Current sensor

Abstract

To provide a current sensor facilitating failure detection.SOLUTION: The current sensor comprises: a conductor 40 including a first terminal part 41a arranged on one side in a first axial direction for receiving current, a second terminal part 41b for outputting current separating in a second axial direction intersecting the first axial direction from the first terminal part, a turn part 43 arranged on the other side in the first axial direction, a first body part 42a connecting one end of the turn part and the first terminal part, and a second body part 42b separating from the first body part in the second axial direction and connecting the other end of the turn part and the second terminal part; a magnetic sensor 30 arranged on or in the vicinity of the conductor; and a package 10 sealing the turn part, the first body part, the second body part and the magnetic sensor of the conductor and exposing the first terminal part and the second terminal part. At least one of a cross sectional area of a cross section obtained by cutting the first terminal part at an outer surface of the package and a cross sectional area of a cross section obtained by cutting the second terminal part at an outer surface of the package is smaller than a cross sectional area of the turn part.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A current sensor is known in which a conductor through which a current to be measured flows and a magnetoelectric conversion element adjacent to the conductor are sealed in a package, and the strength of a magnetic field generated by the current to be measured flowing through the conductor is detected using the magnetoelectric conversion element and converted into an electrical signal to detect the amount of current. In such a 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 adjacent to the magnetoelectric conversion element inside the package is made smaller than the cross-sectional area of the conductor portion located at the package periphery to increase the current density in the conductor. As a result, there is a concern that when an overcurrent flows due to a failure or the like, the conductor inside the package will overheat, leading to a failure of the sensor. Patent Document 1 discloses an explosive fuse that prevents damage to the sensor by discharging an arc discharge generated along with the overcurrent during a failure to the splitter side. However, it is generally difficult to detect a failure occurring inside the package. [Prior Art Documents] [Patent Documents] [Patent Document 1] International Publication No. 2017 / 136221

Summary of the Invention

Means for Solving the Problems

[0003] In one aspect of the present invention, there is provided a current sensor including: a conductor having a first terminal portion for inputting a current, which is disposed on one side in a first axial direction, and a second terminal portion for outputting the current, which is spaced apart from the first terminal portion in a second axial direction intersecting the first axial direction; a turn portion disposed on the other side in the first axial direction; a first body portion connecting one end of the turn portion and the first terminal portion; and a second body portion connecting the other end of the turn portion and the second terminal portion, which is spaced apart from the first body portion in the second axial direction; a magnetic sensor disposed on or near the conductor; and a package sealing the turn portion, the first body portion, the second body portion, and the magnetic sensor of the conductor and exposing the first terminal portion and the second terminal portion, wherein at least one of a cross-sectional area of a connection portion between the first terminal portion and the first body portion and a cross-sectional area of a connection portion between the second terminal portion and the second body portion is smaller than a cross-sectional area of the turn portion.

[0004] In one aspect of the present invention, there is provided a current sensor including: a conductor having a first terminal portion for inputting a current, which is disposed on one side in a first axial direction, and a second terminal portion for outputting the current, which is spaced apart from the first terminal portion in a second axial direction intersecting the first axial direction; a turn portion disposed on the other side in the first axial direction; a first body portion connecting one end of the turn portion and the first terminal portion; and a second body portion connecting the other end of the turn portion and the second terminal portion, which is spaced apart from the first body portion in the second axial direction; a magnetic sensor disposed on or near the conductor; and a package sealing the turn portion, the first body portion, the second body portion, and the magnetic sensor of the conductor and exposing the first terminal portion and the second terminal portion, wherein at least one of a cross-sectional area of a cross-section of the first terminal portion cut at an outer surface of the package and a cross-sectional area of a cross-section of the second terminal portion cut at the outer surface of the package is smaller than a cross-sectional area of the turn portion, a connection portion between the first body portion and the turn portion and a connection portion between the second body portion and the turn portion have a substantially rectangular shape in a top view, and the magnetic sensor is disposed on at least one of a connection portion between the first body portion and the turn portion and a connection portion between the second body portion and the turn portion.

[0005] A current sensor includes a conductor having a first terminal portion for inputting current and disposed on one side in the first axial direction, a second terminal portion for outputting the current and spaced apart from the first terminal portion in a second axial direction intersecting the first axial direction, a turn portion disposed on the other side in the first axial direction, a first body portion connecting one end of the turn portion and the first terminal portion, and a second body portion spaced apart from the first body portion in the second axial direction and connecting the other end of the turn portion and the second terminal portion; a magnetic sensor disposed on or near the conductor; and a package for encapsulating the turn portion, the first body portion, the second body portion, and the magnetic sensor of the conductor and exposing the first terminal portion and the second terminal portion. At least one of a cross-sectional area of a cross-section of the first terminal portion cut on an outer surface of the package and a cross-sectional area of a cross-section of the second terminal portion cut on the outer surface of the package is smaller than a cross-sectional area of the turn portion. A connection portion between the first body portion and the turn portion and a connection portion between the second body portion and the turn portion have a rectangular shape in top view. The magnetic sensor is disposed on at least one of a connection portion between the first body portion and the turn portion and a connection portion between the second body portion and the turn portion.

[0006] Note that the above summary of the invention does not enumerate all the features of the present invention. Also, sub-combinations of these feature groups can also be inventions.

Brief Description of the Drawings

[0007]

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DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution of the invention.

[0009] FIG. 1 shows, in a top view, the internal configuration of the current sensor 1 according to the present embodiment through the package 10. Here, the vertical direction in the drawing is the longitudinal direction, and the horizontal direction is the lateral direction. The current sensor 1 is a sensor that measures the amount of current to be measured by detecting a magnetic field generated around a conductor 40 through which the current to be measured flows, using a magnetic sensor 30, and includes a package 10, a magnetic sensor 30, a conductor 40, and a plurality of signal terminals 50.

