Hall current sensor for on-chip current measurement and method of manufacturing the same

Abstract

The embodiment of the application 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 arranged in pairs and attached to the two sides of the surface above a current row, each Hall unit being at least one group of Hall arrays; a first magnetic concentrating part is arranged on the upper magnetic induction surface of the two Hall units; a second magnetic concentrating part has a concave cross section and wraps the current row, and the two ends of the second magnetic concentrating part are arranged on the lower magnetic induction surfaces of the two Hall units; the overlapping part of the projection of the first magnetic concentrating part and the second magnetic concentrating part on the corresponding magnetic induction surface is located in the Hall sensitive area of the two Hall units; the current magnetic field 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 area, so that the Hall unit senses the magnetic field and converts the magnetic field into a signal output through a circuit. The Hall current sensor of the application can efficiently concentrate the current magnetic field and avoid the influence of the skin effect on the current measurement.

Description

Technical Field

[0001] This invention relates to the technical field of semiconductor magnetic sensing, and in particular to a Hall current sensor for on-chip current measurement and its manufacturing method. Background Technology

[0002] Hall effect current bus current sensing technology is applicable to a variety of semiconductor sensing fields, and is particularly suitable for detecting small on-chip currents.

[0003] Existing on-chip current Hall sensors place Hall effect sensors on both sides of a current bus to detect the z-axis magnetic field and combine differential calculations to improve gain and reduce interference.

[0004] However, when the frequency of the current in the current busbar changes, such as with variable-frequency DC or periodically changing alternating current, the Hall sensor is affected by the skin effect of the frequency-changing current or magnetic field. In this case, the higher the frequency, the more concentrated the current is on the surface of the current busbar; the lower the frequency, the more concentrated the current is at the center of the current busbar, and the magnetic field distribution also changes accordingly. Under these circumstances, the magnetic flux loop through the Hall sensor and the magnetic field strength that can be sensed through the Hall sensing area will both change. This change leads to unstable sensing performance and significant frequency errors, severely affecting the current detection results.

[0005] In view of this, a novel Hall current sensor for on-chip current measurement and its manufacturing method are proposed to solve all or part of the above problems. Summary of the Invention

[0006] To address at least one of the aforementioned problems and deficiencies in the prior art, embodiments of the present invention provide a Hall current sensor for on-chip current measurement and its manufacturing method, suitable for DC and alternating currents, particularly for sensing the magnetic field of currents in current banks where the current frequency continuously fluctuates. This Hall current sensor achieves efficient magnetic focusing by placing a first magnetic focusing section above and a second magnetic focusing section below a pair of Hall cells arranged horizontally. This ensures that the magnetic flux loop always passes through the Hall sensitive area of ​​the pair of Hall cells with a stable, expected magnetic flux, effectively avoiding the influence of the skin effect of the current caused by frequency changes on the Hall detection signal, thereby significantly reducing frequency errors. Furthermore, the increased magnetic focusing intensity improves the Hall sensing sensitivity. The technical solution is as follows:

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

[0008] Two Hall elements are arranged in pairs on either side of the upper surface of the current busbar, and each of the two Hall elements is at least one Hall array.

[0009] The first magnetic focusing part has its two ends respectively disposed on the upper magnetic induction surface of the two Hall units;

[0010] The second magnetic focusing part has a concave cross section. The second magnetic focusing part wraps the current busbar and its two protruding ends are respectively disposed on the lower magnetic induction surface of the two Hall units.

[0011] The overlapping portion of the projections of the first magnetic focusing part and the second magnetic focusing part onto the corresponding magnetic induction surface is located in the Hall sensitive area of ​​the two Hall units.

[0012] The magnetic field of the current in the current busbar is focused by the first and second magnetic focusing parts to form a magnetic flux loop that passes through the Hall sensitive area. The two Hall units sense the magnetic field of the current and output Hall signals, which are then converted by the Hall circuit into a signal output that is proportional to the current in the current busbar.

[0013] In some embodiments, alternatively, each Hall element is at least one set of Hall arrays, wherein each set of Hall arrays comprises at least two Hall elements arranged side by side. The at least two Hall elements are connected in series or in parallel via signal electrodes.

