JP2015190930A - current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, if the heat radiation performance of a magnetometric sensor and a signal processing device is poor, the temperature becomes significantly different between the magnetometric sensor and the signal processing device when heat is generated in a current path, etc., resulting in the accuracy of detecting a current becoming degraded.SOLUTION: A current sensor according to the present invention comprises a first and a second magnetometric sensor for detecting magnetism, a current path wired in a first circumferential direction around the first magnetometric sensor and wired in a second circumferential direction opposite the first circumferential direction around the second magnetometric sensor, and a signal processing device for processing output signals from the first and second magnetometric sensors, the first and second magnetometric sensors and the signal processing device being disposed on a metal plate.

Description

  The present invention relates to a current sensor.

A current sensor having a pair of magnetic sensors is known (see, for example, Patent Document 1). In the current sensor, the influence of the external magnetic field is reduced by canceling the external magnetic fields received by each of the pair of magnetic sensors.
Patent Document 1 Japanese Translation of PCT International Publication No. 2003-510612

  However, the above-described current sensor has a problem that heat dissipation is poor because two magnetic sensors are arranged on the substrate. In general, when the ambient temperature of a magnetic sensor changes, the output changes as the temperature changes even if the ambient magnetic flux is constant. Therefore, when the temperature around the magnetic sensor changes, there arises a problem that current detection accuracy is deteriorated. Even if a temperature correction circuit is inserted, if there is a temperature difference between the magnetic sensor and the temperature correction circuit, it is difficult to perform accurate correction and it is difficult to measure current with high accuracy.

  In the first aspect of the present invention, the first magnetic sensor and the second magnetic sensor for detecting magnetism are wired in the first circulation direction around the first magnetic sensor, and the first magnetic sensor is arranged around the second magnetic sensor. A current path wired in a second circulation direction opposite to the first circulation direction; and a signal processing device for processing an output signal from the first magnetic sensor and the second magnetic sensor; The sensor, the second magnetic sensor, and the signal processing device provide a current sensor disposed on the metal plate.

  The summary of the invention does not enumerate all the features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

FIG. 3 is an internal configuration diagram of the current sensor 10 in a plan view. 3 is a plan view of the current sensor 10. FIG. 3 is a side view of the current sensor 10. FIG. It is a longitudinal cross-sectional view along the IV-IV line of FIG. FIG. 4 is a plan view in each manufacturing process of the current sensor 10. FIG. 4 is a plan view in each manufacturing process of the current sensor 10. FIG. 6 is a partially enlarged plan view of the current sensor 110 in which the shapes of the notches 130 and 132 are changed. 4 is a partially enlarged plan view of a current sensor 210 in which the shapes of the tips of a first extending portion 240 and a second extending portion 242 are changed. FIG. FIG. 6 is a longitudinal sectional view for explaining an embodiment in which the magnetically sensitive portions of the magnetic sensors 18 and 20 are brought close to the surface including the current path 112.

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

  FIG. 1 is an internal configuration diagram of the current sensor 10 in a plan view. FIG. 2 is a plan view of the current sensor 10. FIG. 3 is a side view of the current sensor 10. The current sensor 10 has a configuration in which the signal processing device 24 and the magnetic sensors 18 and 20 are arranged on a metal plate, thereby improving heat dissipation, and the temperature difference between the signal processing device 24 and the magnetic sensors 18 and 20 is reduced. Reduced. Thereby, the measurement accuracy of the current Cr is improved. The plan view is a state viewed from the vertical direction of the widest surface of the current sensor 10.

  The current sensor 10 includes a current path 12, a main support plate 14, a sub support plate 16, a magnetic sensor 18, a magnetic sensor 20, a plurality of device terminals 22, a signal processing device 24, and a package 26. .

