Current sensor

Abstract

The invention provides a current sensor which can easily detect faults. The current sensor includes: a conductor having a first terminal portion, a second terminal portion, a turning portion, a first main body portion, and a second main body portion; a magnetic sensor disposed on the conductor or in the vicinity of the conductor; and a package that seals the turning portion of the conductor, the first body portion, the second body portion, and the magnetic sensor, and exposes the first terminal portion and the second terminal portion. At least one of a cross-sectional area of a cross-section obtained by cutting the first terminal portion by the outer surface of the package and a cross-sectional area of a cross-section obtained by cutting the second terminal portion by the outer surface of the package is smaller than a cross-sectional area of the turning portion. A connection portion between the first body portion and the turning portion and a connection portion between the second body portion and the turning portion have a substantially rectangular shape in plan view, and the magnetic sensor is disposed on at least one of the connection portion between the first body portion and the turning portion and the connection portion between the second body portion and the turning portion.

Description

Technical Field

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

[0002] There is known a current sensor in which a conductor through which a current to be measured flows and a magnetoelectric conversion element close to the conductor are sealed in a package, and the magnetoelectric conversion element is used to detect the intensity of a magnetic field generated due to the current to be measured flowing through the conductor and convert it into an electric signal, thereby detecting the amount of current. In this current sensor, in order to concentrate the magnetic field on the magnetoelectric conversion element and improve the detection sensitivity, the cross-sectional area of the conductor portion close 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. Thus, in the case of an overcurrent flowing due to a failure or the like, the conductor inside the package overheats, which may cause a failure of the sensor. In Patent Document 1, there is disclosed a pyrotechnic circuit breaker that prevents damage to the sensor by discharging an arc discharge generated during an overcurrent at the time of a failure to the separator side. However, it is generally difficult to detect a failure occurring inside the package.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2017 / 136221 Summary of the Invention

[0006] Means for Solving the Problem

[0007] In one aspect of the present invention, there is provided a current sensor including: a conductor having a first terminal portion, a second terminal portion, a turning portion, a first main body portion, and a second main body portion, the first terminal portion being disposed on one side in a first axial direction and for inputting a current, the second terminal portion being separated from the first terminal portion in a second axial direction intersecting the first axial direction and for outputting the current, the turning portion being disposed on the other side in the first axial direction, the first main body portion connecting one end of the turning portion and the first terminal portion, and the second main body portion being separated from the first main body portion in the second axial direction and connecting the other end of the turning portion and the second terminal portion; a magnetic sensor disposed on or near the conductor; and a package that seals the turning portion, the first main body portion, the second main body portion, and the magnetic sensor of the conductor and exposes the first terminal portion and the second terminal portion, and at least one of the cross-sectional area of the connection portion between the first terminal portion and the first main body portion and the cross-sectional area of the connection portion between the second terminal portion and the second main body portion is smaller than the cross-sectional area of the turning portion.

[0008] In one aspect of the present invention, a current sensor is provided, which includes: a conductor having a first terminal portion, a second terminal portion, a turning portion, a first main body portion, and a second main body portion, wherein the first terminal portion is disposed on one side of a first axial direction and is configured to input a current, the second terminal portion is separated from the first terminal portion in a second axial direction intersecting the first axial direction and is configured to output the current, the turning portion is disposed on the other side of the first axial direction, the first main body portion connects one end of the turning portion and the first terminal portion, the second main body portion is separated from the first main body portion in the second axial direction and connects the other end of the turning portion and the second terminal portion; a magnetic sensor disposed on or near the conductor; and a package that seals the turning portion, the first main body portion, the second main body portion, and the magnetic sensor of the conductor and exposes the first terminal portion and the second terminal portion, and at least one of a cross-sectional area of a cross-section obtained by cutting the first terminal portion with an outer surface of the package and a cross-sectional area of a cross-section obtained by cutting the second terminal portion with the outer surface of the package is smaller than a cross-sectional area of the turning portion, a connecting portion between the first main body portion and the turning portion and a connecting portion between the second main body portion and the turning portion have a substantially rectangular shape in a plan view, and the magnetic sensor is disposed on at least one of the connecting portion between the first main body portion and the turning portion and the connecting portion between the second main body portion and the turning portion.

[0009] In one aspect of the present invention, a current sensor is provided, which includes: a conductor having a first terminal portion, a second terminal portion, a turning portion, a first main body portion, and a second main body portion, wherein the first terminal portion is disposed on one side in a first axial direction and is used for inputting a current, the second terminal portion is separated from the first terminal portion in a second axial direction intersecting the first axial direction and is used for outputting the current, the turning portion is disposed on the other side in the first axial direction, the first main body portion connects one end of the turning portion and the first terminal portion, and the second main body portion is separated from the first main body portion in the second axial direction and connects the other end of the turning portion and the second terminal portion; a magnetic sensor disposed on or near the conductor; and a package that seals the turning portion, the first main body portion, the second main body portion, and the magnetic sensor of the conductor and exposes the first terminal portion and the second terminal portion, and at least one of the cross-sectional area of a cross-section obtained by cutting the first terminal portion with the outer surface of the package and the cross-sectional area of a cross-section obtained by cutting the second terminal portion with the outer surface of the package is smaller than the cross-sectional area of the turning portion, and the connecting portions between the first main body portion and the turning portion and between the second main body portion and the turning portion have a rectangular shape in a top view, and the magnetic sensor is disposed on at least one of the connecting portions between the first main body portion and the turning portion and between the second main body portion and the turning portion.

[0010] In addition, the above summary of the invention does not list all the features of the present invention. In addition, sub-combinations of these feature groups can also form inventions. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The internal structure of the current sensor according to this embodiment is shown in a top view.

[0012] Figure 2A Shows a schematic structure of the sensor unit.

[0013] Figure 2B Shows the definition of rectangularity.

[0014] Figure 2C The structure of a current sensor including two magnetic sensors is shown in a top view.

[0015] Figure 2D Shows a schematic structure of the sensor unit among the two magnetic sensors.

[0016] Figure 3 Shows the definition of the cross-section and width of the conductor.

[0017] Figure 4A Shows the definition of the cross-section of the conductor.

[0018] Figure 4B Indicates the relationship between the aspect ratio of the cross-section of a rectangular-shaped conductor and the rate of change in resistance caused by the skin effect.

[0019] Figure 4C Indicates the relationship between the resistance of the conductor and the frequency.

[0020] Figure 4D A current sensor with a small aspect ratio of the cross-section of the turning portion is shown in a top view.

[0021] Figure 4E A current sensor with a large aspect ratio of the cross-section of the turning portion is shown in a top view.

[0022] Figure 5A The structure of a mounting substrate on which a current sensor is arranged is shown in a top view.

[0023] Figure 5B The structure of the current sensor and the occupied area is shown in a top view.

[0024] Figure 6A The arrangement of the conductor, the insulating layer, and the magnetic sensor is shown in a top view.

[0025] Figure 6B Shown in a side view Figure 6A The arrangement of the conductor, the insulating layer, and the magnetic sensor at the cross-section A-A' of

[0026] Figure 6C Shown in a side view Figure 6A The arrangement of the conductor, the insulating layer, and the magnetic sensor at the cross-section A-A' of

[0027] Figure 7A The structure of the current sensor of the first modification example is shown in a top view.

[0028] Figure 7B The structure of the current sensor of the second modification example is shown in a top view.

