoxy resin or a composite material containing epoxy resin.

8. The current sensor according to claim 7, wherein the epoxy resin is a polyaromatic ring resin.

9. The current sensor according to claim 1 or 2, wherein the molding resin comprises epoxy resin and an inorganic filler, and the distance between the current conductor and the magnetic surface is greater than or equal to the maximum diameter of the filler.

10. The current sensor according to claim 1 or 2, wherein the magnetosensitive surface of the at least one magnetoelectric conversion element is covered by the current conductor when viewed from a first direction intersecting the magnetosensitive surface.

11. The first terminal section has a pair of terminals, The current sensor according to claim 4, wherein the first body portion includes a first portion connected to one of the pair of terminals and extending in a second direction along the magnetic surface, a second portion connected to the other of the pair of terminals and extending in the second direction, and a connecting portion extending in a third direction along the magnetic surface and intersecting the second direction, and connecting the first portion and the second portion.

12. The at least one magnetoelectric conversion element is When viewed from a first direction intersecting the magnetic surface, The system includes a first magnetoelectric conversion element located in a position overlapping with the first portion, and a second magnetoelectric conversion element located in a position overlapping with the second portion. The current sensor according to claim 11.

13. When viewed from a first direction intersecting the magnetic sensing surface, if W (mm) is the width in the direction intersecting the extending direction of the first portion of the first body that coincides with the center of the first magnetic sensing surface of the first magnetoelectric conversion element, The current sensor according to claim 12, wherein the center of the first magnetosensitive surface of the first magnetoelectric conversion element is located in a range of 0 mm or more and 0.1 W + 0.3 mm or less from the end of the first portion of the first body facing the second portion, when viewed from the first direction.

14. If, of the first part, the area on the side facing the second part that is not connected to the connecting portion is defined as the first rectangular region, and of the second part, the area on the side facing the first part that is not connected to the connecting portion is defined as the second rectangular region, The current sensor according to claim 12, wherein, when viewed from the first direction, the first magnetoelectric conversion element is located in a position overlapping with the first rectangular region, and the second magnetoelectric conversion element is located in a position overlapping with the second rectangular region.

15. The at least one magnetoelectric conversion element includes a first magnetoelectric conversion element positioned to overlap the first portion when viewed from a first direction intersecting the magnetosensitive surface, and a second magnetoelectric conversion element positioned to overlap the second portion when viewed from the first direction. Viewed from the first direction, the width of the first portion of the first magnetoelectric conversion element that overlaps with the first magnetosensitive surface, in the direction along the first magnetosensitive surface and intersecting the direction in which the measurement current flows, is equal to the width of the second portion of the second magnetoelectric conversion element that overlaps with the second magnetosensitive surface, in the direction along the second magnetosensitive surface and intersecting the direction in which the measurement current flows, as viewed from the first direction. Viewed from the first direction, the distance from the end of the first portion to the center of the first magnetic surface is equal to the distance from the end of the second portion to the center of the second magnetic surface. The current sensor according to claim 11, wherein the signal processing IC measures the measurement current based on the difference signal between the signal output from the first magnetoelectric conversion element and the signal output from the second magnetoelectric conversion element.

16. The first magnetoelectric conversion element is electrically connected to the signal processing IC via a plurality of first wires. The second magnetoelectric conversion element is electrically connected to the signal processing IC via a plurality of second wires. The current sensor according to claim 15, wherein the plurality of first wires and the plurality of second wires are congruent.

17. The plurality of first wires, when viewed from the first direction, extend along the first magnetic surface in the first portion that overlaps with the first magnetic surface, and in a direction that intersects the direction in which the measurement current flows in the first portion. The current sensor according to claim 16, wherein the plurality of second wires, when viewed from the first direction, extend along the second magnetic surface in the second portion that overlaps with the second magnetic surface, and in a direction that intersects the direction in which the measured current flows.

18. The current sensor according to claim 4, wherein the support portion is part of the second lead frame.

19. The current sensor according to claim 1 or 2, wherein, when viewed from a first direction intersecting the magnetic sensing surface, the magnetic sensing surface overlaps with the signal processing IC.

20. The current sensor according to claim 1 or 2, wherein the at least one magnetoelectric conversion element is built into a chip constituting the signal processing IC.

21. The current sensor according to claim 1 or 2, wherein the at least one magnetoelectric conversion element and the signal processing IC are configured on separate chips and electrically connected via a plurality of wires.

22. The current sensor according to claim 4, wherein the support portion is separate from the second lead frame.

23. The signal processing IC and the at least one magnetoelectric conversion element are configured on separate chips and are electrically connected via a plurality of wires. The at least one magnetoelectric conversion element is positioned opposite the signal processing IC in a direction along the magnetosensing surface when viewed from a first direction intersecting the magnetosensing surface. The current sensor according to claim 2 or 22, wherein the distance between the magnetic sensing surface and the current conductor is shorter than the distance between the first surface of the signal processing IC and the current conductor.

24. The current sensor according to claim 23, wherein the surface of the at least one magnetoelectric conversion element opposite to the magnetosensitive surface is closer to the current conductor than the surface of the signal processing IC opposite to the first surface.

25. The current sensor according to claim 23, wherein a bonding ball exists on the signal processing IC side among the plurality of wires.

26. The current sensor according to claim 21, wherein the plurality of wires, when viewed from a first direction intersecting the magnetic surface, do not intersect with the end face of the first body portion.

27. The sealing portion has the first surface on the first surface side of the signal processing IC, The current conductor has a first conductor portion and a second conductor portion located further away from the first conductor portion in a first direction intersecting the magnetic surface from the first surface of the sealing portion. The current sensor according to claim 2, as viewed from a direction along the magnetic sensing surface, the magnetic sensing surface is located between the second surface of the first conductor portion opposite to the first surface of the sealing portion facing the first surface and the second surface of the second conductor portion opposite to the first surface of the sealing portion facing the first surface.

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