Flexible circuit board and data center

Abstract

The present application relates to the technical field of circuit boards. Embodiments of the present application provide a flexible circuit board and a data center. The flexible circuit board (100) comprises two outer metal layers (10) arranged opposite one another and a signal line layer (20) provided between the two outer metal layers (10). The signal line layer (20) comprises at least one first signal line (21) and a first ground line (22) located on at least one side of the first signal line (21). A reference ground line (11) is provided in each of the two outer metal layers (10), and the reference ground line (11) and the first signal line (21) are stacked and arranged opposite one another. The flexible circuit board (100) further comprises a power supply line (40), and the power supply line (40) is arranged to be isolated from the first signal line (21). The flexible circuit board (100) and data center (1000) provided in the embodiments of the present application solve the problem of cables occupying excessive space.

Description

Flexible circuit boards and data centers

[0001] This application claims priority to Chinese Patent Application No. 202411448420.6, filed on October 16, 2024, entitled "Flexible Circuit Board and Data Center", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of circuit board technology, and more particularly to a flexible circuit board and a data center. Background Technology

[0003] Data centers typically require a variety of cables with different functions to meet the needs of network connectivity, data transmission, and power supply. With technological advancements, the number of cables needed in data centers is increasing, occupying significant space and leading to insufficient installation space. Summary of the Invention

[0004] The purpose of this application is to provide a flexible circuit board and a data center to solve the problem of excessive space occupied by cables.

[0005] This application provides a flexible circuit board, which includes two outer metal layers disposed opposite to each other and a signal line layer disposed between the two outer metal layers; the signal line layer includes at least one first signal line and a first ground line located on at least one side of the first signal line, and reference ground lines are respectively provided in the two outer metal layers, the reference ground lines being stacked and disposed opposite to the first signal line; the flexible circuit board also includes a power line, the power line being isolated from the first signal line.

[0006] The flexible circuit board provided in this application embodiment can transmit signals using a first signal line. A first ground line is disposed on the same layer as the first signal line and located on one side of the first signal line. The first ground line and the reference ground line can isolate and shield the first signal line. Therefore, the flexible circuit board can replace traditional cables and has good isolation and shielding effects, low signal loss, and can achieve high-speed, low-latency, and high-reliability data transmission. Simultaneously, the flexible circuit board also includes a power line, which is isolated from the first signal line, and the first signal line and the power line do not interfere with each other. Therefore, the flexible circuit board integrates both the first signal line and the power line, replacing cables with multiple functions. Compared to traditional cables, it saves a significant amount of space and reduces product weight. The aforementioned flexible circuit board solves the problem of cables occupying too much space, saving installation space.

[0007] In some embodiments, the power line includes a first sub-power line and a second sub-power line connected in parallel, wherein the first sub-power line and the second sub-power line are respectively disposed on different layers of the flexible circuit board.

[0008] In some embodiments, the first sub-power line and the second sub-power line are respectively disposed in the two outer metal layers; the power line further includes a third sub-power line formed in the signal line layer, and the first sub-power line, the second sub-power line and the third sub-power line are connected in parallel; the flexible circuit board further includes a plurality of power line vias, each power line via being connected to at least two of the first sub-power line, the second sub-power line and the third sub-power line.

[0009] In some embodiments, the number of power line through holes is greater than or equal to three; along the extension direction of the first sub-power line, at least one power line through hole is provided at one end of the first sub-power line, at least one power line through hole is provided in the middle of the first sub-power line, and at least one power line through hole is provided at the other end of the first sub-power line.

[0010] In some embodiments, the surfaces of the first sub-power line and / or the second sub-power line are provided with a thickened copper plating layer.

[0011] In some embodiments, a first ground wire is provided between the third sub-power line and the adjacent first signal line; or, no first ground wire is provided between the third sub-power line and the adjacent first signal line, and the third sub-power line and the adjacent first signal line are spaced apart by a preset distance.

[0012] In some embodiments, the first signal line adjacent to the third sub-power line is a differential signal line, which includes two differential traces arranged in parallel, and the preset distance is greater than five times the spacing between the two differential traces.

[0013] In some embodiments, there are multiple power lines, which are respectively disposed on different layers of the flexible circuit board.

[0014] In some embodiments, the first signal line is a high-speed signal line; the flexible circuit board further includes a second signal line, which is a low-speed signal line.

[0015] In some embodiments, the second signal line is disposed in the outer metal layer, and the second signal line is spaced apart from the reference ground line; along the thickness direction of the flexible circuit board, the second signal line and the first signal line are staggered and do not overlap.

[0016] In some embodiments, the second signal line is disposed in the signal line layer, and the second signal line is spaced apart from and arranged side by side with the first signal line; wherein, at least one side of the second signal line is provided with a second ground line, or the second signal line and the first signal line are isolated from each other by the first ground line.

[0017] In some embodiments, the first signal line is connected to a first connection structure at its beginning and end, the first connection structure being a solder pad or a gold finger; and / or, the power line is connected to a second connection structure at its beginning and end, the second connection structure being a solder pad or a gold finger.

[0018] This application also proposes a data center including a first device, a second device, and a flexible circuit board as described in the first aspect, the flexible circuit board being connected between the first device and the second device.

[0019] The data center provided in this application embodiment can connect the first device and the second device using a flexible circuit board. The flexible circuit board replaces a variety of cables with different functions, realizes the integration of design modules, has good substitution advantages, saves installation space, and is conducive to the miniaturization of data centers. The flexible circuit board has good shielding effect and low signal loss, and can realize high-speed, low-latency, and high-reliability data transmission.

[0020] In some embodiments, the first device and the second device are servers, respectively.

