Differential signal line, design method thereof and circuit board

Abstract

The invention relates to a differential signal line, a design method thereof and a circuit board. The method comprises the following steps: determining a to-be-adjusted wire in the differential signal line and an initial winding section of the to-be-adjusted wire; based on the simulation model, obtaining the time delay of transmitting the electric signal by the initial winding section; cutting off part of the initial winding section according to the time delay, and connecting the equivalent line segment at the cutting position to form a target winding section; according to the to-be-adjusted wire in the differential signal wire and the first signal wire, at least one target winding section is formed in the to-be-adjusted wire, and at least one compensation wire section is correspondingly added in the to-be-adjusted wire, so that a tangent compensation mode can be adopted to compensate the time delay caused by the initial winding section, and the differential signal can be propagated isochronous by the differential signal.

Description

Technical Field

[0001] The present application relates to the technical field of differential signal lines, and particularly to a differential signal line, a design method thereof, and a circuit board. Background Art

[0002] With the rapid development of the communication industry, the speed of high-speed differential signals is getting higher and higher. For higher speeds, there has emerged a four-level pulse amplitude modulation (PAM4) signal mode. Since a differential signal refers to a signal transmitted by two lines, and what is transmitted is the voltage difference between the two signals, while the PAM4 signal technology is a modulation technology that uses four different signal levels to transmit signals, and it requires the positive signal (P) and the negative signal (N) in the differential signal to reach the receiving end at equal times.

[0003] In related technologies, the short lines in the differential signal lines are wound around to make the total lengths of the differential signal lines equal to achieve the purpose of equal time. However, for the differential signal lines after winding, their propagation paths will be different, and even if the total lengths of the signal lines are equal, the purpose of equal-time propagation of electrical signals cannot be achieved. Summary of the Invention

[0004] Based on this, it is necessary to provide a differential signal line, a design method thereof, and a circuit board, which can adopt a tangent compensation method to compensate for the delay caused by the initial winding segment, so that the differential line signal can propagate the differential signal in equal time.

[0005] An embodiment of the present application provides a design method for a differential signal line, including:

[0006] Determine the trace to be adjusted in the differential signal line and the initial winding segment of the trace to be adjusted;

[0007] Obtain the delay of the electrical signal transmitted by the initial winding segment based on a simulation model;

[0008] Cut off a part of the initial winding segment according to the delay, and connect an equivalent segment at the cut-off position to form a target winding segment; the simulation model has no response to the equivalent segment, and the line length of the equivalent segment is the same as that of the cut-off part of the initial winding segment;

[0009] Form at least one target winding segment according to the trace to be adjusted in the differential signal line and the first signal trace in the trace to be adjusted, and correspondingly add at least one compensation segment in the trace to be adjusted, the line length of the compensation segment is the same as that of the equivalent segment, and the number of the compensation segments is the same as that of the target winding segments.

[0010] In one embodiment, the step of removing a part of the initial winding segment according to the time delay includes:

[0011] Determining a time-delay line length corresponding to the time delay according to the time delay and a preset conversion relationship;

[0012] Removing a sub-segment of the initial winding segment, where the line length of the sub-segment is the same as the time-delay line length.

[0013] In one embodiment, the step of connecting an equivalent line segment at the removal position to form a target winding segment includes:

[0014] Laying a copper foil at the removal position to form a target winding segment; wherein, the copper foil is electrically connected to the remaining initial winding segment respectively, and the line width of the copper foil is the same as the line width of the sub-segment.

[0015] In one embodiment, the initial winding segment includes a first sub-segment, a second sub-segment and a third sub-segment connected in sequence, the second sub-segment is arranged in parallel with a segment of the non-initial winding segment in the to-be-adjusted trace, and the removal position is located in the second sub-segment.

[0016] In one embodiment, the differential signal line includes the to-be-adjusted trace and a first signal trace, and the line length of the first signal trace is greater than the line length of the to-be-adjusted trace, wherein,

[0017] The line width of the initial winding segment of the to-be-adjusted trace is greater than the line width of the segment of the non-initial winding segment in the to-be-adjusted trace;

[0018] The line width of the relative segment of the first signal trace opposite to the initial winding segment is the same as the line width of the initial winding segment.

[0019] In one embodiment, the step of correspondingly adding at least one compensation segment in the to-be-adjusted trace includes:

[0020] Determining a compensation position of the compensation segment in each target winding segment;

[0021] Adding the compensation segment at the compensation position, and the compensation segment is used to increase the winding height of the target winding segment.

