Magnetic sensor and current sensor

Abstract

To suppress a common-mode voltage caused by a magnetic field distribution.SOLUTION: A magnetic sensor 50 comprises a first magnetoelectric conversion part 50a including a resistor side Ra, a resistor side Rb, a resistor side Rc, and a resistor side Rd, each of which is formed by series connecting a plurality of magnetic resistance elements 51. In the first magnetoelectric conversion part 50a, magneto-sensitive directions of the resistor side Ra and the resistor side Rd are equal to each other while magneto-sensitive directions of the resistor side Rb and the resistor side Rc are equal to each other and opposite to the magneto-sensitive directions of the resistor side Ra and the resistor side Rd; the resistor side Ra and the resistor side Rb are series connected, the resistor side Rc and the resistor side Rd are series connected and parallel connected to the resistor side Ra and the resistor side Rb, all of which are assembled in a Wheatstone bridge circuit, at least part of which is arranged on an arm 24c1 included in a conductor 24. The width w of the first magnetoelectric conversion part 50a is 0.3 times of the width W of the arm 24c1 or less. A common-mode voltage Vcm included in an output voltage can thus be suppressed.SELECTED DRAWING: Figure 8A

Description

[Technical field]

[0001] The present invention relates to a magnetic sensor and a current sensor. [Background technology]

[0002] A magnetic sensor is known that includes a Wheatstone bridge circuit composed of four resistance arms each including a magnetoresistance element (TMR), and detects magnetic field strength by inputting a drive voltage from a pair of power supply nodes and acquiring a differential voltage from a pair of output nodes (see Patent Documents 1 and 2). In such a magnetic sensor, the DC voltage resistance and ESD voltage resistance of the magnetic sensor can be improved by configuring each resistance arm by connecting multiple TMRs in series. However, the chip area (equal to the area of ​​the magnetic sensing part) becomes larger, that is, the closed loop formed by the four resistance arms becomes larger, and there is a concern that not only will an induced electromotive force be generated by the passage of a large amount of magnetic flux inside the closed loop, resulting in di / dt noise, but also that a common-mode signal will be generated due to the magnetic field distribution on the magnetic sensing part, resulting in differential amplification noise. Patent Document 1: International Publication No. 2015 / 107949 Patent Document 2: U.S. Patent Application Publication No. 2020 / 0018780 Summary of the Invention [Means for solving the problem]

[0003] In a first aspect of the present invention, there is provided a first magneto-electric conversion unit including a first resistor side, a second resistor side, a third resistor side, and a fourth resistor side, each formed by connecting a plurality of magnetoresistance elements in series, wherein the magnetic sensing directions of the first resistor side and the fourth resistor side are equal to each other, the magnetic sensing directions of the second resistor side and the third resistor side are equal to each other and are opposite to the magnetic sensing directions of the first resistor side and the fourth resistor side, the first resistor side and the second resistor side are connected in series, and the third resistor side and the fourth resistor side are connected in series and are connected in parallel to the first resistor side and the second resistor side. The magnetic sensor includes a first magneto-electric converter arranged on a first arm having at least a portion included in a conductor, the first magneto-electric converter being arranged in a Wheatstone bridge circuit configuration, and the first magneto-electric converter is arranged on a first arm having at least a portion included in a conductor, and the width of the first magneto-electric converter, which is the distance between the center of gravity of the unit area of ​​the resistive side located on the furthest side in the width direction of the first arm and the center of gravity of the unit area of ​​the resistive side located on the furthest side in the width direction of the first arm, among unit areas in which at least some of the magneto-resistive elements forming the first resistive side to the fourth resistive side are arranged adjacent to each other in the width direction, is 0.3 times or less the width of the first arm.

[0004] In a second aspect of the present invention, there is provided a current sensor including a conductor through which a current to be measured flows and the magnetic sensor of the first aspect.

[0005] The above summary of the invention does not list all of the features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0006] [Figure 1A] 1 shows an internal configuration of a current sensor according to the present embodiment as viewed from above. [Figure 1B] 1 shows an internal configuration of a current sensor according to the present embodiment as viewed from the side. [Diagram 2] The circuit configuration of the magnetic sensor (magnetic-electric conversion section) is shown. [Diagram 3] 2 shows the configuration of a magnetoresistive element in side view. [Figure 4A] 2 shows an example of the arrangement of magnetic sensors for detecting a horizontal magnetic field. [Figure 4B] 4B shows the circuit configuration of the first magneto-electric conversion unit and the magnetic field detection direction of the magnetoresistive element in FIG. 4A. [Figure 4C] 4B shows a circuit configuration of the second magnetoelectric conversion unit and a magnetic field detection direction of a magnetoresistance element in FIG. 4A. [Figure 5A] 2 shows an example of the arrangement of magnetic sensors for detecting a vertical magnetic field. [Figure 5B] 5B shows the circuit configuration of the first magneto-electric conversion unit and the magnetic field detection direction of the magnetoresistive element in FIG. 5A. [Figure 5C] 5B shows a circuit configuration of the second magnetoelectric conversion unit and a magnetic field detection direction of a magnetoresistance element in FIG. 5A. [Figure 6A] This shows the principle of di / dt noise generation associated with induced electromotive force. [Figure 6B] This shows the principle of suppressing di / dt noise by twisting wiring. [Figure 7A] 2 shows a planar array of multiple magnetoresistance elements. [Figure 7B] 3 shows a three-dimensional array of multiple magnetoresistance elements. [Figure 8A] 3 shows an arrangement of unit areas in a first magneto-electric transducer. [Figure 8B] 4 shows an arrangement of unit areas in a second magneto-electric transducer. [Figure 9] The magnetic field strength versus position on the conductor and the common-mode voltage output from the magnetoelectric converter are shown. [Figure 10] 1 shows the common-mode voltage output from the magnetoelectric converter versus the ratio of the width of the magnetoelectric converter to the width of the conductor. [Figure 11A] 1 shows a state of a lead frame forming step in the manufacturing flow of the current sensor. [Figure 11B] 1 shows a state of a die bonding process in the manufacturing flow of the current sensor. [Figure 11C] 1 shows a state of a wire bonding process in the manufacturing flow of the current sensor. [Figure 11D] 1 shows a state of a molding process in the manufacturing flow of the current sensor. [Figure 12A] 13 illustrates an internal configuration of a current sensor according to a modified example, as viewed from above. [Figure 12B] 13 shows a side view of an internal configuration of a current sensor according to a modified example. [Figure 13A] 11 shows a state of a lead frame forming step in the manufacturing flow of the current sensor according to the modified example. [Figure 13B] 11 shows a state of a magnetic sensor installation step in the manufacturing flow of the current sensor according to the modified example. [Figure 13C] 11 shows a state of a wire bonding process in the manufacturing flow of a current sensor according to a modified example. [Figure 13D] 11 shows a state of a molding step in the manufacturing flow of the current sensor according to the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0008] 1A and 1B show the internal configuration of the current sensor 100 according to the present embodiment in a top view and a side view, respectively, through the package 9. Here, FIG. 1B shows a cross-sectional structure of the current sensor 100 with respect to the reference line BB in FIG. 1A. The up-down direction in FIG. 1A is the vertical direction, the left-right direction in FIG. 1A and FIG. 1B is the horizontal direction, and the up-down direction in FIG. 1B is the height direction. The current sensor 100 is a sensor that measures the amount of current by detecting a magnetic field generated around a conductor 24 when a current to be measured flows through the conductor 24 using a magnetic sensor 50, and can particularly suppress di / dt noise due to induced electromotive force and / or differential amplification noise associated with the spread of the magnetic field distribution. The current sensor 100 includes a package 9, a base 10, a plurality of device terminals 17, a conductor 24, a magnetic sensor 50, and a signal processing device 44.

[0009] The package 9 is a member that seals and protects each component of the current sensor 100, except for two device terminals 15 and 16, a plurality of device terminals 17, and each terminal portion of the conductor 24, which are provided on the base 10 and will be described later. The package 9 is molded into a flat rectangular parallelepiped by using a sealing resin with excellent insulating properties, such as epoxy.

[0010] The base 10 is a plate-like member that supports the signal processing device 44. The base 10 is formed into a plate shape using, for example, a metal with high thermal conductivity in order to dissipate heat generated particularly by the signal processing device 44. The base 10 has a main body 11, protrusions 12 and 14, and device terminals 15 and 16.