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

[0015] In some embodiments, alternatively, the Hall element in each Hall cell is a packaged Hall element or a bare Hall chip. The bar Hall element in each Hall cell is a packaged bar Hall element or a bare bar Hall chip.

[0016] In some embodiments, specifically, each Hall unit is connected in series via a working electrode to form a differential Hall pair. The outputs of the two Hall units are connected in differential series to a signal conditioning circuit disposed on a circuit board.

[0017] In some embodiments, preferably, within the Hall sensitive region of each Hall cell, the length L0 of the overlapping portion of the projections of the first magnetic focusing part and the second magnetic focusing part onto the corresponding magnetic induction surface ranges from 0.7 to 1.0 times the total length L of the corresponding Hall cell.

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

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

[0020] A circuit board is provided and slots that penetrate the circuit board are provided at the positions of the Hall units that are arranged in pairs.

[0021] Two pairs of Hall units are fabricated on a circuit board, wherein each Hall unit is at least one set of Hall arrays;

[0022] The circuit board is bonded to the mounting surface of the current bus.

[0023] Install the first magnetic focusing part so that its two ends are respectively placed on the upper magnetic induction surface of the two Hall units;

[0024] The second magnetic core with a concave cross-section is installed to wrap the current busbar, and its two protruding ends are inserted into the slots of the circuit board and respectively attached to the lower magnetic induction surface of the two Hall units.

[0025] A signal conditioning circuit is mounted on the circuit board and electrically connected to two Hall effect units;

[0026] A Hall current sensor is obtained by encapsulating and integrating a current bus, a circuit board, two Hall units, a first magnetic focusing part, and a second magnetic focusing part.

[0027] In some embodiments, specifically, the concave cross section of the second magnetic focusing part has a trapezoidal cross section shape in the vertical direction, the length of the trapezoidal cross section that is attached to the lower magnetic induction surface of each Hall unit is L1 and L1≤ the total length L of the Hall unit, and the length of the trapezoidal cross section that is away from each Hall unit is L2, wherein the length of L2 is in the range of 1.2L1-6L1.

[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 focusing portion at the center of symmetry of the two Hall cells is 1.5-6 times its width at both ends. The height of the first magnetic focusing portion at the center of symmetry of the two Hall cells is 1.2-3 times its height at both ends. The width of the second magnetic focusing portion on the side away from each Hall cell is 1.5-6 times its width on the lower magnetic induction surface abutting each Hall cell.

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

[0030] (1) By setting the first magnetic focusing part and the second magnetic focusing part above and below the paired Hall units arranged in the horizontal direction respectively, efficient magnetic focusing is achieved, so that the magnetic flux loop always passes through the Hall sensitive area of ​​the paired Hall units with a stable expected magnetic flux, effectively avoiding the skin effect of the frequency-changing current, thereby greatly reducing the frequency error and improving the Hall sensing sensitivity.

[0031] (2) By arranging Hall arrays inside paired Hall cells or arranging bar Hall arrays with equivalent lengths and performing series differential, the Hall sensing sensitivity can be further improved and interference reduced.

[0032] (3) In the Hall unit, the Halls can be flexibly arranged in series or parallel by signal electrodes, which can be adapted to various types of on-chip current bus scenarios. The array of cross-shaped Hall or bar Hall effectively improves the gain of the current magnetic field and reduces the influence of different current frequencies on the detection of the magnetic field.

[0033] (4) By combining the overall size ratio of the Hall unit pair to design the relative width of the first magnetic concentrating part and the second magnetic concentrating part, 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 focusing part to be wider and longer at the bottom away from the Hall and gradually decreasing 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 paired Hall units.

[0035] (6) The second magnetic focusing part with a concave cross section completely wraps the current busbar and, together with the first magnetic focusing part projected and superimposed on the Hall sensitive area, can form a gapless magnetic flux loop with a larger magnetic focusing range and higher measurement sensitivity.