[0010] The package 10 is a member that protects each component of the current sensor 1, seals the turn portion 43 of the conductor 40, the first body portion 42a, the second body portion 42b, the magnetic sensor 30, and the proximal ends of the plurality of signal terminals 50, and exposes the first terminal portion 41a and the second terminal portion 41b from the side surface on one side in the vertical direction (the lower side in the drawing), and exposes the tips of the plurality of signal terminals 50 from the side surface on the other side in the vertical direction (the upper side in the drawing). The package 10 is formed into a flat rectangular parallelepiped by molding using a sealing resin having excellent insulating properties, such as epoxy.

[0011] The magnetic sensor 30 is a sensor that detects a magnetic field generated by the current to be measured flowing through the conductor 40, and includes a substrate 31 and two sensor units 20. The magnetic sensor 30 is disposed on the conductor 40. Although the magnetic sensor 30 is described as including two sensor units 20, it may alternatively include only one of them.

[0012] The substrate 31 is a plate-like member that supports the two sensor units 20, and a plurality of wirings (not shown) are laid on the upper surface thereof. The substrate 31 is formed using, for example, any one of silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), aluminum nitride (AlN), sapphire (Si2O3), silicon carbide (SiC), and diamond.

[0013] FIG. 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 a plurality (four in this example) of magnetoelectric conversion elements 21, 22, 23, and 24 arranged in a Wheatstone bridge (full bridge) circuit. Note that two magnetoelectric conversion elements 21 and 23 or 22 and 24 may be used to form a half-bridge circuit.

[0014] The plurality of magnetoelectric conversion elements 21, 22, 23, and 24 are elements whose electrical characteristics (i.e., magnetic resistance) change according to the intensity of the applied magnetic field. The magnetoelectric conversion elements 21, 22, 23, and 24 are arranged with their magnetic sensing directions oriented in the horizontal direction so as to detect the horizontal magnetic field generated on the conductor 40 when the current to be measured flows in the arrow direction within the conductor 40. However, the magnetic sensing directions of the magnetoelectric conversion elements 21 and 24 are the same, the magnetic sensing directions of the magnetoelectric conversion elements 22 and 23 are the same, and are opposite to the magnetic sensing directions of the magnetoelectric conversion elements 21 and 24. As the plurality of magnetoelectric conversion elements 21, 22, 23, and 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 an alloy containing at least one of Co, Fe, B, Ni, and Si, 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 precisely measured.

[0015] The output voltage V is the differential voltage between the terminal 25 between the magnetoelectric conversion elements 21 and 23 and the terminal 26 between the magnetoelectric conversion elements 22 and 24, and V ∝ R1 × R3 - R2 × R4 holds using the respective magnetic resistances R1, R2, R3, and R4 of the magnetoelectric conversion elements 21, 22, 23, and 24. Thereby, the magnetic sensor 30 can measure the intensity of the magnetic field generated by the current to be measured flowing through the conductor 40, and can measure the amount of the current to be measured.

[0016] The two sensor parts 20 of the magnetic sensor 30 are respectively arranged at the connection part between the first body part 42a and the turn part 43 (the first part 421a of the first body part 42a to be described later) and the connection part between the second body part 42b and the turn part 43 (the first part 421b of the second body part 42b to be described later). As will be described later, these connection parts have a rectangular shape in top view. By arranging the sensor part 20 on them, it becomes possible to concentrate the magnetic field generated by energizing the conductor 40 on the sensor part 20 and detect the current amount with high sensitivity. Note that the connection part may be rectangular or substantially rectangular in top view.

[0017] FIG. 2B shows the definition of the rectangularity representing the degree of rectangular shape of the connection part (the first part 421a of the first body part 42a or the first part 421b of the second body part 42b). Assuming that the contour line of the connection part is represented by a solid line. Using the area Sin of the rectangular region with the largest area arranged inside the contour line of the connection part and the area Sout of the rectangular region with the smallest area arranged outside the contour line of the connection part, which are formed by two parallel sides extending in the horizontal direction and two parallel sides extending in the vertical direction that form a rectangle, the rectangularity is defined as Sin / Sout. 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. By allowing the connection part to be not limited to a rectangular shape in top view but also substantially rectangular, the forming of the lead frame when manufacturing the conductor 40 becomes easy, and the conductor 40 easily adheres to the package 10, preventing peeling between them.

[0018] Note that the sensor part 20 may be configured using a Hall element and may be arranged inside the turn part 43 or in the vicinity of the conductor 40 to detect the vertical magnetic field generated when a current flows through the conductor 40.

[0019] Figure 2C shows the configuration of the current sensor 1' including two magnetic sensors 20a and 20b in a top view. In the current sensor 1', the magnetic sensor 30 is composed of a first magnetic sensor 30a including the sensor part 20a and a second magnetic sensor 30b including the sensor part 20b. The sensor part 20a of the first magnetic sensor 30a is disposed on the connection part (the first part 421a of the first body part 42a to be described later) between the first body part 42a and the turn part 43. The sensor part 20b of the second magnetic sensor 30b is disposed on the connection part (the first part 421b of the second body part 42b to be described later) between the second body part 42b and the turn part 43. Each of the first magnetic sensor 30a and the second magnetic sensor 30b includes a magnetic resistance element such as a tunnel magnetoresistance element (TMR), a giant magnetoresistance element (GMR), or an anisotropic magnetoresistance element (AMR). The first magnetic sensor 30a and the second magnetic sensor 30b have opposite magnetic sensing directions and may be wire-connected to each other. Here, a Wheatstone bridge or a half-bridge circuit may be formed using the magnetic resistance elements 21a and 22b, 22a and 21b having opposite magnetic sensing directions included in the sensor parts 20a and 20b of the first magnetic sensor 30a and the second magnetic sensor 30b (see Fig. 2D). By forming a Wheatstone bridge or a half-bridge circuit using the magnetic resistance elements 21a and 22b, 22a and 21b having opposite magnetic sensing directions included in the first magnetic sensor 30a and the second magnetic sensor 30b, an increase in manufacturing cost can be suppressed compared to employing a tunnel magnetoresistance element (TMR) or a giant magnetoresistance element (GMR) having different sensitivity directions in one magnetic sensor 30.

