Current sensor
The current sensor design addresses overheating issues by concentrating current density near inner surfaces using voids and proximity effects, effectively preventing circuit damage from overcurrents.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ASAHI KASEI MICRODEVICES CORP
- Filing Date
- 2024-10-21
- Publication Date
- 2026-05-07
AI Technical Summary
Current sensors fail to effectively handle instantaneous overcurrents without damaging the primary and secondary circuits due to overheating and melting of the conductor, especially when high-frequency components are present.
A current sensor design with a conductor having specific voids and dimensions that concentrate current density near the inner surfaces, utilizing the proximity effect to localize heat generation and fuse function, thereby preventing damage to adjacent circuits.
The design effectively localizes heat generation and melts the conductor in a controlled manner, preventing damage to primary and secondary circuits by concentrating high-frequency current near inner surfaces, achieving both high sensitivity and protection against overcurrents.
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Figure 2026074521000001_ABST
Abstract
Description
[Technical Field]
[0001] This invention relates to a current sensor. [Background technology]
[0002] A current sensor is known in which a conductor through which the current to be measured flows and a magnetoelectric conversion element adjacent to the conductor are sealed within a package, and the amount of current is detected by detecting the strength of the magnetic field generated when the current to be measured flows through the conductor using the magnetoelectric conversion element and converting it into an electrical signal. In such a current sensor, in order to concentrate the magnetic field on the magnetoelectric conversion element and improve detection sensitivity, the cross-sectional area of the conductor portion adjacent to the magnetoelectric conversion element inside the package is made smaller than the cross-sectional area of the conductor portion located at the periphery of the package, thereby increasing the current density in the conductor. As a result, when an instantaneous overcurrent (for example, having a high-frequency component of 1 MHz) flows due to a failure in the system being measured by the current sensor, the conductor inside the package overheats and melts, allowing the current sensor to function as a fuse. Patent Document 1 discloses a pyroelectric circuit breaker that cuts the conductor in response to an overcurrent and prevents further damage by discharging the arc discharge generated at that time to the splitter side. Thus, it is desirable that the current sensor functions as a fuse when an overcurrent flows and does not damage the primary and secondary circuits. [Prior art document] [Patent] [Patent Document 1] International Publication No. 2017 / 136221 [Overview of the project] [Means for solving the problem]
[0003] In a first embodiment of the present invention, a conductor having a first terminal portion for inputting current, arranged on one side in the first axial direction; a second terminal portion for outputting current, spaced apart from the first terminal portion in the second axial direction intersecting the first axial direction; a turn portion arranged on the other side in the first axial direction relative to the first terminal portion; a first body portion connecting one end of the turn portion to the first terminal portion; and a second body portion spaced apart from the first body portion in the second axial direction connecting the other end of the turn portion to the second terminal portion; a magnetic sensor arranged on or near the conductor; and a seal that encloses the turn portion, the first body portion, the second body portion, and the magnetic sensor of the conductor, and the first terminal portion and A current sensor is provided, comprising a package exposing the second terminal portion, wherein at least one of the first and second body portions includes a parallel section having at least one void, and, viewed from a third direction intersecting the first and second axial directions, the cross-sectional area of a first continuous cross section that intersects the inner contour surface of the conductor perpendicularly, and is defined between the inner contour surface of the conductor within the parallel section and the inner surface of the void located furthest from the inner contour surface of the conductor among the at least one void, is smaller than the cross-sectional area of other continuous cross sections between the inner contour surface of the conductor outside the parallel section and the outer contour surface of the conductor.
[0004] In a second embodiment of the present invention, a conductor having a first terminal portion for inputting current, arranged on one side in the first axial direction; a second terminal portion for outputting current, spaced apart from the first terminal portion in the second axial direction intersecting the first axial direction; a turn portion arranged on the other side in the first axial direction relative to the first terminal portion; a first body portion connecting one end of the turn portion to the first terminal portion; and a second body portion spaced apart from the first body portion in the second axial direction connecting the other end of the turn portion to the second terminal portion; a magnetic sensor arranged on or near the conductor; and a package that seals the turn portion, the first body portion, the second body portion, and the magnetic sensor of the conductor, and exposes the first terminal portion and the second terminal portion. A current sensor is provided, wherein at least one of the first body portion and the second body portion includes a parallel section having at least one void, and when viewed from a third direction intersecting the first axial direction and the second axial direction, the dimensions of the cross section in the parallel section are smaller than the dimensions of the cross section in the portion of the conductor outside the parallel section, with respect to the cross section from the inner contour line of the conductor to the point where a straight line drawn perpendicular to the contour line first intersects with another contour line of the conductor, and the dimensions of the cross section in the portion of the conductor outside the parallel section are smaller than the sum of the dimensions of the multiple cross sections in the parallel section, with respect to the cross section from the inner contour line of the conductor to the outer contour line of the conductor.
[0005] It should be noted that the above summary of the invention does not enumerate all of its features. Furthermore, subcombinations of these features may also constitute an invention. [Brief explanation of the drawing]
[0006] [Figure 1] The internal configuration of the current sensor according to this embodiment is shown in a top view. [Figure 2A] The schematic configuration of the sensor unit is shown. [Figure 2B] The definition of rectangularity is shown below. [Figure 3A] This section defines the shape and size of the conductor for simulation (conductor width and internal region width). [Figure 3B] The analysis result of the density distribution of the surge current (1 MHz) flowing in the conductor is shown. [Figure 3C] The analysis result of the heat generation amount (average Joule heat) due to the surge current flowing in the conductor with respect to the width of the conductor is shown. [Figure 4A] The definition of the shape and size of the conductor for simulation (width of the conductor, width of the internal region, position of the hole) is shown. [Figure 4B] The analysis result of the heat generation amount (average Joule heat) due to the current flowing in the conductor with respect to the position of the hole in the conductor is shown. [Figure 5A] The surge current concentrated and flowing inside the conductor due to the proximity effect is shown. [Figure 5B] The DC current flowing and spreading over the entire conductor is shown. [Figure 6A] The fuse operation of the conductor (first phase) is shown. [Figure 6B] The fuse operation of the conductor (second phase) is shown. [Figure 7A] The definition of the shape and size of the conductor for simulation (width of the conductor, width of the internal region, position of the hole, width of the slit) is shown. [Figure 7B] The analysis result of the heat generation amount (average Joule heat) due to the current flowing in the conductor with respect to the width of the slit in the conductor is shown. [Figure 8] The internal configuration of the current sensor with a fault detection function is shown in a top view. [Figure 9] The arrangement of the conductor, insulating layer, and magnetic sensor is shown in a top view. [Figure 10A] The configuration of the mounting substrate on which the current sensor is mounted is shown in a top view. [Figure 10B] The arrangement of the current sensor and footprint is shown in a top view. [Figure 11A] The configuration of the current sensor according to the first modification example is shown in a top view. [Figure 11B] The configuration of the current sensor according to the second modification example is shown in a top view. [Figure 11C] The configuration of the current sensor according to the third modification example is shown in a top view. [Figure 11D] The configuration of the current sensor according to the fourth modified example is shown in a top view. [Figure 11E] The configuration of the current sensor according to the fifth modified example is shown in a top view. [Figure 11F] The configuration of the current sensor according to the sixth modified example is shown in a top view. [Modes for carrying out the invention]
[0007] 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.
