MAGNETIC SENSOR AND CURRENT DETECTION DEVICE

A magnetic sensor 50 includes: a resistor arm Ra having: a plurality of magneto resistive elements 51a; an electrode piece 52a which connects upper surfaces of two magneto resistive elements 51a; and an electrode piece 53a which connects lower surfaces of two magneto resistive elements 51a, where the plurality of magneto resistive elements 51a are alternately connected in array sequence by the electrode pieces 52a and 53a; and a resistor arm Rb having: a plurality of magneto resistive elements 51b; an electrode piece 52b which connects upper surfaces of two magneto resistive elements 51b; and an electrode piece 53b which connects lower surfaces of two magneto resistive elements 51b, where the plurality of magneto resistive elements 51b are alternately connected in array sequence by the electrode pieces 52b and 53b.

The contents of the following patent application(s) are incorporated herein by reference:NO. 2023-054883 filed in JP on Mar. 30, 2023NO. 2023-200559 filed in JP on Nov. 28, 2023

BACKGROUND

1. Technical Field

The present invention relates to a magnetic sensor and a current detection device.

2. Related Art

A magnetic sensor is known which has a Wheatstone bridge circuit composed of four resistor arms each of which includes a magneto resistive element (TMR) and which detects a magnetic field intensity by inputting a drive voltage from a pair of power source nodes and obtaining a differential voltage from a pair of output nodes (see Patent Document 1). In a magnetic sensor with such a configuration, connecting a plurality of TMRs in series to constitute each of the resistor arms can improve a DC voltage resistance and an ESD voltage resistance of the magnetic sensor. However, there is a concern that, as a result of a chip area (equal to a magneto sensitive portion area) increasing, in other words, a closed loop formed by the four resistor arms increasing, and a large number of magnetic fluxes passing through the inside of the closed loop, not only an induced electromotive force is generated, resulting in a di/dt noise, but also a common-mode signal is generated due to a magnetic field distribution on the magneto sensitive portion, resulting in a differential amplification noise.Patent Document 1: International Publication No. 2015/107949

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to claims. In addition, not all combinations of features described in the embodiments are essential to a solution of the invention.

First Embodiment

FIG.1AandFIG.1Brespectively show an internal configuration of a current detection device100according to a first embodiment through a package9in a top view and a side view. Here,FIG.1Bshows a cross-sectional structure of the current detection device100with respect to a reference line inFIG.1A. It should be noted that the upward/downward direction inFIG.1Ais defined as the longitudinal direction, the rightward/leftward direction inFIG.1AandFIG.1Bis defined as the lateral direction, and the upward/downward direction inFIG.1Bis defined as the height direction. The current detection device100is a sensor which measures an amount of current by using a magnetic sensor50to detect a magnetic field generated around a conductor24as a result of a to-be-measured current flowing through the conductor24, and can suppress especially a di/dt noise due to an induced electromotive force and/or a differential amplification noise caused by spread of a magnetic field distribution. The current detection device100includes the package9, a base10, a plurality of device terminals17, the conductor24, the magnetic sensor50, and a signal processing device44.

The package9is a member which encapsulates therein and protects each portion constituting the current detection device100, except for two device terminals15and16included in the base10which will be described below, the plurality of device terminals17, and respective terminal portions of the conductor24. The package9is formed into a flat cuboid through molding using, for example, encapsulation resin with excellent electrical insulation such as epoxy.

The base10is a plate-like member which supports the signal processing device44and to which an insulating member18is fixed. The base10is formed of, for example, metal with high thermal conductivity into a plate, especially in order to release heat generated by the signal processing device44. The base10has a body11, protruding portions12and14, and the device terminals15and16.

The body11is a part which supports the signal processing device44. The body11has a substantially rectangular shape with its size sufficiently large to support the signal processing device44in a plan view, as one example.

The protruding portions12and14are respectively extended toward the right from one end (that is, an upper end inFIG.1A) and another end (that is, a lower end inFIG.1A) of one lateral side (that is, a right side inFIG.1A) of the body11. When the magnetic sensor50is arranged around the conductor24, the insulating member18can be fixed between the protruding portions12and14, to arrange the magnetic sensor50on the insulating member18.

The device terminals15and16are parts for outputting, to an external device, a detection result of the to-be-measured current outputted from the signal processing device44. The device terminals15and16are extended toward the left from one end (that is, an upper end inFIG.1A) and another end (that is, a lower end inFIG.1A) of another lateral side (that is, a left side inFIG.1A) of the body11. The device terminals15and16respectively have terminal portions15aand16awhich are formed at their ends by bending their ends downward by a bending process and further bending their edges horizontally.

The base10is encapsulated in the package9with the terminal portions15aand16aof the device terminals15and16protruding from a side surface of the package9.

The plurality of device terminals17, together with the device terminals15and16, are secondary conductors for outputting, to the external device, the detection result of the to-be-measured current outputted from the signal processing device44. In addition, the plurality of device terminals17, together with the device terminals15and16, are used to give a power source or an operating parameter to the signal processing device44. In the present embodiment, as one example, three device terminals17are arrayed, with their longitudinal sides being oriented in the lateral direction, at regular intervals between the device terminals15and16of the base10. The device terminals17are formed of metal into rectangular plates, and respectively have terminal portions17awhich are formed at their ends by bending their ends downward by a bending process and further bending their edges horizontally, similarly to the device terminals15and16.

The conductor24is a primary conductor which forms a current path through which the to-be-measured current flows. In the present embodiment, the conductor24has a substantially U shape in which the conductor24passes through the inside of the package9from a current terminal24awhich is provided on one side (that is, an upper side inFIG.1A) of the right side of the package9, returns to the right side, and reaches a current terminal24ewhich is provided on another side (that is, a lower side inFIG.1A) of the right side. The conductor24is formed of metal. The conductor24includes the current terminals (also simply referred to as terminal portions)24aand24e, barrels24band24d, and a curved portion24c.

The terminal portions24aand24eprotrude from the right side of the package9, and by bending their ends downward by a bending process and further bending their edges horizontally, terminals for inputting a current are formed.

The barrels24band24dare parts which connect the terminal portions24aand24eto the curved portion24c. The barrels24band24dare formed into rectangles as one example, two barrels24band24dare connected to the right side while being spaced apart from each other, and legs of the curved portion24care connected to the left side.

The curved portion24chas two legs and a connecting portion which connects these two legs. The two legs have longitudinal widths smaller than the barrels24band24d. The connecting portion of the curved portion24cis curved into a substantially circular arc, and from its both ends, the two legs extend in the lateral direction. It should be noted that the curved portion24cmay be bent into a rectangular U.

The conductor24is encapsulated in the package9with the curved portion24cbeing arranged between the protruding portions12and14of the base10and with the edges of the terminal portions24aand24eprotruding from the right side of the package9.

The magnetic sensor50is a sensor which detects a magnetic field generated by the to-be-measured current passed through the conductor24. The magnetic sensor50is configured to detect a longitudinal magnetic field (one example of a horizontal magnetic field) generated around the conductor24, and is arranged on one leg of the conductor24, as one example.

FIG.2shows a circuit configuration of a magnetic sensor50. The magnetic sensor50includes four resistor arms Ra to Rd. Here, the four resistor arms Ra to Rd are connected in a Wheatstone bridge circuit pattern. That is, one end of the resistor arm Ra is connected to one end of the resistor arm Rb to form an output terminal Np1, one end of the resistor arm Rc is connected to one end of the resistor arm Rd to form an output terminal Np2, another end of the resistor arm Ra is connected to another end of the resistor arm Rc to form a power source terminal VDD, and another end of the resistor arm Rb is connected to another end of the resistor arm Rd to form a ground terminal GND.

It should be noted that magnetic field detection directions of the resistor arm Ra and the resistor arm Rd are the same, and in the present example, they are upward (or downward) longitudinally inFIG.1A. In addition, magnetic field detection directions of the resistor arm Rb and the resistor arm Rc are the same, and in the present example, they are downward (or upward) longitudinally inFIG.1A. In addition, the magnetic field detection directions of the resistor arm Ra and the resistor arm Rd are opposite to the magnetic field detection directions of the resistor arm Rb and the resistor arm Rc. Each of the four resistor arms Ra to Rd is formed by, for example, using one magneto resistive element51or connecting a plurality of magneto resistive elements51ato51din series. It should be noted that, as a magneto resistive element, for example, a tunneling magneto resistive element or a huge magneto resistive element can be employed.

FIG.3shows a configuration of a magneto resistive element51(51ato51d) in a side view. The magneto resistive element51is an element with a resistance value varying depending on application of a magnetic field, and has a fixed layer51o, a tunnel layer51p, a free layer51q, and a cap layer51r. The fixed layer51ois a magnetic film whose direction of magnetization is fixed. The fixed layer51ois magnetized such that its magnetization is oriented in a uniaxial direction in a plane on which the magnetic film spreads (also referred to as a magneto sensitive surface) or in a direction perpendicular to the magneto sensitive surface. The direction of magnetization of the fixed layer51odefines a magnetic field detection direction of the magneto resistive element51. The tunnel layer51pis, for example, a non-magnetic insulating film with a thickness of several nanometers. The free layer51qis a magnetic film whose direction of magnetization changes depending on an external magnetic field. It should be noted that, as a material of the magnetic film, for example, an alloy containing at least one of Co, Fe, B, Ni, or Si, and more specifically, cobalt iron (CoFe), cobalt iron boron (CoFeB), or nickel iron (NiFe) can be used. The fixed layer51o, the tunnel layer51p, and the free layer51qare laminated to constitute a laminated body. Here, a current flows in the element in a laminated direction as a result of electrons moving from the fixed layer51oto the free layer51qor from the free layer51qto the fixed layer51oby tunneling through the tunnel layer51p. The cap layer51ris a member which covers the laminated body from above, and as its material, for example, an alloy containing at least one of Ta, Ru, Pt, Mn, Ir, Mg, Cu, Fe, Ni, Cr, Fe, Co, or Al, and more specifically, platinum manganese (PtMn) or iridium manganese (IrMn) can be used. It should be noted that a region around the magneto resistive element51is covered with an insulator (not shown), for example, silicon dioxide (SiO2), silicon nitride (SiN), or the like.

