Sensor device and associated manufacturing method

Abstract

The invention relates to a sensor device and an associated manufacturing method. The sensor device comprises a current conductor designed to conduct a current; a differential magnetic field sensor chip arranged in the opening of the current conductor and designed to detect a magnetic field generated by the current; and a metal plate disposed over the current conductor and the magnetic field sensor chip.

Description

Technical Field

[0001] The present invention relates to a sensor device and a method for manufacturing the sensor device. Background Technology

[0002] Magnetic field sensors can be used to measure the intensity of current flowing through a conductor. For this, the strength of the magnetic field induced by the current at the location of the sensor should be sufficiently large. One possibility for achieving this is, for example, reducing the cross-sectional area of ​​the current conductor at the sensor's location. However, reducing the conductor's cross-sectional area may lead to increased power losses in the magnetic field sensor.

[0003] Manufacturers and developers of sensor devices are constantly striving to improve their products. Of particular interest may be increasing the measurement accuracy of sensor devices without necessarily increasing power consumption. Furthermore, it may be of interest to provide suitable methods for manufacturing such sensor devices. Summary of the Invention

[0004] Various aspects relate to a sensor device. The sensor device includes a current conductor designed to guide current. The sensor device also includes a differential magnetic field sensor chip disposed within an opening in the current conductor and designed to detect a magnetic field generated by the current. The sensor device also includes a metal plate disposed above the current conductor and above the magnetic field sensor chip.

[0005] Various aspects relate to a method for manufacturing a sensor device. The method includes arranging a current conductor designed to conduct current. The method also includes arranging a metal plate above the current conductor. Furthermore, the method includes arranging a differential magnetic field sensor chip in an opening in the current conductor below the metal plate, wherein the magnetic field sensor chip is designed to detect a magnetic field generated by the current.

[0006] Further features and advantages of the invention will be apparent to those skilled in the art upon reading the following detailed description and reviewing the accompanying drawings. Attached Figure Description

[0007] This invention is illustrative and is not limited in its representation in the accompanying drawings, in which the same reference numerals may refer to similar or identical elements. Elements in the drawings are not necessarily shown to scale. Features of different illustrated examples may be combined unless they are mutually exclusive.

[0008] Figure 1 contains Figure 1A and Figure 1B These figures show cross-sectional views or bottom views of the side of the sensor device 100 according to the present invention.

[0009] Figure 2 includes Figure 2A and Figure 2BThese figures illustrate the correlation between the magnetic field strength or the phase error of the magnetic field strength and the frequency of the measured current in the case of the sensor device according to the invention and in the case of a conventional sensor device.

[0010] Figure 3 A flowchart of a method for manufacturing a sensor device according to the present invention is shown. Detailed Implementation

[0011] Figure 1A and Figure 1B A cross-sectional view or bottom view of the side of the sensor device 100 according to the present invention is shown. It should be noted that, for the purpose of illustration, [the following text is missing]. Figure 1B Not all the components of the sensor device 100 described below are shown in the bottom view.

[0012] The sensor device 100 may include a current conductor 2, a differential magnetic field sensor chip 4 disposed in an opening 6 in the conductor 2, and a metal plate 8 disposed above the current conductor 2 and above the magnetic field sensor chip 4. In the example shown, the current conductor 2 may extend in the x-direction around the opening 6. The current conductor 2 may be designed to guide current, thereby generating or inducing a magnetic field 10, the field lines of which may extend around the current conductor 2. The magnetic field sensor chip 4 may be designed to detect the magnetic field 10 generated by the current.

[0013] The differential magnetic field sensor chip 4 can be an integrated circuit or a semiconductor chip, and thus can also be referred to as a differential magnetic field sensor IC. The differential magnetic field sensor chip 4 can have a first sensor element 12A and a second sensor element 12B. In the example shown, the two sensor elements 12A and 12B can be spaced apart from each other in the z-direction, that is, these sensor elements can be arranged on a (straight) line extending along the z-direction. The two sensor elements 12A and 12B can be sensitive in the y-direction, that is, designed to detect the y-component of the magnetic field 10 induced by the current at the location of the respective sensor element. Of course, one or both of the sensor elements 12A and 12B can also be sensitive with respect to other spatial directions, such as the x and / or z directions. Each of the two sensor elements 12A and 12B can generate a signal corresponding to the respective detected magnetic field component. By forming the difference or sum of the two signals (or the two detected magnetic field components), the current guided through the current conductor 2 can be determined. Therefore, the magnetic field sensor chip 4 can also be referred to as a current sensor or a current sensor chip.