[0036] (7) The Hall current sensor is suitable for on-chip current measurement of small current (within 100 amperes), has high sensing sensitivity, and can further reduce the integration size and improve miniaturization and integration by using Hall bare chip array to form Hall units. Attached Figure Description

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

[0038] Figure 1 This is a schematic cross-sectional view of a Hall current sensor for on-chip current measurement according to Embodiment 1 of the present invention;

[0039] Figure 2 for Figure 1 A top view of the structure of the Hall current sensor shown;

[0040] Figure 3 This is a schematic diagram of a Hall cell structure in a Hall current sensor according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of yet another structure of the Hall cell in a Hall current sensor according to an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of a connection structure of a pair of Hall units in a Hall current sensor according to an embodiment of the present invention;

[0043] Figure 6 This is a schematic cross-sectional view of a Hall current sensor for on-chip current measurement according to Embodiment 2 of the present invention;

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

[0045] Figure 8 This is a flowchart illustrating a method for manufacturing a Hall current sensor for on-chip current measurement according to an embodiment of the present invention. Detailed Implementation

[0046] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof.

[0047] It should also be understood that although the terms "first," "second," "third," etc., may be used in the following embodiments of the present invention to describe a component comprising two or more of the same component, these components should not be limited to these terms, which are only used to distinguish each component from one another. Furthermore, descriptions indicating orientation such as "upper," "lower," "left," and "right" are merely illustrative of the relative positions of components and should not be construed as a limitation of the present invention.

[0048] The Hall current sensor for on-chip current measurement and its manufacturing method provided by the embodiments of the present invention achieve efficient magnetic focusing by setting a first magnetic focusing part and a second magnetic focusing part above and below the paired Hall units arranged in the horizontal direction, respectively. This ensures that the magnetic flux loop always passes through the Hall sensitive area of ​​the paired Hall units with a stable expected magnetic flux, effectively avoiding the influence of the skin effect of frequency-changing current on current measurement, thereby significantly reducing frequency error and improving Hall sensing sensitivity.

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

[0050] Example 1

[0051] See Figure 1 The overall cross-sectional structure of the Hall current sensor 100 for on-chip current measurement according to Embodiment 1 is shown. See also... Figure 2 , showed Figure 1 A top view of the overall structure of the Hall current sensor 100.

[0052] Combination Figure 1 and Figure 2 As shown, the Hall current sensor 100 is mainly composed of a pair of Hall units (first Hall unit 11 and second Hall unit 12) arranged horizontally on the upper surface of the current bus 200, a first magnetic focusing part 20 above, a second magnetic focusing part 30 with a concave cross section below, and a circuit board 40.

[0053] The first Hall element 11 and the second Hall element 12 are arranged in pairs abutting each other on both sides of the upper surface of the current bus 200, and each of the two Hall elements is at least one Hall array (e.g., Figure 3 or Figure 4 The cross-shaped Hall array shown, for example Figure 5 The bar Hall array shown.

[0054] The first magnetic focusing part 20 has its two ends respectively disposed on the upper magnetic induction surface of the first Hall unit 11 and the second Hall unit 12;

[0055] The second magnetic focusing part 30 has a concave cross section. The second magnetic focusing part 30 completely encloses the current bus 200 and its two protruding ends are respectively disposed on the lower magnetic induction surface of the first Hall unit 11 and the second Hall unit 12.

[0056] The overlapping portion of the projections of the first magnetic focusing part 20 and the second magnetic focusing part 30 onto the corresponding magnetic induction surface is located in the Hall sensitive area of ​​the first Hall unit 11 and the second Hall unit 12.

[0057] The magnetic field of the current in the current busbar 200 is focused by the first magnetic focusing part 20 and the second magnetic focusing part 30 to form a magnetic flux loop that passes through the Hall sensitive area. The two Hall units (the first Hall unit 11 and the second Hall unit 12) sense the magnetic field of the current and output Hall signals, which are then converted into a signal output that is proportional to the current in the current busbar 200 by the Hall circuit in the circuit board 40.

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

[0059] See Figure 3 The diagram illustrates the specific structure of a Hall unit (taking the first Hall unit 11 as an example) in one embodiment, wherein several Hall units (cross-shaped Hall units) are connected in parallel to form the first Hall unit 11.

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

[0061] See Figure 4 The diagram illustrates the specific structure of a Hall unit (taking the first Hall unit 11' as an example) in another embodiment, wherein a plurality of Hall units (cross-shaped Hall units) are connected in series to form the first Hall unit 11'.

