Pad structure and printed circuit board
By designing a spaced-out pad structure, the influence of welding impedance is eliminated, and only the voltage across the current sensing resistor is measured. This solves the problem of low accuracy in current detection in traditional technologies and achieves high-precision current sampling.
Patent Information
- Application Number
- CN202520278885.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2035-02-20
AI Technical Summary
In traditional techniques, when welding resistors are on printed circuit boards, the welding impedance leads to low accuracy in current value detection.
Design a pad structure including a first pad group and a second pad group arranged at intervals. A current sensing resistor is connected through the first pad and the third pad, and a sampling line is connected through the second pad and the fourth pad to eliminate the influence of soldering impedance and measure only the voltage across the current sensing resistor.
It improves the accuracy of current detection, reduces errors caused by wiring and contact resistance, is suitable for Kelvin detection, and improves the accuracy of current sampling.
Smart Images
Figure CN223772227U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of electronic communication technology, and in particular to a pad structure and a printed circuit board. Background Technology
[0002] With the development and advancement of science and technology, electronic devices are being used more and more. In electronic devices, it is often necessary to detect the current in the circuit, for purposes such as fuel gauges and charging management. The common method for obtaining the current is to connect a high-precision resistor in series in the circuit, detect the voltage difference across the resistor, and divide the voltage difference by the resistance value to obtain the current value in the circuit.
[0003] In traditional technology, high-precision resistors are soldered onto printed circuit boards using surface mount technology. However, when soldering resistors onto pads on the PCB using traditional technology, in addition to the resistance value of the resistor itself, there is also soldering impedance between the resistor and the PCB, which results in lower accuracy of the detected current value. Utility Model Content
[0004] This disclosure provides a pad structure and a printed circuit board to address the shortcomings of related technologies.
[0005] In a first aspect, embodiments of this disclosure provide a pad structure for a current-sensing resistor, comprising: a first pad group and a second pad group spaced apart, the first pad group including a first pad and a second pad spaced apart from the first pad, the second pad group including a third pad and a fourth pad spaced apart from the third pad; the first pad and the third pad are used to conduct the current-sensing resistor, the second pad is provided with a first detection point for connecting a sampling line, and the fourth pad is provided with a second detection point for connecting a sampling line.
[0006] Optionally, the first pad group and the second pad group are spaced apart along a first direction, the first pad and the second pad are spaced apart along a second direction, and the third pad and the fourth pad are spaced apart along the second direction, wherein the second direction is perpendicular to the first direction.
[0007] Optionally, the first pad and the third pad are spaced apart along the first direction, and the second pad and the fourth pad are spaced apart along the first direction.
[0008] Optionally, the spacing between the first pad and the third pad is equal to the spacing between the second pad and the fourth pad; and / or
[0009] The spacing between the first pad and the second pad is equal to the spacing between the third pad and the fourth pad.
[0010] Optionally, the area of the first pad is equal to the area of the third pad, and the first pad and the third pad are arranged symmetrically along an axis parallel to the second direction; and / or
[0011] The area of the second pad is equal to the area of the fourth pad, and the second pad and the fourth pad are arranged symmetrically along an axis parallel to the second direction.
[0012] Optionally, the first detection point and the second detection point are arranged symmetrically along an axis parallel to the second direction.
[0013] Optionally, the first detection point is located on the side of the second pad close to the fourth pad, and the second detection point is located on the side of the fourth pad close to the second pad.
[0014] Optionally, the first pad group and the second pad group are spaced apart along a first direction, the first pad and the second pad are spaced apart along the first direction, and the third pad and the fourth pad are spaced apart along the first direction.
[0015] Optionally, the second pad and the fourth pad are located between the first pad and the third pad.
[0016] Optionally, the spacing between the first pad and the second pad is equal to the spacing between the third pad and the fourth pad.
[0017] Optionally, the area of the first pad is equal to the area of the third pad, the first pad and the third pad are symmetrically arranged along an axis parallel to the second direction, and the second direction is perpendicular to the first direction; and / or
[0018] The area of the second pad is equal to the area of the fourth pad. The second pad and the fourth pad are arranged symmetrically along an axis parallel to the second direction, which is perpendicular to the first direction.
