Battery protection board
By optimizing the wiring method of the current sampling line in the laptop battery protection board, it is pulled out from the middle position of the precision resistor, the current sampling inaccurate problem caused by incomplete packet AGND network is solved, and higher sampling accuracy is achieved.
Patent Information
- Application Number
- CN202421549683.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-02
- Publication Date
- 2025-06-06
- Estimated Expiration
- 2034-07-02
AI Technical Summary
In the design of laptop battery protection board, due to space limitations, the current sampling line of the precision resistor is easily incomplete when the AGND network copper foil is wrapped, resulting in excessive leakage current and inaccurate current sampling of the precision resistor.
By optimizing the wiring method of the current sampling line on the substrate, the current sampling line is drawn out from the intermediate position of the precision resistor and connected to the differential signal input end of the charge meter to avoid errors caused by the difference in potentials at both ends of the precision resistor.
It achieves improving the current sampling accuracy of precision resistors and solves the problem of inaccurate current sampling.
Smart Images
Figure CN222953289U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of laptop battery protection boards, and in particular to a battery protection board. Background Art
[0002] At present, in the design of laptop battery protection boards, most projects use precision resistors to detect the current size. Laptop battery protection boards are getting smaller and smaller. Due to space limitations, when the current sampling line of the precision resistor is wrapped with AGND (Anal og Ground) network copper foil, there will be an incomplete AGND network, resulting in excessive leakage current, resulting in inaccurate current sampling of the precision resistor. Utility Model Content
[0003] The present application provides a battery protection board to solve the technical problem of inaccurate current sampling of precision resistors.
[0004] In a first aspect, the present application provides a battery protection board, comprising: a substrate, the substrate being provided with a precision resistor, a fuel meter and a current sampling line, the precision resistor being connected to the fuel meter through the current sampling line, wherein the current sampling line is led out from the middle position of the precision resistor and connected to the differential signal input terminal of the fuel meter.
[0005] As an optional example, the current sampling line includes a first current sampling line and a second current sampling line, the first end of the first current sampling line is connected to the positive electrode of the precision resistor, the second end of the first current sampling line is connected to the differential signal input end of the fuel meter, the first end of the second current sampling line is connected to the negative electrode of the precision resistor, and the second end of the second current sampling line is connected to the differential signal input end of the fuel meter.
[0006] As an optional example, the differential signal input terminal of the above-mentioned fuel meter includes a first differential signal input terminal and a second differential signal input terminal, the first differential signal input terminal of the above-mentioned fuel meter is connected to the second end of the above-mentioned first current sampling line, and the second differential signal input terminal of the above-mentioned fuel meter is connected to the second end of the above-mentioned second current sampling line.
[0007] As an optional example, the first current sampling line and the second current sampling line have the same length and width and are parallel.
[0008] As an optional example, the first current sampling line and the second current sampling line are surrounded by a complete AGND network.
[0009] As an optional example, the battery protection board further includes at least one first AGND hole, which is arranged on an AGND network surrounding the current sampling line, and is used to connect the AGND network surrounding the current sampling line and the AGND network of an adjacent layer.
[0010] As an optional example, the battery protection board further includes a capacitor, and the capacitor is connected to the differential signal input terminal of the fuel meter.
[0011] As an optional example, the above capacitor is surrounded by a complete AGND network.
[0012] As an optional example, the battery protection board further includes at least one second AGND hole, which is arranged on the AGND network surrounding the capacitor, and is used to connect the AGND network surrounding the capacitor and the AGND network of an adjacent layer.
[0013] As an optional example, the AGND network is copper foil.
[0014] In an embodiment of the present application, a substrate is used, and the substrate is provided with a precision resistor, a fuel meter and a current sampling line. The precision resistor is connected to the fuel meter through the current sampling line, wherein the current sampling line is led out from the middle position of the precision resistor and connected to the battery protection board at the differential signal input end of the fuel meter. Since the routing method of the current sampling line on the substrate is optimized in the battery protection board, the current sampling line is led out from the middle position of the precision resistor, which can avoid the error caused by the potential difference at both ends of the precision resistor, thereby achieving the purpose of improving the current sampling accuracy of the precision resistor, and then solving the technical problem of inaccurate current sampling of the precision resistor. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0017] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.
