Current sensor

Abstract

In a current sensor, the plurality of wires electrically connecting the signal processing IC and the first magnetoelectric conversion element may include a first wire located in a first region on the connecting portion side with respect to the first magnetoelectric conversion element, which is on the second portion side of a first center line that is equally spaced between the side of the first portion on the first magnetoelectric conversion element side and the side of the second portion on the first magnetoelectric conversion element side; a second wire located in a second region on the connecting portion side with respect to the first magnetoelectric conversion element, which is on the first portion side of the first center line; a third wire located in a third region on the first portion side of the first center line, which is on the opposite side of the connecting portion with respect to the first magnetoelectric conversion element; and a fourth wire located in a fourth region on the second portion side of the first center line, which is on the opposite side of the connecting portion with respect to the first magnetoelectric conversion element.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes that by wiring a signal line along the direction in which magnetic flux passes, the induced electromotive force due to the magnetic flux is prevented from being generated in the signal line. Patent Document 2 describes that a metal wiring on an IC is provided with a three-dimensional intersection portion in a metal wiring for inputting the output voltage of a Hall sensor to a signal processing unit provided in the IC so as to suppress the generated induced electromotive force. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-214815 [Patent Document 2] International Publication No. 2013 / 065266

Summary of the Invention

Problems to be Solved by the Invention

[0003] Noise caused by the induced electromotive force generated in a wire that electrically connects a magnetoelectric conversion element and a signal processing IC may affect the measurement accuracy of the measured current by the current sensor.

Means for Solving the Problems

[0004] A current sensor according to one aspect of the present invention may include a first magnetoelectric conversion element. The current sensor may include a signal processing IC that processes a signal output from the first magnetoelectric conversion element. The current sensor may include a first lead frame that includes a pair of primary terminals and a conductor portion connected to the pair of primary terminals, through which a measured current measured by the first magnetoelectric conversion element flows. The current sensor may include a plurality of wires that electrically connect the first magnetoelectric conversion element and the signal processing IC. The conductor portion may have, in plan view, a first portion and a second portion extending in a first direction and connected to each of the pair of primary terminals, and a connecting portion extending in a second direction intersecting the first direction in plan view and connecting the first portion and the second portion. In a plan view, the first magnetoelectric conversion element may be partially surrounded by the first portion, the second portion, and the connecting portion, and may be located at a position that coincides with a first centerline that is equally spaced between the side of the first portion on the first magnetoelectric conversion element side and the side of the second portion on the first magnetoelectric conversion element side. In a plan view, the plurality of wires may include a first wire located in a first region that is on the second portion side of the first centerline and on the connecting portion side with respect to the first magnetoelectric conversion element; a second wire located in a second region that is on the first portion side of the first centerline and on the connecting portion side with respect to the first magnetoelectric conversion element; a third wire located in a third region that is on the first portion side of the first centerline and on the opposite side of the connecting portion with respect to the first magnetoelectric conversion element; and a fourth wire located in a fourth region that is on the second portion side of the first centerline and on the opposite side of the connecting portion with respect to the first magnetoelectric conversion element.

[0005] In the current sensor, the plurality of wires may be located between a third imaginary line extending in the first direction on the side surface of the first portion of the first magnetoelectric conversion element and a fourth imaginary line extending in the first direction on the side surface of the second portion of the first magnetoelectric conversion element, in a plan view.

[0006] In the current sensor, the first magnetoelectric conversion element may have a pair of first terminals to which a drive current is input or an output signal is output, and a pair of second terminals to which the output signal is output when the drive current is input to the pair of first terminals, and to which the drive current is input when the output signal is output from the pair of first terminals. The signal processing IC may have a first pad located in a first region of the circuit surface on which the first magnetoelectric conversion element is mounted and connected to a first wire connected to one of the pair of first terminals, a second pad located in a second region of the circuit surface and connected to a second wire connected to one of the pair of second terminals, a third pad located in a third region of the circuit surface and connected to a third wire connected to the other of the pair of first terminals, and a fourth pad located in a fourth region of the circuit surface and connected to a fourth wire connected to the other of the pair of second terminals.

[0007] In any of the current sensors, the lengths of the first wire, the second wire, the third wire, and the fourth wire may be the same.

[0008] Any of the current sensors may further include a second magnetoelectric element positioned opposite the first magnetoelectric element, with the second portion in between, and a plurality of other wires electrically connecting the second magnetoelectric element and the signal processing IC. At least one of the plurality of other wires may be located between the second magnetoelectric element and the second portion in a plan view.

[0009] Any of the current sensors may further include a second magnetoelectric element positioned opposite the first magnetoelectric element, with the second portion in between, and a plurality of other wires electrically connecting the second magnetoelectric element and the signal processing IC. The plurality of other wires may, in a plan view, be located between a first virtual line extending in the second direction on the side of the second magnetoelectric element on the side of the connecting portion and a second virtual line extending in the second direction on the side of the second magnetoelectric element opposite to the side of the connecting portion.

[0010] In any of the current sensors, at least one of the plurality of other wires may extend from the second magnetoelectric conversion element toward the second portion, and at least one of the other wires may extend in the opposite direction from the second magnetoelectric conversion element toward the second portion.