[0019] Optionally, the first detection point and the second detection point are arranged symmetrically along an axis parallel to the second direction, and the second direction is perpendicular to the first direction.
[0020] Optionally, the first detection point is located on one side of the second pad along the second direction, and the second detection point is located on the same side of the fourth pad along the second direction.
[0021] Optionally, both the first detection point and the second detection point are vias; and / or
[0022] The area of the first pad is larger than the area of the second pad; and / or
[0023] The area of the third pad is larger than the area of the fourth pad.
[0024] In a second aspect, embodiments of this disclosure provide a printed circuit board, including a board body and a pad structure as described in the first aspect, the pad structure being disposed on the board body.
[0025] Optionally, a current sensing resistor is also included, which is soldered to the first pad, the second pad, the third pad, and the fourth pad.
[0026] Optionally, it also includes a first sampling line and a second sampling line disposed on the plate, wherein the first sampling line is connected to the first detection point and the second sampling line is connected to the second detection point.
[0027] Optionally, the first pad group and the second pad group are spaced apart along a first direction, and the first sampling line and the second sampling line are symmetrically arranged along an axis parallel to a second direction, wherein the second direction is perpendicular to the first direction.
[0028] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:
[0029] As can be seen from the above embodiments, the pad structure of this disclosure uses the first and third pads to conduct the current sensing resistor, and the second and fourth pads to connect the sampling line to detect the voltage drop across the current sensing resistor. When measuring the voltage across the current sensing resistor, since the current through the second and fourth pads is very small, the soldering impedance between the current sensing resistor and the printed circuit board is eliminated. This means that only the voltage across the current sensing resistor is measured through the sampling line, and the resistance value in the circuit is almost the same as the resistance value of the current sensing resistor, thus improving the accuracy of the current detection.
[0030] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description
[0031] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.
[0032] Figure 1 This is a schematic diagram illustrating a pad structure according to an exemplary embodiment.
[0033] Figure 2 This is a schematic diagram of a pad structure according to another exemplary embodiment. Detailed Implementation
[0034] The technical solutions in the embodiments (or "implementations") of this application will be clearly and completely described herein with reference to the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.
[0035] If the embodiments of this application contain terms relating to directional indications or positional relationships (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationships and movements between components in a specific posture (as shown in the attached figures); if the specific posture changes, the directional indications or positional relationships will also change accordingly. Furthermore, the terms "first" and "second" used in the embodiments of this application are only for descriptive convenience and should not be construed as indicating or implying relative importance.
[0036] To facilitate understanding of the technical solutions of this disclosure, the pad structure and printed circuit board of this disclosure will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementations can be combined with each other.
[0037] See Figure 1 and Figure 2 As shown, this embodiment of the present disclosure provides a pad structure 100 for a current sensing resistor, including: a first pad group 10 and a second pad group 20 spaced apart, the first pad group 10 including a first pad 11 and a second pad 12 spaced apart from the first pad 11, the second pad group 20 including a third pad 21 and a fourth pad 22 spaced apart from the third pad 21; the first pad 11 and the third pad 21 are used to conduct the current sensing resistor, the second pad 12 is provided with a first detection point 13 for connecting a sampling line, and the fourth pad 22 is provided with a second detection point 23 for connecting a sampling line.
[0038] As can be seen from the above embodiments, the pad structure 100 of this disclosure divides the first pad group 10 into a first pad 11 and a second pad 12. The first pad 11 and the third pad 21 are used to conduct the current sensing resistor, and the second pad 12 and the fourth pad 22 are used to connect the sampling line to detect the voltage drop of the current sensing resistor. That is, the first pad 11 and the third pad 21 are responsible for the flow of current (the current direction is shown by the arrow in the figure), and the copper pouring and vias required for the routing are all performed on the first pad 11 and the third pad 21. The second pad 12 and the fourth pad 22 are responsible for the sampling line output. It can be understood that the first pad 11 and the third pad 21 can be regarded as current-carrying pads, and the second pad 12 and the fourth pad 22 can be regarded as current-sensing pads.
[0039] When measuring the voltage across the current sensing resistor, the current through the second pad 12 and the fourth pad 22 is very small, eliminating the soldering impedance between the current sensing resistor and the printed circuit board. This means that only the voltage across the current sensing resistor is measured through the sampling line, and the resistance value in the circuit is almost the same as that of the current sensing resistor. This method is suitable for Kelvin detection, using separate current and voltage detection, eliminating the impedance of wiring and contact resistance, reducing errors caused by solder resistivity, and improving the sampling accuracy of the detection current.