When the external magnetic field is applied to the magneto resistive element51, due to a magneto resistive effect (MR effect), the direction of magnetization of the free layer51qchanges depending on a direction and intensity of the magnetic field, that is, the direction of magnetization of the free layer51qchanges with respect to the direction of magnetization of the fixed layer51o, so that the resistance value between the fixed layer51oand the free layer51qvaries. Especially, when the direction of magnetization of the free layer51qis the same as the direction of magnetization of the fixed layer51o(the magnetizations of the two layers are parallel), the resistance value is small, and when the direction of magnetization of the free layer51qis opposite to the direction of magnetization of the fixed layer51o(the magnetizations of the two layers are antiparallel), the resistance value is great.

It should be noted that connecting a plurality of magneto resistive elements51in series can improve a DC voltage resistance. Here, connecting an electrode piece52to the cap layer51rvia an electrode rod51sand connecting an electrode piece53to a lower surface of the fixed layer51ocan connect the magneto resistive element51to other magneto resistive elements51via these electrode pieces52and53.

When a to-be-measured current flows through a conductor24to generate the magnetic field around the conductor24, the longitudinal magnetic field is applied to (the magneto resistive elements51ato51dincluded in) resistor arms Ra to Rd of a magnetic sensor50arranged on the conductor24, to vary their respective resistance values. For example, the resistance values of the resistor arms Ra and Rd increase (or decrease), and the resistance values of the resistor arms Rb and Rc decrease (or increase). As a result, a resistance balance between the resistor arms Ra to Rd is disrupted. Here, a magnetic field intensity can be detected by inputting a drive voltage to the power source terminal VDD with respect to the ground terminal GND and detecting a differential voltage outputted from between the output terminals Np1and Np2. It should be noted that a configuration of the magnetic sensor50will be further described below.

The magnetic sensor50is connected to a signal processing device44through wire bonding, and outputs a voltage corresponding to the detected magnetic field intensity to the signal processing device44as an output signal.

The signal processing device44is a device which processes the output signal of the magnetic sensor50to calculate an amount of the to-be-measured current passed through the conductor24. The signal processing device44may incorporate a memory, a sensitivity correction circuit, an offset correction circuit which corrects an offset of an output, an amplifying circuit which amplifies the output signal from the magnetic sensor50, and a temperature correction circuit which corrects the output according to temperature. The signal processing device44is supported on a body11of a base10, and is connected to device terminals15and16of the base10and three device terminals17through wire bonding. As a result, the signal processing device44outputs a calculation result on the amount of the to-be-measured current passed through the conductor24via the device terminals15,16, and17.

A method for manufacturing the current detection device100will be described.

First, one piece of metal plate is pressed to form a pattern of the base10, a plurality of device terminals17, and the conductor24. This pattern includes the base10, the plurality of device terminals17, and the conductor24, with their terminal portions being coupled to the inside of a rectangular frame.

Next, a step providing process is performed on the pattern, to provide steps to the device terminals15and16of the base10, the plurality of device terminals17, and the conductor24. As a result, with respect to the frame and their terminal portions coupled to the frame, the inner part of the pattern is raised.

Next, the magnetic sensor50and the signal processing device44are installed on the pattern. Here, the magnetic sensor50is arranged on one leg of the conductor24. The signal processing device44is arranged on the body11of the base10.

Next, through wire bonding, the magnetic sensor50is connected to the signal processing device44, and the signal processing device44is connected to the device terminals15,16, and17.

Next, the pattern is molded, except for the frame as well as the terminal portions of the base10, the plurality of device terminals17, and the conductor24coupled to the frame. As a result, a package9is formed, and encapsulates therein the magnetic sensor50, the signal processing device44, and the inner part of the pattern on which these are installed.

Finally, the frame exposed on the outside of the package9is cut off from the pattern. As a result, the base10, the plurality of device terminals17, and the conductor24are separated from each other, to finalize the current detection device100.

FIG.4Ashows an example of arrangement of a magnetic sensor50. The magnetic sensor50can be arranged on one of two legs of a conductor24, as described above.

Alternatively, it may be arranged on another of the two legs. In addition, it is more preferable to arrange it on each of the two legs of the conductor24because a disturbance magnetic field can be canceled. The magnetic sensor50arranged at such a position is configured to detect a horizontal magnetic field parallel to an upper surface of the conductor24(in the present example, the longitudinal magnetic field inFIG.1A).

FIG.4Bshows magnetic field detection directions of (magneto resistive elements51ato51drespectively included in) four resistor arms Ra to Rd included in the magnetic sensor50inFIG.4A. The magnetic field detection directions of the resistor arm Ra (the magneto resistive element51a) and the resistor arm Rd (the magneto resistive element51d) are the same, and in the present example, they are each one uniaxial direction parallel to the upper surface of the conductor24(indicated by open arrows in the figure). The magnetic field detection directions of the resistor arm Rb (the magneto resistive element51b) and the resistor arm Rc (the magneto resistive element51c) are the same, and in the present example, they are each another uniaxial direction parallel to the upper surface of the conductor24(indicated by filled arrows in the figure). The magnetic field detection directions of the resistor arm Ra and the resistor arm Rd are opposite to the magnetic field detection directions of the resistor arm Rb and the resistor arm Rc. This allows the magnetic sensor50to detect the horizontal magnetic field generated on the upper surface of the conductor24.

FIG.5Ashows another example of arrangement of a magnetic sensor50. The magnetic sensor50can be arranged in a region surrounded by a curved portion24cof a conductor24. Alternatively, it may be arranged near one of two legs of the conductor24, or may be arranged near each of the two legs. Especially, it is more preferable to install it near one of the two legs of the conductor24because a disturbance magnetic field can be canceled. The magnetic sensor50arranged at such a position is configured to detect a vertical magnetic field perpendicular to an upper surface of the conductor24(in the present example, the magnetic field in the height direction inFIG.1A).

It should be noted that the magnetic sensor50can be arranged near the conductor24by attaching an insulating member18to lower surfaces of protruding portions12and14of a base10to place the insulating member18between the protruding portions12and14and by supporting the magnetic sensor50on the insulating member18. It should be noted that the insulating member18is formed of, as one example, a material with a high withstand voltage such as a polyimide tape, into a film.

In addition, the curved portion24cof the conductor24may be raised with respect to barrels24band24dby providing a step in the height direction by a step providing process (for example, half punching, etching, forming, coining, or the like). As a result, a bottom surface of the curved portion24cis higher than an upper surface of the insulating member18attached to bottom surfaces of the protruding portions12and14of the base10, and a primary conductor including the conductor24and the insulating member18connected to a secondary conductor including device terminals15,16, and17are spaced apart from each other, so that a high withstand voltage can be obtained between the primary conductor and the secondary conductor in a package9.

FIG.5Bshows magnetic field detection directions of (magneto resistive elements51ato51drespectively included in) four resistor arms Ra to Rd included in the magnetic sensor50inFIG.5A. The magnetic field detection directions of the resistor arm Ra (the magneto resistive element51a) and the resistor arm Rd (the magneto resistive element51d) are the same, and in the present example, they are upward perpendicularly to the upper surface of the conductor24(indicated by open arrows in the figure). The magnetic field detection directions of the resistor arm Rb (the magneto resistive element51b) and the resistor arm Rc (the magneto resistive element51c) are the same, and in the present example, they are downward perpendicularly to the upper surface of the conductor24(indicated by filled arrows in the figure). The magnetic field detection directions of the resistor arm Ra and the resistor arm Rd are opposite to the magnetic field detection directions of the resistor arm Rb and the resistor arm Rc. This allows the magnetic sensor50to detect the vertical magnetic field generated around the conductor24.

FIG.6Ashows a principle of generation of a di/dt noise caused by induced electromotive forces. When a magnetic field (a magnetic flux density B) is applied to two wiring lines constituting a Wheatstone bridge circuit (that is, a closed loop) of a magnetic sensor50, and magnetic fluxes (ϕ=BS, where S is an area between the wiring lines) pass between the two wiring lines, the induced electromotive forces (V=−dϕ/dt=−SdB/dt) are generated in the two wiring lines such that an increase and decrease in a magnetic flux density (magnetic field intensity B/u, where u is magnetic permeability) is canceled out. When the wiring lines are parallel, leftward induced electromotive forces (indicated by open arrows in the figure) applied to an upper wiring line and rightward induced electromotive forces (indicated by filled arrows in the figure) applied to a lower wiring line by respective magnetic fluxes penetrating between the wiring lines are added together, to generate a great induced electromotive force between the two wiring lines. As a result, a noise, the so-called di/dt noise, caused by the induced electromotive forces is superimposed on an output signal of the magnetic sensor.

FIG.6Bshows a principle of suppressing the di/dt noise. A plurality of partial loops with equal areas are formed in the closed loop by twisting the two wiring lines constituting the closed loop to form twisted wires. When the magnetic field (the magnetic flux density B) is applied to the two wiring lines, and a magnetic flux passes through each of the plurality of partial loops, induced electromotive forces are generated in the wiring lines constituting each of the partial loops such that the increase and decrease in the magnetic flux density is canceled out. When the wiring lines are twisted, in each of the partial loops, a leftward induced electromotive force (indicated by an open arrow in the figure) is applied to the upper wiring line, and a rightward induced electromotive force (indicated by a filled arrow in the figure) is applied to the lower wiring line. However, in each of the two wiring lines, a direction of the induced electromotive force is changed for each of parts constituting the partial loops, so that an induced electromotive force applied to the entire wiring line is suppressed. It should be noted that directions of the induced electromotive forces generated in each of the loops are also referred to as polarities. Especially, when an even number of partial loops are formed, the induced electromotive force applied to the entire wiring line is canceled out. In this manner, providing the even number of partial loops with equal loop areas and opposite polarities in the Wheatstone bridge circuit of the magnetic sensor50can cancel out or strongly suppress the di/dt noise.

FIG.7shows a configuration of a magnetic sensor50according to the first embodiment in a perspective view. The magnetic sensor50includes four resistor arms Ra to Rd assembled into a twisted Wheatstone bridge circuit. It should be noted that the magneto resistive elements51ato51drespectively included in the resistor arms Ra to Rd are configured as described above.

The resistor arm Ra has a plurality of magneto resistive elements51a, a plurality of electrode pieces52a, and a plurality of electrode pieces53a. The plurality of magneto resistive elements51aare arrayed on one surface such as an upper surface of the conductor24, for example. Each of the plurality of electrode pieces52ais a narrow piece-like member formed of a conductive metal, and connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51a(that is, upper surfaces of cap layers51r). Each of the plurality of electrode pieces53ais a wide piece-like member formed of a conductive metal, and connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51a(that is, lower surfaces of fixed layers51o), and especially, connects a lower surface of one of two magneto resistive elements51awhose upper surfaces are connected by an electrode piece52ato a lower surface of another magneto resistive element51aof the plurality of magneto resistive elements51a.