[0029] Figure 7C The structure of the current sensor of the third modification example is shown in a top view.

[0030] Figure 7D The structure of the current sensor of the fourth modification example is shown in a top view.

[0031] Figure 7E The structure of the current sensor of the fifth modification example is shown in a top view.

[0032] Figure 7F The structure of the current sensor of the sixth modification example is shown in a top view.

[0033] Reference Signs Explanation

[0034] 1, 1', 1A, 1B, 1C, 1D, 1E, 1F, 1G... Current sensors; 2... Primary circuit; 3... Secondary circuit; 10... Package; 20, 20a, 20b... Sensor parts; 21, 22, 23, 24, 21a, 21b, 22a, 22b... Magnetoelectric conversion elements; 25, 26... Terminals; 30, 30a, 30b... Magnetic sensors; 31, 31A, 31B... Substrates; 40... Conductor; 41a, 41b... Terminal parts; 41a1, 41a2, 41a3, 41a4, 41b1, 41b2, 41b3, 41b4... Terminals; 42a, 42b... Main bodies; 421a, 421b... First parts of the main bodies; 422a, 422b... Second parts of the main bodies; 43... Bending part; 50, 51, 52... Signal terminals; 70, 71, 72... Occupied areas, 80... Insulating layer, 100... Mounting substrate, L41a, L41a1, L41a2, L41a3, L41a4, L41b, L41b1, L41b2, L41b3, L41b4, L42a, L42b, L43... Widths, L50, L50', L51, L51'... Distances, S41a, S41a1, S41a2, S41a3, S41a4, S41b, S41b1, S41b2, S41b3, S41b4, S42a, S42b, S43... Cross-sections Detailed implementation manners

[0035] Hereinafter, the present invention will be described by way of embodiments of the invention. However, the following embodiments do not limit the invention recited in the claims. In addition, the combinations of features described in the embodiments are not necessarily all essential for the solution means of the invention.

[0036] In Figure 1 , the internal structure of the current sensor 1 of the present embodiment is shown through the package 10 in a top view. Here, the up-down direction of the drawing is set as the longitudinal direction, and the left-right direction is set as the lateral direction. The current sensor 1 is a sensor that measures the amount of current to be measured by using the magnetic sensor 30 to detect the magnetic field generated around the conductor 40 due to the current to be measured flowing through it, and includes a package 10, a magnetic sensor 30, a conductor 40, and a plurality of signal terminals 50.

[0037] The encapsulation body 10 is a component that protects the various parts of the structure of the current sensor 1, seals the turning part 43 of the conductor 40, the first main body part 42a, the second main body part 42b, the magnetic sensor 30, and the base end sides of the plurality of signal terminals 50, exposes the first terminal part 41a and the second terminal part 41b from the side on one longitudinal side (the lower side of the drawing), and exposes the ends of the plurality of signal terminals 50 from the side on the other longitudinal side (the upper side of the drawing). The encapsulation body 10 is molded, for example, by using a sealing resin with excellent insulation properties such as epoxy resin, and is formed into a flat cuboid shape.

[0038] The magnetic sensor 30 is a sensor that detects the magnetic field generated by the measured current flowing through the conductor 40, and includes a substrate 31 and two sensor parts 20. The magnetic sensor 30 is arranged on the conductor 40. In addition, although the magnetic sensor 30 includes two sensor parts 20, it may instead include only one of them.

[0039] The substrate 31 is a plate-like component that supports the two sensor parts 20, and a plurality of wirings (not shown) are laid on its upper surface. The substrate 31 is formed, for example, using any one of silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), aluminum nitride (AlN), sapphire (Si2O3), silicon carbide (SiC), and diamond.

[0040] Figure 2A Shows a schematic structure of the sensor part 20. The sensor part 20 is a circuit that changes the output voltage according to the magnetic flux density, and includes a plurality of (four in this example) magnetoelectric conversion elements 21, 22, 23, 24 assembled in the shape of a Wheatstone bridge (full bridge) circuit. In addition, two magnetoelectric conversion elements 21 and 23 or 22 and 24 can be used and assembled in the shape of a half bridge circuit.

[0041] The plurality of magnetoelectric conversion elements 21, 22, 23, 24 are elements whose electrical characteristics (i.e., magnetoresistance) change according to the intensity of the applied magnetic field. The magnetoelectric conversion elements 21, 22, 23, 24 are arranged such that their respective magnetosensitive directions face the horizontal direction to detect the horizontal magnetic field generated on the conductor 40 due to the measured current flowing in the arrow direction in the conductor 40. Among them, the magnetosensitive directions of the magnetoelectric conversion elements 21, 24 are the same direction, and the magnetosensitive directions of the magnetoelectric conversion elements 22, 23 are the same direction and opposite to the magnetosensitive directions of the magnetoelectric conversion elements 21, 24. As the plurality of magnetoelectric conversion elements 21, 22, 23, 24, any one of a tunnel magnetoresistance element (TMR), a giant magnetoresistance element (GMR), and an anisotropic magnetoresistance element (AMR) can be adopted. These elements can use, for example, an alloy containing at least one of Co, Fe, B, Ni, Si, and more specifically, cobalt iron (CoFe), cobalt iron boron (CoFeB), and nickel iron (NiFe). By using these elements, the current flowing through the conductor 40 can be measured precisely.

[0042] 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. Using the magnetoresistances R1, R2, R3, and R4 of magnetoelectric conversion elements 21, 22, 23, and 24 respectively, V ∝ R1 × R3 - R2 × R4 holds. Thus, the magnetic sensor 30 can measure the intensity of the magnetic field generated by the measured current flowing through the conductor 40 and can measure the amount of the measured current.

[0043] The two sensor units 20 of the magnetic sensor 30 are respectively arranged at the connection part between the first main body part 42a and the turning part 43 (the first part 421a of the first main body part 42a described later) and the connection part between the second main body part 42b and the turning part 43 (the first part 421b of the second main body part 42b described later). These connection parts have a rectangular shape in a top view as described later. Thus, by arranging the sensor units 20 on them, the magnetic field generated by energizing the conductor 40 can be concentrated on the sensor units 20, and the amount of current can be detected with high sensitivity. In addition, the connection part may be in a rectangular shape or a substantially rectangular shape in a top view.

[0044] Figure 2B The definition of the rectangularity indicating the degree of the rectangular shape of the connection part (the first part 421a of the first main body part 42a or the first part 421b of the second main body part 42b) is shown. Assume that the contour line of the connection part is represented by a solid line. The rectangularity Sin / Sout is defined using the area Sin of the rectangular region with the maximum area arranged inside the contour line of the connection part and the area Sout of the rectangular region with the minimum area arranged outside the contour line of the connection part for the two parallel sides extending horizontally and the two parallel sides extending vertically that form the rectangle. A true rectangular shape has a rectangularity of 1, and a substantially rectangular shape has a rectangularity of 0.8 or more and less than 1. The connection part is not limited to a rectangular shape in a top view and may be set to a substantially rectangular shape. Thus, the forming of the lead frame when manufacturing the conductor 40 becomes easy, and the conductor 40 can be easily adhered to the package body 10, and peeling between them can be prevented.

[0045] In addition, the sensor unit 20 may be composed of a Hall element or may be arranged inside the turning part 43 or near the conductor 40 to detect the vertical magnetic field generated due to the current flowing through the conductor 40.