[0040] In some optional embodiments, the area of the first pad 11 is larger than the area of the second pad 12. The area of the third pad 21 is larger than the area of the fourth pad 22. Since the first pad 11 and the third pad 21 are used to conduct the current sensing resistor and are responsible for the flow of current, their areas are larger than those of the second pad 12 and the fourth pad 22. It should be noted that the sizes of the first pad 11, the second pad 12, the third pad 21, and the fourth pad 22 can be determined according to the size of the current sensing resistor, and this disclosure does not impose any limitations on this.
[0041] In some alternative implementations, such as Figure 1 The diagram illustrates one pad layout. The first pad group 10 and the second pad group 20 are spaced apart along a first direction X; the first pad 11 and the second pad 12 are spaced apart along a second direction Y; and the third pad 21 and the fourth pad 22 are spaced apart along the second direction Y, which is perpendicular to the first direction X. This spacing between the first pad 11 and the second pad 12 prevents them from being soldered together when the current-sensing resistor is soldered to the first pad group 10. Similarly, the spacing between the third pad 21 and the fourth pad 22 prevents them from being soldered together when the current-sensing resistor is soldered to the second pad group 20.
[0042] In some optional embodiments, the first pad 11 and the third pad 21 are spaced apart along the first direction X, and the second pad 12 and the fourth pad 22 are spaced apart along the first direction X. That is, the second pad 12 and the fourth pad 22 are located on the same side of the first pad 11 and the third pad 21. This arrangement makes the layout of the pads more compact and occupies less space. Optionally, the spacing between the first pad 11 and the third pad 21 is equal to the spacing between the second pad 12 and the fourth pad 22. The spacing between the first pad 11 and the second pad 12 is equal to the spacing between the third pad 21 and the fourth pad 22. This makes the layout of the first pad group 10 and the second pad group 20 more regular.
[0043] Furthermore, the area of the first pad 11 is equal to the area of the third pad 21, and the first pad 11 and the third pad 21 are symmetrically arranged along an axis 80 parallel to the second direction Y. The area of the second pad 12 is equal to the area of the fourth pad 22, and the second pad 12 and the fourth pad 22 are symmetrically arranged along an axis 80 parallel to the second direction Y. This arrangement makes the layout of the first pad group 10 and the second pad group 20 more regular and orderly, reduces the error caused by the solder resistive resistor, and improves the sampling accuracy. It also avoids the situation where one end is not soldered when soldering the current sensing resistor, thereby improving the practicality of the pad structure 100.
[0044] In some optional embodiments, the first detection point 13 and the second detection point 23 are symmetrically arranged along an axis 80 parallel to the second direction Y to ensure symmetrical routing of the second pad 12 and the fourth pad 22. It should be noted that both the first detection point 13 and the second detection point 23 can be conductive connection structures. Alternatively, when the second pad 12 and the fourth pad 22 need to be routed on different layers, both the first detection point 13 and the second detection point 23 can be vias, and the vias should be symmetrical as much as possible to ensure symmetrical routing of the second pad 12 and the fourth pad 22.
[0045] In this embodiment, the first detection point 13 is located on the side of the second pad 12 closest to the fourth pad 22, and the second detection point 23 is located on the side of the fourth pad 22 closest to the second pad 12. This allows the sampling lines connected to the second pad 12 and the fourth pad 22 to be closer together, reducing errors caused by solder resist and improving sampling accuracy.
[0046] In some alternative implementations, such as Figure 2 The diagram shows another layout of the pads. The first pad group 10 and the second pad group 20 are spaced apart along the first direction X; the first pad 11 and the second pad 12 are spaced apart along the first direction X; and the third pad 21 and the fourth pad 22 are spaced apart along the first direction X. This spacing between the first pad 11 and the second pad 12 prevents them from being soldered together when the current-sensing resistor is soldered to the first pad group 10. Similarly, the spacing between the third pad 21 and the fourth pad 22 prevents them from being soldered together when the current-sensing resistor is soldered to the second pad group 20.