[0008] Figure 1 shows the internal configuration of the current sensor 1 according to this embodiment, viewed from above with the package 10 visible. Here, the vertical direction is defined as the vertical direction, the horizontal direction as the horizontal direction, and the direction intersecting these two directions as the height direction. The current sensor 1 is a sensor that measures the amount of current to be measured by detecting the magnetic field generated around the conductor 40 when the current to be measured flows through it, and comprises a package 10, a magnetic sensor 30, a conductor 40, and a plurality of signal terminals 50. In this specification, the terms "contour surface" and "contour line" are used for the conductor 40, but the contour surface refers to the outer surface or a part thereof that forms the contour (outer shape) of the conductor 40, and the contour line refers to the outer shape line that forms the contour (shape) of the conductor 40 in a top view (view in the height direction).
[0009] Package 10 is a component that protects each part of the current sensor 1, sealing the turn portion 43 of the conductor 40, the first body portion 42a, the second body portion 42b, the magnetic sensor 30, and the base ends of the multiple signal terminals 50, while exposing the first terminal portion 41a and the second terminal portion 41b from one side in the vertical direction (bottom side in the drawing) and the tips of the multiple signal terminals 50 from the other side in the vertical direction (top side in the drawing). Package 10 is formed into a flat rectangular parallelepiped by molding using a sealing resin with excellent insulating properties, such as epoxy.
[0010] The magnetic sensor 30 is a sensor that detects the magnetic field generated when a current to be measured flows through the conductor 40, and includes a substrate 31 and two sensor parts 20. The magnetic sensor 30 is placed on the conductor 40. Although the magnetic sensor 30 is described as including two sensor parts 20, it may instead include only one.
[0011] The substrate 31 is a plate-shaped member placed on the conductor 40 via an insulating layer 39 (see Figure 9), and supports two sensor units 20 thereon. Multiple wires (not shown) connected to the sensor units 20 are laid on the upper surface of the substrate 31. The substrate 31 is formed using, for example, silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), aluminum nitride (AlN), sapphire (Si2O3), silicon carbide (SiC), or diamond.
[0012] Figure 2A shows a schematic configuration of the sensor unit 20. The sensor unit 20 is a circuit that changes the output voltage according to the magnetic flux density and includes multiple (four in this example) magnetoelectric conversion elements 21, 22, 23, and 24 arranged in a Wheatstone ridge (full bridge) circuit. Alternatively, two magnetoelectric conversion elements 21 and 23 or 22 and 24 may be used to arrange them in a half-bridge circuit.
[0013] Multiple magnetoelectric elements 21, 22, 23, and 24 are elements whose electrical characteristics (i.e., magnetoresistance) change depending on the strength of the applied magnetic field. The magnetoelectric elements 21, 22, 23, and 24 are arranged with their respective magnetic sensing directions oriented horizontally to detect the horizontal magnetic field generated on the conductor 40 when the current to be measured flows in the conductor 40 in the direction of the arrow. However, the magnetic sensing directions of magnetoelectric elements 21 and 24 are the same direction, and the magnetic sensing directions of magnetoelectric elements 22 and 23 are the same direction and opposite to the magnetic sensing directions of magnetoelectric elements 21 and 24. The multiple magnetoelectric elements 21, 22, 23, and 24 can be tunnel magnetoresistance elements (TMR), giant magnetoresistance elements (GMR), or anisotropic magnetoresistance elements (AMR). These elements are alloys containing at least one of Co, Fe, B, Ni, and Si, and more specifically, cobalt iron (CoFe), cobalt iron boron (CoFeB), and nickel iron (NiFe) can be used. By using these elements, the magnetic field generated by the flow of current through the conductor 40 can be precisely measured.
[0014] The output voltage V is the differential voltage between terminal 25 between magnetoelectric conversion elements 21 and 23 and terminal 26 between magnetoelectric conversion elements 22 and 24. V∝R1×R4-R2×R3 holds true, where R1, R2, R3, and R4 are the respective magnetoresists of magnetoelectric conversion elements 21, 22, 23, and 24. As a result, the magnetic sensor 30 can measure the strength of the magnetic field generated by the current being measured flowing through the conductor 40.
[0015] The two sensor units 20 are located on the first body portion 42a (a first main body portion 42a1 connected to the first terminal portion 41a and a first connection portion 42a2 connected to one end of the turn portion 43) and the second body portion 42b (a second main body portion 42b1 connected to the second terminal portion 41b and a second connection portion 42b2 connected to the other end of the turn portion 43). As will be described later, these connection portions have a rectangular shape when viewed from above, and by placing the sensor units 20 on them, the lateral magnetic field generated by energizing the conductor 40 is concentrated on the sensor units 20, making it possible to detect the amount of current with high sensitivity. The sensor unit 20 may be located on only one of the first connection portion 42a2 and the second connection portion 42b2. The first connection portion 42a2 and the second connection portion 42b2 may have a rectangular or substantially rectangular shape when viewed from above.
[0016] Figure 2B shows the definition of rectangularity, which represents the degree of rectangularity of the first connecting portion 42a2 and the second connecting portion 42b2. Assume that the contour lines of the first connecting portion 42a2 and the second connecting portion 42b2 are represented by solid lines. The rectangularity is defined as Sin / Sout, where Sin is the area of the largest rectangular region located inside the contour lines of the first connecting portion 42a2 and the second connecting portion 42b2, and Sout is the area of the smallest rectangular region located outside the contour lines of the first connecting portion 42a2 and the second connecting portion 42b2, with two parallel sides extending horizontally and two parallel sides extending vertically forming the rectangle. A truly rectangular shape has a rectangularity of 1, and a nearly rectangular shape has a rectangularity of 0.8 or more and less than 1. By allowing the first connecting portion 42a2 and the second connecting portion 42b2 to be substantially rectangular in shape, rather than being rectangular in top view, the molding of the lead frame during the manufacturing of the conductor 40 becomes easier, and the conductor 40 can adhere more closely to the package 10, preventing delamination between them.
[0017] The sensor unit 20 may be configured using a Hall element, and may be placed inside the turn unit 43 or near the conductor 40 to detect the vertical magnetic field generated when current flows through the conductor 40.
[0018] The conductor (also called a busbar) 40 is a conductive member positioned on one side (the lower side in the diagram) in the vertical direction within the package 10, forming a current path through which the current to be measured flows. It has a first terminal portion 41a, a second terminal portion 41b, a first body portion 42a, a second body portion 42b, and a turn portion 43. The thickness of the conductor 40 is approximately constant.
[0019] The first terminal section 41a is a terminal for inputting the current to be measured (also referred to simply as current). The first terminal section 41a is located on one side in the vertical direction (the lower side in the drawing) and protrudes from the lower side of the package 10 in the drawing.