[0011] The main body 11 is a portion that supports the signal processing device 44. The main body 11 has, for example, a substantially rectangular shape large enough to support the signal processing device 44 in a plan view.

[0012] The protrusions 12 and 14 extend rightward from one end (i.e., the upper end in FIG. 1A) and the other end (i.e., the lower end in FIG. 1A) of one horizontal side (i.e., the right side in FIG. 1A) of the main body 11. When the magnetic sensor 50 is disposed around the conductor 24, an insulating member can be fixed between the protrusions 12 and 14, and the magnetic sensor 50 can be disposed on the insulating member.

[0013] The device terminals 15, 16 are portions for outputting the detection result of the current under measurement output from the signal processing device 44 to an external device. The device terminals 15, 16 extend leftward from one end (i.e., the upper end in FIG. 1A) and the other end (i.e., the lower end in FIG. 1A) of the other lateral side (i.e., the left side in FIG. 1A) of the main body 11. The device terminals 15, 16 are bent downward at their ends by bending, and further bent horizontally at their tips, thereby forming terminal portions 15a, 16a at their ends, respectively.

[0014] The base 10 is sealed within the package 9 with terminal portions 15a, 16a of the device terminals 15, 16 protruding from the side surfaces of the package 9.

[0015] The device terminals 17, together with the device terminals 15 and 16, are secondary conductors for outputting the detection result of the current to be measured output from the signal processing device 44 to an external device. In addition, the device terminals 17, together with the device terminals 15 and 16, are used to provide power or operating parameters to the signal processing device 44. In this embodiment, as an example, three device terminals 17 are arranged at equal intervals between the device terminals 15 and 16 of the base 10 with their longitudinal sides facing horizontally. The device terminals 17 are formed into a rectangular plate shape using metal, and, like the device terminals 15 and 16, their ends are bent downward by bending processing, and their tips are further bent horizontally to form terminal portions 17a at each end.

[0016] The conductor 24 is a primary conductor that forms a current path through which the current to be measured flows. In this embodiment, the conductor 24 has a generally U-shaped shape that runs from a current terminal 24a provided on one side of the right side of the package 9 (i.e., the upper side in FIG. 1A), through the inside of the package 9, back to the right side, and to a current terminal 24e provided on the other side of the right side (i.e., the lower side in FIG. 1A). The conductor 24 is formed using metal. The conductor 24 includes current terminals (also simply referred to as terminal portions) 24a and 24e, body portions 24b and 24d, and a curved portion 24c.

[0017] The terminals 24a and 24e protrude from the right side of the package 9, and are formed into terminals for inputting a current by bending the ends downward and further bending the tips horizontally.

[0018] The body portions 24b and 24d are portions that connect the terminal portions 24a and 24e to the curved portion 24c. As an example, the body portions 24b and 24d are formed in a rectangular shape, and the two terminal portions 24a and 24e are connected to the right sides at a distance from each other, and the two arms 24c1 and 24c2 of the curved portion 24c are connected to the left sides.

[0019] The curved portion 24c has two arms 24c1, 24c2 and a connecting portion 24c3 connecting the two arms 24c1, 24c2. The two arms 24c1, 24c2 may extend on the same side with respect to the connecting portion 24c3. Here, the direction in which the width of the arm 24c1 increases is also called the width direction (equivalent to the vertical direction in FIG. 1A), and the direction in which the arm 24c1 extends with respect to the connecting portion 24c3 is also called the extension direction (equivalent to the horizontal direction in FIG. 1A). That is, the width direction and the extension direction intersect. The two arms 24c1, 24c2 have a vertical width smaller than that of the body portions 24b, 24d. The curved portion 24c curves the connecting portion 24c3 in a substantially arc shape, and the two arms 24c1, 24c2 are separated from each other in the width direction from both ends and extend in the horizontal direction. The curved portion 24c may be bent in a U-shape. In the bent portion 24c, the current to be measured is input to one of the two arms 24c1, 24c2, and is output from the other arm via the connecting portion 24c3.

[0020] The conductor 24 is sealed within the package 9 with the bent portion 24c disposed between the protruding portions 12 and 14 of the base 10 and the tips of the terminal portions 24a and 24e protruding from the right side of the package 9.

[0021] The magnetic sensor 50 is a sensor that detects a magnetic field generated by a current to be measured that is passed through the conductor 24. The magnetic sensor 50 includes, as an example, two magnetoelectric conversion units, i.e., a first magnetoelectric conversion unit 50a and a second magnetoelectric conversion unit 50b, each configured to detect a vertical magnetic field (an example of a horizontal magnetic field) generated around the conductor 24. The first magnetoelectric conversion unit 50a and the second magnetoelectric conversion unit 50b are disposed on the arms 24c1 and 24c2 of the curved portion 24c of the conductor 24, respectively, and are connected in parallel. Note that the magnetic sensor 50 may include only one of the first magnetoelectric conversion unit 50a and the second magnetoelectric conversion unit 50b.

[0022] 2 shows a circuit configuration of the first magnetoelectric conversion unit 50a of the magnetic sensor 50. The first magnetoelectric conversion unit 50a includes four resistor arms Ra to Rd. Here, the four resistor arms Ra to Rd are assembled in a Wheatstone bridge circuit. That is, the resistor arms Ra and Rb are connected in series to form an output terminal Np1 therebetween, the resistor arms Rc and Rd are connected in series to form an output terminal Np2 therebetween, and the resistor arms Ra and Rb and the resistor arms Rc and Rd are connected in parallel to form a power supply terminal VDD between the resistor arms Ra and Rc and a ground terminal GND between the resistor arms Rb and Rd.

[0023] In the current sensor 100 according to this embodiment, the magnetic field detection direction (i.e., the magnetic sensing direction) from the resistive side Ra to the resistive side Rd is parallel to the width direction (the vertical direction in FIG. 1A). The magnetic field detection directions of the resistive side Ra and the resistive side Rd are equal to each other, and in this example, are vertically upward (or downward) in FIG. 1A. The magnetic field detection directions of the resistive side Rb and the resistive side Rc are equal to each other, and in this example, are vertically downward (or upward) in FIG. 1A. The magnetic field detection direction of the resistive side Ra and the resistive side Rd is opposite to the magnetic field detection direction of the resistive side Rb and the resistive side Rc.

[0024] Each of the four resistance sides Ra to Rd is formed by, for example, connecting in series a plurality of magnetoresistance elements 51 (51a to 51d). Note that, as the magnetoresistance elements, for example, tunnel type magnetoresistance elements or giant magnetoresistance elements can be adopted.

[0025] FIG. 3 shows the configuration of the magnetoresistance element 51 (51a to 51d) in a side view. The magnetoresistance element 51 is an element whose resistance value varies with the application of a magnetic field, and includes a fixed layer 51o, a tunnel layer 51p, a free layer 51q, and a cap layer 51r. The fixed layer 51o is a magnetic film whose magnetization direction is fixed. The fixed layer 51o is magnetized so that its magnetization is oriented in one axial direction within a plane (also called a magnetosensitive surface) in which the magnetic film spreads, or in a direction perpendicular to the magnetosensitive surface. The magnetization direction of the fixed layer 51o determines the magnetic field detection direction of the magnetoresistance element 51. The tunnel layer 51p is, for example, a non-magnetic insulating film having a thickness of several nanometers. The free layer 51q is a magnetic film whose magnetization direction changes with an external magnetic field. The magnetic film may be made of 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). The fixed layer 51o, the tunnel layer 51p, and the free layer 51q are stacked to form a stack. Here, electrons tunnel through the tunnel layer 51p and move from the fixed layer 51o to the free layer 51q or from the free layer 51q to the fixed layer 51o, so that a current flows in the stacking direction in the element. The cap layer 51r is a member that covers the stack from above, and may be made of an alloy containing at least one of Ta, Ru, Pt, Mn, Ir, Mg, Cu, Fe, Ni, Cr, Fe, Co, and Al, more specifically, platinum manganese (PtMn) or iridium manganese (IrMn). The magnetoresistance element 51 is covered with an insulating material (not shown), such as silicon dioxide (SiO2), silicon nitride (SiN), or the like.