[0046] Figure 2CThe structure of the current sensor 1' including two magnetic sensors 20a and 20b is shown in the top view. In the current sensor 1', alternatively, the magnetic sensor 30 may be composed of a first magnetic sensor 30a including the sensor unit 20a and a second magnetic sensor 30b including the sensor unit 20b. The sensor unit 20a of the first magnetic sensor 30a is disposed on the connecting portion (the first portion 421a of the first main body portion 42a described later) between the first main body portion 42a and the turning portion 43, and the sensor unit 20b of the second magnetic sensor 30b is disposed on the connecting portion (the first portion 421b of the second main body portion 42b described later) between the second main body portion 42b and the turning portion 43. The first magnetic sensor 30a and the second magnetic sensor 30b each include any one of a tunnel magnetoresistive element (TMR), a giant magnetoresistive element (GMR), and an anisotropic magnetoresistive element (AMR). The first magnetic sensor 30a and the second magnetic sensor 30b have opposite magnetic sensitivity directions and are wire-connected to each other. Here, magnetoresistive elements 21a and 22b, 22a and 21b having opposite magnetic sensitivity directions included in the sensor units 20a and 20b of the first magnetic sensor 30a and the second magnetic sensor 30b may also be used to form a Wheatstone bridge or a half-bridge circuit (refer to Figure 2D ). By using the magnetoresistive elements 21a and 22b, 22a and 21b having opposite magnetic sensitivity directions included in the first magnetic sensor 30a and the second magnetic sensor 30b to form a Wheatstone bridge or a half-bridge circuit, an increase in manufacturing cost can be suppressed as compared with using a tunnel magnetoresistive element (TMR) or a giant magnetoresistive element (GMR) having different sensitivity directions in one magnetic sensor 30.

[0047] The conductor (also referred to as a bus bar) 40 is a conductive member that forms a current path for the current to be measured and has a first terminal portion 41a, a second terminal portion 41b, a first main body portion 42a, a second main body portion 42b, and a turning portion 43.

[0048] The first terminal portion 41a is a terminal for inputting the current to be measured (also simply referred to as current). The first terminal portion 41a includes a plurality (four in this example) of terminals 41a1, 41a2, 41a3, 41a4 disposed on one side in the longitudinal direction (the lower side in the drawing) and protruding from the lower side surface of the package 10 in the drawing.

[0049] The second terminal portion 41b is a terminal portion for outputting current. The second terminal portion 41b includes a plurality (four in this example) of terminals 41b1, 41b2, 41b3, 41b4 disposed separated from the first terminal portion 41a in the right direction in the drawing and protruding from the lower side surface of the package 10 in the drawing. Alternatively, the second terminal portion 41b may be used as a terminal portion for inputting current, and the first terminal portion 41a may be used as a terminal portion for outputting current.

[0050] The first main body portion 42a is a portion connecting one end of the turning portion 43 and the first terminal portion 41a. The first main body portion 42a has a shape in which the cross-sectional area increases as it approaches the connection portion between the first main body portion 42a and the first terminal portion 41a from the connection portion between the first main body portion 42a and the turning portion 43, and has a first portion (also referred to as an arm portion, which is also the connection portion between the first main body portion 42a and the turning portion 43) 421a and a second portion 422a. The first portion 421a is a portion connected to the turning portion 43 and having a rectangular shape in a top view. The second portion 422a is a portion connected to the terminal portion 41a and widening as it approaches the first terminal portion 41a from the first portion 421a.

[0051] The second main body portion 42b is a portion connecting the other end of the turning portion 43 and the second terminal portion 41b, and is disposed separately from the first main body portion 42a toward the right side of the drawing. The second main body portion 42b has a shape in which the cross-sectional area increases as it approaches the connection portion between the second main body portion 42b and the second terminal portion 41b from the connection portion between the second main body portion 42b and the turning portion 43, and has a first portion (which is also the connection portion between the second main body portion 42b and the turning portion 43) 421b and a second portion 422b. The first portion 421b is a portion connected to the turning portion 43 and having a rectangular shape in a top view. The second portion 422b is a portion connected to the terminal portion 41b and widening as it approaches the second terminal portion 41b from the first portion 421b.

[0052] The turning portion 43 is a portion connected to the two main body portions 42a and 42b at both ends thereof, and is disposed on the other side in the longitudinal direction (the upper side of the drawing), and has a shape extending from one side in the longitudinal direction (the lower side of the drawing) to the other side (the upper side of the drawing) and bending laterally and returning to one side, and as an example, has a substantially arc shape. It should be noted that the turning portion 43 may also be bent into a "コ (Japanese kana)" shape, an inverted V shape, or a "П (Cyrillic letter)" shape. The turning portion 43 inputs the current to be measured from the first main body portion 42a and outputs the current to be measured to the second main body portion 42b.

[0053] By including the first terminal portion 41a, the second terminal portion 41b, the first main body portion 42a, the second main body portion 42b, and the turning portion 43 formed as described above, the conductor 40 has a substantially U-shaped configuration that returns from the first terminal portion 41a on the left side of the lower side of the drawing of the package body 10 through the inside of the package body 10 to the lower side of the drawing and reaches the second terminal portion 41b on the right side of the lower side of the drawing. The conductor 40 can be formed using a conductive metal such as copper, for example.

[0054] The multiple signal terminals 50 are components for sending the output signals of the magnetic sensor 30 to the secondary circuit 3 (described in detail later). They are separated from the conductor 40 toward the upper side in the drawing and are sealed in the package 10 with their ends exposed from the side surface on the upper side in the drawing. The multiple signal terminals 50 can be formed using a conductive metal such as copper, for example. The multiple signal terminals 50 are wire-bonded to the magnetic sensor 30. In addition, the end portions exposed from the package 10 are connected to the secondary circuit 3 on the mounting substrate 100 when the current sensor 30 is mounted on the mounting substrate 100.

[0055] Since the conductor 40 has a minute resistance, it generates heat when current flows through it. Here, when an instantaneous overcurrent generated during a fault flows through the conductor 40, the distribution ΔT of the temperature change in the conductor 40 is slow enough via the heat dissipation of the package to be negligible. Thus, for the position r on the conductor 40, it is expressed as follows.

[0056] [Equation 1]

[0057] ΔT(r) = q(r) / c(r) × Δt (1)

[0058] Here, q is the heat generation amount per unit volume, c is the heat capacity per unit volume, and Δt is the heating time. In the case of the conductor 40 with uniform material and thickness, c is constant regardless of the position r, and the temperature change ΔT is determined by the Joule heat, that is, the current density. That is, the position r to which the load caused by heat generation is applied is determined by the current density at that position r. Therefore, if the resistivity in the conductor 40 is the same, the current density is determined by the cross-sectional area of the conductor 40 along the current path. Thus, the load caused by heat generation is concentrated on the position r on the current path with a small cross-sectional area.

[0059] Figure 3 The definitions of the cross-sections S41a, S41b, S42a, S42b, and S43 of the conductor 40 are shown. The cross-section S41a is the cross-section obtained by cutting the first terminal portion 41a with the outer surface of the package 10 and includes the cross-sections S41a1, S41a2, S41a3, and S41a4 of the respective terminals 41a1, 41a2, 41a3, and 41a4. The cross-section S41b is the cross-section obtained by cutting the second terminal portion 41b with the outer surface of the package 10 and includes the cross-sections S41b1, S41b2, S41b3, and S41b4 of the respective terminals 41b1, 41b2, 41b3, and 41b4. The cross-section S42a is the cross-section of the connecting portion between the first main body portion 42a and the turning portion 43. The cross-section S42b is the cross-section of the connecting portion between the second main body portion 42b and the turning portion 43. The cross-section S43 is the cross-section on the central axis of the conductor 40 parallel to the longitudinal direction in the turning portion 43. The cross-sectional area of the turning portion 43 is given by the area of the cross-section S43.

