Signal transmission circuit, design method and server

Abstract

The invention discloses a signal transmission circuit, a design method and a server, relates to the field of signal processing, and solves the problems of signal crosstalk and interference in current signal transmission. The signal transmission circuit is introduced into an adapter plate, the adapter plate comprises a plurality of input pins, a ground pin and output pins, and the input pins are connected with the output pins through signal wires; according to the adapter plate, the arrangement mode of the signal wires, the input pins and the ground pins is optimized according to the frequency and the importance degree of transmission signals, meanwhile, the newly added ground pins in the adapter plate provide backflow paths for other signals, electromagnetic radiation can be restrained, and the risk of crosstalk and electromagnetic interference between the signals can be reduced. Therefore, the signal transmission circuit provided by the invention can reduce the generation of electromagnetic interference, effectively reduce the crosstalk between signals, and ensure the accurate transmission of the signals.

Description

Technical Field

[0001] The present invention relates to the field of signal processing, and in particular to a signal transmission circuit, a design method and a server. Background Art

[0002] Electromagnetic interference is a serious and growing form of environmental pollution, and radiated disturbance is the most important form of electromagnetic interference. It directly radiates electromagnetic energy in the form of electromagnetic waves, causing harm and interference to the human body and other equipment. Cables are the main factor causing electromagnetic compatibility problems in the system because there are large distributed capacitance and mutual inductance in conductive cables, which will cause crosstalk between cable signals.

[0003] At present, the connection method between the motherboard and other control circuit boards is: the various pins on the motherboard are brought out through the motherboard connector, one end of the cable is connected to the various pins of the motherboard connector, and the other end of the cable is connected to its corresponding control circuit board. However, with the increase in the degree of signal integration, the types of output signals on the motherboard increase. Since the transmission frequencies of different signals are different, if the motherboard connector is directly connected with a cable to transmit the signal output by the motherboard to the control circuit board, there may be large interference between the signals. Summary of the invention

[0004] The purpose of the present invention is to provide a signal transmission circuit, a design method and a server, which can reduce the generation of electromagnetic interference, effectively reduce the crosstalk between signals, and ensure the accurate transmission of signals.

[0005] In a first aspect, the present application provides a signal transmission circuit, which is applied to a server, wherein the server further comprises a mainboard and a mainboard connector, wherein a plurality of signal input terminals of the mainboard connector are respectively connected one-to-one with a plurality of signal output terminals of the mainboard, and the signal transmission circuit comprises:

[0006] The adapter board includes a plurality of input pins, at least one ground pin and a plurality of output pins, wherein the plurality of input pins are connected to the plurality of signal output ends of the mainboard connector in a one-to-one correspondence, and the plurality of output pins are connected to at least one control circuit board via cables;

[0007] The adapter board is provided with a plurality of signal routings, the input ends of the plurality of signal routings are respectively connected to a plurality of input pins and at least one ground pin in a one-to-one correspondence, and the output ends of the plurality of signal routings are respectively connected to a plurality of output pins in a one-to-one correspondence;

[0008] The arrangement of the signal wiring, the input pins and the ground pins on the adapter board is determined according to the signal parameters of the transmission signal itself, and the signal parameters include signal frequency and signal importance.

[0009] Optionally, the plurality of input pins include a first input pin and a second input pin, a signal frequency transmitted by the first input pin is greater than a preset value, and a signal frequency transmitted by the second input pin is not greater than the preset value;

[0010] The plurality of signal lines include a first signal line corresponding to the first input pin, a second signal line corresponding to the second input pin, and a ground line corresponding to the ground pin;

[0011] The plurality of input pins and the ground pins are divided into a plurality of first pin groups, each of the first pin groups includes at least one first input pin, at least one second input pin and / or at least one ground pin;

[0012] The plurality of signal routing lines are divided into a plurality of first routing groups, and each of the first routing groups includes at least one first signal routing line, at least one second signal routing line and / or at least one ground routing line.

[0013] Optionally, a ground pin is respectively provided on both sides of the first input pin, and at least one second input pin is correspondingly provided on the outer sides of the ground pin;

[0014] At least one ground wiring is disposed on both sides of the first signal wiring, and at least one second signal wiring is disposed on the outer sides of the ground wiring;

[0015] The outer side of the ground pin is a side away from the first input pin, and the outer side of the ground wiring is a side away from the first signal wiring.

[0016] Optionally, when the ground pins are arranged on both sides of all the first input pins, the number of ground pins required is greater than the number of ground pins actually provided on the adapter board;

[0017] At least one ground pin is respectively provided on both sides of the first input pin having a priority greater than the first priority;

[0018] At least one ground trace is disposed on both sides of a first signal trace having a priority greater than the first priority;

[0019] The priority of the first input pin and the priority of the first signal routing are determined according to the signal frequency and signal importance of the signals transmitted by themselves, and the priorities are positively correlated with the signal frequency and the signal importance, respectively.

[0020] Optionally, the first input pins whose priority is not greater than the first priority are divided into a second pin group according to signal type, and the first signal routing lines whose priority is not greater than the first priority are divided into at least one second routing group according to signal type;

[0021] The plurality of first input pins in each second pin group are adjacent to each other, and at least one of the ground pins and / or the second input pin is disposed on both sides of two outermost first input pins respectively;

[0022] The plurality of first signal routing lines in each second circuit group are adjacent to each other, and at least one of the ground routing lines and / or the second signal routing line is disposed on both sides of two outermost first signal routing lines.

[0023] Optionally, at least one first input pin is provided with two first signal routing lines, which are a first sub-signal routing line and a second sub-signal routing line;

[0024] There are at least two ground pins corresponding to two ground traces, which are a first sub-ground trace and a second sub-ground trace;

[0025] The first sub-ground routing lines respectively corresponding to the two ground pins are overlapped through a shielding layer, and the shielding layer is also overlapped with the first sub-signal routing line, and the shielding layer is grounded.

[0026] Optionally, the line width between any two of the signal routing lines is determined according to the signal frequency and / or signal importance of the signals transmitted by the two signal routing lines;

[0027] The line width is positively correlated with the signal frequency and the signal importance.

[0028] Optionally, the ground lines and / or the second signal lines between two adjacent second signal line groups are multiplexed with each other.