  The current path 12 is made of a conductor such as metal. The current path 12 is formed in a plate shape. The current path 12 is formed in a substantially rectangular shape in plan view. The longitudinal direction of the current path 12 is the direction in which the current Cr flows. The current path 12 is disposed across two opposing sides of the package 26 so as to cross the current sensor 10. The two sides are defined as a first side and a second side.

  Both ends of the current path 12 function as current terminals 13. The current terminal 13 is formed integrally with the current path 12 and connected thereto. One current terminal 13 protrudes from the first side of the package 26 and is exposed. The other current terminal 13 protrudes from the second side of the package 26 and is exposed. The current terminal 13 is bent downward by forming and extends to the lower surface of the package 26. Here, the current path 12 is disposed on the side opposite to the side on which the signal processing device 24 is provided when viewed from the center of the package 26. Therefore, the current terminal 13 is arranged on the first side and the second side on the side farther from the third side where the device terminals are arranged with respect to the center positions of the first side and the second side.

  A pair of notches 30 and 32 are formed at the center of the current path 12. The notch 30 is formed at a position different from the notch 32 in the longitudinal direction of the current path 12. One notch 30 is provided on the main support plate 14 side, and the main support plate 14 side is open. The magnetic sensor 18 is disposed inside the notch 30 as viewed from the direction perpendicular to the plane including the current path 12. The other notch 32 is provided on the sub support plate 16 side, and the sub support plate 16 side is open. Thus, the notch 30 and the notch 32 are open on opposite sides. The notch 30 and the notch 32 may be provided symmetrically with respect to each other in the current path 12. For example, the notch 30 and the notch 32 may be formed at point-symmetric positions with the center of gravity of the current path 12 as the center of rotation.

  The magnetic sensor 20 is disposed inside the notch 32 as viewed from the direction perpendicular to the plane including the current path 12. Accordingly, the current path 12 is wired in the first circulation direction around the magnetic sensor 18, and is wired in the second circulation direction opposite to the first circulation direction around the magnetic sensor 20. For example, as shown by a dotted line in FIG. 1, the circulation direction of the current Cr flowing around the notch 30 of the current path 12 is clockwise (an clockwise direction in FIG. 1), which is an example of the first circulation direction. The counterclockwise direction (counterclockwise direction in FIG. 1) is an example of the second circulation direction opposite to the circulation direction of the current Cr flowing around the notch 32 of the path 12.

  The main support plate 14 is an example of a metal plate and a first metal plate. The main support plate 14 is preferably composed of a metal plate having high thermal conductivity. The main support plate 14 includes a support portion 36, a pair of device terminal portions 38, and a first extending portion 40.

  The support portion 36 is disposed at a substantially central portion of the package 26 in plan view. The support part 36 is formed in a shape close to a square in plan view. The support portion 36 has a larger planar area than the signal processing device 24. The support part 36 is connected to the signal processing device 24 by wire bonding.

  The pair of device terminal portions 38 is an example of an external terminal. The outer end portions of the pair of device terminal portions 38 protrude from the support portion 36 to one side of the package 26 and are exposed. The one side is the third side. The pair of device terminal portions 38 are disposed on the opposite sides of the third side of the package 26 with the center of the third side interposed therebetween. As shown in FIG. 3, the outer end portion of the device terminal portion 38 is bent by forming and reaches the lower surface of the package 26. As a result, the pair of device terminal portions 38 are connected to the wiring of the substrate on which the current sensor 10 is mounted. For example, the pair of device terminal portions 38 are connected to the ground potential of the substrate on which the current sensor 10 is mounted. An inner end portion of the device terminal portion 38 is electrically connected to the signal processing device 24 via the support portion 36.

  The first extending portion 40 protrudes from the support portion 36 to the side opposite to the pair of device terminal portions 38. The first extending portion 40 extends to the inside of the first cutout portion 30. The tip of the first extending portion 40 has a larger planar area than the magnetic sensor 18.

