Printed circuit board, printed circuit board design method, and server

Abstract

The application provides a printed circuit board, a printed circuit board design method and a server, comprising a plurality of signal layers, signal wires arranged in each signal layer and ground signal wires corresponding to the signal wires; wherein the signal wires are signal transmission paths of the signal layers, and the ground signal wires are signal return paths of the signal layers, the printed circuit board provided by the application achieves the purpose of removing the ground layer and also transmitting signals, reduces the number of board layers and design cost of the printed circuit board, and also reduces the size of the printed circuit board, and optimizes the miniaturized design of the printed circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of servers, in particular to a printed circuit board, a printed circuit board design method and a server. BACKGROUND

[0002] With the design of electronic products becoming more and more miniaturized and the functions becoming more and more complex and powerful, the circuit system design is more and more complex and large. Further, in the case of the reduction of the area of the PCB (Printed Circuit Board) card, the number of devices on the PCB card increases, the pin density of the PCB card increases extremely, the design difficulty of the PCB card increases, the overall electrical performance of the system decreases, and the overall PCB card product design cost increases.

[0003] When the pin density of the PCB card increases to a certain extent, the area of the PCB card cannot continue to be reduced, which hinders the design of electronic products to be more and more miniaturized, and to some extent, limits the functions of electronic products.

[0004] In the design of a cloud storage server, with the increase of the signal rate, the signal changes with the running environment, and the requirement for signal transmission quality is higher and higher. SUMMARY

[0005] The present application provides a printed circuit board, a printed circuit board design method and a server, which are used for optimizing the design of a printed circuit board.

[0006] The present application provides a printed circuit board, comprising: a plurality of signal layers, signal wires arranged in each of the signal layers, and ground signal wires corresponding to the signal wires.

[0007] The signal wire is a signal transmission path of the signal layer, and the ground signal wire is a signal return path of the signal layer.

[0008] According to the printed circuit board provided by the present application, the signal layer includes a first signal layer for transmitting a single-ended signal.

[0009] The unit wire in the first signal layer includes one first signal wire and one first ground signal wire.

[0010] According to the printed circuit board provided by the present application, the signal layer includes a second signal layer for transmitting a differential signal.

[0011] The unit wire in the second signal layer includes two second signal wires and two second ground signal wires; or

[0012] The unit wire in the second signal layer includes two second signal wires and three second ground signal wires.

[0013] According to the printed circuit board provided in the application, the copper thickness of the signal trace of the signal layer is N microns, wherein the N is a natural number greater than 1.

[0014] The N is related to the impedance of the signal trace.

[0015] According to the printed circuit board provided in the application, the line width of the signal trace of the signal layer is less than the line width of a reference signal trace, wherein the reference signal trace is a signal trace of a ground layer adjacent to the signal layer and serving as a signal return path.

[0016] The line width of the signal trace is related to the N.

[0017] The application further provides a printed circuit board design method applied to the printed circuit board.

[0018] Removing the ground layer matched with each signal layer in the printed circuit board;

[0019] Sequentially setting a corresponding ground signal trace for each signal trace in each signal layer;

[0020] The signal trace is a signal transmission path of the signal layer, and the ground signal trace is a signal return path of the signal layer.

[0021] According to the printed circuit board design method provided in the application, the step of sequentially setting a corresponding ground signal trace for each signal trace in each signal layer comprises:

[0022] Sequentially increasing the copper thickness of each signal trace in each signal layer from M microns to N microns, wherein the N is related to the impedance of the signal trace.

[0023] According to the printed circuit board design method provided in the application, after the step of sequentially increasing the copper thickness of each signal trace in each signal layer from M microns to N microns, the method further comprises:

[0024] Sequentially reducing the line width of each signal trace in each signal layer, wherein the line width of the signal trace is related to the N.

[0025] The application further provides a server comprising the printed circuit board.

[0026] The application provides a printed circuit board, a printed circuit board design method and a server, which comprise a plurality of signal layers, signal lines arranged in each signal layer and ground signal lines corresponding to the signal lines; wherein the signal lines are signal transmission paths of the signal layers, and the ground signal lines are signal return paths of the signal layers; thus, the printed circuit board provided by the application has corresponding ground signal lines designed for the signal lines in each signal layer, so that signals are transmitted from the signal lines and returned from the ground signal lines, and thus the printed circuit board provided by the application does not need to design an adjacent ground layer for each signal layer as a return path of the signals transmitted by the signal layers; since the ground layer is removed, the number of board layers of the printed circuit board can be reduced, the cost of the printed circuit board is reduced, meanwhile, the volume of the printed circuit board is reduced, and the miniaturization design of the printed circuit board is optimized. BRIEF DESCRIPTION OF DRAWINGS

[0027] The drawings incorporated in the specification and constituting a part thereof illustrate embodiments consistent with the application and together with the specification are used to explain the principles of the application.