[0018] Figure 1 is a schematic structural diagram of an optional battery protection board according to an embodiment of the present application;
[0019] Figure 2 This is a schematic diagram of a circuit board of an optional battery protection board according to an embodiment of the present application. DETAILED DESCRIPTION
[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0021] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.
[0022] The present application provides a battery protection board, optionally, as Figure 1 As shown, the battery protection board includes:
[0023] The substrate 102 is provided with a precision resistor 104 , a power meter 106 and a current sampling line 108 . The precision resistor 104 and the power meter 106 are connected via the current sampling line 108 , wherein the current sampling line 108 is led out from the middle position of the precision resistor 104 and connected to the differential signal input terminal of the power meter 106 .
[0024] Optionally, in the design of laptop battery protection boards, most projects currently use precision resistors to detect the magnitude of current. Laptop battery protection boards are getting smaller and smaller. Due to space limitations, when the current sampling line of the precision resistor is wrapped with AGND network copper foil, there will be an incomplete AGND network, resulting in excessive leakage current, which leads to inaccurate current sampling of the precision resistor. Therefore, in this embodiment, a precision resistor 104, a power meter 106, and a current sampling line 108 are provided on the substrate 102, and the routing method of the current sampling line 108 on the substrate 102 is optimized. The middle position, that is, the middle position of the precision resistor 104, the current sampling line 108 is led out from the middle position of the precision resistor 104, and the voltage drop on half of the precision resistor 104 is measured, which can avoid the error caused by the potential difference between the two ends of the precision resistor 104, thereby achieving the purpose of improving the accuracy of the current sampling of the precision resistor, and then solving the technical problem of inaccurate current sampling of the precision resistor.
[0025] Optionally, the current sampling line 108 plays a vital role in the fuel gauge 106 (such as a battery management IC), and is responsible for extracting a voltage signal from the precision resistor 104 and transmitting it to the differential signal input pins (SRP and SRN) of the fuel gauge 106, so as to measure the current passing through the precision resistor 104. In this embodiment, the precision resistor 104 is connected to the fuel gauge 106 through the current sampling line 108, and the current sampling line 108 is extracted from the middle position of the precision resistor 104 and connected to the differential signal input terminals SRP and SRN of the fuel gauge 106, respectively, to reduce the influence of the lead resistance and the PCB trace resistance on the measurement.
[0026] As an optional example, the current sampling line includes a first current sampling line and a second current sampling line, the first end of the first current sampling line is connected to the positive electrode of the precision resistor, the second end of the first current sampling line is connected to the differential signal input end of the fuel meter, the first end of the second current sampling line is connected to the negative electrode of the precision resistor, and the second end of the second current sampling line is connected to the differential signal input end of the fuel meter.
[0027] Optionally, in this embodiment, the current sampling line includes a first current sampling line and a second current sampling line, wherein the first end of the first current sampling line is connected to the positive electrode of the precision resistor, and the second end of the first current sampling line is connected to the differential signal input terminal SRP (Sense Res is stor Pos it i ve) of the fuel meter to measure the positive electrode voltage of the voltage difference across the precision resistor. The first end of the second current sampling line is connected to the negative electrode of the precision resistor, and the second end of the second current sampling line is connected to the differential signal input terminal SRN of the fuel meter to measure the negative electrode voltage of the voltage difference across the precision resistor.
[0028] As an optional example, the differential signal input terminal of the fuel meter includes a first differential signal input terminal and a second differential signal input terminal, the first differential signal input terminal of the fuel meter is connected to the second end of the first current sampling line, and the second differential signal input terminal of the fuel meter is connected to the second end of the second current sampling line.
