Hall current sensor for on-chip current measurement and manufacturing method thereof

Abstract

The embodiment of the invention provides a Hall current sensor for on-chip current measurement and a manufacturing method thereof, and belongs to the technical field of semiconductor magnetic sensing. The Hall current sensor comprises two Hall units which are arranged on the two sides of the upper surface of the current row in pairs in an attached mode, and each Hall unit is at least one Hall array; two ends of the first magnetic gathering part are respectively arranged on the upper magnetic induction surfaces of the two Hall units; the second magnetism gathering part has a concave cross section to wrap the current bar, and two ends of the second magnetism gathering part are respectively arranged on the lower magnetic induction surfaces of the two Hall units; the overlapped parts of the projections of the first magnetism gathering part and the second magnetism gathering part on the corresponding magnetic induction surfaces are positioned in Hall sensitive areas of the two Hall units; a current magnetic field is subjected to magnetism gathering through the first magnetism gathering part and the second magnetism gathering part to form a magnetic flux loop penetrating through the Hall sensitive area, so that the Hall unit senses the magnetic field and converts the magnetic field into a signal through a circuit to be output. The Hall current sensor efficiently concentrates a current magnetic field to avoid the influence of a skin effect on current measurement.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor magnetic sensing, and in particular to a Hall current sensor for on-chip current measurement and a manufacturing method thereof. BACKGROUND

[0002] The Hall built-in current row current sensing technology is suitable for various semiconductor sensing fields, and in particular for detection of small currents on-chip.

[0003] The existing on-chip current Hall sensor device places a Hall on both sides of a current row to detect a z-axis magnetic field and combines a differential calculation to improve gain and reduce interference.

[0004] However, when the current frequency in the current row changes, such as a variable frequency direct current or a frequency periodically changing alternating current, the Hall sensor is affected by the skin effect of the frequency changing current or the frequency changing magnetic field. At this time, the current is more concentrated on the surface of the current row as the frequency is higher, and the current is more concentrated in the center of the current row as the frequency is lower, and the magnetic field distribution also changes. In this case, the magnetic flux loop passing through the Hall sensor and the magnetic field strength that can be sensed through the Hall sensitive area will change, which will cause unstable sensing performance and significant frequency errors, thereby seriously affecting the current detection result.

[0005] In view of this, a new type of Hall current sensor for on-chip current measurement and a manufacturing method thereof are proposed to solve the above problems in whole or in part. SUMMARY

[0006] In order to solve at least one aspect of the above problems and defects in the prior art, embodiments of the present application provide a Hall current sensor for on-chip current measurement and a manufacturing method thereof, which is suitable for direct current and alternating current, and in particular for current magnetic field sensing with continuously fluctuating current frequency in the current row. The Hall current sensor realizes efficient magnetic concentration by arranging a first magnetic concentration part above and a second magnetic concentration part below the pair of Hall units arranged in the horizontal direction, so that the magnetic flux loop always passes through the Hall sensitive area of the pair of Hall units with a stable expected magnetic flux, effectively avoiding the influence of the skin effect of the current caused by the frequency change on the Hall detection signal, thereby greatly reducing the frequency error, and improving the Hall sensing sensitivity due to the increase in magnetic concentration strength. The technical solution is as follows:

[0007] According to an aspect of the present application, a Hall current sensor for on-chip current measurement is provided. The Hall current sensor comprises:

[0008] two Hall units arranged in pairs on both sides of the upper surface of the current row, each of the two Hall units being at least one group of Hall arrays;

[0009] a first magnetic concentrating part, two ends of which are respectively arranged on the upper magnetic induction surfaces of the two Hall units;

[0010] a second magnetic concentrating part, having a concave cross section, wrapping the current bar and having two protruding ends respectively arranged on the lower magnetic induction surfaces of the two Hall units;

[0011] the overlapping part of the projections of the first magnetic concentrating part and the second magnetic concentrating part on the corresponding magnetic induction surfaces is located in the Hall sensitive region of the two Hall units;

[0012] The current magnetic field in the current bar is concentrated by the first magnetic concentrating part and the second magnetic concentrating part to form a magnetic flux loop passing through the Hall sensitive region, and the two Hall units sense the current magnetic field to output Hall signals which are converted by the Hall circuit into signals proportional to the current in the current bar.

[0013] In some embodiments, alternatively, each Hall unit is at least one group of Hall arrays, wherein each group of Hall arrays in the at least one group of Hall arrays includes at least two Halls arranged side by side. The at least two Halls are connected in series through signal electrodes or connected in parallel through signal electrodes.

