A signal switching system and method

Abstract

The application discloses a signal switching system and method, wherein a main control module generates a low-level control signal when the working mode of a target display module is HDMI2.1 mode, generates a high-level control signal when the working mode of the target display module is HDMI2.1 mode below, and disconnects a direct current bias module when the control signal is low-level, so that the output end of an alternating current coupling module outputs an alternating current coupled HDMI signal to the target display module, which meets the HDMI2.1 mode specification; when the control signal is high-level, the direct current bias module is turned on, at this time, the direct current bias module and the pull-up resistor of the target display module form a direct current bias, so that the target display module receives a direct current coupled HDMI signal, which meets the HDMI2.1 mode below specification, thereby realizing the compatibility of a single product to HDMI2.1 mode and HDMI2.1 mode below, and improving the usability and reliability of the single product.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a signal switching system and method. Background Technology

[0002] With the continuous development of audio and video technology, people's requirements for video image quality are getting higher and higher. High Definition Multimedia Interface (HDMI) video transmission boasts widespread adoption and ease of cabling, making it an indispensable video signal transmission technology in the audio and video transmission field. With the updates and iterations of the HDMI protocol, HDMI's transmission rate is also increasing. HDMI has now evolved to the HDMI 2.1 standard. According to the HDMI 2.1 standard, HDMI 2.1 operates in Fixed Rate Link (FRL) mode, while when switching to HDMI 2.0 and earlier modes, HDMI operates in Transition Minimize Differential Signaling (TMDS) mode, and the resistance to ground in the HDMI signal transmission path needs to form a DC bias with the pull-up resistor at the sink. Furthermore, TMDS mode often uses DC coupling, while according to the HDMI 2.1 standard, HDMI 2.1 requires AC coupling. In summary, the FRL-based HDMI 2.1 mode is not backward compatible with TMDS-based HDMI 2.0 and earlier modes, resulting in low usability and reliability of products based on a single HDMI mode. When switching HDMI modes, these products cannot pass the HDMI Compliance Test Specification (CTS) certification. Summary of the Invention

[0003] The purpose of this invention is to at least partially solve one of the technical problems existing in the prior art.

[0004] Therefore, embodiments of the present invention provide a signal switching system and method that achieves compatibility with HDMI 2.1 mode and modes below HDMI 2.1.

[0005] To achieve the above-mentioned technical objectives, the technical solutions adopted in the embodiments of the present invention include:

[0006] On one hand, embodiments of the present invention provide a signal switching system, including a main control module and a signal switching circuit;

[0007] The main control module is used to generate control signals according to the working mode of the target display module. The working mode includes HDMI 2.1 mode and HDMI 2.1 and below mode. If the working mode is HDMI 2.1 mode, the control signal is low level; if the working mode is HDMI 2.1 and below mode, the control signal is high level.

[0008] The signal switching circuit includes an AC coupling module and a DC bias module. The input terminal of the AC coupling module is connected to the first output terminal of the main control module, which is used to output an HDMI signal. The output terminal of the AC coupling module is used to output the AC-coupled HDMI signal to the target display module. The first terminal of the DC bias module is connected to the input terminal of the AC coupling module, the second terminal of the DC bias module is grounded, and the third terminal of the DC bias module is connected to the second output terminal of the main control module. The second output terminal of the main control module is used to output the control signal. If the control signal is high, the DC bias module is turned on; if the control signal is low, the DC bias module is turned off.

[0009] In addition, a signal switching system according to the above embodiments of the present invention may also have the following additional technical features:

[0010] Furthermore, in a signal switching system according to an embodiment of the present invention, the main control module includes a protocol interpretation module and a control signal generation module;

[0011] The protocol interpretation module obtains the extended display identifier data of the target display module and determines the working mode of the target display module based on the extended display identifier data. If the working mode is HDMI 2.1 mode, the control signal generation module generates the control signal and configures the control signal to a low level; if the working mode is HDMI 2.1 or lower mode, the control signal generation module generates the control signal and configures the control signal to a high level.

[0012] Furthermore, in one embodiment of the present invention, the protocol interpretation module acquires the extended display identification data of the target display module through a bidirectional control bus.

[0013] Furthermore, in one embodiment of the present invention, the AC coupling module includes several sets of first differential lines, the number of sets of first differential lines being the same as the number of sets of the HDMI signal. Each set of first differential lines includes a first line and a second line. A first capacitor is disposed on the first line, and a second capacitor is disposed on the second line. One end of the first differential line is the input terminal of the AC coupling module, and the other end of the first differential line is the output terminal of the AC coupling module.