  The sub support plate 16 is an example of a metal plate. The sub-support plate 16 is made of the same material as the main support plate 14. The main support plate 14 and the sub support plate 16 are preferably made of a material having as high a heat dissipation property as possible. A preferable material is, for example, copper. The sub-support plate 16 may be made of a material different from that of the main support plate 14, but preferably has the same thermal conductivity as the main support plate 14. The sub-support plate 16 is disposed on the opposite side of the main support plate 14 with the current path 12 interposed therebetween. The sub-support plate 16 is separated from the main support plate 14 and the current path 12 and is insulated.

  The sub-support plate 16 has a second extending portion 42 and a suspension pin portion 44. The second extending portion 42 is provided on one end side of the sub support plate 16 and extends to the inside of the second notch portion 32. The tip of the second extending portion 42 has a larger planar area than the magnetic sensor 20. The suspension pin portion 44 is provided on the other end side of the sub-support plate 16, and protrudes outside from one side of the package 26 and is exposed. The one side of the package 26 is set as the fourth side. In other words, the suspension pin portion 44 protrudes from the fourth side facing the third side from which the device terminal portion 38 protrudes. As shown in FIG. 3, the suspension pin portion 44 is bent downward. However, the suspension pin portion 44 has a length that does not reach the lower surface of the package 26. Thereby, the suspension pin part 44 is not connected to the wiring of the board | substrate with which the current sensor 10 is mounted.

  The magnetic sensor 18 is disposed at an end on the first extending portion 40 of the main support plate 14 that is partially exposed to the outside of the package 26. The magnetic sensor 18 is disposed inside the notch 30. The magnetic sensor 20 is disposed at the end on the second extending portion 42 of the sub-support plate 16, part of which is exposed to the outside of the package 26. The magnetic sensor 20 is disposed inside the notch 32. The magnetic sensor 20 is provided in the package 26 on the side opposite to the signal processing device 24 with respect to the current path 12.

  The magnetic sensors 18 and 20 may be fixed to the main support plate 14 or the sub support plate 16 with a bonding material such as a conductive paste. The magnetic sensors 18 and 20 may be die-bonded by the main support plate 14 or the sub support plate 16 and a die attach film. Further, the magnetic sensors 18 and 20 may be disposed on the main support plate 14 or the sub support plate 16 via an insulator such as an insulating paste. In this case, the magnetic sensors 18 and 20 can be insulated from the main support plate 14 or the sub support plate 16. If the magnetic sensors 18 and 20 are fixed using an insulating paste, even if the amount of paste protrudes greatly, there is little possibility that the insulation decreases with the current path. Further, it is preferable that the magnetic sensitive portions of the magnetic sensors 18 and 20 are located as close as possible to the center position of the plate thickness of the current path 12 in the direction perpendicular to the surface of the current path 12. The magnetic sensitive parts of the magnetic sensors 18 and 20 are formed on the upper surfaces of the magnetic sensors 18 and 20, for example. The magnetically sensitive portion is a portion or surface that detects magnetism in the magnetic sensors 18 and 20.

  The magnetic sensors 18 and 20 are individually connected to the signal processing device 24 by wire bonding. The magnetic sensors 18 and 20 detect surrounding magnetism. An example of the magnetic sensors 18 and 20 is a compound semiconductor Hall element made of InAs or GaAs, or a Hall element made of silicon. Other examples of the magnetic sensors 18 and 20 are a Hall IC or a magnetoresistive element in which a Hall element made of silicon and an amplifier circuit are integrated. [0] Another example of the magnetic sensors 18, 20 is a magnetoresistive element. An example of magnetism detected by the magnetic sensors 18 and 20 is magnetism generated by a current flowing through the current path 12. The magnetic sensors 18 and 20 output a voltage corresponding to the detected surrounding magnetism to the signal processing device 24 as an output signal.