The plurality of magneto resistive elements51aare alternately connected in array sequence by electrode pieces52aand electrode pieces53a. In other words, an upper surface of a first magneto resistive element51ais connected to an upper surface of a second magneto resistive element51aby the electrode piece52a, a lower surface of the second magneto resistive element51ais connected to a lower surface of a third magneto resistive element51aby the electrode piece53a, an upper surface of the third magneto resistive element51ais connected to an upper surface of a fourth magneto resistive element51aby the electrode piece52a, and a lower surface of the fourth magneto resistive element51ais connected to a lower surface of a fifth magneto resistive element51aby the electrode piece53a, so that the plurality of (in the present example, five) magneto resistive elements51aare linked in series.

The resistor arm Rb has a plurality of magneto resistive elements51b, a plurality of electrode pieces52b, and a plurality of electrode pieces53b. The plurality of magneto resistive elements51bare arrayed on one surface such as the upper surface of the conductor24. Each of the plurality of electrode pieces52band the plurality of electrode pieces53bis formed similarly to the plurality of electrode pieces52aand the plurality of electrode pieces53a, and connects upper surfaces or lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51b. Here, each of the plurality of electrode pieces53bconnects a lower surface of one of two magneto resistive elements51bwhose upper surfaces are connected by an electrode piece52bto a lower surface of another magneto resistive element51bof the plurality of magneto resistive elements51b.

The plurality of magneto resistive elements51bare alternately connected in array sequence by electrode pieces52band electrode pieces53b. In other words, a lower surface of a first magneto resistive element51bis connected to a lower surface of a second magneto resistive element51bby the electrode piece53b, an upper surface of the second magneto resistive element51bis connected to an upper surface of a third magneto resistive element51bby the electrode piece52b, a lower surface of the third magneto resistive element51bis connected to a lower surface of a fourth magneto resistive element51bby the electrode piece53b, and an upper surface of the fourth magneto resistive element51bis connected to an upper surface of a fifth magneto resistive element51bby the electrode piece52b, so that the plurality of (in the present example, five) magneto resistive elements51bare linked in series.

Here, the resistor arm Ra and the resistor arm Rb include an intersecting part50awhere their respective electrode pieces intersect three-dimensionally. In the intersecting part50a, the electrode piece52aand the electrode piece52bare arranged to be parallel to each other with their longitudinal sides being oriented in the rightward/leftward direction in the drawing, and the electrode piece53aand the electrode piece53bare arranged to be parallel to each other with their longitudinal sides being oriented in the upward/downward direction in the drawing. That is, the electrode piece52aand the electrode piece52bare arranged in a direction in which the electrode piece52aand the electrode piece52bintersect with the electrode piece53aand the electrode piece53b. Here, an angle at which the electrode piece52aand the electrode piece52bintersect with the electrode piece53aand the electrode piece53bmay be 90 degrees. Furthermore, the electrode piece52ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53b, and the electrode piece53ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece52b. As a result, the resistor arm Ra and the resistor arm Rb can be assembled on one surface in a twisted pattern and disposed in a limited region.

Furthermore, a length of the electrode piece52aand a length of the electrode piece52bare equal to each other, and a length of the electrode piece53aand a length of the electrode piece53bare equal to each other. Here, the lengths of the electrode pieces52aand53aare defined as lengths in directions in which two magneto resistive elements51athat are adjacent to each other are connected. In addition, the lengths of the electrode pieces52band53bare defined as lengths in directions in which two magneto resistive elements51bthat are adjacent to each other are connected. As a result, when the intersecting part50ais viewed from the X axis direction, the Y axis direction, or any direction in the XY plane, a pair of partial loops with equal loop areas and opposite polarities are formed.

It should be noted that the resistor arm Ra and the resistor arm Rb may include a plurality of sets of intersecting parts50athat are coupled to each other. In the present example, an intersecting part50a2is coupled to the intersecting part50adescribed above, similarly to which the intersecting part50a2is configured. As a result, the resistor arm Ra has an even number of electrode pieces52aand electrode pieces53a(in the present example, two for each), the resistor arm Rb has an even number of electrode pieces52band electrode pieces53b(in the present example, two for each).

Here, the intersecting part50aincludes a partial loop formed of four electrode pieces52a,53a,52b, and53bwhen viewed in the Z axis direction, and is further coupled to the intersecting part50a2, so that a second partial loop is formed of four electrode pieces52a,53a,52b, and53bbetween the intersecting parts50aand50a2. In other words, coupling a plurality of intersecting parts50aforms one or more pairs of partial loops with equal loop areas and opposite polarities when viewed in the Z axis direction.

The resistor arm Rc has a plurality of magneto resistive elements51c, a plurality of electrode pieces52c, and a plurality of electrode pieces53c. The plurality of magneto resistive elements51care arrayed on one surface such as the upper surface of the conductor24. Each of the plurality of electrode pieces52cis a narrow piece-like member formed of a conductive metal, and connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51c(that is, upper surfaces of cap layers51r). Each of the plurality of electrode pieces53cis a wide piece-like member formed of a conductive metal, and connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51c(that is, lower surfaces of fixed layers51o), and especially, connects a lower surface of one of the two magneto resistive elements51cwhose upper surfaces are connected by an electrode piece52cto a lower surface of another magneto resistive element51cof the plurality of magneto resistive elements51c.

The plurality of magneto resistive elements51care alternately connected in array sequence by electrode pieces52cand electrode pieces53c. Connection between the plurality of magneto resistive elements51cby the electrode pieces52cand the electrode pieces53cis similar to connection between the plurality of magneto resistive elements51bby the electrode pieces52band the electrode pieces53b. As a result, the plurality of (in the present example, five) magneto resistive elements51care linked in series.

The resistor arm Rd has a plurality of magneto resistive elements51d, a plurality of electrode pieces52d, and a plurality of electrode pieces53d. The plurality of magneto resistive elements51dare arrayed on one surface such as the upper surface of the conductor24. Each of the plurality of electrode pieces52dand the plurality of electrode pieces53dis formed similarly to the plurality of electrode pieces52cand the plurality of electrode pieces53c, and connects upper surfaces or lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51d. Here, each of the plurality of electrode pieces53dconnects a lower surface of one of the two magneto resistive elements51dwhose upper surfaces are connected by the electrode piece52dto a lower surface of another magneto resistive element51dof the plurality of magneto resistive elements51d.

The plurality of magneto resistive elements51dare alternately connected in array sequence by electrode pieces52dand electrode pieces53d. Connection between the plurality of magneto resistive elements51dby the electrode pieces52dand the electrode pieces53dis similar to connection between the plurality of magneto resistive elements51aby the electrode pieces52aand the electrode pieces53a. As a result, the plurality of (in the present example, five) magneto resistive elements51dare linked in series.

Here, the resistor arm Rc and the resistor arm Rd include an intersecting part50cwhere their respective electrode pieces intersect three-dimensionally. In the intersecting part50c, the electrode piece52cand the electrode piece52dare arranged to be parallel to each other with their longitudinal sides being oriented in the rightward/leftward direction in the drawing, and the electrode piece53cand the electrode piece53dare arranged to be parallel to each other with their longitudinal sides being oriented in the upward/downward direction in the drawing. That is, the electrode piece52cand the electrode piece52dare arranged in a direction in which the electrode piece52cand the electrode piece52dintersect with the electrode piece53cand the electrode piece53d. Here, an angle at which the electrode piece52cand the electrode piece52dintersect with the electrode piece53cand the electrode piece53dmay be 90 degrees. Furthermore, the electrode piece52cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53d, and the electrode piece53cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece52d. As a result, the resistor arm Rc and the resistor arm Rd can be assembled on one surface in a twisted pattern and disposed in a limited region.

Furthermore, a length of the electrode piece52cand a length of the electrode piece52dare equal to each other, and a length of the electrode piece53cand a length of the electrode piece53dare equal to each other. Here, the lengths of the electrode pieces52cand53care defined as lengths in directions in which two magneto resistive elements51cthat are adjacent to each other are connected. In addition, the lengths of the electrode pieces52dand53dare defined as lengths in directions in which two magneto resistive elements51dthat are adjacent to each other are connected. As a result, when the intersecting part50cis viewed from the X axis direction, the Y axis direction, or any direction in the XY plane, a pair of partial loops with equal loop areas and opposite polarities are formed.

It should be noted that the resistor arm Rc and the resistor arm Rd may include a plurality of sets of intersecting parts50cthat are coupled to each other. In the present example, an intersecting part50c2is coupled to the intersecting part50cdescribed above, similarly to which the intersecting part50c2is configured. As a result, the resistor arm Rc has an even number of electrode pieces52cand electrode pieces53c(in the present example, two for each), the resistor arm Rb has an even number of electrode pieces52dand electrode pieces53d(in the present example, two for each).

Here, the intersecting part50cincludes a partial loop formed of four electrode pieces52c,53c,52d, and53dwhen viewed in the Z axis direction, and is further coupled to the intersecting part50c2, so that a second partial loop is formed of four electrode pieces52c,53c,52d, and53dbetween the intersecting parts50cand50c2. In other words, coupling a plurality of intersecting parts50cforms one or more pairs of partial loops with equal loop areas and opposite polarities when viewed in the Z axis direction.

FIG.8Ashows a principle of suppressing a di/dt noise caused by application of an X direction magnetic field. As one example, when a magnetic flux (solid arrow) oriented in the +X direction is applied to resistor arms Ra and Rb, induced electromotive forces directed leftward (open arrow) and downward (filled arrow) in the drawing are respectively generated in the electrode pieces52aand53bwhich form a partial loop when viewed in the X direction, induced electromotive forces directed leftward (open arrow) and downward (filled arrow) in the drawing are respectively generated in the electrode pieces52band53awhich form an adjacent partial loop, and induced electromotive forces directed leftward (open arrow) and downward (filled arrow) in the drawing are respectively generated in the electrode pieces52aand53bwhich form a further adjacent partial loop. Here, the lengths of the electrode pieces52a,52b,53a, and53b(especially, lengths of parts which form the partial loops) are equal, and the electrode pieces52aand52band the electrode pieces53aand53bare connected via an output terminal Np1, so that the induced electromotive forces generated in the electrode piece52aand the electrode piece53bare canceled out, and the induced electromotive forces generated in the electrode piece52band the electrode piece53aare canceled out.