[0022] In one embodiment, the compensation position is located in at least one of the first sub-segment and the third sub-segment.

[0023] In one embodiment, the step of forming at least one target winding segment in the to-be-adjusted trace according to the to-be-adjusted trace and the first signal trace in the differential signal line includes:

[0024] Determine the number of the target winding segments according to the line length difference between the to-be-adjusted trace and the first signal trace;

[0025] When the number is at least two, form at least two of the target winding segments in the to-be-adjusted trace, wherein the distance between two adjacent target winding segments arranged adjacent to each other is greater than or equal to the width of the target winding segment.

[0026] An embodiment of the present application further provides a differential signal line, which is prepared by using the design method of the foregoing differential signal line.

[0027] An embodiment of the present application further provides a circuit board, including a substrate and the foregoing differential signal line disposed on the substrate.

[0028] The foregoing differential signal line, its design method and circuit board determine the initial winding segments of the to-be-adjusted trace in the differential signal line; obtain the delay of the electrical signal transmitted by the initial winding segments based on the simulation model; cut off part of the initial winding segments according to the delay, and connect equivalent segments at the cut-off positions to form target winding segments; form at least one target winding segment in the to-be-adjusted trace according to the to-be-adjusted trace and the first signal trace in the differential signal line, and correspondingly add at least one compensation segment in the to-be-adjusted trace. By this kind of tangent compensation method, the delay brought by the initial winding segments can be offset. In addition, by setting the compensation segments to compensate for the line length of the part of the initial winding segments cut off, the isochronous propagation of the differential signals transmitted by the differential line signals can be realized, and further the transmission quality of the electrical signals in the differential signal line can be improved, and the reliability of the product can be enhanced. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a flowchart of the design method of the differential signal line provided by the embodiment of the present application;

[0031] Figure 2 It is a schematic structural diagram of the differential signal line with initial winding segments provided by the embodiment of the present application;

[0032] Figure 3 It is a schematic structural diagram of the differential signal line corresponding to the design method of the differential signal line provided by the embodiment of the present application;

[0033] Figure 4 It is a schematic structural diagram of the differential signal line with initial winding segments provided by another embodiment of the present application;

[0034] Figure 5 provided for the embodiments of the present application;

[0035] Figure 6 Schematic diagram of the differential signal line with a target winding segment provided for the embodiments of the present application;

[0036] Figure 7 Flow chart of the design method of the differential signal line provided for another embodiment of the present application;

[0037] Figure 8 Schematic diagram of the differential signal line with a target winding segment provided for another embodiment of the present application;

[0038] Figure 9 Schematic diagram of the differential signal line with a target winding segment provided for yet another embodiment of the present application;

[0039] Figure 10 Schematic diagram of the differential signal line with a target winding segment provided for still another embodiment of the present application;

[0040] Figure 11 as Figure 10 shown, simulation result diagram of the differential signal line;

[0041] Figure 12 Schematic diagram of the differential signal line in the related art;

[0042] Figure 13 as Figure 12 shown, simulation result diagram of the circuit board;

[0043] Explanation of the reference numerals in the drawings:

[0044] 110 - trace to be adjusted; 111 - initial winding segment; 112 - straight segment of the trace to be adjusted;

[0045] 101 - sub - segment; 103 - copper foil; first sub - segment; B - second sub - segment; C - third sub - segment;

[0046] 120 - first signal trace; 121 - relative segment; 122 - non - relative segment 122;

[0047] 31 - first signal line; 32 - second signal line; 301 - convex hull of the first signal line. Detailed implementation manners

[0048] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0049] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the accompanying drawings. These are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present application.

[0050] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0051] In the present application, unless otherwise clearly specified and limited, terms such as "install", "connect", "electrically connect", "fix", etc. should be understood in a broad sense. For example, it can be a fixed electrical connection, a detachable electrical connection, or integrated; it can be a mechanical electrical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0052] In this application, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may mean 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 being "above", "over" and "on top of" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply indicates that the horizontal height of the first feature is greater than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply indicates that the horizontal height of the first feature is less than that of the second feature.

[0053] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "electrically connected to" another element, it can be directly electrically connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only implementation.