[0011] Any of the current sensors may further include a second magnetoelectric conversion element positioned symmetrically with respect to the first magnetoelectric conversion element, with the center line of the second portion as the axis of symmetry, and a plurality of other wires electrically connecting the second magnetoelectric conversion element and the signal processing IC. The direction in which the plurality of other wires extend may be asymmetric with respect to the axis of symmetry with respect to the direction in which the plurality of wires extend.

[0012] In any of the current sensors, if, in a plan view, there is a second centerline extending in the first direction and passing through the center of the second magnetoelectric conversion element, and a third centerline extending in the second direction and passing through the center of the second magnetoelectric conversion element, then the plurality of other wires may include, in a plan view, a fifth wire located on the side of the third centerline opposite to the second portion and between the second centerline and the first virtual line, a sixth wire located on the side of the third centerline toward the second portion and between the second centerline and the first virtual line, a seventh wire located on the side of the third centerline toward the second portion and between the second centerline and the second virtual line, and an eighth wire located on the side of the third centerline opposite to the second portion and between the second centerline and the second virtual line.

[0013] In any of the current sensors, the fifth wire, the sixth wire, the seventh wire, and the eighth wire may extend along the second direction in a plan view.

[0014] In any of the current sensors, the second magnetoelectric conversion element may have a pair of third terminals to which a drive current is input or an output signal is output, and a pair of fourth terminals to which the output signal is output when the drive current is input to the pair of third terminals, and to which the drive current is input when the output signal is output from the pair of third terminals.

[0015] The signal processing IC may have, in a plan view, a fifth pad located on the circuit surface on which the second magnetoelectric conversion element is mounted, on the side opposite to the second portion with respect to the third center line and between the second center line and the first virtual line, and connected to the fifth wire connected to one of the pair of third terminals; a sixth pad located on the side of the second portion with respect to the third center line and on the circuit surface between the second center line and the first virtual line, and connected to the sixth wire connected to one of the pair of fourth terminals; a seventh pad located on the side of the second portion with respect to the third center line and on the circuit surface between the second center line and the second virtual line, and connected to the seventh wire connected to the other of the pair of third terminals; and an eighth pad located on the side opposite to the second portion with respect to the third center line and on the circuit surface between the second center line and the second virtual line, and connected to the eighth wire connected to the other of the pair of fourth terminals.

[0016] Any of the current sensors may further include a second magnetoelectric element positioned opposite the first magnetoelectric element, with the second portion in between, and a plurality of other wires electrically connecting the second magnetoelectric element and the signal processing IC. In a plan view, if we define a second centerline extending in the first direction and passing through the center of the second magnetoelectric conversion element, and a third centerline extending in the second direction and passing through the center of the second magnetoelectric conversion element, the plurality of other wires may include a fifth wire located in a fifth region on the opposite side of the second portion from the third centerline and on the connecting portion side with respect to the second centerline, a sixth wire located in a sixth region on the second portion side from the third centerline and on the connecting portion side with respect to the second centerline, a seventh wire located in a seventh region on the second portion side from the third centerline and on the opposite side of the connecting portion with respect to the second centerline, and an eighth wire located in an eighth region on the second portion side from the third centerline and on the opposite side of the connecting portion with respect to the second centerline. The first wire and the third wire may have different lengths. The second wire and the fourth wire may have different lengths.

[0017] In any of the current sensors, the first wire and the fourth wire may be the same length. The second wire and the third wire may be the same length.

[0018] In any of the current sensors, if the first wire is longer than the third wire, the fourth wire may be longer than the second wire. If the first wire is shorter than the third wire, the second wire may be shorter than the fourth wire.

[0019] In any of the current sensors, the signal processing IC may measure the measurement current based on a measurement signal obtained by subtracting the measurement signal output from the first magnetoelectric conversion element from the measurement signal output from the second magnetoelectric conversion element.

[0020] A current sensor according to an aspect of the present invention may include a first magnetoelectric conversion element and a second magnetoelectric conversion element. The current sensor may include a pair of primary terminals and a conductor portion connected to the pair of primary terminals, and may include a first lead frame through which a measurement current measured by the first magnetoelectric conversion element and the second magnetoelectric conversion element flows through the pair of primary terminals and the conductor portion. The current sensor may include a signal processing IC that processes signals output from the first magnetoelectric conversion element and the second magnetoelectric conversion element. The current sensor may include a plurality of wires that connect each of the first magnetoelectric conversion element and the second magnetoelectric conversion element to the signal processing IC. The conductor portion may have a first portion and a second portion that extend in a first direction and are connected to each of the pair of primary terminals, and a connecting portion that extends in a second direction intersecting the first direction in a plan view and connects the first portion and the second portion. In a plan view, the first magnetoelectric conversion element may be located at a position partially surrounded by the first portion, the second portion, and the connecting portion. The second magnetoelectric conversion element may be located at a position facing the first magnetoelectric conversion element with the second portion interposed therebetween. At least one wire that connects the second magnetoelectric conversion element and the signal processing IC among the plurality of wires may exist between the second magnetoelectric conversion element and the second portion.

[0021] 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 can also be inventions.