[0021] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 is a schematic diagram of the structure of the flexible circuit board provided in the first embodiment of this application;

[0024] Figure 2 is a schematic diagram of the structure of the flexible circuit board provided in the second embodiment of this application;

[0025] Figure 3 is a schematic diagram of the structure of the flexible circuit board provided in the third embodiment of this application;

[0026] Figure 4 is a schematic diagram of the structure of the flexible circuit board provided in the fourth embodiment of this application;

[0027] Figure 5 is a schematic diagram of the structure of the outer metal layer in a flexible circuit board provided in some embodiments of this application;

[0028] Figure 6 is a schematic diagram of the signal line layer in a flexible circuit board provided in some embodiments of this application;

[0029] Figure 7 is a schematic diagram of the structure of the first signal line in a flexible circuit board provided in some embodiments of this application;

[0030] Figure 8 is a schematic diagram of the structure of a data center provided in some embodiments of this application.

[0031] Explanation of key component symbols:

[0032] 1000, Data Center; 100, Flexible Circuit Board; 200, First Equipment; 300, Second Equipment;

[0033] 10. Outer metal layer; 11. Reference ground;

[0034] 20. Signal line layer; 21. First signal line; 211. Differential trace; 22. First ground line; 31. Dielectric layer; 32. Adhesive layer; 33. Cover film;

[0035] 40. Power cord; 41. First sub-power cord; 42. Second sub-power cord; 43. Third sub-power cord; 44. Copper plating layer; 45. Second connection structure;

[0036] 50, Second signal line; 60, Second ground line; 70, First connection structure; 101, Power line through hole. Embodiments of the present invention

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0038] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly or indirectly attached to that other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are for descriptive convenience only, not indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the patent. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "A plurality" means two or more, unless otherwise explicitly defined.

[0039] In this specification, references to "one embodiment," "some embodiments," or simply "embodiment" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, in one or more embodiments, specific features, structures, or characteristics may be combined in any suitable manner.

[0040] Data centers typically require a variety of cables with different functions to meet the needs of network connectivity, data transmission, and power supply. Data centers include various devices such as servers, switches, routers, and storage devices, which can be distributed within the same rack or multiple racks, requiring various types of cables to connect them. With technological advancements, the number of cables required in data centers is increasing, occupying significant space and leading to insufficient installation space. Therefore, this application provides a flexible printed circuit (FPC) that integrates multiple cable functions, thus replacing multiple cables and solving the problem of excessive cable space usage.

[0041] An embodiment of the first aspect of this application provides a flexible circuit board. Referring to FIG1, the flexible circuit board 100 includes two outer metal layers 10 disposed opposite to each other and a signal line layer 20 disposed between the two outer metal layers 10; the signal line layer 20 includes at least one first signal line 21 and a first ground line 22 located on at least one side of the first signal line 21; reference ground lines 11 are respectively provided in the two outer metal layers 10, and the reference ground lines 11 are stacked and disposed opposite to the first signal line 21; the flexible circuit board 100 also includes a power line 40, which is isolated from the first signal line 21.

[0042] Please refer to Figures 1 to 6 simultaneously. In the figures, the X direction is the length direction of the flexible circuit board 100, the Y direction is the width direction of the flexible circuit board 100, and the Z direction is the thickness direction of the flexible circuit board 100. The flexible circuit board 100 is generally elongated, and the length direction of the flexible circuit board 100 is the extension direction of the longer side of the flexible circuit board 100 with a larger size. The thickness direction of the flexible circuit board 100 is also the stacking direction of the outer metal layer 10, the signal line layer 20, and another outer metal layer 10. In some embodiments, the first signal line 21, the first ground line 22, the reference ground line 11, and the power line 40 all extend along the length direction of the flexible circuit board 100. That is, at least a portion of any one of the first signal line 21, the first ground line 22, the reference ground line 11, and the power line 40 extends along the length direction of the flexible circuit board 100. It can be understood that any one of the first signal line 21, the first ground line 22, the reference ground line 11, and the power line 40 may also simultaneously include a first segment extending along the length direction and a second segment extending along the intersection with the length direction. In addition, for ease of understanding, Figures 1 to 4 also label the first signal line 21 as S1, the power line 40 as P1, P2, the first ground line 22, the reference ground line 11, and other ground lines as G.

[0043] The flexible circuit board 100 is a multilayer board, comprising at least three stacked and spaced metal layers. The two outer metal layers 10 are a top and bottom metal layer, respectively. There are one or more inner metal layers, and at least one inner metal layer is a signal line layer 20 for mounting signal lines. Taking Figure 1 as an example, the flexible circuit board 100 includes three metal layers, labeled L1, L2, and L3 in Figure 1. L1 and L2 are the outer metal layers 10, and L2 is the signal line layer 20.

[0044] The flexible circuit board 100 also includes multiple dielectric layers 31, which insulate adjacent metal layers. The flexible circuit board 100 is formed by laminating multiple sub-boards, which can be single-sided copper-clad laminates, double-sided copper-clad laminates, or copper foil. The flexible circuit board 100 also includes an adhesive layer 32, which is laminated together with the multiple sub-boards and is used to bond adjacent sub-boards. The flexible circuit board 100 also includes multiple cover films 33, which cover the metal layers to protect the circuitry.

[0045] Signal layer 20 includes at least one first signal line 21 and a first ground line 22 located on at least one side of the first signal line 21. A first signal line 21 can be a single trace or two traces that jointly transmit signals. When the first signal line 21 is a differential signal line, it includes two differential traces. Differential transmission is a signal transmission technique that differs from the traditional approach of one signal line and one ground line. Differential transmission transmits signals on both differential traces, with the two signals having the same amplitude but opposite phase. The signals transmitted on these two differential traces are differential signals. The signal receiver compares the difference between these two voltages to determine the logic state transmitted by the transmitter. The two differential traces are of equal length, equal width, closely spaced, and on the same layer.

[0046] As shown in Figure 1, in some embodiments, the signal line layer 20 includes multiple first signal lines 21 and multiple first ground lines 22. Each first signal line 21 has two first ground lines 22 on both sides, and a first ground line 22 is provided between two adjacent first signal lines 21. The signal line layer 20 forms a ground line (G) / signal line (S) / ground line (G) structure. When the first signal line 21 is a differential signal line, no ground line is provided between the two differential traces; the first ground line 22 is only provided on one or both sides of the two differential traces.