It should be noted that, also when the X direction magnetic field is applied to resistor arms Rc and Rd, induced electromotive forces generated in electrode pieces constituting the resistor arms Rc and Rd are canceled out based on a similar principle.

FIG.8Bshows a principle of suppressing a di/dt noise caused by application of a Y direction magnetic field. As one example, when magnetic fluxes (solid arrow and dotted arrow) oriented in the +Y direction are applied to the resistor arms Ra and Rb, induced electromotive forces directed leftward (filled arrow) in the drawing and upward (filled arrow) in the drawing are respectively generated in the electrode pieces52aand53bwhich form a partial loop when viewed in the Y direction, and induced electromotive forces directed leftward (open arrow) in the drawing and upward (open arrow) in the drawing are respectively generated in the electrode pieces52band53awhich form an adjacent partial loop. Here, the lengths of the electrode pieces52a,52b,53a, and53b(especially, lengths of parts which form the partial loops) are equal, so that two partial loops have equal loop areas, and the electrode pieces52a,52b,53a, and53bare connected in a twisted pattern, so that the two partial loops have opposite polarities. As a result, the induced electromotive force (filled arrow) generated in the electrode piece52aby the magnetic flux (solid arrow) and the induced electromotive force (open arrow) generated in the electrode piece53aby the magnetic flux (dotted arrow) are canceled out, and the induced electromotive force (filled arrow) generated in in the electrode piece53bby the magnetic flux (solid arrow) and the induced electromotive force (open arrow) generated in the electrode piece52bby the magnetic flux (dotted arrow) are canceled out.

It should be noted that the resistor arms Ra and Rb include a plurality of electrode pieces52a,52b,53a, and53b, so that a plurality of pairs of partial loops having opposite polarities are formed. As a result, the induced electromotive forces applied to the entire resistor arms Ra and Rb are canceled out. In addition, also when the Y direction magnetic field is applied to the resistor arms Rc and Rd, induced electromotive forces generated in electrode pieces constituting the resistor arms Rc and Rd are canceled out based on a similar principle.

FIG.8Cshows a principle of suppressing a di/dt noise caused by application of a Z direction magnetic field. As one example, when magnetic fluxes (solid arrow and dotted arrow) oriented in the −Z direction are applied to the resistor arms Ra and Rb, induced electromotive forces directed rightward (open arrow), upward (open arrow), leftward (open arrow), and downward (open arrow) in the drawing are respectively generated in the electrode pieces52a,53a,52b, and53bwhich form a partial loop when viewed in the Z direction, and induced electromotive forces directed rightward (filled arrow), upward (filled arrow), leftward (filled arrow), and downward (filled arrow) in the drawing are respectively generated in the electrode pieces52b,53b,52a, and53awhich form an adjacent partial loop. Here, the lengths of the electrode pieces52a,52b,53a, and53b(especially, lengths of parts which form the partial loops) are equal, and the electrode pieces52a,52b,53a, and53bare connected in a twisted pattern, so that two partial loops have opposite polarities. As a result, the induced electromotive force (open arrow) generated in the electrode piece52bby the magnetic flux (solid arrow) and the induced electromotive force (filled arrow) generated in the electrode piece52bby the magnetic flux (dotted arrow) are canceled out, and the induced electromotive force (open arrow) generated in in the electrode piece53aby the magnetic flux (solid arrow) and the induced electromotive force (filled arrow) generated in the electrode piece53aby the magnetic flux (dotted arrow) are also canceled out.

It should be noted that, in other electrode pieces as well, induced electromotive forces generated by magnetic fluxes respectively applied to two adjacent partial loops are canceled out based on a similar principle. As a result, the induced electromotive forces applied to the entire resistor arms Ra and Rb are canceled out. In addition, also when the Z direction magnetic field is applied to the resistor arms Rc and Rd, induced electromotive forces generated in electrode pieces constituting the resistor arms Rc and Rd are canceled out based on a similar principle.

As described above, the resistor arms Ra to Rd are connected in a Wheatstone bridge circuit pattern. One end of the resistor arm Ra (the end at the top right of the drawing) is connected to one end of the resistor arm Rb (the end at the top right of the drawing) to form the output terminal Np1, one end of the resistor arm Rc (the end at the top right of the drawing) is connected to one end of the resistor arm Rd (the end at the top right of the drawing) to form an output terminal Np2, another end of the resistor arm Ra (the end at the bottom left of the drawing) is connected to another end of the resistor arm Rc (the end at the bottom left of the drawing) to form a power source terminal VDD, and another end of the resistor arm Rb (the end at the bottom left of the drawing) is connected to another end of the resistor arm Rd (the end at the bottom left of the drawing) to form a ground terminal GND. Here, magnetic field detection directions of a magneto resistive element51aand a magneto resistive element51dare the same, magnetic field detection directions of a magneto resistive element51band a magneto resistive element51care the same, and the magnetic field detection directions of the magneto resistive element51aand the magneto resistive element51dare opposite to the magnetic field detection directions of the magneto resistive element51band the magneto resistive element51c.

When a magnetic field is applied to the magneto resistive elements51ato51dincluded in the resistor arms Ra to Rd of the magnetic sensor50, for example, when a magnetic field is applied in the same direction as the magnetic field detection directions of the magneto resistive element51aand the magneto resistive element51d(a direction opposite to the magnetic field detection directions of the magneto resistive element51band the magneto resistive element51c), resistance values of the resistor arm Ra and the resistor arm Rd respectively including the magneto resistive element51aand the magneto resistive element51ddecrease, and resistance values of the resistor arm Rb and the resistor arm Rc respectively including the magneto resistive element51band the magneto resistive element51cincrease, so that resistance balance between the resistor arms Ra to Rd is disrupted. Therefore, a magnetic field intensity can be detected by inputting a drive voltage to the power source terminal VDD with respect to the ground terminal GND and detecting a differential voltage outputted from between the output terminals Np1and Np2.

The magnetic sensor50according to the first embodiment includes: a first resistor arm Ra having: a plurality of first magneto resistive elements51awhich are arrayed on one surface; a first electrode piece52awhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of first magneto resistive elements51a; and a second electrode piece53awhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of first magneto resistive elements51a, where the plurality of first magneto resistive elements51aare alternately connected in array sequence by the first electrode piece52aand the second electrode piece53a; and a second resistor arm Rb having: a plurality of second magneto resistive elements51bwhich are arrayed on the one surface; a third electrode piece52bwhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of second magneto resistive elements51b; and a fourth electrode piece53bwhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of second magneto resistive elements51b, where the plurality of second magneto resistive elements51bare alternately connected in array sequence by the third electrode piece52band the fourth electrode piece53b, where the magnetic sensor50includes an intersecting part50ain which the first electrode piece52ais arranged to be upwardly/downwardly spaced apart from and intersect with the fourth electrode piece53band the second electrode piece53ais arranged to be upwardly/downwardly spaced apart from and intersect with the third electrode piece52b.

According to this, the first resistor arm Ra having the first magneto resistive elements51awhich are arrayed on one surface and the second resistor arm Rb having the second magneto resistive elements51bwhich are arrayed on the same one surface are assembled in a twisted pattern, with the first electrode piece52awhich connects upper surfaces of two first magneto resistive elements51abeing upwardly/downwardly spaced apart from and intersect with the fourth electrode piece53bwhich connects lower surfaces of two second magneto resistive elements51b, and with the second electrode piece53awhich connects lower surfaces of two first magneto resistive elements51abeing upwardly/downwardly spaced apart from and intersect with the third electrode piece52bwhich connects upper surfaces of two second magneto resistive elements51b, so that two partial loops with opposite polarities including a partial loop formed by the first electrode piece52aand the fourth electrode piece53band a partial loop formed by the second electrode piece53aand the third electrode piece52bare formed when the first resistor arm Ra and the second resistor arm Rb are connected, and it is possible to cancel out the noise caused by the induced electromotive force for a time when the magnetic field is applied. Furthermore, assembling the first resistor arm Ra and the second resistor arm Rb in a twisted pattern can decrease a unit area in which arrangement can be made, thereby reducing an influence of a gradient of the magnetic field intensity, so that a common-mode voltage can be suppressed.

The current detection device100according to the first embodiment includes: a conductor24through which a to-be-measured current flows; and the magnetic sensor50which is arranged on the conductor24or near the conductor24. As a result, it is possible to suppress the di/dt noise caused by the induced electromotive force and the common-mode noise caused by the gradient of the magnetic field intensity.

It should be noted that, in the magnetic sensor50according to the first embodiment, the resistor arms Ra and Rb are assembled in a twisted pattern and the resistor arms Rc and Rd are assembled in a twisted pattern, but alternatively, the resistor arms Ra and Rc may be assembled in a twisted pattern and the resistor arms Rb and Rd may be assembled in a twisted pattern, or the resistor arms Ra and Rd may be assembled in a twisted pattern and the resistor arms Rb and Rc may be assembled in a twisted pattern.

Second Embodiment

A current detection device according to a second embodiment is a sensor which measures an amount of current by using a magnetic sensor59to detect a magnetic field generated around a conductor24as a result of a to-be-measured current flowing through the conductor24, and can suppress especially a di/dt noise due to an induced electromotive force and/or a differential amplification noise caused by spread of a magnetic field distribution. The current detection device can be configured similarly to the current detection device100according to the first embodiment by using the magnetic sensor59instead of a magnetic sensor50.

FIG.9shows a configuration of the magnetic sensor59according to the second embodiment in a perspective view. The magnetic sensor59includes four resistor arms Ra to Rd assembled into a four-braid Wheatstone bridge circuit. Here, the four resistor arms Ra to Rd include unitary units59aand59bwhich partially constitute them, and these unitary units59aand59bcan be alternately coupled to be extended in the X axis direction, or can be extended in the X axis direction and then folded back to be further extended. In the present example, they include two unitary units59aand one unitary unit59bcoupled therebetween. It should be noted that magneto resistive elements51ato51drespectively included in the resistor arms Ra to Rd are configured as described above.

The resistor arm Ra has a plurality of magneto resistive elements51aand electrode pieces52a,53a,54a, and55a. The plurality of magneto resistive elements51aare arrayed on one surface such as an upper surface of the conductor24, for example. Each of the electrode pieces52aand54ais a narrow piece-like member formed of a conductive metal, and connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51a(that is, upper surfaces of cap layers51r). Each of the electrode pieces53aand55ais a wide piece-like member formed of a conductive metal, and connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51a(that is, lower surfaces of fixed layers51o), and especially, they connects a lower surface of one of two magneto resistive elements51awhose upper surfaces are connected by electrode pieces52aand54ato a lower surface of another magneto resistive element51aof the plurality of magneto resistive elements51a.