[0020] The second terminal section 41b is a terminal for outputting current. The second terminal section 41b is positioned laterally (to the right in the drawing) away from the first terminal section 41a and protrudes from the lower side of the package 10 in the drawing. Alternatively, the second terminal section 41b may be used as a terminal for inputting current and the first terminal section 41a as a terminal for outputting current.
[0021] The first fuselage portion 42a is the portion that connects one end of the turn portion 43 to the first terminal portion 41a. The first fuselage portion 42a includes a first main body portion 42a1 and a first connecting portion 42a2 located on the first terminal portion 41a side and the turn portion 43 side, respectively. The first main body portion 42a1 has a tapered portion 42a3 that increases in cross-sectional area from the connecting portion with the turn portion 43 (first connecting portion 42a2) toward the first terminal portion 41a side, and at least one void 44a is located at the bottom of the tapered portion with the largest cross-sectional area (first terminal portion side) in the drawing. i The system includes a parallel section 44a in which (i=1~I, where I is 3 in this example) are arranged side by side in the lateral direction. The first connection section (also called the first arm section) 42a2 has a rectangular shape when viewed from above and connects to the turn section 43, on which the sensor section 20 of the magnetic sensor 30 is placed. The cross-sectional area of the tapered section 42a3 is the cross-sectional area of the section of the tapered section 42a3 that intersects perpendicularly with the inner contour surface 44a0 of the conductor 40.
[0022] The second fuselage section 42b is the part that connects the other end of the turn section 43 to the second terminal section 41b, and is positioned laterally (to the right in the drawing) away from the first fuselage section 42a. The second fuselage section 42b includes a second main body section 42b1 and a second connecting section 42b2 located on the second terminal section 41b side and the turn section 43 side, respectively. The second main body section 42b1 has a tapered section 42b3 that increases in cross-sectional area from the connecting section with the turn section 43 (second connecting section 42b2) toward the second terminal section 41b side, and at least one void 44b is located at the bottom of the tapered section with the largest cross-sectional area (towards the second terminal section) in the drawing. i The system includes a parallel section 44b in which (i=1~I, where I is 3 in this example) are arranged side by side in the lateral direction. The second connection section (also called the second arm section) 42b2 has a rectangular shape when viewed from above and connects to the turn section 43, on which the sensor section 20 of the magnetic sensor 30 is placed. The cross-sectional area of the tapered section 42b3 is the cross-sectional area of the tapered section 42b3 that intersects perpendicularly with the inner contour surface 44b0 of the conductor 40.
[0023] The turn section 43 is the part that connects to the two fuselage sections 42a and 42b at both ends. It is located on the other side in the vertical direction (upper side in the drawing), extends from one side in the vertical direction (lower side in the drawing) to the other side (upper side in the drawing), and has a shape that curves horizontally and returns to the one side. For example, it has a roughly arc shape. The turn section 43 may also be bent into a U-shape, an inverted V-shape, or a П-shape. The turn section 43 receives the current to be measured from the first fuselage section 42a and outputs the current to be measured to the second fuselage section 42b.
[0024] As described above, the conductor 40 includes the first terminal portion 41a, the second terminal portion 41b, the first body portion 42a, the second body portion 42b, and the turn portion 43, and has a substantially U-shape, extending from the first terminal portion 41a, located on the left side of the lower side of the package 10, through the interior of the package 10 back to the lower side, and to the second terminal portion 41b, located on the right side of the lower side. The conductor 40 can be formed using a conductive metal such as copper.
[0025] The multiple signal terminals 50 are components for transmitting the output signal of the magnetic sensor 30 to the secondary circuit 3. They are spaced apart from the conductor 40 on the upper side of the diagram, arranged laterally, and their tips are exposed from the upper side of the diagram and sealed within the package 10. The multiple signal terminals 50 can be formed using a conductive metal such as copper. The multiple signal terminals 50 are wire-bonded to the magnetic sensor 30. The tips exposed from the package 10 are connected to the secondary circuit 3 on the mounting substrate 100 when the current sensor 1 is mounted on the mounting substrate 100.
[0026] Because the conductor 40 has a small electrical resistance, Joule heat is generated when current flows through it. When a momentary overcurrent (called a surge current), such as one that occurs during a fault, flows through the conductor 40, the surge current contains high-frequency components of, for example, 1 MHz or higher, and due to the skin effect, the current density concentrates on the surface of the conductor 40. Furthermore, when current flows in opposite directions between adjacent conductors, such as the first body section 42a and the second body section 42b, the current density concentrates on the side closer to each other due to the proximity effect.
[0027] Figure 3A shows the definition of the shape and size (width w of the conductor 140 and the width w_space of the internal region) of the conductor 140 for simulation. The conductor 140 has two arm sections 142a and 142b and a turn section 143. The two arm sections 142a and 142b are rectangular portions where the sensor section 20 of the magnetic sensor 30 is located, and simulate the first body section 42a and the second body section 42b of the conductor 40. The turn section 143 is the part that connects the two arm sections 142a and 142b, and simulates the turn section 43 of the conductor 40. The width w of the conductor 140, i.e., the arm section 142b, is defined as w_space, which is half the distance between the opposing inner surfaces of the arm sections 142a and 142b (equal to the inner radius of curvature of the turn section 143). Assuming that the sensor unit 20 is positioned in the vertical center of the arm unit 142b, the current density field in this central portion was determined by harmonic analysis using the finite element method.
[0028] Figure 3B shows the analysis results of the surge current density distribution flowing through conductor 140. Here, the surge current was simulated with a harmonic current of frequency 1 MHz, and the material of conductor 140 was copper, with a plate thickness of 0.552 mm, and the width w = 1.5 mm of arm portion 142b. When the distance w_space = 10 mm, it can be seen that the current flowing through arm portion 142b is concentrated on the inner and outer surfaces of arm portion 142b due to the skin effect, and hardly flows in the center in the width direction. Here, there is not much difference in current density between the inner and outer surfaces of arm portion 142b. Similarly, at a distance w_space = 5 mm, the current flowing through arm portion 142b is concentrated on the inner and outer surfaces of arm portion 142b due to the skin effect, and hardly flows in the center in the width direction. There is not much difference in current density between the inner and outer surfaces of arm portion 142b. However, at distances w_space = 2.5 mm or less, the current flowing through the arm portion 142b is concentrated on the inner surface of the arm portion 142b due to the proximity effect, and the current density on the inner surface is significantly higher than that on the outer surface of the arm portion 142b. At distances w_space = 0.1 mm, the current density on the inner surface of the arm portion 142b is approximately nine times that of the outer surface. By bringing the two arm portions 142a and 142b closer together, especially at distances w_space = 2.5 mm or less, the surge current can be concentrated on the inner surface of the conductor 140 due to the proximity effect.