[0047] As shown in Figure 4, in some other embodiments, a first signal line 21 near the edge of the flexible circuit board 100 is provided with a first ground line 22 on only one side, and the distance between the first signal line 21 and the adjacent line meets the preset conditions to meet the requirements of isolation and shielding.

[0048] Since the first ground line 22 and the first signal line 21 are both located on the signal line layer 20 and are set on the same layer, the first ground line 22 can play an isolation and shielding effect in the direction parallel to the board surface of the flexible circuit board 100, that is, to isolate and shield other factors (including adjacent signal lines and the external environment) from interference to the first signal line 21.

[0049] The first signal line 21 can be a high-speed signal line or a low-speed signal line. Optionally, as shown in Figure 1, the first signal line 21 is a differential signal line and includes two differential traces. It can be understood that the first signal line 21 can also be a single-ended signal line or other types of signal lines. The first signal line 21 can be a straight line, or it can include straight segments and bent segments. The first ground line 22 is set along the extension direction of the first signal line 21.

[0050] The function of the first signal line 21 is to realize signal transmission from the signal transmitting end to the signal receiving end. In order to realize the signal loop, a reference layer is needed for signal return. The two outer metal layers 10 are the reference layers of the first signal line 21, which are used to provide a signal return path for the first signal line 21. Reference ground lines 11 are respectively provided in the outer metal layers 10, that is, reference ground lines 11 are provided above and below the first signal line 21. The reference ground lines 11 are set along the extension direction of the first signal line 21, and the reference ground lines 11 are stacked and opposite to the first signal line 21. The orthogonal projection of the reference ground lines 11 on the signal line layer 20 covers at least part of the first signal line 21. The reference ground lines 11 can isolate and shield the first signal line 21 in the direction perpendicular to the board surface of the flexible circuit board 100 (Z direction in the figure), reducing the electromagnetic interference of the surrounding environment and other factors on the first signal line 21. Optionally, to improve the isolation and shielding effect, the reference ground line 11 is positioned opposite the first signal line 21. The orthographic projection of the reference ground line 11 on the signal line layer 20 covers the first signal line 21 along the width direction of the first signal line 21. The width of the reference ground line 11 can be greater than or equal to the width of the first signal line 21. The reference ground line 11 extends along the extension direction of the first signal line 21. The length of the reference ground line 11 can be equal to the length of the first signal line 21, but is not limited to this.

[0051] Optionally, multiple first signal lines 21 and reference ground lines 11 are provided, with each reference ground line 11 stacked with one first signal line 21; in other embodiments, the reference ground line 11 may also be a copper foil structure or a grid copper structure that simultaneously covers multiple first signal lines 21.

[0052] The flexible circuit board 100 also includes a power line 40, which is used to transmit power signals. The power line 40 is isolated from the first signal line 21, that is, the power line 40 and the first signal line 21 are spaced apart and can achieve signal isolation, thereby reducing interference between the power line 40 and the first signal line 21.

[0053] The power line 40 is isolated from the first signal line 21 to prevent interference between the power signal of the power line 40 and the transmission signal of the first signal line 21. The isolation method between the power line 40 and the first signal line 21 may include, but is not limited to, any of the following: the power line 40 and the first signal line 21 are respectively disposed on different metal layers of the flexible circuit board 100; a grounding shield is provided between the power line 40 and the first signal line 21; or a predetermined distance is provided between the power line 40 and the first signal line 21 (to maintain a minimum safe distance). As shown in Figure 1, in some embodiments, the power line 40 is disposed in the outer metal layer 10. P1 and P2 in Figure 1 represent two different power lines 40. The different power lines 40 can be disposed in different metal layers of the flexible circuit board 100, and the power lines 40 are spaced apart from the reference ground line 11. In other embodiments, the power line 40 can also be disposed in the inner metal layer. For example, if the power line 40 is disposed in the signal line layer 20, the power line 40 and the first signal line 21 can be isolated by setting a ground line, setting a predetermined spacing, etc., so that the power line 40 and the first signal line 21 meet the signal isolation requirements.

[0054] The flexible circuit board 100 provided in this embodiment can transmit signals using the first signal line 21. The first ground line 22 is disposed on the same layer as the first signal line 21 and is located on one side of the first signal line 21. The first ground line 22 can isolate and shield the first signal line 21. The reference ground line 11 is located on the outer metal layer 10 and is stacked and opposite to the first signal line 21. The reference ground line 11 can also isolate and shield the first signal line 21. Therefore, the flexible circuit board 100 can replace traditional cables and can provide good isolation and shielding for the first signal line 21. The signal loss is small, and high-speed, low-latency, and high-reliability data transmission can be achieved. At the same time, the flexible circuit board 100 also includes a power line 40, which is isolated from the first signal line 21. The first signal line 21 and the power line 40 do not interfere with each other. Therefore, the flexible circuit board 100 integrates the first signal line 21 and the power line 40, integrating multiple cable functions. Thus, the flexible circuit board 100 can replace multiple cables with different functions, saving a lot of space compared to traditional cables and reducing product weight. The aforementioned flexible circuit board 100 solves the problem of cables occupying too much space and saves installation space.

[0055] The flexible circuit board 100 provided in this application embodiment can be applied to data centers. The flexible circuit board 100 can connect the first and second devices of the data center, and the flexible circuit board 100 replaces signal transmission cables and power cables.

[0056] As shown in Figure 1, in the first embodiment, the flexible circuit board 100 includes two power lines 40 (P1 and P2 in Figure 1), which are respectively disposed in two outer metal layers 10, and each power line 40 can independently transmit power signals. In other embodiments, the power line 40 may also include multiple parallel sub-power lines. Referring to Figures 2 to 4, in some embodiments, the power line 40 includes a first sub-power line 41 and a second sub-power line 42 connected in parallel.