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

[0063] For example, Figure 3 and Figure 4A connection structure in which three Hall effect sensors (Hall A, Hall B, and Hall C) are connected in series is given. The number of Hall effect sensors in the array can be two, three, or more. Furthermore, one, two, three, or more sets of the aforementioned Hall effect arrays can be arranged, for example, in the first Hall effect unit 11. This example is merely illustrative and should not be construed as limiting the invention by those skilled in the art.

[0064] In one example, alternatively, a Hall array can also be composed of bar Hall elements within a group of Hall elements of a Hall cell. 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 is illustrated. The arrangement and electrical connection of at least two bar Hall units can be referred to the embodiment using cross-shaped Hall units described above, and will not be repeated here.

[0065] In one example, preferably, the total length L of a Hall unit composed of at least one set of Hall arrays is ≥800μm, and more preferably, the total length L is ≥1mm.

[0066] In the overall structure of the Hall current sensor 100, in order to form a stable magnetic flux loop unaffected by fluctuations or changes in current frequency, the total length L of the Hall unit needs to be designed in coordination with the structural dimensions of the first magnetic focusing part 20 and the second magnetic focusing part 30 to have a certain length value. When the current frequency changes, causing the magnetic field lines to expand outward or contract inward, a relatively fixed magnetic flux can be maintained through the magnetic induction sensitive area of ​​the Hall unit, thereby realizing that Hall sensing is no longer affected by the current frequency (skin effect) and has a stable magnetic flux.

[0067] See Figure 5 The diagram illustrates a series differential structure of a pair of Hall units (first Hall unit 11 and second Hall unit 12) in one embodiment.

[0068] Combination Figures 3-5 As shown, in one example, specifically, the first Hall unit 11 and the second Hall unit 12 are connected in series via electrodes to form a differential Hall pair. For example, the second working electrode a2 of the first Hall unit 11 is connected in series with the first working electrode b1 of the second Hall unit 12, and their signal electrodes are also connected in series sequentially. The output terminals of the paired 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 differential series to a signal conditioning circuit 42 disposed on the circuit board 40 (e.g., Figure 2 (as shown in the circuit board).

[0069] In one example, preferably, within the Hall-sensitive region of each Hall cell (e.g., the first Hall cell 11), the length L0 of the overlapping portion of the projections of the first magnetic focusing part 20 and the second magnetic focusing part 30 onto the corresponding magnetic induction surface is 0.7-1.0 times the total length L of the first Hall cell 11. Simultaneously, when designing the specific structure and dimensions of the two magnetic focusing parts, it is necessary to ensure, on the one hand, that the magnetic focusing 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 within the Hall-sensitive region of this Hall cell and does not extend beyond it.

[0070] like Figure 1 As shown, in one example, preferably, the second magnetic focusing part 30 is generally trapezoidal with a wide bottom and has a concave cavity in the center to form a concave cross section.

[0071] The portion in the vertical direction has a trapezoidal cross-section. The length of the trapezoidal cross-section abutting the lower magnetic induction surface of each Hall cell is L1, and L1 is less than or equal to the total length L of the Hall cell. In other words, the length of the trapezoidal cross-section here is within the total length of the Hall cell, thus ensuring that the magnetic field converged by the second magnetic focusing section 30 completely passes through the Hall cell at that location. Even if the current frequency changes, causing the magnetic field to expand outward or contract inward, the Hall cell can still obtain the expected and stable magnetic flux to maintain the expected and stable magnetic focusing intensity.

[0072] Away from each Hall unit ( Figure 1 The length of the trapezoidal cross section of the bottom of the Hall current sensor 100 is L2, wherein the length of L2 ranges from 1.2L1 to 10L1, and more preferably, the length of L2 ranges from 1.5L1 to 6L1.

[0073] like Figure 2 As shown, in one example, preferably, the width W1 of the first magnetic focusing part 20 is in the range of 1.5W ≤ W1 ≤ 30W, and the width W2 of the second magnetic focusing part 30 is in the range of 1.5W ≤ W2 ≤ 30W, where W is the width of each Hall unit (e.g., the first Hall unit 11). Furthermore, the width of the second magnetic focusing part 30 is greater than the width of the first magnetic focusing part 20.