[0029] Optionally, a protection device is provided on the adapter board, and the protection device at least includes an electromagnetic interference suppression device and an electrostatic discharge protection device;

[0030] The electromagnetic interference suppression device is used to suppress electromagnetic wave interference, and the electrostatic discharge protection device is used to direct electrostatic discharge to the ground.

[0031] In a second aspect, the present application provides a server, comprising the signal transmission circuit as described above, and also comprising a mainboard and a mainboard connector, wherein the multiple signal input terminals of the mainboard connector are respectively connected one-to-one with the multiple signal output terminals of the mainboard, and the signal output terminals of the mainboard connector are respectively connected with the signal transmission circuit.

[0032] In a third aspect, the present application provides a design method for a signal transmission circuit, which is applied to the signal transmission circuit as described above, comprising:

[0033] Acquire a signal type of a mainboard output signal, and determine a signal frequency of the mainboard output signal according to the signal type;

[0034] Obtaining the signal importance level set by the user for a signal of a preset signal type;

[0035] Get the number of ground pins set on the adapter board;

[0036] The arrangement of the signal routing, input pins and ground pins on the adapter board is determined according to the number of the ground pins, the signal frequency of the mainboard output signal and the importance of the signal.

[0037] Optionally, the plurality of input pins include a first input pin and a second input pin, a signal frequency transmitted by the first input pin is greater than a preset value, and a signal frequency transmitted by the second input pin is not greater than the preset value;

[0038] After determining the signal frequency of the mainboard output signal according to the signal type, the method further includes:

[0039] Determine a first number of signals whose signal frequency is greater than a preset value, and a second number of signals whose signal frequency is not greater than the preset value;

[0040] After obtaining the number of ground pins set on the adapter board, it also includes:

[0041] According to the first number, the second number, and the number of the ground pins, determining whether the target number of the ground pins is greater than the number of ground pins provided on the adapter board, the target number being the number of ground pins required when the ground pins are provided on both sides of the first input pin;

[0042] If it is greater than, the priority of each signal is determined according to the signal frequency and signal importance of the mainboard output signal, and the priority is positively correlated with the signal frequency and the signal importance respectively;

[0043] The ground pin and / or the second input pin are allocated to each of the first input pins according to the priority, and the ground routing and the second signal routing are allocated to the first signal routing corresponding to each of the first input pins according to the priority.

[0044] The present application provides a signal transmission circuit, design method and server, which relates to the field of signal processing and solves the signal crosstalk and interference problems existing in current signal transmission. The signal transmission circuit introduces an adapter board, which includes multiple input pins, ground pins and output pins, and connects the input pins with the output pins through signal routing; in the adapter board, the arrangement of signal routing, input pins and ground pins is optimized according to the frequency and importance of the transmitted signal. At the same time, the newly added ground pins in the adapter board provide a return path for other signals, which can suppress electromagnetic radiation and reduce the risk of crosstalk and electromagnetic interference between signals. It can be seen that the signal transmission circuit in the present application can reduce the generation of electromagnetic interference, effectively reduce the crosstalk between signals, and ensure the accurate transmission of signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 It is a schematic diagram of differential mode radiation and common mode radiation;

[0047] Figure 2 A schematic diagram of a bus type and common frequencies provided by the present invention;

[0048] Figure 3 is a schematic diagram of a conventional signal transmission circuit;

[0049] Figure 4 A schematic diagram of a signal transmission circuit provided by the present invention;

[0050] Figure 5 A schematic diagram of a conventional pin arrangement;

[0051] Figure 6 A schematic diagram of the pin arrangement of an adapter board provided by the present invention;

[0052] Figure 7 A schematic diagram of the design of a shielding layer provided by the present invention;

[0053] Figure 8 A line width schematic diagram provided by the present invention;

[0054] Fig. 9 A schematic diagram of routing of an adapter board provided by the present invention;

[0055] Fig.10 The present invention provides a flow chart of a method for designing a signal transmission circuit. DETAILED DESCRIPTION

[0056] The core of the present invention is to provide a signal transmission circuit, design method and server, which can reduce the generation of electromagnetic interference, effectively reduce the crosstalk between signals, and ensure the accurate transmission of signals.

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Cable radiation is one of the most common problems. 90% of devices fail electromagnetic radiation tests due to cable radiation, some of which are power cables, but most of them are signal cables. Cables generate electromagnetic radiation such as Figure 1 As shown, one is the differential mode radiation generated by the signal current (differential mode current) loop in the cable, and the other is generated by the common mode current on the wires (including the shielding layer) in the cable.

[0059] The differential mode interference current flows between the signal line and the signal return line (or between the live wire and the neutral wire of the power line). In the signal cable, the differential mode interference current is induced by the external electromagnetic field in the loop formed by the signal line and the signal ground line. Because the signal line and its return line in the cable are very close, the loop area formed is very small, so the differential mode current induced by the external electromagnetic field is generally not very large. However, in the power line, the differential mode interference current is often emitted by the power supply of other electrical appliances on the power grid (especially the switching power supply) and generated when the inductive load is turned on and off, and its amplitude is often very large. The differential mode interference current will be superimposed on the useful signal and affect the normal operation of the equipment.

[0060] The calculation formula of differential mode radiation electric field is: E=263×10 -16 f 2 AI / r, where E is the electric field strength (V / m), f is the frequency of the current (MHz), A is the loop area of ​​the current (cm2), I is the current intensity (mA), and r is the distance from the test point to the current loop (m). It can be seen from the formula that the frequency of the current, the distance from the antenna to the circuit, and the current intensity in the circuit are all functional design indicators in the design process and generally cannot be changed. In order to reduce differential mode interference, the means we can take is to minimize the loop area of ​​the current. It can also be seen from the formula that the frequency of the signal is proportional to the size of the signal energy. Under the same conditions, when the signal frequency is low, the signal energy is also relatively low.

[0061] The common-mode interference current has the same amplitude / phase on all the conductors in the cable, and it flows in the loop formed between the cable and the earth (or the reference ground plane). There are three reasons for this interference current. One is that the external electromagnetic field induces a voltage on all the conductors in the cable (this voltage is of equal amplitude and phase relative to the earth), and this voltage generates a common-mode current; another reason is that the ground potentials of the devices at both ends of the cable are different, and current is generated under the drive of this ground voltage; the third reason is that there is a potential difference between the cable on the device and the earth, so there will be a common-mode current on the cable.