[0020] The conductor (also called a bus bar) 40 is a conductive member that forms a current path through which the current to be measured flows, and has a first terminal part 41a, a second terminal part 41b, a first body part 42a, a second body part 42b, and a turn part 43.

[0021] The first terminal part 41a is a terminal for inputting the current to be measured (simply referred to as current). The first terminal part 41a includes a plurality (four in this example) of terminals 41a1, 41a2, 41a3, 41a4 disposed on one side in the vertical direction (the lower side of the drawing) and protruding from the lower side surface of the package 10 in the drawing.

[0022] 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 that are spaced apart from the first terminal portion 41a in the right direction of the drawing and protrude from the lower side surface of the package 10 in the drawing. Note that 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.

[0023] The first body portion 42a is a portion that connects one end of the turn portion 43 and the first terminal portion 41a. The first body portion 42a has a shape in which the cross-sectional area increases from the connection portion with the turn portion 43 toward the connection portion with the first terminal portion 41a, and has a first portion (also called an arm portion and also being the connection portion of the first body portion 42a and the turn portion 43) 421a and a second portion 422a. The first portion 421a is a rectangular portion in a top view that connects to the turn portion 43. The second portion 422a connects to the terminal portion 41a and is a portion that widens from the first portion 421a toward the first terminal portion 41a.

[0024] The second body portion 42b is a portion that connects the other end of the turn portion 43 and the second terminal portion 41b, and is arranged spaced apart from the first body portion 42a on the right side of the drawing. The second body portion 42b has a shape in which the cross-sectional area increases from the connection portion with the turn portion 43 toward the connection portion with the second terminal portion 41b, and has a first portion (also being the connection portion of the second body portion 42b and the turn portion 43) 421b and a second portion 422b. The first portion 421b is a rectangular portion in a top view that connects to the turn portion 43. The second portion 422b connects to the terminal portion 41b and is a portion that widens from the first portion 421b toward the first terminal portion 41b.

[0025] The turn portion 43 is a portion that connects to the two body portions 42a and 42b at both of its ends. It is arranged on the other side in the vertical direction (the upper side in the drawing), extends from one side in the vertical direction (the lower side in the drawing) to the other side (the upper side in the drawing), has a shape that bends horizontally and returns to one side, and has a substantially arc shape as an example. Note that the turn portion 43 may be bent in a U shape, an inverted V shape, or a П shape. The measured current is input from the first body portion 42a to the turn portion 43, and the measured current is output to the second body portion 42b.

[0026] By including 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 formed as described above, the conductor 40 has a substantially U shape that starts from the first terminal portion 41a provided on the left side in the drawing on the lower side surface of the package 10, passes through the inside of the package 10, returns to the lower side, and reaches the second terminal portion 41b provided on the right side in the drawing on the lower side surface. The conductor 40 can be formed using a conductive metal such as copper, for example.

[0027] The plurality of signal terminals 50 are members for transmitting the output signal of the magnetic sensor 30 to the secondary circuit 3 (details will be described later). They are separated from the conductor 40 on the upper side in the drawing, and their tips are exposed from the upper side surface in the drawing and sealed in the package 10. The plurality of signal terminals 50 can be formed using a conductive metal such as copper, for example. The plurality of signal terminals 50 are wire-bonded to the magnetic sensor 30. Note that the tip portion exposed from the package 10 is connected to the secondary circuit 3 on the mounting substrate 100 when the current sensor 30 is mounted on the mounting substrate 100.

[0028] Since the conductor 40 has a slight electrical resistance, it generates heat when current flows through it. Here, when an instantaneous overcurrent such as occurs during a fault flows through the conductor 40, the distribution ΔT of the temperature change in the conductor 40 is such that heat dissipation through the package is sufficiently slow and negligible, so for the position r on the conductor 40, it is expressed as follows.

Equation

[0029] FIG. 3 shows the definitions of the cross-sections S41a, S41b, S42a, S42b, and S43 of the conductor 40. The cross-section S41a is the cross-section obtained by cutting the first terminal portion 41a on the outer surface of the package 10, and includes the respective cross-sections S41a1, S41a2, S41a3, and S41a4 of the plurality of terminals 41a1, 41a2, 41a3, and 41a4. The cross-section S41b is the cross-section obtained by cutting the second terminal portion 41b on the outer surface of the package 10, and includes the respective cross-sections S41b1, S41b2, S41b3, and S41b4 of the plurality of terminals 41b1, 41b2, 41b3, and 41b4. The cross-section S42a is the cross-section of the connection portion between the first body portion 42a and the turn portion 43. The cross-section S42b is the cross-section of the connection portion between the second body portion 42b and the turn 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 turn portion 43. The cross-sectional area of the turn portion 43 is given by the area of the cross-section S43.

[0030] Here, 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 S43 of the turn portion 43. Thereby, when measuring the magnetic field generated by energizing the conductor 40 by the magnetic sensor 30 disposed on the conductor 40 to detect the current amount, even if an overcurrent flows, the connection portion of the first terminal portion 41a and the first body portion 42a close to the outer surface of the package 10 or and the connection portion of the second terminal portion 41b and the second body portion 42b, current concentrates and a failure occurs, so that it becomes easy to confirm the failure of the current sensor 1 from outside the package 10.

[0031] Further, at least one of the total cross-sectional areas of cross-sections S41a1 to S41a4 and the total cross-sectional areas of cross-sections S41b1 to S41b4 is determined to be smaller than the cross-sectional area of the turn portion 43. Thereby, the cross-sectional areas of the first body portion 42a and the second body portion 42b are increased to reduce 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 and 41b1 to 41b4 to increase resistance. Even if an overcurrent flows, a current concentrates on any one of the plurality of terminals 41a1 to 41a4 and 41b1 to 41b4 at the connection portion between the first terminal portion 41a and the first body portion 42a and at the connection portion between the second terminal portion 41b and the second body portion 42b that are close to the outer surface of the package 10, causing a failure. Thus, it becomes possible to confirm a failure of the current sensor from outside the package 10.