[0074] exist Figure 1The diagram exemplarily illustrates the magnetic flux loop corresponding to a change in the frequency of the current in the current busbar 200. When a magnetic field of different frequencies is sensed, regardless of the changes in the current and magnetic field frequencies, the magnetic field lines can concentrate and pass through the Hall sensitive areas of the paired Hall units (first Hall unit 11 and second Hall unit 12). Furthermore, regardless of whether the Hall units within each unit are connected in parallel or series, their output signal is the superposition or average of the sensing signals of these Hall units. Changes in the magnetic field distribution do not affect the structure of the final Hall signal. Therefore, the skin effect caused by the change in current frequency makes the change in the magnetic field distribution on the Hall signal negligible. Simultaneously, since the upper and lower magnetic focusing structures completely enclose the current busbar 200 and the paired Hall units, sensitivity is further enhanced. When the Hall current sensor 100 detects current, the magnetic flux loop has almost no gaps and completely passes through the Hall sensitive areas of the Hall units, with a larger magnetic focusing range, resulting in a significant improvement in measurement sensitivity compared to existing Hall sensors.

[0075] In one example, alternatively, the Hall element in each Hall cell can be a packaged Hall element (i.e., electrically connected via metal pins outside the package structure after integration) or a bare Hall chip (i.e., an unpackaged structure that can be electrically connected via circuit wiring or metal wire bonding). Similarly, a cross-shaped Hall element (packaged or bare chip form) or a bar-shaped Hall element (packaged or bare chip form) can be used in each Hall cell.

[0076] In Embodiment 1 above, a cross-shaped Hall bare chip or a strip-shaped Hall bare chip is preferably used. Embodiment 2 below focuses on the matching arrangement of the upper and lower magnetic focusing parts when using a packaged cross-shaped Hall element or a packaged strip Hall element.

[0077] Example 2

[0078] See Figure 6 The overall cross-sectional structure of the Hall current sensor 100a for on-chip current measurement according to Embodiment 2 is shown. See also... Figure 7 , showed Figure 7 A top view of the overall structure of the Hall current sensor 100a.

[0079] Combination Figure 6 and Figure 7 As shown, the Hall current sensor 100a is mainly composed of a pair of Hall units (first Hall unit 11a and second Hall unit 12a) arranged horizontally on the upper surface of the current busbar 200, a first magnetic focusing part 20a disposed above the two Hall units, a second magnetic focusing part 30a with a concave cross section below, and a circuit board 40a.

[0080] For packaged Hall effect devices, the presence of a package and lead electrodes results in a larger overall size compared to bare Hall effect chips. Therefore, packaged Hall effect devices require a larger, split-type magnetic focusing structure. Furthermore, to effectively concentrate the magnetic field, the cross-sectional shape of the magnetic focusing structure is more complex; for example, a gradient cross-sectional structure needs to be designed in both height and width to concentrate more current and magnetic field, thereby improving sensitivity.

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

[0082] The width W of the first magnetic focusing section 20a at the center of symmetry of the two Hall units 1a It is its width W at both ends 1b 1.5-6 times that.

[0083] The first magnetic focusing section 20a is located at a height H of the center of symmetry between the two Hall units. 1a It is its height H at both ends 1b 1.2-3 times that.

[0084] The second magnetic focusing part 30a is located on the side away from each Hall unit (i.e.) Figure 6 The width W of the bottom of the Hall current sensor 100a shown 2a It is the width W of the lower magnetic induction surface that is attached to each Hall element. 2b 1.5-6 times 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. This method is used to manufacture the Hall current sensors (e.g., Hall current sensor 100, Hall current sensor 100a) described in the above embodiments. See also... Figure 8 Taking the Hall current sensor 100 of Embodiment 1 as an example, the specific steps of this manufacturing method include:

[0086] Step 301: Provide a circuit board 40 (including a substrate 41) and provide slots through the circuit board 40 at the positions of the corresponding pairs of Hall units (first Hall unit 11 and second Hall unit 12).