  The plurality of device terminals 22 are disposed outside the main support plate 14. One end of the device terminal 22 extends to the main support plate 14. One end of the device terminal 22 is disposed away from the main support plate 14. The other end of the device terminal 22 protrudes from the third side of the package 26 and is exposed. The third side of the package 26 here is a side between the first side and the second side where the pair of current terminals 13 are arranged. If the third side is perpendicular to the first side and the second side, the size of the current sensor 10 as a whole is preferably reduced. The plurality of device terminals 22 are individually connected to the signal processing device 24 by wire bonding. Similar to the device terminal portion 38 shown in FIG. 3, the outer end portion of the device terminal 22 is bent by forming and reaches the lower surface of the package 26. The device terminal 22 is connected to a land arranged on a printed wiring board on which the current sensor 10 is mounted. For example, one of the plurality of device terminals 22 is connected to a ground potential wiring through a land. One of the plurality of device terminals 22 is connected to a power supply potential wiring through a land. One of the plurality of device terminals 22 is connected as an output terminal to a wiring of an external device via a land.

  The signal processing device 24 is disposed on the support portion 36 of the main support plate 14. In addition, the signal processing device 24 may be arrange | positioned through the main support plate 14 and an electrically conductive paste, and may be arrange | positioned through insulators, such as an insulating paste and a die attach film. The signal processing device 24 may include, for example, a storage unit such as an amplifier, a buffer, a bias unit, and an EEPROM, and a temperature correction circuit that corrects the temperature of output signals from the magnetic sensors 18 and 20. The signal processing device 24 processes output signals of the magnetic sensors 18 and 20. For example, the signal processing device 24 outputs a voltage corresponding to the current Cr flowing in the current path 12 based on the difference between the output signal of the magnetic sensor 18 and the output signal of the magnetic sensor 20. In the present embodiment, the magnetic sensors 18 and 20 and the signal processing device 24 have a hybrid configuration including independent chips, but may have other configurations.

  The package 26 is made of a resin having excellent insulating properties such as epoxy. The package 26 covers the current path 12, the main support plate 14, the sub support plate 16, the magnetic sensors 18 and 20, the plurality of device terminals 22, and the signal processing device 24. Note that the package 26 covers an arrangement portion where the magnetic sensors 18 and 20 and the signal processing device 24 are arranged on the main support plate 14 and the sub support plate 16. The package 26 may mold an arrangement portion on the main support plate 14 and the sub support plate 16 in which the current path 12, the magnetic sensors 18 and 20, and the signal processing device 24 are arranged. The package 26 does not cover the both ends of the current path 12, the end of the device terminal 22 on the main support plate 14 side, the end of the device terminal 38, and the end of the sub-support plate 16. Note that a low stress resin having a Young's modulus smaller than that of the mold resin of the package 26 may be applied to the magnetic sensors 18 and 20 between the package 26.

  Next, the operation of the current sensor 10 described above will be described. 4 is a longitudinal sectional view taken along line IV-IV in FIG.

  The current Cr to be measured flows through the current path 12 along the direction indicated by the dotted line in FIG. When the current Cr flows around the notch 30, the current Cr flows clockwise in a plan view. On the other hand, when the current Cr flows around the notch 32, the current Cr flows counterclockwise in plan view. Therefore, the magnetic flux density Bas generated by the current Cr flowing through the cutout portion 30 and the magnetic flux density Bab generated by the current Cr flowing through the cutout portion 32 have substantially the same magnitude and are in opposite directions. Thereby, the magnetic sensor 18 and the magnetic sensor 20 detect the magnetic flux densities Bas and Bbs due to the current Cr in the opposite directions. Here, since the magnetic sensors 18 and 20 are arranged at close positions adjacent to each other, it is assumed that external magnetic noises Ban and Bbn having the same magnitude in the same direction are detected.