[0032] Also, at least one of the cross-sectional area of cross-section S41a and the cross-sectional area of cross-section S41b is determined to be smaller than the cross-sectional area of cross-section S42a at the connection portion between the turn portion 43 and the first body portion 42a and the cross-sectional area of cross-section S42b at the connection portion between the turn portion 43 and the second body portion 42b. Thereby, when a current concentrates on at least one of cross-section S41a obtained by cutting the first terminal portion 41a on the outer surface of the package 10 and cross-section S41b obtained by cutting the second terminal portion 41b on the outer surface of the package 10 at the connection portion between the turn portion 43 and the first body portion 42a and at the connection portion between the turn portion 43 and the second body portion 42b, causing the temperature to increase and a failure to occur, it becomes easy to confirm a failure of the current sensor from outside the package 10.

[0033] Here, when an overcurrent that causes a current to concentrate on at least one of cross-sections S41b, increasing the temperature and causing a failure, instantaneously flows through the conductor 40, the current tends to concentrate in the vicinity of the turn portion 43. That is, when an overcurrent instantaneously flows through the conductor 40, the current tends to concentrate and become hot in the vicinity of the turn portion 43 next to the first terminal portion 41a outside the package 10. In the present invention, the sensor unit 20 is arranged not on the turning part 43 but at the connection part between the first body part 42a and the turning part 43 (the first part 421a of the first body part 42a described later) and at the connection part between the second body part 42b and the turning part 43 (the first part 421b of the second body part 42b described later). By doing so, while preventing thermal destruction of the sensor in case of a failure, it becomes possible to detect the current amount with high sensitivity.

[0034] Fig. 3 further 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 part 41a on 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 part 41b on 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 connection part between the first body part 42a and the turning part 43. The width L42b is the width of the connection part between the second body part 42b and the turning part 43. The width L43 is the width on the central axis of the conductor 40 parallel to the longitudinal direction in the turning part 43.

[0035] 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 part 41a on the outer surface of the package 10 and the width L41b of the cross-section S41b obtained by cutting the second terminal part 41b on the outer surface of the package 10 is determined to be smaller than the width L43 of the turning part 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 part 41a on the outer surface of the package 10 and the cross-sectional area of the cross-section S41b obtained by cutting the second terminal part 41b on the outer surface of the package 10 is smaller than the cross-sectional area of the cross-section S43 of the turning part 43. Therefore, it is possible to configure such that a failure can be confirmed at the first terminal part 41a or the second terminal part 41b instead of the turning part 43.

[0036] Further, at least one of the width L41a of the cross-section S41a obtained by cutting the first terminal portion 41a on the outer surface of the package 10 and the width L41b of the cross-section S41b obtained by cutting the second terminal portion 41b on the outer surface of the package 10 is further defined to be smaller than the width L42a of the connection portion between the first body portion 42a and the turn portion 43 and the width L42b of the connection portion between the second body portion 42b and the turn portion 43. Thereby, 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 on 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 on the outer surface of the package 10 is smaller than the cross-sectional area of the cross-section S42a of the connection portion between the turn portion 43 and the first body portion 42a and the cross-sectional area of the cross-section S42b of the connection portion between the turn portion 43 and the second body portion 42b, and a configuration can be achieved in which a failure can be confirmed at the first terminal portion 41a or the second terminal portion 41b, rather than at the turn portion 43, the connection portion between the first body portion 42a and the turn portion 43, or the connection portion between the second body portion 42b and the turn portion 43.

[0037] The measured current flowing through the conductor 40 is not limited to a direct current, but may also be an alternating current. When the measured current is an alternating current, a skin effect occurs in the conductor 40. The skin effect is a phenomenon in which when an alternating current flows through the conductor 40, the higher the frequency of the current, the more the current concentrates near the surface of the conductor 40, and the farther away from the surface of the conductor 40, the more difficult it is for the current to flow, and the temperature inside the conductor 40 rises. Therefore, by increasing the surface ratio with respect to the cross-sectional area of each part of the conductor 40, it is possible to prevent an increase in the resistance of each part even when the skin effect is caused by a high-frequency current.

[0038] FIG. 4A shows the definitions of the cross-sections S43, S41a, S41b, S42a, and S42b of the conductor 40.

[0039] Fig. 4B shows the relationship between the aspect ratio and the resistance fluctuation rate due to the skin effect with the case where the aspect ratio is 1 as a reference when the cross-section of the conductor 40 is rectangular and the aspect ratio is the ratio of the long side to the short side. When the conductor is made of copper, the skin thickness 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) and the resistance R(f) for a direct current and an alternating current with a frequency f are R(0) ∝ 1 / (t×W) and R(f) ∝ 1 / (2(t + W)δ). Therefore, the resistance increase rate 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, t = √(S / A) and W = √(S×A), so the fluctuation rate of the resistance increase due to the skin effect with the aspect ratio A = 1 as a reference 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 resistance increase due to the skin effect can be suppressed.

[0040] Cross-section S43 is the cross-section of the conductor 40 at the turn 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 turn portion 43. When the thickness of the conductor 40 is substantially constant, the length of the short side of the cross-section S43 is equal to the length of the short sides of the cross-sections S42a and S42b and the length of the long sides of the cross-sections S41a1 to S41a4 and S41b1 to S41b4. When the aspect ratio is defined as the long side / short side with respect to the long side and the short side of the rectangular cross-section, 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 turn portion 43, the resistance at the turn portion 43 is not increased for the alternating current that causes the skin effect, and the temperature change can be suppressed compared to the first terminal portion 41a or the second terminal portion 41b. By setting the aspect ratio of the cross-section S43 to 1.4, the resistance increase rate due to the skin effect can be reduced by 1%. More preferably, by setting the aspect ratio to 2.0, the resistance increase rate due to the skin effect can be reduced by 6%. Even more preferably, by setting the aspect ratio to 2.5, the resistance increase rate due to the skin effect can be reduced by 10%. However, if the aspect ratio is made larger than 2.7, the package size increases and the difficulty of processing increases, which is not preferable.