[0057] As shown in Figure 2, a second embodiment of this application provides a flexible circuit board 100, including two outer metal layers 10 disposed opposite to each other and a signal line layer 20 disposed between the two outer metal layers 10. The signal line layer 20 includes at least one first signal line 21 and a first ground line 22 located on at least one side of the first signal line 21. Reference ground lines 11 are respectively provided in the two outer metal layers 10, and the reference ground lines 11 are stacked and disposed opposite to the first signal line 21. The flexible circuit board 100 also includes a power line 40, which is isolated from the first signal line 21. In the second embodiment, the power line 40 includes a first sub-power line 41 and a second sub-power line 42 connected in parallel, and the first sub-power line 41 and the second sub-power line 42 are respectively disposed on different layers of the flexible circuit board 100.

[0058] The first sub-power line 41 and the second sub-power line 42 are respectively disposed on different layers of the flexible circuit board 100, that is, the first sub-power line 41 and the second sub-power line 42 are formed in different metal layers of the flexible circuit board 100, and the first sub-power line 41 and the second sub-power line 42 are separated by at least one dielectric layer 31.

[0059] Optionally, the first sub-power line 41 and the second sub-power line 42 are respectively disposed in two outer metal layers 10 and at least partially overlap. The first sub-power line 41 and the second sub-power line 42 are connected in parallel through power line through-holes 101, which are connected to the overlapping portion of the first sub-power line 41 and the second sub-power line 42. The number of power line through-holes 101 can be multiple. In other embodiments, at least one of the first sub-power line 41 and the second sub-power line 42 may also be disposed in the inner metal layer, and / or the first sub-power line 41 and the second sub-power line 42 may also be connected in parallel through other electrical connection structures such as conductive posts.

[0060] Optionally, both the first sub-power line 41 and the second sub-power line 42 extend along the length direction of the flexible circuit board 100; further, the first sub-power line 41 and the second sub-power line 42 are at least partially stacked along the thickness direction of the flexible circuit board 100 to facilitate the provision of the power line via 101. For example, the flexible circuit board 100 includes two power lines 40. On one side of the flexible circuit board 100 along its width direction, one power line 40 (P1 in FIG. 2) includes the first sub-power line 41 and the second sub-power line 42 connected in parallel; on the other side of the flexible circuit board 100 along its width direction, one power line 40 (P2 in FIG. 2) may also include the first sub-power line and the second sub-power line located on different layers and connected in parallel.

[0061] By adopting the above technical solution, the power line 40 includes a first sub-power line 41 and a second sub-power line 42 connected in parallel, which increases the current carrying capacity of the power line 40 and improves its current carrying capacity, enabling the power line 40 to meet the requirements of high current. Furthermore, the first sub-power line 41 and the second sub-power line 42 are respectively located in different layers of the flexible circuit board 100, saving wiring space and improving the convenience of wiring layout and maintenance. This design of the flexible circuit board 100 can adapt to situations where wiring space is insufficient.

[0062] Please continue to refer to Figure 2. In some embodiments, the first sub-power line 41 and the second sub-power line 42 are respectively disposed in the two outer metal layers 10. The power line 40 also includes a third sub-power line 43 formed in the signal line layer 20. The first sub-power line 41, the second sub-power line 42 and the third sub-power line 43 are connected in parallel. The flexible circuit board 100 is provided with a plurality of power line through holes 101. Each power line through hole 101 electrically connects at least two of the first sub-power line 41, the second sub-power line 42 and the third sub-power line 43.

[0063] Along the thickness direction of the flexible circuit board 100, the first sub-power line 41 and the second sub-power line 42 are respectively disposed on opposite sides of the third sub-power line 43; the third sub-power line 43 is disposed on the same layer as the first signal line 21 and is isolated from it. For example, as shown in FIG2, a first ground line 22 is provided between the third sub-power line 43 and the first signal line 21 adjacent to the third sub-power line 43. The first ground line 22 can isolate and shield the electromagnetic interference of the third sub-power line 43 to the first signal line 21.

[0064] In the thickness direction of the flexible circuit board 100, the first sub-power line 41 and the third sub-power line 43 at least partially overlap, and the second sub-power line 42 and the third sub-power line 43 at least partially overlap. Each power line via 101 electrically connects at least two of the first sub-power line 41, the second sub-power line 42, and the third sub-power line 43. The power line via 101 is a metallized via for electrically connecting different metal layers, wherein the power line via 101 can be a cross-layer blind via or a through-hole. Referring to Figures 2, 5, and 6, in some embodiments, the power line via 101 simultaneously connects the first sub-power line 41, the second sub-power line 42, and the third power line 43. When fabricating the power line via 101, a through-hole penetrating the two outer metal layers 10 and the signal line layer 20 can be fabricated first, and then the through-hole can be metallized to produce the power line via 101. It is understood that the power line via 101 can be fabricated together with other interlayer vias in the flexible circuit board 100.

[0065] In other embodiments, the power line through-hole 101 may also connect two of the first sub-power line 41, the second sub-power line 42, and the third sub-power line 43. For example, one power line through-hole 101 connects the first sub-power line 41 and the third sub-power line 43, and the other power line through-hole 101 connects the third sub-power line 43 and the second sub-power line 42.

[0066] In some embodiments, a plurality of power line through holes 101 are spaced apart along the length direction of the first sub-power line 41 to increase the effect of parallel connection.

[0067] By adopting the above technical solution, the power line 40 includes a first sub-power line 41, a second sub-power line 42 and a third sub-power line 43 connected in parallel through the power line through hole 101, which improves the current carrying capacity of the power line 40. The power line 40 can adapt to the needs of high current transmission. In addition, the multiple sub-power lines 40 are arranged in layers, which saves the wiring space of the flexible circuit board 100 along its width direction.