[0026] When an external magnetic field is applied to the magnetoresistance element 51, the magnetization direction of the free layer 51q changes according to the direction and strength of the magnetic field due to the magnetoresistance effect (MR effect), that is, the magnetization direction of the free layer 51q changes with respect to the magnetization direction of the fixed layer 51o, thereby varying the resistance value between the fixed layer 51o and the free layer 51q. In particular, when the magnetization direction of the free layer 51q is the same as that of the fixed layer 51o (the magnetizations of the two layers are parallel), the resistance value is small, and when they are opposite (the magnetizations of the two layers are antiparallel), the resistance value is large.

[0027] In addition, by connecting multiple magnetoresistance elements 51 in series, the DC voltage resistance can be improved. Here, by connecting the electrode piece 52 to the cap layer 51r via the electrode bar 51s and connecting the electrode piece 53 to the lower surface of the fixed layer 51o, the magnetoresistance element 51 can be connected to another magnetoresistance element 51 via these electrodes 52, 53. That is, multiple magnetoresistance elements 51 can be arranged in a plane. Also, by connecting the cap layer 51r of the magnetoresistance element 51 to the fixed layer 51o of the other magnetoresistance element 51 via the electrode bar 51s, multiple magnetoresistance elements 51 can be arranged in a three-dimensional manner.

[0028] At least a part of the first magnetoelectric conversion unit 50a (for example, any one of a plurality of unit areas Ea1 to Ea4, Eb1 to Eb4, Ec1 to Ec4, and Ed1 to Ed4 included in the resistor sides Ra to Rd described later) is arranged on the arm 24c1. When a current to be measured flows through the conductor 24 and a magnetic field is generated around the conductor 24, a vertical magnetic field is applied to the resistor sides Ra to Rd (the magnetoresistance elements 51a to 51d included in the resistor sides) of the first magnetoelectric conversion unit 50a arranged on the arm 24c1 of the conductor 24, and the respective resistance values ​​fluctuate. For example, the resistance values ​​of the resistor sides Ra and Rd increase (or decrease), and the resistance values ​​of the resistor sides Rb and Rc decrease (or increase), thereby destroying the resistance balance of the resistor sides Ra to Rd. Here, the magnetic field strength can be detected by inputting a drive voltage to the power supply terminal VDD with respect to the ground terminal GND and detecting a differential voltage output from between the output terminals Np1 and Np2.

[0029] The second magnetoelectric converter 50b is configured similarly to the first magnetoelectric converter 50a. The first magnetoelectric converter 50a includes four resistor arms Re to Rh (see FIG. 4C). Here, the four resistor arms Re to Rh are arranged in a Wheatstone bridge circuit. That is, the resistor arms Re and Rf are connected in series to form an output terminal Np1 therebetween, the resistor arms Rg and Rh are connected in series to form an output terminal Np2 therebetween, and the resistor arms Re and Rf and the resistor arms Rg and Rh are connected in parallel to form a power supply terminal VDD between the resistor arms Re and Rg and a ground terminal GND between the resistor arms Rf and Rh.

[0030] The magnetic field detection direction (i.e., magnetic sensing direction) from resistor side Re to resistor side Rh is parallel to the width direction (vertical direction in FIG. 1A). The magnetic field detection directions of resistor side Re and resistor side Rh are equal to each other, and in this example, are vertically upward (or downward) in FIG. 1A. The magnetic field detection direction of resistor side Rf and resistor side Rg is equal to each other, and in this example, are vertically downward (or upward) in FIG. 1A. The magnetic field detection direction of resistor side Re and resistor side Rh is opposite to the magnetic field detection direction of resistor side Rf and resistor side Rg.

[0031] Each of the four resistance sides Re to Rh is formed by, for example, connecting in series a plurality of magnetoresistance elements 51 (51e to 51h). Note that, as the magnetoresistance elements, for example, tunnel type magnetoresistance elements or giant magnetoresistance elements can be adopted.

[0032] At least a part of the second magnetoelectric converter 50b (for example, any one of a plurality of unit areas Ea1 to Ea4, Eb1 to Eb4, Ec1 to Ec4, and Ed1 to Ed4 included in the resistor sides Re to Rh described later) is arranged on the arm 24c2. When a current to be measured flows through the conductor 24 and a magnetic field is generated around the conductor 24, a vertical magnetic field is applied to the resistor sides Re to Rh (the magnetoresistance elements 51e to 51h included in the resistor sides) of the second magnetoelectric converter 50b arranged on the arm 24c2 of the conductor 24, and the respective resistance values ​​fluctuate. For example, the resistance values ​​of the resistor sides Re and Rh increase (or decrease), and the resistance values ​​of the resistor sides Rf and Rg decrease (or increase), thereby destroying the resistance balance of the resistor sides Re to Rh. Here, the magnetic field strength can be detected by inputting a drive voltage to the power supply terminal VDD with respect to the ground terminal GND and detecting a differential voltage output from between the output terminals Np1 and Np2.

[0033] In the magnetic sensor 50, the second magnetic-electric converter 50b may be connected in parallel to the first magnetic-electric converter 50a. That is, the ground terminals GND of the first magnetic-electric converter 50a and the second magnetic-electric converter 50b may be connected to each other, and the power supply terminals VDD of the first magnetic-electric converter 50a and the second magnetic-electric converter 50b may be connected to each other. The configurations of the first magnetic-electric converter 50a and the second magnetic-electric converter 50b of the magnetic sensor 50 will be described later.

[0034] The first magnetoelectric conversion unit 50a and the second magnetoelectric conversion unit 50b of the magnetic sensor 50 are connected to the signal processing device 44 by wire bonding, and output a voltage according to the detected magnetic field strength to the signal processing device 44 as an output signal.

[0035] The signal processing device 44 is a device that processes the output signal of the magnetic sensor 50 to calculate the amount of the current to be measured flowing through the conductor 24. The signal processing device 44 may incorporate a memory, a sensitivity correction circuit, an offset correction circuit that corrects the offset of the output, an amplifier circuit that amplifies the output signal from the magnetic sensor 50, and a temperature correction circuit that corrects the output according to temperature. The signal processing device 44 is supported on the main body 11 of the base 10, and is connected to the device terminals 15, 16 and three device terminals 17 of the base 10 by wire bonding. Thus, the signal processing device 44 outputs the calculation result of the amount of the current to be measured flowing through the conductor 24 via the device terminals 15, 16, and 17.

[0036] FIG. 4A shows an example of the arrangement of the magnetic sensor 50 (the first magnetic-electric conversion unit 50a and the second magnetic-electric conversion unit 50b). As described above, the first magnetic-electric conversion unit 50a and the second magnetic-electric conversion unit 50b can be arranged on the two arms 24c1 and 24c2 of the conductor 24, respectively. By calculating the difference between the output signals of the first magnetic-electric conversion unit 50a and the second magnetic-electric conversion unit 50b, the offset caused by the disturbance magnetic field can be canceled. The magnetic sensor 50 arranged at such a position is configured to detect a horizontal magnetic field parallel to the upper surface of the conductor 24 (in this example, a magnetic field in the vertical direction in FIG. 1A). Note that one of the first magnetic-electric conversion unit 50a and the second magnetic-electric conversion unit 50b may be arranged on the conductor 24 (the two arms 24c1 and 24c2 or the connecting portion 24c3, etc.).

[0037] FIG. 4B shows the magnetic field detection directions of the four resistive sides Ra to Rd (the magnetoresistance elements 51a to 51d included in each) of the first magnetoelectric conversion unit 50a in FIG. 4A. The resistive side Ra (the magnetoresistance element 51a) and the resistive side Rd (the magnetoresistance element 51d) have the same magnetic field detection direction, which is one direction in a uniaxial direction parallel to the upper surface of the conductor 24 in this example (represented by a hollow arrow in the figure). The resistive side Rb (the magnetoresistance element 51b) and the resistive side Rc (the magnetoresistance element 51c) have the same magnetic field detection direction, which is the other direction in a uniaxial direction parallel to the upper surface of the conductor 24 in this example (represented by a filled arrow in the figure). The magnetic field detection directions of the resistive sides Ra and Rd are opposite to the magnetic field detection directions of the resistive sides Rb and Rc. This allows the first magnetoelectric conversion unit 50a to detect the horizontal magnetic field generated on the upper surface of the arm 24c1 of the conductor 24.

