LED display control system and method

Abstract

The application provides an LED display control system and method, and relates to the technical field of LED display, and comprises the following steps: a daisy chain topology structure is formed by directly connecting a sending device and multiple receiving devices through a DP cable; an auxiliary signal interface circuit is arranged in the sending device and each receiving device; an AC coupling connection structure is adopted between the auxiliary signal interface circuit and an auxiliary channel differential line pair, and pull-up and pull-down resistors configured in a standard DP interface are removed; the system is configured to transmit auxiliary signals in the daisy chain topology structure by using the auxiliary channel differential line pair, and a Manchester coding mode is adopted when the auxiliary signals are transmitted, so that a transmission rate of greater than or equal to 100 Mbps can be supported. The technical scheme of the application achieves the effects of simplifying wiring and improving backhaul efficiency.

Description

Technical Field

[0001] This application relates to the field of LED display technology, specifically to an LED display control system and method. Background Technology

[0002] With the continuous advancement of technology, LED display technology has achieved remarkable development and has been widely used in numerous fields such as commercial advertising, stage performances, sporting events, and e-sports. In existing LED display control systems, the transmitting and receiving cards are typically cascaded using gigabit Ethernet cables or transmit video signals using standard DisplayPort interfaces. However, as display resolutions evolve towards 4K / 8K ultra-high definition, the bandwidth bottleneck of traditional gigabit Ethernet cables has become increasingly apparent. Often, at least dozens of Ethernet cables are needed for parallel transmission to meet high refresh rate requirements, resulting in extremely complex and costly system cabling. Furthermore, in large display systems composed of numerous cascaded receiving devices, real-time feedback of data such as the operating status, temperature, and calibration parameters of each device is crucial. However, existing solutions typically rely on additional, low-speed channels (such as standard DisplayPort AUX channels with a rate of only 1Mbps) or reverse network channels, independent of the video data link, to transmit this data. The former has an excessively low rate, making polling the entire system extremely time-consuming and unable to achieve effective monitoring; the latter further exacerbates cabling complexity and system costs. Therefore, there is an urgent need for an LED display control solution that can simplify wiring and significantly improve backhaul bandwidth and backhaul efficiency. Summary of the Invention

[0003] To address the aforementioned technical problems, this application provides an LED display control system and method.

[0004] In a first aspect, this application provides an LED display control system, including: a transmitting device and a multi-level receiving device; the transmitting device and the first-level receiving device, as well as two adjacent receiving devices, are directly connected via DP cables to form a daisy-chain topology; each DP cable includes a main link differential pair for transmitting display data and an auxiliary channel differential pair for transmitting auxiliary signals; each transmitting device and each receiving device is equipped with an auxiliary signal interface circuit, the auxiliary signal interface circuit and the auxiliary channel differential pair are connected by an AC coupling structure, and the pull-up and pull-down resistors configured in the standard DP interface are removed; the system is configured to use the auxiliary channel differential pairs to transmit auxiliary signals in the daisy-chain topology, and Manchester encoding is used when transmitting auxiliary signals to support a transmission rate greater than or equal to 100 megabits per second.

[0005] By adopting the above technical solution, the daisy-chain topology formed by direct connection of DP cables can simplify wiring and save costs; the main link differential pairs in the DP cable transmit display data, and the auxiliary channel differential pairs transmit auxiliary signals, realizing the separate transmission of display data and auxiliary signals; the auxiliary signal interface circuit adopts an AC coupling connection structure and removes pull-up and pull-down resistors, which can optimize signal transmission performance; the auxiliary channel differential pairs use Manchester encoding to transmit auxiliary signals, supporting a transmission rate of greater than or equal to 100 megabits per second, reducing display latency and significantly improving return bandwidth and return efficiency.

[0006] Optionally, each receiving device integrates dual DP interfaces, including a first DP interface and a second DP interface. The first DP interface is used to receive downlink display data transmitted by the transmitting device or the previous receiving device via a DP cable, and the second DP interface is used to forward downlink display data to the next receiving device. Alternatively, the second DP interface is used to receive auxiliary signals from the next receiving device transmitted via a DP cable, and the first DP interface is used to integrate the current level's return signal and the next receiving device's auxiliary signal before forwarding it to the previous receiving device. Finally, all auxiliary signals converge to the transmitting device.

[0007] By adopting the above technical solution, each receiving device integrates dual DP interfaces. The first DP interface receives downlink display data and can integrate return signals, while the second DP interface can forward downlink display data or receive auxiliary signals from the next level. This allows the display data to be transmitted smoothly in the daisy-chain topology, while the auxiliary signals can also be orderly converged to the transmitting device. This simplifies the wiring, solves the problem of complex wiring in traditional solutions, and can effectively transmit auxiliary signals, thus improving the return efficiency.

[0008] Optionally, the auxiliary signal interface circuit includes a differential signal driver and a differential signal receiver. Both the differential signal driver and the differential signal receiver are connected to the differential pairs of the auxiliary channel via AC coupling. The AC coupling architecture includes: DC blocking capacitors connected in series on the connection path between the output terminal of the differential signal driver and the DP cable, and on the connection path between the input terminal of the differential signal receiver and the DP cable; no resistors are connected to pull the signal level up to the power supply voltage or down to ground potential on the side of the DC blocking capacitor closest to the differential signal driver, or on the side of the DC blocking capacitor closest to the differential signal receiver. The auxiliary signal interface circuit also includes a first bias resistor and a second bias resistor, wherein the first differential output terminal of the differential signal driver is connected to the bias power supply terminal through the first bias resistor, and the second differential output terminal of the differential signal driver is connected to the bias power supply terminal through the second bias resistor; the first differential input terminal of the differential signal receiver is connected to the first differential output terminal of the differential signal driver, and the second differential input terminal of the differential signal receiver is connected to the second differential output terminal of the differential signal driver.

[0009] By adopting the above technical solution, the auxiliary signal interface circuit includes a differential signal driver and a differential signal receiver. The auxiliary signal interface circuit adopts an AC coupling connection structure that removes pull-up and pull-down resistors. The differential signal driver and the differential signal receiver are both AC coupled to the differential line pairs of the auxiliary channel. A DC blocking capacitor is connected in series and there are no pull-up or pull-down resistors on both sides of the DC blocking capacitor. A first and a second bias resistor are also set to connect the differential signal driver and the bias power supply terminal. The differential signal receiver is connected to the differential signal driver accordingly. This simplifies the wiring, greatly improves the backhaul bandwidth and backhaul efficiency, and avoids the problems of complex wiring and high cost caused by bandwidth bottlenecks in traditional solutions, as well as the problems of low speed channel rate and increased wiring complexity caused by reverse network channel.

[0010] Optionally, the receiving device has a built-in relay processing unit. The relay processing unit is configured to decode the encoded auxiliary signal received from the next-level receiving device through the auxiliary channel differential line, extract the return data of the next-level receiving device from the decoded signal, and integrate the return data of the current receiving device with the return data of the next-level receiving device, perform Manchester encoding, and then forward it to the next-level receiving device or transmitting device through the auxiliary signal interface circuit of the current receiving device.

[0011] By adopting the above technical solution, the receiving device has a built-in relay processing unit that can decode the encoded auxiliary signal from the next-level receiving device, extract the data returned by the next-level receiving device, integrate the data returned by the current level and the next level, encode it, and forward it to the next level or the transmitting device. This simplifies the wiring, improves the return bandwidth and return efficiency, and enables more efficient and accurate collection and transmission of return data from each level of receiving device.

[0012] Optionally, the return data transmitted via the auxiliary channel may include at least one of the following: operating status monitoring data of the receiving device, temperature data, brightness data, voltage of the power supply circuit, fault detection data of the LED display module, and coefficient data for color and brightness uniformity correction of the LED display.

[0013] By adopting the above technical solution, and utilizing auxiliary channel differential lines to transmit back data such as operating status monitoring data, temperature data, brightness data, power supply circuit voltage, LED display module fault detection data, and coefficient data for LED display color and brightness uniformity correction of the receiving devices in the daisy-chain topology, comprehensive monitoring and management of receiving devices at all levels can be achieved. This facilitates timely detection of equipment anomalies and allows for adjustments and corrections. Ultimately, this achieves the technical effect of real-time perception of the entire LED display system's status and long-term stable and reliable operation.

[0014] Optionally, the receiving device is electrically connected to the constant current source driver chip of the corresponding LED display module. After parsing and converting the received display data, the receiving device transmits the processed drive signal to the constant current source driver chip. The constant current source driver chip provides a constant operating current to the LED beads of the corresponding LED display module according to the drive signal, so as to realize the visual output of the display data.

[0015] By adopting the above technical solution, the receiving device is electrically connected to the constant current source driver chip of the LED display module. After parsing and format conversion of the display data, the driving signal is transmitted, so that the constant current source driver chip provides a constant working current to the LED beads, and the visualization output of the display data is realized.