[0014] The differential magnetic field sensor chip 4 or its sensor elements 12A and 12B are not limited to a specific sensor technology. In one example, sensor elements 12A and 12B may correspond to Hall sensor elements. In another example, sensor elements 12A and 12B may be magnetoresistive xMR sensor elements, particularly AMR, GMR, or TMR sensor elements. For example, each sensor element 12A and 12B may be implemented individually as a resistor bridge with, for example, four resistors. In one example, the resistors may be arranged in the form of a Wheatstone bridge. Sensor elements 12A and 12B may be integrated into the switching circuit of the magnetic field sensor chip 4. Signal amplification, analog-to-digital conversion, digital signal processing, and / or offset and temperature compensation may also be implemented in such circuitry. Components for signal amplification and / or analog-to-digital conversion, in addition to the components of the respective sensor elements, may or may not be considered part of sensor elements 12A and 12B.

[0015] The current conductor 2, also referred to as a conductive rail, is made of, for example, at least one of copper, aluminum, or their alloys. The current conductor 2 may have a (particularly constant) dimension 'a' around the opening 6 in the y-direction, which in a non-limiting example may be in the range of approximately 12 mm to approximately 20 mm (e.g., approximately 16 mm). The current conductor 2 may have a dimension 'b' in the z-direction, which in a non-limiting example may be in the range of approximately 1 mm to approximately 2.5 mm (e.g., approximately 1.5 mm). Figure 1B In the bottom view, the opening 6 of the current conductor 2 can have a substantially rectangular shape. In other examples, the opening 6 can have different shapes, such as annular, circular, oval, elliptical, square, or similar shapes. Figure 1B As can be seen from the bottom view, the sensor elements 12A and 12B of the magnetic field sensor chip 4 can be arranged offset relative to the center of the opening 6. Here, the offset c can be in the range of about 0.5 mm to about 1.5 mm (for example, about 1 mm).

[0016] The metal plate 8 may also be referred to as a metal sheet, metal plate, fluid plate, or flow plate, and is made of at least one of copper, aluminum, or alloys thereof. For example, the metal plate 8 can be manufactured by a stamping process. The metal plate 8 may have a dimension d in the x-direction, which in a non-limiting example is in the range of approximately 12 mm to approximately 20 mm (e.g., approximately 16 mm). The metal plate 8 may have a dimension e in the y-direction, which in a non-limiting example is in the range of approximately 15 mm to approximately 25 mm (e.g., approximately 20 mm). The dimension e of the metal plate 8 in the y-direction may be greater than the dimension a of the current conductor 2 in the y-direction. Furthermore, the dimension e of the metal plate 8 in the y-direction may be greater than the dimension d of the metal plate 8 in the x-direction. The metal plate 8 may have a dimension f in the z-direction, which in a non-limiting example is in the range of approximately 0.5 mm to approximately 1.5 mm (e.g., approximately 1 mm). The distance g from the upper side of the conductive rail 2 to the lower side of the metal plate 8 may in a non-limiting example be in the range of approximately 2.5 mm to approximately 5 mm (e.g., approximately 2.5 mm).

[0017] exist Figure 1B In the exemplary bottom view, the metal plate 8 may have a rectangular shape. In other examples, the metal plate 8 may have different shapes, such as annular, circular, oval, elliptical, square, or similar shapes. In the example, the corners of the metal plate 8 may be substantially pointed. In another example, the corners of the metal plate 8 may also be rounded. In the bottom view shown, the metal plate 8 may in particular be closed and without openings. Figure 1A As can be seen from the side view, the metal plate 8 can extend parallel to the current conductor 2. In the example shown, the metal plate 8 can be constructed substantially flat and extends substantially in the xy plane. However, in other examples, the metal plate 8 does not necessarily need to be constructed flat, but can, for example, be bent at least partially toward the direction of the current conductor 2.

[0018] The metal plate 8 can be designed to influence or alter the magnetic field 10 generated by the measuring current. In this case, it should be noted that, for simplicity, in... Figure 1AThe influence of the metal plate 8 on the magnetic field 10 is not considered or shown in the field lines of the magnetic field 10. The influence of the metal plate 8 on the magnetic field 10 can decrease with the distance from the metal plate 8. Because the first sensor element 12A can be arranged closer to the metal plate 8 than the second sensor element 12B, the influence of the metal plate 8 on measuring the first sensor element 12A may be greater than its influence on measuring the second sensor element 12B. When the distance between the second sensor element 12B and the metal plate 8 is sufficiently large, the influence of the metal plate 8 on measuring the second sensor element 12B can even be negligible. Therefore, a certain asymmetry in the measurement or measurement results of the two sensor elements 12A and 12B can be provided by the metal plate 8. As a result, the phase error of the measured magnetic field strength can be reduced, as subsequently combined with Figure 2A and 2B As discussed.