[0014] In some embodiments, alternatively, the at least two Halls are a group of Hall arrays composed of cross-shaped Halls, or the at least two Halls are a group of Hall arrays composed of strip-shaped Halls; the total length L of one Hall unit composed of at least one group of Hall arrays is ≥800μm.

[0015] In some embodiments, alternatively, the Halls in each Hall unit are packaged Hall elements or Hall bare chips. The strip-shaped Halls in each Hall unit are packaged strip-shaped Hall elements or strip-shaped Hall bare chips.

[0016] In some embodiments, in particular, a differential Hall pair is formed by connecting the Halls in each Hall unit in series through working electrodes. The output terminals of the two Hall units are connected in differential series to a signal conditioning circuit arranged on a circuit substrate.

[0017] In some embodiments, preferably, in the Hall sensitive region of each Hall unit, the length L0 of the overlapping part of the projections of the first magnetic concentrating part and the second magnetic concentrating part on the corresponding magnetic induction surfaces is in the range of 0.7-1.0 times the total length L of the corresponding Hall unit.

[0018] In some embodiments, preferably, the width W1 of the first magnetic concentrating part is in the range of 1.5W≤W1≤30W, and the width W2 of the second magnetic concentrating part is in the range of 1.5W≤W2≤30W, where W is the width of each Hall unit. And the width of the second magnetic concentrating part is greater than the width of the first magnetic concentrating part.

[0019] According to another aspect of the present application, a manufacturing method of a Hall current sensor for on-chip current measurement is provided. The manufacturing method is used to manufacture the Hall current sensor described in the above aspects. The manufacturing method comprises:

[0020] providing a circuit substrate and disposing a slot through the circuit substrate at a position corresponding to the arranged pair of Hall cells;

[0021] manufacturing two Hall cells on the circuit substrate, wherein each Hall cell is at least one Hall array;

[0022] bonding the circuit substrate on a mounting surface of the current bar;

[0023] mounting the first magnetic concentrating part with its two ends disposed on the upper magnetic induction surfaces of the two Hall cells, respectively;

[0024] mounting the second magnetic concentrating part with a concave cross section to wrap the current bar and its protruding two ends inserted into the slot of the circuit substrate and disposed on the lower magnetic induction surfaces of the two Hall cells, respectively;

[0025] mounting a signal conditioning circuit on the circuit substrate and electrically connecting it with the two Hall cells;

[0026] molding the current bar, the circuit substrate, the two Hall cells, the first magnetic concentrating part and the second magnetic concentrating part to integrate to obtain the Hall current sensor.

[0027] In some embodiments, specifically, the part of the concave cross section of the second magnetic concentrating part in the vertical direction is in the shape of a trapezoidal cross section, the length of the trapezoidal cross section abutting on the lower magnetic induction surface of each Hall cell is L1 and L1≤ the total length L of the Hall cell, and the length of the trapezoidal cross section away from each Hall cell is L2, wherein the length of L2 ranges from 1.2L1 to 6L1.

[0028] In some embodiments, specifically, when the Hall cells in the manufactured Hall current sensor use packaged cross-shaped Hall elements or packaged strip-shaped Hall elements: the width of the first magnetic concentrating part at the center of symmetry of the two Hall cells is 1.5-6 times the width of the first magnetic concentrating part at the two ends. The height of the first magnetic concentrating part at the center of symmetry of the two Hall cells is 1.2-3 times the height of the first magnetic concentrating part at the two ends. The width of the second magnetic concentrating part away from one side of each Hall cell is 1.5-6 times the width of the second magnetic concentrating part abutting on the lower magnetic induction surface of each Hall cell.

[0029] The Hall current sensor for on-chip current measurement and the manufacturing method thereof provided by the embodiments of the present application have at least one of the following advantages or part of the advantages:

[0030] (1) By setting the first and second magnetic concentrating parts above and below the pair of Hall units arranged horizontally, efficient magnetic concentration is achieved, so that the magnetic flux loop always passes through the Hall sensitive area of the pair of Hall units with a stable expected magnetic flux, effectively avoiding the skin effect of the current with varying frequency, thereby greatly reducing the frequency error and improving the Hall sensing sensitivity;

[0031] (2) By arranging a Hall array or a strip-shaped Hall array with equivalent length inside the pair of Hall units and performing series differential, the Hall sensing sensitivity can be further improved and interference can be reduced;