[0060] Here, at least one of the cross-sectional areas of the cross-section S41a and the cross-section S41b is set to be smaller than the cross-sectional area of the cross-section S43 of the turning portion 43. Thus, even when an overcurrent flows when detecting the current amount by measuring the magnetic field generated by energizing the conductor 40 using the magnetic sensor 30 disposed above the conductor 40, the current concentrates on the connection portion between the first terminal portion 41a and the first main body portion 42a near the outer surface of the package body 10, or the connection portion between the second terminal portion 41b and the second main body portion 42b, resulting in a failure. Therefore, it is easy to confirm the failure of the current sensor 1 from outside the package body 10.

[0061] In addition, at least one of the sum of the cross-sectional areas of the cross-sections S41a1 to S41a4 and the sum of the cross-sectional areas of the cross-sections S41b1 to S41b4 is set to be smaller than the cross-sectional area of the turning portion 43. Thus, the cross-sectional areas of the first main body portion 42a and the second main body portion 42b are increased to reduce the resistance, and the cross-sectional areas of the first terminal portion 41a and the second terminal portion 41b are reduced by including a plurality of terminals 41a1 to 41a4, 41b1 to 41b4 to increase the resistance. Therefore, even when an overcurrent flows, the current concentrates on any one of the plurality of terminals 41a1 to 41a4, 41b1 to 41b4 at the connection portion between the first terminal portion 41a and the first main body portion 42a and the connection portion between the second terminal portion 41b and the second main body portion 42b near the outer surface of the package body 10, resulting in a failure. Therefore, the failure of the current sensor can be confirmed from outside the package body 10.

[0062] In addition, at least one of the cross-sectional area of the cross-section S41a and the cross-sectional area of the cross-section S41b is determined to be smaller than the cross-sectional area of the cross-section S42a of the connection portion between the turning portion 43 and the first main body portion 42a and the cross-sectional area of the cross-section S42b of the connection portion between the turning portion 43 and the second main body portion 42b. Thus, compared with the connection portion between the turning portion 43 and the first main body portion 42a and the connection portion between the turning portion 43 and the second main body portion 42b, the current concentrates on at least one of the cross-section S41a obtained by cutting the first terminal portion 41a using the outer surface of the package body 10 and the cross-section S41b obtained by cutting the second terminal portion 41b using the outer surface of the package body 10, and the temperature increases, resulting in a failure. Therefore, it is easy to confirm the failure of the current sensor from outside the package body 10.

[0063] Here, when an overcurrent that causes a failure due to an increase in temperature by concentrating on at least one of the cross-sections S41b flows through the conductor 40 for an instant, the current concentrates near the turning portion 43. That is, when an overcurrent flows through the conductor 40 for an instant, after the first terminal portion 41a outside the package body 10, the current easily concentrates near the turning portion 43 and easily becomes high temperature.

[0064] In the present invention, the sensor unit 20 is not disposed on the turning portion 43, but on the connecting portions between the first main body portion 42a and the turning portion 43 (the first portion 421a of the first main body portion 42a described later) and between the second main body portion 42b and the turning portion 43 (the first portion 421b of the second main body portion 42b described later). Thereby, thermal damage to the sensor during a failure can be prevented, and the current amount can be detected with high sensitivity.

[0065] Figure 3 It also shows the definitions of the widths L41a, L41b, L42a, L42b, and L43 of the conductor 40. The width L41a is the width of the cross-section S41a obtained by cutting the first terminal portion 41a with the outer surface of the package 10, and is the sum of the widths L41a1, L41a2, L41a3, and L41a4 of the respective terminals 41a1, 41a2, 41a3, and 41a4. The width L41b is the width of the cross-section S41b obtained by cutting the second terminal portion 41b with the outer surface of the package 10, and is the sum of the widths L41b1, L41b2, L41b3, and L41b4 of the respective terminals 41b1, 41b2, 41b3, and 41b4. The width L42a is the width of the connecting portion between the first main body portion 42a and the turning portion 43. The width L42b is the width of the connecting portion between the second main body portion 42b and the turning portion 43. The width L43 is the width on the central axis of the conductor 40 parallel to the longitudinal direction of the turning portion 43.

[0066] Here, the thickness of the conductor 40 is substantially constant, and at least one of the width L41a of the cross-section S41a obtained by cutting the first terminal portion 41a with the outer surface of the package 10 and the width L41b of the cross-section S41b obtained by cutting the second terminal portion 41b with the outer surface of the package 10 is set to be smaller than the width L43 of the turning portion 43. Thereby, when the plate thickness is substantially constant, at least one of the cross-sectional area of the cross-section S41a obtained by cutting the first terminal portion 41a with the outer surface of the package 10 and the cross-sectional area of the cross-section S41b obtained by cutting the second terminal portion 41b with the outer surface of the package 10 is smaller than the cross-sectional area of the cross-section S43 of the turning portion 43. Therefore, it can be configured to be able to confirm a failure at the first terminal portion 41a or the second terminal portion 41b instead of the turning portion 43.

[0067] In addition, at least one of the width L41a of the cross-section S41a obtained by cutting the first terminal portion 41a using the outer surface of the package body 10 and the width L41b of the cross-section S41b obtained by cutting the second terminal portion 41b using the outer surface of the package body 10 is further set to be smaller than the width L42a of the connecting portion between the first main body portion 42a and the turning portion 43 and the width L42b of the connecting portion between the second main body portion 42b and the turning portion 43. Thus, when the plate thickness is constant, at least one of the cross-sectional area of the cross-section S41a obtained by cutting the first terminal portion 41a using the outer surface of the package body 10 and the cross-sectional area of the cross-section S41b obtained by cutting the second terminal portion 41b using the outer surface of the package body 10 is smaller than the cross-sectional area of the cross-section S42a of the connecting portion between the turning portion 43 and the first main body portion 42a and the cross-sectional area of the cross-section S42b of the connecting portion between the turning portion 43 and the second main body portion 42b, and it can be configured such that a failure can be confirmed not at the turning portion 43, the connecting portion between the first main body portion 42a and the turning portion 43, or the connecting portion between the second main body portion 42b and the turning portion 43, but at the first terminal portion 41a or the second terminal portion 41b.

[0068] The measured current flowing through the conductor 40 is not limited to a direct current, and may also be an alternating current. When the measured current is an alternating current, the conductor 40 exhibits the skin effect. The skin effect refers to the phenomenon that when an alternating current flows through the conductor 40, the higher the frequency of the current, the more concentrated the current is near the surface of the conductor 40, and the more difficult it is for the current to flow away from the surface of the conductor 40, resulting in a temperature rise inside the conductor 40. Therefore, by increasing the surface ratio with respect to the cross-sectional area of each part of the conductor 40, even when the skin effect is generated due to high-frequency current, an increase in the resistance of each part can be prevented.

[0069] Figure 4A The definitions of the cross-sections S43, S41a, S41b, S42a, and S42b of the conductor 40 are shown.