[0028] In order to more clearly illustrate the technical solutions of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0029] Figure 1 is a schematic diagram of the laminated structure of the printed circuit board in the prior art solution provided by the application;

[0030] Figure 2 is a schematic diagram of the laminated structure of the printed circuit board provided by the application;

[0031] Figure 3 is one of the schematic diagrams of the wiring structure of the signal layer of the printed circuit board provided by the application;

[0032] Figure 4 is another schematic diagram of the wiring structure of the signal layer of the printed circuit board provided by the application;

[0033] Figure 5 is a third schematic diagram of the wiring structure of the signal layer of the printed circuit board provided by the application;

[0034] Figure 6 is a fourth schematic diagram of the wiring structure of the signal layer of the printed circuit board provided by the application;

[0035] Reference signs:

[0036] 101: top layer; 102: ground layer; 103: power layer; 104: signal layer; 105: bottom layer; 106: device; 1041: signal trace; 1042: ground signal trace. DETAILED DESCRIPTION

[0037] In order to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0038] In the description of the embodiments of the present application, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0040] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0041] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0042] It should be noted that the reference Figure 1 , the design principle of the stack of the printed circuit board in the prior art is that each signal layer (i.e. the wiring layer) must have an adjacent reference layer (power layer or ground layer), so that the reference layer (power layer or ground layer) and each adjacent signal layer (i.e. the wiring layer) form a signal loop, so that the current signal can flow from device A at one end of the signal layer to device B at the other end, and then return to device A through the adjacent reference layer (power layer or ground layer).

[0043] Figure 1 For the stack design scheme of the 12-layer board in the prior art, such as Figure 1 The stack of the 12-layer board in the prior art is usually composed of a top layer 101, four ground layers 102, two power layers 103, four signal layers 104 and a bottom layer 105.

[0044] Among them, the signal layer 104 is the same copper conductive layer as the top layer 101 and the bottom layer 105, but the wiring layer sandwiched between the top layer 101 and the bottom layer 105, the top layer 101, the bottom layer 105 and the signal layer 104 are used to arrange the conductors on the printed circuit board, to carry the current signals between the devices in the printed circuit board through the conductors, the power layer 103 and the ground layer 102 are used as the reference plane layer of the signal layer, to carry out controlled impedance wiring for the signal layer, to provide interference current signal shielding and consistent characteristic impedance.

[0045] Because the current always flows in a loop, if some current flows elsewhere, it must return to the source. In order to realize the transmission of signals, such as Figure 1As shown, one adjacent ground layer 102 is arranged between two signal layers 104 in the stack of the printed circuit board, wherein the signal traces in the signal layers 104 serve as signal transmission paths, and the signal return paths are directly below the adjacent ground layers 102 of the signal layers 104, and the higher the sine wave frequency of the current signal is, the closer the current signal is distributed, and thus one ground layer 102 is required for one signal layer 104, and two layers can constitute a complete signal path.

[0046] However, as the design of the sub-products tends to be smaller and more complex, the circuit system design becomes more complex and large. The number of devices arranged on the printed circuit board increases, and the number of signal lines required to be arranged on the printed circuit board also increases, and the pin density of the printed circuit board increases extremely, thereby increasing the design difficulty of the printed circuit board, reducing the overall electrical performance of the system, and increasing the overall design cost of the printed circuit board product.

[0047] To solve the above technical problems, the embodiments of the present application provide a printed circuit board. The printed circuit board provided by the embodiments of the present application does not need to design an adjacent ground layer for each signal layer as a return path of the signal transmitted by the signal layer. Since the ground layer is removed, the number of board layers of the printed circuit board can be reduced, the cost of the printed circuit board is reduced, the volume of the printed circuit board is reduced, and the miniaturization design of the printed circuit board is optimized.

[0048] The printed circuit board provided by the embodiments of the present application will be described below. Figures 2 to 6 The printed circuit board provided by the embodiments of the present application will be described below.

[0049] As shown in Figure 2 and Figure 3 As shown in Figure 2 A 12-layer stack design scheme provided by the embodiments of the present application is provided, and the 12-layer stack provided by the embodiments of the present application is composed of a top layer 101, ten signal layers 104, and a bottom layer 105, Figure 3 A trace structure diagram of each signal layer 104 provided by the embodiments of the present application is provided.