[0014] Furthermore, in one embodiment of the present invention, the first capacitor and the second capacitor are in a 0201 package.

[0015] Furthermore, in one embodiment of the present invention, the DC bias module includes a plurality of DC bias structures, the number of DC bias structures being the same as the number of the first differential lines. Each DC bias structure includes a set of second differential lines and a switching component. Each set of second differential lines includes a third line and a fourth line. A first resistor is disposed on the third line, and a second resistor is disposed on the fourth line. One end of the second differential line is the first end of the DC bias module, and the other end of the second differential line is connected to the first end of the switching component. The second end of the switching component is the second end of the DC bias module, and the third end of the switching component is the third end of the DC bias module.

[0016] If the control signal is high, the switching component is turned on;

[0017] If the control signal is low, the switching assembly is disconnected.

[0018] Furthermore, in one embodiment of the present invention, the switching component is an NMOS transistor;

[0019] The drain of the NMOS transistor is the first terminal of the switching assembly, the source of the NMOS transistor is the second terminal of the switching assembly, and the gate of the NMOS transistor is the third terminal of the switching assembly.

[0020] On the other hand, embodiments of the present invention propose a signal switching method, which is applied to a signal switching system. The signal switching system includes a main control module and a signal switching circuit. The signal switching circuit includes an AC coupling module and a DC bias module. The signal switching method includes:

[0021] According to the working mode of the target display module, the main control module generates a control signal. The working mode includes HDMI 2.1 mode and HDMI 2.1 and below mode. If the working mode is HDMI 2.1 mode, the control signal is low level; if the working mode is HDMI 2.1 and below mode, the control signal is high level.

[0022] The input terminal of the AC coupling module receives the HDMI signal output from the first output terminal of the main control module, and the third terminal of the DC bias module receives the control signal output from the second output terminal of the main control module.

[0023] If the control signal is high, the DC bias module is turned on; if the control signal is low, the DC bias module is turned off. The first terminal of the DC bias module is connected to the input terminal of the AC coupling module, and the second terminal of the DC bias module is grounded.

[0024] The AC-coupled HDMI signal is output to the target display module through the output terminal of the AC coupling module.

[0025] Furthermore, in one embodiment of the present invention, the main control module includes a protocol interpretation module and a control signal generation module;

[0026] The step of generating control signals through the main control module according to the working mode of the target display module includes:

[0027] The extended display identifier data of the target display module is obtained through the protocol interpretation module, and the working mode of the target display module is obtained based on the extended display identifier data;

[0028] If the operating mode is HDMI 2.1 mode, the control signal generation module generates the control signal and configures the control signal to a low level;

[0029] If the operating mode is below HDMI 2.1, the control signal generation module generates the control signal and configures the control signal to a high level.

[0030] Furthermore, in one embodiment of the present invention, the protocol interpretation module acquires the extended display identification data of the target display module through a bidirectional control bus.

[0031] Advantages and beneficial effects of the present invention:

[0032] This invention relates to a signal switching system and method. The signal switching system includes a main control module and a signal switching circuit. The signal switching circuit includes an AC coupling module and a DC bias module. The main control module generates a low-level control signal when the target display module is in HDMI 2.1 mode and a high-level control signal when the target display module is in an HDMI 2.1 or lower mode. When the control signal is low, the DC bias module is disconnected, allowing the output of the AC coupling module to output an AC-coupled HDMI signal to the target display module, conforming to the HDMI 2.1 specification. When the control signal is high, the DC bias module is turned on. At this time, the DC bias module and the pull-up resistor of the target display module form a DC bias, so that the DC bias voltage is superimposed on the AC-coupled HDMI signal output from the output of the AC coupling module, allowing the target display module to receive a DC-coupled HDMI signal, conforming to the HDMI 2.1 or lower mode specification. This achieves compatibility of a single product with both HDMI 2.1 and HDMI 2.1 and lower modes, improving the usability and reliability of the single product and enabling the single product to pass HDMI CTS certification when switching HDMI modes. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of this application or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions in this application. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0034] Figure 1 This is a schematic diagram of a specific embodiment of the signal switching system of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of the first output terminal of the main control module in a specific embodiment of the signal switching system of the present invention;

[0036] Figure 3 This is a schematic diagram of the signal switching circuit according to a specific embodiment of the signal switching system of the present invention;

[0037] Figure 4 This is a flowchart illustrating a specific embodiment of a signal switching method according to the present invention.