[0032] (3) In the Hall unit, the series or parallel connection between the Halls can be flexibly arranged through the signal electrode, which can adapt to various types of on-chip current array scenarios, and the cross-shaped Hall or strip-shaped Hall of the array effectively improves the gain of the current magnetic field and reduces the influence of different current frequencies on the magnetic field detection;

[0033] (4) By combining the overall size ratio of the pair of Hall units, the relative width of the first and second magnetic concentrating parts can be designed, so that an effective and stable magnetic flux loop can be formed, thereby realizing the concentration and stable convergence of the current magnetic field;

[0034] (5) By setting the second magnetic concentrating part to be wider and longer away from the bottom of the Hall and gradually smaller in width and length as it approaches the top of the Hall, the magnetic field can be further concentrated in the Hall sensitive area of the pair of Hall units;

[0035] (6) By using the second magnetic concentrating part with a concave cross-section to completely wrap the current array and cooperating with the first magnetic concentrating part projected and overlapped in the Hall sensitive area, a magnetic flux loop without gap can be formed, and the magnetic concentration range is larger and the measurement sensitivity is higher;

[0036] (7) The Hall current sensor is suitable for on-chip current measurement of small current (within hundreds of amperes), has high sensing sensitivity, and can further reduce the integrated size and improve the miniaturization and integration degree by using a Hall bare chip array to form a Hall unit. BRIEF DESCRIPTION OF DRAWINGS

[0037] These and / or other aspects and advantages of the present application will become apparent and readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0038] Figure 1 FIG. 1 is a cross-sectional structure diagram of a Hall current sensor for on-chip current measurement according to Embodiment 1 of the present application;

[0039] Figure 2 FIG. 2 is a top view of the structure of the Hall current sensor shown in FIG. 1; Figure 1

[0040] ​Figure 3 A schematic diagram of one structure of a Hall cell in a Hall current sensor according to an embodiment of the present application;

[0041] Figure 4 A schematic diagram of another structure of a Hall cell in a Hall current sensor according to an embodiment of the present application;

[0042] Figure 5 A schematic diagram of one connection structure of a pair of two Hall cells in a Hall current sensor according to an embodiment of the present application;

[0043] Figure 6 A cross-sectional structure schematic diagram of a Hall current sensor for on-chip current measurement according to embodiment 2 of the present application;

[0044] Figure 7 A top view of the structure of the Hall current sensor shown in Figure 6

[0045] Figure 8 A flow chart of a manufacturing method of a Hall current sensor for on-chip current measurement according to an embodiment of the present application. DETAILED DESCRIPTION

[0046] The technical solutions of the present application will be further described in detail below by way of examples in conjunction with the accompanying drawings. In the description, identical or similar reference numerals indicate identical or similar components. The following description of the embodiments of the present application with reference to the accompanying drawings is intended to explain the general inventive concept of the present application, and should not be construed as a limitation of the present application.

[0047] It should also be understood that, although the terms “first”, “second”, “third” and the like can be used herein to describe various components, including two or more of such components, the components should not be construed as being limited to these terms. These terms are only used to distinguish one component from another. The description of “up”, “down”, “left”, “right”, and the like, is only for the purpose of illustrating the relative position of the components, and should not be construed as a limitation of the present application.

[0048] The Hall current sensor for on-chip current measurement and the manufacturing method thereof provided by the embodiments of the present application achieve efficient magnetic concentration by respectively arranging a first magnetic concentration part and a second magnetic concentration part above and below a pair of Hall cells arranged in a horizontal direction, so that the magnetic flux loop always passes through the Hall sensitive area of the pair of Hall cells with a stable expected magnetic flux. The influence of the skin effect of the current with varying frequency on the current measurement is effectively avoided, thereby greatly reducing the frequency error and improving the Hall sensing sensitivity.

[0049] ​According to one aspect of the present application, there is provided a Hall current sensor 100 for on-chip current measurement.

[0050] Embodiment 1

[0051] Referring to Figure 1 , a cross-sectional structure of the overall Hall current sensor 100 for on-chip current measurement of Embodiment 1 is shown. Meanwhile, referring to Figure 2 , a top view of the overall structure of the Hall current sensor 100 of Figure 1 is shown.

[0052] As shown in Figure 1 and Figure 2 , the Hall current sensor 100 is mainly composed of a pair of two Hall units (a first Hall unit 11 and a second Hall unit 12) horizontally arranged on the upper surface of the current row 200, an upper first magnetic concentrating part 20, a lower second magnetic concentrating part 30 having a concave cross-section, and a circuit substrate 40.