[0038] FIG. 4C shows the magnetic field detection directions of the four resistive sides Re to Rh (the magnetoresistance elements 51e to 51h included in each) of the second magnetoelectric conversion unit 50b in FIG. 4A. The resistive side Re (the magnetoresistance element 51e) and the resistive side Rh (the magnetoresistance element 51h) have the same magnetic field detection direction, which is one direction in a uniaxial direction parallel to the upper surface of the conductor 24 in this example (represented by a hollow arrow in the figure). The resistive side Rf (the magnetoresistance element 51f) and the resistive side Rg (the magnetoresistance element 51g) have the same magnetic field detection direction, which is the other direction in a uniaxial direction parallel to the upper surface of the conductor 24 in this example (represented by a filled arrow in the figure). The magnetic field detection direction of the resistive side Re and the resistive side Rh is opposite to the magnetic field detection direction of the resistive side Rf and the resistive side Rg. This allows the second magnetoelectric conversion unit 50b to detect the horizontal magnetic field generated on the upper surface of the arm 24c2 of the conductor 24.

[0039] FIG. 5A shows another example of the arrangement of the magnetic sensor 50 (first magnetoelectric conversion unit 50a and second magnetoelectric conversion unit 50b). The first magnetoelectric conversion unit 50a is arranged in a gap region surrounded by the curved portion 24c of the conductor 24. Furthermore, the second magnetoelectric conversion unit 50b may be arranged in the vicinity of one of the two arms 24c1, 24c2 of the conductor 24 (on the right side of the arm 24c1 in this example). This makes it possible to cancel the disturbance magnetic field. The first magnetoelectric conversion unit 50a and the second magnetoelectric conversion unit 50b arranged in such a position are configured to detect a vertical magnetic field perpendicular to the upper surface of the conductor 24 (in this example, a magnetic field in the height direction in FIG. 1A).

[0040] The first magneto-electric converter 50a and the second magneto-electric converter 50b can be disposed in the vicinity of the conductor 24 by attaching them to the lower surfaces of the protruding parts 12, 14 of the base 10, with an insulating member 18 (see FIG. 5A) laid between the protruding parts 12, 14, and supporting them on the insulating member 18. The insulating member 18 is formed into a film shape using a material with high dielectric strength, such as polyimide tape, for example.

[0041] Also, the curved portion 24c of the conductor 24 may be raised relative to the body portions 24b, 24d by providing a step in the height direction by step processing (e.g., half-punching, etching, forming, coining, etc.). As a result, the bottom surface of the curved portion 24c becomes higher than the upper surface of the insulating member 18 attached to the bottom surfaces of the protruding portions 12, 14 of the base 10, and the primary conductor including the conductor 24 is separated from the insulating member 18 connected to the secondary conductor including the device terminals 15, 16, 17, thereby obtaining a high dielectric strength voltage between the primary conductor and the secondary conductor in the package 9.

[0042] FIG. 5B shows the magnetic field detection directions of the four resistive sides Ra to Rd (the magnetoresistance elements 51a to 51d included in each) of the first magnetoelectric conversion unit 50a in FIG. 5A. The resistive side Ra (the magnetoresistance element 51a) and the resistive side Rd (the magnetoresistance element 51d) have the same magnetic field detection direction, which is perpendicular to the upper surface of the conductor 24 in this example (represented by a hollow arrow in the figure). The resistive side Rb (the magnetoresistance element 51b) and the resistive side Rc (the magnetoresistance element 51c) have the same magnetic field detection direction, which is perpendicular to the upper surface of the conductor 24 in this example (represented by a filled arrow in the figure). The magnetic field detection directions of the resistive sides Ra and Rd are opposite to those of the resistive sides Rb and Rc. This allows the first magnetoelectric conversion unit 50a to detect a vertical magnetic field generated in the gap region of the conductor 24.

[0043] FIG. 5C shows the magnetic field detection directions of the four resistive sides Re to Rh (the magnetoresistance elements 51e to 51h included in each) of the second magnetoelectric conversion unit 50b in FIG. 5A. The resistive side Re (the magnetoresistance element 51e) and the resistive side Rh (the magnetoresistance element 51h) have the same magnetic field detection direction, which is perpendicular to the upper surface of the conductor 24 in this example (represented by a hollow arrow in the figure). The resistive side Rf (the magnetoresistance element 51f) and the resistive side Rg (the magnetoresistance element 51g) have the same magnetic field detection direction, which is perpendicular to the upper surface of the conductor 24 in this example (represented by a filled arrow in the figure). The magnetic field detection direction of the resistive side Re and the resistive side Rh is opposite to the magnetic field detection direction of the resistive side Rf and the resistive side Rg. This allows the second magnetoelectric conversion unit 50b to detect the vertical magnetic field generated around the conductor 24.

[0044] 6A shows the principle of di / dt noise generation associated with induced electromotive force. When a magnetic field (magnetic flux density B) is applied to two wires constituting a Wheatstone bridge circuit (i.e., closed loop) of the magnetic sensor 50 (first magnetoelectric conversion unit 50a and second magnetoelectric conversion unit 50b) and a magnetic flux (φ=BS, S is the area between the wires) passes between the two wires, an induced electromotive force (V=-dφ / dt=-SdB / dt) is generated in the two wires so as to cancel the increase and decrease in the magnetic flux density (magnetic field strength B / μ, μ is magnetic permeability). In the case of parallel wiring, the leftward induced electromotive force (represented by a hollow arrow in the figure) applied to the upper wire and the rightward induced electromotive force (represented by a filled arrow in the figure) applied to the lower wire due to each of the magnetic fluxes passing between the wires are added together, and a large induced electromotive force is generated between the two wires. As a result, noise associated with the induced electromotive force, so-called di / dt noise, is superimposed on the output signal of the magnetic sensor.

[0045] Figure 6B shows the principle of suppressing di / dt noise. By twisting two wires that make up a closed loop to form a twisted wire, multiple partial loops of equal area are formed within the closed loop. When a magnetic field (magnetic flux density B) is applied to the two wires and magnetic flux passes through each of the multiple partial loops, induced electromotive forces are generated in the wires that make up each partial loop to offset the increase and decrease in magnetic flux density. In the case of twisted wire, in each partial loop, a leftward induced electromotive force (represented by a white arrow in the figure) is applied to the upper wire, and a rightward induced electromotive force (represented by a black arrow in the figure) is applied to the lower wire. However, in each of the two wires, the direction of the induced electromotive force changes for each part that makes up the partial loop, so that the induced electromotive force applied to the entire wiring is suppressed. The direction of the induced electromotive force generated in each loop is also called the polarity. In particular, when an even number of partial loops are formed, the induced electromotive force applied to the entire wiring is offset. In this way, by providing an even number of partial loops with equal loop areas and opposite polarities in the Wheatstone bridge circuit of the magnetic sensor 50, it is possible to cancel or strongly suppress di / dt noise.

[0046] 7A and 7B show the arrangement of the multiple magnetoresistance elements 51 in the first magneto-electric converting unit 50a and the second magneto-electric converting unit 50b, i.e., the planar arrangement and the three-dimensional arrangement, respectively. Each of the resistive sides Ra to Rh includes one or more unit areas E in which at least some of the multiple magnetoresistance elements 51 forming each of the resistive sides are adjacent (closely adjacent) and arranged inside the multiple magnetoresistance elements 51. In other words, the multiple magnetoresistance elements 51 forming one resistive side (e.g., the resistive side Ra) are divided into one or more groups and arranged in each unit area E. The unit area E may be a planar area or a three-dimensional area.