[0050] The printed circuit board provided by the embodiments of the present application includes a plurality of signal layers 104, signal traces 1041 arranged in each of the signal layers 104, and ground signal traces 1042 corresponding to the signal traces, wherein the signal traces 1041 are signal transmission paths of the signal layers 104, and the ground signal traces 1042 are signal return paths of the signal layers 104.

[0051] Specifically, the signal trace 1041, also referred to as a copper mode wire, is used to transmit a current signal and realize physical connection of a circuit of the device 106 at both ends of the signal layer 104. The signal trace 1041 runs from one soldering point to another soldering point, and the width and trace path of the signal trace 1041 directly affect the performance of the entire printed circuit board.

[0052] In the embodiment, all the ground layers 102 and the power layers 103 in the stack of the printed circuit board are removed, and only the top layer 101 and the plurality of signal layers 104 are reserved. In the original printed circuit board, the ground layer 102 is used as a signal return path when a current signal is transmitted. In the embodiment, after removing all the ground layers 102 in the stack of the printed circuit board, the signal cannot be transmitted or the signal transmission quality is very poor. To solve the technical problem, the corresponding ground signal trace 1042 is arranged beside the signal trace 1041 in each signal layer 104, the ground signal trace 1042 is used as a signal return path, each signal has its own independent return path, and the ground signal trace 1042 follows the signal trace 1041 throughout, which can avoid crosstalk and is beneficial to signal quality.

[0053] In the embodiment, the ground signal trace 1042 is made of the same material as the signal trace 1041 and is in the same layer, but the transmission direction of the signal is different.

[0054] In addition, it should be noted that the design principle of the ground signal trace 1042 in the embodiment is that the signal path provided by the ground signal trace 1042 is the path with the lowest impedance that can be found in the frequency of the signal transmitted by the signal trace 1041, that is, the line trace of the ground signal trace 1042 of the signal trace 1041 in the signal layer 104 is determined according to the frequency of the signal transmitted by the signal trace 1041 in the signal layer 104. In this way, the energy of the signal will be contained and will not overflow the plane to the next layer in the stack of the printed circuit board, which helps to prevent the energy of the signal from interfering with other signals in the area.

[0055] In some embodiments, the signal layer 104 includes a first signal layer for transmitting a single-ended signal; and a unit trace of the first signal layer includes a first signal trace (i.e., the signal trace 1041) and a first ground signal trace (i.e., the ground signal trace 1042).

[0056] It should be noted that the unit trace refers to a trace for transmitting a unit current signal. Understandably, the single-ended signal refers to a current signal transmitted by one signal trace 1041 plus one reference line (i.e., a signal return path provided by the ground layer 102). In this embodiment, after removing the ground layer 102, a first ground signal trace (i.e., the ground signal trace 1042) with the lowest impedance of the path following the first signal trace (i.e., the signal trace 1041) throughout can be arranged side by side in the same plane of the first signal trace (i.e., the signal trace 1041). Thus, when the first signal layer does not have the ground layer 102 as the return path of the single-ended signal in the first signal layer, the single-ended signal can also take the first ground signal trace with the lowest impedance of the path throughout as the return path, avoiding signal crosstalk and being beneficial to the signal quality of the printed circuit board.

[0057] In some embodiments, the signal layer 104 includes a second signal layer for transmitting a differential signal. The differential signal is commonly used in high-speed circuits, such as LVDS (low-voltage differential signal). The differential signal refers to a current signal transmitted by two signal traces 1041 plus two corresponding reference lines (i.e., two signal return paths provided by the ground layer 102).

[0058] In some embodiments, with reference to Figure 4 , the unit trace in the second signal layer includes two second signal traces (i.e., the signal trace 1041) and two second ground signal traces (i.e., the ground signal trace 1042). That is, after removing the ground layer 102, a second signal trace (i.e., the signal trace 1041) with the lowest impedance of the path following the second signal trace (i.e., the signal trace 1041) throughout can be arranged side by side in the same plane of each second signal trace (i.e., the signal trace 1041). Thus, when the second signal layer does not have the ground layer 102 as the return path of the differential signal in the second signal layer, the differential signal also follows the two second ground signal traces (i.e., the ground signal trace 1042) with the lowest impedance of the path throughout as the return path.