[0019] The sensor device 100 may also have additional components. In the example shown, the current conductor 2 and the metal plate 8 can be encapsulated in a first encapsulation material 14. Here, the magnetic field sensor chip 4 can be disposed outside the first encapsulation material 14. The magnetic field sensor chip 4 can be encapsulated in a second encapsulation material 16, wherein the current conductor 2 and the metal plate 8 can be disposed outside the second encapsulation material 16. Therefore, in this case, the current conductor 2 can be an external current conductor disposed outside the housing, which is formed by the second encapsulation material 16. Alternatively, in another example, in contrast to the example shown, the metal plate 8, the current conductor 2, and the magnetic field sensor chip 4 can be encapsulated in a common encapsulation material.

[0020] In a non-limiting example, one or both of the encapsulation materials 14 and 16 may be epoxy resin, which can be manufactured by a suitable molding process. Encapsulation materials 14 and 16 may be the same or different from each other. The first encapsulation material 14 may have a recess 18 in which the magnetic field sensor chip 4 or the second encapsulation material 16 and the magnetic field sensor chip 4 encapsulated therein may be arranged. The distance h from the upper side of the second encapsulation material 16 to the lower side of the metal plate 8 may be in the range of about 0.1 mm to about 2.6 mm (e.g., about 2.5 mm) in a non-limiting example.

[0021] In the example shown, the magnetic field sensor chip 4 can be mounted on a first circuit board (or first PCB) 20. Here, the circuit board 20 can extend perpendicularly to the current conductor 2. The first circuit board 20 can also be encapsulated in a second encapsulation material 16. The housing formed by the second encapsulation material 16 can be arranged on a second circuit board 22, which can be, for example, a gate driver PCB. The magnetic field sensor chip 4 can be electrically connected to the second circuit board 22 via the first circuit board 20 and pins 24. Mounting elements 26 can be arranged between the lower side of the first encapsulation material 14 and the upper side of the second circuit board 22; these mounting elements can also act as spacers.

[0022] As described above, the intensity By of the y-component of the magnetic field 10 can be detected or measured by the magnetic field sensor chip 4. In this case, Figure 2A The correlation between the magnetic field strength By and the frequency of the current guided through the current conductor 2 is shown in a first case of the sensor device with metal plate 8 according to the invention and in a second case of a conventional sensor device without metal plate. Here, the magnetic field strength By is plotted as a percentage (with respect to the output value at 0 Hz) relative to the frequency in Hz. Figure 2B The correlation between the phase (in degrees) of the magnetic field strength By and the frequency (in Hz) of the current guided through the current conductor 2 is shown in both cases, with and without the metal plate 8. Figure 2B As can be seen from the frequency response shown, the phase error in the sensor device according to the invention may be smaller than that in a conventional sensor device. Therefore, the sensor device according to the invention can provide an improved frequency response. In the example, a typical frequency can be in the range of approximately 0 kHz to approximately 2 kHz. In this case, in Figure 2A and Figure 2B The exemplary, typical frequency values ​​of approximately 2kHz are marked in the text.

[0023] In conventional sensor devices, the frequency response can be optimized by reducing the width of the conductive rails within the sensor region (e.g., by contracting the sides formed in the current conductor). However, a drawback of this principle is that the reduced cross-section of the current conductor may lead to higher power losses in the sensor region, potentially resulting in overheating. In contrast, the sensor device according to this disclosure can achieve a suitable improvement in frequency response as described, without reducing the cross-section of the current conductor. This provides for improved heat flow through the current conductor and improved mechanical stability of the current conductor. Furthermore, the sensor device according to the invention can be, in particular, coreless and does not necessarily require a magnetic field concentrator. The sensor device can be a coreless current sensor, which can be integrated into an external conductive rail.

[0024] Figure 3 A method for manufacturing a sensor device according to the present invention is shown. The method is shown in a general form and can be used, for example, to manufacture the sensor device 100 of FIG. 1. The method can be extended with one or more aspects described in conjunction with other examples discussed herein. The order of the various method steps can be changed, as long as this is technically meaningful.