[0062] The calculation formula of common mode radiation electric field is: E=12.6×10 -7 fIL / r, where E is the electric field strength (V / m), f is the frequency of the current (MHz), L is the length of the cable (m), I is the current strength (mA), and r is the distance from the test point to the current loop (m).

[0063] From the formula, we can see that the frequency of the current, the distance from the antenna to the circuit, and the current intensity in the circuit are all functional design indicators in the design process and generally cannot be changed. In order to reduce common-mode interference, the means we can take is to minimize the cable length and ground the cable with as low impedance as possible. A commonly used method is the shielding design of the cable connector.

[0064] The essence of using shielded cables to control cable common-mode radiation is to reduce the loop area of ​​common-mode current. In the previous analysis, cables are the main radiation source because the common-mode current on the cables forms a large loop area, so a small common-mode current will lead to strong electromagnetic radiation. The purpose of adding electromagnetic shielding is to provide a path for the common-mode current to form a smaller loop area.

[0065] Since the function of the electromagnetic shielding layer is to provide a path for the common-mode current, thereby forming a smaller common-mode current loop area, the path formed by the shielding layer should have very low impedance, so that the common-mode current can easily return to GND from the shielding layer with the lowest impedance. The lower the impedance between the shielding layer and the metal chassis of the equipment, the shorter the common-mode current discharge path and the lower the electromagnetic radiation.

[0066] like Figure 2As shown in the figure, we can form examples of common bus types and corresponding signal names of servers. We can include the high-speed and low-speed bus types that can be encountered inside the server: I2C (Inter-Integrated Circuit), UART (Universal Asynchronous Receiver / Transmitter), JTAG, USB2.0 (Universal Serial Bus 2.0), I3C (Improved Inter-Integrated Circuit), SPI (Serial Peripheral Interface), ESPI (Enhanced Serial Peripheral Interface), SGPIO (Serial GPIO), NCSI (Network Controller Sideband Interface), MDI (1000-BaseT) (Medium Dependent Interface (1000-BaseT), RGMII (Reduced Gigabit Media Independent Interface, simplified Gigabit Media Independent Interface), SAS / SATA 3.0 (Serial Attached SCSI / Serial ATA 3.0), PCIe 3.0 (Peripheral Component Interconnect Express 3.0), from the above formula, we can see that the higher the signal rate, the stronger the signal energy that can be generated.

[0067] like Figure 3 The conventional signal transmission circuit is shown in FIG. 1 , in which the motherboard is provided with a motherboard connector according to the function, and the corresponding function on the motherboard is extended to the control circuit board. Figure 2 As shown, with the increasing number of server bus types and the increasing complexity of system functions, conventional design methods are difficult to meet design requirements.

[0068] First, as Figure 4As shown, the present application provides a signal transmission circuit, which is applied to a server. The server also includes a mainboard and a mainboard connector. Multiple signal input terminals of the mainboard connector are respectively connected one-to-one with multiple signal output terminals of the mainboard. The signal transmission circuit includes:

[0069] The adapter board includes a plurality of input pins, at least one ground pin and a plurality of output pins, wherein the plurality of input pins are connected to a plurality of signal output terminals of the mainboard connector in a one-to-one correspondence, and the plurality of output pins are connected to at least one control circuit board via cables;

[0070] The adapter board is provided with a plurality of signal traces, the input ends of the plurality of signal traces are respectively connected to a plurality of input pins and at least one ground pin in a one-to-one correspondence, and the output ends of the plurality of signal traces are respectively connected to a plurality of output pins in a one-to-one correspondence;

[0071] The arrangement of signal traces, input pins and ground pins on the adapter board is determined according to the signal parameters of the transmitted signal itself, and the signal parameters include signal frequency and signal importance.

[0072] The signal transmission circuit in the present application solves the signal crosstalk caused by signal frequency differences and electromagnetic interference problems in the current signal transmission process by introducing the design of an adapter board, and provides an optimized signal transmission method.

[0073] Specifically, the signal transmission circuit is used in the server and includes multiple input pins, ground pins and output pins. The input pins are connected one-to-one with the multiple signal output terminals of the motherboard connector, and the output pins are connected to the control circuit board through cables. The signal routing on the adapter effectively connects the input pins with the output pins to ensure the transmission of the signal. The ground pin plays a key role in the circuit. As a return path for the signal, it helps to effectively suppress electromagnetic radiation and reduce electromagnetic interference.

[0074] The arrangement of signal traces is optimized according to the frequency and importance of the signal. On the adapter board, the input pins and output pins are connected by signal traces, and the design of the signal traces should take into account the characteristics of the signal. For example, for high-frequency signals, the spacing between traces should be as large as possible to prevent interference between signals. At the same time, the reasonable layout of signal traces and ground pins can further improve the electromagnetic compatibility of the circuit and prevent high-frequency signals from interfering with low-frequency signals.

[0075] It should be understood that the setting and arrangement of the ground pins not only provide a return path for the signal, but also play a "shielding" role in the adapter board. The ground pin can effectively absorb and isolate the electromagnetic radiation generated by the signal to prevent these radiations from interfering with other signal lines or the external environment. By introducing at least one ground pin on the adapter board, the adapter board provides at least one return path for the output pins on the main board, which can reduce the crosstalk between signals to a certain extent. It can be understood that the more ground pins there are, the more corresponding signal return paths there are, and the less crosstalk is generated between the corresponding signals. The specific number of ground pins is determined according to the size of the adapter board and the needs of the user, and this application does not make specific restrictions here. In addition, the number of input pins and output pins is multiple, indicating that the number of input pins and the number of output pins are usually greater than or equal to three.

[0076] The frequency and importance of the signal play a decisive role in the design of the signal transmission circuit. Signals of different frequencies have different requirements for electromagnetic compatibility. High-frequency signals tend to generate stronger radiation, so their transmission paths need to be specially optimized, the routing should be kept short, and the layout of the ground pins should be fully considered for electromagnetic shielding; and for important signals (such as signals used for critical control), the stability and accuracy of their transmission must be prioritized. By analyzing the frequency and importance of the signal, the layout of the signal routing and the number of ground pins can be reasonably arranged to ensure that all signals can be transmitted smoothly with minimal interference.