[0016] Optionally, the transmitting device is configured to encapsulate display data and control information into a custom protocol message and send it to the receiving device via broadcast or multicast through the main link of the DP cable; the transmitting device is also configured to periodically insert a global synchronization feature code into the custom protocol message; each receiving device is used to extract the corresponding pixel data from the custom protocol message and perform dynamic frequency tracking calibration of the local reference clock according to the global synchronization feature code to generate a local display clock synchronized with the clock frequency of the transmitting device to drive the display scanning timing of the device at this level.

[0017] By adopting the above technical solution, the transmitting device can encapsulate display data and control information into custom protocol messages and broadcast or multicast them, which can efficiently transmit data to the receiving device. By periodically inserting global synchronization feature codes into the custom protocol messages, the receiving device can perform dynamic frequency tracking and calibration of its local reference clock, generate a local display clock synchronized with the clock frequency of the transmitting device, drive the display scanning timing of the local device, and realize the synchronous display of the display system.

[0018] Optionally, the transmitting device performs link delay measurement during the initialization phase: the transmitting device sends ranging sequences to each level of receiving devices and receives responses from each receiving device to calculate the physical transmission delay value from the transmitting device to each level of receiving device; the transmitting device sends the calculated delay compensation parameters corresponding to each receiving device to the corresponding receiving device; each receiving device performs alignment correction on the generated local vertical synchronization signal according to the corresponding delay compensation parameters, so that each level of receiving devices in the cascaded link maintains phase alignment during the display driving phase.

[0019] By adopting the above technical solution, the transmitting device performs link delay measurement, accurately calculates the physical transmission delay value to each level of receiving device, and sends the delay compensation parameters to the receiving device. Each receiving device aligns and corrects its local vertical synchronization signal according to the parameters, ensuring that each level of receiving device in the cascaded link maintains phase alignment during the display driving stage, thereby improving the display synchronization and stability of the LED display control system.

[0020] Optionally, custom protocol messages are sent using broadcast or multicast addresses; each receiving device has a unique physical location identifier pre-stored and is configured to filter and extract display data pointing to its own device from the broadcast or multicast custom protocol messages based on the physical location identifier.

[0021] By adopting the above technical solution, the receiving device can accurately filter out the display data load pointing to its own device from the custom protocol messages of broadcast or multicast, effectively avoiding data chaos and improving the accuracy and efficiency of data transmission.

[0022] Optionally, the receiving device also includes a video processing unit and a frame memory. The video processing unit is configured to receive and extract display data belonging to the receiving device at this level from the main link, perform image processing on the extracted display data and write the result into the frame memory, and read data from the frame memory under display timing control and send it to the constant current source driver chip corresponding to the receiving device at this level to drive the LED display module to display.

[0023] By adopting the above technical solution, the video processing unit of the receiving device can extract the display data of this level from the main link and perform image processing, store the results in the frame memory, and then read the data under the display timing control and send it to the constant current source driver chip to drive the corresponding LED display module to display, thus realizing effective processing and visualization output of display data.

[0024] Optionally, the transmitting device dynamically adjusts the display parameters based on the returned auxiliary signal. When the temperature of the target receiving device exceeds the safety threshold, it automatically reduces the driving current of the LED beads in the corresponding area of ​​the target receiving device or reduces the refresh rate to reduce heat generation. The system also supports remote cloud monitoring. The transmitting device packages and uploads the status information of all receiving devices it collects to the cloud server. Maintenance personnel can view the operating status of the LED display in real time through mobile terminals or web interfaces and issue remote calibration commands. After the remote calibration command reaches the transmitting device via the Internet, it is then sent to the target receiving device through the auxiliary channel differential line pair of the auxiliary channel.

[0025] By adopting the above technical solution, the display parameters can be dynamically adjusted according to the returned auxiliary signal. When the temperature of the target receiving device exceeds the safety threshold, the driving current or refresh rate of the LED beads in the corresponding area is reduced to reduce heat generation. It also supports remote cloud monitoring, and maintenance personnel can view the operating status of the display screen in real time and issue calibration commands. The calibration commands are issued by using the auxiliary channel differential line pair.

[0026] Optionally, both the transmitting and receiving devices include encoding and decoding logic units for implementing the Manchester encoding scheme. During encoding, the encoding and decoding logic unit transforms the original binary data stream into a signal waveform that does not contain a DC component and undergoes a level transition at the midpoint of each symbol period. During decoding, it recovers the original data 0 or 1 by detecting the level transition direction of the signal waveform at the midpoint of the symbol period, and extracts the self-synchronizing clock signal from the transition.

[0027] By adopting the above technical solution, the encoding and decoding logic unit transforms the original binary data stream into a signal waveform that does not contain DC components and is guaranteed to undergo a level transition at the middle of each symbol period during encoding, thus avoiding the influence of DC components on signal transmission. During decoding, the original data is recovered by detecting the direction of the level transition and extracted from the synchronization clock signal, which helps to ensure that the auxiliary signal is accurately transmitted in the daisy-chain topology at a rate of not less than 100 megabits per second.

[0028] In a second aspect of this application, an LED display control method is also provided, applied in the LED display control system of any of the preceding claims, comprising: directly connecting a transmitting device to a primary receiving device and adjacent receiving devices sequentially via DP cables to form a daisy-chain topology, wherein each DP cable includes a main link differential pair for transmitting display data and an auxiliary channel differential pair for transmitting auxiliary signals; configuring auxiliary signal interface circuits within the transmitting device and each receiving device such that the auxiliary signal interface circuits are connected to the auxiliary channel differential pairs using an AC coupling connection structure with pull-up and pull-down resistors removed; the transmitting device transmitting display data in the daisy-chain topology using the main link differential pairs in the DP cables, and the receiving device transmitting auxiliary signals in the daisy-chain topology using Manchester encoding using the auxiliary channel differential pairs in the DP cables.

[0029] In summary, one or more technical solutions provided in this application have at least the following technical effects or advantages: 1. Using DP cables to form a daisy-chain topology simplifies system wiring, reduces costs, and also reduces display latency; 2. Using auxiliary channel differential pairs in a daisy-chain topology, auxiliary signals are transmitted using Manchester encoding, supporting a transmission rate of 100 megabits per second or higher, which greatly improves the backhaul bandwidth and backhaul efficiency, and enables effective monitoring of auxiliary data such as the operating status of devices at all levels. Attached Figure Description

[0030] Figure 1 This is a framework diagram of an LED display control system provided in an embodiment of this application; Figure 2 This is a schematic diagram of the data flow of an LED display control system; Figure 3 This is a schematic diagram of a standard DP AUX circuit in related technologies; Figure 4 This is a schematic diagram of the DP AUX circuit provided in an embodiment of this application; Figure 5 This is a schematic diagram of the LED display control system architecture in related technologies; Figure 6 This is an overall architecture diagram of the LED display control system provided in the embodiments of this application; Figure 7 This is a schematic diagram of the connection between the sending card and the receiving card provided in an embodiment of this application; Figure 8 This is a flowchart of an LED display control method provided in an embodiment of this application. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0032] In the description of the embodiments of this application, the words "for example" or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design that is described as "for example" or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Rather, the use of the words "for example" or "for instance" is intended to present the relevant concepts in a specific manner.

[0033] In the description of the embodiments of this application, the term "multiple" means two or more. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0034] The LED display control system in related technologies has the following problems: (1) Bandwidth bottleneck: Traditional LED display control systems use gigabit network cables (1000Mbps) for interconnection. At ultra-large resolutions, the transmitting device needs to bring out a large number of network cables, resulting in extremely complex wiring. For example, to transmit a 4K resolution, taking 3840x2160@60HZ, 30bit color depth as an example, at least 16 network cables with a speed of 1Gbps are needed to transmit one frame of image in real time. As the display scale increases, the number of network cables input from the transmitting device to the display module increases exponentially, which will bring a huge workload to the wiring. The comparison between the number of different input channels and the corresponding number of cables is shown in Table 1.

[0035] Table 1 Data bandwidth required Custom DP transport protocol 1000Mbps Ethernet maximum effective bandwidth Number of DP cables required Minimum number of network cables required 4K video input (taking 3840x2160@60hz, 30bit as an example) 14.9Gbps 30.9Gbps 950Mbps 1 16 4K 3D video input (3840x2160@120hz, 30bit) 29.8Gbps 30.9Gbps 950Mbps 1 32 6-channel 4K video source input (non-3D) 89.4Gbps 30.9Gbps 950Mbps 6 96 6-channel 4K 3D video source input 178.8Gbps 30.9Gbps 950Mbps 6 192 (2) Significant delay: Traditional gigabit network transmission solutions are unable to support the real-time transmission of 4K ultra-high-definition signals. This bandwidth limitation directly leads to an increase in system end-to-end latency, resulting in noticeable lag in mouse compensation and joystick feedback in highly interactive application scenarios such as office operations or gaming, which seriously affects the real-time performance and consistency of user operations.