In this case, the output signal Va of the magnetic sensor 18 and the output signal Vb of the voltage of the magnetic sensor 20 are respectively expressed by the following equations.
Va = Ka × (Bas + Ban) + Vaoff
Vb = Kb × (−Bbs + Bbn) + Vboff
Ka, Kb: Sensitivity of the magnetic sensors 18, 20.
Vaoff, Vboff: The offset of each magnetic sensor 18, 20.
Here, assuming that the magnetic sensors 18 and 20 have the same characteristics, the offsets Vaoff and Vboff are approximated to be equal to each other. Further, the external magnetic noises Ban and Bbn detected by the magnetic sensors 18 and 20 are approximated to be equal to each other because both positions are close to each other.

In general, the sensitivity of a magnetic sensor varies with temperature.
Since the magnetic sensors 18 and 20 are disposed on the main support plate 14 and the sub support plate 16 which are metal plates, respectively, the temperatures are substantially the same. Therefore, the sensitivities Ka and Kb are substantially equal to each other, and K = Ka = Kb.

The signal processing device 24 acquires the output signals Va and Vb from the magnetic sensors 18 and 20. The signal processing device 24 outputs the difference between the output signals Va and Vb. The output Vout of the signal processing device 24 is as follows.
Vout = Va−Vb = K × (Bas + Bbs)
From this equation, it can be seen that the influence of the external magnetic noises Ban and Bbn is canceled. Furthermore, since the signal processing device 24 and the magnetic sensors 18 and 20 are disposed on the metal main support plate 14 or the sub-support plate 16, the signal processing device 24 and the magnetic sensors 18 and 20 are The temperatures are substantially the same. Thereby, the temperature correction circuit of the signal processing device 24 can correct the influence of the sensitivity K of the magnetic sensors 18 and 20 with high accuracy, and the output changes of the magnetic sensor 18 and the magnetic sensor 20 due to the ambient temperature change can be corrected. Correction can be made with high accuracy. Assuming that the current Cr flowing through the current path 12 is substantially equal and the relationship between the magnetic flux densities generated by the current Cr is Bas≈Bbs, Vout is approximately twice Va or Vb. That is, it can be seen that the output is approximately twice that of a single magnetic sensor. The current sensor 10 measures a current based on Vout.

  As described above, in the current sensor 10, since the signal processing device 24 and the magnetic sensors 18 and 20 are disposed on the metal main support plate 14 or the sub support plate 16 having high heat dissipation, signal processing is performed. The heat dissipation of the device 24 and the magnetic sensors 18 and 20 can be improved. The temperature rises due to the current flowing through the current path 12, and the temperature rises much more in the place near the current path 12. In the current sensor 10, the temperature of the magnetic sensors 18, 20 and the signal processing device 24 are disposed on the first extending portion 40 and the second extending portion 42 made of a metal plate having high heat dissipation, so that current flows through the current path 12. Even if the temperature rises by this, the temperature difference becomes small. As a result, the current sensor 10 can accurately detect the magnetic field even when a large current is passed through the current path 12 and the temperature rises greatly. Furthermore, since the end portions of the main support plate 14 and the sub support plate 16 are exposed from the package 26, the current sensor 10 has a configuration in which heat dissipation is further improved, whereby the temperature of the magnetic sensors 18, 20 is increased. And the temperature difference between the signal processing device 24 can be reduced.

  In the current sensor 10, since the notches 30 and 32 are arranged at positions symmetrical with respect to each other, the magnetic flux density received by the magnetic sensors 18 and 20 is made substantially equal, and the temperature around the magnetic sensors 18 and 20 is set. Can be approximately equal. Furthermore, since the positions of the magnetic sensors 18 and 20 arranged inside the notches 30 and 32 are point-symmetric, the influence of heat due to the current flowing through the current path 12 is substantially equal in the magnetic sensors 18 and 20. Therefore, the magnetic sensors 18 and 20 can further reduce the influence due to the temperature difference between them.

  Next, a method for manufacturing the above-described current sensor 10 will be described. 5 and 6 are plan views of the current sensor 10 in each manufacturing process.