Brief Description of the Drawings

[0022] [Figure 1A] It is a schematic plan view seen from the ceiling surface side (z-axis direction) of the current sensor according to the present embodiment. [Figure 1B] FIG. 1B is a cross-sectional view taken along line A-A of the current sensor shown in FIG. 1A. [Figure 2] It is a plan view of a lead frame and a magnetoelectric conversion element according to the present embodiment. [Figure 3] It is a plan view of a lead frame and a magnetoelectric conversion element according to the first modification. [Figure 4A]This is a diagram for explaining the induced electromotive force generated in a wire connected to a magnetoelectric conversion element. [Figure 4B] This is a diagram for explaining the induced electromotive force generated in a wire connected to a magnetoelectric conversion element. [Figure 5A] This is a diagram for explaining the induced electromotive force generated in a wire connected to a magnetoelectric conversion element. [Figure 5B] This is a diagram for explaining the induced electromotive force generated in a wire connected to a magnetoelectric conversion element. [Figure 6A] This is a diagram for explaining the induced electromotive force generated in a wire connected to a magnetoelectric conversion element. [Figure 6B] This is a diagram for explaining the induced electromotive force generated in a wire connected to a magnetoelectric conversion element. [Figure 7] This is a plan view of a lead frame and a magnetoelectric conversion element according to a second modification example. [Figure 8] This is a plan view of a lead frame and a magnetoelectric conversion element according to a third modification example.

Embodiments for Carrying Out the Invention

[0023] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution of the invention.

[0024] FIGS. 1A and 1B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the present embodiment. FIG. 1A is a schematic plan view seen from the ceiling surface side (z-axis direction) of the current sensor 10 according to the present embodiment. FIG. 1B is a cross-sectional view taken along line A-A of the current sensor 10 shown in FIG. 1A.

[0025] The coordinates are defined in FIG. 1A as follows: the direction from bottom to top parallel to the paper surface is the x-axis direction, the direction from right to left parallel to the paper surface is the y-axis direction, and the direction from back to front perpendicular to the paper surface is the z-axis direction. Any one of the x-axis, y-axis, and z-axis is orthogonal to the other axes.

[0026] The current sensor 10 comprises 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.

[0027] 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 pair of terminals 142a and 142b is an example of a pair of primary terminals. The conductor portion 141 is sealed within the sealing portion 130 and, together with a part of the terminal portion 142, partially surrounds the magnetoelectric conversion elements 20a and 20b. A measurement current flows through the terminal portion 142 and the conductor portion 141. The pair of terminals 142a and 142b are physically integral 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.

[0028] The lead frame 140 does not need to be manufactured using a form in which multiple conductor portions 141 and terminal portions 142 are connected together; it may also be manufactured using individual metal parts.

[0029] 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 part 154 that holds the signal processing IC 100. The signal processing IC 100 may be fixed to the surface 154a of the holding part 154 via an adhesive layer. The holding portion 151 includes a stepped portion 155 that rises from the holding part 154 towards the conductor portion 141. The stepped portion 155 is formed by recessing the holding portion 154 in the thickness direction (z-axis direction) away from the conductor portion 141 (towards the bottom surface of the sealing portion 130). The stepped portion 155 may be formed by performing a half-through processing on the lead frame 150. Note that the stepped portion 155 is not required.

[0030] Multiple terminals 152a are physically integrated with the holding portion 151 and are exposed outside the sealing portion 130. The lead frame 150 is an example of a second lead frame. The lead frame 140 and lead frame 150 may be made of a conductive material mainly composed of copper.

[0031] Here, the x-axis is the direction along the planes of lead frames 140 and 150, and the direction in which the multiple terminals 152a are arranged. The y-axis is the direction along the planes of lead frames 140 and 150, and 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 lead frames 140 and 150, the direction intersecting the circuit plane of the signal processing IC 100, and the thickness direction of the sealing portion 130.

[0032] 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.

[0033] The magnetoelectric elements 20a and 20b are electrically connected to the signal processing IC 100 via a plurality of wires 22a and 22b. The magnetoelectric 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 elements 20a and 20b by connecting the plurality of pads 23a and 23b to the plurality of wires 22a and 22b. In this embodiment, an example in which the current sensor 10 includes two magnetoelectric elements 20a and 20b will be described. However, the current sensor 10 only needs to be equipped with one or more magnetoelectric conversion elements.

[0034] 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.

[0035] 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.

[0036] 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. The magnetoelectric conversion element 20a is an example of a first magnetoelectric conversion element, and the magnetoelectric conversion element 20b is an example of a second magnetoelectric conversion element.

[0037] 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 composed of separate magnetoelectric conversion elements 20a and 20b and the signal processing IC 100, and does not have a monolithic structure.

[0038] 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 signal, the signal processing circuit corrects the measured current flowing through the conductor part 141 and outputs an output signal indicating the corrected current value via terminal 152a. The signal processing circuit subtracts the output signal of magnetoelectric conversion element 20b from the output signal of magnetoelectric conversion element 20a, amplifies the result, calculates the current value of the measured current based on the amplified output signal, and outputs an output signal indicating the current value. Meanwhile, noise components contained in the output signals of magnetoelectric conversion element 20a and magnetoelectric conversion element 20b are reduced based on their difference.