[0077] In one embodiment, the adapter board includes an adapter connector, a PCB board and multiple sub-adapter boards, wherein the adapter connector is connected to the main board connector, the arrangement of multiple input pins and ground pins on the adapter connector is determined according to the signal parameters of the signal transmitted by itself, the arrangement of signal traces on the PCB board is determined according to the arrangement of multiple input pins and ground pins on the adapter connector and the signal parameters of the signal transmitted by itself, and the multiple sub-adapter boards are connected to a control circuit board one by one for signal classification and transmission to the corresponding control circuit board.

[0078] In this embodiment, the adapter board includes an adapter connector, a PCB board and a plurality of sub-adapters. The adapter connector is connected to the main board connector, and the signal is transmitted through a plurality of input pins and ground pins of the adapter connector. The arrangement of the input pins and the ground pins optimizes their performance based on the signal parameters of the transmission signal to ensure the integrity and anti-interference ability of the signal. For example, the input pins of high-frequency signals may need to be laid out through denser ground pins and lower impedance signal traces to reduce electromagnetic interference and signal crosstalk. The arrangement of the signal traces is also affected by the arrangement of the adapter connector and the signal frequency and importance of the transmission signal. The signal traces on the PCB board are reasonably laid out according to these parameters to ensure stable transmission of the signal and minimize mutual interference. In this system, a plurality of sub-adapters correspond to a control circuit board one by one, and the sub-adapters are responsible for classifying and transmitting the signals to the corresponding control circuit board. Each sub-adapter board provides a dedicated signal processing function for different signal types and application scenarios to ensure the correct transmission and processing of signals between different control circuit boards, thereby achieving efficient operation and stable operation of the entire system. Through this hierarchical design and signal distribution, the adapter board can be optimally configured according to the nature and requirements of the signal to improve the overall performance and reliability of the system.

[0079] The signal transmission circuit provided in this embodiment significantly reduces the crosstalk between signals through the optimized routing layout and ground pin setting, avoiding the influence caused by electromagnetic interference during signal transmission. In addition, the setting of the ground pin can effectively absorb and isolate radiation, further improving electromagnetic compatibility. By reducing the mutual interference between signals, the signal can be transmitted more stably and accurately, meeting the system's demand for high-precision signal transmission.

[0080] like Figure 5 As shown, Figure 5 In conventional pin design, there is generally no strict arrangement order for signals. The signals are just arranged on the connector. For example, the NCSI signal is to arrange and combine all the signals CLK, TXD0, TXD1, TXEN, RXD0, RXD1, TXEN, and CRSDV. Connecting the cables during routing will cause interference between the signals, resulting in problems with product functions and performance.

[0081] As an optional embodiment, the plurality of input pins include a first input pin and a second input pin, the frequency of a signal transmitted by the first input pin is greater than a preset value, and the frequency of a signal transmitted by the second input pin is not greater than the preset value;

[0082] The plurality of signal traces include a first signal trace corresponding to the first input pin, a second signal trace corresponding to the second input pin, and a ground trace corresponding to the ground pin;

[0083] The plurality of input pins and the ground pins are divided into a plurality of first pin groups, each of the first pin groups includes at least one first input pin, at least one second input pin and / or at least one ground pin;

[0084] The plurality of signal traces are divided into a plurality of first trace groups, each of which includes at least one first signal trace, at least one second signal trace and / or at least one ground trace.

[0085] In this embodiment, the input pins are differentiated according to the frequency of the transmitted signal. The frequency of the signal transmitted by the first input pin is greater than a preset value (usually a high-speed signal), while the frequency of the signal transmitted by the second input pin is not greater than the preset value (usually a low-speed signal). High-frequency signals are usually prone to strong electromagnetic radiation. If high-speed signals are placed together, crosstalk and signal quality degradation may occur.

[0086] The multiple signal traces include a first signal trace corresponding to a high-speed signal, a second signal trace corresponding to a low-speed signal, and a ground trace corresponding to a ground pin. The reasonable layout of the signal traces and the ground traces can effectively reduce the crosstalk and interference between the signals. For example, the high-speed signal trace and its corresponding ground trace are closely arranged together to form a shielding structure to reduce the propagation of radiated noise while also ensuring the stability of signal transmission.

[0087] The input pins and ground pins are divided into multiple first pin groups, each of which contains at least one first input pin, at least one second input pin and / or ground pin. The second signal pin can also serve as a return path for the first input pin to transmit the signal to a certain extent. Such division ensures the close integration of high-speed signals and ground pins, helps to optimize the electromagnetic shielding effect, and reduces mutual interference between signals. At the same time, the arrangement order of signal pins in each group helps to improve transmission efficiency and reduce unnecessary signal loss and delay.

[0088] Among them, when classified by frequency, low-speed signals (such as I2C, UART, VPP, etc.) usually have lower frequencies and are not susceptible to electromagnetic interference, but have lower requirements for electromagnetic compatibility; high-speed signals (such as I3C, SPI, PCIe, etc.) require higher signal transmission quality and require more stringent shielding design; the most important high-speed signals (such as PCIe 3.0 / 4.0 / 5.0, USB3.0, SATA, etc.) are critical to system performance and must adopt the best shielding strategy to avoid signal loss and interference.

[0089] As an optional embodiment, a ground pin is respectively provided on both sides of the first input pin, and at least one second input pin is correspondingly provided on the outer sides of the ground pin;

[0090] At least one ground trace is disposed on both sides of the first signal trace, and at least one second signal trace is disposed on the outer sides of the ground traces;

[0091] The outer side of the ground pin is a side away from the first input pin, and the outer side of the ground wiring is a side away from the first signal wiring.

[0092] In particular, a ground pin is provided on both sides of the first input pin, and at least one low-speed signal input pin is provided on the outer side of the ground pin. This layout helps to further shield the electromagnetic interference of the high-speed signal and ensure the stable transmission of the low-speed signal. Similarly, ground lines are provided on both sides of the first signal line, which enhances the shielding effect of the ground line on the signal and reduces the propagation of interference.