  As shown in FIG. 5, a metal plate 50 having a pattern is formed by piercing a part from one metal plate. In FIG. 5, the dot-hatched area is a portion that is punched from the metal plate 50. In this state, the current path 12, the main support plate 14, and the sub support plate 16 are connected to each other at the outer peripheral portion of the metal plate 50.

  Next, as shown in FIG. 6, a step is formed in the current path 12, the device terminal 22, and the device terminal portion 38 by forming the metal plate 50 by press working or the like. Next, the signal processing device 24 is die-bonded at a predetermined position on the main support plate 14, and the magnetic sensors 18 and 20 are disposed on the main support plate 14 and the sub support plate 16. The signal processing device 24, the magnetic sensors 18, 20, the device terminal 22, and the device terminal portion 38 are connected to each other by wire bonding.

  Next, as shown in FIGS. 2 and 3, the signal processing device 24, the magnetic sensors 18 and 20, the current path 12, the main support plate 14, and the sub support plate 16 are molded by a package 26 containing a resin material. . Further, the ends of the current path 12, the sub-support plate 16, the device terminal 22, and the device terminal portion 38 are cut and separated from each other. Thereby, the current sensor 10 is completed.

  Next, the form which changed a part of embodiment mentioned above is demonstrated.

  FIG. 7 is a partially enlarged plan view of the current sensor 110 in which the shapes of the notches 130 and 132 are changed. In the current sensor 110, the cutout portions 130 and 132 formed in the current path 112 have arc portions 160 and 162, respectively. The arc portions 160 and 162 have a shape in which the current path 112 is cut into an arc. Here, the arc portions 160 and 162 are semicircles as an example. Furthermore, when the arc portion 160 is a semicircle, it is preferable that the center of the semicircle coincides with the center of gravity of the magnetic sensor 18. Similarly, it is preferable that the center of the arc portion 162 coincides with the center of gravity of the magnetic sensor 20.

  Thus, by forming the arc portions 160 and 162 in the notches 130 and 132, the distance between the magnetic sensors 18 and 20 and the current path 112 can be reduced. This improves the sensitivity of the magnetic sensors 18 and 20 and increases the output signal. As a result, the detection accuracy of the current sensor 110 is further improved.

  FIG. 8 is a partially enlarged plan view of the current sensor 210 in which the shapes of the tips of the first extending portion 240 and the second extending portion 242 are changed. In the current sensor 210, the main support plate 214 on which the magnetic sensor 18 is disposed has a first extending portion 240 and a first end portion 264, and the sub-support plate 216 on which the magnetic sensor 20 is disposed is disposed on the second extending portion 242 and It has a second end 266.

  The first extending portion 240 extends inward of the notch portion 130 when viewed from the direction perpendicular to the surface including the current path 112. The first end portion 264 is provided on the distal end side of the first extending portion 240. The first end portion 264 has a width wider than the width of the first extending portion 240. The width here refers to the length in the direction intersecting with the extending direction of the first extending portion 240, for example, the direction orthogonal thereto. The first end 264 may be a partial circle. In this case, it is preferable that the center position of the first end portion 264 coincides with the arc portion 160 and the center position. A part of the first extending portion 240 is bent to form a stepped portion 241 so that the height of the magnetically sensitive surface of the magnetic sensor 18 is the same as or close to the height of the center of the plate thickness of the current path 112. Good. For example, the magnetic sensitive surface of the magnetic sensor 18 is formed on the upper surface.

  The second extending portion 242 extends inward of the notch portion 132 when viewed from the direction perpendicular to the plane including the current path 112. The second end 266 is provided on the distal end side of the second extending portion 242. The second end 266 has a width wider than the second extending portion 242. The width here refers to the length in the direction intersecting with the extending direction of the second extending portion 242, for example, in the orthogonal direction. The second end 266 may have a partial circular shape. In this case, it is preferable that the center position of the second end portion 266 matches the center position of the arc portion 162. A part of the second extending portion 242 is bent to form a stepped portion 243 so that the height of the magnetic sensitive surface of the magnetic sensor 20 is the same as or close to the height of the center of the plate thickness of the current path 112. Good. For example, the magnetic sensitive surface of the magnetic sensor 20 is formed on the upper surface.