[0029] Figure 3C shows the analysis results of the amount of heat generated (average Joule heat of the cross-section) due to surge current flowing through the conductor 140, relative to the width w of the conductor 140. The amount of heat generated is calculated using the current density j in the conductor 140 and the cross-sectional area S of the conductor 140, and the amount of heat generated per unit cross-sectional area is ∫j. 2 The calculation was performed in dS / S. Here, the surge current frequency was assumed to be 1 MHz, the conductor 140 was made of copper, with a plate thickness of 0.552 mm and a distance w_space of 0.25 mm. The amount of heat generated by conductor 140 is greater the smaller the width w of conductor 140 is. Therefore, by reducing the width w of conductor 140, the heat generation within conductor 140 can be locally increased.
[0030] Figure 4A shows the definition of the shape and size of the conductor 140 for simulation (width w of the conductor 140, width w_space of the internal region, and position w_inner of the void). The conductor 140 has two arm sections 142a and 142b and a turn section 143. The two arm sections 142a and 142b are rectangular portions where the sensor section 20 of the magnetic sensor 30 is located, and simulate the first body section 42a and the second body section 42b of the conductor 40. The turn section 143 is the part that connects the two arm sections 142a and 142b, and simulates the turn section 43 of the conductor 40. The width w of the conductor 140, i.e., the arm section 142b, and w_space are defined as half the distance between the opposing inner surfaces of the arm sections 142a and 142b (equal to the inner radius of curvature of the turn section 143). A circular void 144b1 was placed in the vertical center of the arm portion 142b, and the distance from the inner surface of the arm portion 142b to the void 144b1 was defined as w_inner. The amount of heat generated in this central portion was analyzed using the finite element method.
[0031] Figure 4B shows the analysis results of the amount of heat generated by surge current flowing through conductor 140 (average Joule heat of the cross-section) at position w_inner of the void 144b1 in conductor 140. The amount of heat generated is calculated using the current density j in conductor 140 and the cross-sectional area S of conductor 140, and the amount of heat generated per unit cross-sectional area is ∫j. 2 The calculation was performed in dS / S. Here, the surge current frequency was 1 MHz, the material of conductor 140 was copper, the plate thickness was 0.552 mm, the width w of arm portion 42b was 4.4 mm, the distance w_space was 0.25 mm, and the void 144b1 was a circular shape with a diameter of 0.6 mm. The amount of heat generated in conductor 140 is greater the smaller the position w_inner of void 144b1. Therefore, for a given width w of conductor 140, by bringing the void 144b1 closer to the inner surface of arm portion 142b, the current distribution within conductor 140 can be further localized to the inner side, thereby further increasing the heat generated within conductor 140.
[0032] Therefore, in the current sensor 1 according to this embodiment, in a top view, the inner contour surfaces (i.e., inner surfaces) 44a0, 44b0 of the conductor 40 intersect perpendicularly with a continuous cross section of the conductor 40, and the inner contour surfaces 44a0, 44b0 of the conductor 40 within the parallel section 44a, 44b, and at least one void 44a i ,44b i Assume that the cross-sectional area S1 of a continuous section between the inner surfaces of the voids 44a1, 44b1 located on the innermost contour surfaces 44a0, 44b0 side of the conductor 40 (i=1~I, where I is 1 or greater) and the conductor 40 is smaller than the cross-sectional area S43 of another continuous section between the inner contour surfaces 44a0, 44b0 of the conductor 40 outside the parallel sections 44a, 44b and the outer contour surfaces (i.e., outer surfaces) 44a5, 44b5 of the conductor 40, for example, the cross-sectional area S43 of the turn section 43. As a result, when a surge current (a sudden large current) flows through the conductor 40, the proximity effect causes the current to concentrate in the continuous section S1 within the parallel sections 44a, 44b, generating heat and melting, thus performing a fuse function. Since cross section S1 is located at a distance from the first terminal section 41a, the second terminal section 41b, and the turn section 43, damage to the primary circuit located on one side (lower side in the drawing) of the first terminal section 41a and the second terminal section 41b in the vertical direction, and damage to the secondary circuit located on the other side (upper side in the drawing) of the turn section 43 in the vertical direction, can be prevented.
[0033] Figure 5A shows the surge current that flows concentrated inside the conductor 40 due to the proximity effect. Based on the analysis results described above, the distance between the contour surfaces of the first body section 42a and the second body section 42b, which face each other, is set to 5 mm or less. As a result, the surge current enters the conductor 40 from the first terminal section 41a, concentrates near the inner surface of the first body section 42a (the right-hand side in the drawing), flows upward in the drawing, changes direction via the vicinity of the inner surface of the turn section 43, concentrates near the inner surface of the second body section 42a (the left-hand side in the drawing), flows downward in the drawing, and is output from the second terminal section 41b. In this way, the proximity effect localizes the flow of the surge current in a narrow region near the inner surfaces of the first body section 42a and the second body section 42b, and heat generation can be increased only in that localized region.
[0034] Furthermore, by bringing the holes 44a1 and 44b1 in the parallel sections 44a and 44b closer to the inner surfaces of the first body part 42a and the second body part 42b respectively (for example, setting w_inner to 0.5 mm or less), the flow of the surge current can be further localized in the narrow regions near the inner surfaces of the first body part 42a and the second body part 42b within the parallel sections 44a and 44b, and heat generation can be further increased in the localized regions. As a result, the parallel section 44a of the first body part 42a and / or the parallel section 44b of the second body part 42b can perform a fuse function, and it becomes possible to prevent damage to the primary side circuit and the secondary side circuit.
[0035] Therefore, in the current sensor 1 according to the present embodiment, in a top view, it intersects perpendicularly with the inner contour surfaces 44a0 and 44b0 of the conductor 40 outside the parallel sections 44a and 44b, and as a continuous cross-section between the inner contour surfaces 44a0 and 44b0 of the conductor 40 inside the parallel sections 44a and 44b and the outer contour surfaces 44a5 and 44b5 of the conductor 40, it lies on a single plane that intersects perpendicularly with the inner contour surfaces 44a0 and 44b0 of the conductor 40, and the inner contour surfaces 44a0 and 44b0, at least one hole 44a i ,44b i (i = 1 to I, where I is 3 in this example), and there is assumed to be a continuous cross-section having a cross-sectional area (S43 < S1 + S2 + S3 + S4) smaller than the total cross-sectional area S1 + S2 + S3 + S4 of the plurality of cross-sections defined by the inner surfaces and the outer contour surfaces 44a5 and 44b5. The continuous cross-section is, for example, the cross-sectional area S43 of the turn portion 43.
[0036] FIG. 5B shows the DC current flowing over the entire conductor 40. Regarding the DC current, since the proximity effect hardly contributes, the DC current in the measured current input from the first terminal portion 41a spreads over the entire first body part 42a, and passes through the cross-sections S1 to S4 between the holes 44a i (i = 1 to 3) to flow through the conductor 40, enters the second body part 42b through the turn portion 43, spreads over the entire second body part 42b, and the holes 44b iThe current flows through the conductor 40 via the cross sections S1 to S4 between (i=1 to 3) and is output from the second terminal section 41b. Because the total cross-sectional area S1+S2+S3+S4 of the multiple cross-sections in the parallel sections 44a and 44b is greater than the cross-sectional area S43 of the turn section 43, the high-frequency component (see Figure 5A) and the DC component (see Figure 5B) of the current being measured are frequency-separated, and a current sensor 1 that achieves both low resistance to DC current can be provided.