[0041] As described above, the cross-section S41a is the cross-section of the conductor 40 obtained by cutting the first terminal portion 41a on the outer surface of the package 10 (see FIG. 3). The length of the short side of each of the cross-sections S41a1, S41a2, S41a3, and S41a4 of the plurality of terminals 41a1, 41a2, 41a3, and 41a4 is equal to the top-view width L41a1 to L41a4 of each of the plurality of terminals 41a1 to 41a4, and the length of the long side is equal to the thickness of the conductor 40. When the thickness of the conductor 40 is substantially constant, the long sides of the cross-sections S41a1 to S41a4 are equal to the length of the short sides of the cross-sections S43, S42a, and S42b and the length of the long sides of the cross-sections S41b1 to S41b4.

[0042] As described above, cross-section S41b is the cross-section of conductor 40 obtained by cutting the second terminal portion 41b on the outer surface of package 10. The length of the short side of each of the cross-sections S41b1, S41b2, S41b3, S41b4 of the plurality of terminals 41b1, 41b2, 41b3, 41b4 is equal to the top-view width L41b1 to L41b4 of each of the plurality of terminals 41b1 to 41b4, and the length of the long side is equal to the thickness of conductor 40. When the thickness of conductor 40 is substantially constant, the long sides of cross-sections S41b1 to S41b4 are equal to the length of the short sides of cross-sections S43, S42a, S42b and the length of the long sides of cross-sections S41a1 to S41a4.

[0043] Since the aspect ratios of cross-sections S41a and S41b are both 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 the alternating current causing the skin effect, the resistance at the first terminal portion 41a and the second terminal portion 41b is not increased, and it is possible to prevent the first terminal portion 41a or the second terminal portion 41b from being excessively prone to failure. Note that by setting the aspect ratios of cross-sections S41a1 to S41a4 and S41b1 to S41b4 to 1.4, the resistance increase rate due to the skin effect can be reduced by 1%. More preferably, by setting the aspect ratio to 2.0, the resistance increase rate due to the skin effect can be reduced by 6%. Even more preferably, by setting the aspect ratio to 2.5, the resistance increase rate due to the skin effect can be reduced by 10%. However, if the aspect ratio is made larger than 2.7, the package size increases and the difficulty of processing increases, which is not preferable.

[0044] As described above, cross-section S42a is the cross-section of conductor 40 at the connection portion of the first body portion 42a and the turn portion 43. The length of the short side of cross-section S42a is equal to the thickness of conductor 40, and the length of the long side is equal to the width L42a of the connection portion of the turn portion 43 and the first body portion 42a. When the thickness of conductor 40 is substantially constant, the length of the short side of cross-section S42a is equal to the length of the short sides of cross-sections S43, S42b and the length of the long sides of cross-sections S41a1 to S41a4, S41b1 to S41b4.

[0045] As described above, the cross-section S42b is the cross-section of the conductor 40 at the connection portion between the second body portion 42b and the turn portion 43 (see FIG. 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 connection portion between the turn portion 43 and the second body portion 42b. The short side of the cross-section S42b is equal to the length of the short sides of the cross-sections S43 and S42a and the long sides of the cross-sections S41a1 to S41a4 and S41b1 to S41b4 when the thickness of the conductor 40 is substantially constant.

[0046] Since the aspect ratios of the cross-sections S42a and S42b are both 1.4 to 2.7, the surface area with respect to the area of the connection portion between the first body portion 42a and the turn portion 43 of the second body portion 42b increases, and even for the alternating current that causes the skin effect of the cross-section S42b, the resistance in the turn portion 43, the first body portion 42a, or the second body portion 42b is not increased, and the temperature change can be suppressed from the first terminal portion 41a or the second terminal portion 41b. However, when the aspect ratio of the cross-sections S42a and S42b is less than 1.4, the increase in resistance due to the skin effect cannot be sufficiently prevented, and when it exceeds 2.7, the current sensor 1 cannot be made small in order to ensure the withstand voltage between the first part 421 of the body portion and the signal terminal 50.

[0047] FIG. 4C 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 increases and the skin effect occurs, the resistance does not increase significantly. The broken 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 increases, the resistance increases due to the occurrence of the skin effect. The thick line is the relationship between the resistance and the frequency in the turn portion 43 of the conductor 40. The thin line is the relationship between the resistance and the frequency in the turn portion 43 of the conductor 40 and the relationship between the resistance and the frequency in the terminal portions 41a and 41b. By increasing the surface ratio of each part of the conductor 40 with respect to the cross-sectional area, the increase in resistance with respect to the frequency can be suppressed. Since the resistance of the turn portion 43 and the terminal portions 41a and 41b is less likely to increase with the frequency, failures of each part of the conductor 40 can be suppressed even when a high-frequency alternating current flows as an overcurrent.

[0048] Figures 4D and 4E show current sensors with different aspect ratios of the cross-section S43 of the turn portion 43 in a top view. When the aspect ratio of the turn portion 43 increases, the width of the turn portion 43 increases. If the size of the package 10 remains unchanged, the separation distance between the turn portion 43 and the signal terminal 50 decreases, so the dielectric withstand voltage between the turn portion 43 and the signal terminal 50 cannot be ensured. Therefore, when the aspect ratio of the turn portion 43 increases, the package 10 becomes larger and the current sensor 1 becomes larger in order to maintain the separation distance between the turn portion 43 and the signal terminal 50 and ensure the dielectric withstand voltage.