[0025] In step 28, a current conductor 2, designed to guide current, can be arranged. In a further step 30, a metal plate 8 can be arranged above the current conductor 2. In a further step 32, a differential magnetic field sensor chip 4 can be arranged below the metal plate 8 in the opening 6 of the current conductor 2. The magnetic field sensor chip 4 can be designed to detect the magnetic field 10 generated by the current.

[0026] In the first example, in an optional step, the current conductor 2 and the metal plate 8 can be encapsulated in a first encapsulation material 14, and the magnetic field sensor chip 4 can be disposed in a recess 18 of the first encapsulation material 14. In the second example, in an optional step, the metal plate 8, the current conductor 2, and the magnetic field sensor chip 4 can be encapsulated in a common encapsulation material.

[0027] Example

[0028] The sensor device and related manufacturing method according to the present invention are then described with reference to examples.

[0029] Example 1 is a sensor device comprising: a current conductor designed to guide current; a differential magnetic field sensor chip disposed in an opening in the current conductor and designed to detect a magnetic field generated by the current; and a metal plate disposed above the current conductor and the magnetic field sensor chip.

[0030] Example 2 is a sensor device according to Example 1, wherein: a current conductor extends around an opening in a first direction, and a magnetic field sensor chip includes two sensor elements spaced apart in a second direction perpendicular to the first direction, and the two sensor elements are sensitive in a third direction perpendicular to both the first and second directions.

[0031] Example 3 is a sensor device according to Example 1 or 2, wherein the first sensor element of the magnetic field sensor chip is arranged closer to the metal plate than the second sensor element of the magnetic field sensor chip.

[0032] Example 4 is a sensor device according to one of the examples above, wherein the sensor elements of the magnetic field sensor chip are arranged offset relative to the center of the opening.

[0033] Example 5 is a sensor device according to one of the examples above, wherein a metal plate and a current conductor are encapsulated in a first encapsulation material.

[0034] Example 6 is a sensor device according to Example 5, wherein a magnetic field sensor chip is disposed outside a first encapsulation material.

[0035] Example 7 is a sensor device according to Example 5 or 6, wherein the first encapsulation material has a recess and a magnetic field sensor chip is disposed in the recess.

[0036] Example 8 is a sensor device according to one of the foregoing examples, wherein a magnetic field sensor chip is encapsulated in a second encapsulation material and a current conductor is arranged outside the second encapsulation material.

[0037] Example 9 is a sensor device according to one of Examples 1 to 4, wherein a metal plate, a current conductor, and a magnetic field sensor chip are encapsulated in a common encapsulation material.

[0038] Example 10 is a sensor device according to one of the foregoing examples, wherein a magnetic field sensor chip is mounted on a circuit board and the circuit board is perpendicular to the current conductor.

[0039] Example 11 is a sensor device according to one of Examples 2 to 10, wherein the current conductor has a constant dimension in a third direction around the opening.

[0040] Example 12 is a sensor device according to one of Examples 2 to 11, wherein the dimension of the metal plate in the third direction is larger than the dimension of the current conductor in the third direction.

[0041] Example 13 is a sensor device according to one of Examples 2 to 12, wherein the dimension of the metal plate in a third direction is greater than the dimension of the metal plate in a first direction.

[0042] Example 14 is a sensor device according to one of the examples above, wherein the metal plate does not have an opening.

[0043] Example 15 is a sensor device according to one of the foregoing examples, wherein a metal plate extends parallel to a current conductor.

[0044] Example 16 is a sensor device according to one of Examples 1 to 14, wherein the metal plate is at least partially bent in the direction of the current conductor.

[0045] Example 17 is a sensor device according to one of the examples above, wherein the metal plate is made of at least one of copper, aluminum or an alloy thereof.

[0046] Example 18 is a sensor device according to one of the examples above, wherein the sensor device is coreless and does not have a magnetic field concentrator.

[0047] Example 19 is a method for manufacturing a sensor device, wherein the method includes: arranging a current conductor designed to guide current; arranging a metal plate above the current conductor; and arranging a differential magnetic field sensor chip in an opening in the current conductor below the metal plate, wherein the magnetic field sensor chip is designed to detect a magnetic field generated by the current.

[0048] Example 20 is the method according to Example 19, further comprising: encapsulating a current conductor and a metal plate in a first encapsulation material; and arranging a magnetic field sensor chip in a recess of the first encapsulation material.

[0049] Example 21 is based on the method of Example 19, and further includes: encapsulating a metal plate, a current conductor, and a magnetic field sensor chip in a common encapsulation material.