[0059] In some embodiments, in order to avoid the dense traces of the differential signal, resulting in signal crosstalk, with reference to Figure 5The unit trace in the second signal layer includes two second signal traces (i.e., signal traces 1041) and three second ground signal traces (i.e., ground signal traces 1042). That is, after removing the ground layer 102, not only two second signal traces (i.e., signal traces 1041) following the path with the lowest impedance of the differential signal transmitted in the middle of the two second signal traces (i.e., signal traces 1041) can be arranged side by side in the same plane, but also one second signal trace (i.e., signal trace 1041) can be additionally arranged between the two second signal traces (i.e., signal traces 1041), thereby avoiding crosstalk between the two signals in the differential signal by adding one signal return path between the two signal return paths.

[0060] In the embodiment, in order to realize miniaturization of the printed circuit board and transmit more signals, the copper thickness of the signal traces 1041 of the signal layer 104 is designed to be N microns, wherein N is a natural number greater than 1; N is related to the impedance of the signal traces.

[0061] It should be understood that the copper thickness of the signal traces 1041 in the signal layer in the prior art is usually 1 micron or 0.5 micron, that is, in the embodiment, the copper thickness of the signal traces 1041 (i.e., the line height of the signal traces 1041) is increased after removing the ground layer 102.

[0062] Further, in the embodiment, the line width of the signal traces 1041 of the signal layer 104 is less than the line width of the reference signal traces, wherein the reference signal traces are the signal traces of the ground layer 102 adjacent to the signal layer 104, and the line width of the signal traces is related to N.

[0063] In the embodiment, N is set according to the impedance requirements of each signal trace, and no limitation is made thereto.

[0064] It should be noted that the impedance in the embodiment refers to the ratio of the voltage and the current of the signal, that is, under the same voltage, the higher the impedance of the signal trace, the less the current signal flowing through, and the lower the impedance of the signal trace, the more the current signal flowing through.

[0065] It can be understood that, in the embodiment, in order to reduce the volume of the printed circuit board, after removing all the ground layers 102 in the stack of the printed circuit board, the ground signal traces 1042 following the path with the lowest impedance of the single-ended signal transmitted in the middle of the first signal traces (i.e., signal traces 1041) are arranged in the same plane of the signal traces 1041 of each signal layer 104, and therefore, in the embodiment, in order to realize more signals in the same area of the trace layer, the reference Figure 6 wherein, Figure 6The left side is the trace structure of the signal layer of the printed circuit board in the prior art, and the left side is the trace structure of the signal layer of the printed circuit board in the embodiment of the application. For example, the signal trace 1041 in the prior art is 1 ounce of copper thickness, and in the embodiment, the signal trace 1041 is increased to 4 ounces of copper thickness.

[0066] In other words, in the embodiment, compared with the prior art, the line height of each signal trace 1041 in the signal layer 104 is increased, and the line width of each signal trace 1041 in the signal layer 104 is reduced. Thus, on the one hand, the relative area between each signal trace 1041 in the signal layer 104 and the ground signal trace 1042 followed by the signal trace 1041 is increased, so that it is easier to control the impedance design of the transmission line, and on the other hand, the relative area in which the signal traces 1041 in adjacent signal layers 104 may overlap is reduced, thereby avoiding signal interference between adjacent signal layers 104.

[0067] Based on the above-provided printed circuit board, the embodiment of the application further provides a printed circuit board design method, comprising:

[0068] Removing the ground layer 102 matched with each signal layer 104 in the printed circuit board;

[0069] sequentially setting the corresponding ground signal trace 1042 for each signal trace 1041 in each signal layer 104;

[0070] The signal trace is a signal transmission path of the signal layer, and the ground signal trace is a signal return path of the signal layer.

[0071] It should be understood that the printed circuit board in the embodiment refers to a printed circuit board that needs to be optimized. Specifically, in the embodiment, the ground layer 102 matched with each signal layer 104 in the layout of the printed circuit board is removed, and then the corresponding ground signal trace 1042 is sequentially set for each signal trace 1041 in each signal layer 104 based on the design principle that the signal path provided by the ground signal trace 1042 is the lowest impedance path that the signal transmitted in the signal trace 1041 can find at its frequency.

[0072] As an implementable manner, after removing the ground layers 102 matched with the signal layers 104 in the layout of the printed circuit board, the initial design positions of the ground signal traces 1042 required to be arranged for the signal traces 1041 in the signal layers 104 can be determined according to the line traces of the signal return paths in the ground layers 102 in the original layout, then the line model of the current printed circuit board can be constructed in the PCB simulation software based on the initial design positions, after the line model is constructed, the signal transmission state of the line model is simulated by the PCB simulation software, and the design positions of the ground signal traces 1042 are adjusted according to the simulation result, until the result output by the PCB simulation software meets the current signal transmission state requirement.