[0036] Figure 2 This is a data flow diagram of an LED display control system. Figure 2The table describes the data transmission process from the sending card to the receiving card, from the receiving card to the constant current source driver chip, and from the driver chip to the LED beads. Table 2 lists the latency information consumed at each stage when using gigabit network transmission. Table 3 shows the latency information of each stage of driving irregularly shaped screens, dome screens, etc., in a traditional LED display control system. Figure 2 An image correction device is added before the sending card. Table 4 shows the delay information for each stage of the scheme using the embodiments of this application.

[0037] Table 2 4K@60Hz video uses 16 gigabit Ethernet cables for transmission with varying latency levels. 1 frame = 1 / 60 second Sending Card 1 frame High-speed input video data is written into DDR memory, and after each frame is written, it is read out and sent to the receiving card via the network. Receiver card receives data 2 frames The receiving card receives data from the network, caches it in memory, reads the data out, remaps it to the arrangement required by the LED modules, and then writes it back to memory. Receiver card to constant current source chip 1 frame The receiving card reads the data to be displayed from memory and sends it to the constant current source chip. Constant current source chip drives LED beads 1 / 64 frame (latency is negligible) Minimum time for constant current source chip to drive LED beads one by one total 4+1 / 64 frames (approximately 66.9ms) Table 3 4K@60Hz video uses 16 gigabit Ethernet cables for transmission with varying latency levels. 1 frame = 1 / 60 second Traditional image correction equipment 2 frames This section is mainly used to correct the data in order to drive non-standard display modules such as irregularly shaped screens and dome screens. The latency varies among different companies, with traditional solutions typically having a latency of 2 frames. Sending Card 1 frame High-speed input video data is written into DDR memory, and after each frame is written, it is read out and sent to the receiving card via the network. Receiver card receives data 2 frames The receiving card receives data from the network, caches it in memory, reads the data out, remaps it to the arrangement required by the LED modules, and then writes it back to memory. Receiver card to constant current source chip 1 frame The receiving card reads the data to be displayed from the DDR memory and sends it to the constant current source chip. Constant current source chip drives LED beads 1 / 64 frame (latency is negligible) Minimum time for constant current source chip to drive LED beads one by one total 6+1 / 64 frames (approximately 100.3ms) Table 4 4K@60Hz video uses a single DP cable to transmit data with varying delay levels. 1 frame = 1 / 60 second Sending Card 0 frames High-speed input video data is transmitted directly to the receiver card via the DP cable, without the need for storage. Receiver card receives data 1 frame The receiving card processes the received data, adjusts it to the layout required by the LED modules, and then caches it in the DDR. This processing includes correction for irregularly shaped screens, spherical screens, cylindrical screens, etc.; for flat screens, this process can be ignored. Receiver card to constant current source chip 1 frame The receiving card reads the data to be displayed from the DDR memory and sends it to the constant current source chip. Constant current source chip drives LED beads 1 / 64 frame (latency is negligible) Minimum time for constant current source chip to drive LED beads one by one total 2+1 / 64 frames (approximately 33.6ms) (3) Low return efficiency: The AUX bus in the standard DP protocol only supports a rate of 1Mbps. In systems with dozens or even hundreds of receiver cards cascaded, the return speed of monitoring data and correction parameters is extremely slow.

[0038] (4) System redundancy: If additional network cables are added for high-speed backhaul, the cost of cables, interface size and PCB materials will increase significantly, and the complexity of wiring will also increase.

[0039] To address the aforementioned problems in related technologies, this application provides an LED display control system. Figure 1 This is a framework diagram of an LED display control system provided in an embodiment of this application. The system includes: a transmitting device and a multi-level receiving device; the transmitting device and the first-level receiving device, as well as two adjacent receiving devices, are directly connected via DP cables to form a daisy-chain topology; each DP cable includes a main link differential pair for transmitting display data and an auxiliary channel differential pair for transmitting auxiliary signals; each transmitting device and each receiving device is equipped with an auxiliary signal interface circuit, and the auxiliary signal interface circuit and the auxiliary channel differential pair adopt an AC coupling connection structure, and the pull-up and pull-down resistors configured in the standard DP interface are removed; the system is configured to use the auxiliary channel differential pairs to transmit auxiliary signals in the daisy-chain topology, and Manchester encoding is used when transmitting auxiliary signals to support a transmission rate greater than or equal to 100 megabits per second.

[0040] In this embodiment, using DP cables to form a daisy-chain topology simplifies wiring and saves costs. The main link differential pairs in the DP cable transmit display data, while the auxiliary channel differential pairs transmit auxiliary signals, achieving separate transmission of display data and auxiliary signals. The auxiliary signal interface circuit adopts an AC coupling connection structure and removes pull-up and pull-down resistors, which optimizes signal transmission performance. The auxiliary channel differential pairs use Manchester encoding to transmit auxiliary signals, supporting a transmission rate of 100 megabits per second or higher, reducing display latency and significantly improving return bandwidth and return efficiency.

[0041] This embodiment applies the DP physical link and its native architecture to the interconnection of internal devices in an LED control system, and deeply customizes the standard DP auxiliary (AUX) channel for this specific application scenario. Specifically, the system in this embodiment abandons the traditional Ethernet-based "star" or "tree" network topology, and constructs a daisy-chain serial cascade structure through DP cables. This structure utilizes the native bandwidth of the DP main link (MainLink) of up to tens of Gbps to carry all downlink display data with a single cable. This solves the fundamental problem of extremely complex wiring and crowded interfaces for large-scale, ultra-high resolution LED screens from the physical connection level. At the same time, the auxiliary signal interface circuit of the transceiver equipment is modified in hardware, adopting an AC coupling structure and removing the pull-up and pull-down resistors of the standard DP interface to form an optimized AC coupling structure, which improves signal integrity and transmission distance, eliminates impedance interference and signal reflection, and, with Manchester encoding, achieves DC balance and self-synchronization transmission of the auxiliary signal, supporting auxiliary channel rates of 100Mbps and above. This solution addresses the issues of complex gigabit network cabling and insufficient bandwidth in LED display systems, as well as the limitations of standard DP auxiliary channels with a return rate of only 1Mbps, which cannot meet the requirements of large-scale cascaded real-time monitoring. It also avoids the increased cost and complexity associated with additional return lines. Ultimately, it achieves the technical benefits of replacing multiple network cables with a single DP cable, high-speed auxiliary signal return, simplified system cabling, lower latency, and enhanced stability, making it suitable for ultra-high-definition and large-scale cascaded LED display scenarios. Through this embodiment, replacing a massive number of network cables with a single or a few DP cables greatly simplifies physical connections and reduces material, construction, and maintenance costs. The modified AUX channel can provide a return bandwidth of over 100Mbps, enabling millisecond-level status polling or parameter distribution to hundreds of receiving cards in large-scale systems, achieving unprecedented real-time monitoring and control capabilities. Furthermore, due to the high bandwidth of the DP main link and the daisy-chain topology, display data does not require large-capacity frame buffering at the sending end, enabling "instant transmission," significantly improving display real-time performance and meeting the needs of highly interactive scenarios such as gaming, VR, and esports live streaming.

[0042] Suppose an esports arena needs to install a spherical LED display screen with a diameter of 5 meters to broadcast live match footage. Resolution requirements: 7680×4320 (8K) resolution, 120Hz refresh rate, 30-bit color depth.

[0043] The pain points of related technologies: If traditional solutions are used, the theoretical bandwidth requirements are extremely high, which may require more than 60 gigabit network cables to be run from the transmitting box to the various receiving cards inside the spherical screen. The wiring is almost impossible to complete within the limited spherical support, and there will be a significant delay in the player's operation feedback.

[0044] The implementation process of this embodiment is as follows: Connection deployment: Engineers only need to run a DP cable from the transmit card in the control room to the first receive card on top of the spherical screen.

[0045] Cascading transmission: Receiver card #1 is connected to receiver card #2 via another short DP cable, and so on, up to receiver card #N covering the entire sphere. All video data is transmitted downlink at high speed via the DP main link.

[0046] Real-time display: The 8K@120Hz video stream is transmitted via a single DP cable, eliminating the need for extensive buffering on the transmitting card; it transmits directly. Upon receiving the data, the receiving card performs spherical distortion correction (buffering 1 frame) and then drives the LED beads. The overall latency is controlled to approximately 2 frames, ensuring near-synchronous operation between the player and the screen display.

[0047] Status monitoring: The temperature, voltage, and operating status data of each receiving card inside the spherical screen are transmitted back to the transmitting card in Manchester encoding, step by step, from the Nth card through the modified high-speed AUX channel (100Mbps). Administrators can monitor the status of hundreds of nodes in real time without laying any additional backhaul cables.