[0093] In order to reduce the crosstalk between different types of signals, high-speed signals and the most important signals are divided into dedicated areas to form a clear signal area layout. In particular, for the most important high-speed signals and clock signals, their transmission paths must be shielded by GND guard traces on both sides. The GND guard trace not only effectively absorbs the radiation of the signal, but also provides a stable return path to help the signal maintain stable transmission quality.

[0094] For the most important signals, such as clock signals and high-speed data lines, special emphasis is placed on setting GND protection lines on both sides of the signal lines, and GND return paths are also required on both sides of the clock signal. This design can effectively reduce the radiation generated by the clock signal and provide a stable reference ground for the clock signal, preventing the distortion or jitter of the clock signal from negatively affecting the system performance.

[0095] By rationally designing and planning the frequency and importance of the signal, we ensure that low-speed and high-speed signals will not interfere with each other. In the actual routing process, appropriate separation and shielding measures are adopted to ensure that each type of signal can be transmitted stably without interference. In particular, special design processing is carried out for the most important high-speed signals and clock signals to ensure the accuracy and stability of these key signals.

[0096] As an optional embodiment, when ground pins are arranged on both sides of all first input pins, the number of ground pins required is greater than the number of ground pins actually provided on the adapter board;

[0097] At least one ground pin is respectively provided on both sides of the first input pin having a priority greater than the first priority;

[0098] At least one ground trace is disposed on both sides of the first signal trace having a priority greater than the first priority;

[0099] The priority of the first input pin and the priority of the first signal routing are determined according to the signal frequency and signal importance of their own transmission signals, and the priority is positively correlated with the signal frequency and signal importance, respectively.

[0100] In signal transmission circuits, in order to ensure electromagnetic compatibility, especially for high-speed signals, the ground pin needs to be set close to the input signal pin to provide an effective return path and shielding effect. However, in some cases, the number of ground pins actually designed on the adapter board may not be enough to meet the requirement that ground pins need to be set on both sides of all first input pins. At this time, for input pins with a priority greater than the first priority (i.e., signals with higher frequency or greater importance), the design requires at least one ground pin to be set on both sides. In this way, signals with higher priority can obtain stronger electromagnetic shielding and noise suppression, reduce signal interference and distortion, and ensure transmission quality.

[0101] The priority of the first input pin and the priority of the signal routing are determined according to the frequency and importance of the signal. Generally speaking, the higher the frequency or the more important the signal, the higher its priority. This means that for high-frequency signals or signals that are critical to the system function (such as clock signals, high-speed data lines, etc.), the design will give priority to the optimization of their transmission paths to ensure that they are not interfered with by low-frequency or unimportant signals. For example, high-speed signals such as PCIe, USB 3.0, and SATA have a higher priority, and the design will ensure that there are sufficient ground pins and ground routing around them for electromagnetic shielding, so as to ensure that these critical signals can operate stably with the highest transmission quality. In the signal routing design, in addition to the ground pins around the input pins, ground routings are also required on both sides of the signal routing. For the first signal routing with a higher priority (such as the transmission line of a high-speed signal or an important signal), at least one ground routing should be configured on both sides, which can not only provide a stable return path for the signal, but also further reduce electromagnetic radiation and signal crosstalk. The function of the ground routing is to shield the radiation of the signal in the routing, and at the same time provide a stable reference ground to prevent the signal from being degraded due to external electromagnetic interference or internal crosstalk.

[0102] The priority setting in this embodiment is flexible, and the number and layout of ground pins and ground traces can be dynamically adjusted according to the characteristics of the signal (such as signal frequency and importance). For high-frequency or most important signals, more ground pins and ground traces are required on both sides to ensure sufficient shielding effect and stable signal transmission path. For low-frequency or less important signals, the number of ground pins and ground traces can be appropriately reduced to optimize the space utilization and cost of the adapter board.

[0103] As an optional embodiment, the first input pins with a priority not greater than the first priority are divided into a second pin group according to the signal type, and the first signal routing lines with a priority not greater than the first priority are divided into a plurality of second routing lines according to the signal type;

[0104] The multiple first input pins in each second pin group are adjacent to each other, and at least one ground pin and / or second input pin are respectively arranged on both sides of the two outermost first input pins;

[0105] The multiple first signal routing lines in each second circuit group are adjacent to each other, and at least one ground routing line and / or a second signal routing line are respectively arranged on both sides of the two outermost first signal routing lines.

[0106] In this embodiment, the first input pin and the first signal routing line whose priority is not greater than the first priority are divided into the second pin group and the second routing line group. By dividing the signal types, low-speed signals and signals of lower importance are classified into the second group. These signals have a lower transmission frequency or are less important to the system function, so they do not need to share the same space with high-frequency and important signals in the design. Through this grouping, the layout of the signal can be reasonably optimized within a limited design space.

[0107] The multiple first input pins in each second pin group are arranged adjacent to each other, and ground pins and / or second input pins are provided on both sides of the two outermost first input pins. The purpose of this design is to ensure that an effective shielding path is set between the pins. By setting ground pins or low-frequency signal pins on the periphery of the signal, electromagnetic interference and crosstalk between signals can be suppressed, providing an effective "shielding layer" to isolate high-frequency signals from low-frequency signals and secondary signals. Similarly, the multiple first signal traces in the second line group are also arranged in an adjacent layout, and ground traces and / or secondary signal traces are provided on both sides of the two outermost traces. Such a layout can not only reduce mutual interference between traces, but also further optimize the return path and electromagnetic compatibility of the signal, ensuring that the quality of the signal is not affected by external interference.

[0108] like Figure 6 As shown, in this embodiment, a ground line (GND) or a low-speed signal is used as an isolation barrier between high-speed signals to effectively reduce the interference of high-speed signals on other signals. For example, a layer of GND signal can be added to the outer layer of USB signals (such as USB_DP and USB_DN) to isolate them from the external environment and other signals; and an I2C signal (such as I2C3_SCL and I2C3_SDA) can be added to the outside for further isolation. This isolation can not only prevent the electromagnetic radiation of the USB signal from interfering with the I2C signal, but also avoid the interference of other signals on the USB signal, thereby ensuring the stability and transmission quality of the high-frequency signal.