[0037] Furthermore, in a top view, the cross-sectional area S43 of the turn portion 43 intersects perpendicularly with the inner contour surfaces 44a0, 44b0 of the conductor 40 outside the parallel sections 44a, 44b, and is a continuous cross section between the inner contour surfaces 44a0, 44b0 of the conductor 40 and the outer contour surfaces 44a5, 44b5 of the conductor 40, for example, the cross-sectional area S43 of the turn portion 43 is such that the inner contour surfaces 44a0, 44b0 of the conductor 40 within the parallel sections 44a, 44b and the outer contour surfaces 44a5, 44b5 of the conductor 40 have at least one void 44a i ,44b i The cross-sectional area of each of the multiple cross-sections demarcated by the inner and outer contour surfaces 44a5 and 44b5 of (i=1~3) is larger than the respective cross-sectional areas S1, S2, S3, or S4.
[0038] Figures 6A and 6B show the fuse operation of conductor 40. The void 44a within the parallel sections 44a and 44b. i ,44b iBecause the cross-sections S1 to S4 between (i=1 to 3) are smaller than the cross-sections outside the parallel sections 44a and 44b, when an excessive surge current flows through the conductor 40, the current concentrates in cross-section S1 within the parallel section 44a due to the proximity effect (see Figure 5A), generating heat and causing the conductor 40 to melt in cross-section S1 within the parallel section 44a, as shown in Figure 6A. As a result, a slit is formed in the conductor 40 extending from the inner contour surface 44a0 of the conductor 40 within the parallel section 44a to the void 44a1. The surge current concentrates near both inner surfaces of the slit due to the proximity effect, generating further heat and causing the conductor 40 to melt in the next cross-section S2 within the parallel section 44a, as shown in Figure 6B. As a result, a slit is formed in the conductor 40 extending from the inner contour surface 44a0 of the conductor 40 within the parallel section 44a to the void 44a2. The surge current concentrates near both inner surfaces of the slit due to the proximity effect, generating further heat and discharging from the voids 44a aligned within the parallel section 44a. i The cross sections between (i=1~3) are melted sequentially in the direction of the arrows, and finally, in the parallel section 44a, the first fuselage section 42a is cut in two in the vertical direction. In this way, within the parallel section, 44a i The arrangement of (i=1~3) induces the melting of the conductor 40 in the lateral direction, preventing the melting from progressing toward the primary circuit located on one side in the vertical direction of the first terminal portion 41a and the second terminal portion 41b (lower side in the drawing) or toward the secondary circuit located on the other side in the vertical direction of the turn portion 43 (upper side in the drawing).
[0039] Figure 7A shows the definitions of the shape and size of the conductor 140 for simulation (width w of the conductor 140, width w_space of the internal region, position w_inner of the void, width w_slit). The conductor 140 has two arm sections 142a and 142b and a turn section 143. The two arm sections 142a and 142b are rectangular portions where the sensor section 20 of the magnetic sensor 30 is located, and simulate the first body section 42a and the second body section 42b of the conductor 40. The turn section 143 is the part that connects the two arm sections 142a and 142b, and simulates the turn section 43 of the conductor 40. The width w of the conductor 140, i.e., the arm section 142b, is defined as w_space, which is half the distance between the opposing inner surfaces of the arm sections 142a and 142b (equal to the inner radius of curvature of the turn section 143). Two circular holes 144b2 and 144b3 were placed in the vertical center of the arm portion 142b, and the width of the slit extending from the inner surface of the arm portion 142b to hole 144b2 was defined as w_slit. The amount of heat generated in this central portion was analyzed using the finite element method. Three circular holes 144a1 to 144a3 were placed in the vertical center of the arm portion 142a. The distance between holes 44b2 and 44b3 and between holes 44a1 to 44a3 was defined as w0.
[0040] Figure 7B shows the analysis results of the amount of heat generated by surge current flowing through the conductor (average Joule heat of the cross-section) for a given slit width w_slit in the conductor 140. The amount of heat generated is calculated using the current density j in the conductor 140 and the cross-sectional area S of the conductor 140, with ∫j being the amount of heat generated per unit cross-sectional area. 2 The calculation was performed in dS / S. Here, the surge current frequency was 1 MHz, the material of conductor 140 was copper, the plate thickness was 0.552 mm, the width w=4.4 mm and distance w_space=0.25 mm of arm section 142b, the voids 144b2 and 144b3 were circular with a diameter of 0.6 mm, and the distance between the voids w0=1.3 mm. The amount of heat generated by conductor 140 is greater as the slit width w_slit decreases.
[0041] Therefore, void 44a i ,44b i(i=1~I, I is 3 in this example) has a roughly circular, roughly elliptical, or roughly rectangular shape when viewed from above, and its vertical width is 5 mm or less, preferably 2 mm, more preferably 1 mm, and even more preferably 0.6 mm or less, 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less. Note that void 44a i ,44b i The vertical width of (i=1~I, where I is 3 in this example) is preferably greater than or equal to the thickness of the conductor 40 in order to ensure the processability of the conductor 40. Here, the thickness of the conductor 40 is, for example, 1 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.
[0042] Here, void 44a i ,44b i The conductors (i=1~I, I is 3 in this example) do not need to be arranged in a straight line in the horizontal direction, but may be arranged so that at least a portion of each faces each other in the horizontal direction, that is, so that their regions partially overlap when viewed horizontally. Alternatively, if the melting of the conductor 40 as a whole progresses horizontally, they may be arranged, for example, in a staggered pattern. In this way, in the slit portions formed by the melting of the conductor 40 in the cross-section within the parallel sections 44a and 44b, the surge current is further concentrated near the inner surface of the slit due to the proximity effect, creating voids 44a within the parallel sections 44a and 44b. i ,44b i The conductor 40 can be fused in the lateral direction where (i=1~I, where I is 3 in this example) is arranged.
[0043] Note that the void 44a i ,44b iThe number I (i=1~I) and the distances between them can be arbitrarily determined as long as the cutting of the conductor 40 proceeds in a lateral direction as a whole. However, it is desirable that the distances increase in the following order within the parallel sections 44a, 44b: the distance from the inner contour surfaces 44a0, 44b0 of the conductor 40 to the void 44a1, the distance between the voids 44a1, 44a2, the distance between the voids 44a2, 44a3, and the distance between the void 44a3 and the outer contour surfaces 44a5, 44b5 of the conductor 40 (i.e., cross-sectional area S1 ≤ S2 ≤ S3 ≤ S4). This allows the cutting of the conductor 40 within the parallel sections 44a, 44b to proceed from the inner contour surfaces 44a0, 44b0 to the outer contour surfaces 44a5, 44b5 of the conductor 40.