[0048] In one optional embodiment, each receiving device integrates dual DP interfaces, including a first DP interface and a second DP interface. The first DP interface is used to receive downlink display data transmitted by the transmitting device or the previous receiving device via a DP cable, and the second DP interface is used to forward the downlink display data to the next receiving device. Alternatively, the second DP interface is used to receive auxiliary signals from the next receiving device transmitted via a DP cable, and the first DP interface is used to integrate the current level's return signal and the next level's auxiliary signal before forwarding them to the previous receiving device. Finally, all auxiliary signals converge to the transmitting device.

[0049] In this embodiment, each receiving device integrates dual DP interfaces. The first DP interface receives downlink display data and can integrate backhaul signals, while the second DP interface can forward downlink display data or receive auxiliary signals from the next level. This allows display data to be transmitted smoothly in the daisy-chain topology, while auxiliary signals can also be orderly converged to the transmitting device. This simplifies wiring, solves the problem of complex wiring in traditional solutions, and effectively transmits auxiliary signals, thus improving backhaul efficiency.

[0050] By configuring a first DP interface and a second DP interface for each receiving device, a bidirectional switchable transmission path is formed. In the downlink direction, the main link differential pair receives data from the previous level through the first DP interface and transparently forwards it to the next level via the second DP interface, ensuring the continuity of the video stream. In the uplink direction, the auxiliary channel differential pair uses the second DP interface to receive the auxiliary signal returned from the lower level. After integrating it with the signal of this level, it is converged upwards through the first DP interface. That is, downlink transparent transmission of display data and uplink convergence of auxiliary signals are completed within the same daisy-chain topology. This embodiment solves the problems of traditional LED cascading systems requiring independent transmit and receive interfaces, redundant wiring, chaotic data forwarding logic, and inability to converge back signals level by level. At the same time, it avoids topology rigidity caused by fixed interface functions. Ultimately, it achieves the technical effects of a single DP link simultaneously completing downlink distribution and uplink return, interface adaptability according to transmission direction, non-blocking data during large-scale cascading, and auxiliary signals being relayed up level by level and finally converged to the transmitting device, greatly improving the system's scalability and reliability.

[0051] Taking the cascading of three receiver cards (i.e., receiving devices) in a daisy-chain topology as an example, assuming card A is the first stage, card B is the middle stage, and card C is the last stage, card A is also connected to the transmitting device. Card A has DP_IN_A (first DP interface) connected to the transmitting device and DP_OUT_A (second DP interface) connected to card B; card B has DP_IN_B (first DP interface) connected to card A and DP_OUT_B (second DP interface) connected to card C; card C only has DP_IN_C connected to card B, and its DP_OUT_C ​​can be left unused or connected to a terminating resistor. Downlink video transmission process (from the transmitting device to the LED screen): The transmitting device sends 4K video data to the first DP interface of card A via a DP cable. Card A, through its internal circuitry, transparently forwards the video data to the first DP interface of card B via its second DP interface; card B also forwards the data to card C via its second DP interface. Uplink auxiliary signal feedback (convergence process): Card C (end-stage) collects its own temperature data. Since Card C is the final stage, it directly sends the temperature data to Card B's second DP interface through its first DP interface (which serves as the uplink channel at this time). After receiving the data from Card C, Card B temporarily stores it. At the same time, Card B collects its own voltage data. Card B's controller integrates the "temperature data from Card C" and the "voltage data from Card B" into a data packet. Then, Card B sends the integrated data packet to Card A's second DP interface through its first DP interface. After receiving the integrated data packet from Card B, Card A adds its own brightness correction coefficient and finally sends all the data from all three levels of devices back to the transmitting device through its first DP interface.

[0052] In an optional embodiment, the auxiliary signal interface circuit includes a differential signal driver and a differential signal receiver, both of which are AC-coupled to the differential pairs of the auxiliary channel. The AC coupling architecture includes: DC blocking capacitors connected in series on the connection path between the output of the differential signal driver and the DP cable, and on the connection path between the input of the differential signal receiver and the DP cable; no resistors are connected to pull the signal level up to the power supply voltage or down to ground potential on the side of the DC blocking capacitor closest to the differential signal driver and the side of the DC blocking capacitor closest to the differential signal receiver. The auxiliary signal interface circuit also includes a first bias resistor and a second bias resistor, wherein the first differential output of the differential signal driver is connected to the bias power supply terminal through the first bias resistor, and the second differential output of the differential signal driver is connected to the bias power supply terminal through the second bias resistor; the first differential input of the differential signal receiver is connected to the first differential output of the differential signal driver, and the second differential input of the differential signal receiver is connected to the second differential output of the differential signal driver.

[0053] In this embodiment, the auxiliary signal interface circuit includes a differential signal driver and a differential signal receiver. The auxiliary signal interface circuit adopts an AC coupling connection structure that removes pull-up and pull-down resistors. Both the differential signal driver and the differential signal receiver are AC coupled to the differential line pairs of the auxiliary channel. A DC blocking capacitor is connected in series, and there are no pull-up or pull-down resistors on both sides of the DC blocking capacitor. A first and a second bias resistor are also provided to connect the differential signal driver and the bias power supply terminal. The differential signal receiver is connected to the differential signal driver accordingly. This simplifies the wiring, greatly improves the backhaul bandwidth and backhaul efficiency, and avoids the problems of complex wiring and high cost caused by bandwidth bottlenecks in traditional solutions, as well as the problems of low speed channel rate and increased wiring complexity caused by reverse network channel.

[0054] The standard DP AUX channel employs an AC coupling structure including pull-up and pull-down resistors. These resistors are used to stabilize the line potential to a defined level (e.g., pull-up to power, pull-down to ground) when there is no signal transmission, ensuring that the receiver can clearly identify the logic state. However, when driving long cables or cascading multiple stages, these resistors interact with the cable's distributed capacitance and termination impedance, degrading signal edges, increasing reflections, and limiting available bandwidth. This is one of the fundamental physical reasons why its rate is limited to 1 Mbps. This embodiment refactors the auxiliary signal interface circuit in hardware, using a differential signal driver and a differential signal receiver as the core transceiver unit. It utilizes DC blocking capacitors to achieve AC coupling, completely removing the pull-up and pull-down resistors in the standard DP interface that cause impedance mismatch and signal reflections. At the same time, it adds first and second bias resistors to provide a stable bias voltage for the differential output, enabling the circuit to maintain a normal differential signal level even without pull-up and pull-down resistors. This embodiment introduces a novel DC biasing scheme: by using a first bias resistor and a second bias resistor, the two differential outputs of the differential driver are directly biased to a specific bias power supply voltage (e.g., a 1.2V common-mode voltage). Due to the presence of the AC coupling capacitor, this bias voltage is not transmitted to the cable, but instead provides a stable and symmetrical DC operating point only for the interface circuit on the driver side. The receiver-side circuit structure is mirror-symmetrical; its input receives AC signals through a capacitor, while its own DC bias is provided by its internal circuitry or a similar bias network. This embodiment aims to solve the technical problems of standard DP auxiliary channel circuits, such as severe signal attenuation and reflection during high-speed transmission due to pull-up and pull-down resistors, which prevent them from supporting 100Mbps high-speed transmission. It also avoids the risks of DC level misalignment and interface damage. Ultimately, it enables the auxiliary channel to possess high-speed, low-interference, long-distance, and highly stable transmission capabilities, providing reliable hardware support for 100Mbps backhaul and adapting to the high-speed auxiliary signal transmission requirements of large-scale LED cascade systems. Through this embodiment, the AUX channel, originally used only for low-speed control, acquires high-speed data transmission capabilities, meeting the needs of real-time monitoring and large-volume data transmission.

[0055] In an optional embodiment, the receiving device has a built-in relay processing unit configured to decode the encoded auxiliary signal received from the next-level receiving device via the auxiliary channel differential line, extract the return data from the next-level receiving device from the decoded signal, integrate the return data from the current receiving device with the return data from the next-level receiving device, perform Manchester encoding, and then forward it to the next-level receiving device or transmitting device through the auxiliary signal interface circuit of the current receiving device.

[0056] In this embodiment, the receiving device has a built-in relay processing unit that can decode the encoded auxiliary signal from the next-level receiving device, extract the data returned by the next-level receiving device, integrate the data returned by the current level and the next level, encode it, and forward it to the next level or the transmitting device. This simplifies wiring, improves the return bandwidth and return efficiency, and enables more efficient and accurate collection and transmission of return data from each level of receiving device.