[0053] The first Hall unit 11 and the second Hall unit 12 are arranged in pairs on both sides of the upper surface of the current row 200, and each of the two Hall units is at least one group of Hall arrays (for example, a cross-shaped Hall array as shown in Figure 3 or Figure 4 , for example, a bar-shaped Hall array as shown in Figure 5 ).

[0054] The first magnetic concentrating part 20 is arranged on the upper magnetic induction surface of the first Hall unit 11 and the second Hall unit 12, respectively;

[0055] The second magnetic concentrating part 30 has a concave cross-section, and the second magnetic concentrating part 30 completely wraps the current row 200, and the two protruding ends thereof are arranged on the lower magnetic induction surface of the first Hall unit 11 and the second Hall unit 12, respectively;

[0056] The overlapping part of the projections of the first magnetic concentrating part 20 and the second magnetic concentrating part 30 on the corresponding magnetic induction surfaces is located in the Hall sensitive area of the first Hall unit 11 and the second Hall unit 12;

[0057] The current magnetic field in the current row 200 is concentrated by the first magnetic concentrating part 20 and the second magnetic concentrating part 30 to form a magnetic flux loop passing through the Hall sensitive area, and the two Hall units (the first Hall unit 11 and the second Hall unit 12) sense the current magnetic field to output Hall signals, which are converted into signals proportional to the current in the current row 200 by the Hall circuit in the circuit substrate 40.

[0058] In one example, alternatively, each Hall unit (taking the first Hall unit 11 as an example) is at least one group of Hall arrays, wherein each group of Hall arrays in the at least one group of Hall arrays includes at least two Halls arranged side by side. The at least two Halls can be connected in series or in parallel.

[0059] Referring to Figure 3 , a specific structure of a Hall unit (taking the first Hall unit 11 as an example) of one embodiment is shown, in which several Halls (cross-shaped Halls) are electrically connected in parallel to form the first Hall unit 11.

[0060] As shown in Figure 3 , when the Halls A, B and C in the Hall array are closely arranged in a line and then connected in parallel, the Hall array includes two signal terminals and is provided with the first signal electrode 111 and the second signal electrode 112, and also includes two output terminals and is provided with the first working electrode a1 and the second working electrode a2. The parallel connection of the Halls A, B and C is realized through the first signal electrode 111 and the second signal electrode 112, and the first working electrode a1 and the second working electrode a2 are used for differential connection with a counterpart Hall unit. After the connection of the first Hall unit 11 is completed, the total length of the Hall unit thereof is L.

[0061] Referring to Figure 4 , a specific structure of a Hall unit (taking the first Hall unit 11’ as an example) of another embodiment is shown, in which several Halls (cross-shaped Halls) are electrically connected in series to form the first Hall unit 11’.

[0062] As shown in Figure 4 , when the Halls A, B and C in the Hall array are closely arranged in a line and then connected in series, the Hall array includes six signal terminals and is provided with the third signal electrode 113, the fourth signal electrode 114, the fifth signal electrode 115, the sixth signal electrode 116, the seventh signal electrode 117 and the eighth signal electrode 118 connected in series, and also includes two output terminals and is provided with the first working electrode a1’ and the second working electrode a2’. The series connection of the Halls A, B and C is realized through the third signal electrode 113 to the eighth signal electrode 118, and the first working electrode a1’ and the second working electrode a2’ are used for differential connection with a counterpart Hall unit. After the connection of the first Hall unit 11’ is completed, the total length of the Hall unit thereof is L.

[0063] Exemplarily, Figure 3 and Figure 4The connection structure of three Halls (Hall A, Hall B and Hall C) connected in series is shown. The number of Hall arrays can be two, three or more. In addition, a group, two groups, three groups or more of the above Hall arrays can also be arranged in, for example, the first Hall unit 11. The present example only provides some illustrative examples, and those skilled in the art should not be construed as limiting the present application.

[0064] In one example, alternatively, a bar-shaped Hall can also be used to form a Hall array in a group of Hall arrays of one Hall unit. For example Figure 5 The array structure of the Hall array of the first Hall unit 11 or the second Hall unit 12 shown in example ②. The arrangement and electrical connection of at least two bar-shaped Halls can refer to the above-mentioned embodiment using cross-shaped Halls, which will not be described here.

[0065] In one example, preferably, the total length L of at least one group of Hall arrays forming one Hall unit is ≥ 800 μm, and further preferably, the total length L is ≥ 1 mm.