[0039] Figure 2 is a plan view of the lead frame 140 and magnetoelectric conversion elements 20a and 20b according to this embodiment. The conductor portion 141 constituting the lead frame 140 has, in plan view, a first portion 1411 and a second portion 1412 that extend in the y-axis direction and are connected to a pair of terminals 142a and 142b, respectively. Furthermore, the conductor portion 141 has a connecting portion 1413 that extends in the x-axis direction intersecting the y-direction in plan view and connects the first portion 1411 and the second portion 1412.

[0040] In a plan view, the magnetoelectric conversion element 20a is partially surrounded by the first part 1411, the second part 1412, and the connecting part 1413. The magnetoelectric conversion element 20b is positioned opposite the magnetoelectric conversion element 20a, with the second part 1412 in between.

[0041] The magnetoelectric conversion element 20a has four terminals 21a1, 21a2, 21a3, and 21a4. Terminals 21a1 and 21a3, located diagonally opposite each other, form a pair of first terminals, and terminals 21a2 and 21a4, also located diagonally opposite each other, form a pair of second terminals. Terminal 21a1 is electrically connected to pad 23a1 on the circuit surface of the signal processing IC 100 via wire 22a1. Similarly, terminals 21a2, 21a3, and 21a4 are electrically connected to pads 23a2, 23a3, and 23a4 on the circuit surface of the signal processing IC 100 via wires 22a2, 22a3, and 22a4. When a drive current flows through terminals 21a2 and 21a4, output signals corresponding to the magnetic field are output from terminals 21a1 and 21a3. On the other hand, when a drive current flows through terminals 21a1 and 21a3, output signals corresponding to the magnetic field are output from terminals 21a2 and 21a4. Wires 22a1, 22a2, 22a3, and 22a4 are examples of the first, second, third, and fourth wires, respectively.

[0042] The magnetoelectric conversion element 20b has four terminals 21b1, 21b2, 21b3, and 21b4. Terminals 21b1 and 21b3, located diagonally opposite each other, form a pair of third terminals, and terminals 21b2 and 21b4, also located diagonally opposite each other, form a pair of fourth terminals. Terminal 21b1 is electrically connected to pad 23b1 on the circuit surface of the signal processing IC 100 via wire 22b1. Similarly, terminals 21b2, 21b3, and 21b4 are electrically connected to pads 23b2, 23b3, and 23b4 on the circuit surface of the signal processing IC 100 via wires 22b2, 22b3, and 22b4. When a drive current flows through terminals 21b2 and 21b4, output signals corresponding to the magnetic field are output from terminals 21b1 and 21b3. On the other hand, when drive current flows through terminals 21b1 and 21b3, output signals corresponding to the magnetic field are output from terminals 21b2 and 21b4. Wires 22b1, 22b2, 22b3, and 22b4 are examples of the 5th, 6th, 7th, and 8th wires, respectively.

[0043] Incidentally, the magnetoelectric conversion elements 20a and 20b have an offset voltage (unbalanced voltage) which is a non-zero, finite voltage output from their terminals even when no magnetic field is generated. Therefore, the signal processing IC 100 drives the magnetoelectric conversion elements 20a and 20b using a driving method commonly known as the spinning current method or connection commutation method, in order to cancel out the offset voltage generated by the magnetoelectric conversion elements 20a and 20b.

[0044] For example, the signal processing IC 100 periodically switches between a period in which a drive current flows through a pair of first terminals (a pair of third terminals) of the magnetoelectric conversion element 20a (20b) and outputs an output signal from a pair of second terminals (a pair of fourth terminals), and a period in which a drive current flows through a pair of second terminals (a pair of fourth terminals) of the magnetoelectric conversion element 20a (20b) and outputs an output signal from a pair of first terminals (a pair of third terminals). By integrating the difference signals of these output signals, the IC cancels out the offset voltage.

[0045] The signal processing IC 100 subtracts the measurement signal of the magnetoelectric conversion element 20a, which is obtained by integrating the difference signals of each output signal output from a pair of first terminals and the difference signals of each output signal output from a pair of second terminals using an integrator, from the measurement signal of the magnetoelectric conversion element 20b, which is obtained by integrating the difference signals of each output signal output from a pair of third terminals and the difference signals of each output signal output from a pair of fourth terminals using an integrator, and measures the measurement current flowing through the conductor part 141 based on the measurement signal after subtraction.

[0046] Figure 3 is a plan view of the lead frame 140 and magnetoelectric conversion elements 20a and 20b according to the first modified example. In the magnetoelectric conversion element 20b according to the first modified example, the direction in which the wires 22 (22b1 to 22b4) for electrically connecting to the signal processing IC 100 extend is different from that of the magnetoelectric conversion element 20b shown in Figure 1A.