[0057] In this embodiment, each receiving device has a built-in relay processing unit. It first decodes the Manchester-encoded auxiliary signal uploaded by the lower-level device (such as the lower-level receiving card), extracts the data returned from the lower level, merges it with the data returned from the current level, then re-encodes it in Manchester and forwards it upwards, forming a relay-style return mechanism of decoding-extraction-merging-encoding-uploading. This solves the problems in traditional LED cascading systems, such as the inability of auxiliary signals to be relayed step-by-step, the potential for congestion and conflict caused by simultaneous return from a large number of receiving devices, the inability of standard DP low-speed channels to handle multi-level converged data, and excessive return delays and data loss. The relay processing unit achieves node-by-node shaping, regeneration, and convergence of the auxiliary signal, ensuring stable and reliable signal transmission over long distances in multi-level daisy-chain transmissions. Ultimately, it achieves the technical effect of high-speed convergence, non-blocking, distortion-free, and real-time return of auxiliary signals under large-scale cascading, supporting status monitoring and parameter correction for hundreds of receiving devices. The relay processing unit acts as a relay station, relaying and processing the transmitted auxiliary signal to ensure the quality and integrity of the signal during transmission. It can amplify and shape signals, overcoming signal attenuation and distortion during transmission, ensuring that auxiliary signals are accurately delivered to the next-level device. In traditional master-slave polling mode, the sending device must sequentially query multiple receiving devices (e.g., 100 receiving cards), resulting in huge communication overhead and long processing times (potentially several seconds or even longer), making real-time monitoring impossible. In this embodiment, the sending device only needs to receive a single data frame containing information from all nodes, greatly simplifying the sending end's processing logic. The overall system status update time depends only on the sum of the longest link's transmission delay and the processing delay of each node, representing an order-of-magnitude improvement compared to polling mode. Since each node only communicates with its direct upstream and downstream neighbors, adding or removing devices at the end of the link has no impact on the logic of the preceding nodes. This allows the system to easily scale to hundreds or even thousands of receiving devices without causing protocol failure or performance bottlenecks. Because the data return speed is extremely fast (e.g., the entire link's data can be refreshed within tens of milliseconds), the sending device can respond quickly based on the latest and most comprehensive status data. For example, once an abnormal temperature of a receiving card is detected, the brightness of the corresponding area can be adjusted immediately in the next frame of video data to reduce power consumption and heat generation, forming a fast closed-loop control, which is something that traditional slow backhaul solutions cannot achieve.

[0058] In an optional embodiment, the return data transmitted via the auxiliary channel includes at least one of the following: operating status monitoring data of the receiving device, temperature data, brightness data, voltage of the power supply circuit, fault detection data of the LED display module, and coefficient data for LED display color and brightness uniformity correction.

[0059] In this embodiment, auxiliary channel differential lines are used to transmit back data such as operating status monitoring data, temperature data, brightness data, power supply circuit voltage, LED display module fault detection data, and coefficient data for LED display color and brightness uniformity correction of the receiving devices in the daisy-chain topology. This enables comprehensive monitoring and management of receiving devices at all levels, facilitating timely detection of equipment anomalies and subsequent adjustments and corrections. Ultimately, this achieves the technical effect of real-time perception of the entire LED display system's status and long-term stable and reliable operation.

[0060] Key maintenance and calibration data, such as the receiving device's operating status, temperature, brightness, power supply voltage, fault detection information, and color brightness uniformity correction coefficient, are included in the high-speed backhaul range. This backhaul data is crucial for real-time monitoring of the system's operating status and ensuring display quality. For example, operating status monitoring data allows staff to understand whether the receiving device is working properly and whether there are any abnormalities; temperature data helps determine the device's heat dissipation; excessively high temperatures may affect the device's performance and lifespan, requiring timely cooling measures; fault detection data can promptly identify faults in the LED display module for rapid repair and replacement. Combined with the constructed 100Mbps high-speed auxiliary channel and relay cascading aggregation mechanism, unified carrying and real-time uploading of various system-critical data are achieved. This embodiment addresses the technical problems of traditional low-speed auxiliary channels, which suffer from insufficient bandwidth, making it impossible to simultaneously transmit massive amounts of multi-type monitoring and correction data. Furthermore, the reliance on single-polling methods leads to system maintenance delays, low correction efficiency, and the inability to provide real-time fault warnings. The solution enables the transmitting device to comprehensively monitor the entire operational status of the entire LED display system. The transmitting device is no longer merely a video signal source but transforms into an intelligent monitoring center, capable of real-time monitoring of the display's "health status" and implementing preventative maintenance. Ultimately, it achieves the technical effects of real-time perception of the entire LED display system's status, online fine-grained correction, rapid fault location, and long-term stable and reliable operation, significantly improving the intelligent operation and maintenance level and display effect of large-scale LED display systems.

[0061] Auxiliary signals can be bidirectional transmission signals, such as monitoring data uploaded from the receiving device to the transmitting device, or control commands or update data sent from the transmitting device to the receiving device. The monitoring data may include the operating status parameters of each receiving device, and the control commands or update data may be data packets for firmware upgrades or calibration parameters for adjusting the LED display module.

[0062] In an optional embodiment, the receiving device is electrically connected to the constant current source driver chip of the corresponding LED display module. After parsing and converting the received display data, the receiving device transmits the processed drive signal to the constant current source driver chip. The constant current source driver chip provides a constant operating current to the LED beads of the corresponding LED display module according to the drive signal, thereby realizing the visual output of the display data.

[0063] In this embodiment, the receiving device is electrically connected to the constant current source driver chip of the LED display module. After parsing and format conversion of the display data, it transmits the drive signal, enabling the constant current source driver chip to provide a constant operating current to the LED beads, thus achieving the visual output of the display data. The receiving device parses and converts the ultra-high-definition display data transmitted via the main link, generating a drive signal adapted to the LED driving timing. The constant current source driver chip then provides a constant current to the LED beads, completing the visual output of the display data. Through the coordinated operation of the receiving device and the constant current driver chip, complete link control from digital signal to optical output of the display data is achieved, ultimately achieving the technical effects of stable, flicker-free display, high brightness uniformity, extended LED bead lifespan, and strong system drive compatibility, ensuring high-quality output of the ultra-high-definition large-scale LED display system.

[0064] In an optional embodiment, the transmitting device is configured to encapsulate display data and control information into a custom protocol message and send it to the receiving device via broadcast or multicast through the main link of the DP cable; the transmitting device is also configured to periodically insert a global synchronization feature code into the custom protocol message; each receiving device is used to extract the corresponding pixel data from the custom protocol message and perform dynamic frequency tracking calibration of the local reference clock according to the global synchronization feature code to generate a local display clock synchronized with the clock frequency of the transmitting device to drive the display scanning timing of the device at this level.

[0065] In this embodiment, the transmitting device encapsulates display data and control information into a custom protocol message and broadcasts or multicasts it, efficiently transmitting data to the receiving device. Periodically inserting a global synchronization feature code into the custom protocol message allows the receiving device to dynamically track and calibrate its local reference clock, generating a local display clock synchronized with the transmitting device's clock frequency. This drives the display scanning sequence of the local device, achieving synchronized display of the entire display system. This embodiment aims to construct a lightweight and intelligent communication and synchronization protocol for LED display cascade systems. Its principle is to abandon the complex video stream encapsulation of the standard DP protocol and define a highly customized "custom protocol message" that encapsulates the core elements of the display system (including pixel data, control commands, and global synchronization markers) in a single data stream, enabling efficient transmission via the DP main link. The transmitting device acts as the "master director," packaging the raw image data to be displayed along with various control commands (such as brightness adjustment and correction parameter updates) into a custom-formatted data packet (message). Crucially, it periodically inserts a special "global synchronization signature" into this data stream. This signature serves as the absolute time reference point for all receiving devices to work collaboratively. The transmitting device injects this composite data stream into the daisy chain via "broadcast" or "multicast," meaning all receiving devices can "hear" the complete data stream. Each receiving device acts as a "local executor." It first filters and extracts the portion of "pixel data" pre-assigned to its driving area from the broadcast stream. More importantly, it needs to accurately capture the periodically appearing "global synchronization signature" in the data stream. Once this signature is captured, the receiving device's internal clock management circuitry (such as a digital phase-locked loop, DPLL) uses it as a reference to dynamically reconstruct (or phase-lock) a "local display clock" whose frequency is strictly synchronized with the transmitting end's master clock. This local clock will be used directly to control the precise timing of pixel scanning and PWM grayscale modulation of the LED module at this level, thereby ensuring that the scanning progress of hundreds or thousands of screen areas driven by receiver cards on the link remains synchronized on a micro time scale, avoiding screen tearing, flickering or color deviation caused by minute differences in clock speed.

[0066] In an optional embodiment, the transmitting device performs link delay measurement during the initialization phase: the transmitting device sends a ranging sequence to each level of receiving device and receives the response from each receiving device to calculate the physical transmission delay value from the transmitting device to each level of receiving device; the transmitting device sends the calculated delay compensation parameters corresponding to each receiving device to the corresponding receiving device; each receiving device performs alignment correction on the generated local vertical synchronization signal according to the corresponding delay compensation parameters, so that the receiving devices at each level in the cascaded link maintain phase alignment during the display driving phase.