[0054] As Figure 1 shown, in an exemplary embodiment, the present application provides a design method for differential signal lines, including the following steps 102 to step 108.

[0055] Step 102, determine the trace to be adjusted in the differential signal line and the initial winding segment of the trace to be adjusted.

[0056] As Figure 2 shown, the differential signal includes the trace 110 to be adjusted and the first signal trace 120, wherein the line length of the trace 110 to be adjusted is less than the line length of the first signal trace 120. One of the trace 110 to be adjusted and the first signal trace 120 is the P signal line for transmitting the positive signal P in the differential signal line, and one of the trace 110 to be adjusted and the first signal trace 120 is the N signal line for transmitting the negative signal N in the differential signal line.

[0057] Since the line length of the trace to be adjusted is less than the line length of the first signal trace, in order to achieve the equal-length design of the differential signal, it is necessary to wind the trace to be adjusted. Exemplarily, an initial winding segment 111 can be designed in the trace to be adjusted, and the initial winding segment 111 can protrude relative to other segments (e.g., straight segments) of the trace to be adjusted.

[0058] In the embodiments of the present application, the initial winding segment 111 can be referred to as a convex hull. Exemplarily, the initial winding segment 111 can respectively include a zigzag winding segment formed by multiple straight segments, or a winding segment composed of straight segments and curved segments, or can also be a curved winding segment. In the embodiments of the present application, the specific shape of the initial winding segment 111 is not limited.

[0059] Step 104: Obtain the delay of the initial winding segment for transmitting an electrical signal based on the simulation model.

[0060] The simulation model can include a passive S-parameter model, etc., which can realize the performance simulation model of differential signal lines. Exemplarily, by constructing a differential signal line in the simulation model, which includes a to-be-adjusted trace and a first trace, wherein, the to-be-adjusted trace includes an initial winding segment, and the total line length of the to-be-adjusted trace is the same as the total line length of the first trace. Based on the simulation module, the transmission duration of the differential signal in the to-be-adjusted trace and the first signal trace can be determined, and then the delay of the initial winding segment for transmitting an electrical signal can be obtained. The delay can be the difference between a first duration and a second duration. Wherein, the first duration is the duration for the first signal trace to transmit an electrical signal, and the second duration is the duration for the to-be-adjusted trace to transmit an electrical signal. It should be noted that the delay magnitudes of initial winding segments with different shapes are different.

[0061] Step 106: Cut off a part of the initial winding segment according to the delay, and connect an equivalent segment at the cut-off position to form a target winding segment.

[0062] The delay corresponding to the initial winding segment is related to the line length. For example, the delay is positively correlated with the line length. The greater the delay, the greater the corresponding line length. In an exemplary embodiment, the line length of the initial winding segment to be cut off can be determined based on the delay, and then this part of the initial winding segment is cut off. The cut-off part of the initial winding segment affects the transmission duration of the electrical signal.

[0063] At the corresponding position of the cut-off part of the initial winding segment, an equivalent segment is correspondingly added to form the target winding segment of the to-be-adjusted trace. The equivalent segment can be electrically connected to the remaining initial winding segment. Wherein, the line length of the added equivalent segment is the same as the line length of the cut-off part of the initial winding segment. In addition, the simulation model has no response to the equivalent segment. In other words, the simulation model cannot recognize the equivalent segment, and the line length of the equivalent segment cannot be recognized by the simulation model. The total line length of the to-be-adjusted trace recognized by the simulation software is the total line length excluding the equivalent segment.

[0064] Step 108: According to the to-be-adjusted trace and the first signal trace in the differential signal line, form at least one target winding segment in the to-be-adjusted trace, and correspondingly add at least one compensation segment in the to-be-adjusted trace.

[0065] The number of target winding segments in the trace to be adjusted can be determined according to the line length difference between the trace to be adjusted and the first signal trace, as well as the total winding length of the target winding segment. Exemplarily, the number of target winding segments can be 1, or 2, 3, or more.