[0073] The PCB simulation software refers to an engineering method of simulating the real behavior of an electronic circuit by using a mathematical model. The simulation software system can simulate the functional behavior of the circuit without the need to establish an actual circuit. Before the actual circuit is constructed, the design is simulated and verified by using the software, which can greatly improve the design efficiency. The simulation mode of the PCB simulation software is consistent with the prior art, and will not be described here. The printed circuit board design method provided in this embodiment removes the ground layers matched with the signal layers in the printed circuit board, and sequentially arranges the ground signal traces for the signal traces in the signal layers. The signal trace is the signal transmission path of the signal layer, and the ground signal trace is the signal return path of the signal layer, so that the printed circuit board is miniaturized and can transmit more signals.

[0074] In some embodiments, the sequentially arranging the ground signal traces for the signal traces in the signal layers comprises:

[0075] Reference Figure 3 In the case that the signal layer 104 is a first signal layer for transmitting a single-ended signal, a first ground signal trace (i.e., the ground signal trace 1042) is arranged side by side for a first signal trace (i.e., the signal trace 1041) in the first signal layer.

[0076] Specifically, after removing the ground layer 102, a first ground signal trace (i.e., the ground signal trace 1042) following the path with the lowest impedance for transmitting the single-ended signal throughout the first signal trace (i.e., the signal trace 1041) can be arranged side by side in the same plane as the first signal trace. In this way, when the first signal layer does not have a ground layer 102 as a return path for the single-ended signal in the first signal layer, the single-ended signal can also use the first ground signal trace following the path with the lowest impedance throughout as a return path, avoiding signal crosstalk and being beneficial to the signal quality of the printed circuit board.

[0077] Alternatively, reference Figure 4in the case that the signal layer 104 is a second signal layer for transmitting differential signals, two second ground signal lines (i.e., the ground signal lines 1042) are arranged side by side for the two second signal lines (i.e., the signal lines 1041) in the first signal layer.

[0078] Specifically, after the ground layer 102 is removed, two second signal lines (i.e., the signal lines 1041) can be arranged side by side on the same plane for each second signal line (i.e., the signal lines 1041) on the same plane of the two second signal lines (i.e., the signal lines 1041) that follow the path with the lowest impedance of the differential signal transmitted in the second signal layer, so that the differential signal also follows the two second ground signal lines (i.e., the ground signal lines 1042) as the return path.

[0079] Alternatively, referring to Figure 5 in the case that the signal layer 104 is a second signal layer for transmitting differential signals, three second ground signal lines (i.e., the ground signal lines 1042) are arranged side by side for the two second signal lines (i.e., the signal lines 1041) in the first signal layer.

[0080] Specifically, in order to avoid the dense arrangement of the differential signal lines, which causes crosstalk of the signals, after the ground layer 102 is removed, not only the two second signal lines (i.e., the signal lines 1041) that follow the path with the lowest impedance of the differential signal transmitted in the second signal layer can be arranged side by side on the same plane of the two second signal lines (i.e., the signal lines 1041), but also an additional second signal line (i.e., the signal line 1041) can be arranged between the two second signal lines (i.e., the signal lines 1041), so that by adding one signal return path between two signal return paths, crosstalk between one signal and another signal in the differential signal is avoided.

[0081] Thus, in this embodiment, after the ground layer 102 is removed, each signal is provided with an independent return path and follows the path, so that crosstalk is avoided and the signal quality is improved.

[0082] In some embodiments, the step of sequentially arranging the ground signal lines for the signal lines in the signal layers comprises:

[0083] The copper thickness of the signal lines in the signal layers is sequentially increased from M microns to N microns, wherein the N is related to the impedance of the signal lines.

[0084] Further, referring to Figure 6wherein, Figure 6 The left side in the middle is a design scheme of the signal line 1041 in the prior art, Figure 6 The right side in the middle is a design scheme of the signal line provided in the embodiment.

[0085] The embodiment increases the line height of each signal line 1041 in the signal layer 104, so as to increase the relative area between each signal line 1041 in the signal layer 104 and the ground signal line 1042 followed by the signal line 1041, and thus make it easier to control the impedance design of the transmission line.

[0086] In the embodiment, N is set according to the impedance requirement of each signal line, and no limitation is made to this.