[0067] In this embodiment, the transmitting device performs link delay measurement, accurately calculates the physical transmission delay value to each level of receiving device, and sends the delay compensation parameters to the receiving devices. Each receiving device aligns and corrects its local vertical synchronization signal according to the parameters, ensuring that each level of receiving device in the cascaded link maintains phase alignment during the display driving stage, thereby improving the display synchronization and stability of the LED display control system.

[0068] This embodiment constructs a precise synchronization system. The first step is "measurement": During system startup or recalibration, the transmitting device, as the master controller, actively initiates a "link delay measurement" process. It sequentially sends a special "ranging sequence" data packet to each receiving device in the daisy chain and waits for a response from each device. Since data relay processing in the physical cable and at each level of the device takes time, the transmitting device can accurately calculate the one-way "physical transmission delay value" from the transmitting device to each receiving device by calculating the round-trip time from "sending command" to "receiving response" and combining it with the known internal processing delay of the receiving device. This delay value includes the inherent delay of signal transmission in each segment of the DP cable. The second step is "compensation". The transmitting device sends the calculated unique "delay compensation parameters" for each receiving device to the corresponding device. When generating a local vertical synchronization signal (Vsync), each receiving device does not simply follow the synchronization feature code extracted from the data stream, but actively and precisely "aligns and corrects" the generation time of this Vsync signal according to the compensation parameters sent to it. Specifically, the farther the receiving device is from the transmitting device, the longer the cumulative transmission delay its signal experiences. To ensure that the farthest pixels on the screen begin displaying a new frame at the same absolute moment, the farthest device needs to advance (lead compensation) its Vsync signal, while the nearthest device may need to slightly delay (lag compensation) its Vsync signal. Through this "peak-shaving and valley-filling" active correction, the Vsync signals generated by all cascaded devices and used to actually drive the display are ultimately perfectly aligned in time phase.

[0069] In an optional embodiment, the custom protocol message is sent using a broadcast or multicast address; each receiving device has a unique physical location identifier pre-stored and is configured to filter and extract display data pointing to its own device from the broadcast or multicast custom protocol message based on the physical location identifier.

[0070] In this embodiment, the receiving device can accurately filter the display data payload pointing to its own device from the custom protocol messages broadcast or multicast, effectively avoiding data chaos and improving the accuracy and efficiency of data transmission. This embodiment provides an intelligent data distribution mechanism based on logical addressing. Its core principle is: under the "one-to-many" communication model, a unique "physical location identifier" is pre-assigned to each receiving device as its logical address, and each receiving device actively "claims" its own data from the globally broadcast data stream based on this address, thereby achieving accurate, one-to-one data delivery without the sending end maintaining an independent point-to-point data stream for each device. The sending device encapsulates all display data and control information into a large and comprehensive "custom protocol message," which is sent using a broadcast or multicast address. The message contains addressing information, enabling the receiving device to determine which part of the data in the message belongs to it. Each receiving device is pre-stored with a unique "physical location identifier" (such as "(row, column)" coordinates, device serial number, or logical ID) during factory or system configuration. When it receives a broadcast message, it first parses the message's addressing information and then compares it with its own pre-stored identifier. Once a match is found, it precisely "filters and extracts" the portion of display data specifically targeting its own device from the message's large data payload area based on the addressing information (such as offset and length). The remaining data that does not belong to it is ignored or transparently relayed.

[0071] In an optional embodiment, the receiving device further includes a video processing unit and a frame memory. The video processing unit is configured to receive and extract display data belonging to the receiving device at this level from the main link, perform image processing on the extracted display data and write the result into the frame memory, and read data from the frame memory under display timing control and send it to the constant current source driver chip corresponding to the receiving device at this level to drive the LED display module to display.

[0072] In this embodiment, the video processing unit of the receiving device can extract the display data of its own level from the main link and perform image processing. The results are stored in a frame buffer, and then, under display timing control, the data is read and sent to the constant current source driver chip to drive the corresponding LED display module. This achieves effective processing and visualization output of the display data. By setting up a video processing unit and a frame buffer in the receiving device, a complete display control architecture of "data extraction - image processing - frame buffering - timing output" is constructed. The video processing unit extracts the display data of its own responsible area from the overall image of the DP main link, performs image processing such as correction and splicing, and writes it into the frame buffer. The video processing unit can perform real-time brightness and chromaticity correction on the extracted display data according to the point-by-point correction coefficients pre-stored in the local non-volatile memory to eliminate moiré patterns and uneven color blocks on the LED display screen. Then, it reads the data according to the LED driving timing and outputs it to the constant current source driver chip. Ultimately, this achieves the technical effects of precise screen partitioning in the cascaded system, asynchronous decoupling of image processing and display, stable and controllable output timing, and seamless splicing and synchronous display of the entire screen, ensuring high-quality image output for ultra-large resolution LED displays.

[0073] In an optional embodiment, the transmitting device dynamically adjusts the display parameters based on the returned auxiliary signal. When the temperature of the target receiving device exceeds a safety threshold, it automatically reduces the driving current of the LED beads in the corresponding area of ​​the target receiving device or reduces the refresh rate to reduce heat generation. The system also supports remote cloud monitoring. The transmitting device packages and uploads the status information of all receiving devices it collects to the cloud server. Maintenance personnel can view the operating status of the LED display in real time through a mobile terminal or web interface and issue remote calibration commands. After the remote calibration command reaches the transmitting device via the Internet, it is then sent to the target receiving device through the auxiliary channel differential line pair of the auxiliary channel.

[0074] In this embodiment, the display parameters can be dynamically adjusted according to the feedback auxiliary signal. When the temperature of the target receiving device exceeds the safety threshold, the driving current or refresh rate of the LED beads in the corresponding area is reduced to reduce heat generation. Remote cloud monitoring is also supported, and maintenance personnel can view the operating status of the display screen in real time and issue calibration commands. The calibration commands are issued using the auxiliary channel differential line pair.

[0075] Based on the returned temperature and other auxiliary signals, the transmitting device automatically reduces current or refresh rate for overheating receiving devices, achieving hardware safety protection. Simultaneously, it uploads the entire system status to the cloud, allowing maintenance personnel to remotely monitor via mobile terminals or web interfaces. Calibration commands are then sent from the cloud to the target receiving device via the transmitting device. The system also supports remote cloud monitoring. The transmitting device packages and uploads the status information of all receiving devices to the cloud server, allowing maintenance personnel to view the LED display's operating status in real time via mobile terminals or web interfaces and issue remote calibration commands. These remote calibration commands reach the transmitting device via the internet and are then sent to the target receiving device through the differential lines of the auxiliary channel. This remote monitoring and calibration function facilitates the management and maintenance of the entire LED display system, improving work efficiency and system reliability. It solves the problems of large LED display systems lacking local intelligent temperature control, passive fault exposure, reliance on on-site manual maintenance, and lack of remote control capabilities, overcoming the limitations of traditional auxiliary channels that can only send uplink commands. Ultimately, this system achieves proactive safety protection, unattended intelligent operation, full-domain remote real-time monitoring, and remote online precise calibration, significantly reducing maintenance costs and failure risks while enhancing system intelligence and reliability. It not only effectively prevents hardware damage and light decay caused by localized overheating but also substantially reduces maintenance costs and improves system reliability and intelligence, reaching the technological heights of "intelligent operation and maintenance" for display terminals in the Industry 4.0 era.

[0076] In an optional embodiment, both the transmitting device and the receiving device include encoding and decoding logic units for implementing Manchester encoding. During encoding, the encoding and decoding logic units transform the original binary data stream into a signal waveform that does not contain a DC component and undergoes a level transition at the midpoint of each symbol period. During decoding, the original data 0 or 1 is recovered by detecting the level transition direction of the signal waveform at the midpoint of the symbol period, and a self-synchronizing clock signal is extracted from the transition.