FIG.10AandFIG.10Brespectively show a configuration of a unitary unit59aof the magnetic sensor59in a top view and a perspective view. In the unitary unit59a, a plurality of magneto resistive elements51aare alternately connected in array sequence by electrode pieces52aand53a. In other words, a lower surface of a first magneto resistive element51a(a first element from the left of the top row inFIG.10A) is connected to a lower surface of a second magneto resistive element51aby an electrode piece53a, an upper surface of the second magneto resistive element51ais connected to an upper surface of a third magneto resistive element51aby an electrode piece52a, and a lower surface of the third magneto resistive element51ais connected to a lower surface of a fourth magneto resistive element51a(a second element from the right of the bottom row inFIG.10A) by an electrode piece53a, so that four magneto resistive elements51aare linked in series.

FIG.11AandFIG.11Brespectively show a configuration of a unitary unit59bof the magnetic sensor59in a top view and a perspective view. In the unitary unit59b, a plurality of magneto resistive elements51aare alternately connected in array sequence by electrode pieces54aand55a. In other words, an upper surface of a first magneto resistive element51a(a first element from the left of the bottom row inFIG.11A) is connected to an upper surface of a second magneto resistive element51aby an electrode piece54a, a lower surface of the second magneto resistive element51ais connected to a lower surface of a third magneto resistive element51aby an electrode piece55a, and an upper surface of the third magneto resistive element51ais connected to an upper surface of a fourth magneto resistive element51a(a second element from the right of the top row inFIG.11A) by an electrode piece54a, so that four magneto resistive elements51aare linked in series.

A resistor arm Rb has a plurality of magneto resistive elements51band electrode pieces52b,53b,54b, and55b. The plurality of magneto resistive elements51bare arrayed on one surface such as an upper surface of the conductor24. Each of the electrode pieces52band54bis formed similarly to electrode pieces52aand54a, and connects upper surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51b. Each of the electrode pieces53band55bis formed similarly to electrode pieces53aand55a, and connects lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51b. Here, the plurality of electrode pieces53band55bconnect a lower surface of one of two magneto resistive elements51bwhose upper surfaces are connected by the electrode pieces52band54bto a lower surface of another magneto resistive element51bof the plurality of magneto resistive elements51b.

In the unitary unit59a(seeFIG.10AandFIG.10B), the plurality of magneto resistive elements51bare alternately connected in array sequence by the electrode pieces54band55b. In other words, an upper surface of a first magneto resistive element51b(a second element from the left of the bottom row inFIG.10A) is connected to an upper surface of a second magneto resistive element51bby an electrode piece54b, a lower surface of the second magneto resistive element51bis connected to a lower surface of a third magneto resistive element51bby an electrode piece55b, and an upper surface of the third magneto resistive element51bis connected to an upper surface of a fourth magneto resistive element51b(a first element from the right of the top row inFIG.10A) by an electrode piece54b, so that four magneto resistive elements51bare linked in series.

In the unitary unit59b(seeFIG.11AandFIG.11B), the plurality of magneto resistive elements51bare alternately connected in array sequence by the electrode pieces52band53b. In other words, a lower surface of a first magneto resistive element51b(a second element from the left of the top row inFIG.11A) is connected to a lower surface of a second magneto resistive element51bby an electrode piece53b, an upper surface of the second magneto resistive element51bis connected to an upper surface of a third magneto resistive element51bby an electrode piece52b, and a lower surface of the third magneto resistive element51bis connected to a lower surface of a fourth magneto resistive element51b(a first element from the right of the bottom row inFIG.11A) by the electrode piece53b, so that four magneto resistive elements51bare linked in series.

A resistor arm Rc has a plurality of magneto resistive elements51cand electrode pieces52c,53c,54c, and55c. The plurality of magneto resistive elements51care arrayed on one surface such as the upper surface of the conductor24. Each of the electrode pieces52cand54cis formed similarly to the electrode pieces52aand54a, and connects upper surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51c. Each of the electrode pieces53cand55care formed similarly to the electrode pieces53aand55a, and connect lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51c, and especially, they connect a lower surface of one of two magneto resistive elements51cwhose upper surfaces are connected by the electrode pieces52cand54cto a lower surface of another magneto resistive element51cof the plurality of magneto resistive elements51c.

In the unitary unit59a(seeFIG.10AandFIG.10B), the plurality of magneto resistive elements51care alternately connected in array sequence by the electrode pieces52cand53c. In other words, a lower surface of a first magneto resistive element51c(a second element from the left of the top row inFIG.10A) is connected to a lower surface of a second magneto resistive element51cby an electrode piece53c, an upper surface of the second magneto resistive element51cis connected to an upper surface of a third magneto resistive element51cby an electrode piece52c, and a lower surface of the third magneto resistive element51cis connected to a lower surface of a fourth magneto resistive element51c(a first element from the right of the bottom row inFIG.10A) by the electrode piece53c, so that four magneto resistive elements51care linked in series.

In the unitary unit59b(seeFIG.11AandFIG.11B), the plurality of magneto resistive elements51care alternately connected in array sequence by the electrode pieces54cand55c. In other words, an upper surface of a first magneto resistive element51c(a second element from the left of the bottom row inFIG.11A) is connected to an upper surface of a second magneto resistive element51cby an electrode piece54c, a lower surface of the second magneto resistive element51cis connected to a lower surface of a third magneto resistive element51cby an electrode piece55c, and an upper surface of the third magneto resistive element51cis connected to an upper surface of a fourth magneto resistive element51c(a first element from the right of the top row inFIG.11A) by an electrode piece54c, so that four magneto resistive elements51care linked in series.

A resistor arm Rd has a plurality of magneto resistive elements51dand electrode pieces52d,53d,54d, and55d. The plurality of magneto resistive elements51dare arrayed on one surface such as the upper surface of the conductor24. Each of the electrode pieces52dand54dis formed similarly to the electrode pieces52aand54a, and connects upper surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51d. Each of the electrode pieces53dand55dis formed similarly to the electrode pieces53aand55a, and connects lower surfaces of two elements that are adjacent to each other and that are of the plurality of magneto resistive elements51d. Here, the plurality of electrode pieces53dand55dconnect a lower surface of one of the two magneto resistive elements51dwhose upper surfaces are connected by the electrode pieces52dand54dto a lower surface of another magneto resistive element51dof the plurality of magneto resistive elements51d.

In the unitary unit59a(seeFIG.10AandFIG.10B), the plurality of magneto resistive elements51dare alternately connected in array sequence by the electrode pieces54dand55d. In other words, an upper surface of a first magneto resistive element51d(a first element from the left of the bottom row inFIG.10A) is connected to an upper surface of a second magneto resistive element51dby an electrode piece54d, a lower surface of the second magneto resistive element51dis connected to a lower surface of a third magneto resistive element51dby an electrode piece55d, and an upper surface of the third magneto resistive element51dis connected to an upper surface of a fourth magneto resistive element51d(a second element from the right of the top row inFIG.10A) by an electrode piece54d, so that four magneto resistive elements51dare linked in series.

In the unitary unit59b(seeFIG.11AandFIG.11B), the plurality of magneto resistive elements51dare alternately connected in array sequence by the electrode pieces52dand53d. In other words, a lower surface of a first magneto resistive element51d(a first element from the left of the top row inFIG.11A) is connected to a lower surface of a second magneto resistive element51dby an electrode piece53d, an upper surface of the second magneto resistive element51dis connected to an upper surface of a third magneto resistive element51dby an electrode piece52d, and a lower surface of the third magneto resistive element51dis connected to a lower surface of a fourth magneto resistive element51d(a second element from the right of the bottom row inFIG.11A) by an electrode piece53d, so that four magneto resistive elements51dare linked in series.

Here, the unitary unit59a(seeFIG.10A) includes the resistor arms Ra and Rc which extend in parallel with each other toward the bottom right of the drawing and the resistor arms Rb and Rd which extend in parallel with each other toward the top right of the drawing, and includes an intersecting part59a0where the resistor arms Ra and Rc are arranged in a direction in which the resistor arms Ra and Rc intersect with the resistor arms Rb and Rd and where the resistor arms Ra and Rc alternately intersect with the resistor arms Rb and Rd upwardly/downwardly. An angle at which the resistor arms Ra and Rc intersect with the resistor arms Rb and Rd may be 90 degrees. In the intersecting part59a0, the electrode piece52ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece55d, the electrode piece53ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece54b, the electrode piece52cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece55b, and the electrode piece53cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece54d. As a result, the resistor arms Ra to Rd can be assembled on one surface in a four-braid pattern and disposed in a limited region.

Furthermore, outside the intersecting part59a0, such as a coupling part between the unitary units59aand59bor a coupling part between the unitary units59aand59band the terminals VDD, GND, NP1, and NP2, the electrode piece53ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece54c, the electrode piece53bis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece54d, the electrode piece53cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece54a, and the electrode piece53dis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece54b.

In addition, the unitary unit59b(FIG.11A) includes the resistor arms Ra and Rc which extend in parallel with each other toward the top right of the drawing and the resistor arms Rb and Rd which extend in parallel with each other toward the bottom right of the drawing, and includes an intersecting part59b0where the resistor arms Ra and Rc are arranged in a direction in which the resistor arms Ra and Rc intersect with the resistor arms Rb and Rd and where the resistor arms Ra and Rc alternately intersect with the resistor arms Rb and Rd upwardly/downwardly. An angle at which the resistor arms Ra and Rc intersect with the resistor arms Rb and Rd may be 90 degrees. In the intersecting part59b0, the electrode piece55ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece52d, the electrode piece54ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53b, the electrode piece54cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53d, and the electrode piece55cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece52b. As a result, the resistor arms Ra to Rd can be assembled on one surface in a four-braid pattern and disposed in a limited region.

Furthermore, outside the intersecting part59b0, such as a coupling part between the unitary units59aand59bor a coupling part between the unitary units59aand59band the terminals VDD, GND, NP1, and NP2, the electrode piece54ais arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53c, the electrode piece54bis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53d, the electrode piece54cis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53a, and the electrode piece54dis arranged to be upwardly/downwardly spaced apart from and intersect with the electrode piece53b.