[0047] Here, when a current 200 flows through the conductor portion 141 in the direction of the arrow shown in Figure 3, current flows in the positive y-axis direction through the first portion 1411 and in the negative y-axis direction through the second portion 1412. In this case, as shown in Figures 4A and 4B, a magnetic flux 210 in the negative x-axis direction passes through the wires 22a2 and 22a3 of the magnetoelectric conversion element 20a, and a magnetic flux 212 in the positive y-axis direction passes through the wires 22a1 and 22a4 of the magnetoelectric conversion element 20a. These magnetic fluxes induce an electromotive force in wire 22a1 in the direction of arrow 201. Similarly, electromotive forces are induced in wires 22a2, 22a3, and 22a4 in the directions of arrows 202, 203, and 204. Therefore, negative polarity induced electromotive forces are generated at pads 23a1 and 23a3 connected to the pair of first terminals, and positive polarity induced electromotive forces are generated at pads 23a2 and 23a4 connected to the pair of second terminals. As described above, the output signals output from the pair of terminals have the difference taken to cancel out the offset voltage. Therefore, as shown in Figure 3, if the wires 22a1, 22a2, 22a3, and 22a4 extend in a plan view so that they have a component in the y direction, and the lengths of each wire 22a1, 22a2, 22a3, and 22a4 are the same, the noise due to the induced electromotive forces will cancel each other out. The concept that the lengths of wires 22a1, 22a2, 22a3, and 22a4 are the same includes the concept that the lengths of wires 22a1, 22a2, 22a3, and 22a4 are substantially the same. The lengths of wires 22a1, 22a2, 22a3, and 22a4 may differ from each other, for example, with a variation of ±500 μm, as long as the effect of noise due to induced electromotive force is negligible.

[0048] In other words, if the magnetoelectric conversion element 20a is located in a position where it overlaps with the first core wire L1, which is equally spaced between the side S1 of the first part 1411 on the magnetoelectric conversion element 20a side and the side S2 of the second part 1412 on the magnetoelectric conversion element 20a side, in a plan view, then the influence of induced electromotive force can be suppressed by having the respective wires 22a1, 22a2, 22a3, and 22a4 in the following positions.

[0049] Wire 22a1 should be located in the first region A1, which is on the second portion 1412 side of the first centerline L1 and on the connecting portion 1413 side with respect to the magnetoelectric conversion element 20a. Wire 22a2 should be located in the second region A2, which is on the first portion 1411 side of the first centerline L1 and on the connecting portion 1413 side with respect to the magnetoelectric conversion element 20a. Wire 22a3 should be located in the third region A3, which is on the first portion 1411 side of the first centerline L1 and on the opposite side of the connecting portion 1413 with respect to the magnetoelectric conversion element 20a. Wire 22a4 should be located in the fourth region A4, which is on the second portion 1412 side of the first centerline L1 and on the opposite side of the connecting portion 1413 with respect to the magnetoelectric conversion element 20a.

[0050] On the other hand, if the wires 22b1, 22b2, 22b3, and 22b4 of the magnetoelectric conversion element 20b extend in the same direction as the wires 22a1, 22a2, 22a3, and 22a4 of the magnetoelectric conversion element 20a, as shown in Figure 3 in a plan view, then magnetic flux passes through each of the wires 22b1, 22b2, 22b3, and 22b4 in the direction shown in Figures 5A and 5B. That is, a magnetic flux 214 in the positive x-axis direction passes through wires 22b1 and 22b2. Similarly, a magnetic flux 214 in the positive x-axis direction passes through wires 22b3 and 22b4. Due to these magnetic fluxes, an induced electromotive force is generated in wire 22b1 in the direction of arrow 205. Similarly, induced electromotive forces are generated in wires 22b2, 22b3, and 22b4 in the directions of arrows 206, 207, and 208.

[0051] Therefore, a negative polarity induced electromotive force is generated at pad 23b1 connected to one of the pair of third terminals, and a positive polarity induced electromotive force is generated at pad 23b3 connected to the other of the pair of third terminals. Similarly, a negative polarity induced electromotive force is generated at pad 23b2 connected to one of the pair of fourth terminals, and a positive polarity induced electromotive force is generated at pad 23b4 connected to the other of the pair of fourth terminals. In other words, induced electromotive forces of different polarities are generated at each pair of terminals. Consequently, noise generated by the induced electromotive forces from the difference signal of each output signal output from each pair of terminals is not canceled out.

[0052] Therefore, at least one of the wires 22b1, 22b2, 22b3, and 22b4 may be located between the second part 1412 and the magnetoelectric conversion element 20b in a plan view, in order to suppress the influence of the magnetic flux generated when current flows through the second part 1412. By having the wire extend in a direction along the direction of the magnetic flux in this way, the induced electromotive force caused by the magnetic flux is less likely to be generated in the wire. Thus, according to the embodiment shown in Figure 2, the influence of noise associated with the induced electromotive force can be reduced compared to the first modified example shown in Figure 3.

[0053] As shown in Figure 2, it is preferable that the wires 22b1, 22b2, 22b3, and 22b4 exist in a plan view between a first virtual line L4 extending in the x-axis direction on the side surface of the magnetoelectric conversion element 20b on the side of the connecting portion 1413 and a second virtual line L5 extending in the x-axis direction on the side surface of the magnetoelectric conversion element 20b opposite to the side of the connecting portion 1413.