[0070] Figure 4BThe relationship between the aspect ratio and the rate of change of resistance caused by the skin effect with respect to the case where the aspect ratio is 1, when the cross-section of the conductor 40 is rectangular and the long side / short side is defined as the aspect ratio. When the conductor is made of copper, the skin depth δ (unit: mm) is δ = 75 / √f. Here, f is the frequency of the current (unit: Hz). Assuming a cross-section with a short side t and a long side W, the resistance R(0) for direct current and the resistance R(f) for alternating current with frequency f are R(0) ∝ 1 / (t×W) and R(f) ∝ 1 / (2(t + W)δ). Therefore, the rate of increase in resistance due to the skin effect for a rectangular cross-section with a short side t and a long side W (aspect ratio A = W / t) is ΔR(A) = R(f) / R(0) = (t×W) / (2(t + W)δ). When the cross-sectional area t×W = S is constant, we can write t = √(S / A) and W = √(S×A). Thus, the rate of change of the increase in resistance due to the skin effect with respect to the case where the aspect ratio A = 1 is ΔR(A) / ΔR(1) = (2(√(S / 1)+√(S×1))δ) / (2(√(S / A)+√(S×A))δ) = 2 / (1 / √A + √A). Therefore, by increasing the aspect ratio from 1 for the same cross-sectional area, the increase in resistance due to the skin effect can be suppressed.

[0071] The cross-section S43 is the cross-section of the conductor 40 at the turning portion 43. The length of the short side of the cross-section S43 is equal to the thickness of the conductor 40, and the length of the long side is equal to the width L43 of the turning portion 43. When the thickness of the conductor 40 is approximately constant, the length of the short side of the cross-section S43 is equal to the short sides of the cross-sections S42a and S42b and the long sides of the cross-sections S41a1 to S41a4 and S41b1 to S41b4. When the long side and the short side of a rectangular cross-section are defined as the aspect ratio with the long side / short side, the aspect ratio of the cross-section S43 is 1.4 to 2.7. By increasing the surface area with respect to the area of the turning portion 43, even for alternating current that generates the skin effect, the resistance at the turning portion 43 will not increase, and temperature changes can be suppressed through the first terminal portion 41a or the second terminal portion 41b. In addition, by setting the aspect ratio of the cross-section S43 to 1.4, the rate of increase in resistance due to the skin effect can be reduced by 1%. More preferably, by setting the aspect ratio to 2.0, the rate of increase in resistance due to the skin effect can be reduced by 6%. More preferably, by setting the aspect ratio to 2.5, the rate of increase in resistance due to the skin effect can be reduced by 10%. However, if the aspect ratio is greater than 2.7, it will lead to an increase in the size of the package and difficulty in processing, which is not preferred.

[0072] As described above, the cross-section S41a is the cross-section of the conductor 40 obtained by cutting the first terminal portion 41a using the outer surface of the package 10 (see Figure 3)。The lengths of the short sides of the cross-sections S41a1, S41a2, S41a3, and S41a4 of the respective multiple terminals 41a1, 41a2, 41a3, and 41a4 are equal to the top-view widths L41a1 to L41a4 of the respective multiple terminals 41a1 to 41a4, and the lengths of the long sides are equal to the thickness of the conductor 40. When the thickness of the conductor 40 is substantially constant, the lengths of the long sides of the cross-sections S41a1 to S41a4 are equal to the lengths of the short sides of the cross-sections S43, S42a, and S42b and the lengths of the long sides of the cross-sections S41b1 to S41b4.

[0073] As described above, the cross-section S41b is a cross-section of the conductor 40 obtained by cutting the second terminal portion 41b using the outer surface of the package 10. The lengths of the short sides of the cross-sections S41b1, S41b2, S41b3, and S41b4 of the respective multiple terminals 41b1, 41b2, 41b3, and 41b4 are equal to the top-view widths L41b1 to L41b4 of the respective multiple terminals 41b1 to 41b4, and the lengths of the long sides are equal to the thickness of the conductor 40. When the thickness of the conductor 40 is substantially constant, the lengths of the long sides of the cross-sections S41b1 to S41b4 are equal to the lengths of the short sides of the cross-sections S43, S42a, and S42b and the lengths of the long sides of the cross-sections S41a1 to S41a4.

[0074] By making the aspect ratios in both the cross-section S41a and the cross-section S41b be 1.4 to 2.7, the surface area with respect to the areas of the first terminal portion 41a and the second terminal portion 41b increases, and for alternating current that generates the skin effect, the resistance at the first terminal portion 41a and the second terminal portion 41b does not increase, and it is possible to prevent the situation where the first terminal portion 41a or the second terminal portion 41b is prone to excessive failure. In addition, by making the aspect ratios of the cross-sections S41a1 to S41a4 and S41b1 to S41b4 be 1.4, the resistance increase rate caused by the skin effect can be reduced by 1%. More preferably, by setting the aspect ratio to 2.0, the resistance increase rate caused by the skin effect can be reduced by 6%. More preferably, by setting the aspect ratio to 2.5, the resistance increase rate caused by the skin effect can be reduced by 10%. However, if the aspect ratio is greater than 2.7, it leads to an increase in the size of the package and an increase in the difficulty of processing, which is not preferred.

[0075] As described above, the cross-section S42a is a cross-section of the conductor 40 at the connection portion between the first main body portion 42a and the turning portion 43. The length of the short side of the cross-section S42a is equal to the thickness of the conductor 40, and the length of the long side is equal to the width L42a of the connection portion between the turning portion 43 and the first main body portion 42a. When the thickness of the conductor 40 is substantially constant, the length of the short side of the cross-section S42a is equal to the lengths of the short sides of the cross-sections S43 and S42b and the lengths of the long sides of the cross-sections S41a1 to S41a4 and S41b1 to S41b4.

[0076] As described above, the cross-section S42b is the cross-section of the conductor 40 at the connecting portion between the second main body portion 42b and the turning portion 43 (see Figure 3 ). The length of the short side of the cross-section S42b is equal to the thickness of the conductor 40, and the length of the long side is equal to the width L42b of the connecting portion between the turning portion 43 and the second main body portion 42b. When the thickness of the conductor 40 is substantially constant, the length of the short side of the cross-section S42b is equal to the length of the short sides of the cross-sections S43, S42a and the lengths of the long sides of the cross-sections S41a1 to S41a4, S41b1 to S41b4.

[0077] By making the aspect ratios in the cross-sections S42a and S42b both 1.4 to 2.7, the surface areas of the first main body portion 42a and the second main body portion 42b with respect to the area of the connecting portion with the turning portion 43 increase. Even for the alternating current that generates the skin effect in the cross-section S42b, the resistance at the turning portion 43, the first main body portion 42a, or the second main body portion 42b will not increase, and the temperature change can be suppressed compared with the first terminal portion 41a or the second terminal portion 41b. However, when the aspect ratios of the cross-sections S42a and S42b are less than 1.4, the increase in resistance caused by the skin effect cannot be sufficiently prevented, and when it exceeds 2.7, it is impossible to miniaturize the current sensor 1 in order to ensure the withstand voltage between the first part 421 of the main body and the signal terminal 50.