[0047] 7A, 15 magnetoresistance elements 51 are arranged in a 3×5 matrix in a rectangular planar area E. Here, the magnetoresistance element 51 located in the i-th column (i-th from the top) and j-th row (j-th from the left) is referred to as the (i,j) magnetoresistance element 51. The top surfaces of the (1,1) and (1,2) magnetoresistance elements 51, the (1,3) and (1,4) magnetoresistance elements 51, the (1,5) and (2,5) magnetoresistance elements 51, the (2,4) and (2,3) magnetoresistance elements 51, the (2,2) and (2,1) magnetoresistance elements 51, the (3,1) and (3,2) magnetoresistance elements 51, and the (3,3) and (3,4) magnetoresistance elements 51 are connected by electrode pieces 52. The bottom surfaces of the magnetoresistance elements 51 of (1,2) and (1,3), the magnetoresistance elements 51 of (1,4) and (1,5), the magnetoresistance elements 51 of (2,5) and (2,4), the magnetoresistance elements 51 of (2,3) and (2,2), the magnetoresistance elements 51 of (2,1) and (3,1), the magnetoresistance elements 51 of (3,2) and (3,3), and the magnetoresistance elements 51 of (3,4) and (3,5) are connected by an electrode piece 53. As a result, the 15 magnetoresistance elements 51 are arranged adjacent to each other in the unit area E by being connected in series so as to make one and a half round trips in the horizontal direction. The outermost periphery of the 15 magnetoresistance elements 51 at this time (shown by the dashed line in the figure) is also the unit area E.

[0048] In the side view shown in Fig. 7B, 15 magnetoresistance elements 51 constituting one column shown in Fig. 7A are arranged in a 3 x 5 matrix in a rectangular three-dimensional area E. That is, by arranging three magnetoresistance elements 51 connected in series in the height direction via electrode rods 51s in a plane as shown in Fig. 7A, 45 magnetoresistance elements 51 connected in series are three-dimensionally arranged in a 3 x 5 x 3 three-dimensional matrix in a cubic unit area E. The outermost periphery of the 45 magnetoresistance elements 51 (indicated by a dashed line in the figure) at this time is also the unit area E.

[0049] Fig. 8A shows the arrangement of unit areas Ea1-Ea4, Eb1-Eb4, Ec1-Ec4, and Ed1-Ed4 in the first magneto-electric converter 50a. The vertical direction in Fig. 8A corresponds to the vertical direction in Fig. 4A, and the horizontal direction in Fig. 8A corresponds to the horizontal direction in Fig. 4A. Each of the four resistance sides Ra-Rd includes a plurality of unit areas E (four, for example), and the plurality of magnetoresistance elements 51 forming each resistance side are divided into four groups and arranged in the respective plurality of unit areas E. The unit areas Ea1-Ea4 included in each resistance side (for example, resistance side Ra) are wired and all of the magnetoresistance elements 51 included in the unit areas Ea1-Ea4 are connected in series.

[0050] The unit areas Ea1-Ea4, Eb1-Eb4, Ec1-Ec4, and Ed1-Ed4 of the resistor side Ra to resistor side Rd are arranged in the width direction of the arm 24c1 (left-right direction in FIG. 8A). Here, each of the resistor sides Ra to Rd includes unit areas Ea1-Ed1 and unit areas Ea2-Ed2 arranged on one side and the other side (upper side and lower side in FIG. 8A) of the conduction direction of the current flowing through the conductor 24 (arm 24c1). The unit areas Ea1-Ed1 are arranged from left to right in the order of Eb1, Ec1, Ed1, and Ea1. The unit areas Ea2-Ed2 are arranged from left to right in the reverse order of the unit areas Ea1-Ed1, that is, in the order of Ea2, Ed2, Ec2, and Eb2. As a result, the unit areas Ea1-Ed1 and Ea2-Ed2 included in each of the resistance sides Ra to Rd are arranged with 180-degree rotational symmetry on the arm 24c1. In this way, by twisting the connection wires of the magnetoresistance elements 51 constituting the resistance sides Ra-Rd with the unit areas Ea1-Ed1 and unit areas Ea2-Ed2 of the resistance sides Ra-Rd in reverse order, the partial loop formed by the connection wires of the magnetoresistance elements 51 can be made smaller.

[0051] In addition, the unit areas Ea1 to Ed1 and unit areas Ea2 to Ed2 of each of the resistor sides Ra, Rb, Rc, and Rd may be arranged in any order as long as the unit areas Ea1 to Ed1 and unit areas Ea2 to Ed2 are arranged in the reverse order to each other.

[0052] Furthermore, each of the resistor sides Ra to Rd includes unit areas Ea3-Ed3 and unit areas Ea4-Ed4 arranged on one side and the other side (upper side and lower side in FIG. 8A) of the conduction direction of the current flowing through the conductor 24 (arm 24c1). The unit areas Ea3-Ed3 and unit areas Ea4-Ed4 are arranged below the unit areas Ea1-Ed1 and unit areas Ea2-Ed2, but are not limited to this and may be arranged at any position such as the upper side, left side, right side, diagonal, etc. The unit areas Ea3-Ed3 are arranged from left to right in the order of Eb3, Ec3, Ed3, Ea3. The unit areas Ea4-Ed4 are arranged from left to right in the reverse order of the unit areas Ea3-Ed3, that is, in the order of Ea4, Ed4, Ec4, Eb4. As a result, the unit areas Ea3-Ed3 and Ea4-Ed4 included in each of the resistance sides Ra to Rd are arranged 180-degree rotationally symmetrically on the arm 24c1. In this way, by twisting the connection wires of the magnetoresistance elements 51 constituting the resistance sides Ra-Rd with the unit areas Ea3-Ed3 and unit areas Ea4-Ed4 of the resistance sides Ra-Rd arranged in reverse order, it is possible to reduce the partial loop formed by the connection wires of the magnetoresistance elements 51. Note that the arrangement of the unit areas Ea3-Ed3 and unit areas Ea4-Ed4 does not need to be unified with the arrangement of the unit areas Ea1-Ed1 and unit areas Ea2-Ed2 as long as they are arranged in the reverse order.

[0053] In addition, the unit areas Ea3 to Ed3 and the unit areas Ea4 to Ed4 of the resistor side Ra, resistor side Rb, resistor side Rc, and resistor side Rd may be arranged in any order as long as the unit areas Ea3 to Ed3 and the unit areas Ea4 to Ed4 are arranged in the reverse order to each other.

[0054] In this way, by providing an even number of partial loops with equal loop areas and opposite polarities in the connection line of the magnetoresistive element 51 included in the resistor side Ra to the resistor side Rd, di / dt noise can be canceled or strongly suppressed.

[0055] Fig. 8B shows the arrangement of unit areas Ee1-Ee4, Ef1-Ef4, Eg1-Eg4, and Eh1-Eh4 in the second magneto-electric converter 50b. The up-down direction in Fig. 8B corresponds to the up-down direction in Fig. 4A, and the left-right direction in Fig. 8B corresponds to the left-right direction in Fig. 4A. Each of the four resistance sides Re-Rh includes a plurality of unit areas E (four, for example), and the plurality of magnetoresistance elements 51 forming each resistance side are divided into four groups and arranged in each unit area E. The unit areas Re1-Re4 included in each resistance side (for example, resistance side Re) are wired and all of the magnetoresistance elements 51 included in the unit areas Re1-Re4 are connected in series.

[0056] The unit areas Ee1-Ee4, Ef1-Ef4, Eg1-Eg4, and Eh1-Eh4 of the resistor side Re to resistor side Rh are arranged in the width direction of the arm 24c2 (left-right direction in FIG. 8B). Here, each of the resistor sides Re to Rh includes unit areas Ee1-Eh1 and unit areas Ee2-Eh2 arranged on one side and the other side (upper side and lower side in FIG. 8B) of the conduction direction of the current flowing through the conductor 24 (arm 24c2). The unit areas Ee1-Eh1 are arranged from left to right in the order of Ef1, Eg1, Eh1, and Ee1. The unit areas Ee2-Eh2 are arranged from left to right in the reverse order of the unit areas Ee1-Eh1, that is, in the order of Ee2, Eh2, Eg2, and Ef2. As a result, the unit areas Ee1-Eh1 and Ee2-Eh2 included in each of the resistance sides Re to Rh are arranged with 180-degree rotational symmetry on the arm 24c2. In this way, by twisting the connection wires of the magnetoresistance elements 51 constituting the resistance sides Re-Rh with the arrangement of the unit areas Ee1-Eh1 and unit areas Ee2-Eh2 of the resistance sides Re-Rh in reverse order, the partial loop formed by the connection wires of the magnetoresistance elements 51 can be made smaller.

[0057] In addition, the unit areas Ee1-Eh1 and unit areas Ee2-Eh2 of the resistance side Re, resistance side Rf, resistance side Rg, and resistance side Rh may be arranged in any order as long as the unit areas Ee1-Eh1 and unit areas Ee2-Eh2 are arranged in the reverse order to each other.