[0066] In the overall structure of the Hall current sensor 100, in order to form a stable magnetic flux loop that is not affected by the fluctuation or change of the current frequency, the total length L of the Hall unit needs to be designed in cooperation with the structure size of the first magnetic concentrating part 20 and the second magnetic concentrating part 30 to have a certain length value. When the current frequency changes, the magnetic lines of force expand outward or shrink inward, and the relatively fixed magnetic flux passing through the magnetic induction sensitive area of the Hall unit can be maintained, so that the Hall sensing is no longer affected by the current frequency (skin effect) and has a stable magnetic flux.

[0067] Referring to Figure 5 , the series connection differential structure of a pair of two Hall units (the first Hall unit 11 and the second Hall unit 12) of one embodiment is shown.

[0068] In combination with Figures 3-5 , in one example, specifically, the first Hall unit 11 and the second Hall unit 12 are connected in series through the electrodes to form a differential Hall pair. For example, the second working electrode a2 of the first Hall unit 11 and the first working electrode b1 of the second Hall unit 12 are connected in series, and the signal electrodes of the two are connected in series in turn. The output terminals of the pair of Hall units (the first working electrode a1 of the first Hall unit 11 and the second working electrode b2 of the second Hall unit 12) are connected in a differential series connection mode into the signal conditioning circuit 42 (for example Figure 2 , the circuit substrate) provided on the circuit substrate 40.

[0069] In one example, preferably, the length L0 of the overlapping part of the projections of the first and second magnetic concentrating parts 20 and 30 on the corresponding magnetic induction surfaces is in the range of 0.7-1.0 times the total length L of each Hall cell (e.g. the first Hall cell 11). Meanwhile, in designing the specific structure and specific size of the above two magnetic concentrating parts, on one hand, it is necessary to ensure that the magnetic concentrating parts have vertical projection overlap on the upper and lower magnetic induction surfaces of the same Hall cell. On the other hand, it is also necessary to ensure that the overlapping area is located in the Hall sensitive area of the Hall cell and does not exceed the Hall sensitive area.

[0070] As shown in FIG. 1, in one example, preferably, the second magnetic concentrating part 30 has a concave cross-section as a whole. Figure 1

[0071] In other words, the length of the trapezoidal cross-section in this place is within the range of the total length of the Hall cell, thereby ensuring that the magnetic field converged by the second magnetic concentrating part 30 completely passes through the Hall cell at this place. Even if the current frequency changes so that the magnetic field expands outward or shrinks inward, it can be ensured that the Hall cell obtains the expected and stable magnetic flux to maintain the expected and stable magnetic concentration strength.

[0072] The length of the trapezoidal cross-section away from the bottom of the Hall current sensor 100 of each Hall cell (e.g. the first Hall cell 11) is L2, wherein the length of L2 is in the range of 1.2L1-10L1, and further preferably, the length of L2 is in the range of 1.5L1-6L1. Figure 1

[0073] As shown in FIG. 1, in one example, preferably, the width W1 of the first magnetic concentrating part 20 is in the range of 1.5W≤W1≤30W, and the width W2 of the second magnetic concentrating part 30 is in the range of 1.5W≤W2≤30W, wherein W is the width of each Hall cell (e.g. the first Hall cell 11). And the width of the second magnetic concentrating part 30 is greater than the width of the first magnetic concentrating part 20. Figure 2 In one example, preferably, the length L0 of the overlapping part of the projections of the first and second magnetic concentrating parts 20 and 30 on the corresponding magnetic induction surfaces is in the range of 0.7-1.0 times the total length L of each Hall cell (e.g. the first Hall cell 11). Meanwhile, in designing the specific structure and specific size of the above two magnetic concentrating parts, on one hand, it is necessary to ensure that the magnetic concentrating parts have vertical projection overlap on the upper and lower magnetic induction surfaces of the same Hall cell. On the other hand, it is also necessary to ensure that the overlapping area is located in the Hall sensitive area of the Hall cell and does not exceed the Hall sensitive area.

[0074] Figure 1 ​​​The magnetic flux loop corresponding to the change of the frequency of the current in the current row 200 is shown exemplarily. When the magnetic field of the current with different frequencies is sensed, the magnetic force lines of the magnetic field can pass through the Hall sensitive area of the pair of two Hall units (the first Hall unit 11 and the second Hall unit 12) regardless of the change of the current and the frequency of the magnetic field, and regardless of whether the plurality of Halls inside each Hall unit are in parallel or in series, the output signal of the Hall is the superposition or average of the sensing signals of the Halls, and the change of the magnetic field distribution does not affect the structure of the final Hall signal. Therefore, the change of the magnetic field distribution caused by the skin effect due to the change of the current frequency can be ignored. At the same time, since the upper and lower magnetic concentrating structures completely wrap the current row 200 and the pair of Hall units, the sensitivity can be further improved. When the Hall current sensor 100 is used for current detection, the magnetic flux loop has almost no gap and completely passes through the Hall sensitive area of the Hall unit, and the magnetic concentrating range is larger, so the sensitivity of the measurement is significantly improved compared with the existing Hall sensor.