[0078] Figure 4C It shows the relationship between the resistance of the conductor 40 and the frequency. The solid line is the relationship between the resistance and the frequency when the surface ratio with respect to the cross-sectional area of each part of the conductor 40 is high. As described above, even when the frequency becomes high and the skin effect occurs, the resistance will not increase significantly. The dashed line is the relationship between the resistance and the frequency when the surface ratio with respect to the cross-sectional area of each part of the conductor 40 is low. As described above, when the frequency becomes high, the resistance increases due to the occurrence of the skin effect. The thick line is the relationship between the resistance of the turning portion 43 of the conductor 40 and the frequency. The thin line is the relationship between the resistance of the turning portion 43 of the conductor 40 and the frequency, that is, the relationship between the resistance of the terminal portions 41a and 41b and the frequency. By increasing the surface ratio with respect to the cross-sectional area of each part of the conductor 40, the increase in resistance with respect to the frequency can be suppressed. The resistance of the turning portion 43 and the terminal portions 41a and 41b is not easily increased by the frequency. Thus, even when a high-frequency alternating current flows as an overcurrent, failures of each part of the conductor 40 can be suppressed.

[0079] In Figure 4D and Figure 4EAmong them, a current sensor with different aspect ratios of the cross-section S43 of the turning portion 43 is shown in the top view. If the aspect ratio of the turning portion 43 is increased, the width of the turning portion 43 becomes larger. With the size of the package 10 remaining unchanged, the separation distance between the turning portion 43 and the signal terminal 50 becomes smaller. Therefore, the dielectric withstand voltage between the turning portion 43 and the signal terminal 50 cannot be ensured. Thus, if the aspect ratio of the turning portion 43 is increased, in order to maintain the separation distance between the turning portion 43 and the signal terminal 50 and ensure the dielectric withstand voltage, the package 10 becomes larger and the current sensor 1 becomes larger.

[0080] Figure 5A The structure of the mounting substrate 100 on which the current sensor 1 is mounted is shown in the top view. The mounting substrate 100 is a substrate having the current sensor 1, the primary circuit 2, and the secondary circuit 3. In the mounting substrate 100, the measured current 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. In addition, the current sensor 1 is configured as described above.

[0081] The primary circuit 2 is a circuit that inputs the measured current 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.

[0082] The secondary circuit 3 is a circuit that operates according to the output signal of the current sensor 1 and includes a plurality of occupied regions 70 respectively connected to a plurality of circuits (not shown). The plurality of occupied regions 70 are respectively connected to a plurality of signal terminals 50 (refer to Figure 5B ), 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 occupied regions 70 include an occupied region 71 and an occupied region 72.

[0083] The occupied region 71 is at least one of the plurality of occupied regions 70 and is connected to the signal terminal 51 among the plurality of signal terminals 50 (refer to Figure 5B ).

[0084] The occupied region 72 is the remaining occupied regions among the plurality of occupied regions 70 other than the occupied region 71 and is connected to the signal terminal 52 among the plurality of signal terminals 50 (refer to Figure 5B ).

[0085] In Figure 5B the configuration of the current sensor 1 and the plurality of occupied regions 70 and the definitions of the distances L51, L51’, L50, and L50’ are shown in the top view. As described above, the signal terminal 51 and the signal terminal 52 among the plurality of signal terminals 50 (refer to Figure 5B) are respectively connected to the occupied area 71 and the occupied area 72 among the plurality of occupied areas 70. The distance L51 is the separation distance between the signal terminal 51 and the turning portion 43 of the conductor 40. The distance L51' is the separation distance between the signal terminal 51 and the main body portion 42 of the conductor 40. The distance L50 is the separation distance between the other signal terminal 52 and the turning portion 43 of the conductor 40. The distance L50 can also be set as the minimum value of the separation distances between each of the other signal terminals 52 and the turning portion 43. The distance L50' is the separation distance between the other signal terminal 52 and the main body portions 42a, 42b of the conductor 40. The distance L50' can also be set as the minimum value of the separation distances between each of the other signal terminals 52 and the main body portions 42a, 42b.

[0086] In the above configuration, the distance L51 is shorter than the distance L50. In other words, the signal terminal 51 is closer to the turning portion 43 than the other signal terminals 52. Thus, heat generated at the turning portion 43 can be dissipated to the outside of the package 10 via the signal terminal 51 that is closer to the turning portion 43 among the plurality of signal terminals 50. To ensure insulation, the distance L51 between the turning portion 43 and the signal terminal 51 is preferably 0.4 mm or more. In addition, the signal terminal 51 can be a GND terminal. Since the signal terminal 51 that is closer to the turning portion 43 is a GND terminal, in the case of arc discharge occurring at the turning portion 43, induced discharge from the adjacent signal terminal 51 to the GND can suppress damage to the multiple circuits on the secondary circuit 3 connected to the other signal terminals 52.

[0087] Moreover, the distance L51 is shorter than the distance L50, and the distance L51' is shorter than the distance L50'. In other words, the signal terminal 51 is closer to either the turning portion 43 or either the first main body portion 42a or the second main body portion 42b than the other signal terminals 52 included in the plurality of signal terminals 50. Thus, since the signal terminal 51 that is closest to the turning portion 43, the first main body portion 42a, and the second main body portion 42b is a GND terminal, in the case of arc discharge occurring at the turning portion 43 or the main body portion 42, guiding the discharge from the adjacent signal terminal 51 to the GND can suppress damage to the multiple circuits on the secondary circuit 3 connected to the other signal terminals 52.

[0088] When the current sensor 1 is mounted on the mounting substrate 100, the signal terminal 51 is connected to the occupied area 71 on the mounting substrate 100 that has a larger area than the occupied area 72 to which the other signal terminals 52 are connected. Thus, since the signal terminal 51 to which heat is transferred from the turning portion 43 is connected to the occupied area 71 on the mounting substrate that has a larger area than the occupied area 72 to which the other signal terminals 52 are connected, the signal terminal 51 has a larger heat dissipation area and can dissipate heat efficiently, and the heat dissipation performance of the turning portion 43 can be improved to prevent failures caused by heat accumulation. The occupied area 71 preferably has an area that is 1.5 to 40 times that of the other occupied area 72.

[0089] Figure 6A The configuration of the conductor 40, the insulating layer 80, and the magnetic sensor 30 is shown in the top view. The insulating layer 80 is a member 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 80 can be formed, for example, of a polyimide layer, glass, paper, Teflon (registered trademark), or silicon.

[0090] The magnetic sensor 30 is disposed on the conductor 40 with the insulating layer 80 therebetween, and the contour line of the insulating layer 80 is located between the contour line of the magnetic sensor 30 and the outer contour line of the conductor 40. To ensure insulation, the contour line of the insulating layer 80 preferably has a distance of 0.4 mm or more from the contour line of the magnetic sensor 30 toward the outside. Thus, the insulating layer 80 insulates the magnetic sensor 30 from the conductor 40 without covering the entire upper surface of the conductor 40, and the insulating layer 80 does not impede the heat dissipation of the conductor 40 and does not reduce the heat dissipation performance of the conductor 40.

[0091] Figure 6B and Figure 6C is shown in the side view Figure 6A of the configuration of the conductor 40, the insulating layer 80, and the magnetic sensor 30 at the cross-section A-A'. As Figure 6B shown, when the contour line of the insulating layer 80 is located between the contour line of the magnetic sensor 30 and the outer contour line of the conductor 40, the insulating layer 80 does not cover the entire upper surface of the conductor 40, and the conductor 40 can have a heat dissipation surface. On the other hand, as Figure 6C shown, when the contour line of the insulating layer 80 is located outside the contour line of the magnetic sensor 30 and the outer contour line of the conductor 40, the insulating layer 80 covers the conductor 40, and the conductor 40 cannot ensure a sufficiently large heat dissipation surface, and the heat dissipation performance is impeded.