[0049] Figure 5A shows the configuration of the mounting substrate 100 on which the current sensor 1 is mounted in a top view. The mounting substrate 100 is a substrate including the current sensor 1, the primary circuit 2, and the secondary circuit 3. In the mounting substrate 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. Note that 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 according to the output signal of the current sensor 1, and includes a plurality of footprints 70 respectively connected to a plurality of circuits (not shown). The plurality of footprints 70 are respectively connected to a plurality of signal terminals 50 (see 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 footprints 70 include the footprint 71 and the footprint 72.

[0052] The footprint 71 is at least one of the plurality of footprints 70, and is connected to the signal terminal 51 among the plurality of signal terminals 50 (see Figure 5B).

[0053] The footprint 72 is the remaining footprint excluding the footprint 71 among the plurality of footprints 70, and is connected to the signal terminal 52 among the plurality of signal terminals 50 (see FIG. 5B).

[0054] FIG. 5B shows, in a top view, the arrangement of the current sensor 1 and the plurality of footprints 70 and the definitions of the distances L51, L51', L50, and L50'. As described above, the signal terminal 51 and the signal terminal 52 (see FIG. 5B) among the plurality of signal terminals 50 are connected to the footprint 71 and the footprint 72 among the plurality of footprints 70, respectively. The distance L51 is the separation distance between the signal terminal 51 and the turn portion 43 of the conductor 40. The distance L51' is the separation distance between the signal terminal 51 and the body portion 42 of the conductor 40. The distance L50 is the separation distance between the other signal terminal 52 and the turn portion 43 of the conductor 40. The distance L50 may be the minimum value of the separation distances between each of the other signal terminals 52 and the turn portion 43. The distance L50' is the separation distance between the other signal terminal 52 and the body portions 42a and 42b of the conductor 40. The distance L50' may be the minimum value of the separation distances between each of the other signal terminals 52 and the body portions 42a and 42b.

[0055] In the above arrangement, the distance L51 is shorter than the distance L50. In other words, the signal terminal 51 is closer to the turn portion 43 than the other signal terminals 52. Thereby, the heat generated at the turn portion 43 can be dissipated outside the package 10 through the signal terminal 51 close to the turn portion 43 among the plurality of signal terminals 50. The distance L51 between the turn portion 43 and the signal terminal 51 is preferably 0.4 mm or more in order to ensure insulation. Note that the signal terminal 51 may be a GND terminal. When an arc discharge occurs at the turn portion 43, since the signal terminal 51 close to the turn portion 43 is a GND terminal, discharge can be induced from the signal terminal 51 close to the GND, and damage to the plurality of circuits on the secondary circuit 3 to which the other signal terminals 52 are connected can be suppressed.

[0056] Furthermore, 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 turn portion 43 or the first body portion 42a or the second body portion 42b than the other signal terminals 52 included in the plurality of signal terminals 50. Thus, since the signal terminal 51 closest to the turn portion 43, the first body portion 42a, and the second body portion 42b is the GND terminal, when an arc discharge occurs in the turn portion 43 or the body portion 42, discharge is induced from the adjacent signal terminal 51 to the GND, suppressing damage to the plurality of circuits on the secondary circuit 3 to which the other signal terminals 52 are connected.

[0057] When the current 1 sensor is mounted on the mounting substrate 100, the signal terminal 51 is connected to the footprint 71 on the mounting substrate 100 that has a larger area than the footprint 72 to which the other signal terminals 52 are connected. Thus, by connecting the signal terminal 51 to the footprint 71 on the mounting substrate that has a larger area than the footprint 72 to which the other signal terminals 52 are connected, the signal terminal 51 to which heat is transferred from the turn portion 43 can dissipate heat efficiently with a larger heat dissipation area, improving the heat dissipation performance of the turn portion 43 and preventing failures due to heat accumulation. The footprint 71 preferably has an area 1.5 to 40 times that of the other footprint 72.

[0058] Fig. 6A shows the arrangement of the conductor 40, the insulating layer 80, and the magnetic sensor 30 in a 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 using, for example, a polyimide layer, glass, paper, Teflon (registered trademark), or silicon.

[0059] The magnetic sensor 30 is disposed on the conductor 40 via the insulating layer 80, 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. For ensuring insulation, it is preferable that the contour line of the insulating layer 80 is at a distance of 0.4 mm or more outward from the contour line of the magnetic sensor 30. Thereby, 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 reduce the heat dissipation property of the conductor 40 without inhibiting the heat dissipation of the conductor 40.

[0060] FIGS. 6B and 6C show the arrangement of the conductor 40, the insulating layer 80, and the magnetic sensor 30 in the cross-section A-A' of FIG. 6A in a side view. As shown in FIG. 6B, 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 shown in FIG. 6C, 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 secure a sufficiently large heat dissipation surface, and the heat dissipation property is inhibited.

[0061] FIGS. 7A to 7F show the configurations of the current sensors 1A, 1B, 1C, 1D, 1E, and 1F in each modification in a top view.

[0062] FIG. 7A shows the configuration of the current sensor 1A according to the first modification. Note that the reference numerals are omitted for the configurations common to FIG. 1. The current sensor 1A includes an inverted U-shaped turn portion 43 and body portion first parts 421a, 421b, and a magnetic sensor 30A disposed on the body portion first parts 421a, 421b and having a substrate 31A extending on the turn portion 43 and the vertical width of the substrate 31A being longer than the length of the body portion first parts 421a, 421b. By the substrate of the magnetic sensor 30A extending on the turn portion 43, the substrate approaches the signal terminal 50, facilitating the wire bonding of the signal terminal 50 and improving the manufacturability.