  In the current sensor 210, the first end 264 and the second end 266 may be formed in a circular shape by crushing the main support plate 214 and the sub support plate 216 by a step processing such as coining.

  FIG. 9 is a longitudinal sectional view for explaining an embodiment in which the magnetically sensitive portions of the magnetic sensors 18 and 20 are brought close to the surface including the current path 112. FIG. 9 is a view corresponding to the longitudinal sectional view of FIG. In the example of FIG. 9, the magnetically sensitive portion is formed as a magnetically sensitive surface on the upper surface of the magnetic sensors 18 and 20. For example, the magnetic sensitive surfaces of the magnetic sensors 18 and 20 may be provided between the upper surface and the lower surface of the current path 112. The first extending portion 240 and the second extending portion 242 are stepped such as by bending or half-cutting to form the step portions 241 and 243, whereby the height of the magnetic sensitive surfaces of the magnetic sensors 18 and 20 is set to the current path 112. The height may be the same as or close to the height of the center of the plate thickness. In another example, the height of the magnetic sensitive surface of the magnetic sensors 18 and 20 is the same as or close to the height of the center of the plate thickness of the current path 112 by processing the current path 112 by steps such as bending or half blanking. It may be.

  Numerical values such as the shape, arrangement, material, and number of each component in the above-described embodiments may be changed as appropriate. Moreover, you may combine each embodiment suitably.

  For example, in the embodiment shown in FIG. 1, the height of the magnetic sensitive surfaces of the magnetic sensors 18 and 20 may be provided between the upper surface and the lower surface of the current path 12. Further, the height of the magnetic sensitive surfaces of the magnetic sensors 18 and 20 may be close to the surface including the current path 12. The magnetically sensitive surfaces of the magnetic sensors 18 and 20 may be brought closer to the surface including the current path 12 by processing the first extending portion 40 and the second extending portion 42 by steps such as bending or half blanking. In another example, the current-sensitive surfaces of the magnetic sensors 18 and 20 may be brought closer to the surface including the current path 12 by processing the current path 12 by a step such as bending or half blanking.

  Further, the suspension pin portion 44 may have a device terminal shape. As described above, when the suspension pin portion 44 is formed in the device terminal shape, heat can be released to the substrate, so that heat dissipation can be further improved.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

  DESCRIPTION OF SYMBOLS 10 Current sensor, 12 Current path, 13 Current terminal, 14 Main support plate, 16 Sub support plate, 18 Magnetic sensor, 20 Magnetic sensor, 22 Device terminal, 24 Signal processing device, 26 Package, 30 Notch, 32 Notch, 36 support part, 38 device terminal part, 40 first extension part, 42 second extension part, 44 pin part, 50 metal plate, 110 current sensor, 112 current path, 130 notch part, 132 notch part, 160 arc part, 162 Arc part, 210 Current sensor, 214 Main support plate, 216 Sub support plate, 240 First extension part, 241 step part, 242 Second extension part, 243 stage , 264 first end 266 second end

Claims (20)