[0109] In the design of SGPIO signals, ground lines are also designed on both sides of the clock signal SGPIO_SCLOCK, and low-speed signals (such as UART_TX, UART_RX, JTAG_TD1, JTAG_TD0, etc.) are further added on both sides of all signals. This design idea is to use the low-speed signal as an isolation barrier for high-speed signals, while ensuring that there is enough space and a stable current loop between signals to avoid interference between high-speed signals and other signals.

[0110] By rearranging the connector signals, it is ensured that there are ground signals on both sides of all high-speed clock signals, and the low-speed signals are placed between different signals for isolation, which greatly improves electromagnetic compatibility. High-speed clock signals have particularly strict requirements on electromagnetic compatibility, so it is necessary to ensure that there is sufficient ground protection on both sides to prevent electromagnetic wave radiation from affecting other signals. The role of low-speed signals is to prevent interference between high-frequency signals through physical isolation, ensuring the stable operation of the entire system.

[0111] like Figure 7 As shown, as an optional embodiment, at least one first input pin is provided with two first signal routing lines corresponding thereto, which are a first sub-signal routing line and a second sub-signal routing line;

[0112] There are at least two ground pins and two ground traces are arranged correspondingly, namely a first sub-ground trace and a second sub-ground trace;

[0113] The first sub-ground traces corresponding to the two ground pins are overlapped through the shielding layer, and the shielding layer is also overlapped with the first sub-signal trace, and the shielding layer is grounded.

[0114] In this embodiment, the use of a shielding layer is one of the key parts of the design, especially in the high-frequency part of signal transmission. Specifically, the first sub-ground traces corresponding to the two ground pins are overlapped by a shielding layer, the shielding layer is overlapped with the first sub-signal trace, and the shielding layer itself is grounded. The function of the shielding layer is to isolate signals with strong radiation to prevent them from radiating to the external environment and affecting other signals or surrounding circuits. The shielding layer is connected to the ground, which can effectively absorb and guide electromagnetic interference to the ground, thereby reducing the impact of radiation interference on the system and external devices.

[0115] For example, in order to enhance the return current path of the signal, ground wires (GND) are added to both ends of signals such as NCSI_CLK. This design not only provides a low-impedance return path for the signal, but also helps reduce the electromagnetic radiation that may be generated during the transmission of the signal. Especially for high-speed clock signals such as NCSI_CLK, the return path of the current is crucial, because any incomplete or unbalanced current loop will increase electromagnetic radiation and crosstalk.

[0116] Two GND cables (that is, two first sub-ground traces) are also designed inside the shielding layer. These ground traces are connected to the signal traces through low-impedance overlap to ensure that the signal return path is stable and efficient. In addition, the shielding layer can be made of materials such as aluminum foil or braided mesh, which further increases the shielding effect. The high conductivity of these materials helps to form a low-impedance connection between the shielding layer and the ground wire, allowing the shielding layer to more efficiently guide the interference current to the ground, thereby reducing the common-mode interference of the signal.

[0117] For example, similar shielding techniques are applied between NCSI signals such as NCSI_TXD0, NCSI_TXD1, NCSI_TXEN, NCSI_RXD0, NCSI_RXD1, NCSI_RXEN, NCSI_CRSDV. The shielding design between these signals reduces crosstalk between signals, especially crosstalk between high-speed signals, by ensuring that each signal minimizes radiation to the surrounding environment and other signals.

[0118] Configuring shielding layers on both sides of these signals and overlapping the shielding layers with low-impedance ground traces can effectively reduce the electromagnetic radiation of the signals and enhance the electromagnetic compatibility of the system.

[0119] As an optional embodiment, the line width between any two signal lines is determined according to the signal frequency and / or signal importance of the signals transmitted by the two signal lines;

[0120] The line width is positively correlated with the signal frequency and signal importance.

[0121] In this embodiment, the line width and spacing between signal traces are determined based on the signal frequency and importance to reduce interference (crosstalk) between signals. Signal frequency and importance are positively correlated with line width, that is, the higher the frequency and the more important the signal, the larger the trace width should be. This is because high-frequency signals and important signals are more sensitive to interference, and require more space and wider traces to ensure stable signal transmission. In addition, in order to further reduce crosstalk, the spacing between signal traces needs to be large enough, at least three times the line width.

[0122] like Figure 8 As shown in the figure, W represents the line width. According to experience, if the spacing is three times the line width, the crosstalk can be reduced by about 70%; if the spacing is increased to ten times the line width, the crosstalk can be reduced by up to 98%. This design method effectively reduces the electromagnetic interference between signals by reasonably controlling the signal routing width and spacing, ensuring the integrity of the signal and the electromagnetic compatibility of the system.

[0123] As an optional embodiment, the ground routing and / or second signal routing between two adjacent second signal routing groups are reused. In this embodiment, the wiring space on the PCB is reduced by reusing the ground routing and / or the second signal routing, and the electromagnetic compatibility of the signal is effectively improved. The same ground routing or signal routing is shared between adjacent second signal routing groups, which helps to optimize the layout and ensure good isolation between different signals. By sharing the ground routing or signal routing, the number of lines can be reduced, thereby reducing the wiring complexity and ensuring the stability of the signal return path. Such a design can reduce interference between signals and improve the overall performance of the system, especially in the design of dense signals and high frequencies, it can effectively reduce noise and crosstalk.

[0124] like Fig. 9 As shown, Fig. 9 In the figure, (1) is the GND via, (2) is the control circuit board, (3) is the protection device, (4) and (5) are the adapter boards connected to the control circuit board, (6) is the input pin and ground pin of the adapter board, and (6) is connected to the main board connector.