[0058] Furthermore, each of the resistor sides Re to Rh includes unit areas Ee3-Eh3 ​​and unit areas Ee4-Eh4, which are respectively arranged on one side and the other side (upper side and lower side in FIG. 8B) of the conduction direction of the current flowing through the conductor 24 (arm 24c2). Note that the unit areas Ee3-Eh3 ​​and unit areas Ee4-Eh4 are arranged below the unit areas Ee3-Eh3 ​​and unit areas Ee4-Eh4, but are not limited to this and may be arranged at any position such as the upper side, left side, right side, diagonal, etc. The unit areas Ee3-Eh3 ​​are arranged from left to right in the order of Ef3, Eg3, Eh3, Ee3. The unit areas Ee4-Eh4 are arranged from left to right in the reverse order of the unit areas Ee3-Eh3, that is, in the order of Ee4, Eh4, Eg4, Ef4. As a result, the unit areas Ee3-Eh3 ​​and Ee4-Eh4 included in each of the resistance sides Re to Rh are arranged 180-degree rotationally symmetrically on the arm 24c2. In this way, by twisting the connection wires of the magnetoresistance elements 51 constituting the resistance sides Re-Rh with the unit areas Ee3-Eh3 ​​and unit areas Ee4-Eh4 of the resistance sides Re-Rh arranged in reverse order, it is possible to reduce the partial loop formed by the connection wires of the magnetoresistance elements 51. Note that the arrangement of the unit areas Ee3-Eh3 ​​and unit areas Ee4-Eh4 does not need to be unified with the arrangement of the unit areas Ee1-Eh1 and unit areas Ee2-Eh2 as long as they are arranged in the reverse order.

[0059] In addition, the unit areas Ee3 to Eh3 and the unit areas Ee4 to Eh4 of the resistance side Re, the resistance side Rf, the resistance side Rg, and the resistance side Rh may be arranged in any order as long as the unit areas Ee3 to Eh3 and the unit areas Ee4 to Eh4 are arranged in the reverse order to each other.

[0060] In this way, by providing an even number of partial loops with equal loop areas and opposite polarities in the connection line of the magnetoresistance element 51 included in the resistance side Re to the resistance side Rh, it is possible to cancel or strongly suppress the di / dt noise. On the other hand, a difference in magnetic sensitivity occurs between the partial loops due to the strength distribution of the magnetic field, and a common-mode voltage may be generated.

[0061] 9 shows the magnetic field strength with respect to position X on arm 24c1 of conductor 24 and the common-mode voltage Vcm output from first magnetoelectric converting unit 50a. Position X on arm 24c1 is defined based on gap center line L of conductor 24 (see FIG. 4A). The common-mode voltage Vcm of first magnetoelectric converting unit 50a is defined as the average of voltages output from output terminals Np1, Np2 when the center of first magnetoelectric converting unit 50a (the center of the 4×4 unit area in FIG. 8A) is located at distance X from gap center line L. The width W of arm 24c1 is, for example, 620 μm, and position X on arm 24c1 is indicated by hatching. The width w of the first magnetic-electric converter 50a can be defined as the distance between the center of gravity (which may be the center of a plane) of the unit area of ​​the resistance sides Ra-Rd located on the outermost side in the width direction of the arm 24c1 (for example, the unit area Eb1 located on the leftmost side in the first row of Figure 8A) and the center of gravity (which may be the center of a plane) of the unit area of ​​the resistance sides Ra-Rd located on the other outermost side (the unit area Ea1 located on the rightmost side in the first row of Figure 8A).

[0062] 8A, the magnetoresistance elements are aligned in a 4×4 rectangular array, and so the center of the first magnetoelectric converter 50a is defined as the center of the rectangle. On the other hand, the magnetoresistance elements do not necessarily need to be aligned in a rectangular array, and in this case, the center of the first magnetoelectric converter 50a may be defined as the center of the rectangle that surrounds all of the centers of gravity of the magnetoresistance elements constituting the first resistance side to the fourth resistance side in a plan view, and has two sides parallel to the width direction and two sides perpendicular to the width direction, and has the smallest area.

[0063] When a unit current is passed through the conductor 24, a magnetic field Bx parallel to the width direction is generated on the upper surface of the arm 24c1. The parallel magnetic field Bx is weakest in the width direction (equal to the X-axis direction) at the gap center line L, increases as it moves away from the gap center line L in the +X direction, is strongest at a position slightly away from the center line of the arm 24c1 from the origin, and exhibits an intensity profile that attenuates as it moves further away from the gap center line L in the +X direction. In contrast, when the width w of the first magnetoelectric converter 50a is 150 μm, the in-phase voltage Vcm output from the first magnetoelectric converter 50a exhibits a positive value when the center of the first magnetoelectric converter 50a is located within the gap, becomes zero at the extreme inside of the arm 24c1 (near 150 μm from the gap center line L), increases in the negative direction as it moves away from the gap center line L in the +X direction, becomes extremely small slightly closer to the gap center line L than the maximum position of the parallel magnetic field Bx, and exhibits a profile in which it increases in the positive direction as it moves further away from the gap center line L in the +X direction. When the width w of the first magnetoelectric converter 50a is 100 μm, the in-phase voltage Vcm output from the first magnetoelectric converter 50a has an extremely small absolute value for the width w=150 μm and exhibits a profile similar to that when the width w=150 μm.

[0064] Therefore, the center of the first magnetoelectric converter 50a (from the resistor side Ra to the resistor side Rd) is preferably located on the gap center line L (i.e., the arm 24c2) side in the width direction from the maximum position of the parallel magnetic field Bx generated on the arm 24c1 when a current is conducted through the conductor 24. This reduces the parallel magnetic field Bx and suppresses the common-mode voltage Vcm. Also, the center of the first magnetoelectric converter 50a (from the resistor side Ra to the resistor side Rd) is preferably located on the arm 24c2 side from the center line of the arm 24c1 in the width direction. This allows the magnetic sensor 50, including the first magnetoelectric converter 50a and the second magnetoelectric converter 50b, to be configured compactly.

[0065] FIG. 10 shows the common-mode voltage Vcm output from the first magnetoelectric converter 50a with respect to the ratio of the width w of the first magnetoelectric converter 50a to the width W of the arm 24c1. The center of the first magnetoelectric converter 50a can be located at any position on the upper surface of the arm 24c1, and can be located on the center line of the arm 24c1 where the common-mode voltage Vcm can be maximized. The common-mode voltage Vcm of the first magnetoelectric converter 50a is the average of the voltages output from the output terminals Np1 and Np2 when a unit current is passed through the conductor 24. The common-mode voltage Vcm increases as the ratio w / W increases, and exceeds the standard limit of 0.01 mV / A when the ratio is about 0.3 or more. Therefore, it is desirable that the width w of the first magnetoelectric converter 50a is smaller than the width W of the arm 24c1, and the common-mode voltage Vcm can be suppressed to below the standard limit when the width w is 0.3 times or less than the width W of the arm 24c1. The width w of the first magneto-electric converting part 50a may be 0.27 times or less, preferably 0.25 times or less, more preferably 0.23 times or less, and even more preferably 0.20 times or less, the width W of the arm 24c1.

[0066] A method for manufacturing the current sensor 100 will now be described.

[0067] 11A, first, a single metal plate is pressed to form a pattern of the base 10, the multiple device terminals 17, and the conductors 24. This pattern includes the base 10, the multiple device terminals 17, and the conductors 24, with their terminal portions connected to the inside of a rectangular frame (not shown).

[0068] Next, the pattern is subjected to step processing to provide steps at the device terminals 15 and 16 of the base 10, the multiple device terminals 17, and the conductor 24. This raises the inner portion of the pattern relative to the frame and those terminal portions connected to the frame.

[0069] 11B, next, the magnetic sensor 50 (first magneto-electric converter 50a and second magneto-electric converter 50b) and the signal processing device 44 are installed. Here, the first magneto-electric converter 50a and the second magneto-electric converter 50b are respectively disposed on the arms 24c1 and 24c2 of the conductor 24. The signal processing device 44 is disposed on the main body 11 of the base 10.