[0068] Referring to Figures 2, 5, and 6, in some embodiments, the number of power line through holes 101 is greater than or equal to three; along the extending direction of the first sub-power line 41, at least one power line through hole 101 is provided at one end of the first sub-power line 41, at least one power line through hole 101 is provided in the middle of the first sub-power line 41, and at least one power line through hole 101 is provided at the other end of the first sub-power line 41.

[0069] The first sub-power line 41, the second sub-power line 42, and the third sub-power line 43 can extend along the length direction of the flexible circuit board 100 (X direction in Figure 5). Power line through holes 101 are respectively provided at opposite ends of the power line 40 along its extension direction. The power line through holes 101 simultaneously conduct the first sub-power line 41, the second sub-power line 42, and the third sub-power line 43, so that the first sub-power line 41, the second sub-power line 42, and the third sub-power line 43 are connected in parallel. The power line through hole 101 located in the middle of the power line 40 can also conduct the first sub-power line 41, the second sub-power line 42, and the third sub-power line 43. The number of power line through holes 101 is greater than or equal to 3. The more power line through holes 101 there are, the larger the contact area between different sub-power lines, and the higher the current carrying capacity of the power line 40.

[0070] Optionally, along the extension direction of the power cord 40, multiple power cord through holes 101 are provided at both ends and in the middle of the power cord 40 to improve the current carrying capacity of the power cord 40.

[0071] In other embodiments, the power line through hole 101 may also connect two of the first sub-power line 41 and the third sub-power line 43. For example, one power line through hole 101 connects the first sub-power line 41 and the third sub-power line 43, and the other power line through hole 101 connects the third sub-power line 43 and the second sub-power line 42.

[0072] By adopting the above technical solution, the flexible circuit board 100 is provided with a plurality of power line through holes 101 for connecting the first sub-power line 41, the second sub-power line 42 and the third sub-power line 43 in parallel, which can improve the current carrying capacity and current carrying effect of the power line 40.

[0073] Referring to Figure 3, the third embodiment of this application provides a flexible circuit board 100, which differs from the second embodiment in that the surface of the first sub-power line 41 and / or the second sub-power line 42 is provided with a thickened copper plating layer 44.

[0074] Referring to Figures 3 and 5, in some embodiments, the first sub-power line 41 and the second sub-power line 42 are respectively disposed in two outer metal layers 10. The first sub-power line 41 is provided with a thickened copper plating layer 44 arranged along its extension direction, and the width of the thickened copper plating layer 44 may be less than or equal to the width of the first sub-power line 41. The second sub-power line 42 is also provided with a thickened copper plating layer 44 arranged along its extension direction, and the width of the thickened copper plating layer 44 may be less than or equal to the width of the second sub-power line 42.

[0075] During fabrication, in the circuit patterning process of the flexible circuit board 100, localized electroplating thickening can be performed on the first sub-power line 41 and / or the second sub-power line 42 through masking (dry film application, exposure, development) and electroplating operations, thereby forming a thickened copper plating layer 44 on the surface of the first sub-power line 41 and / or the second sub-power line 42. Optionally, in the step of fabricating the thickened copper plating layer 44, electroplating copper is simultaneously formed inside the power line via 101, thus completing the metallization treatment of the power line via 101. The fabrication method of the thickened copper plating layer 44 is simple and the manufacturing cost is relatively low.

[0076] In the flexible circuit board 100 provided in the third embodiment of this application, the power line 40 further includes a thickened copper plating layer 44 disposed on the first sub-power line 41 and / or the second sub-power line 42, which increases the conductor area of ​​the power line 40 and further enhances the current carrying capacity of the power line 40 to meet the requirements of high current transmission.

[0077] In other embodiments, since the third sub-power line 43 is located in the inner circuit layer, a thickened copper plating layer 44 can be provided on the surface of the third sub-power line 43 during the process of manufacturing the inner circuit.

[0078] Please refer to Figures 2 and 3. In some embodiments, a first ground line 22 is provided between the third sub-power line 43 and the first signal line 21.

[0079] Optionally, when wiring space is limited, the width of the third sub-power line 43 is less than the width of the first sub-power line 41. The orthographic projection of the third sub-power line 43 on the outer metal layer 10 falls within the range of the first sub-power line 41. It can be understood that when wiring space is sufficient, the width of the third sub-power line 43 can also be greater than or equal to the width of the first sub-power line 41.

[0080] By adopting the above technical solution, the third sub-power line 43 can be located in the same signal line layer 20 as the first signal line 21 and isolated by the first ground line 22. The first ground line 22 can shield the electromagnetic interference between the third sub-power line 43 and the first signal line 21, thus avoiding mutual interference between the third sub-power line 43 and the first signal line 21.

[0081] Referring to Figures 4 to 6, the fourth embodiment of this application provides a flexible circuit board 100. The power line 40 includes a first sub-power line 41, a second sub-power line 42, and a third sub-power line 43 connected in parallel to save wiring space. Optionally, the first sub-power line 41 and the second sub-power line 42 are provided with a thickened copper plating layer 44 to meet the requirement that the power line 40 needs to carry a large current. The difference from the third embodiment is that no first ground line 22 is provided between the third sub-power line 43 and the adjacent first signal line 21, and the third sub-power line 43 and the adjacent first signal line 21 are spaced apart by a preset distance.

[0082] In Figure 6, D indicates the preset distance between the third sub-power line 43 and the adjacent first signal line 21. This preset distance D can be set according to the isolation requirements of the first signal line 21.

[0083] By adopting the above technical solution, a first ground wire 22 on the side of the first signal line 21 closest to the third sub-power line 43 is converted into a part of the third sub-power line 43, that is, the first ground wire 22 between the third sub-power line 43 and the first signal line 21 is omitted. By setting a preset distance between the third sub-power line 43 and the first signal line 21, the required isolation and crosstalk effect of the first signal line 21 can be maintained. The width of the third sub-power line 43 can be set to be equal to the width of the first sub-power line 41 or the second sub-power line 42, which increases the conductor area and is beneficial to improving the current carrying capacity of the power line 40.