[0125] As an optional embodiment, a protective device is provided on the adapter board, and the protection period includes at least an electromagnetic interference suppression device and an electrostatic discharge protection device; wherein the electromagnetic interference suppression device is used to suppress electromagnetic wave interference, and the electrostatic discharge protection device is used to direct electrostatic discharge to the ground. In this embodiment, the anti-interference ability and stability of the system are enhanced by providing an electromagnetic interference suppression device and an electrostatic discharge protection device on the adapter board. The electromagnetic interference suppression device is used to suppress the interference of external electromagnetic waves on signal transmission, and ensure the integrity and accuracy of signal transmission. The electrostatic discharge protection device is used to direct the discharge caused by static electricity accumulation to the ground, so as to avoid static electricity from damaging sensitive circuits and components. These two protection devices work together to effectively improve the system's anti-electromagnetic interference and electrostatic discharge capabilities, and ensure the normal operation of the equipment in a complex electromagnetic environment.

[0126] In a second aspect, the present application provides a server, comprising a signal transmission circuit as described above, and also comprising a mainboard and a mainboard connector, wherein the multiple signal input terminals of the mainboard connector are respectively connected one-to-one with the multiple signal output terminals of the mainboard, and the signal output terminals of the mainboard connector are respectively connected with the signal transmission circuit.

[0127] For other introductions to the server, please refer to the above embodiments, and this application will not go into details here.

[0128] Thirdly, Fig.10 As shown, the present application provides a design method for a signal transmission circuit, which is applied to the above-mentioned signal transmission circuit, including:

[0129] S11: Acquire the signal type of the mainboard output signal, and determine the signal frequency of the mainboard output signal according to the signal type;

[0130] In this step, the different signal types (such as high-speed signals, low-speed signals, etc.) output by the motherboard are identified, and the corresponding signal frequency is determined according to the characteristics of each signal. The difference in signal frequency determines the signal transmission requirements and sensitivity to electromagnetic interference. High-speed signals usually require wider routing and better shielding measures to reduce signal crosstalk and interference. Therefore, determining the signal frequency is the key to the subsequent design of the signal transmission path.

[0131] S12: Obtaining the signal importance level set by the user for a signal of a preset signal type;

[0132] In this step, according to the system design requirements, the importance set by the user for different signal types (such as control signals, clock signals, data transmission signals, etc.) is obtained. The importance of a signal is directly related to its impact on the system function. Important signals (such as clock signals, data bus signals, etc.) require higher protection and isolation measures. Therefore, according to the importance of the signal, different design strategies can be decided on the adapter board, such as increasing the number of ground pins, optimizing the routing path, etc.

[0133] S13: Obtain the number of ground pins set on the adapter board;

[0134] In this step, the ground pin is used to provide a return path for the signal, effectively suppressing electromagnetic interference and signal crosstalk. By analyzing the number of existing ground pins, the position of the ground pin can be reasonably arranged during the design, and the signal routing and the ground pin can be well matched to provide sufficient shielding effect and reduce interference.

[0135] S14: Determine the arrangement of signal routing, input pins and ground pins on the adapter board according to the number of ground pins, the signal frequency of the mainboard output signal and the importance of the signal.

[0136] In this step, the layout of each signal on the adapter board is optimized based on the number of ground pins, signal frequency, and signal importance obtained earlier. When the signal frequency is high and the importance is high, the signal routing and ground pin positions need to be specially arranged to reduce crosstalk and provide effective shielding. For example, more ground pins are laid out around high-speed signals to enhance the signal return path and ensure signal integrity. For low-frequency and low-importance signals, fewer ground pins and a loose layout can be used. This optimization process helps ensure stable signal transmission and electromagnetic compatibility.

[0137] As an optional embodiment, the plurality of input pins include a first input pin and a second input pin, the frequency of a signal transmitted by the first input pin is greater than a preset value, and the frequency of a signal transmitted by the second input pin is not greater than the preset value;

[0138] After determining the signal frequency of the mainboard output signal according to the signal type, it also includes:

[0139] Determine a first number of signals having a signal frequency greater than a preset value, and a second number of signals having a signal frequency not greater than the preset value;

[0140] After obtaining the number of ground pins set on the adapter board, it also includes:

[0141] According to the first number, the second number, and the number of ground pins, it is determined whether the target number of ground pins is greater than the number of ground pins provided on the adapter board, the target number being the number of ground pins required when ground pins are provided on both sides of the first input pin;

[0142] If it is greater than, the priority of each signal is determined according to the signal frequency and signal importance of the mainboard output signal, and the priority is positively correlated with the signal frequency and signal importance respectively;

[0143] A ground pin and / or a second input pin is allocated to each first input pin according to the priority, and a ground trace and a second signal trace are allocated to the first signal trace corresponding to each first input pin according to the priority.

[0144] In this embodiment, based on the signal frequency, signal importance, and the number and layout requirements of the ground pins, the arrangement of the signal routing and ground pins on the adapter board is dynamically optimized to reduce interference between signals and ensure the transmission stability of high-frequency signals. First, different types of signals are distinguished by the size of the signal frequency. Signals with a signal frequency greater than a preset value (such as a high-speed signal) and signals with a signal frequency not greater than a preset value (such as a low-speed signal) are assigned to different input pins. Then, according to the frequency and importance of the signal, the priority of each signal is determined, and the signals are classified: high-speed signals and important signals are given priority to obtain more ground pins and more suitable routing paths to reduce crosstalk between signals and ensure signal integrity and accurate transmission.

[0145] If the number of ground pins on the adapter board is not enough to meet the needs of all signals (that is, the number of target ground pins is greater than the actual number of ground pins), the ground pins and traces are dynamically allocated according to the priority of the signal. For example, higher priority signals will be given priority to ground pins and shielding protection, and their corresponding signal traces will also be allocated to appropriate layout positions to avoid interference with low priority signals. In the layout of signal traces, high-frequency and important signal traces will be wrapped between ground pins and ground traces to enhance their electromagnetic compatibility and reduce crosstalk between signals.

[0146] In general, this optimized signal transmission circuit design can ensure that high-frequency and important signals receive sufficient electromagnetic shielding and ground pin support. At the same time, the layout of ground pins and signal traces is rationally planned to effectively improve signal transmission quality and the system's anti-interference capability.

[0147] For further introduction to the design method of the signal transmission circuit, please refer to the above embodiments, and this application will not go into details here.