It should be noted that the resistor arm Ra is arranged with a partial arm in the unitary unit59a(seeFIG.10A), which includes two electrode pieces53aand one electrode piece52abetween them, being oriented in the +X and −Y directions, and with a partial arm in the unitary unit59b(seeFIG.11A) connected to the partial arm in the unitary unit59a, the unitary unit59bwhich includes two electrode pieces54aand one electrode piece55abetween them, being oriented in the +X and +Y directions, in array sequence via the plurality of magneto resistive elements51a. Here, the electrode piece53a, the electrode piece52a, the electrode piece53a, the electrode piece54a, the electrode piece55a, and the electrode piece54awhich are successively linked via the magneto resistive elements51arespectively intersect with the electrode piece54c, the electrode piece55d, the electrode piece54b, the electrode piece53c, the electrode piece52d, and the electrode piece53b.

In addition, the resistor arm Rb is arranged with a partial arm in the unitary unit59a(seeFIG.10A), which includes two electrode pieces54band one electrode piece55bbetween them, being oriented in the +X and +Y directions, and with a partial arm in the unitary unit59b(see FIG.11A) connected to the partial arm in the unitary unit59a, the unitary unit59bwhich includes two electrode pieces53band one electrode piece52bbetween them, being oriented in the +X and −Y directions, in array sequence via the plurality of magneto resistive elements51b. Here, the electrode piece54b, the electrode piece55b, the electrode piece54b, the electrode piece53b, the electrode piece52b, and the electrode piece53bwhich are successively linked via the magneto resistive elements51brespectively intersect with the electrode piece53a, the electrode piece52c, the electrode piece53d, the electrode piece54a, the electrode piece55c, and the electrode piece54d.

In addition, the resistor arm Rc is arranged with a partial arm in the unitary unit59a(seeFIG.10A), which includes two electrode pieces53cand one electrode piece52cbetween them, being oriented in the +X and −Y directions, and with a partial arm in the unitary unit59b(seeFIG.11A) connected to the partial arm in the unitary unit59a, the unitary unit59bwhich includes two electrode pieces54cand one electrode piece55cbetween them, being oriented in the +X and +Y directions, in array sequence via the plurality of magneto resistive elements51c. Here, the electrode piece53c, the electrode piece52c, the electrode piece53c, the electrode piece54c, the electrode piece55c, and the electrode piece54cwhich are successively linked via the magneto resistive elements51crespectively intersect with the electrode piece54d, the electrode piece55b, the electrode piece54a, the electrode piece53d, the electrode piece52b, and the electrode piece53a.

In addition, the resistor arm Rd is arranged with a partial arm in the unitary unit59a(seeFIG.10A), which includes two electrode pieces54dand one electrode piece55dbetween them, being oriented in the +X and +Y directions, and with a partial arm in the unitary unit59b(seeFIG.11A) connected to the partial arm in the unitary unit59a, the unitary unit59bwhich includes two electrode pieces53dand one electrode piece52dbetween them, being oriented in the +X and −Y directions, in array sequence via the plurality of magneto resistive elements51d. Here, the electrode piece54d, the electrode piece55d, the electrode piece54d, the electrode piece53d, the electrode piece52d, and the electrode piece53dwhich are successively linked via the magneto resistive elements51drespectively intersect with the electrode piece53b, the electrode piece52a, the electrode piece53c, the electrode piece54b, the electrode piece55a, and the electrode piece54c.

Furthermore, lengths of the two electrode pieces53aincluded in the partial arm in the unitary unit59aof the resistor arm Ra and of the two electrode pieces54aincluded in the partial arm in the unitary unit59bare equal to each other. In addition, lengths of the two electrode pieces54bincluded in the partial arm in the unitary unit59aof the resistor arm Rb and of the two electrode pieces53bincluded in the partial arm in the unitary unit59bare equal to each other. Lengths of the two electrode pieces53cincluded in the partial arm in the unitary unit59aof the resistor arm Rc and of the two electrode pieces54cincluded in the partial arm in the unitary unit59bare equal to each other. In addition, lengths of the two electrode pieces54dincluded in the partial arm in the unitary unit59aof the resistor arm Rd and of the two electrode pieces53dincluded in the partial arm in the unitary unit59bare equal to each other. Lengths of these electrode pieces53a,54a,53b,54b,53c,54c,53d, and54dare equal to each other. It should be noted that the lengths of the electrode pieces are defined as lengths in directions in which two magneto resistive elements51ato51dthat are adjacent to each other are connected.

In addition, lengths of the one electrode pieces52aincluded in the partial arm in the unitary unit59aof the resistor arm Ra and of the one electrode pieces55aincluded in the partial arm in the unitary unit59bare equal to each other. In addition, lengths of the one electrode pieces55bincluded in the partial arm in the unitary unit59aof the resistor arm Rb and of the one electrode pieces52bincluded in the partial arm in the unitary unit59bare equal to each other. In addition, lengths of the one electrode pieces52cincluded in the partial arm in the unitary unit59aof the resistor arm Rc and of the one electrode pieces55cincluded in the partial arm in the unitary unit59bare equal to each other. In addition, lengths of the one electrode pieces55dincluded in the partial arm in the unitary unit59aof the resistor arm Rd and of the one electrode piece52dincluded in the partial arm in the unitary unit59bare equal to each other. Lengths of these electrode pieces52a,55a,52b,55b,52c,55c,52d, and55dare equal to each other. It should be noted that the lengths of the electrode pieces are defined as lengths in directions in which two magneto resistive elements51ato51dthat are adjacent to each other are connected.

The resistor arms Ra to Rd are arranged to be shifted in specific directions relative to each other. In both of the unitary units59aand59b, the resistor arm Rb is arranged to be shifted in the −X and +Y directions and shifted in the −X and −Y directions (in other words, shifted in the −X direction) with respect to the resistor arm Ra. The resistor arm Rc is arranged to be shifted in the +X and −Y directions and shifted in the +X and +Y directions (in other words, shifted in the +X direction) with respect to the resistor arm Ra. The resistor arms Rb and Rc are arrayed to be shifted in opposite directions with respect to the resistor arm Ra, so that they are arranged symmetrically with respect to a central axis L parallel to the X axis direction. The resistor arm Rd is arranged symmetrically with the resistor arm Ra with respect to the central axis L. As a result, when the resistor arms Ra to Rd are viewed from the X axis direction, the Y axis direction, the Z axis direction, or any direction, a pair of partial loops with equal loop areas and opposite polarities are formed.

It should be noted that the resistor arms Ra to Rd may include one or more unitary units59aand one or more unitary units59b, and may include one or more intersecting parts59a0and one or more intersecting parts59b0(in total, a plurality of intersecting parts59a0and59b0). In addition, they may include one or more partial arms of the resistor arms Ra, one or more partial arms of the resistor arms Rb, one or more partial arms of the resistor arms Rc, and one or more partial arms of the resistor arms Rd (in total, a plurality of respective partial arms of the resistor arms Ra to Rd) in the unitary unit59a, and may include one or more partial arms of the resistor arms Ra, one or more partial arms of the resistor arms Rb, one or more partial arms of the resistor arms Rc, and one or more partial arms of the resistor arms Rd (in total, a plurality of respective partial arms of the resistor arms Ra to Rd) in the unitary unit59b. In the present embodiment, two unitary units59aand a unitary unit59bcoupled therebetween are included, so that two intersecting parts59a0and one intersecting part59b0are included. Furthermore, an intersecting part similar to the intersecting parts59a0and59b0is included between the unitary units59aand59b.

Here, the intersecting part59a0includes a partial loop formed of eight electrode pieces52a,53a,54b,55b,52c,53c,54d, and55dwhen viewed in the Z axis direction, the intersecting part59b0includes a partial loop formed of eight electrode pieces54a,55a,52b,53b,54c,55c,52d, and53dwhen viewed in the Z axis direction, and coupling the unitary units59aand59bforms a partial loop formed of eight electrode pieces54a,55a,54b,55b,52c,53c,52d, and53dbetween the intersecting parts59a0and59b0. In other words, coupling the unitary units59aand59bforms one or more pairs of partial loops with equal loop areas and opposite polarities when viewed in the Z axis direction.

FIG.12Ashows a principle of suppressing a di/dt noise caused by application of an X direction magnetic field. As an example, a case is considered in which a magnetic flux (solid arrow) oriented in the +X direction is applied to resistor arms Ra to Rd in a unitary unit59a. When the magnetic flux is applied, induced electromotive forces directed leftward (open arrow), downward (filled arrow), leftward (open arrow), and downward (filled arrow) in the drawing are respectively generated in electrode pieces52aand53a, electrode pieces54band55b, electrode pieces52cand53c, and electrode pieces54dand55dwhich form partial loops on a central axis L (seeFIG.9) when viewed in the X direction. Here, lengths of the electrode pieces52aand53a, the electrode pieces54band55b, the electrode pieces52cand53c, and the electrode pieces54dand55d(that is, lengths of parts which form the partial loops) are equal. Furthermore, the electrode pieces52aand53aand the electrode pieces52cand53care connected via a power source terminal VDD, so that induced electromotive forces generated therein are canceled out. In addition, the electrode pieces54band55band the electrode pieces54dand55dare connected via a ground terminal GND, so that induced electromotive forces generated therein are canceled out.

It should be noted that, also when the X direction magnetic field is applied to other electrode pieces which form partial loops on the central axis L (seeFIG.9), induced electromotive forces are canceled out based on a similar principle.

FIG.12Bshows another principle of suppressing the di/dt noise caused by application of the X direction magnetic field. As an example, a case is considered in which a magnetic flux (dotted arrow) oriented in the +X direction is applied to the resistor arms Ra to Rd in the unitary unit59a. When the magnetic flux is applied, induced electromotive forces directed rightward (filled arrow), upward (open arrow), rightward (filled arrow), and upward (open arrow) in the drawing are respectively generated in the electrode pieces52aand53a, the electrode piece54b, the electrode piece53b, and the electrode pieces54dand55dwhich form partial loops on the −Y side of the central axis L (seeFIG.9) when viewed in the X direction. Here, lengths of the electrode pieces52aand53a, the electrode piece54b, the electrode piece53b, and the electrode pieces54dand55d(that is, lengths of parts which form the partial loops) are equal. Furthermore, the electrode pieces52aand53aand the electrode piece54bare connected via an output terminal Np1, so that induced electromotive forces generated therein are canceled out. In addition, the electrode piece53band the electrode pieces54dand55dare connected via the ground terminal GND, so that induced electromotive forces generated therein are canceled out.