[0070] As shown in FIG. 11C, next, the magnetic sensor 50 (the first magneto-electric converting unit 50a and the second magneto-electric converting unit 50b) and the signal processing device 44 are connected by wire bonding, and the signal processing device 44 and the device terminals 15, 16, and 17 are connected.

[0071] 11D, the pattern is then molded, leaving only the frame and the base 10 connected thereto, the multiple device terminals 17, and the terminal portion of the conductor 24. As a result, the package 9 is molded, and the magnetic sensor 50, the signal processing device 44, and the inner portion of the pattern in which they are installed are sealed therein.

[0072] Finally, the frame exposed from the package 9 is cut from the pattern. As a result, the base 10, the multiple device terminals 17, and the conductor 24 are separated from one another, and the current sensor 100 is completed.

[0073] 12A and 12B show the internal structure of a current sensor 110 according to a modified example, seen through the package 9, in top and side views, respectively. Here, FIG. 12B shows a cross-sectional structure of the current sensor 110 with respect to the reference line BB in FIG. 12A. The up-down direction in FIG. 12A is the vertical direction, the left-right direction in FIG. 12A and FIG. 12B is the horizontal direction, and the up-down direction in FIG. 12B is the height direction. The current sensor 110 is a sensor that measures the amount of current by detecting a magnetic field generated around a conductor 24 when a current to be measured flows through the conductor 24 using a magnetic sensor 60, and can particularly suppress di / dt noise due to induced electromotive force and / or differential amplification noise associated with the spread of the magnetic field distribution. The current sensor 110 includes a package 9, a plurality of device terminals 17, a conductor 24, and a magnetic sensor 60.

[0074] The package 9 is a member that seals and protects each component of the current sensor 110, except for the multiple device terminals 17 and the respective terminal portions of the conductors 24. The package 9 can be formed using the same material as the package 9 in the current sensor 100 according to the first embodiment.

[0075] The multiple device terminals 17 are secondary conductors for outputting the detection result of the current to be measured output from the magnetic sensor 60 to an external device. In this example, for example, eight device terminals 17 are arranged at equal intervals on the left side of the package 9 with their longitudinal directions facing horizontally. The multiple device terminals 17 are formed in the same manner as those in the current sensor 100 according to the first embodiment.

[0076] The conductor 24 is a primary conductor that forms a current path through which the current to be measured flows. The conductor 24 is formed in the same manner as that in the current sensor 100 according to the first embodiment, with the terminals 24a and 24e being disposed on the right side of the package 9 and the two arms 24c1 and 24c2 included in the bent portion 24c being disposed in the center of the package 9.

[0077] The magnetic sensor 60 is a sensor that detects a magnetic field generated by a measured current flowing through the conductor 24. The magnetic sensor 60 is configured to detect a vertical magnetic field (an example of a horizontal magnetic field) generated around the conductor 24, for example, and includes a substrate 61, two magnetoelectric conversion units 62, and a signal processing device 63.

[0078] The substrate 61 is a plate-like member that supports the two magnetoelectric conversion parts 62. The substrate 61 is formed using, for example, silicon (Si), and has a plurality of wirings (not shown) provided on its upper surface.

[0079] The two magnetoelectric conversion units 62 detect a magnetic field generated by a current to be measured that is passed through the conductor 24. The two magnetoelectric conversion units 62 include four resistance arms connected in a Wheatstone bridge circuit shape using magnetoresistance elements 51 arranged on a substrate 61, similar to the first magnetoelectric conversion unit 50a and the second magnetoelectric conversion unit 50b described above. The two magnetoelectric conversion units 62 are arranged on the substrate 61 spaced apart in the vertical direction (width direction of the arms 24c1, 24c2), and the power supply terminal VDD, ground terminal GND, and output terminals Np1, Np2 of each are connected to a signal processing device 63 via wiring on the substrate 61.

[0080] The signal processing device 63 is a device that processes the output signals of the two magnetoelectric conversion units 62 to calculate the amount of the current to be measured flowing through the conductor 24. The signal processing device 63 can be configured in the same manner as the above-mentioned signal processing device 44. The signal processing device 63 is monolithically formed on the substrate 61 together with the two magnetoelectric conversion units 62, and in this example, is disposed at the center of the substrate 61, and is connected to the device terminal 17 via wiring (not shown) laid on the substrate 61 and wire bonding. This allows the signal processing device 63 to output the calculation result of the amount of the current to be measured flowing through the conductor 24 via the device terminal 17.

[0081] The magnetic sensor 60 is disposed on the curved portion 24c of the conductor 24. As a result, the two magnetoelectric converting units 62 are disposed on the two arms 24c1, 24c2 of the curved portion 24c, respectively. As a result, a driving voltage can be applied to the two magnetoelectric converting units 62 via the device terminal 17, and the amount of the current to be measured calculated by the signal processing device 63 based on the respective output voltages can be output.

[0082] A method for manufacturing the current sensor 110 according to the modified example will be described.

[0083] 13A, first, a single metal plate is pressed to form a pattern of multiple device terminals 17 and conductors 24. This pattern includes multiple device terminals 17 and conductors 24 with their terminal portions connected inside a rectangular frame (not shown).

[0084] Next, the pattern is subjected to step processing to provide steps in the device terminals 17 and the conductors 24. As a result, terminal portions 17a are formed in the device terminals 17 and terminal portions 24a, 24e are formed in the conductors 24, and the inner portions of the pattern are raised relative to these terminal portions.

[0085] 13B, next, the magnetic sensor 60 is placed on the curved portion 24c of the conductor 24. Here, the two magnetoelectric converting units 62 are disposed on the arms 24c1 and 24c2 of the conductor 24, respectively.

[0086] As shown in FIG. 13C, next, the magnetic sensor 60 is connected to the multiple device terminals 17 by wire bonding.

[0087] 13D, the pattern is then molded to form the package 9, leaving only the frame and the terminal portion 17a of the multiple device terminals 17 and the terminal portions 24a, 24e of the conductors 24 connected thereto. Thus, the package 9 is molded, and the magnetic sensor 60 and the inner portion of the pattern are sealed therein.

[0088] Finally, the frame exposed from the package 9 is cut from the pattern. As a result, the multiple device terminals 17 and the conductors 24 are separated from each other, and the current sensor 110 is completed.

[0089] The magnetic sensor 60 may not include the signal processing device 63, and wiring on the substrate 61 connected to the power supply terminal VDD, the ground terminal GND, and the output terminals Np1 and Np2 of the two magnetoelectric conversion units 62 may be connected to the device terminal 17 by wire bonding. This allows a drive voltage to be applied to the two magnetoelectric conversion units 62 via the device terminal 17, and each output voltage to be output.

[0090] The magnetic sensor 50 according to this embodiment is a first magneto-electric conversion unit 50a including a resistor side Ra, a resistor side Rb, a resistor side Rc, and a resistor side Rd each formed by connecting a plurality of magnetoresistance elements 51 in series, the magnetic sensing directions of the resistor side Ra and the resistor side Rd are equal to each other, the magnetic sensing directions of the resistor side Rb and the resistor side Rc are equal to each other and are opposite to the magnetic sensing directions of the resistor side Ra and the resistor side Rd, the resistor side Ra and the resistor side Rb are connected in series, and the resistor side Rc and the resistor side Rd are connected in series and in parallel to the resistor side Ra and the resistor side Rb to form a Wheatstone bridge circuit. The first magneto-electric converter 50a is assembled and arranged on an arm 24c1, at least a portion of which is included in the conductor 24, and among the unit areas E in which at least some of the multiple magneto-resistance elements 51 forming each of the resistance sides Ra to Rd are arranged adjacent to each other in the width direction, the width w of the first magneto-electric converter 50a, which is the distance between the center of gravity of the unit area E of the resistance sides Ra to Rd located on one side in the width direction of the arm 24c1 of the conductor 24 and the center of gravity of the unit area E of the resistance sides Ra to Rd located on the other side, is 0.3 times or less the width W of the arm 24c1. Since the width w of the first magnetic-electric conversion unit 50a is 0.3 times or less the width of the arm 24c1 of the conductor 24, the imbalance in the magnetic susceptibility of each of the resistor sides Ra to Rd due to the magnetic field distribution on the arm 24c1 in the width direction of the arm 24c1 is reduced, and the common-mode voltage Vcm included in the output voltage output from the connection point of the resistor sides Ra and Rb and the connection point of the resistor sides Rc and Rd can be suppressed.