[0054] Preferably, at least one of the wires 22b1, 22b2, 22b3, and 22b4 extends from the magnetoelectric conversion element 20b toward the second section 1412, and at least one other of the wires 22b1, 22b2, 22b3, and 22b4 extends in the opposite direction from the magnetoelectric conversion element 20b toward the second section 1412.

[0055] Preferably, the direction in which wires 22b1, 22b2, 22b3, and 22b4 extend is asymmetrical to the direction in which wires 22a1, 22a2, 22a3, and 22a4 extend, when the center line L3, which extends in the x-axis direction and passes through the center of the magnetoelectric conversion element 20b, is used as the axis of symmetry.

[0056] By aligning the extension directions of wires 22b1, 22b2, 22b3, and 22b4 as described above, a magnetic flux in the positive x-axis direction is generated in each of the wires 22b1, 22b2, 22b3, and 22b4 due to the flow of current in the negative y-axis direction in the second portion 1412, as shown in Figures 6A and 6B. However, since each of the wires 22b1, 22b2, 22b3, and 22b4 extends in the x-axis direction, it is difficult for an induced electromotive force to be generated by this magnetic flux. Therefore, noise generated by an induced electromotive force is less likely to occur from the difference signal of each output signal output from a pair of terminals.

[0057] Figure 7 is a plan view of the lead frame 140 and magnetoelectric conversion elements 20a and 20b according to a second modified example. As shown in Figure 7, it is preferable that the wires 22a1, 22a2, 22a3, and 22a4 are located in a plan view between a first virtual line L6 extending in the y-axis direction on the side surface of the first portion 1411 of the magnetoelectric conversion element 20a and a first virtual line L7 extending in the y-axis direction on the side surface of the second portion 1412.

[0058] Preferably, at least one of the wires 22a1, 22a2, 22a3, and 22a4 extends from the magnetoelectric conversion element 20a toward the connecting portion 1413, and at least one of the other wires 22a1, 22a2, 22a3, and 22a4 extends in the opposite direction from the magnetoelectric conversion element 20a toward the connecting portion 1413.

[0059] Preferably, the direction in which wires 22a1, 22a2, 22a3, and 22a4 extend is asymmetrical to the direction in which wires 22b1, 22b2, 22b3, and 22b4 extend, when the center line L2, which extends in the y-axis direction and passes through the center of the magnetoelectric conversion element 20a, is used as the axis of symmetry.

[0060] By aligning the extension directions of wires 22a1, 22a2, 22a3, and 22a4 as described above, a magnetic flux is generated in the y-axis direction when current flows through the connection portion 1413 in the x-axis direction. However, since each of the wires 22a1, 22a2, 22a3, and 22a4 extends in the y-axis direction, it is difficult for an induced electromotive force to be generated by this magnetic flux. Therefore, noise generated by an induced electromotive force is less likely to occur from the difference signal of each output signal output from a pair of terminals.

[0061] Figure 8 is a plan view of the lead frame 140 and magnetoelectric conversion elements 20a and 20b according to the third modified example. In the third modified example, the lengths of the wires connected to the pair of first terminals (terminals 21a1 and 21a3) and the lengths of the wires connected to the pair of second terminals (terminals 21a2 and 21a4) are different. More specifically, wire 22a1 connected to one of the pair of first terminals is longer than wire 22a3 connected to the other of the pair of first terminals. Also, wire 22a4 connected to one of the pair of second terminals is longer than wire 22a2 connected to the other of the pair of second terminals. By making the lengths of the wires connected to the pair of terminals different in this way, noise components generated by induced electromotive force remain in the difference signal between the respective output signals output from the pair of terminals without being canceled out. However, since the measurement signal of magnetoelectric conversion element 20a and the measurement signal of magnetoelectric conversion element 20b are subtracted, if the polarity and magnitude of the noise components generated by induced electromotive force included in the measurement signals are the same, those noise components will cancel each other out. In other words, by adjusting the lengths of wires 22a1, 22a2, 22a3, and 22a4 so that the noise components output from magnetoelectric conversion elements 20a and 20b cancel each other out, it is possible to prevent noise components generated by induced electromotive force from affecting the measurement accuracy of the measurement current of the signal processing IC 100.

[0062] In the third modified example, if the second center line L2 extends in the x-axis direction and passes through the center of the magnetoelectric conversion element 20b, and the third center line L3 extends in the y-axis direction and passes through the center of the magnetoelectric conversion element 20b, then wire 22b1 should be located in the fifth region B1, which is on the opposite side of the second portion 1412 from the third center line L3 and on the side of the connecting portion 1413 from the second center line L2. Wire 22b2 should be located in the second region B2, which is on the side of the second portion 1412 from the third center line L3 and on the side of the connecting portion 1413 from the second center line L2. Wire 22a4 should be located in the seventh region B3, which is on the side of the second portion 1412 from the third center line L3 and on the opposite side of the connecting portion 1413 from the second center line L2. Wire 22b4 should be located in the eighth region B4, which is on the opposite side of the second portion 1412 from the third centerline L3 and on the opposite side of the connecting portion 1413 from the second centerline L2. Wires 22b1, 22b2, 22b3, and 22b4 may be of the same length and may extend in the direction along the y-axis in a plan view.