[0084] As shown in Figure 6, in some embodiments, the first signal line 21 adjacent to the third sub-power line 43 is a differential signal line. The differential signal line includes two differential traces 211 arranged in parallel, and the preset distance D is greater than five times the spacing between the two differential traces 211.

[0085] The preset distance D refers to the distance between the third power line 43 and the nearest differential trace 211.

[0086] Thus, without a first ground line 22 between the third sub-power line 43 and the adjacent differential signal line, the isolation and crosstalk effect required by the first signal line 21 can still be met by setting the distance between the third sub-power line 43 and the differential signal line.

[0087] As shown in Figures 2 to 4, the power line 40 may be provided as one or more, and at least one power line 40 includes multiple sub-power lines arranged in parallel. Referring again to Figure 1, in some embodiments, there are multiple power lines 40, and the multiple power lines 40 are respectively provided on different layers of the flexible circuit board 100.

[0088] In Figure 1, P1 and P2 respectively illustrate two power lines 40, which are respectively located in the two outer metal layers 10. It can be understood that the power lines 40 can also be located in the inner metal layer, and the pads or gold fingers connected to the power lines 40 are located in the outer metal layer 10 to realize the connection between the power lines 40 and external components.

[0089] By placing multiple power lines 40 on different layers of the flexible circuit board 100, multiple power lines 40 can be integrated onto a single flexible circuit board 100, saving the space occupied by the power lines 40.

[0090] Please refer to Figures 1 to 6 simultaneously. In some embodiments, the first signal line 21 is a high-speed signal line; the flexible circuit board 100 also includes a second signal line 50, which is a low-speed signal line.

[0091] In some embodiments, both the first signal line 21 and the second signal line 50 extend along the length of the flexible circuit board 100. The signal line labeled S1 in Figures 1 to 4 is a high-speed signal line, and the signal line labeled S2 is a low-speed signal line. The first signal line 21 is disposed in the signal line layer 20 and is a high-speed signal line capable of transmitting high-speed signals, such as a differential signal line or a single-ended signal line. The second signal line 50 is a low-speed signal line capable of transmitting low-speed signals, and the second signal line 50 can be disposed in any metal layer of the flexible circuit board 100. For example, as shown in Figures 1 to 4, the second signal line 50 is disposed in the outer metal layer 10. It can be understood that the second signal line 50 can also be disposed in the inner metal layer.

[0092] The flexible circuit board 100 provided in this application embodiment integrates high-speed signal lines, low-speed signal lines, and power lines 40, replacing multiple types of cables, saving space, and reducing product weight; the flexible circuit board 100 can achieve functional integration and modularization, enhancing its substitution advantages.

[0093] As shown in Figures 1 to 4, in some embodiments, the second signal line 50 is disposed in the outer metal layer 10, and the second signal line 50 is spaced apart from the reference ground line 11; along the thickness direction of the flexible circuit board 100, the second signal line 50 and the first signal line 21 are staggered and do not overlap.

[0094] Optionally, a second signal line 50 is provided in one or two outer metal layers 10. To avoid interference between the first signal line 21 and the second signal line 50, in this embodiment, the second signal line 50 and the first signal line 21 are staggered in the thickness direction of the flexible circuit board 100, and the second signal line 50 does not overlap with the first signal line 21. The second signal line 50 avoids the space above and below the first signal line 21. Furthermore, the reference ground line 11 of the first signal line 21 is also provided in the outer metal layer 10. The reference ground line 11 not only isolates and shields the first signal line 21 in the direction perpendicular to the flexible circuit board 100, but also isolates different second signal lines 50 in the direction parallel to the surface of the flexible circuit board 100. It can be understood that if there is sufficient wiring space in the outer metal layer 10, a second ground line 60 can also be provided on one or both sides of the second signal line 50. For example, the second ground line 60 can be provided between the second signal line 50 and the power line 40 to isolate the second signal line 50 and the power line 40.

[0095] In some embodiments of this application, the flexible circuit board 100 provides that the second signal line 50 and the first signal line 21 are disposed in different metal layers. The flexible circuit board 100 can flexibly and reasonably arrange multiple signal lines in the case of limited wiring space, which improves the convenience of signal line layout and maintenance. Since the second signal line 50 and the first signal line 21 do not overlap in the thickness direction of the flexible circuit board 100, the second signal line 50 and the first signal line 21 are not prone to mutual interference.

[0096] In some embodiments, the second signal line 50 is disposed in the signal line layer 20, and the second signal line 50 is spaced apart from and arranged side by side with the first signal line 21; wherein, at least one side of the second signal line 50 is provided with a second ground line 60, or the second signal line 50 and the first signal line 21 are isolated by a first ground line 22.

[0097] The second signal line 50 can be located in the signal line layer 20. If there is sufficient wiring space, second ground lines 60 can be set on both sides of the second signal line 50 to isolate and shield the influence of other signals on the second signal line 50. At this time, a ground line (G) / signal line (S) / ground line (G) structure is also formed at the second signal line 50. Alternatively, if the wiring space is limited, the second ground line 60 can be omitted. The second signal line 50 and the first signal line 21 adjacent to the second signal line 50 share the first ground line 22. Thus, the second signal line 50 and the first signal line 21 are isolated by the first ground line 22 to save wiring space and reduce product size.

[0098] In some embodiments of this application, the flexible circuit board 100 provides that the second signal line 50 and the first signal line 21 are disposed in the same signal line layer 20. The second ground line 60 and / or the first ground line 22 can be used to isolate the second signal line 50 and the first signal line 21, making it less likely for the second signal line 50 and the first signal line 21 to interfere with each other. The flexible circuit board 100 provided in the embodiments of this application makes full use of the ground lines of each layer to achieve isolation and shielding effects, reducing electromagnetic interference between power lines 40, signal lines, and the surrounding environment.