It should be noted that, also when the X direction magnetic field is applied to other electrode pieces which form partial loops on the −Y side of the central axis L (seeFIG.9), induced electromotive forces are canceled out based on a similar principle. In addition, since the resistor arms Ra to Rd are formed symmetrically with respect to the central axis L, induced electromotive forces are canceled out based on a similar principle also in electrode pieces which form partial loops on the +Y side of the central axis L.

FIG.13Ashows a principle of suppressing a di/dt noise caused by application of a Y direction magnetic field. As an example, a case is considered in which magnetic fluxes (solid arrow and dotted arrow) oriented in the +Y direction are applied to resistor arms Ra to Rd in a unitary unit59a. When a magnetic flux (solid arrow) is applied, induced electromotive forces directed leftward (open arrow) and upward (filled arrow) in the drawing are respectively generated in an electrode piece52aand an electrode piece55dwhich form a partial loop on a central axis L (seeFIG.9) when viewed in the Y direction. When a magnetic flux (dotted arrow) is applied, induced electromotive forces directed leftward (open arrow) and upward (filled arrow) in the drawing are respectively generated in an electrode piece52cand an electrode piece55bwhich form a partial loop on the central axis L (seeFIG.9) when viewed in the Y direction. Here, lengths of the electrode piece52aand the electrode piece52c(that is, lengths of parts which form the partial loops) are equal and the electrode piece52aand the electrode piece52care connected via a power source terminal VDD, so that induced electromotive forces generated therein are canceled out. In addition, lengths of the electrode piece55band the electrode piece55d(that is, lengths of parts which form the partial loops) are equal and the electrode piece55band the electrode piece55dare connected via a ground terminal GND, so that induced electromotive forces generated therein are canceled out.

It should be noted that, also when the Y direction magnetic field is applied to other electrode pieces which form partial loops on the central axis L (seeFIG.9), induced electromotive forces are canceled out based on a similar principle.

FIG.13Bshows another principle of suppressing the di/dt noise caused by application of the Y direction magnetic field. As an example, a case is considered in which magnetic fluxes (solid arrow and dotted arrow) oriented in the +Y direction are applied to the resistor arms Ra to Rd in the unitary unit59a. When a magnetic flux (solid arrow) is applied, induced electromotive forces directed downward (open arrow) and rightward (filled arrow) in the drawing are respectively generated in an electrode piece54dand an electrode piece53bwhich form a partial loop on the −Y side of the central axis L (seeFIG.9) when viewed in the Y direction. When a magnetic flux (dotted arrow) is applied, induced electromotive forces directed downward (open arrow) and rightward (filled arrow) in the drawing are respectively generated in an electrode piece54band an electrode piece53awhich form an adjacent partial loop. Here, lengths of the electrode piece54band the electrode piece54d(that is, lengths of parts which form the partial loops) are equal and the electrode piece54band the electrode piece54dare connected via the ground terminal GND, so that induced electromotive forces generated therein are canceled out. In addition, lengths of the electrode piece53aand the electrode piece53b(that is, lengths of parts which form the partial loops) are equal and the electrode piece53aand the electrode piece53bare connected via an output terminal Np1, so that induced electromotive forces generated therein are canceled out.

It should be noted that, also when the Y direction magnetic field is applied to other electrode pieces which form partial loops on the −Y side of the central axis L (seeFIG.9), induced electromotive forces are canceled out based on a similar principle. In addition, since the resistor arms Ra to Rd are formed symmetrically with respect to the central axis L, induced electromotive forces are canceled out based on a similar principle also in electrode pieces which form partial loops on the +Y side of the central axis L.

FIG.14Ashows a principle of suppressing a di/dt noise caused by application of a Z direction magnetic field. As an example, a case is considered in which a magnetic flux (cross mark) oriented in the −Z direction is applied to resistor arms Ra to Rd in a unitary unit59a. When the magnetic flux is applied, induced electromotive forces directed downward to the right (open arrow), upward to the right (filled arrow), upward to the left (open arrow), and downward to the left (filled arrow) in the drawing are respectively generated in electrode pieces52aand53a, electrode pieces54band55b, electrode pieces52cand53c, and electrode pieces54dand55dwhich form partial loops on a central axis L (seeFIG.9) when viewed in the Z direction. Here, lengths of the electrode pieces52aand53a, the electrode pieces54band55b, the electrode pieces52cand53c, and the electrode pieces54dand55d(that is, lengths of parts which form the partial loops) are equal. Furthermore, the electrode pieces52aand53aand the electrode pieces54band55bare connected via an output terminal Np1, so that induced electromotive forces generated therein are canceled out. In addition, the electrode pieces52cand53cand the electrode pieces54dand55dare connected via an output terminal Np2, so that induced electromotive forces generated therein are canceled out.

It should be noted that, also when the Z direction magnetic field is applied to other electrode pieces which form partial loops on the central axis L (seeFIG.9), induced electromotive forces are canceled out based on a similar principle.

FIG.14Bshows another principle of suppressing of the di/dt noise caused by application of the Z direction magnetic field. As an example, a case is considered in which magnetic fluxes (cross marks on the left and right) oriented in the −Z direction are applied to the resistor arms Ra to Rd in the unitary unit59a. When a magnetic flux (cross mark on the left) is applied, induced electromotive forces directed upward to the left (open arrow), upward to the right (open arrow), downward to the right (open arrow), and downward to the left (open arrow) in the drawing are respectively generated in the electrode pieces52aand53a, the electrode piece54b, the electrode piece53b, and the electrode pieces54dand55dwhich form partial loops on the −Y side of the central axis L (seeFIG.9) when viewed in the Z direction. When a magnetic flux (cross mark on the right) is applied, induced electromotive forces directed upward to the left (filled arrow), upward to the right (filled arrow), downward to the right (filled arrow), and downward to the left (filled arrow) in the drawing are respectively generated in the electrode pieces52cand53c, the electrode piece54a, the electrode piece53a, and the electrode pieces54band55bwhich form an adjacent partial loop. Here, lengths of the electrode pieces52aand53a, the electrode piece54b, the electrode piece53b, the electrode pieces54dand55d, the electrode pieces52cand53c, the electrode piece54a, the electrode piece53a, and the electrode pieces54band55b(that is, lengths of parts which form the partial loops) are equal. Furthermore, the electrode pieces52cand53cand the electrode pieces54dand55dare connected via the output terminal Np2, so that induced electromotive forces generated therein are canceled out. In addition, the electrode pieces52aand53a, the electrode piece54a, the electrode piece53b, and the electrode pieces54band55bare connected via the output terminal Np1, so that induced electromotive forces generated therein are canceled out.

It should be noted that, also when the Z direction magnetic field is applied to other electrode pieces which form partial loops on the −Y side of the central axis L (seeFIG.9), induced electromotive forces are canceled out based on a similar principle. In addition, since the resistor arms Ra to Rd are formed symmetrically with respect to the central axis L, induced electromotive forces are canceled out based on a similar principle also in electrode pieces which form partial loops on the +Y side of the central axis L.

It should be noted that, in a unitary unit59bas well, di/dt noises caused by application of an X direction magnetic field, a Y direction magnetic field, and the Z direction magnetic field are suppressed similarly to the unitary unit59a.

As described above, the resistor arms Ra to Rd are connected in a Wheatstone bridge circuit pattern. One end of the resistor arm Ra (the end at the top right of the drawing) is connected to one end of the resistor arm Rb (the end at the top right of the drawing) to form the output terminal Np1, one end of the resistor arm Rc (the end at the top right of the drawing) is connected to one end of the resistor arm Rd (the end at the top right of the drawing) to form an output terminal Np2, another end of the resistor arm Ra (the end at the bottom left of the drawing) is connected to another end of the resistor arm Rc (the end at the bottom left of the drawing) to form a power source terminal VDD, and another end of the resistor arm Rb (the end at the bottom left of the drawing) is connected to another end of the resistor arm Rd (the end at the bottom left of the drawing) to form a ground terminal GND. Here, magnetic field detection directions of a magneto resistive element51aand a magneto resistive element51dare the same, magnetic field detection directions of a magneto resistive element51band a magneto resistive element51care the same, and the magnetic field detection directions of the magneto resistive element51aand the magneto resistive element51dare opposite to the magnetic field detection directions of the magneto resistive element51band the magneto resistive element51c.

When a magnetic field is applied to the magneto resistive elements51ato51dincluded in the resistor arms Ra to Rd of the magnetic sensor59, for example, when a magnetic field is applied in the same direction as the magnetic field detection directions of the magneto resistive element51aand the magneto resistive element51d(a direction opposite to the magnetic field detection directions of the magneto resistive element51band the magneto resistive element51c), resistance values of the resistor arm Ra and the resistor arm Rd respectively including the magneto resistive element51aand the magneto resistive element51ddecrease, and resistance values of the resistor arm Rb and the resistor arm Rc respectively including the magneto resistive element51band the magneto resistive element51cincrease, so that resistance balance between the resistor arms Ra to Rd is disrupted. Therefore, a magnetic field intensity can be detected by inputting a drive voltage to the power source terminal VDD with respect to the ground terminal GND and detecting a differential voltage outputted from between the output terminals Np1and Np2.

The magnetic sensor50according to the second embodiment includes: a first resistor arm Ra having: a plurality of first magneto resistive elements51awhich are arrayed on one surface; a first electrode piece52awhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of first magneto resistive elements51a; and a second electrode piece53awhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of first magneto resistive elements51a, where the plurality of first magneto resistive elements51aare alternately connected in array sequence by the first electrode piece52aand the second electrode piece53a; a second resistor arm Rb having: a plurality of second magneto resistive elements51barrayed on the one surface; a third electrode piece54bwhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of second magneto resistive elements51b; and a fourth electrode piece55bwhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of second magneto resistive elements51b, where the plurality of second magneto resistive elements51bare alternately connected in array sequence by the third electrode piece54band the fourth electrode piece55b; a third resistor arm Rc having: a plurality of third magneto resistive elements51carrayed on the one surface; a fifth electrode piece52cwhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of third magneto resistive elements51c; and a sixth electrode piece53cwhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of third magneto resistive elements51c, where the plurality of third magneto resistive elements51care alternately connected in array sequence by the fifth electrode piece52cand the sixth electrode piece53c; and a fourth resistor arm Rd having: a plurality of fourth magneto resistive elements51darrayed on the one surface; a seventh electrode piece54dwhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of fourth magneto resistive elements51d; and an eighth electrode piece55dwhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of fourth magneto resistive elements51d, where the plurality of fourth magneto resistive elements51dare alternately connected in array sequence by the seventh electrode piece54dand the eighth electrode piece55d, where the magnetic sensor50includes an intersecting part in which the first electrode piece52ais arranged to be upwardly/downwardly spaced apart from and intersect with the eighth electrode piece55d, the second electrode piece53ais arranged to be upwardly/downwardly spaced apart from and intersect with the third electrode piece54b, the fifth electrode piece52cis arranged to be upwardly/downwardly spaced apart from and intersect with the fourth electrode piece55b, and the sixth electrode piece53cis arranged to be upwardly/downwardly spaced apart from and intersect with the seventh electrode piece54d.