[0066] In addition to forming the corresponding number of target winding segments in the trace to be adjusted, at least one compensation segment needs to be correspondingly added to supplement the line length of the removed part of the initial winding segment. In the embodiments of the present application, the trace to be adjusted with the corresponding number of compensation segments added can be referred to as the second signal trace. In this way, the first signal trace and the second signal trace can form a differential signal line. The line length of the compensation segment is the same as that of the equivalent segment, and the number of compensation segments is the same as that of the target winding segments. Exemplarily, if the line length of the equivalent segment corresponding to an initial winding segment is 2.3 mil, the line length of the compensation segment is also 2.3 mil. If there is one target winding segment on the trace to be adjusted, an equivalent segment with a length of 2.3 mil can be added to the trace to be adjusted. If there are two target winding segments on the trace to be adjusted, two equivalent segments with a length of 2.3 mil can be added to the trace to be adjusted. The two equivalent segments with a length of 2.3 mil can be continuously arranged on the trace to be adjusted, or can be arranged at intervals in multiple segments on the trace to be adjusted. Exemplarily, the two equivalent segments can be divided into four sub-segments arranged at intervals on the trace to be adjusted. In the embodiments of the present application, the specific setting method and position of the compensation segments in the trace to be adjusted are not specifically limited, nor are they limited to the above examples.

[0067] In the design method of the differential signal line in this embodiment, it can determine the initial winding segment of the trace to be adjusted in the differential signal line; obtain the delay of the electrical signal transmitted by the initial winding segment based on the simulation model; cut off a part of the initial winding segment according to the delay, and connect an equivalent segment at the cut-off position to form a target winding segment; form at least one target winding segment in the trace to be adjusted according to the trace to be adjusted and the first signal trace in the differential signal line, and correspondingly add at least one compensation segment in the trace to be adjusted, that is, the delay of the initial winding segment can be obtained, and a part of the initial winding segment affecting the delay can be cut off according to the delay, and then an equivalent segment with the corresponding line length can be additionally added in the trace to be adjusted. Through this kind of tangent compensation method, the delay brought by the initial winding segment can be compensated. In addition, by setting the compensation segment to compensate the line length of the cut-off part of the initial winding segment, the isochronous propagation of the differential signal in the differential signal line is realized, and further the transmission quality of the electrical signal in the differential signal line can be improved, and the reliability of the product can be enhanced.

[0068] In an exemplary embodiment, cutting off a part of the initial winding segment according to the delay includes: determining the line length corresponding to the delay according to the delay and the preset conversion relationship, and the step of cutting off the sub-segment of the initial winding segment.

[0069] Exemplarily, the simulation model can also simulate the to-be-adjusted trace including 2 initial winding segments and the first signal trace, and the simulation results are shown in Table 1.

[0070] Table 1 shows the delay results of the simulation model for the to-be-adjusted trace with 2 convex hulls.

[0071]

[0072] Please continue to refer to Figure 2 , in Table 1, W represents the line width of the to-be-adjusted trace and the first signal trace, 3W represents the shortest distance between the center of the to-be-adjusted trace and the center of the first signal trace. S represents the inner pitch of the differential pair, that is, the shortest distance between the center of the adjusted trace and the center of the first signal trace, n*S represents the winding height of the initial winding segment, that is, the distance between the farthest position of the initial winding segment and the first signal trace, and n is 3.5, 2.6, 1.7, 0.9. That is, Table 1 simulates the delay of different formed initial winding segments. In the embodiment of the present application, an example of the initial winding segment with a simulation CASE of 3W2.6S is used for illustration. The delay corresponding to an initial winding segment of 3W2.6S is 0.35 ps.

[0073] The preset conversion relationship can be used to characterize the corresponding relationship between the delay and the delay line length. For example, a delay of 1 ps corresponds to a delay line length of 6 mil. Based on the preset conversion relationship, the delay line length corresponding to an initial winding segment of 3W2.6S (with a delay of 0.35 ps) is 2.3 mil. As Figure 3 described, for the initial winding segment of 3W2.6S, a part of the initial winding segment that affects the delay with a length of 2.3 mil can be cut off. For the sake of convenience of explanation, the part of the initial winding segment that needs to be cut off is called sub-segment 101. In other words, the line length of sub-segment 101 is the delay line length, such as 2.3 mil.

[0074] Based on this embodiment, in an exemplary embodiment, an equivalent segment is connected at the cutting position to form a target winding segment, including: the step of pasting a copper foil at the cutting position to form the target winding segment.

[0075] Please continue to refer to Figure 3 , where the copper foil 103 can be used as the equivalent segment. The copper foil 103 is arranged at the switching position of the sub-segment 101 and is electrically connected to the remaining initial winding segments respectively. The line width of the copper foil 103 is the same as the line width of the sub-segment 101, and the line length of the copper foil 103 is the same as the line length of the aforementioned sub-segment 101. In this way, by using the copper foil 103 to replace the sub-segment 101, the simulation model cannot recognize the line length of the copper foil 103. In this way, the influence of the sub-segment on the delay can be ignored to achieve the isochronous propagation of the electrical signal in the differential signal line.