[0148] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0149] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A signal transmission circuit, characterized in that: Applied to a server, the server further includes a mainboard and a mainboard connector, a plurality of signal input terminals of the mainboard connector are respectively connected one-to-one with a plurality of signal output terminals of the mainboard, and the signal transmission circuit includes: The adapter board includes a plurality of input pins, at least one ground pin and a plurality of output pins, wherein the plurality of input pins are connected to the plurality of signal output ends of the mainboard connector in a one-to-one correspondence, and the plurality of output pins are connected to at least one control circuit board through cables; The adapter board is provided with a plurality of signal routings, the input ends of the plurality of signal routings are respectively connected to a plurality of input pins and at least one ground pin in a one-to-one correspondence, and the output ends of the plurality of signal routings are respectively connected to a plurality of output pins in a one-to-one correspondence; The arrangement of the signal wiring, the input pins and the ground pins on the adapter board is determined according to the signal parameters of the transmission signal itself, and the signal parameters include signal frequency and signal importance.

2. The signal transmission circuit according to claim 1, characterized in that: The plurality of input pins include a first input pin and a second input pin, the frequency of a signal transmitted by the first input pin is greater than a preset value, and the frequency of a signal transmitted by the second input pin is not greater than the preset value; The plurality of signal lines include a first signal line corresponding to the first input pin, a second signal line corresponding to the second input pin, and a ground line corresponding to the ground pin; The plurality of input pins and the ground pins are divided into a plurality of first pin groups, each of the first pin groups includes at least one first input pin, at least one second input pin and / or at least one ground pin; The plurality of signal routing lines are divided into a plurality of first routing groups, and each of the first routing groups includes at least one first signal routing line, at least one second signal routing line and / or at least one ground routing line.

3. The signal transmission circuit according to claim 2, characterized in that: A ground pin is disposed on both sides of the first input pin, and at least one second input pin is correspondingly disposed on the outer sides of the ground pin; At least one ground wiring is disposed on both sides of the first signal wiring, and at least one second signal wiring is disposed on the outer sides of the ground wiring; The outer side of the ground pin is a side away from the first input pin, and the outer side of the ground wiring is a side away from the first signal wiring.

4. The signal transmission circuit according to claim 2, characterized in that: When the ground pins are arranged on both sides of all the first input pins, the number of ground pins required is greater than the number of ground pins actually provided on the adapter board; At least one ground pin is respectively provided on both sides of the first input pin having a priority greater than the first priority; At least one ground trace is disposed on both sides of a first signal trace having a priority greater than the first priority; The priority of the first input pin and the priority of the first signal routing are determined according to the signal frequency and signal importance of the signals transmitted by themselves, and the priorities are positively correlated with the signal frequency and the signal importance, respectively.

5. The signal transmission circuit according to claim 4, characterized in that: First input pins with a priority not greater than the first priority are divided into a second pin group according to signal type, and first signal traces with a priority not greater than the first priority are divided into at least one second trace group according to signal type; The plurality of first input pins in each second pin group are adjacent to each other, and at least one of the ground pins and / or the second input pin is disposed on both sides of two outermost first input pins respectively; The plurality of first signal routing lines in each second circuit group are adjacent to each other, and at least one of the ground routing lines and / or the second signal routing line is disposed on both sides of two outermost first signal routing lines.

6. The signal transmission circuit according to claim 5, characterized in that: There is at least one first input pin corresponding to two first signal routings, which are a first sub-signal routing and a second sub-signal routing; There are at least two ground pins corresponding to two ground traces, which are a first sub-ground trace and a second sub-ground trace; The first sub-ground routing lines respectively corresponding to the two ground pins are overlapped through a shielding layer, and the shielding layer is also overlapped with the first sub-signal routing line, and the shielding layer is grounded.

7. The signal transmission circuit according to claim 5, characterized in that: The ground lines and / or the second signal lines between two adjacent groups of the second signal lines are multiplexed with each other.

8. The signal transmission circuit according to claim 4, characterized in that: The line width between any two of the signal routing lines is determined according to the signal frequency and / or signal importance of the signals transmitted by the two signal routing lines; The line width is positively correlated with the signal frequency and the signal importance.

9. The signal transmission circuit according to any one of claims 1 to 8, characterized in that: The adapter board is provided with a protection device, and the protection device at least includes an electromagnetic interference suppression device and an electrostatic discharge protection device; The electromagnetic interference suppression device is used to suppress electromagnetic wave interference, and the electrostatic discharge protection device is used to direct electrostatic discharge to the ground.

10. A server, characterized in that: It includes the signal transmission circuit as described in any one of claims 1 to 9, and also includes a mainboard and a mainboard connector, wherein the multiple signal input terminals of the mainboard connector are respectively connected one-to-one with the multiple signal output terminals of the mainboard, and the signal output terminals of the mainboard connector are respectively connected with the signal transmission circuit.

11. A method for designing a signal transmission circuit, characterized in that: The signal transmission circuit according to any one of claims 1 to 9 comprises: Acquire a signal type of a mainboard output signal, and determine a signal frequency of the mainboard output signal according to the signal type; Obtaining the signal importance level set by the user for a signal of a preset signal type; Get the number of ground pins set on the adapter board; The arrangement of the signal routing, input pins and ground pins on the adapter board is determined according to the number of the ground pins, the signal frequency of the mainboard output signal and the importance of the signal.

12. The method for designing a signal transmission circuit according to claim 10, wherein: The plurality of input pins include a first input pin and a second input pin, the frequency of a signal transmitted by the first input pin is greater than a preset value, and the frequency of a signal transmitted by the second input pin is not greater than the preset value; After determining the signal frequency of the mainboard output signal according to the signal type, the method further includes: Determine a first number of signals whose signal frequency is greater than a preset value, and a second number of signals whose signal frequency is not greater than the preset value; After obtaining the number of ground pins set on the adapter board, it also includes: According to the first number, the second number, and the number of the ground pins, determining whether the target number of the ground pins is greater than the number of ground pins provided on the adapter board, the target number being the number of ground pins required when the ground pins are provided on both sides of the first input pin; If it is greater than, the priority of each signal is determined according to the signal frequency and signal importance of the mainboard output signal, and the priority is positively correlated with the signal frequency and the signal importance respectively; The ground pin and / or the second input pin are allocated to each of the first input pins according to the priority, and the ground routing and the second signal routing are allocated to the first signal routing corresponding to each of the first input pins according to the priority.

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