[0047] In some optional embodiments, the second pad 12 and the fourth pad 22 are located between the first pad 11 and the third pad 21. Thus, the first pad 11 and the third pad 21 are located on the outside for current flow. This arrangement also allows the sampling lines connected to the second pad 12 and the fourth pad 22 to be closer together, reducing errors caused by solder resist and improving sampling accuracy. Furthermore, this arrangement results in a more compact layout of the pads, occupying less space. Optionally, the spacing between the first pad 11 and the second pad 12 is equal to the spacing between the third pad 21 and the fourth pad 22. This makes the layout of the first pad group 10 and the second pad group 20 more regular.
[0048] Furthermore, the area of the first pad 11 is equal to the area of the third pad 21. The first pad 11 and the third pad 21 are symmetrically arranged along an axis 80 parallel to the second direction Y, which is perpendicular to the first direction X. The area of the second pad 12 is equal to the area of the fourth pad 22. The second pad 12 and the fourth pad 22 are symmetrically arranged along an axis 80 parallel to the second direction Y, which is perpendicular to the first direction X. This arrangement makes the layout of the first pad group 10 and the second pad group 20 more regular and orderly, reduces the error caused by the solder resistive resistor, and improves the sampling accuracy. It also avoids the situation where one end is not soldered when soldering the current sensing resistor, thereby improving the practicality of the pad structure 100.
[0049] In some optional embodiments, the first detection point 13 and the second detection point 23 are symmetrically arranged along an axis 80 parallel to the second direction Y, which is perpendicular to the first direction X. This ensures symmetrical routing of the second pad 12 and the fourth pad 22. It should be noted that both the first detection point 13 and the second detection point 23 can be conductive connection structures. Alternatively, when the second pad 12 and the fourth pad 22 need to be routed on different layers, both the first detection point 13 and the second detection point 23 can be vias, and the vias should be symmetrical as much as possible to ensure symmetrical routing of the second pad 12 and the fourth pad 22.
[0050] Optionally, the first detection point 13 is located on one side of the second pad 12 along the second direction Y, and the second detection point 23 is located on the same side of the fourth pad 22 along the second direction Y. Figure 2 In the illustrated embodiment, the first detection point 13 is located at the bottom end of the second pad 12 along the second direction Y, and the second detection point 23 is located at the bottom end of the fourth pad 22 along the second direction Y. That is, both the second pad 12 and the fourth pad 22 have traces extending from the bottom side. Of course, in other examples, both the second pad 12 and the fourth pad 22 may have traces extending from the top side, and this disclosure does not limit this.
[0051] This disclosure also provides a printed circuit board, including a board body, a current sensing resistor, and a pad structure 100 as described in the above embodiments and implementations, the pad structure 100 being disposed on the board body. Figure 1 and Figure 2 As shown, the current sensing resistor corresponds to region 90 and is soldered to the first pad 11, the second pad 12, the third pad 21, and the fourth pad 22. Region 90 can be understood as the area on the board used for soldering the current sensing resistor.
[0052] The printed circuit board may further include a first sampling line 31 and a second sampling line 32 disposed on the board body. The first sampling line 31 is connected to the first detection point 13, and the second sampling line 32 is connected to the second detection point 23. The first sampling line 31 and the second sampling line 32 are used to connect to an external detection component to measure the voltage of the current sensing resistor. This is convenient and simple to use, improving the practicality of the pad structure 100. The routing method of the first sampling line 31 and the second sampling line 32 can be a serpentine routing method or a Kelvin routing method. This embodiment does not impose any restrictions on this, as long as its function can be achieved.
[0053] Optionally, the first pad group 10 and the second pad group 20 are spaced apart along a first direction X, and the first sampling line 31 and the second sampling line 32 are symmetrically arranged along an axis 80 parallel to a second direction Y, which is perpendicular to the first direction X. This arrangement makes the layout of the first pad group 10 and the second pad group 20 more regular and orderly, reduces the error caused by the solder resist, and improves the sampling accuracy. It also avoids the situation where one end is not soldered when soldering the current sensing resistor, thereby improving the practicality of the pad structure 100.