[0076] Please continue to refer to Figure 2 , in an exemplary embodiment, the initial winding segment 111 includes a first sub-segment A, a second sub-segment B, and a third sub-segment C connected in sequence. The second sub-segment B is arranged in parallel with the segment of the to-be-adjusted trace 110 that is not the initial winding segment.

[0077] Exemplarily, for the sake of convenience of description, an example is given where the to-be-adjusted trace 110 includes an initial winding segment 111 and a straight segment 112. Among them, the segment of the to-be-adjusted trace 110 that is not the initial winding segment can be the straight segment 112. That is, the second sub-segment B in the initial winding segment 111 is arranged in parallel with the straight segment 112. In this initial winding segment 111, the line length of its second sub-segment B will affect the magnitude of the delay. Therefore, the sub-segment to be cut can be set in the second sub-segment B, that is, the sub-segment is located in the second sub-segment B.

[0078] Exemplarily, the included angle between the first sub-segment A and the second sub-segment B in the initial winding segment 111 is a first obtuse angle, and the included angle between the third sub-segment C and the second sub-segment B is also a second obtuse angle. Among them, the first obtuse angle and the second obtuse angle can be the same or different. Optionally, the line lengths of the first sub-segment A and the third sub-segment C can be the same or different. In the embodiments of the present application, an example is given where the line lengths of the first sub-segment A and the third sub-segment C are the same, and the first obtuse angle and the second obtuse angle are the same.

[0079] As Figure 4 shown, in an exemplary embodiment, the line width of the initial winding segment 111 of the to-be-adjusted trace 110 is greater than the line width of the segment of the to-be-adjusted trace 110 that is not the initial winding segment; the line width of the segment of the first signal trace 120 that is arranged opposite to the initial winding segment 111 is the same as the line width of the initial winding segment 111.

[0080] It can be understood that the to-be-adjusted trace 110 includes an initial winding segment 111 and a straight segment 112. Among them, the line width of the straight segment 112 is w1, and the line width of the initial winding segment 111 is w2, where w2 > w1. Among them, the first signal trace 120 includes an opposite segment 121 arranged opposite to the initial winding segment, and a non-opposite segment 122. The line width of the non-opposite segment 122 is w3, and the line width of the opposite segment 121 is w4, where w4 > w3, and w1 = w3, w2 = w4.

[0081] By adjusting the line width of the initial winding segment and the line width of the opposite segment in the first signal trace, the impedance of the corresponding trace can be adjusted so that the impedance of the to-be-adjusted trace segment is equal to half of the differential line target impedance, and the impedance of the first signal trace is equal to half of the differential line target impedance. Exemplarily, the differential line target impedance is 100Ω, and the impedances of the to-be-adjusted trace segment and the first signal trace are 50Ω.

[0082] In an exemplary embodiment, the ratio range of the line width w2 of the initial winding segment to the line width w1 of the straight segment is 1.05 - 1.2. For example, the ratio of the line width w2 of the initial winding segment to the line width w1 of the straight segment can be 1.05, 1.1, 1.15, or 1.2, etc.

[0083] In this embodiment, by designing the line width of the initial winding segment and the widening of the relative segments in the first signal trace, the influence of the increased distance between the initial winding segment and the first signal trace on the differential impedance of the to-be-adjusted trace segment and the first signal trace can be eliminated, ensuring the consistency of the differential impedance of the to-be-adjusted trace segment and the first signal trace, so as to improve the transmission quality of the electrical signal and enhance the reliability of the product.

[0084] As Figure 5 shown, in an exemplary embodiment, at least one compensation segment is correspondingly added in the to-be-adjusted trace, including step 502 - step 504.

[0085] Step 502, determine the compensation position of the compensation segment in each target winding segment.

[0086] Step 504, add a compensation segment at the compensation position, and the compensation segment is used to increase the winding height of the target winding segment.