[0092] Figures 7A to 7F The structures of the current sensors 1A, 1B, 1C, 1D, 1E, and 1F in each modification are shown in a top view.

[0093] Figure 7A The structure of the current sensor 1A of the first modification is shown. In addition, reference numerals are omitted for the structures common to Figure 1 The current sensor 1A includes an inverted U-shaped turning portion 43 and first portions 421a and 421b of the main body; and a magnetic sensor 30A disposed on the first portions 421a and 421b of the main body. The substrate 31A extends on the turning portion 43, and the longitudinal width of the substrate 31A is longer than the length of the first portions 421a and 421b of the main body. By extending the substrate of the magnetic sensor 30A on the turning portion 43, the substrate is close to the signal terminal 50, and wire bonding of the signal terminal 50 becomes easy, improving manufacturability.

[0094] Figure 7BShows the structure of the current sensor 1B of the second modification example. In addition, the reference numerals are omitted for the structures Figure 1 that are common. The current sensor 1B includes: an inverted U-shaped turning portion 43 and first portions 421a and 421b of the main body; and a magnetic sensor 30B disposed on the first portions 421a and 421b of the main body. The substrate 31B extends on the second portions 422a and 422b of the main body, and the longitudinal width of the substrate 31B is longer than the length of the first portions 421a and 421b of the main body. The substrate 31B of the magnetic sensor 30B extends on the second portion 422 of the main body, so that the substrate is away from the turning portion 43 which is a heat generating portion. Therefore, the temperature rise of the substrate 31B of the magnetic sensor 30B can be suppressed, and the reliability of current measurement is improved.

[0095] Figure 7C Shows the structure of the current sensor 1C of the third modification example. In addition, the reference numerals are omitted for the structures Figure 1 that are common. The current sensor 1C includes: first portions 421aC and 421bC of the main body, which are as short as possible and have a length shorter than that of the substrate 30; a substantially arc-shaped turning portion 43C; and a magnetic sensor 30 that straddles the shortened first portions 421aC and 421bC of the main body. By shortening the first portions 421aC and 421bC of the main body as much as possible, the resistance of the conductor 40C can be reduced, and temperature changes can be suppressed. By connecting the turning portion 43C at the narrowest part of the flow path starting from the second portions 422aC and 422bC of the main body, the magnetic field generated by the measured current can be enhanced by increasing the current density and aligning the current longitudinally, and the same function as the first portions 421aC and 421bC of the main body can be obtained in the dashed line part in the figure.

[0096] Figure 7D Shows the structure of the current sensor 1D of the fourth modification example. In addition, the reference numerals are omitted for the structures Figure 1 that are common. The current sensor 1D includes: a "コ (Japanese kana)"-shaped turning portion 43D and first portions 421aD and 421bD of the main body; and a magnetic sensor 30 on the first portions 421aD and 421bD of the main body. By forming the turning portion 43D and the first portions 421aD and 421bD of the main body into a "コ (Japanese kana)" shape, the processing of the conductor 40D becomes easy, and the design of the signal terminal 50 also becomes easy.

[0097] Figure 7E Shows the structure of the current sensor 1E of the fifth modification example. In addition, the reference numerals are omitted for the structures Figure 1Reference numerals are omitted for the common structures. The current sensor 1E includes: an inverted V-shaped turning portion 43E and first portions 421aE and 421bE of the main body; and magnetic sensors 30 on the first portions 421aE and 421bE of the main body. By forming the turning portion 43E and the first portions 421aE and 421bE of the main body in an inverted V shape, the turning portion 43E can be designed to be small-sized.

[0098] Figure 7F Fig. shows the structure of the current sensor 1F according to the sixth modification example. In addition, for Figure 1 Reference numerals are omitted for the common structures. The current sensor 1F includes: a "П (Cyrillic letter)"-shaped turning portion 43F and a first portion 421F of the main body; and magnetic sensors 30 on the first portions 421aF and 421bF of the main body. By forming the turning portion 43F and the first portions 421aF and 421bF of the main body in a "П (Cyrillic letter)" shape, the plan view area of the turning portion 43F can be increased, and the heat dissipation performance of the turning portion 43F can be improved.

[0099] As described above, the current sensor 1 of the present embodiment includes: a conductor 40 having a first terminal portion 41a, a second terminal portion 41b, a turning portion 43, a first main body portion 42a, and a second main body portion 42b. The first terminal portion 41a is disposed on one side in a first axial direction and is used to input current. The second terminal portion 41b is separated from the first terminal portion 41a in a second axial direction intersecting the first axial direction and is used to output current. The turning portion 43 is disposed on the other side in the first axial direction. The first main body portion 42a connects one end of the turning portion and the first terminal portion 41a. The second main body portion 42b is separated from the first main body portion 42a in the second axial direction and connects the other end of the turning portion 43 and the second terminal portion 41b. A magnetic sensor 30 is disposed on or near the conductor 40. And an encapsulation body 10 seals the turning portion 43, the first main body portion 42a, the second main body portion 42b, and the magnetic sensor 30 of the conductor 40 and exposes the first terminal portion 41a and the second terminal portion 41b. The area of a cross-section S41a obtained by cutting the first terminal portion 41a with the outer surface of the encapsulation body 10 and the area of a cross-section S41b obtained by cutting the second terminal portion 41b with the outer surface of the encapsulation body 10 are at least one of which is smaller than the area of the cross-section S43 of the turning portion 43. Thus, the areas of the cross-sections S41a and S41b of the first terminal portion 41a and the second terminal portion 41b of the conductor 40 near the outer surface of the encapsulation body 10 are smaller than the area of the cross-section S43 of the turning portion 43 disposed inside the encapsulation body 10. Thus, when detecting the current amount by measuring the magnetic field generated by energizing the conductor 40 with the magnetic sensor 30 disposed on or near the conductor 40, even if an overcurrent flows, the current will concentrate on the first terminal portion 41a or the second terminal portion 41b near the outer surface of the encapsulation body 10 and a failure will occur, so that it is easy to confirm the failure of the current sensor 1 from outside the encapsulation body 10.

[0100] As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. For those skilled in the art, it is obvious that various changes or improvements can be made to the above embodiments. According to the description in the claims, the embodiments to which such changes or improvements are applied are also included in the technical scope of the present invention.

[0101] It should be noted that the execution order of each process such as the actions, sequences, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings can be implemented in any order as long as it is not specifically stated as "before", "preceding", etc., and as long as the output of the previous process is not used in the subsequent process. Regarding the action flow in the claims, the specification, and the drawings, even if it is described for convenience using "first", "next", etc., it does not mean that it must be implemented in this order.