[0099] Please refer to Figures 1, 5 to 7. In some embodiments, the first signal line 21 is connected to a first connection structure 70 at its beginning and end, and the first connection structure 70 is a solder pad or a gold finger; and / or, the power line 40 is connected to a second connection structure 45 at its beginning and end, and the second connection structure 45 is a solder pad or a gold finger.

[0100] The beginning and end of the first signal line 21 refer to the two opposite ends of the first signal line 21 along its extension direction. Multiple first signal lines 21 are arranged side by side, and the flexible circuit board 100 can replace multiple cables adjacent to a socket or port. The first connection structure 70 is disposed on the outer metal layer 10. The first connection structure 70 is connected to the first signal line 21 through a metallized hole, and the first connection structure 70 is used to connect external components.

[0101] Figure 7 illustrates multiple first signal lines 21. For example, one first signal line 21 may be a differential signal line, and another may be a single-ended signal line, but the type of first signal line 21 is not limited to these. The first connection structure 70 is located in the outer metal layer 10. For ease of understanding, Figure 7 also illustrates the projected shape of the first connection structure 70. As shown in Figure 7, if the first connection structure 70 is a solder pad, it can be connected to external components by means of soldering or other methods. Alternatively, the first connection structure 70 may be a gold finger, which is a finger-shaped contact piece that can be connected to external components by insertion. Optionally, the gold finger may be a surface-treated contact piece, wherein the surface treatment uses a nickel-palladium-gold or hard gold treatment to enhance the wear resistance and insertion resistance of the gold finger.

[0102] Referring to Figures 1 to 5, the first and last ends of the power line 40 are respectively connected to a second connection structure 45, which is a solder pad or gold finger. When the power line 40 is located in the outer metal layer 10, the second connection structure 45 is directly connected to the power line 40; when the power line 40 is located in the inner metal layer, the second connection structure 45 can be connected to the power line 40 through conductive structures such as metallized holes. When the power line 40 includes a first sub-power line 41, a second sub-power line 42, and a third sub-power line 43 arranged in parallel, and the first sub-power line 41 is located in the outer metal layer 10, the second connection structure 45 is directly connected to the first sub-power line 41.

[0103] By adopting the above technical solution, the flexible circuit board 100 can connect the first signal line 21 and the power line 40 to external components using pads or gold fingers. The flexible circuit board 100 can not only replace cables, but also replace traditional cable connectors, reducing signal loss caused by connector soldering. The flexible circuit board 100 has a simple structure, occupies little space, and has a low manufacturing cost.

[0104] In addition, when the flexible circuit board 100 includes the second signal line 50, the first end and the last end of the second signal line 50 are respectively provided with a third connection structure. The third connection structure is provided on the outer metal layer 10 and is used to connect external components. The third connection structure can also be a solder pad or a gold finger.

[0105] Some embodiments of this application provide a flexible circuit board 100, including two outer metal layers 10 disposed opposite to each other and a signal line layer 20 disposed between the two outer metal layers 10; the signal line includes a first signal line 21 and a first ground line 22 disposed on at least one side of the first signal line 21, and reference ground lines 11 are respectively disposed in the two outer metal layers 10, the reference ground lines 11 are stacked with the first signal line 21 and disposed opposite to each other; the flexible circuit board 100 also includes a power line 40 and a second signal line 50, different power lines 40 are disposed in different layers, or the power line 40 includes multiple sub-power lines 40 connected in parallel; the first signal line 21 is a high-speed signal line, the second signal line 50 is a low-speed signal line, and the second signal line 50 is disposed in the outer metal layer 10 or the signal line layer 20.

[0106] Please refer to Figures 1 to 8. An embodiment of the second aspect of this application proposes a data center 1000, including a first device 200, a second device 300, and a flexible circuit board 100 as provided in the first aspect, wherein the flexible circuit board 100 is connected between the first device 200 and the second device 300.

[0107] Data center 1000 is a facility used for storing, managing, and transmitting large amounts of data. The first device 200 and the second device 300 may be servers, switches, routers, etc., but are not limited to these. For example, the first device 200 and the second device 300 may be different servers within data center 1000, with flexible circuit board 100 connecting the two servers.

[0108] The data center 1000 provided in this application embodiment can connect the first device 200 and the second device 300 using the flexible circuit board 100. The flexible circuit board 100 replaces a variety of cables with different functions, realizes the integration of design modules, saves installation space, and is conducive to the miniaturization of the data center 1000. The flexible circuit board 100 has good shielding effect and low signal loss, and can realize high-speed, low-latency, and high-reliability data transmission.

[0109] This application provides a wiring method for a flexible circuit board 100, including: first determining the position of a first signal line 21 in a signal line layer 20, and determining the position of a first ground line 22 in a signal line layer 20 and the position of a reference ground line 11 in two outer metal layers 10 based on the position of the first signal line 21; then determining the position of a power line 40 in the flexible circuit board 100, wherein multiple power lines 40 are respectively disposed in different layers, or at least one power line 40 is configured as multiple parallel sub-power lines 40.

[0110] The first ground line 22 is disposed on one or both sides of the first signal line 21, and the reference ground line 11 is stacked and disposed opposite to the first signal line 21, so that the orthogonal projection of the reference ground line 11 in the signal line layer 20 covers at least part of the first signal line 21.

[0111] The power line 40 is isolated from the first signal line 21. Specifically, when there is sufficient wiring space, multiple power lines 40 can be disposed on different metal layers. The power lines 40 can be disposed in the outer metal layer 10 or the inner metal layer; or, at least one power line 40 can be configured as multiple parallel sub-power lines 40. For example, the power lines 40 can be configured as a first sub-power line 41, a second sub-power line 42, and a third sub-power line 43 connected in parallel. The first sub-power line 41 and the second sub-power line 42 are respectively disposed in the two outer metal layers 10, and the third sub-power line 43 is disposed in the signal line layer 20. The first sub-power line 41, the second sub-power line 42, and the third sub-power line 43 are connected in parallel through power line through holes 101. The number of power line through holes 101 can be multiple and they are spaced apart along the extension direction of the first sub-power line 41.