[0029] Optionally, in this embodiment, the functions of the SRP (Sense Res is stor Pos it ive) and SRN (Sense Res is stor Negative) pins in the fuel meter are differential inputs for current sampling, and are respectively connected to the two ends of the precision resistor to measure the current passing through the precision resistor. The SRP pin is connected to the positive terminal of the precision resistor through the first current sampling line, and measures the positive voltage of the voltage difference between the two ends of the precision resistor. As part of the differential signal input, it works with the SRN pin to measure the current passing through the precision resistor. The SRN pin is connected to the negative terminal of the precision resistor through the second current sampling line, and measures the negative voltage of the voltage difference between the two ends of the precision resistor. Together with the SRP pin, it constitutes a differential input pair, and the current is calculated by measuring the voltage difference. The fuel meter measures the voltage difference between the two ends of the precision resistor through the SRP and SRN pins. Since the SRP pin is connected to the positive terminal of the precision resistor and the SRN pin is connected to the negative terminal of the precision resistor, the fuel meter can accurately measure the voltage difference caused by the current.
[0030] As an optional example, the first current sampling line and the second current sampling line have the same length and width and are parallel.
[0031] Optionally, in this embodiment, if Figure 2 In the schematic diagram of the circuit board shown, 1 is the first current sampling line, 2 is the second current sampling line, 3 is the AGND hole, 4 is the AGND network, 5 is the precision resistor, and 6 is the power meter. The first current sampling line 1 and the second current sampling line 2 adopt a differential routing design. The two differential lines need to be equidistant, equal in length, equal in width, and parallel to maintain the symmetry of the routing, and try to avoid sharp turns and irregular routing. Avoid phase differences and errors introduced by inconsistent line lengths, and effectively reduce the impact of external electromagnetic interference on the signal. The two current sampling lines transmit signals in a differential manner, that is, the voltage difference between the two ends of the resistor is transmitted, which can improve the anti-interference ability and measurement accuracy.
[0032] As an optional example, the first current sampling line and the second current sampling line are surrounded by a complete AGND network.
[0033] Optionally, in this embodiment, if Figure 2In the schematic diagram of the circuit board shown in the figure, the area around the first current sampling line and the second current sampling line is filled with AGND (analog ground) to form a continuous AGND area, so that the first current sampling line 1 and the second current sampling line 2 are surrounded by the complete AGND network 4, and vias and signal lines of other networks are not allowed to appear around the current sampling lines. This reduces external electromagnetic interference and improves signal integrity and accuracy. In the multi-layer PCB design, there is at least one substrate, and precision resistors, a power meter, and current sampling lines are set on one of the substrates. One of the independent substrates is allocated to the AGND network to ensure the integrity of the AGND network and avoid placing signal lines on the AGND plane to avoid introducing noise.
[0034] As an optional example, the battery protection board further includes at least one first AGND hole, which is arranged on an AGND network surrounding the current sampling line, and is used to connect the AGND network surrounding the current sampling line and the AGND network of an adjacent layer.
[0035] Optionally, in this embodiment, if Figure 2 As shown in the circuit board schematic diagram, in a multi-layer PCB design, AGND vias are used to connect the AGND planes of different layers together to form a continuous AGND network. The first AGND hole is drilled on the AGND network surrounding the current sampling line. If there is enough space, double vias can be used to connect to the AGND network of adjacent layers or other layers to enhance shielding interference.
[0036] As an optional example, the battery protection board further includes a capacitor, and the capacitor is connected to the differential signal input terminal of the fuel meter.
[0037] Optionally, in this embodiment, a filter capacitor may be placed near the SRP pin and the SRN pin of the fuel meter, with one end of the capacitor connected to the current sampling line and the other end connected to AGND.
[0038] As an alternative example, the capacitor is surrounded by a complete AGND network.