[0044] Figure 8 shows a top view of the internal configuration of the current sensor 1 equipped with a fault detection function. The magnetic sensor 30 further includes a thermometer 32 positioned on the substrate 31, spaced apart from each of the two sensor units 20, and an electronic circuit 33 that receives the temperature measurement results from the two sensor units 20 and the thermometer 32. In this example, the thermometer 32 is positioned in the center of the two sensor units 20. Here, the substrate 31 is positioned over at least a portion of the turn portion 43, the first connection portion 42a2, and the second connection portion 42b2 of the conductor 40. The distances from the parallel sections 44a and 44b to the two sensor units 20 and the thermometer 32 are different. Here, the two sensor units 20 can also be used as a thermometer by utilizing, for example, the temperature characteristics of the resistance value of the magnetoelectric conversion element.
[0045] The electronic circuit 33 independently monitors the temperature using the two sensor units 20 and the thermometer 32, and when the temperature difference between the two sensor units 20 and the thermometer 32 exceeds a threshold, it sends a signal to the secondary circuit 3 via, for example, multiple signal terminals 50. Under normal circumstances, the temperature inside the current sensor 1 is determined by the external temperature and the heat generated by the current being measured (DC component or low-frequency component) flowing through the conductor. The temperature gradient inside the package 10 caused by these is small. However, when a surge current flows through the conductor 40, the fuse function is activated, and for example, the cross section (e.g., cross section S1) in the parallel section 44a melts, forming a slit extending from the inner surface 44a0 of the conductor 40 to the void 44a1. Then, the surge current concentrates at the cross section P2 between the voids 44a1 and 44a2 within the parallel section 44a, generating heat, which causes the temperature gradient inside the package 10 to increase rapidly. Here, because the parallel section 44a, particularly the distance from cross-section P2, is different for the two sensor units 20 and the thermometer 32, a difference in the measured temperature occurs due to the temperature gradient. When this temperature difference exceeds a predetermined threshold temperature, it can be determined that the fuse function has been activated. Since the melting of the conductor 40 proceeds on the order of, for example, 10 milliseconds, the electronic circuit 33 can detect the activation of the fuse function by detecting the difference in measured temperatures between the two sensor units 20 and the thermometer 32, thereby detecting a sensor malfunction.
[0046] Furthermore, if multiple sensor units 20 are provided on the substrate 31, the thermometer 32 does not need to be provided. However, the two sensor units 20 are arranged on the substrate 31 at different distances from the parallel sections 44a and 44b. The electronic circuit 33 can independently monitor the temperature of the two sensor units 20 and transmit a signal when the temperature difference between at least two sensor units 20 exceeds a threshold.
[0047] Figure 9 shows the arrangement of the conductor 40, insulating layer 39, and magnetic sensor 30 in a top view. The insulating layer 39 is a component that insulates and protects the magnetic sensor 30 from the conductor 40 and is disposed between the conductor 40 and the magnetic sensor 30. The insulating layer 39 may contain either an organic layer or a ceramic. The insulating layer 39 can be formed using, for example, polyimide, glass, paper, fluororesin (Teflon®), or silicon. The magnetic sensor 30 is placed on the conductor 40 via the insulating layer 39, and in a top view, the contour line of the insulating layer 39 is located outside the contour line of the substrate 31. To ensure insulation, it is preferable that the contour line of the insulating layer 39 is at least 0.4 mm away from the contour line of the substrate 31. This effectively insulates the magnetic sensor 30 from the conductor 40 without the insulating layer 39 covering the entire top surface of the conductor 40, and the insulating layer 39 does not hinder the heat dissipation of the conductor 40 or reduce the heat dissipation performance of the conductor 40.
[0048] Furthermore, in a top view, the contour line of the insulating layer 39 is located on the turn section 43 side when viewed from the parallel sections 44a and 44b; that is, the insulating layer 39 is positioned closer to the turn section 43 than to the parallel sections 44a and 44b. The ignition point of the polyimide or other material forming the insulating layer 39 is approximately 600°C, which is lower than the melting point (approximately 1000°C) of the copper or other metal forming the conductor 40. Therefore, by separating the insulating layer 39 from the parallel sections 44a and 44b that activate the fuse function, the current sensor 1 can be designed safely.
[0049] Figure 10A shows a top view of the configuration of the mounting board 100 on which the current sensor 1 is mounted. The mounting board 100 is a board that includes the current sensor 1, a primary circuit 2, and a secondary circuit 3. On the mounting board 100, the current to be measured is input from the primary circuit 2 to the current sensor 1, and the output signal of the current sensor 1 is output to the secondary circuit 3 via a plurality of signal terminals 50. The current sensor 1 is configured as described above.
[0050] The primary circuit 2 is a circuit that inputs the current to be measured to the current sensor 1, and is connected to the first terminal portion 41a and the second terminal portion 41b of the conductor 40 of the current sensor 1.
[0051] The secondary circuit 3 is a circuit that operates in response to the output signal of the current sensor 1 and comprises multiple footprints 70, each connected to a plurality of circuits (not shown). Each of the multiple footprints 70 is connected to a plurality of signal terminals 50 (see Figure 10B), and the output signal of the current sensor 1 is transmitted to each of the plurality of circuits via the plurality of signal terminals 50. The plurality of footprints 70 includes footprint 71 connected to one of the signal terminals 50, signal terminal 51, and footprints 72 connected to seven signal terminals 52.
[0052] Figure 10B shows the arrangement of the current sensor 1 and the multiple footprints 70 in a top view. As previously mentioned, one signal terminal 51 and seven signal terminals 52 of the multiple signal terminals 50 are connected to one footprint 71 and seven footprints 72 of the multiple footprints 70, respectively. Here, one signal terminal 51 of the multiple signal terminals 50 is closer to the turn portion 43 than the other signal terminals 52. The distance L51 from signal terminal 51 to the turn portion 43 is smaller than the distance L52 from the other signal terminals 52 to the turn portion 43. This allows the heat generated in the turn portion 43 to be dissipated to the outside of the package 10 via the signal terminal 51 that is closest to the turn portion 43 among the multiple signal terminals 50. It is preferable that the distance L51 from signal terminal 51 to the turn portion 43 be 0.4 mm or more in order to ensure insulation between the conductor 40 and the secondary circuit 3.
[0053] Note that signal terminal 51 may be a GND terminal. By having the signal terminal 51 closest to the turn section 43 be a GND terminal, if an arc discharge occurs in the turn section 43, the discharge can be induced from the adjacent signal terminal 51 to GND, thereby suppressing damage to multiple circuits on the secondary circuit 3 to which the other signal terminals 52 are connected.
[0054] Furthermore, when the current sensor 1 is mounted on the mounting board 100, the signal terminal 51 is connected to a footprint 71 on the mounting board 100 that has a larger area than the footprint 72 to which the other signal terminals 52 are connected. As a result, the footprint 71 on the mounting board 100 to which the signal terminal 51 is connected has a larger area than the footprint 72 to which the other signal terminals 52 are connected, allowing the signal terminal 51, which is heated by heat transfer from the turn section 43, to have a larger heat dissipation area and dissipate heat efficiently, thereby improving the heat dissipation of the turn section 43 and preventing failure due to heat accumulation. Preferably, the footprint 71 has an area 1.5 to 40 times larger than the other footprints 72. In this way, heat dissipation of the turn section 43 is enhanced, and the activation of the fuse function of the conductor 40 in the parallel sections 44a and 44b can be increased.