[0063] In the third modified example, an example was described in which wires 22a1 and 22a4 are longer than wires 22a2 and a3. However, if the polarity of the measurement signal output by the magnetoelectric conversion element 20b is different, wires 22a1 and 22a4 may also be shorter than wires 22a2 and a3.

[0064] As described above, with the current sensor 10 according to this embodiment, noise caused by the induced electromotive force generated in the wires electrically connecting the magnetoelectric conversion elements 20a and 20b and the signal processing IC 100 is canceled out during the signal processing process, thus preventing it from affecting the measurement accuracy of the current measured by the current sensor 10.

[0065] 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.

[0066] 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]

[0067] 10 Current Sensor 20a, 20b Magnetoelectric conversion element Terminals 21a1, 21a1, 21a3, 21a4 Terminals 21b1, 21b1, 21b3, 21b4 22a1, 22a2, 22a3, 22a4, 108 wire 22b1, 22b2, 22b3, 22b4 wires 23a1, 23a2, 23a3, 23a4 pads 23b1, 23b2, 23b3, 23b4 pads 100 Signal Processing ICs 130 Sealing part 140 Lead Frames 141 Conductor section 1411 Part 1 1412 Part 2 1413 Connecting part 142 Terminal section Terminals 142a and 142b 150 Lead Frames 151 Holding part 152 Terminal section 152a terminal 154 Holding part 155 Step section

Claims

1. First magnetoelectric conversion element, A signal processing IC that processes the signal output from the first magnetoelectric conversion element, A first lead frame includes a pair of primary terminals and a conductor portion connected to the pair of primary terminals, through which the measurement current measured by the first magnetoelectric conversion element flows via the pair of primary terminals and the conductor portion, Multiple wires electrically connect the first magnetoelectric conversion element and the signal processing IC. Equipped with, The conductor portion has, in a plan view, a first portion and a second portion that extend in a first direction and are connected to each of the pair of primary terminals, and a connecting portion that extends in a second direction intersecting the first direction in a plan view and connects the first portion and the second portion. In a plan view, the first magnetoelectric conversion element is partially surrounded by the first portion, the second portion, and the connecting portion, and is located at a position that coincides with a first centerline that is equally spaced between the side of the first portion on the side of the first magnetoelectric conversion element and the side of the second portion on the side of the first magnetoelectric conversion element. In a plan view, the plurality of wires are, A first wire located in the first region on the connecting portion side with respect to the first magnetoelectric conversion element, which is on the second portion side of the first center line, A second wire is located in a second region that is on the first portion side of the first center line and on the connecting portion side with respect to the first magnetoelectric conversion element, A third wire located in a third region that is on the first portion side of the first center line and on the opposite side of the connecting portion from the first magnetoelectric conversion element, The fourth wire is located on the second portion side of the first center line and in the fourth region opposite to the connecting portion with respect to the first magnetoelectric conversion element. A current sensor, including one.

2. The current sensor according to claim 1, wherein the plurality of wires are located, in a plan view, between a third imaginary line extending in the first direction on the side surface of the first portion of the first magnetoelectric conversion element and a fourth imaginary line extending in the first direction on the side surface of the second portion of the first magnetoelectric conversion element.

3. The first magnetoelectric conversion element has a pair of first terminals to which a drive current is input or an output signal is output, and a pair of second terminals to which the output signal is output when the drive current is input to the pair of first terminals, and to which the drive current is input when the output signal is output from the pair of first terminals. The aforementioned signal processing IC is A first pad is located in a first region of the circuit surface on which the first magnetoelectric conversion element is mounted, and is connected to a first wire that is connected to one of the pair of first terminals, A second pad located in the second region of the circuit surface and connected to the second wire which is connected to one of the pair of second terminals, A third pad located in the third region of the circuit surface and connected to the third wire which is connected to the other of the pair of first terminals, A fourth pad located in the fourth region of the circuit surface is connected to the fourth wire which is connected to the other of the pair of second terminals. The current sensor according to claim 1, having the following features.

4. The current sensor according to claim 1, wherein the lengths of the first wire, the second wire, the third wire, and the fourth wire are all the same.

5. A second magnetoelectric conversion element is positioned opposite the first magnetoelectric conversion element, with the second portion in between. The system further comprises a plurality of other wires that electrically connect the second magnetoelectric conversion element and the signal processing IC, The current sensor according to claim 1, wherein at least one of the plurality of other wires is located between the second magnetoelectric conversion element and the second portion in a plan view.

6. A second magnetoelectric conversion element is positioned opposite the first magnetoelectric conversion element, with the second portion in between. The system further comprises a plurality of other wires that electrically connect the second magnetoelectric conversion element and the signal processing IC, The current sensor according to claim 1, wherein the plurality of other wires are located, in a plan view, between a first virtual line extending in the second direction on the side surface of the second magnetoelectric conversion element on the side of the connecting portion and a second virtual line extending in the second direction on the side surface of the second magnetoelectric conversion element opposite to the side surface of the connecting portion.

7. The current sensor according to claim 5, wherein at least one of the plurality of other wires extends from the second magnetoelectric conversion element toward the second portion, and at least one of the other wires extends from the second magnetoelectric conversion element in the opposite direction to the second portion.