[0112] The first signal line 21 can be a high-speed signal line. This wiring method prioritizes the layered design of high-speed cables with high isolation and crosstalk requirements, so that the first signal line 21 runs in the inner layer, and the two outer metal layers 10 are used as the reference layers for the first signal line 21. Then, the power line 40 is layered.

[0113] The wiring method of the flexible circuit board 100 described above can flexibly arrange the first signal line 21 and the power line 40, so that the flexible circuit board 100 can replace cables with multiple functions. It can not only achieve the isolation and shielding effect of the first signal line 21, but also make reasonable use of the wiring space in the flexible circuit board 100, which is conducive to reducing the size of the flexible circuit board 100.

[0114] In some embodiments, the first signal line 21 is a high-speed signal line, and the wiring method further includes: determining the position of the second signal line 50 in the flexible circuit board 100, wherein the second signal line 50 is a low-speed signal line, wherein the second signal line 50 is disposed in the signal line layer 20, or the second signal line 50 is disposed in the outer metal layer 10 and the second signal line 50 and the first signal line 21 are offset from each other in the thickness direction of the flexible circuit board 100.

[0115] When there is sufficient wiring space, at least one side of the second signal line 50 is provided with a second ground line 60, that is, the second signal line 50 adopts a structure design of ground line (G) / signal line (S) / ground line (G); when there is insufficient wiring space, the second signal line 50 can share the first ground line 22 with the first signal line 21, or the second signal line 50 can be placed in the outer metal layer 10 and the second signal line 50 can be staggered from the first signal line 21. Along the thickness direction of the flexible circuit board 100, the second signal line 50 avoids the space directly opposite the first signal line 21.

[0116] The wiring method of the flexible circuit board 100 described above can also arrange a second signal line 50 in the flexible circuit board 100, respectively using the first signal line 21 to realize high-speed signal transmission and using the second signal line 50 to realize low-speed signal transmission. The wiring method is more flexible and can adapt to different wiring spaces.

[0117] When designing the flexible circuit board 100, the position of the power line 40 can be determined first, followed by the position of the second signal line 50, or vice versa. Furthermore, the routing method for the flexible circuit board 100 also includes simulating the designed data to correct the relationships between signal loss, line spacing, material thickness, and dielectric constant (DK). Then, the product can be manufactured according to the design data, and its functionality can be tested.

[0118] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A flexible circuit board, wherein, The flexible circuit board includes two opposing outer metal layers and a signal line layer disposed between the two outer metal layers; The signal line layer includes at least one first signal line and a first ground line located on at least one side of the first signal line. Reference ground lines are respectively provided in the two outer metal layers. The reference ground lines are stacked with the first signal line and are disposed opposite to it. The flexible circuit board also includes a power line, which is isolated from the first signal line.

2. The flexible circuit board as described in claim 1, wherein, The power line includes a first sub-power line and a second sub-power line connected in parallel, and the first sub-power line and the second sub-power line are respectively disposed on different layers of the flexible circuit board.

3. The flexible circuit board as described in claim 2, wherein, The first sub-power line and the second sub-power line are respectively disposed in the two outer metal layers; the power line also includes a third sub-power line formed in the signal line layer, and the first sub-power line, the second sub-power line and the third sub-power line are connected in parallel. The flexible circuit board also includes a plurality of power line vias, each of which is electrically connected to at least two of the first sub-power line, the second sub-power line, and the third sub-power line.

4. The flexible circuit board as described in claim 3, wherein, The number of power line through holes is greater than or equal to three; Along the extension direction of the first sub-power line, at least one power line through hole is provided at one end of the first sub-power line, at least one power line through hole is provided in the middle of the first sub-power line, and at least one power line through hole is provided at the other end of the first sub-power line.

5. The flexible circuit board as described in claim 3, wherein, The surface of the first sub-power line and / or the second sub-power line is provided with a thickened copper plating layer.

6. The flexible circuit board as described in claim 3, wherein, A first ground wire is provided between the third sub-power line and the adjacent first signal line; or, The third sub-power line and the adjacent first signal line are not connected by a first ground line, and the third sub-power line and the adjacent first signal line are spaced apart by a preset distance.

7. The flexible circuit board as described in claim 6, wherein, The first signal line adjacent to the third sub-power line is a differential signal line, which includes two differential traces arranged in parallel, and the preset distance is greater than five times the spacing between the two differential traces.

8. The flexible circuit board as claimed in claim 1, wherein, There are multiple power lines, which are respectively located on different layers of the flexible circuit board.

9. The flexible circuit board as described in any one of claims 1-8, wherein, The first signal line is a high-speed signal line; the flexible circuit board also includes a second signal line, which is a low-speed signal line.

10. The flexible circuit board as claimed in claim 9, wherein, The second signal line is disposed in the outer metal layer, and the second signal line is spaced apart from the reference ground line; along the thickness direction of the flexible circuit board, the second signal line and the first signal line are staggered and do not overlap.

11. The flexible circuit board as claimed in claim 9, wherein, The second signal line is disposed in the signal line layer, and the second signal line is spaced apart from and arranged side by side with the first signal line; Wherein, at least one side of the second signal line is provided with a second ground line, or, The second signal line is isolated from the first signal line through the first ground line.

12. The flexible circuit board according to any one of claims 1-8, wherein, The first signal line has a first connection structure connected to its beginning and end, wherein the first connection structure is a solder pad or a gold finger; and / or, The first and last ends of the power cord are respectively connected to a second connection structure, which is a solder pad or a gold finger.

13. A data center, comprising a first device and a second device, wherein, The data center further includes a flexible circuit board as described in any one of claims 1-12, the flexible circuit board being connected between the first device and the second device.

14. The flexible circuit board as described in claim 13, wherein the first device and the second device are servers, respectively.

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