[0091] Moreover, the current sensor 100 according to the present embodiment includes the conductor 24 through which the current to be measured flows, and the magnetic sensor 50. This makes it possible to suppress di / dt noise due to induced electromotive force and / or differential amplification noise associated with the spread of the magnetic field distribution.

[0092] The conductor 24 through which the current to be measured flows includes an arm 24c1, an arm 24c2 spaced apart from the arm 24c1 in the width direction, and a connecting portion 24c3 connecting the arm 24c1 and the arm 24c2, and the arm 24c1 and the arm 24c2 extend on the same side with respect to the connecting portion 24c3. Here, the distance from the surface of the conductor 24 on the side having the magnetoelectric conversion unit 50a to the magnetic sensing surface of the magnetoresistance element 51 (i.e., the height of the magnetic sensing surface of the magnetoresistance element 51 from the surface of the conductor 24) may be greater than 0.16 mm and may be equal to or less than 3.5 mm. This makes it possible to balance the suppression of di / dt noise due to induced electromotive force and / or differential amplification noise associated with the spread of the magnetic field distribution with the sensitivity of the magnetoresistance element.

[0093] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0094] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0095] 9...package, 10...base, 11...main body, 12, 14...protruding portion, 15, 16, 17...device terminal, 15a, 16a...terminal portion, 17...device terminal, 17a...terminal portion, 18...insulating member, 24...conductor, 24a, 24e...terminal portion, 24b, 24d...body portion, 24c...curved portion, 24c1, 24c2...arm, 24c3...connecting portion, 24e...current terminal, 44...signal processing device, 50...magnetic sensor, 50a...first magnetoelectric conversion portion, 50b...second magnetoelectric conversion portion, 51 (51a to 51h)...magnetic resistance element, 51o...fixed layer, 5 1p...tunnel layer, 51q...free layer, 51r...cap layer, 51s...electrode rod, 52, 53...electrode piece, 60...magnetic sensor, 61...substrate, 62...magnetoelectric conversion unit, 63...signal processing device, 100, 110...current sensor, E...unit area (planar area, three-dimensional area), Ea1 to Ea4, Eb1 to Eb4, Ec1 to Ec4, Ed1 to Ed4, Ee1 to Ee4, Ef1 to Ef4, Eg1 to Eg4, Eh1 to Eh4...unit area, GND...ground terminal, Np1, Np2...output terminal, Ra to Rh...resistance side, VDD...power supply terminal.

Claims

1. a first magnetoelectric converter including a first resistor side, a second resistor side, a third resistor side, and a fourth resistor side, each formed by connecting a plurality of magnetic resistance elements in series, the magnetic sensing directions of the first resistor side and the fourth resistor side being equal to each other, the magnetic sensing directions of the second resistor side and the third resistor side being equal to each other and opposite to the magnetic sensing directions of the first resistor side and the fourth resistor side, the first resistor side and the second resistor side being connected in series, the third resistor side and the fourth resistor side being connected in series and in parallel to the first resistor side and the second resistor side, and assembled into a Wheatstone bridge circuit, the first magnetoelectric converter being disposed on a first arm at least a portion of which is included in a conductor; A magnetic sensor, in which the width of the first magneto-electric converter, which is the distance between the center of gravity of the unit area of ​​the resistive side located on one side in the width direction of the first arm and the center of gravity of the unit area of ​​the resistive side located on the other side, among unit areas in which at least some of the multiple magneto-resistive elements forming the first resistance side to the fourth resistance side, are arranged adjacent to each other in the width direction, is 0.3 times or less the width of the first arm.

2. the conductor further includes a second arm that is spaced apart from the first arm in the width direction, and a current is input to one of the first arm and the second arm and the current is output from the other arm, The magnetic sensor according to claim 1 , wherein the first magneto-electric converter including the first resistance side to the fourth resistance side is located closer to the second arm than a center line of the first arm in the width direction.

3. the conductor further includes a second arm that is spaced apart from the first arm in the width direction, and a current is input to one of the first arm and the second arm and the current is output from the other arm, The magnetic sensor of claim 1, wherein a center of the first magnetoelectric conversion part including the first resistance side to the fourth resistance side is located on the second arm side in the width direction relative to a maximum position of a magnetic field generated on the first arm when the current is conducted through the conductor.

4. The magnetic sensor according to claim 1 , wherein the unit areas of the first resistor side to the fourth resistor side are arranged in the width direction.

5. Each of the first resistor side to the fourth resistor side includes a first unit area and a second unit area that are respectively arranged on one side and the other side of a conduction direction of a current flowing through the conductor, the first unit areas of the first resistor side to the fourth resistor side are arranged in the width direction, The magnetic sensor according to claim 4 , wherein the second unit areas of each of the first to fourth resistor sides are arranged in a reverse order to the first unit areas in the width direction.

6. Each of the first resistor side to the fourth resistor side further includes a third unit area and a fourth unit area respectively disposed on one side and the other side of the current conduction direction, the third unit regions of the first resistor side to the fourth resistor side are arranged in the width direction, The magnetic sensor according to claim 5 , wherein the fourth unit areas of the first to fourth resistor sides are arranged in a reverse order to the third unit areas in the width direction.

7. The magnetic sensor according to claim 5 , wherein the first unit area and the second unit area included in each of the first to fourth resistor sides are arranged on the first arm with 180° rotational symmetry.

8. The magnetic sensor according to claim 1 , wherein at least a portion of the magnetoresistance elements are arranged in a three-dimensional array within the unit area.

9. The magnetic sensor according to claim 1 , wherein the plurality of magnetoresistance elements are tunneling magnetoresistance elements or giant magnetoresistance elements.

10. The magnetic sensor according to claim 1 , wherein magnetic sensing directions of the first resistor side to the fourth resistor side are parallel to the width direction.

11. 3. The magnetic sensor of claim 2, further comprising a second magnetoelectric converter including a fifth resistor side, a sixth resistor side, a seventh resistor side, and an eighth resistor side, each formed by connecting a plurality of magnetic resistance elements in series, wherein the fifth resistor side and the eighth resistor side have the same magnetic sensing directions, the sixth resistor side and the seventh resistor side have the same magnetic sensing directions and are opposite to the magnetic sensing directions of the fifth resistor side and the eighth resistor side, the fifth resistor side and the sixth resistor side are connected in series, and the seventh resistor side and the eighth resistor side are connected in series and in parallel to the fifth resistor side and the sixth resistor side, forming a Wheatstone bridge circuit, and at least a portion of the second magnetoelectric converter is disposed on the second arm and connected in parallel to the first magnetoelectric converter.

12. 12. The magnetic sensor according to claim 11, wherein unit areas in which at least some of the multiple magnetic resistance elements forming the fifth resistance side, the sixth resistance side, the seventh resistance side, and the eighth resistance side are arranged adjacent to each other are arranged in the width direction.

13. Each of the fifth to eighth resistor sides includes a fifth unit area and a sixth unit area disposed on one side and the other side of the current conduction direction, respectively, the fifth unit areas of the fifth resistor side to the eighth resistor side are arranged in the width direction, The magnetic sensor according to claim 12 , wherein the sixth unit areas of each of the fifth to eighth resistor sides are arranged in a reverse order to the fifth unit areas in the width direction.

14. Each of the fifth resistance side to the eighth resistance side further includes a seventh unit area and an eighth unit area respectively arranged on one side and the other side of the current conduction direction, the seventh unit regions of the fifth resistor side to the eighth resistor side are arranged in the width direction, The magnetic sensor according to claim 13 , wherein the eighth unit areas of each of the fifth to eighth resistor sides are arranged in a reverse order to the seventh unit areas in the width direction.

15. A magnetic sensor according to any one of claims 1 to 14, The conductor through which the current to be measured flows; A current sensor comprising:

16. The conductor through which the current to be measured flows is a first arm, a second arm spaced apart from the first arm in the width direction, and a connecting portion connecting the first arm and the second arm; The first arm and the second arm extend on the same side with respect to the connecting portion.

16. The current sensor of claim 15.

17. The current sensor according to claim 15 , wherein a distance from a surface of the conductor on the side including the magnetoelectric conversion portion to the magnetic sensing surface is greater than 0.16 mm.

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