8. A second magnetoelectric conversion element is positioned symmetrically with respect to the first magnetoelectric conversion element, with the center line of the second part as the axis of symmetry, sandwiching the second part. The system further comprises a plurality of other wires that electrically connect the second magnetoelectric conversion element and the signal processing IC, The current sensor according to claim 1, wherein the direction in which the plurality of other wires extend is asymmetric with respect to the axis of symmetry with respect to the direction in which the plurality of wires extend.

9. In a plan view, if we define a second center line extending in the first direction and passing through the center of the second magnetoelectric conversion element, and a third center line extending in the second direction and passing through the center of the second magnetoelectric conversion element, The aforementioned multiple other wires, in plan view, A fifth wire located on the opposite side of the second portion from the third center line, and between the second center line and the first imaginary line, A sixth wire located on the second portion side with respect to the third center line, and between the second center line and the first imaginary line, A seventh wire located on the second portion side with respect to the third center line, and between the second center line and the second virtual line, The eighth wire is located on the opposite side of the third center line from the second portion, and between the second center line and the second imaginary line. The current sensor according to claim 6, including the current sensor described in claim 6.

10. The current sensor according to claim 9, wherein, in a plan view, the fifth wire, the sixth wire, the seventh wire, and the eighth wire extend along the second direction.

11. The second magnetoelectric conversion element has a pair of third terminals to which a drive current is input or an output signal is output, and a pair of fourth terminals to which the output signal is output when the drive current is input to the pair of third terminals, and to which the drive current is input when the output signal is output from the pair of third terminals. The aforementioned signal processing IC, in plan view, A fifth pad is located on the circuit surface on which the second magnetoelectric conversion element is mounted, on the side opposite to the second portion with respect to the third center line and between the second center line and the first virtual line, and is connected to the fifth wire which is connected to one of the pair of third terminals, A sixth pad located on the second portion side with respect to the third center line and on the circuit plane between the second center line and the first virtual line, and connected to the sixth wire which is connected to one of the pair of fourth terminals, A seventh pad located on the second portion side with respect to the third center line and on the circuit plane between the second center line and the second virtual line, and connected to the seventh wire which is connected to the other of the pair of third terminals, An eighth pad located on the circuit plane between the second center line and the second virtual line, on the opposite side of the third center line from the second portion, and connected to the eighth wire which is connected to the other of the pair of fourth terminals. The current sensor according to claim 9, having the following features.

12. A second magnetoelectric conversion element is positioned opposite the first magnetoelectric conversion element, with the second portion in between. The system further comprises a plurality of other wires that electrically connect the second magnetoelectric conversion element and the signal processing IC, In a plan view, if we define a second center line extending in the first direction and passing through the center of the second magnetoelectric conversion element, and a third center line extending in the second direction and passing through the center of the second magnetoelectric conversion element, The aforementioned multiple other wires are, A fifth wire located in a fifth region that is on the opposite side of the second portion from the third center line and on the connecting portion side with respect to the second center line, A sixth wire located on the second portion side of the third center line and in the sixth region on the connecting portion side with respect to the second center line, A seventh wire located in a seventh region that is on the second portion side of the third center line and on the opposite side of the connecting portion from the second center line, The eighth wire is located on the second portion side of the third center line and in the eighth region on the opposite side of the connecting portion from the second center line. It has, The first wire and the third wire are of different lengths. The current sensor according to claim 1, wherein the second wire and the fourth wire are of different lengths.

13. The first wire and the fourth wire are of the same length. The current sensor according to claim 12, wherein the second wire and the third wire are of the same length.

14. If the first wire is longer than the third wire, then the fourth wire is longer than the second wire. The current sensor according to claim 12, wherein if the first wire is shorter than the third wire, the second wire is shorter than the fourth wire.

15. The current sensor according to any one of claims 5 to 14, wherein the signal processing IC measures the measurement current based on a measurement signal obtained by subtracting the measurement signal output from the first magnetoelectric conversion element from the measurement signal output from the second magnetoelectric conversion element.

16. First magnetoelectric conversion element, The second magnetoelectric conversion element, A first lead frame includes a pair of primary terminals and a conductor portion connected to the pair of primary terminals, through which the measurement current measured by the first magnetoelectric conversion element and the second magnetoelectric conversion element flows via the pair of primary terminals and the conductor portion, A signal processing IC that processes the signals output from the first magnetoelectric conversion element and the second magnetoelectric conversion element, A plurality of wires connecting the first magnetoelectric conversion element and the second magnetoelectric conversion element to the signal processing IC Equipped with, The conductor portion has a first portion and a second portion that extend in a first direction and are connected to each of the pair of primary terminals, and a connecting portion that extends in a second direction that intersects the first direction in a plan view and connects the first portion and the second portion. In a plan view, the first magnetoelectric conversion element is located in a position partially surrounded by the first portion, the second portion, and the connecting portion. The second magnetoelectric conversion element is located opposite the first magnetoelectric conversion element, with the second portion in between. Of the plurality of wires, at least one wire connecting the second magnetoelectric conversion element and the signal processing IC is a current sensor located between the second magnetoelectric conversion element and the second portion.

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