[0087] Step 302: Fabricate a pair of Hall units (first Hall unit 11 and second Hall unit 12) on the circuit board 40, wherein each Hall unit is at least one set of Hall arrays;

[0088] Step 303: Bond the circuit board 40 onto the mounting surface of the current bus 200;

[0089] Step 304: Install the first magnetic focusing part 20 so that its two ends are respectively placed on the upper magnetic induction surface of the two Hall units;

[0090] Step 305: Install the second magnetic focusing part 30 with a concave cross section to wrap around the current bus 200 and insert its two protruding ends into the slots of the circuit board 40 and respectively abut against the lower magnetic induction surface of the two Hall units.

[0091] Step 306: Install the signal conditioning circuit 42 on the circuit board 40 and electrically connect it to the two Hall effect units;

[0092] Step 307: The Hall current sensor 100 is obtained by plastic encapsulating and integrating the current bus 200, the circuit board 40, the two Hall units (the first Hall unit 11 and the second Hall unit 12), the first magnetic focusing part 20 and the second magnetic focusing part 30.

[0093] exist Figure 2 As can be seen, after packaging in step 307, the circuit board 40 includes a substrate 41, a signal conditioning circuit 42, and pin electrodes 43.

[0094] exist Figure 7 As can be seen, if a pre-packaged Hall element is used in the Hall cell, since it already contains signal conditioning circuits or signal conversion circuits, the circuit board 40a already integrates all the integrated circuits 41a for the Hall current sensor 100a to sense and output the current measurement value. After overall packaging, the overall pin electrodes 43a are then set on the outside of the package.

[0095] The cross-sectional shape and dimensions of the upper and lower magnetic focusing structures can be set with reference to the preferred parameters in Embodiments 1 and 2 above. Meanwhile, those skilled in the art will understand that the design of the preferred or specific magnetic focusing structure needs to be matched to the actual on-chip current bus scenario and measurement requirements. Only some illustrative examples are provided here, and those skilled in the art should not construe them as a limitation of the present invention.

[0096] This manufacturing method creates slots on the circuit board 40 to fix the second magnetic focusing part 30, which, together with the first magnetic focusing part 20, encloses the current bus 200 and the paired Hall cells (first Hall cell 11 and second Hall cell 12) to form a through-type magnetic focusing structure. This allows the current in the current bus to form a stable magnetic focusing loop in the magnetically sensitive area of ​​the Hall cell pair when passing through this through-type magnetic focusing structure. Simultaneously, it effectively concentrates the magnetic field, achieving high sensing sensitivity within a small on-chip space and resisting the skin effect of current on Hall sensing.

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

[0098] (1) By setting the first magnetic focusing part and the second magnetic focusing part above and below the paired Hall units arranged in the horizontal direction respectively, efficient magnetic focusing is achieved, so that the magnetic flux loop always passes through the Hall sensitive area of ​​the paired Hall units with a stable expected magnetic flux, effectively avoiding the skin effect of the frequency-changing current, thereby greatly reducing the frequency error and improving the Hall sensing sensitivity.

[0099] (2) By arranging Hall arrays inside paired Hall cells or arranging bar Hall arrays with equivalent lengths and performing series differential, the Hall sensing sensitivity can be further improved and interference reduced.

[0100] (3) In the Hall unit, the Halls can be flexibly arranged in series or parallel by signal electrodes, which can be adapted to various types of on-chip current bus scenarios. The array of cross-shaped Hall or bar Hall effectively improves the gain of the current magnetic field and reduces the influence of different current frequencies on the detection of the magnetic field.

[0101] (4) By combining the overall size ratio of the Hall unit pair to design the relative width of the first magnetic concentrating part and the second magnetic concentrating part, an effective and stable magnetic flux loop can be formed, thereby realizing the concentration and stable convergence of the current magnetic field;

[0102] (5) By setting the second magnetic focusing part to be wider and longer at the bottom away from the Hall and gradually decreasing 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 paired Hall units.

[0103] (6) The second magnetic focusing part with a concave cross section completely wraps the current busbar and, together with the first magnetic focusing part projected and superimposed on the Hall sensitive area, can form a gapless magnetic flux loop with a larger magnetic focusing range and higher measurement sensitivity.