[0075] In one example, alternatively, the Hall in each Hall unit is a packaged Hall element (i.e. integrated packaging is performed through the metal pins outside the packaging structure for electrical connection) or a Hall bare chip (i.e. an unpackaged structure, which can be electrically connected through circuit wiring or metal wire bonding). Similarly, a cross-shaped Hall (packaged or bare chip) can be used in each Hall unit, and a bar-shaped Hall (packaged or bare chip) can also be used.

[0076] In the above embodiment 1, a cross-shaped Hall bare chip or a bar-shaped Hall bare chip is preferably used. The following embodiment 2 focuses on the matching setting of the upper and lower magnetic concentrating part structures when a packaged cross-shaped Hall element or a packaged bar-shaped Hall element is used.

[0077] Embodiment 2

[0078] Referring to Figure 6 , the cross-sectional structure of the overall Hall current sensor 100a for on-chip current measurement of embodiment 2 is shown. At the same time, referring to Figure 7 , the top view of the overall structure of the Hall current sensor 100a of Figure 7 is shown.

[0079] As shown in Figure 6 and Figure 7 , the Hall current sensor 100a is mainly composed of a pair of two Hall units (the first Hall unit 11a and the second Hall unit 12a) arranged horizontally above the surface of the current row 200, the first magnetic concentrating part 20a arranged against the two Hall units, the second magnetic concentrating part 30a with a concave cross section below, and the circuit substrate 40a.

[0080] For packaged Hall elements, the package body and lead electrodes make the device larger than the bare Hall chip. Therefore, the packaged Hall element needs to match the larger magnetic concentrating structure with upper and lower parts. At the same time, in order to effectively concentrate the magnetic field, the cross-sectional shape of the magnetic concentrating structure is also more complex. For example, a gradient cross-sectional structure is needed in both height and width to collect more current magnetic field and improve sensitivity.

[0081] In one example, specifically, when the two Hall cells (the first Hall cell 11 a and the second Hall cell 12 a ) in the manufactured Hall current sensor 100 a use a packaged cross-shaped Hall element or a packaged strip-shaped Hall element:

[0082] The width W of the first magnetic concentrating portion 20a at the symmetric center of the two Hall elements is 1a is its width W at both ends 1b 1.5-6 times of that.

[0083] The height H of the first magnetic concentrating portion 20a at the symmetric center of the two Hall elements is 1a is its height H at both ends 1b 1.2-3 times of that.

[0084] The second magnetic concentrating portion 30a is located on a side away from each Hall element (i.e. Figure 6 The width W of the bottom of the Hall current sensor 100a is shown 2a is the width W of the lower magnetic sensing surface of each Hall unit. 2b 1.5-6 times of that.

[0085] According to another aspect of the present invention, a method for manufacturing a Hall current sensor for on-chip current measurement is provided. The manufacturing method is used to manufacture the Hall current sensors described in the above embodiments (such as the Hall current sensor 100 and the Hall current sensor 100a). Figure 8 Taking the manufacturing of the Hall current sensor 100 of Example 1 as an example, the process steps of the manufacturing method specifically include:

[0086] Step 301: providing a circuit substrate 40 (including a base substrate 41 ) and setting slots penetrating the circuit substrate 40 at positions corresponding to the paired Hall elements (the first Hall element 11 and the second Hall element 12 );

[0087] Step 302: manufacturing two pairs of Hall elements (a first Hall element 11 and a second Hall element 12 ) on a circuit substrate 40 , wherein each Hall element is at least one set of Hall arrays;

[0088] Step 303: Bonding the circuit substrate 40 to the mounting surface of the current bus 200;

[0089] Step 304: install the first magnetic concentrating part 20 with its two ends respectively arranged on the upper magnetic induction surfaces of the two Hall units;

[0090] Step 305: install the second magnetic concentrating part 30 with a concave cross section to wrap the current bar 200 and its protruding two ends inserted into the slots of the circuit substrate 40 to be arranged on the lower magnetic induction surfaces of the two Hall units respectively;

[0091] Step 306: install the signal conditioning circuit 42 on the circuit substrate 40 and electrically connect with the two Hall units;

[0092] Step 307: encapsulate the current bar 200, the circuit substrate 40, the two Hall units (the first Hall unit 11 and the second Hall unit 12), the first magnetic concentrating part 20 and the second magnetic concentrating part 30 to obtain the Hall current sensor 100.