[0063] FIG. 7B shows the configuration of the current sensor 1B according to the second modification. Note that the components common to FIG. 1 are not given reference numerals. The current sensor 1B includes an inverted U-shaped turn portion 43 and body portion first parts 421a and 421b, and a magnetic sensor 30 disposed on the body portion first parts 421a and 421b and having a substrate 31B extending onto body portion second parts 422a and 422b, the longitudinal width of the substrate 31B being longer than the length of the body portion first parts 421a and 421b. Since the substrate 31B of the magnetic sensor 30 extends onto the body portion second part 422, the substrate is moved away from the turn portion 43 which is a heat generating location, so that the temperature rise of the substrate 31B of the magnetic sensor 30 can be suppressed, and the reliability of current measurement is improved.

[0064] FIG. 7C shows the configuration of the current sensor 1C according to the third modification. Note that the components common to FIG. 1 are not given reference numerals. The current sensor 1C includes body portion first parts 421aC and 421bC which are as short as possible and shorter than the substrate 30, a substantially arc-shaped turn portion 43C, and a magnetic sensor 30 spanning over the shortened body portion first parts 421aC and 421bC. By shortening the body portion first parts 421aC and 421bC as much as possible, the resistance of the conductor 40C can be reduced and the temperature change can be suppressed. By connecting the turn portion 43C at the location where the flow path from the body portion second parts 422aC and 422bC is the narrowest, the current density can be increased and the current can be aligned in the vertical direction to strengthen the magnetic field generated by the current to be measured, and a function similar to that of the body portion first parts 421aC and 421bC can be obtained in the dashed line portion in the figure.

[0065] FIG. 7D shows the configuration of the current sensor 1D according to the fourth modification. Note that the components common to FIG. 1 are not given reference numerals. The current sensor 1D includes a U-shaped turn portion 43D and body portion first parts 421aD and 421bD, and a magnetic sensor 30 on the body portion first parts 421aD and 421bD. By forming the turn portion 43D and the body portion first parts 421aD and 421bD in a U-shape, the processing of the conductor 40D becomes easy and the design of the signal terminal 50 also becomes easy.

[0066] Fig. 7E shows the configuration of the current sensor 1E according to the fifth modification. Note that the reference numerals are omitted for the configurations common to Fig. 1. The current sensor 1E includes an inverted V-shaped turn portion 43E, first body portions 421aE and 421bE, and a magnetic sensor 30 on the first body portions 421aE and 421bE. By forming the turn portion 43E and the first body portions 421aE and 421bE in an inverted V shape, the turn portion 43E can be designed to be small.

[0067] Fig. 7F shows the configuration of the current sensor 1F according to the sixth modification. Note that the reference numerals are omitted for the configurations common to Fig. 1. The current sensor 1F includes a П-shaped turn portion 43F, a first body portion 421F, and a magnetic sensor 30 on the first body portions 421aF and 421bF. By forming the turn portion 43F and the first body portions 421aF and 421bF in a П shape, the top-view area of the turn portion 43F can be increased, and the heat dissipation of the turn portion 43F can be improved.

[0068] As described above, the current sensor 1 according to the present embodiment includes a first terminal portion 41a for inputting a current, which is disposed on one side in the first axial direction, and a second terminal portion 41b for outputting a current that is separated from the first terminal portion 41a in the second axial direction intersecting the first axial direction. A turn portion 43 is disposed on the other side in the first axial direction, a first body portion 42a connecting one end of the turn portion and the first terminal portion 41a, and a second body portion 42b that is separated from the first body portion 42a in the second axial direction and connects the other end of the turn portion 43 and the second terminal portion 41b. A conductor 40 having the above, a magnetic sensor 30 disposed on or near the conductor 40, and a package 10 that seals the turn portion 43, the first body portion 42a, the second 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. At least one of the area of the cross section S41a obtained by cutting the first terminal portion 41a on the outer surface of the package 10 and the area of the cross section S41b obtained by cutting the second terminal portion 41b on the outer surface of the package 10 is smaller than the area of the cross section S43 of the turn portion 43. According to this, since the areas of the respective cross sections S41a and S41b of the first terminal portion 41a and the second terminal portion 41b close to the outer surface of the package 10 among the conductor 40 are smaller than the area of the cross section S43 of the turn portion 43 disposed inside the package 10, even if an overcurrent flows when measuring the magnetic field generated by energizing the conductor 40 by the magnetic sensor 30 disposed on or near the conductor 40 to detect the current amount, the current concentrates on the first terminal portion 41a or and the second terminal portion 41b close to the outer surface of the package 10 and a failure occurs, it becomes easy to confirm the failure of the current sensor 1 from outside the package 10.

[0069] As described above, the present invention has been described using embodiments. However, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

[0070] In the claims, the specification, and the drawings, for the operations, procedures, steps, stages, and other processes in the apparatus, system, program, and method shown, the execution order of each process, such as the operations, procedures, steps, and stages, etc., is not explicitly stated as "earlier than", "preceding", etc. in particular, and it should be noted that it can be realized in any order as long as the output of the previous process is not used in the subsequent process. Regarding the operation flows 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 is essential to be implemented in this order.

Explanation of Reference Signs

[0071] 1, 1', 1A, 1B, 1C, 1D, 1E, 1F, 1G... current sensors, primary circuit... 2, secondary circuit... 3, 10... packages, 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... conductors, 41a, 41b... terminal parts, 41a1, 41a 2、 41a 3、 41a4, 41b1, 41b2, 41b 3、 41b4... terminals, 42a, 42b... body parts, 421a, 421b... first parts of the body, 422a, 422b... second parts of the body, 43... turn parts, 50, 51, 52... signal terminals, 70, 71, 72... footprints, 80... insulating layer, mounting substrate... 100, L41a, L41a1, L41a 2、 L41a 3、 L41a4, L41b, L41b1, L41b2, L41b3, L41b4, L42a, L42b, L43... widths, L50, L50', L51, L51'... distances, S41a, S41a1, S41a 2、 S41a 3、 S41a4, S41b, S41b1, S41b 2、 S41b 3、 S41b4, S42a, S42b, S43... cross-sections

Claims

1. A conductor having a first terminal portion for inputting current, which is disposed on one side in the first axial direction, and a second terminal portion for outputting the current, which is spaced apart from the first terminal portion in a second axial direction intersecting the first axial direction, a turn portion disposed on the other side in the first axial direction, a first body portion connecting one end of the turn portion and the first terminal portion, and a second body portion connecting the other end of the turn portion and the second terminal portion, which is spaced apart from the first body portion in the second axial direction; A magnetic sensor disposed on or near the conductor; 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; and At least one of the cross-sectional area of the cross-section of the first terminal portion cut on the outer surface of the package and the cross-sectional area of the cross-section of the second terminal portion cut on the outer surface of the package is smaller than the cross-sectional area of the turn portion; The connection portion between the first body portion and the turn portion and the connection portion between the second body portion and the turn portion have a substantially rectangular shape in a top view; The magnetic sensor is disposed on at least one of the connection portion between the first body portion and the turn portion and the connection portion between the second body portion and the turn portion; A current sensor.