[0087] The compensation segment does not affect the magnitude of the delay, that is, the compensation segment has no influence on the delay. Based on the simulation model, it is found by simulating the initial winding segment that changing the winding height of the initial winding segment has no influence on the delay. Therefore, it can be determined that the compensation position of the compensation segment is the position that affects the winding height. The winding height can be understood as the protruding height of the convex hull. For the sake of convenience of explanation, the protruding height is the shortest distance between the highest point segment in each winding segment and the corresponding straight segment. For example, the protruding height can be the shortest distance between the wire core of the highest point segment and the wire core of the corresponding straight segment.

[0088] In an exemplary embodiment, the winding height of the target winding segment after adding the compensation segment is 1 - 4 times the inner spacing of the differential pair.

[0089] In this embodiment, by setting the winding height of the target winding segment, the protruding height of the target winding segment after adding the compensation segment can be avoided from being too high, so as to save the occupied area of the to-be-adjusted trace.

[0090] In an exemplary embodiment, the compensation position is located in at least one of the first sub-segment and the third sub-segment. Exemplarily, if there is one target winding segment, there is also one compensation segment. This compensation segment can compensate (i.e., be located in) the first sub-segment, or this compensation segment can compensate the third sub-segment, or this compensation segment evenly compensates the target winding segment. That is, the compensation segment can be evenly divided into a first compensation sub-segment and a second compensation sub-segment. The first compensation sub-segment compensates the first sub-segment, and the second compensation sub-segment compensates the third sub-segment. Please continue to refer to Figure 3 . Figure 3 In Figure 3 , after adding a compensation segment to the target winding segment, its winding height can increase by Δh.

[0091] Exemplarily, if there are two target winding segments (for example, a first target winding segment and a second target winding segment), there are also two compensation segments (for example, a first compensation segment and a second compensation segment). Among them, the first compensation segment evenly compensates the first target winding segment, and the second compensation segment evenly compensates the second target winding segment.

[0092] In this embodiment, by positioning the compensation position of the compensation segment in the target winding segment, it can avoid the problem of impedance mutation caused by the compensation segment being located in the straight segment, effectively reduce the reflection of high-speed signals, and improve the signal quality. In addition, the compensation segment is only used to increase the height of the target winding segment and does not affect the delay brought by the target winding segment. It can compensate the line length of the cut-off sub-segment. Through this kind of tangent compensation method, it can compensate the delay brought by the initial winding segment, realize the isochronous propagation of differential signals in differential line signal transmission, and further improve the transmission quality of electrical signals in differential signal lines and enhance the reliability of products.

[0093] In an exemplary embodiment, forming at least one target winding segment in the to-be-adjusted trace and the first signal trace in the differential signal line includes: determining the number of target winding segments according to the line length difference between the to-be-adjusted trace and the first signal trace, and forming at least two target winding segments in the to-be-adjusted trace when the number is at least two.

[0094] The shape and winding length of the target winding segment are the same as those of the initial winding segment in the foregoing embodiment. The difference between the target winding segment and the initial winding segment is that the equivalent segment in the target winding segment replaces the sub-segment of the initial segment. In this way, the winding length of the target winding segment is determined. Among them, the line length difference between the to-be-adjusted trace and the first signal trace is the difference between the line length of the first signal trace and the line length of the adjusted trace (without the initial winding segment). Based on this line length difference and the winding length of the target winding segment, the number of target winding segments can be determined. For example, the ratio of the difference between the line length difference and the winding length is positively correlated with the number. If the ratio range is between 1 and 2, the number of target winding segments can be determined to be 1.

[0095] In an exemplary embodiment, as Figure 6 shown, the distance L between two adjacent target winding segments is greater than or equal to the width D of the target winding segment. The target winding segment can be understood as the distance between the first connection point and the second connection point. The first connection point is the connection point of the first sub-segment and the straight segment, and the second connection point is the connection point of the third sub-segment and the straight segment.

[0096] In this embodiment, by setting the distance between two adjacent target winding segments, the situation that the distance between two target winding segments is too close can be avoided, so the situation that the impedance discontinuity points are too close can be avoided, thereby improving the transmission quality of the electrical signal and enhancing the reliability of the product.

[0097] As Figure 7 shown, in an exemplary embodiment, the embodiment of the present application also provides a design method for differential signal lines, which specifically includes Step 1 - Step 6.

[0098] Step 1: Find the short line in the PN differential line (for example, the trace to be adjusted), and wind out a T-shaped convex hull (for example, the initial winding segment), refer to Figure 3 .