[0087] In some embodiments, after the copper thickness of each signal line in each signal layer is increased from M microns to N microns, the method further includes:

[0088] sequentially reducing the line width of each signal line in each signal layer, wherein the line width of the signal line is related to N.

[0089] It should be noted that the impedance in the embodiment refers to the ratio of the voltage and the current of the signal, that is, under the same voltage, the higher the impedance of the signal line 1041, the less current signal will flow, and the lower the impedance of the signal line, the more current signal will flow.

[0090] In the embodiment, after the copper thickness of the signal line 1041 is increased from M microns to N microns, the line width corresponding to the signal line 1041 with the N-micron copper thickness is determined under the condition of ensuring that the impedance of the signal line 1041 remains unchanged.

[0091] Compared with the prior art, the embodiment increases the line height of each signal line 1041 in the signal layer 104 and reduces the line width of each signal line 1041 in the signal layer 104, thereby on the one hand, increasing the relative area between each signal line 1041 in the signal layer 104 and the ground signal line 1042 followed by the signal line 1041, and thus making it easier to control the impedance design of the transmission line, and on the other hand, reducing the relative area in which the signal lines 1041 between adjacent signal layers 104 may coincide, and thus avoiding signal interference between adjacent signal layers 104.

[0092] The embodiment also provides a server including the printed circuit board provided in the above embodiment. The printed circuit board as a matching part of the server achieves the purpose of miniaturization and arrangement of more signal lines for signal transmission, and thus can improve the overall electrical performance of the server.

[0093] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the same; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A printed circuit board, characterized by, The printed circuit board comprises: a plurality of signal layers, signal traces arranged in each of the signal layers, and ground signal traces corresponding to the signal traces; wherein the signal traces are signal transmission paths of the signal layers, and the ground signal traces are signal return paths of the signal layers; the signal path provided by the ground signal traces is a path with the lowest impedance of signals transmitted in the signal traces at a frequency of the signals; the signal layers comprise a first signal layer for transmitting single-ended signals; a unit trace in the first signal layer comprises one first signal trace and one first ground signal trace; the signal layers comprise a second signal layer for transmitting differential signals; a unit trace in the second signal layer comprises two second signal traces and two second ground signal traces; or a unit trace in the second signal layer comprises two second signal traces and three second ground signal traces.

2. The printed circuit board of claim 1, wherein, A copper thickness of the signal traces of the signal layers is N microns, wherein the N is a natural number greater than 1; the N is related to an impedance of the signal traces.

3. The printed circuit board of claim 2, wherein, A line width of the signal traces of the signal layers is smaller than a line width of a reference signal trace, wherein the reference signal trace is a signal trace of a ground layer adjacent to the signal layer and provided with a signal return path; the line width of the signal traces is related to the N.

4. A printed circuit board design method applied to the printed circuit board according to any one of claims 1 to 3, characterized by, The printed circuit board comprises: removing a ground layer matched with each of the signal layers in a printed circuit board; sequentially arranging corresponding ground signal traces for each of the signal traces in each of the signal layers; wherein the signal traces are signal transmission paths of the signal layers, and the ground signal traces are signal return paths of the signal layers; the signal path provided by the ground signal traces is a path with the lowest impedance of signals transmitted in the signal traces at a frequency of the signals; the sequentially arranging corresponding ground signal traces for each of the signal traces in each of the signal layers comprises: in a case where the signal layer is a first signal layer for transmitting single-ended signals, arranging one first ground signal trace side by side for a first signal trace in the first signal layer; or in a case where the signal layer is a second signal layer for transmitting differential signals, arranging two second ground signal traces side by side for two second signal traces in the first signal layer; or in a case where the signal layer is a second signal layer for transmitting differential signals, arranging three second ground signal traces side by side for two second signal traces in the first signal layer.

5. The printed circuit board design method of claim 4, wherein, the sequentially arranging corresponding ground signal traces for each of the signal traces in each of the signal layers comprises: sequentially increasing a copper thickness of each of the signal traces in each of the signal layers from M microns to N microns, wherein the N is related to an impedance of the signal traces.

6. The printed circuit board design method of claim 5, wherein, after the sequentially increasing the copper thickness of each of the signal traces in each of the signal layers from M microns to N microns, the method further comprises: sequentially decreasing a line width of each of the signal traces in each of the signal layers, wherein the line width of the signal traces is related to the N.

7. A server, characterized by The printed circuit board comprises any one of claims 1 to 3.

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