[0039] Optionally, in this embodiment, if Figure 2 As shown in the schematic diagram of the circuit board, the line and resistor and capacitor components at one end close to the fuel meter 6 need to be surrounded by a complete AGND network 4, so as to reduce external electromagnetic interference and improve signal integrity and accuracy.
[0040] As an optional example, the battery protection board further includes at least one second AGND hole, the second AGND hole is arranged on the AGND network surrounding the capacitor, and the second AGND hole is used to connect the AGND network surrounding the capacitor and the AGND network of an adjacent layer.
[0041] Optionally, in this embodiment, if Figure 2 In the circuit board schematic diagram shown, AGND vias are drilled around the AGND network of the capacitor connected to the SRP pin and SRN pin of the fuel gauge 6 to connect the AGND network of the adjacent layer or other layers to enhance shielding interference.
[0042] Optionally, the width of the substrate is widened on the original basis, so that the devices around the power meter are away from the AGND copper foil, and the AGND copper foil is completely wrapped and the AGND network vias are drilled to connect with the adjacent layer or other layer AGND network.
[0043] Optionally, when designing the current sampling line, the present application drills AGND holes on the AGND network around the current sampling line, especially drills AGND holes around the capacitors connected to the SRP pin and SRN pin of the power meter to connect them to the AGND network of adjacent layers or other layers to enhance shielding interference. Without increasing the cost, the sampling accuracy of the precision resistor is improved only by optimizing the routing and drilling methods of the current sampling line on the substrate.
[0044] As an optional example, the AGND network is copper foil.
[0045] Optionally, in this embodiment, if Figure 2 In the schematic diagram of the circuit board shown in the figure, the AGND network 5 filled around the first current sampling line 1 and the second current sampling line 2 and around the capacitor is made of copper foil material, and may also be other alternative metal materials.
[0046] It should be noted that, for the above-mentioned battery protection board embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the described order of actions, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.
Claims
1. A battery protection board, characterized in that: include: A substrate is provided with a precision resistor, a fuel gauge and a current sampling line, wherein the precision resistor is connected to the fuel gauge through the current sampling line, wherein the current sampling line is led out from the middle position of the precision resistor and connected to the differential signal input terminal of the fuel gauge.
2. The battery protection board according to claim 1, characterized in that: The current sampling line includes a first current sampling line and a second current sampling line, wherein the first end of the first current sampling line is connected to the positive electrode of the precision resistor, the second end of the first current sampling line is connected to the differential signal input end of the fuel gauge, the first end of the second current sampling line is connected to the negative electrode of the precision resistor, and the second end of the second current sampling line is connected to the differential signal input end of the fuel gauge.
3. The battery protection board according to claim 2, characterized in that: The differential signal input end of the fuel meter includes a first differential signal input end and a second differential signal input end. The first differential signal input end of the fuel meter is connected to the second end of the first current sampling line, and the second differential signal input end of the fuel meter is connected to the second end of the second current sampling line.
4. The battery protection board according to claim 2, characterized in that: The first current sampling line and the second current sampling line have the same length and width and are parallel.
5. The battery protection board according to claim 2, characterized in that: The first current sampling line and the second current sampling line are surrounded by a complete AGND network.
6. The battery protection board according to claim 5, characterized in that: The battery protection board further includes at least one first AGND hole, which is disposed on an AGND network surrounding the current sampling line, and is used to connect the AGND network surrounding the current sampling line and an AGND network of an adjacent layer.
7. The battery protection board according to claim 1, characterized in that: The battery protection board also includes a capacitor, which is connected to the differential signal input terminal of the fuel gauge.
8. The battery protection board according to claim 7, characterized in that: The capacitor is surrounded by a complete AGND network.
9. The battery protection board according to claim 8, characterized in that: The battery protection board further includes at least one second AGND hole, wherein the second AGND hole is arranged on an AGND network surrounding the capacitor, and the second AGND hole is used to connect the AGND network surrounding the capacitor and an AGND network of an adjacent layer.
10. The battery protection board according to claim 9, characterized in that: The AGND network is copper foil.