[0077] In this embodiment, the encoding / decoding logic unit transforms the original binary data stream into a signal waveform that contains no DC component and undergoes a level transition at the midpoint of each symbol period during encoding, thus avoiding the influence of DC components on signal transmission. During decoding, the original data is recovered by detecting the direction of the level transition and the self-synchronizing clock signal is extracted, which helps ensure that the auxiliary signal is accurately transmitted at a rate of no less than 100 megabits per second in the daisy-chain topology. This aims to solve the problems of difficult clock synchronization, signal drift caused by DC component accumulation, synchronization errors after long-distance transmission, high bit error rate, and increased wiring complexity due to the need for an independent clock line in traditional encoding methods in high-speed auxiliary signal transmission. Combined with the high-speed auxiliary channel circuit architecture in the aforementioned embodiment, the auxiliary channel still has the advantages of strong anti-interference, self-synchronization, no DC accumulation, and low bit error rate at a transmission rate of 100 Mbps, ensuring stable and reliable transmission of auxiliary signals in large-scale daisy-chain cascading. Traditional NRZ (non-return-to-zero) encoding generates a DC component when transmitting consecutive "1"s or "0"s, which will cause signal waveform distortion (such as amplitude attenuation and duty cycle distortion) after passing through the AC coupling circuit. This solution eliminates DC components through Manchester encoding, ensuring signal integrity after passing through isolation transformers or long cables. Without a dedicated clock line, it's difficult for the receiver to extract an accurate clock from the data stream. Traditional methods rely on complex phase-locked loops to track data edges, making them highly sensitive to consecutive "0"s or "1"s. This solution utilizes the characteristic that each symbol has a transition, making clock extraction extremely simple and reliable, eliminating phase jitter. Due to its self-synchronization capability, the system is highly adaptable to variations in transmission cable length and signal attenuation, improving the product's versatility and stability.

[0078] The following description, in conjunction with specific embodiments, illustrates this approach. This application provides an LED display control system and communication method based on a DP physical link, specifically proposing a customized DP link protocol architecture, including the following: 1. Link Alternatives Standard DP cables are used as the physical interconnection medium, and the DP MainLink is used to transmit high-speed video downlink data as well as control and configuration data.

[0079] Instead of the traditional Ethernet RJ45 interconnection method, DP cables are used to achieve cascading between receiving cards (DaisyChain).

[0080] Detached from the limitations of the standard DP video transmission protocol, a lightweight data frame structure is defined specifically for LED display systems. The transmitting device encapsulates video pixel data and control information within a custom message and distributes it via physical links in broadcast or multicast formats. Each receiving device (such as a receiver card) extracts the corresponding pixel slice data and control information as needed based on a preset address index.

[0081] The system introduces a global broadcast synchronization mechanism. The transmitting device periodically injects a synchronization signature into the link. Each receiving device at each level captures this signature and constructs a local high-performance pixel clock using internal logic. This clock directly drives the constant current source driver chip, ensuring phase consistency between grayscale scanning and pulse width modulation (PWM) across the entire screen. Based on the local reference clock, each receiving device dynamically calibrates its local display clock by detecting and tracking the periodically transmitted global synchronization signature, ensuring the local display clock frequency is always locked to the transmitting end. This generates a local display clock that is consistent with the transmitting device's clock frequency and is tracked and corrected in real time.

[0082] During the initialization phase, the system automatically detects the physical transmission delay between the transmitter and each level of the receiver card through round-trip ranging. Based on the measured absolute delay, the receiver card performs precise lead / lag compensation on the global synchronization signal to generate a compensated local vertical synchronization signal (Vsync), achieving full-screen display alignment.

[0083] The sending end can configure the physical location mapping of each display module, the brightness / color correction coefficient of the LED beads, the constant current source drive current level and various monitoring thresholds online through point-to-point or multicast addressing, so as to realize in-depth digital management of the display wall.

[0084] 2. AUX bus physical layer circuit modification Circuit architecture: The pull-up and pull-down resistors in the standard DP protocol are removed, and the AC coupling architecture is still used.

[0085] Advantages: Eliminates redundant load and impedance interference, significantly improves high-speed transmission performance, and is perfectly suited for 100Mbps long-distance applications.

[0086] 3. Optimization of auxiliary encoding protocols Manchester encoding is used on the modified AUX physical channel.

[0087] Technical benefits: It increases the original 1Mbps AUX bandwidth to 100Mbps, enabling real-time high-speed backhaul of data from dozens or even hundreds of receiving cards, without the need for additional cables.

[0088] The LED display control system (or LED display cascade system) based on the DP physical link in this embodiment uses DP cables as the data transmission carrier, and the transmitting end (corresponding to the aforementioned transmitting device) and the receiving end (corresponding to the aforementioned receiving device), as well as the receiving end and the receiving end, are directly connected through DP cables; the auxiliary channel (AUX) in the DP cable adopts an improved AC coupling method for data return; the pull-up and pull-down resistors in the standard protocol are removed from the AUX bus of the transmitting and receiving ends to reduce signal reflection and ensure the integrity of long-distance transmission signals; the physical layer transmission adopts Manchester encoding to ensure DC balance and self-synchronization clock extraction; the AUX channel supports high-speed transmission, and the return rate can reach more than 100Mbps.

[0089] In terms of architecture, this application's embodiments use DP line cascading instead of network cable cascading, changing the industry wiring logic of LED displays. At the physical layer, a specific combination of "AC coupling + removal of pull-up and pull-down resistors + Manchester encoding" solves the problem of speeding up high-speed, long-distance AUX channels.

[0090] Figure 3 This is a schematic diagram of a standard DP AUX circuit in related technologies, such as... Figure 3 As shown, the configuration circuit of the DP interface includes an AC coupling capacitor (such as...). Figure 3 (C_AUX), pull-up and pull-down resistors, and bias resistors, etc. Pull-up and pull-down resistors include those connected to the power supply terminal (e.g., C_AUX), pull-up and pull-down resistors, etc. Figure 3 The pull-up resistors (DP_PWR, 2.5-3.3V) and the pull-down resistors connected to ground are included. Figure 3 Vbias_Tx and Vbias_Rx are the bias power supply terminals, and the bias resistor is 50Ω; Figure 3 The area between the two dashed lines represents a DP cable, which connects adjacent receiving devices on both sides, or connects a transmitting device and a first-level receiving device on both sides. Each device's DP interface includes a transmitting unit (or transmitting chip Tx) and a receiving unit (or receiving chip Rx). Figure 3 This corresponds to the DP standard AC coupling method, but its drawback is that it cannot support high-speed, long-distance unbalanced bitstreams.

[0091] Figure 4This is a schematic diagram of a DP AUX circuit provided in an embodiment of this application. The receiving unit (corresponding to the aforementioned differential signal receiver, Rx in the figure) and transmitting unit (corresponding to the aforementioned differential signal driver, Tx in the figure) of the DP interface are both connected in series with the DP cable via DC blocking capacitors. The two differential input terminals of the receiving unit are connected in parallel with the two differential output terminals of the transmitting unit. For example, the first differential input terminal of the receiving unit is connected to the first differential output terminal of the transmitting unit, and the second differential input terminal of the receiving unit is connected to the second differential output terminal of the transmitting unit, both connected to the DP cable through DC blocking capacitors. The first and second differential input terminals of the receiving unit are each connected to a bias power supply terminal through a bias resistor. Figure 4 The values ​​Vbias_Tx and Vbias_Rx are used in this application. The DP AUX circuit provided in this embodiment removes the pull-up and pull-down resistors in the DP standard protocol, making it suitable for high-speed transmission.

[0092] Figure 5 This is a schematic diagram of the LED display control system architecture in related technologies. As can be seen, n network cables are required from the LED sending card to the LED display module (or LED screen), which leads to complex wiring and increased system costs. Figure 6 This is an overall architecture diagram of the LED display control system provided in the embodiments of this application, such as... Figure 6 As shown, only one DP cable is needed between the LED sending card and the LED display module. Figure 7 This is a schematic diagram of the connection between the sending card and the receiving card provided in this application embodiment. Node 1 (Sender / Main Control Card): Outputs a high-speed Main Link + modified AUX link. Nodes 2-N (Receiving Cards): Each receiving card integrates dual DP interfaces. Through internal relay logic, it performs Manchester decoding on the AUX signal, extracts monitoring data, and then encodes and forwards it to the next level.

[0093] Backhaul path: Demonstrates how data is transmitted back at high speed from the Nth level receiving card to the main control card.

[0094] Features: For ultra-high definition resolution transmitting card (Tx card) to connect to the display card (Rx card) of the receiving system, only one DP cable is required, while the traditional solution requires dozens of network cables. This application can significantly reduce the complexity of wiring.

[0095] The embodiments of this application have at least the following advantages: Minimal cabling: One DP cable replaces multiple network cables, significantly reducing the load on the transmitter interface; High-performance backhaul: It solves the problem of insufficient backhaul bandwidth in LED cascade systems with related technologies, and supports large-scale real-time monitoring and data backhaul; Low cost: No expensive fiber optic cables or additional Ethernet PHY chips are required; high-speed data links can be achieved with simple resistor matching.