[0104] (7) The Hall current sensor is suitable for on-chip current measurement of small current (within 100 amperes), has high sensing sensitivity, and can further reduce the integration size and improve miniaturization and integration by using Hall bare chip array to form Hall units.

[0105] While some embodiments of the present general inventive concept have been shown and described, those skilled in the art will understand that changes may be made to these embodiments 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 includes: Two Hall elements are arranged in pairs on both sides of the upper surface of the current busbar, and each of the two Hall elements is at least one Hall array. The first magnetic focusing part has its two ends respectively disposed on the upper magnetic induction surface of the two Hall units; The second magnetic focusing part has a concave cross section, and the second magnetic focusing part wraps around the current busbar and its two protruding ends are respectively disposed on the lower magnetic induction surface of the two Hall units; The overlapping portion of the projections of the first magnetic focusing part and the second magnetic focusing part onto the corresponding magnetic induction surface is located in the Hall sensitive area of ​​the two Hall units; The magnetic field of the current in the current bank is focused by the first and second magnetic focusing parts to form a magnetic flux loop that passes through the Hall sensitive area. The two Hall units sense the magnetic field of the current and output Hall signals, which are then converted by the Hall circuit into a signal output that is proportional to the current in the current bank.

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 Hall arrays arranged side by side; The at least two Hall effect sensors are connected in series or in parallel via signal electrodes.

3. The Hall current sensor according to claim 2, characterized in that, The at least two Hall elements are a Hall array consisting of cross-shaped Hall elements, or The at least two Hall elements are a Hall array composed of bar Hall elements; The total length L of a Hall unit composed of at least one set of Hall arrays is ≥800μm.

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

5. The Hall current sensor according to claim 4, characterized in that, Each Hall unit is connected in series via a working electrode to form a differential Hall pair. The output terminals of the two Hall units are connected in differential series to a signal conditioning circuit mounted on the circuit board.

6. The Hall current sensor according to claim 4 or 5, characterized in that, Within the Hall-sensitive region of each Hall cell, the length L0 of the overlapping portion of the projections of the first magnetic focusing part and the second magnetic focusing part onto the corresponding magnetic induction surface ranges from 0.7 to 1.0 times the total length L of the corresponding Hall cell.

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

8. A method for manufacturing a Hall current sensor for on-chip current measurement, the method being used to manufacture a Hall current sensor according to any one of claims 1-7, characterized in that, The manufacturing method includes: A circuit board is provided and slots that penetrate the circuit board are provided at the positions of the Hall units that are arranged in pairs. Two Hall units are fabricated on the circuit board, and each of the two Hall units is at least one set of Hall arrays; The circuit board is bonded to the mounting surface of the current bus. Install the first magnetic focusing part so that its two ends are respectively placed on the upper magnetic induction surface of the two Hall units; A second magnetic focusing part with a concave cross-section is installed so that the second magnetic focusing part wraps around the current busbar and its two protruding ends are inserted into the slots of the circuit board and respectively abut against the lower magnetic induction surface of the two Hall units. A signal conditioning circuit is mounted on the circuit board and electrically connected to the two Hall effect units. A Hall current sensor is obtained by encapsulating and integrating the current bus, the circuit board, the two Hall cells, the first magnetic focusing part, and the second magnetic focusing part.

9. The manufacturing method according to claim 8, characterized in that, The concave cross-section of the second magnetizing part has a trapezoidal cross-section shape in the vertical direction. The length of the trapezoidal cross-section abutting the lower magnetic induction surface of each Hall element is L1, and L1 ≤ the total length L of the Hall element. The length of the trapezoidal cross section away from each Hall unit is L2, where the length of L2 ranges from 1.2L1 to 10L1.

10. The manufacturing method according to claim 9, characterized in that, When the Hall element 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 focusing part at the center of symmetry of the two Hall units is 1.5-6 times its width at both ends; The height of the first magnetic focusing part at the center of symmetry of the two Hall units is 1.2-3 times its height at both ends; The width of the second magnetic focusing part on the side away from each Hall cell is 1.5-6 times the width of its lower magnetic induction surface that is attached to each Hall cell.

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