Claims

1. A current sensor, comprising: A conductor having a first terminal portion, a second terminal portion, a turning portion, a first main body portion, and a second main body portion, wherein the first terminal portion is disposed on one side of a first axial direction and is used for inputting current, the second terminal portion is separated from the first terminal portion in a second axial direction intersecting the first axial direction and is used for outputting the current, the turning portion is disposed on the other side of the first axial direction, the first main body portion connects one end of the turning portion and the first terminal portion, and the second main body portion is separated from the first main body portion in the second axial direction and connects the other end of the turning portion and the second terminal portion; A magnetic sensor disposed on or near the conductor; And An encapsulation body that seals the turning portion, the first main body portion, the second main body portion, and the magnetic sensor of the conductor and exposes the first terminal portion and the second terminal portion, The cross-sectional area of at least one of the cross-section obtained by cutting the first terminal portion with the outer surface of the encapsulation body and the cross-section obtained by cutting the second terminal portion with the outer surface of the encapsulation body is smaller than the cross-sectional area of the turning portion, The connection portion between the first main body portion and the turning portion and the connection portion between the second main body portion and the turning portion have a substantially rectangular shape when viewed from above, The magnetic sensor is disposed on at least one of the connection portion between the first main body portion and the turning portion and the connection portion between the second main body portion and the turning portion.

2. A current sensor, comprising: A conductor having a first terminal portion, a second terminal portion, a turning portion, a first main body portion, and a second main body portion, wherein the first terminal portion is disposed on one side of a first axial direction and is used for inputting current, the second terminal portion is separated from the first terminal portion in a second axial direction intersecting the first axial direction and is used for outputting the current, the turning portion is disposed on the other side of the first axial direction, the first main body portion connects one end of the turning portion and the first terminal portion, and the second main body portion is separated from the first main body portion in the second axial direction and connects the other end of the turning portion and the second terminal portion; A magnetic sensor disposed on or near the conductor; And An encapsulation body that seals the turning portion, the first main body portion, the second main body portion, and the magnetic sensor of the conductor and exposes the first terminal portion and the second terminal portion, The cross-sectional area of at least one of the cross-section obtained by cutting the first terminal portion with the outer surface of the encapsulation body and the cross-section obtained by cutting the second terminal portion with the outer surface of the encapsulation body is smaller than the cross-sectional area of the turning portion, The connection portion between the first main body portion and the turning portion and the connection portion between the second main body portion and the turning portion have a rectangular shape when viewed from above, The magnetic sensor is disposed on at least one of the connection portion between the first main body portion and the turning portion and the connection portion between the second main body portion and the turning portion.

3. The current sensor according to claim 1 or 2, wherein, The first main body portion has a shape in which the cross-sectional area increases as it approaches the connection portion between the first main body portion and the first terminal portion from the connection portion between the first main body portion and the turning portion. The second main body portion has a shape in which the cross-sectional area increases as it approaches the connection portion between the second main body portion and the second terminal portion from the connection portion between the second main body portion and the turning portion. The first terminal portion and the second terminal portion each include a plurality of terminals. The sum of the cross-sectional areas of the cross-sections obtained by cutting the first terminal portion using the outer surface of the encapsulation body and at least one of the sum of the cross-sectional areas of the cross-sections obtained by cutting the second terminal portion using the outer surface of the encapsulation body is smaller than the cross-sectional area of the turning portion.

4. The current sensor according to claim 1 or 2, wherein The turning portion has a shape that extends from one side of the first axial direction to the other side and bends in the second axial direction and returns to the one side. The cross-sectional area of the turning portion is given by the cross-sectional area on the central axis of the conductor, and the central axis is parallel to the first axial direction.

5. The current sensor according to claim 1, wherein At least one of the cross-sectional area of the cross-section obtained by cutting the first terminal portion using the outer surface of the encapsulation body and the cross-sectional area of the cross-section obtained by cutting the second terminal portion using the outer surface of the encapsulation body is smaller than the minimum value of the cross-sectional area of the connection portion between the turning portion and the first main body portion and the minimum value of the cross-sectional area of the connection portion between the turning portion and the second main body portion.

6. The current sensor according to claim 2, wherein At least one of the cross-sectional area of the cross-section obtained by cutting the first terminal portion using the outer surface of the encapsulation body and the cross-sectional area of the cross-section obtained by cutting the second terminal portion using the outer surface of the encapsulation body is smaller than the cross-sectional area of the connection portion between the turning portion and the first main body portion and the cross-sectional area of the connection portion between the turning portion and the second main body portion.

7. The current sensor according to claim 1 or 2, wherein The current sensor further includes a plurality of signal terminals, and the plurality of signal terminals are separated from the conductor toward one side of the first axial direction and are hermetically sealed in the encapsulation body with their ends exposed. At least one of the plurality of signal terminals is closer to the turning portion than the other signal terminals.

8. The current sensor according to claim 7, wherein The at least one signal terminal is a GND terminal.

9. The current sensor according to claim 8, wherein The at least one signal terminal is closer to the turning portion, the first main body portion, and the second main body portion than the other signal terminals.

10. The current sensor according to claim 7, wherein When the current sensor is mounted on a mounting substrate, the at least one signal terminal is connected to an occupancy area on the mounting substrate that is larger than the occupancy area for connecting the other signal terminals.

11. The current sensor according to claim 1 or 2, wherein The magnetic sensor is disposed on the conductor with an insulating layer therebetween. The contour line of the insulating layer is located between the contour line of the magnetic sensor and the outer contour line of the conductor.

12. The current sensor according to claim 1 or 2, wherein, When the ratio of the long side to the short side of a rectangle is defined as the aspect ratio, The aspect ratio of the cross-section of the conductor in the turning portion is 1.4 to 2.

7.

13. The current sensor according to claim 12, wherein, The aspect ratio of the cross-section obtained by cutting the first terminal portion with the outer surface of the encapsulation body and the aspect ratio of the cross-section obtained by cutting the second terminal portion with the outer surface of the encapsulation body are both 1.4 to 2.

7.

14. The current sensor according to claim 12, wherein, The aspect ratio of the cross-section of the conductor at the connection portion between the first main body portion and the turning portion and the aspect ratio of the cross-section of the conductor at the connection portion between the second main body portion and the turning portion are both 1.4 to 2.

7.

15. The current sensor according to claim 1 or 2, wherein, When the ratio of the long side to the short side of a rectangle is defined as the aspect ratio, The aspect ratio of the cross-section of the connection portion between the first terminal portion and the first main body portion and the aspect ratio of the cross-section of the connection portion between the second terminal portion and the second main body portion are both 1.4 to 2.

7.

16. The current sensor according to claim 1 or 2, wherein, The thickness of the conductor is substantially constant, The width of the cross-section obtained by cutting the first terminal portion with the outer surface of the encapsulation body or the width of the cross-section obtained by cutting the second terminal portion with the outer surface of the encapsulation body is less than the width of the turning portion.

17. The current sensor according to claim 16, wherein, The width of at least one of the connection portion between the first terminal portion and the first main body portion and the connection portion between the second terminal portion and the second main body portion is also less than the width of the connection portion between the first main body portion and the turning portion and the width of the connection portion between the second main body portion and the turning portion.

18. The current sensor according to claim 1 or 2, wherein, The current sensor includes any one of a tunneling magnetoresistance element (TMR), a giant magnetoresistance element (GMR), and an anisotropic magnetoresistance element (AMR).

19. The current sensor according to claim 1 or 2, wherein, The magnetic sensor is composed of a first magnetic sensor and a second magnetic sensor, The first magnetic sensor is disposed on the connection portion between the first main body portion and the turning portion, The second magnetic sensor is disposed on the connection portion between the second main body portion and the turning portion, The first magnetic sensor and the second magnetic sensor each include any one of a tunneling magnetoresistance element (TMR), a giant magnetoresistance element (GMR), and an anisotropic magnetoresistance element (AMR), The first magnetic sensor and the second magnetic sensor have opposite magnetic sensitive directions and are wire-connected to each other.

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