[0055] As described above, the current sensor 1 according to this embodiment includes a conductor 40 having a first terminal portion 41a for inputting current, which is arranged on one side in the first axis direction, a second terminal portion 41b for outputting current that is separated from the first terminal portion 41a in the second axis direction intersecting the first axis direction, a turn portion 43 arranged on the other side in the first axis direction relative to the first terminal portion 41a, a first body portion 42a connecting one end of the turn portion 43 to the first terminal portion 41a, and a second body portion 42b separated from the first body portion 42a in the second axis direction and connecting the other end of the turn portion 43 to the second terminal portion 41b, a magnetic sensor 30 arranged on or near the conductor 40, the turn portion 43 of the conductor 40, the first body portion 42a, the second body portion 42b, and the magnetic sensor 30 are sealed, The package 10 has a first terminal portion 41a and a second terminal portion 41b exposed, and at least one of the first body portion 42a and the second body portion 42b includes parallel sections 44a, 44b having at least one void, and when viewed from a third direction intersecting the first axial direction and the second axial direction, the cross-sectional area S1 of a continuous section of the conductor 40 that intersects perpendicularly with the inner contour surface of the conductor 40 is smaller than the cross-sectional area of other continuous sections between the inner contour surface of the conductor 40 outside the parallel sections 44a, 44b and the outer contour surface of the void 44a1, 44b1 located on the innermost contour surface side of the conductor.
[0056] According to this, in a top view, in a continuous cross section of the conductor 40 that intersects perpendicularly with the inner contour surfaces 44a0, 44b0 of the conductor 40, at least one void 44a is in at least one of the first body portion 42a and the second body portion 42b. i ,44b i Within the parallel sections 44a, 44b provided with (i=1~3), the inner contour surfaces 44a0, 44b0 of the conductor 40 and at least one void 44a i ,44b iThe cross-sectional area S1 of the continuous section partitioned between the inner surface of the void 44a1, 44b1 located on the innermost contour surface 44a0, 44b0 side of the conductor among (i=1~3) and the outer contour surface 44a5, 44b5 of the conductor 40 is smaller than the cross-sectional area of the other continuous section between the inner contour surface 44a0, 44b0 of the conductor 40 outside the parallel section 44a, 44b and the outer contour surface 44a5, 44b5 of the conductor 40. As a result, when a surge current (a sudden large current) flows through the conductor 40, the current concentrates in the continuous section S1 within the parallel section 44a, 44b, generating heat and melting, thus acting as a fuse. This separates the primary circuit located on one side in the vertical direction of the first terminal section 41a and the second terminal section 41b (lower side in the drawing) from the secondary circuit located on the other side in the vertical direction of the turn section 43 (upper side in the drawing), thereby providing a high-voltage current sensor 1.
[0057] Furthermore, in the current sensor 1 according to this embodiment, the thickness of the conductor 40 is approximately constant. When viewed from a third direction intersecting the first and second axial directions, the dimensions (i.e., width) of the cross-section in the parallel sections 44a and 44b are smaller than the dimensions of the cross-section in the portion of the conductor 40 outside the parallel sections 44a and 44b. The dimensions of the cross-section in the portion of the conductor 40 outside the parallel sections 44a and 44b are smaller than the sum of the dimensions of the multiple cross-sections in the parallel sections 44a and 44b when a straight line is drawn perpendicular to the contour line from the inner contour line of the conductor 40 to the outer contour line of the conductor 40.
[0058] Figures 11A to 11F show the configurations of modified current sensors 1A, 1B, 1C, 1D, 1E, and 1F in a top view.
[0059] Figure 11A shows the configuration of the current sensor 1A according to the first modified example. Compared to the current sensor 1 shown in Figure 1, the two sensor parts 20 of the magnetic sensor 30 are positioned closer to each other than to the center of the conductor 40. This makes it possible to suppress the generation of common-mode voltage due to the non-uniformity of the magnetic field distribution around the conductor 40.
[0060] Figure 11B shows the configuration of the current sensor 1B according to the second modified example. Compared to the current sensor 1 shown in Figure 1, the vertical length of the first connection portion 42a2 and the second connection portion 42b2 of the conductor 40 is shorter, for example, to half, preferably one-fifth, more preferably one-tenth, even more preferably one-hundredth, and even more preferably one-thousandth of the vertical width of the magnetic sensor 30 (substrate 31), thereby reducing the resistance of the conductor 40 and suppressing heat generation due to DC current.
[0061] Figure 11C shows the configuration of the current sensor 1C according to the third modified example. Compared to the current sensor 1 shown in Figure 1, the voids 44a arranged within the parallel sections 44a, 44b of the conductor 40 i ,44b i The shape of (i=1~3) is not limited to a circular shape (or a nearly circular shape), but may also be a polygon including an ellipse (or a nearly ellipse) or a rectangle (or a nearly rectangular shape).
[0062] Figure 11D shows the configuration of a current sensor 1D according to a fourth modified example. Compared to the current sensor 1 shown in Figure 1, the turn portion 43, the first connection portion 42a2, and the second connection portion 42b2 of the conductor 40 may be formed in a U-shape. This makes it easier to process the conductor 40 and also simplifies the design of the signal terminal 50.
[0063] Figure 11E shows the configuration of a current sensor 1E according to a fifth modified example. Compared to the current sensor 1 shown in Figure 1, the turn portion 43 of the conductor 40 may be formed in an inverted V shape. This allows for a more compact design of the turn portion 43.
[0064] Figure 11F shows the configuration of the current sensor 1F according to the sixth modified example. Compared to the current sensor 1 shown in Figure 1, the turn portion 43, the first connection portion 42a2, and the second connection portion 42b2 of the conductor 40 may be formed in a P-shape. This makes it possible to increase the top viewing area of the turn portion 43 and improve the heat dissipation of the turn portion 43.
[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] 1, 1A, 1B, 1C, 1D, 1E, 1F…Current sensor, 2…Primary circuit, 3…Secondary circuit, 10…Package, 20…Sensor section, 21, 22, 23, 24…Magnetoelectric conversion element, 25, 26…Terminals, 30…Magnetic sensor, 31…Circuit board, 32…Thermometer, 33…Electronic circuit, 39…Insulating layer, 40…Conductor, 41a…First terminal section, 41b…Second terminal section, 42a (42a1, 42a2)…First body section (First main body section, First connection section (arm section)), 42b (42b1 ,42b2)...Second body section (second main body section, second connection section (arm section)), 43...Turn section, 44a,44b...Parallel section, 44a0,44b0...Contour surface (inner surface), 44a1~44a3,44b1~44b3...Vacuum, 44a5,44b5...Contour surface (outer surface), 50,51,52...Signal terminals, 70,71,72...Footprint, 100...Mounted board, 140...Conductor, 142a,142b...Arm section, 143...Turn section, P2,S1~S4,S43...Cross section.