[0096] This application also provides an LED display control method, applicable to the LED display control system of any of the foregoing embodiments, such as... Figure 8 As shown, the process includes: Step S801: The transmitting device is directly connected to the primary receiving device and the adjacent receiving device in sequence through DP cables to form a daisy-chain topology. Each DP cable contains a main link differential pair for transmitting display data and an auxiliary channel differential pair for transmitting auxiliary signals. Step S802: Configure the auxiliary signal interface circuit inside the transmitting device and each receiving device, so that the auxiliary signal interface circuit and the auxiliary channel differential line pair are connected by an AC coupling connection structure with the pull-up and pull-down resistors removed. In step S803, the transmitting device transmits display data in a daisy-chain topology using the main link differential pairs in the DP cable, and the receiving device transmits auxiliary signals in a daisy-chain topology using Manchester encoding using the auxiliary channel differential pairs in the DP cable.

[0097] Through the above steps, the efficient construction and signal transmission of the LED display control system were achieved. The use of a daisy-chain topology and DP cable connection simplified wiring; the improved AUX channel and Manchester encoding enhanced the return bandwidth and efficiency of auxiliary signals. Strict execution and monitoring of each step ensured stable system operation, resulting in significant improvements in wiring simplification and signal transmission efficiency compared to existing technologies.

[0098] In an optional embodiment, the method further includes: the sending device encapsulates display data and control information into a custom protocol message, and periodically inserts a global synchronization feature code into the custom protocol message; the sending device sends the custom protocol message to each receiving device level by level through the main link of the DP cable; each receiving device generates an aligned local control signal according to the global synchronization feature code and a preset delay compensation coefficient; each receiving device extracts the target display data corresponding to each receiving device and drives the display according to the address offset in the custom protocol message.

[0099] In this embodiment, the transmitting device encapsulates display data and control information into a custom protocol message and inserts a global synchronization feature code to ensure the integrity and standardization of data received by each receiving device. By sending the message down level by level through the main link, effective transmission of display data in the daisy-chain topology can be achieved. The transmitting device sends the custom protocol message carrying the global synchronization feature code through the differential line of the main link. Each receiving device performs dynamic frequency calibration of its local reference clock according to the global synchronization feature code to generate a local display clock synchronized with the transmitting end frequency to drive the display scanning timing of its level.

[0100] Each receiving device generates aligned local control signals based on the global synchronization feature code and delay compensation coefficient, ensuring the synchronization of each receiving device. The target display data is extracted based on the address offset and the display is driven, which can accurately allocate the display data to the corresponding receiving device, realizing efficient and accurate display of the LED display control system.

[0101] The above method also includes: each receiving device relays and integrates Manchester-encoded auxiliary signals through auxiliary channel differential pairs, and aggregates the return data from the receiving device at this level and the next level to the transmitting device step by step; the transmitting device sends a ranging sequence and measures the transmission delay at each level during the initialization phase, and sends delay compensation parameters to each receiving device according to the delay calculation results, so that the display synchronization signals of each receiving device are phase aligned.

[0102] It should be noted that the system and method embodiments provided in the above embodiments belong to the same concept. Other method embodiments correspond to the aforementioned system embodiments. Other technical features can be found in the previous embodiments and will not be repeated here.

[0103] The above description is merely an exemplary embodiment of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Other embodiments of this disclosure will be readily apparent to those skilled in the art upon consideration of the disclosure herein.

[0104] This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art that are not described in this disclosure.

Claims

1. An LED display control system, characterized in that, include: Transmitting equipment and multi-level receiving equipment; The transmitting device and the first-level receiving device, as well as two adjacent receiving devices, are all directly connected via DP cables to form a daisy-chain topology. Each of the DP cables includes a main link differential pair for transmitting display data and an auxiliary channel differential pair for transmitting auxiliary signals. Each of the transmitting devices and each of the receiving devices is provided with an auxiliary signal interface circuit. The auxiliary signal interface circuit and the auxiliary channel differential line pair adopt an AC coupling connection structure, and the pull-up and pull-down resistors configured in the standard DP interface are removed. The system is configured to use the auxiliary channel differential line pair to transmit auxiliary signals in the daisy-chain topology, and to use Manchester encoding when transmitting the auxiliary signals to support a transmission rate of 100 megabits per second or higher.

2. The system according to claim 1, characterized in that, Each receiving device at each level integrates dual DP interfaces, including a first DP interface and a second DP interface. The first DP interface is used to receive downlink display data transmitted by the transmitting device or the receiving device at the previous level via a DP cable, and the second DP interface is used to forward the downlink display data to the receiving device at the next level. Alternatively, the second DP interface is used to receive auxiliary signals from the receiving device at the next level transmitted via a DP cable, and the first DP interface is used to integrate the return signal of this level and the auxiliary signal of the receiving device at the next level before forwarding it to the receiving device at the previous level. Finally, all auxiliary signals converge to the transmitting device.

3. The system according to claim 1, characterized in that, The auxiliary signal interface circuit includes a differential signal driver and a differential signal receiver. Both the differential signal driver and the differential signal receiver are connected to the differential line pair of the auxiliary channel via AC coupling. The AC coupling architecture includes: DC blocking capacitors connected in series on the connection path between the output terminal of the differential signal driver and the DP cable, and on the connection path between the input terminal of the differential signal receiver and the DP cable. No resistors are connected to either the side of the DC blocking capacitor closest to the differential signal driver or the side of the DC blocking capacitor closest to the differential signal receiver to pull the signal level up to the power supply voltage or down to ground potential. The auxiliary signal interface circuit further includes a first bias resistor and a second bias resistor, wherein the first differential output terminal of the differential signal driver is connected to the bias power supply terminal through the first bias resistor, and the second differential output terminal of the differential signal driver is connected to the bias power supply terminal through the second bias resistor; the first differential input terminal of the differential signal receiver is connected to the first differential output terminal of the differential signal driver, and the second differential input terminal of the differential signal receiver is connected to the second differential output terminal of the differential signal driver.

4. The system according to claim 1, characterized in that, The receiving device has a built-in relay processing unit, which is configured to decode the encoded auxiliary signal received from the next-level receiving device through the auxiliary channel differential line, extract the return data of the next-level receiving device from the decoded signal, integrate the return data of the current receiving device with the return data of the next-level receiving device, perform Manchester encoding, and then forward it to the next-level receiving device or the transmitting device through the auxiliary signal interface circuit of the current receiving device.

5. The system according to claim 4, characterized in that, The return data transmitted through the auxiliary channel includes at least one of the following: operating status monitoring data of the receiving device, temperature data, brightness data, voltage of the power supply circuit, fault detection data of the LED display module, and coefficient data for LED display color and brightness uniformity correction.

6. The system according to claim 1, characterized in that, The receiving device is electrically connected to the constant current source driver chip of the corresponding LED display module. After parsing and converting the received display data, the receiving device transmits the processed drive signal to the constant current source driver chip. The constant current source driver chip provides a constant operating current to the corresponding LED display module's LED beads according to the drive signal, thereby realizing the visual output of the display data.

7. The system according to claim 1, characterized in that, The transmitting device is configured to encapsulate the display data and control information into a custom protocol message and send it to the receiving device via the main link of the DP cable in a broadcast or multicast manner; the transmitting device is also configured to periodically insert a global synchronization feature code into the custom protocol message; Each receiving device is used to extract corresponding pixel data from the custom protocol message, and perform dynamic frequency tracking calibration of the local reference clock according to the global synchronization feature code to generate a local display clock synchronized with the clock frequency of the transmitting device, so as to drive the display scanning timing of the device at this level.

8. The system according to claim 7, characterized in that, The transmitting device performs link delay measurement during the initialization phase: the transmitting device sends a ranging sequence to each level of the receiving device and receives the response from each of the receiving devices to calculate the physical transmission delay value from the transmitting device to each level of the receiving device; The transmitting device sends the calculated delay compensation parameters corresponding to each receiving device to the corresponding receiving device. Each receiving device performs alignment correction on the generated local vertical synchronization signal according to the corresponding delay compensation parameter, so that the receiving devices at each stage in the cascaded link maintain phase alignment during the display driving phase.

9. The system according to claim 7, characterized in that, The custom protocol messages are sent using broadcast or multicast addresses; each receiving device at each level has a unique physical location identifier and is configured to filter and extract display data pointing to its own device from the broadcast or multicast custom protocol messages based on the physical location identifier.

10. An LED display control method, characterized in that, The LED display control system applied in any one of claims 1 to 9 includes: The transmitting device is directly connected to the primary receiving device and adjacent receiving devices in sequence through DP cables to form a daisy-chain topology. Each of the DP cables includes a main link differential pair for transmitting display data and an auxiliary channel differential pair for transmitting auxiliary signals. Configure the auxiliary signal interface circuit inside the transmitting device and each of the receiving devices so that the auxiliary signal interface circuit and the auxiliary channel differential line pair are connected by an AC coupling connection structure with pull-up and pull-down resistors removed; The transmitting device uses the main link differential pair in the DP cable to transmit display data in the daisy-chain topology, and the receiving device uses the auxiliary channel differential pair in the DP cable to transmit auxiliary signals in the daisy-chain topology using Manchester encoding.

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