[0099] Step 2: Thicken the width of the line that is not coupled to the T-shaped convex hull until the single-line target impedance is equal to half of the differential line target impedance, refer to Figure 4 .

[0100] Step 3: Determine the delay corresponding to the T-shaped convex hull through the simulation model and convert it into the corresponding delay line length. Among them, each T-shaped convex hull corresponds to a delay of 0.35 ps, and its conversion to the delay line length is 2.3 mil.

[0101] Step 4: Cut off 2.3 mil of the trace on the T-shaped convex hull, and then draw a static copper foil to stick on the line to connect the two sides of the trace, and the width is the same as the line width to form a target winding segment, as Figure 8 shown.

[0102] Step 5: Copy one or more target winding segments (T-shaped convex hulls, including copper foils) completed in the above steps and connect them to the short line until the line length of the short line ≥ the line length of the long line (for example, the first signal trace), as Figure 9 shown.

[0103] Step 6: When the line length of the short line is much longer than that of the long line, the height of the target winding segment (T-shaped convex hull, including copper foil) can be appropriately adjusted.

[0104] The design method of differential signal lines in this embodiment can obtain the delay of the initial winding segment, cut off the part of the initial winding segment that affects the delay according to the delay, and additionally add a compensation segment with a corresponding line length to the to-be-adjusted trace. Through this kind of tangent compensation method, the delay brought by the initial winding segment is compensated, and the isochronous propagation of differential signals in the differential signal lines is realized. Furthermore, the transmission quality of electrical signals in the differential signal lines can be improved, and the reliability of the product can be enhanced.

[0105] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are displayed in sequence according to the arrows, these steps do not necessarily need to be executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages do not necessarily need to be executed at the same time, but can be executed at different times. The execution order of these steps or stages does not necessarily need to be sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0106] Based on the same inventive concept, the embodiment of the present application also provides a design device for implementing the design method of the differential signal lines involved above. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the design device provided below can refer to the limitations on the design method of the differential signal lines in the above text, and will not be repeated here.

[0107] In an exemplary embodiment, a design device is provided, including: a determination module, an acquisition module, an update module, and a design module, where:

[0108] The determination module is configured to determine the to-be-adjusted trace in the differential signal line and the initial winding segment of the to-be-adjusted trace.

[0109] The acquisition module is configured to obtain the delay of the electrical signal transmitted by the initial winding segment based on the simulation model.

[0110] The update module is configured to cut off a part of the initial winding segment according to the delay and connect an equivalent segment at the cut-off position to form a target winding segment; the simulation model has no response to the equivalent segment, and the equivalent segment has the same line length as the cut-off part of the initial winding segment;

[0111] The design module forms at least one of the target winding segments in the to-be-adjusted trace according to the to-be-adjusted trace and the first signal trace in the differential signal traces, and correspondingly adds at least one compensation segment in the to-be-adjusted trace. The line length of the compensation segment is the same as that of the equivalent segment, and the number of the compensation segments is the same as that of the target winding segments.

[0112] Each module in the above design device can be implemented in whole or in part by software, hardware, and their combination. Each of the above modules can be embedded in the processor in the computer device in the form of hardware or be independent of the processor, or can be stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0113] In an exemplary embodiment, the present application further provides a computer device, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps in any one of the embodiments of the above design method of the differential signal traces are implemented.

[0114] In an exemplary embodiment, the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by the processor, the steps in any one of the embodiments of the above design method of the differential signal traces are implemented.

[0115] In an exemplary embodiment, the present application further provides a computer program product, including a computer program. When the computer program is executed by the processor, the steps in any one of the embodiments of the above design method of the differential signal traces are implemented.

[0116] In an exemplary embodiment, the present application further provides a differential signal trace, which is prepared by using the design method of the differential signal trace in any of the above embodiments.

[0117] Exemplarily, the differential signal trace includes a first signal trace and a second signal trace, wherein the second signal trace is the to-be-adjusted trace including at least one target winding segment in any of the foregoing embodiments.

[0118] Figure 10 It is a differential signal trace prepared by the design method of the differential signal trace provided in the embodiment of the present application. Based on the differential signal trace as Figure 10 shown, the S-parameter model is extracted through source simulation, and the Inter-pair Skew index of the differential signal is read. The result is as Figure 11 shown.