[0093] In Figure 2 , it can be seen that after the encapsulation of step 307, the circuit substrate 40 includes the substrate 41, the signal conditioning circuit 42 and the pin electrode 43.

[0094] In Figure 7 , it can be seen that if a packaged Hall element is used in the Hall unit, since its internal circuit substrate 40a has been integrated with all the integrated circuits 41a for sensing and outputting the current measurement value of the Hall current sensor 100a, such as signal conditioning circuit or signal conversion circuit, etc., the overall pin electrode 43a can be arranged outside the encapsulation body after overall encapsulation.

[0095] The cross-sectional shape and the overall size of the upper and lower parts of the magnetic concentrating structure can refer to the preferred parameter settings in the above-mentioned embodiments 1 and 2. Meanwhile, those skilled in the art can understand that the design of the preferred or specific magnetic concentrating structure needs to be matched according to the actual on-chip current bar scene and measurement requirements. Here, only some illustrative examples are provided, and those skilled in the art should not understand it as a limitation of the present application.

[0096] Through the manufacturing method, the slot is opened on the circuit substrate 40 for fixing the second magnetic concentrating part 30 to wrap the current bar 200 and the pair of two Hall units (the first Hall unit 11 and the second Hall unit 12) together to form a straight-through type magnetic concentrating structure, so that the current in the current bar forms a stable magnetic concentrating loop in the magnetic induction sensitive area of the Hall unit pair when passing through the straight-through type magnetic concentrating structure. At the same time, it can also effectively concentrate the magnetic field, realize higher sensing sensitivity in a smaller on-chip space and be able to resist the influence of the skin effect of the current on the Hall sensing.

[0097] The Hall current sensor for on-chip current measurement and the manufacturing method thereof provided by the embodiments of the present application have at least one or part of the following advantages:

[0098] (1) The first magnetic concentrating part and the second magnetic concentrating part arranged above and below the pair of Hall units in the horizontal direction respectively realize efficient magnetic concentration, so that the magnetic flux loop always passes through the Hall sensitive area of the pair of Hall units with a stable expected magnetic flux, effectively avoiding the skin effect of the current with varying frequency, thereby greatly reducing the frequency error and improving the Hall sensing sensitivity;

[0099] (2) The Hall array arranged inside the pair of Hall units or the strip-shaped Hall array with equivalent length arranged and connected in series can further improve the Hall sensing sensitivity and reduce interference;

[0100] (3) The series or parallel connection between the Hall units can be flexibly arranged through the signal electrode, which can adapt to various types of on-chip current row scenarios, and the cross-shaped Hall or strip-shaped Hall of the array effectively improves the gain of the current magnetic field and reduces the influence of different current frequencies on the magnetic field detection;

[0101] (4) The relative width of the first magnetic concentrating part and the second magnetic concentrating part can be designed by combining the overall size ratio of the pair of Hall units, so as to form an effective and stable magnetic flux loop, thereby realizing the concentration and stable convergence of the current magnetic field;

[0102] (5) By setting the second magnetic concentrating part to be wider and longer away from the bottom of the Hall and gradually smaller in width and length as approaching the top of the Hall, the magnetic field can be further concentrated in the Hall sensitive area of the pair of Hall units;

[0103] (6) The second magnetic concentrating part with a concave cross-section completely wraps the current row and cooperates with the first magnetic concentrating part projected and overlapped on the Hall sensitive area, so as to form a magnetic flux loop without gap and with larger magnetic concentration range and higher measurement sensitivity;

[0104] (7) The Hall current sensor is suitable for on-chip current measurement of small current (within hundreds of amperes), has high sensing sensitivity, and can further reduce the integrated size and improve the miniaturization and integration degree by using the Hall bare chip array to form the Hall unit.