2. A conductor having a first terminal portion for inputting current, which is disposed on one side in the first axial direction, and a second terminal portion for outputting the current, which is spaced apart from the first terminal portion in a second axial direction intersecting the first axial direction, a turn portion disposed on the other side in the first axial direction, a first body portion connecting one end of the turn portion and the first terminal portion, and a second body portion connecting the other end of the turn portion and the second terminal portion, which is spaced apart from the first body portion in the second axial direction; A magnetic sensor disposed on or near the conductor; 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; and At least one of the cross-sectional area of the cross-section of the first terminal portion cut on the outer surface of the package and the cross-sectional area of the cross-section of the second terminal portion cut on the outer surface of the package is smaller than the cross-sectional area of the turn portion; The connection portion between the first body portion and the turn portion and the connection portion between the second body portion and the turn portion have a rectangular shape in a top view; The magnetic sensor is disposed on at least one of the connection portion between the first body portion and the turn portion and the connection portion between the second body portion and the turn portion. Current sensor. **Claim 3** The first body portion has a shape in which the cross-sectional area increases from the connection portion with the turn portion toward the connection portion with the first terminal portion, and the second body portion has a shape in which the cross-sectional area increases from the connection portion with the turn portion toward the connection portion with the second terminal portion. The first terminal portion and the second terminal portion each include a plurality of terminals. The current sensor according to claim 1 or 2, wherein at least one of the total cross-sectional areas of the cross-section of the first terminal portion cut on the outer surface of the package and the cross-section of the second terminal portion cut on the outer surface of the package is smaller than the cross-sectional area of the turn portion. **Claim 4** The turn portion extends from one side to the other side in the first axial direction and has a shape that bends in the second axial direction and returns to the one side. The current sensor according to claim 1 or 2, wherein the cross-sectional area of the turn portion is given by the cross-sectional area on the central axis of the conductor parallel to the first axial direction. **Claim 5** The current sensor according to claim 1, wherein at least one of the cross-sectional area of the cross-section of the first terminal portion cut on the outer surface of the package and the cross-sectional area of the cross-section of the second terminal portion cut on the outer surface of the package is smaller than the minimum value of the cross-sectional area of the connection portion between the turn portion and the first body portion and the minimum value of the cross-sectional area of the connection portion between the turn portion and the second body portion. **Claim 6** The current sensor according to claim 2, wherein at least one of the cross-sectional area of the cross-section of the first terminal portion cut on the outer surface of the package and the cross-sectional area of the cross-section of the second terminal portion cut on the outer surface of the package is smaller than the cross-sectional area of the connection portion between the turn portion and the first body portion and the cross-sectional area of the connection portion between the turn portion and the second body portion. **Claim 7** The current sensor further includes a plurality of signal terminals that are separated from the conductor on one side in the first axial direction, have exposed tips, and are sealed in the package. The current sensor according to claim 1 or 2, wherein at least one of the plurality of signal terminals is closer to the turn portion than the other signal terminals. **Claim 8** The current sensor according to claim 7, wherein the at least one signal terminal is a GND terminal. **Claim 9** The current sensor according to claim 8, wherein the at least one signal terminal is closer to the turn portion, the first body portion, and the second body portion than the other signal terminals. **Claim 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 a footprint on the mounting substrate having an area larger than the footprint to which the other signal terminals are connected.

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

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

7.

13. The current sensor according to claim 12, wherein the aspect ratio in a cross section obtained by cutting the first terminal portion on an outer surface of the package and the aspect ratio in a cross section obtained by cutting the second terminal portion on the outer surface of the package are both 1.4 to 2.

7.

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

7.

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

7.

16. The thickness of the conductor is substantially constant, The current sensor according to claim 1 or 2, wherein at least one of a width of a cross section obtained by cutting the first terminal portion on an outer surface of the package and a width of a cross section obtained by cutting the second terminal portion on the outer surface of the package is smaller than a width of the turn portion.

17. The current sensor according to claim 16, wherein at least one of a width of a connection portion between the first terminal portion and the first body portion and a width of a connection portion between the second terminal portion and the second body portion is further smaller than a width of a connection portion between the first body portion and the turn portion and a width of a connection portion between the second body portion and the turn portion.

18. The current sensor according to claim 1 or 2, wherein the current sensor includes a magnetoresistive element such as a tunnel magnetoresistive element (TMR), a giant magnetoresistive element (GMR), and an anisotropic magnetoresistive element (AMR).

19. The magnetic sensor includes a first magnetic sensor and a second magnetic sensor, The first magnetic sensor is disposed on a connection portion between the first body portion and the turn portion. The second magnetic sensor is disposed on a connection portion between the second body portion and the turn portion. Each of the first magnetic sensor and the second magnetic sensor includes a magnetoresistive element of any one of a tunnel magnetoresistive element (TMR), a giant magnetoresistive element (GMR), and an anisotropic magnetoresistive element (AMR). The current sensor according to claim 1 or 2, wherein the first magnetic sensor and the second magnetic sensor have magnetosensing directions opposite to each other and are wire-connected to each other.

Images