[0119] As Figure 12As shown, in the related art, a differential signal line includes a first signal line 31 and a second signal line 32. Among them, the first signal line 31 includes a plurality of convex hulls 301 arranged at intervals, the second signal line 32 is not provided with convex hulls, and the total lengths of the first signal line 31 and the second signal line 32 are the same. Based on the Figure 12 shown differential signal line, the S-parameter model is extracted through source simulation, and the Inter-pair Skew index of the differential signal is read. The result is as Figure 13 shown.

[0120] Based on the Figure 11 and Figure 13 simulation results, it can be known that the Inter-pair Skew index of the differential signal line provided by the embodiment of the present application is improved by 1.6 ps compared with that of the differential signal line in the related art, and the Inter-pair Skew index of the differential signal line provided by the embodiment of the present application is 0.2 ps, which is close to 0, and its Inter-pair Skew has an obvious improvement.

[0121] In an exemplary embodiment, the present application further provides a circuit board, which includes a substrate and a differential signal line disposed on the substrate.

[0122] Exemplarily, the substrate may include a printed circuit board (PCB), and the printed circuit board may be a single-layer PCB board or a multi-layer PCB board. The differential line structure in any of the foregoing embodiments may be located on any layer of the PCB board.

[0123] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0124] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for designing a differential signal line, characterized in that: include: Determine a routing line to be adjusted in a differential signal line, and an initial winding segment of the routing line to be adjusted; Obtaining the delay of the initial winding segment transmitting the electrical signal based on the simulation model; Cutting off part of the initial winding segment according to the delay, and connecting an equivalent line segment at the cut-off position to form a target winding segment; the simulation model has no response to the equivalent line segment, and the equivalent line segment has the same length as the cut-off part of the initial winding segment; At least one target winding segment is formed in the routing to be adjusted according to the routing to be adjusted in the differential signal line and the first signal routing, and at least one compensation segment is correspondingly added to the routing to be adjusted, the length of the compensation segment is the same as the length of the equivalent segment, and the number of the compensation segments is the same as the number of the target winding segments.

2. The method according to claim 1, characterized in that: The method of cutting off part of the initial winding segment according to the delay comprises: Determine the delay line length corresponding to the delay according to the delay and the preset conversion relationship; A sub-segment of the initial winding segment is cut off, and the length of the sub-segment is the same as the length of the delay line.

3. The method according to claim 2, characterized in that The step of connecting the equivalent line segments at the cut-off position to form the target winding segment comprises: A copper sheet is attached at the position of the cutting position to form a target winding segment; wherein the copper sheet is electrically connected to the remaining initial winding segments respectively, and the line width of the copper sheet is consistent with the line width of the sub-segment.

4. The method according to claim 3, characterized in that The initial winding segment includes a first sub-segment, a second sub-segment and a third sub-segment connected in sequence, the second sub-segment is arranged in parallel with the line segment of the routing to be adjusted that is not the initial winding segment, and the cutting position is located in the second sub-segment.

5. The method according to claim 4, characterized in that The differential signal line includes the line to be adjusted and a first signal line, the line length of the first signal line is greater than the line length of the line to be adjusted, wherein: The line width of the initial winding segment of the routing line to be adjusted is greater than the line width of the non-initial winding segment in the routing line to be adjusted; The line width of the relative line segment arranged opposite to the initial winding line segment in the first signal routing is the same as the line width of the initial winding line segment.

6. The method according to claim 4, characterized in that The step of adding at least one compensation line segment to the line to be adjusted includes: Determining a compensation position of a compensation line segment in each of the target winding segments; The compensation line segment is added at the compensation position, and the compensation line segment is used to increase the winding height of the target winding segment.

7. The method according to claim 6, characterized in that The compensation position is located at at least one of the first subsection and the third subsection.

8. The method according to claim 1, characterized in that: The forming at least one target winding segment in the routing line to be adjusted according to the routing line to be adjusted in the differential signal line and the first signal routing line comprises: Determine the number of the target winding segments according to the line length difference between the line to be adjusted and the first signal line; When the number is at least two, at least two target winding segments are formed in the routing to be adjusted, wherein a spacing between two adjacent target winding segments is greater than or equal to a width of the target winding segment.

9. A differential signal line, characterized in that: The differential signal line is manufactured by using the design method of the differential signal line as described in any one of claims 1 to 8.

10. A circuit board, characterized in that: It includes a substrate, and a differential signal line as claimed in claim 9 arranged on the substrate.

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