[0105] Although some embodiments of the present general inventive concept have been shown and described, it would be understood by those of ordinary skill in the art that changes might be made therein without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A Hall current sensor for on-chip current measurement, characterized in that: The Hall current sensor comprises: Two Hall cells, the two Hall cells are arranged in pairs on both sides of the upper surface of the current bank, and each of the two Hall cells is at least one Hall array; a first magnetic concentrating portion, wherein two ends of the first magnetic concentrating portion are respectively arranged on the upper magnetic sensing surfaces of the two Hall units; a second magnetic concentrating portion, the second magnetic concentrating portion having a concave cross-section, the second magnetic concentrating portion wrapping the current row and having two protruding ends respectively disposed on the lower magnetic sensing surfaces of the two Hall elements; The overlapping portion of the projections of the first magnetic focusing portion and the second magnetic focusing portion on the corresponding magnetic sensing surface is located in the Hall sensitive area of ​​the two Hall units; The current magnetic field in the current train is concentrated by the first magnetic concentrator and the second magnetic concentrator to form a magnetic flux loop passing through the Hall sensitive area. The two Hall units sense the current magnetic field and output Hall signals which are then converted into signal outputs proportional to the current in the current train through the Hall circuit.

2. The Hall current sensor according to claim 1, characterized in that: Each of the at least one set of Hall arrays includes at least two Halls arranged side by side; The at least two Hall electrodes are connected in series or in parallel via a signal electrode.

3. The Hall current sensor according to claim 2, characterized in that: The at least two Halls are a group of Hall arrays consisting of cross-shaped Halls, or The at least two Halls are a group of Hall arrays consisting of strip Halls; The total length L of a Hall unit formed by the at least one set of Hall arrays is ≥800 μm.

4. The Hall current sensor according to any one of claims 1 to 3, characterized in that: The cross-shaped Hall element in each Hall unit is a packaged Hall element or a Hall bare chip. The strip Hall in each Hall unit is a packaged strip Hall element or a strip Hall bare chip.

5. The Hall current sensor according to claim 4, characterized in that: Each Hall element is connected in series through the working electrodes to form a differential Hall pair. The output ends of the two Hall units are connected to a signal conditioning circuit arranged on a circuit substrate in a differential series manner.

6. The Hall current sensor according to claim 4 or 5, characterized in that: In the Hall sensitive area of ​​each Hall unit, a length L0 of an overlapping portion of projections of the first magnetic focusing portion and the second magnetic focusing portion on the corresponding magnetic sensing surface is in a range of 0.7-1.0 times the total length L of the corresponding Hall unit.

7. The Hall current sensor according to claim 6, characterized in that: The width W1 of the first magnetic concentrating portion is in the range of 1.5W≤W1≤30W. The width W2 of the second magnetic concentrating portion is in the range of 1.5W≤W2≤30W. W is the width of each Hall element; The width of the second magnetic field focusing portion is greater than the width of the first magnetic field focusing portion.

8. A method for manufacturing a Hall current sensor for on-chip current measurement, wherein the method is used to manufacture the Hall current sensor according to any one of claims 1 to 7, characterized in that: The manufacturing method comprises: Providing a circuit substrate and setting slots penetrating the circuit substrate at positions corresponding to the paired Hall units; Manufacturing two Hall cells in pairs on the circuit substrate, wherein each of the two Hall cells is at least one Hall array; bonding the circuit substrate to the mounting surface of the current bus; Installing a first magnetic concentrator so that both ends of the first magnetic concentrator are respectively arranged on the upper magnetic sensing surfaces of the two Hall units; A second magnetic concentrator having a concave cross-section is installed so that the second magnetic concentrator wraps the current bus and the two protruding ends thereof are inserted into the slots of the circuit substrate and are respectively placed against the lower magnetic sensing surfaces of the two Hall units; Installing a signal conditioning circuit on the circuit substrate and electrically connecting it to the two Hall elements; The current bus, the circuit substrate, the two Hall units, the first magnetic concentrator and the second magnetic concentrator are plastic-sealed and integrated to obtain a Hall current sensor.

9. The manufacturing method according to claim 8, characterized in that The concave cross section of the second magnetic concentrator is in a trapezoidal cross section in the vertical direction. The length of the trapezoidal cross section abutting against the lower magnetic sensing surface of each Hall unit is L1 and L1≤the total length L of the Hall unit. The length of the trapezoidal cross section away from each Hall unit is L2, wherein the length range of L2 is 1.2L1-10L1.

10. The manufacturing method according to claim 9, characterized in that: When the Hall cell in the manufactured Hall current sensor uses a packaged cross-shaped Hall element or a packaged strip-shaped Hall element, The width of the first magnetic concentrating portion at the symmetric center of the two Hall elements is 1.5-6 times the width at both ends thereof; The height of the first magnetic concentrator at the symmetric center of the two Hall elements is 1.2-3 times the height at both ends; The width of the second magnetic concentrating portion at a side away from each Hall unit is 1.5-6 times the width of the second magnetic concentrating portion at a side close to each Hall unit.

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