According to this, the first resistor arm Ra having the first magneto resistive elements51awhich are arrayed on one surface, the second resistor arm Rb having the second magneto resistive elements51bwhich are arrayed on the same one surface, the third resistor arm Rc having the third magneto resistive element51cwhich are arrayed on the same one surface, and the fourth resistor arm Rd having the fourth magneto resistive element51dwhich are arrayed on the same one surface are assembled in a four-braid pattern, with the first electrode piece52awhich connects upper surfaces of two first magneto resistive elements51athat are adjacent being upwardly/downwardly spaced apart from and intersect with the eighth electrode piece55dwhich connects lower surfaces of two fourth magneto resistive elements51dthat are adjacent, with the second electrode piece53awhich connects lower surfaces of two first magneto resistive elements51athat are adjacent being upwardly/downwardly spaced apart from and intersect with the third electrode piece54bwhich connects upper surfaces of two second magneto resistive elements51bthat are adjacent, with the fifth electrode piece52cwhich connects upper surfaces of two third magneto resistive elements51cthat are adjacent being upwardly/downwardly spaced apart from and intersect with the fourth electrode piece55bwhich connects lower surfaces of two second magneto resistive elements52dthat are adjacent, and with the sixth electrode piece53cwhich connects lower surfaces of two third magneto resistive elements51cthat are adjacent being upwardly/downwardly spaced apart from and intersect with the seventh electrode piece54dwhich connects upper surfaces of two fourth magneto resistive elements51dthat are adjacent, so that one or more pairs of partial loops with opposite polarities are formed in the resistor arms Ra to Rd, and it is possible to cancel out the noise caused by the induced electromotive force for a time when the magnetic field is applied. Furthermore, the resistor arms Ra to Rd having a plurality of partial loops having a small size with respect to their arm lengths can suppress a common-mode noise caused by a gradient of the magnetic field intensity in a length range of the resistor arms Ra to Rd.

The magnetic sensor50according to the second embodiment includes: a first resistor arm Ra having: a plurality of first magneto resistive elements51awhich are arrayed on one surface; a ninth electrode piece54awhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of first magneto resistive elements51a; and a tenth electrode piece55awhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of first magneto resistive elements51a, where the plurality of first magneto resistive elements51aare alternately connected in array sequence by the ninth electrode piece54aand the tenth electrode piece55a; a second resistor arm Rb having: a plurality of second magneto resistive elements51barrayed on the one surface; a eleventh electrode piece52bwhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of second magneto resistive elements51b; and a twelfth electrode piece53bwhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of second magneto resistive elements51b, where the plurality of second magneto resistive elements51bare alternately connected in array sequence by the eleventh electrode piece52band the twelfth electrode piece53b, a third resistor arm Rc having: a plurality of third magneto resistive elements51carrayed on the one surface; a thirteenth electrode piece54cwhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of third magneto resistive elements51c; and a fourteenth electrode piece55cwhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of third magneto resistive elements51c, where the plurality of third magneto resistive elements51care alternately connected in array sequence by the thirteenth electrode piece54cand the fourteenth electrode piece55c; and a fourth resistor arm Rd having: a plurality of fourth magneto resistive elements51darrayed on the one surface; a fifteenth electrode piece52dwhich connects respective upper surfaces of two elements that are adjacent to each other and that are of the plurality of fourth magneto resistive elements51d; and an sixteenth electrode piece53dwhich connects respective lower surfaces of two elements that are adjacent to each other and that are of the plurality of fourth magneto resistive elements51d, where the plurality of fourth magneto resistive elements51dare alternately connected in array sequence by the fifteenth electrode piece52dand the sixteenth electrode piece53d, where the magnetic sensor50includes an intersecting part in which the ninth electrode piece54ais arranged to be upwardly/downwardly spaced apart from and intersect with the sixteenth electrode piece53b, the tenth electrode piece55ais arranged to be upwardly/downwardly spaced apart from and intersect with the eleventh electrode piece52d, the thirteenth electrode piece54cis arranged to be upwardly/downwardly spaced apart from and intersect with the twelfth electrode piece53d, and the fourteenth electrode piece55cis arranged to be upwardly/downwardly spaced apart from and intersect with the fifteenth electrode piece52b.

According to this, the resistor arms Ra to Rd are assembled in a four-braid pattern, so that one or more pairs of partial loops with opposite polarities are formed in the resistor arms Ra to Rd, and it is possible to cancel out the noise caused by the induced electromotive force for a time when the magnetic field is applied. Furthermore, the resistor arms Ra to Rd having a plurality of partial loops having a small size with respect to their arm lengths can suppress a common-mode noise caused by a gradient of the magnetic field intensity in a length range of the resistor arms Ra to Rd.

The current detection device100according to the second embodiment includes: a conductor24through which a to-be-measured current flows; and the magnetic sensor59which is arranged on the conductor24or near the conductor24. As a result, it is possible to suppress the di/dt noise caused by the induced electromotive force and the common-mode noise caused by the gradient of the magnetic field intensity.

It should be noted that, in the magnetic sensor59according to the second embodiment, the resistor arm Ra, the resistor arm Rc, the resistor arm Rd, and the resistor arm Rb are successively arranged in the +X direction and assembled in a four-braid pattern, but an arrangement order of the resistor arm Ra, the resistor arm Rc, the resistor arm Rd, and the resistor arm Rb is not limited to this, and they may be arranged in any order.

Modified Example

FIG.15AandFIG.15Brespectively show an internal configuration of a current detection device110according to a modified example through a package9in a top view and a side view. Here,FIG.15Bshows a cross-sectional structure of the current detection device110with respect to a reference line inFIG.15A. It should be noted that the upward/downward direction inFIG.15Ais defined as the longitudinal direction, the rightward/leftward direction inFIG.15AandFIG.15Bis defined as the lateral direction, and the upward/downward direction inFIG.15Bis defined as the height direction. The current detection device110is a sensor which measures an amount of current by using a magnetic sensor60to detect a magnetic field generated around a conductor24as a result of a to-be-measured current flowing through the conductor24, and can suppress especially a di/dt noise due to an induced electromotive force and/or a differential amplification noise caused by spread of a magnetic field distribution. The current detection device110includes the package9, a plurality of device terminals17, the conductor24, and the magnetic sensor60.

The package9is a member which encapsulates therein and protects each portion constituting the current detection device110, except for the plurality of device terminals17and respective terminal portions of the conductor24. The package9can be formed of a material similar to that of the package9in the current detection device100according to the first embodiment.

The plurality of device terminals17are secondary conductors for outputting, to an external device, a detection result of the to-be-measured current outputted from the magnetic sensor60. In the present example, as one example, eight device terminals17are arrayed at regular intervals on a left side of the package9with their longitudinal sides being oriented in the lateral direction. The plurality of device terminals17are formed similarly to those in the current detection device100according to the first embodiment.

The conductor24is a primary conductor which forms a current path through which the to-be-measured current flows. The conductor24is formed similarly to that in the current detection device100according to the first embodiment, and its terminal portions24aand24eare arranged on a right side of the package9, and two legs included in a curved portion24care arranged at a center of the package9.

The magnetic sensor60is a sensor which detects a magnetic field generated by the to-be-measured current passed through the conductor24. As one example, the magnetic sensor60is configured to detect a longitudinal magnetic field (one example of a horizontal magnetic field) generated around the conductor24, and includes a substrate61and two sensor bodies62.

The substrate61is a plate-like member which supports the two sensor bodies62. The substrate61is formed of, for example, silicon (Si), and has a plurality of wiring lines (not shown) laid on its upper surface.

The two sensor bodies62are sensors which detect the magnetic field generated by the to-be-measured current passed through the conductor24. A sensor body62includes four resistor arms Ra to Rd which are connected in a Wheatstone bridge circuit pattern similarly to the magnetic sensor50according to the first embodiment or the magnetic sensor59according to the second embodiment by using magneto resistive elements51arrayed on the substrate61. The two sensor bodies62are arranged on the substrate61to be longitudinally spaced apart from each other, and their respective power source terminals VDD, ground terminals GND, and output terminals Np1and Np2are connected to a wiring line on the substrate61.

The magnetic sensor60is arranged on the curved portion24cof the conductor24. As a result, the two sensor bodies62are respectively arranged on the two legs of the curved portion24c, and the wiring line on the substrate61connected to the respective power source terminals VDD, ground terminals GND, and output terminals Np1and Np2is connected to the device terminals17through wire bonding. As a result, it is possible to apply a drive voltage to the two sensor bodies62via the device terminals17and to output their respective output voltages.

The current detection device110is manufactured by: pressing one piece of metal plate to form a pattern of the plurality of device terminals17and the conductor24; performing a step providing process on the pattern to form terminal portions17aon the plurality of device terminals17and the terminal portions24aand24eon the conductor24; arranging the magnetic sensor60on the curved portion24cof the conductor24; connecting the magnetic sensor60to the device terminals17through wire bonding; molding the pattern except for the frame as well as the terminal portions17aof the plurality of device terminals17and the terminal portions24aand24eof the conductor24coupled to the frame, to form the package9; and finally cutting off the frame exposed on the outside of the package9from the pattern.

While the present invention has been described by way of the embodiments, the technical scope of the present invention is not limited to the above-described embodiments. It is apparent to persons skilled in the art that various alterations or improvements can be made to the above-described embodiments. It is also apparent from the description of the claims that embodiments added with such alterations or improvements can be included in the technical scope of the present invention.

It should be noted that the operations, procedures, steps, stages, and the like of each processing performed by an apparatus, system, program, and method shown in the claims, specification, or drawings can be realized in any order as long as the order is not indicated by “prior to,” “before,” or the like and as long as the output from a previous processing is not used in a later processing. Even if the operation flow is described using phrases such as “first” or “next” for the sake of convenience in the claims, specification, or drawings, it does not necessarily mean that the process must be performed in this order.

EXPLANATION OF REFERENCES