Claims
1. A conductor having a first terminal portion for inputting current, which is arranged on one side in the first axial direction; a second terminal portion for outputting current, which is separated from the first terminal portion in the second axial direction intersecting the first axial direction; a turn portion arranged on the other side in the first axial direction relative to the first terminal portion; a first body portion connecting one end of the turn portion to the first terminal portion; and a second body portion separated from the first body portion in the second axial direction, which connects the other end of the turn portion to the second terminal portion. A magnetic sensor disposed on or near the conductor, The package comprises the turn portion of the conductor, the first body portion, the second body portion, and the magnetic sensor, and the first terminal portion and the second terminal portion, At least one of the first fuselage section and the second fuselage section includes a parallel section having at least one void, Viewed from a third direction intersecting the first and second axial directions, the cross-sectional area of a first continuous cross-section of the conductor that intersects perpendicularly with the inner contour surface of the conductor, and is defined between the inner contour surface of the conductor within the parallel section and the inner surface of the at least one void located closest to the inner contour surface of the conductor, is smaller than the cross-sectional area of the other continuous cross-section between the inner contour surface of the conductor outside the parallel section and the outer contour surface of the conductor. Current sensor.
2. The current sensor according to claim 1, wherein, when viewed from the third direction, there exists a second continuous cross-section that intersects perpendicularly with the inner contour surface of the conductor outside the parallel section, and among the continuous cross-sections from the inner contour surface of the conductor to the outer contour surface of the conductor, there exists a second continuous cross-section that lies on a plane that intersects perpendicularly with the inner contour surface of the conductor between the inner contour surface of the conductor and the outer contour surface of the conductor within the parallel section, and has a cross-sectional area smaller than the sum of the cross-sectional areas of the plurality of cross-sections demarcated by the inner contour surface, the inner surface of the at least one void, and the outer contour surface.
3. The current sensor according to claim 1, wherein at least one of the first body portion and the second body portion has a tapered portion that increases the cross-sectional area of the cross section that intersects perpendicularly with the inner contour surface of the conductor in the direction from the other side to the one side in the first axial direction, from the connection portion with the turn portion.
4. The first fuselage section has a first connecting portion that connects to the turn section, The second fuselage section has a second connecting section that connects to the turn section, At least one of the first connecting portion and the second connecting portion has a substantially rectangular shape when viewed from the third direction. The current sensor according to claim 1, wherein at least a portion of the magnetic sensor is disposed at at least one of the first connection portion and the second connection portion.
5. The current sensor according to claim 1, wherein the distance between the contour surfaces of the first and second body portions facing each other is 5 mm or less.
6. The current sensor according to claim 1, wherein, when viewed from the third direction, a continuous cross section between the inner contour surface of the conductor outside the parallel section and the outer contour surface of the conductor has a cross-sectional area greater than the cross-sectional area of each of the plurality of cross-sections partitioned between the inner contour surface of the conductor and the outer contour surface of the conductor within the parallel section by the inner contour surface, the inner surface of the at least one void, and the outer contour surface.
7. The current sensor according to claim 6, wherein the at least one void includes a plurality of voids arranged so that at least a portion of them faces each other in the second axial direction.
8. The current sensor according to claim 1, wherein the width of the at least one void in the first axial direction is 5 mm or less.
9. A substrate disposed on the conductor via an insulating layer, further comprising the substrate supporting the magnetic sensor, The substrate is arranged in at least a portion of the turn portion, the first connection portion, and the second connection portion. The substrate is provided with a thermometer located away from the magnetic sensor. The distances from the parallel section are different for the magnetic sensor and the thermometer. The current sensor according to claim 4.
10. The current sensor according to claim 9, wherein the substrate is provided with an electronic circuit that independently monitors the temperature with the magnetic sensor and the thermometer, and emits a signal when the temperature difference between the magnetic sensor and the thermometer exceeds a threshold.
11. A substrate disposed on the conductor via an insulating layer, further comprising the substrate supporting at least two of the magnetic sensors, The substrate is arranged in at least a portion of the turn portion, the first connection portion, and the second connection portion. The distances from the parallel section are different for at least two of the magnetic sensors. The current sensor according to claim 4.
12. The current sensor according to claim 11, wherein the substrate is provided with an electronic circuit that independently monitors the temperature with at least two of the magnetic sensors and emits a signal when the temperature difference between at least two of the magnetic sensors exceeds a threshold.
13. A substrate disposed on the conductor via an insulating layer, further comprising the substrate supporting the magnetic sensor, The substrate is arranged in at least a portion of the turn portion, the first connection portion, and the second connection portion. When viewed from the third direction, the contour line of the insulating layer is located outside the contour line of the substrate. The current sensor according to claim 4.
14. The current sensor according to claim 13, wherein the insulating layer includes either an organic layer or a ceramic layer.
15. The insulating layer comprises polyimide or fluororesin. The current sensor according to claim 14, wherein the contour line of the insulating layer, when viewed from the third direction, is located on the turn portion side when viewed from the parallel section.
16. The package further comprises a plurality of signal terminals that are separated from the conductor on one side in the first axial direction, with their tips exposed and sealed within the package. At least one of the plurality of signal terminals is closer to the turn section than the other signal terminals. The current sensor according to claim 1.
17. The current sensor according to claim 16, wherein the at least one signal terminal is a GND terminal.
18. The current sensor according to claim 16, wherein when the current sensor is mounted on a mounting board, at least one signal terminal is connected to a footprint on the mounting board that is larger in area than the footprint on the mounting board to which the other signal terminals among the plurality of signal terminals are connected.
19. The current sensor according to claim 1, wherein the thickness of the conductor is substantially constant.
20. A conductor having a first terminal portion for inputting current, which is arranged on one side in the first axial direction; a second terminal portion for outputting current, which is separated from the first terminal portion in the second axial direction intersecting the first axial direction; a turn portion arranged on the other side in the first axial direction relative to the first terminal portion; a first body portion connecting one end of the turn portion to the first terminal portion; and a second body portion separated from the first body portion in the second axial direction, which connects the other end of the turn portion to the second terminal portion. A magnetic sensor disposed on or near the conductor, The package comprises the turn portion of the conductor, the first body portion, the second body portion, and the magnetic sensor, and the first terminal portion and the second terminal portion, At least one of the first fuselage section and the second fuselage section includes a parallel section having at least one void, Viewed from a third direction intersecting the first and second axial directions, Regarding the cross-section of the conductor from the inner contour line to the point where a straight line drawn perpendicular to the contour line first intersects with another contour line of the conductor, the dimensions of the cross-section in the parallel section are smaller than the dimensions of the cross-section in the portion of the conductor outside the parallel section. A cross-section of the conductor obtained by drawing a straight line perpendicular to the inner contour line and extending it to the outer contour line, contains a cross-section in the portion of the conductor outside the parallel section that has dimensions smaller than the sum of the dimensions of the multiple cross-sections in the parallel section. Current sensor.