[0050] It should be noted that the specification and accompanying drawings only illustrate the principles of the proposed methods and apparatus. Those skilled in the art will be able to implement different arrangements, which, although not explicitly described or shown herein, still embody the principles of the invention and are included within its scope. Furthermore, all examples and embodiments outlined in this document are substantially and explicitly for illustrative purposes only, in order to assist the reader in understanding the principles of the proposed methods and apparatus. In addition, all statements in this document describing the principles, aspects, and embodiments of the invention, as well as specific examples thereof, should also include their equivalents.

Claims

1. A sensor device, comprising: a current conductor (2) designed for conducting an electric current; a differential magnetic field sensor chip (4) arranged in an opening (6) of the current conductor (2) and designed for detecting a magnetic field (10) generated by the electric current; and a metal plate (8) arranged above the current conductor (2) and the magnetic field sensor chip (4).

2. The sensor device according to claim 1, wherein the current conductor (2) extends in a first direction around the opening (6), the magnetic field sensor chip (4) comprises two sensor elements (12A, 12B) spaced apart in a second direction perpendicular to the first direction, and the two sensor elements (12A, 12B) are sensitive in a third direction perpendicular to the first direction and perpendicular to the second direction. a first sensor element (12A) of the magnetic field sensor chip (4) is arranged closer to the metal plate (8) than a second sensor element (12B) of the magnetic field sensor chip (4).

3. The sensor device of claim 1 or 2, wherein, the sensor elements (12A, 12B) of the magnetic field sensor chip (4) are arranged offset with respect to a center of the opening (6).

4. The sensor device according to any one of the preceding claims, wherein, the metal plate (8) and the current conductor (2) are encapsulated in a first encapsulation material (14).

5. The sensor device according to any one of the preceding claims, wherein, the magnetic field sensor chip (4) is arranged outside the first encapsulation material (14).

6. The sensor device of claim 5, wherein, the first encapsulation material (14) has a recess (18) and the magnetic field sensor chip (4) is arranged in the recess (8).

7. The sensor device of claim 5 or 6, wherein, the magnetic field sensor chip (4) is encapsulated in a second encapsulation material (16) and the current conductor (2) is arranged outside the second encapsulation material (16).

8. The sensor device according to any one of the preceding claims, wherein, the metal plate (8), the current conductor (2) and the magnetic field sensor chip (4) are encapsulated in a common encapsulation material.

9. The sensor device according to any one of claims 1 to 4, wherein, the magnetic field sensor chip (4) is mounted on a circuit board (20) and the circuit board (20) extends perpendicular to the current conductor (2).

10. The sensor device according to any one of the preceding claims, wherein, the current conductor (2) has a dimension around the opening (6) in a third direction that is constant.

11. The sensor device according to any one of claims 2 to 10, wherein, a dimension of the metal plate (8) in the third direction is larger than a dimension of the current conductor (2) in the third direction.

12. The sensor device according to any one of claims 2 to 11, wherein, a dimension of the metal plate (8) in the third direction is larger than a dimension of the metal plate (8) in the first direction.

13. The sensor device according to any one of claims 2 to 12, wherein, the metal plate (8) has no opening.

14. The sensor device according to any one of the preceding claims, wherein, the metal plate (8) extends parallel to the current conductor (2).

15. The sensor device according to any one of the preceding claims, wherein, the metal plate (8) is at least partially curved in direction of the current conductor (2).

16. The sensor device according to any one of claims 1 to 14, wherein, the metal plate (8) is made of at least one of copper, aluminum or an alloy thereof.

17. The sensor device according to any one of the preceding claims, wherein, the sensor device is coreless and has no magnetic field concentrator.

18. The sensor device according to any one of the preceding claims, wherein, the method comprises:

19. A method for manufacturing a sensor device, wherein arranging a current conductor (2) designed for conducting an electric current; arranging a metal plate (8) above the current conductor (2); and ​ A differential magnetic field sensor chip (4) is arranged in an opening of the current conductor (2) below the metal plate (8), wherein the magnetic field sensor chip (4) is designed to detect a magnetic field generated by the current.

20. The method according to claim 19, further comprising: encapsulating the current conductor (2) and the metal plate (8) in a first encapsulation material (14); and arranging the magnetic field sensor chip (4) in a recess (18) of the first encapsulation material (14).

21. The method according to claim 19, further comprising: encapsulating the metal plate (8), the current conductor (2) and the magnetic field sensor chip (4) in a common encapsulation material.

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