[0054] The current detection process of the printed circuit board in this embodiment is as follows:
[0055] A current-sensing resistor is soldered from region 90 to the first pad 11, the second pad 12, the third pad 21, and the fourth pad 22. The first sampling line 31 and the second sampling line 32 are connected to an external detection component, forming a loop with the second pad 12, the first sampling line 31, the detection component, the fourth pad 22, and the second sampling line 32, to measure the voltage across the current-sensing resistor. Due to the high impedance of the external detection component, the current through the second pad 12 and the fourth pad 22 is very small, almost zero. The detection component is also electrically connected to the current-sensing resistor through the first sampling line 31 and the second sampling line 32. Because the current through the second pad 12 and the fourth pad 22 is almost zero, the voltage detected by the detection component is almost unaffected by the impedance between the current-sensing resistor and the second pad 12 and the fourth pad 22, resulting in high accuracy of the current obtained after processing.
[0056] It should be noted that the technical solutions or features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A pad structure for a current sensing resistor, characterized by, Comprise: The first pad group and the second pad group are spaced apart along a first direction, the first pad and the second pad are spaced apart along a second direction, the third pad and the fourth pad are spaced apart along the second direction, and the second direction is perpendicular to the first direction.
2. The pad structure of claim 1, wherein The first pad and the third pad are spaced apart along the first direction, and the second pad and the fourth pad are spaced apart along the first direction.
3. The pad structure of claim 2, wherein The distance between the first pad and the third pad is equal to the distance between the second pad and the fourth pad; and / or 4. The pad structure of claim 3, wherein The distance between the first pad and the second pad is equal to the distance between the third pad and the fourth pad. The area of the first pad is equal to the area of the third pad, and the first pad and the third pad are symmetrically arranged along an axis parallel to the second direction; and / or 5. The pad structure of claim 4, wherein The area of the second pad is equal to the area of the fourth pad, and the second pad and the fourth pad are symmetrically arranged along an axis parallel to the second direction. The first detection point and the second detection point are symmetrically arranged along an axis parallel to the second direction.
6. The pad structure according to any one of claims 2 to 5, characterized in that, The first detection point is arranged on one side of the second pad close to the fourth pad, and the second detection point is arranged on one side of the fourth pad close to the second pad.
7. The pad structure of claim 6, wherein The first pad group and the second pad group are spaced apart along a first direction, the first pad and the second pad are spaced apart along the first direction, the third pad and the fourth pad are spaced apart along the first direction.
8. The pad structure of claim 1, wherein The second pad and the fourth pad are located between the first pad and the third pad.
9. The pad structure of claim 8, wherein The distance between the first pad and the second pad is equal to the distance between the third pad and the fourth pad.
10. The pad structure of claim 9, wherein The area of the first pad is equal to the area of the third pad, and the first pad and the third pad are symmetrically arranged along an axis parallel to the second direction, and the second direction is perpendicular to the first direction; and / or 11. The pad structure of claim 10, wherein The area of the second pad is equal to the area of the fourth pad, and the second pad and the fourth pad are symmetrically arranged along an axis parallel to the second direction, and the second direction is perpendicular to the first direction. The first detection point and the second detection point are symmetrically arranged along an axis parallel to the second direction, and the second direction is perpendicular to the first direction.
12. The pad structure according to any one of claims 8 to 11, characterized in that The first detection point is arranged on one side of the second pad along the second direction, and the second detection point is arranged on the same side of the fourth pad along the second direction.
13. The pad structure of claim 12, wherein The first detection point and the second detection point are both vias; and / or 14. The pad structure of claim 1, wherein The area of the first pad is greater than the area of the second pad; and / or The area of the first pad is greater than the area of the second pad; and / or The area of the third pad is greater than the area of the fourth pad.
15. A printed circuit board, characterized by The board body and the pad structure as claimed in any one of claims 1-14 are included, and the pad structure is arranged on the board body.
16. The printed circuit board of claim 15, wherein, A current detection resistor is further included and is welded with the first pad, the second pad, the third pad and the fourth pad.
17. The printed circuit board of claim 16, wherein, First and second sampling lines arranged on the board body are further included, the first sampling line is connected with the first detection point, and the second sampling line is connected with the second detection point.
18. The printed circuit board of claim 17, wherein, The first pad group and the second pad group are arranged in a first direction, and the first sampling line and the second sampling line are arranged in an axis of symmetry parallel to a second direction, and the second direction is perpendicular to the first direction.