A first magnetic sensor and a second magnetic sensor for detecting magnetism;
A current path wired around the first magnetic sensor in a first round direction, and around the second magnetic sensor in a second round direction opposite to the first round direction;
A signal processing device for processing output signals from the first magnetic sensor and the second magnetic sensor;
With
The first magnetic sensor, the second magnetic sensor, and the signal processing device are arranged on a metal plate.   Arrangement of the first magnetic sensor, the second magnetic sensor, the current path, and the signal processing device, and the first magnetic sensor, the second magnetic sensor, and the signal processing device on the metal plate. The current sensor according to claim 1, further comprising a package covering the portion.   3. The current sensor according to claim 2, wherein the package molds the arrangement portion of the first magnetic sensor, the second magnetic sensor, the current path, the signal processing device, and the metal plate.   The current sensor according to claim 3, wherein a low-stress resin having a Young's modulus smaller than that of a mold resin is applied to the first magnetic sensor and the second magnetic sensor. The first magnetic sensor is disposed on the first metal plate, a part of which is exposed outside the package,
5. The current sensor according to claim 2, wherein the second magnetic sensor is disposed on the second metal plate that is partially exposed outside the package. 6.   The current sensor according to claim 5, wherein the signal processing device is disposed on the first metal plate.   6. At least one of the first metal plate and the second metal plate has an external terminal exposed to the outside of the package and connected to a land of a printed wiring board on which the current sensor is mounted. 6. The current sensor according to 6.   6. At least one of the first metal plate and the second metal plate has a suspension pin that is exposed to the outside of the package and is not connected to a land of a printed wiring board on which the current sensor is mounted. The current sensor according to claim 7.   The current sensor according to claim 2, wherein the first magnetic sensor and the second magnetic sensor are connected to the signal processing device by wire bonding. The current path includes a first notch provided on the side of the metal plate where the first magnetic sensor is disposed, and a second notch provided on the side of the metal plate where the second magnetic sensor is disposed. And
The first magnetic sensor is provided on the inner side of the first notch as viewed from a direction perpendicular to a surface including the current path,
The current sensor according to any one of claims 1 to 9, wherein the second magnetic sensor is provided inside the second notch portion when viewed from a direction perpendicular to a surface including the current path.   The current sensor according to claim 10, wherein the first notch and the second notch are provided symmetrically with respect to each other in the current path.   The current sensor according to claim 10 or 11, wherein the first cutout portion and the second cutout portion have a shape in which the current path is cut out by an arc. The metal plate on which the first magnetic sensor is disposed has a first extending portion extending inward of the first notch portion as viewed from a direction perpendicular to a surface including the current path, and a width with respect to the extending direction. A first end that is wider than the first extending portion;
The metal plate on which the second magnetic sensor is disposed has a second extending portion extending inward of the second notch portion as viewed from a direction perpendicular to the surface including the current path, and a width with respect to the extending direction. The current sensor according to any one of claims 10 to 12, further comprising a second end portion that is wider than the second extending portion.   14. The current sensor according to claim 13, wherein the first extending portion and the second extending portion are stepped to bring a magnetically sensitive portion of the first magnetic sensor and the second magnetic sensor closer to a surface including the current path.   The current sensor according to any one of claims 1 to 14, wherein the current path is stepped to bring a surface including the current path closer to a magnetically sensitive portion of the first magnetic sensor and the second magnetic sensor.   16. The first magnetic sensor and the second magnetic sensor according to claim 1, wherein the magnetically sensitive portion is provided between the upper surface and the lower surface of the current path in a direction perpendicular to the surface including the current path. The current sensor described in 1.   The current sensor according to claim 1, wherein the first magnetic sensor and the second magnetic sensor are die-bonded to the metal plate by a die attach film. A first current terminal provided on a first side of the package and connected to the current path; and a second current terminal provided on a second side opposite to the first side and connected to the current path. ,
The first current terminal and the second current terminal are connected to the first side and the second side from the third side where the device terminal is arranged with respect to the center position of the first side and the second side. The current sensor according to claim 2, wherein the current sensor is disposed on a far side.   The current sensor according to claim 18, further comprising a plurality of device terminals connected to the signal processing device on a third side between the first side and the second side of the package.   The current sensor according to any one of claims 1 to 19, wherein the signal processing device includes a temperature correction circuit that corrects a temperature of output signals from the first magnetic sensor and the second magnetic sensor.

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