[0038] Reference numerals: 301, AC coupling module; 302, DC bias module. Detailed Implementation

[0039] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0040] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0041] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] With the continuous development of audio and video technology, people's requirements for video image quality are getting higher and higher. HDMI video transmission has strong popularity and simple wiring, making it an indispensable video signal transmission technology in the field of audio and video transmission. With the updates and iterations of the HDMI protocol, the transmission rate of HDMI is also getting higher and higher. HDMI has now evolved to the HDMI 2.1 standard. According to the HDMI 2.1 standard, HDMI 2.1 operates in FRL mode, while when switching to HDMI 2.0 and earlier modes, HDMI operates in TMDS mode, and the resistance to ground of the HDMI signal transmission path needs to form a DC bias with the pull-up resistor at the sink end. In addition, TMDS mode often uses DC coupling, while according to the HDMI 2.1 standard, HDMI 2.1 requires AC coupling. In summary, the FRL-based HDMI 2.1 mode is not backward compatible with the TMDS-based HDMI 2.0 and earlier modes, resulting in low usability and reliability of products based on a single HDMI mode, and failing to pass HDMI CTS certification when switching HDMI modes. To address this issue, the present invention proposes a signal switching system and method. The signal switching system includes a main control module and a signal switching circuit. The signal switching circuit includes an AC coupling module and a DC bias module. The main control module generates a low-level control signal when the target display module is in HDMI 2.1 mode and a high-level control signal when the target display module is in an HDMI 2.1 or lower mode. When the control signal is low, the DC bias module is disconnected, allowing the output of the AC coupling module to output an AC-coupled HDMI signal to the target display module, conforming to the HDMI 2.1 specification. When the control signal is high, the DC bias module is turned on. At this time, the DC bias module and the pull-up resistor of the target display module form a DC bias, thereby superimposing the DC bias voltage with the AC-coupled HDMI signal output from the AC coupling module, allowing the target display module to receive a DC-coupled HDMI signal, conforming to the HDMI 2.1 or lower mode specification. This achieves compatibility of a single product with both HDMI 2.1 and HDMI 2.1 and lower modes, improving the usability and reliability of the single product and enabling the single product to pass HDMI CTS certification when switching HDMI modes.

[0043] The following describes in detail, with reference to the accompanying drawings, a signal switching system and method according to an embodiment of the present invention. First, a signal switching system according to an embodiment of the present invention is described.

[0044] Reference Figure 1 A signal switching system according to an embodiment of the present invention includes a main control module and a signal switching circuit;

[0045] The main control module is used to generate control signals according to the working mode of the target display module. The working modes include HDMI 2.1 mode and HDMI 2.1 and below mode. If the working mode is HDMI 2.1 mode, the control signal is low level; if the working mode is HDMI 2.1 and below mode, the control signal is high level.

[0046] The signal switching circuit includes an AC coupling module 301 and a DC bias module 302. The input terminal of the AC coupling module 301 is connected to the first output terminal of the main control module, which is used to output an HDMI signal. The output terminal of the AC coupling module 301 is used to output an AC-coupled HDMI signal to the target display module. The first terminal of the DC bias module 302 is connected to the input terminal of the AC coupling module 301, the second terminal of the DC bias module 302 is grounded, and the third terminal of the DC bias module 302 is connected to the second output terminal of the main control module. The second output terminal of the main control module is used to output a control signal. If the control signal is high, the DC bias module 302 is turned on; if the control signal is low, the DC bias module 302 is turned off.

[0047] HDMI signals include audio and video signals. According to prior knowledge, HDMI modes below 2.1 transmit uncompressed audio and video signals, while HDMI 2.1 mode can transmit uncompressed audio and video signals, and can also achieve higher resolution image presentation by transmitting compressed audio and video signals.

[0048] Understandably, the main control module can be a single product such as a PC host or a laptop.

[0049] Reference Figure 2 In some embodiments, the first output terminal of the main control module outputs four HDMI signals, wherein HDMI0_TX0P_PORT and HDMI0_TX0N_PORT output the first HDMI signal, HDMI0_TX1P_PORT and HDMI0_TX1N_PORT output the second HDMI signal, HDMI0_TX2P_PORT and HDMI0_TX2N_PORT output the third HDMI signal, and HDMI0_TX4P_PORT and HDMI0_TX4N_PORT output the fourth HDMI signal.

[0050] Based on prior knowledge, HDMI 2.1 operates in FRL mode, which offers higher bandwidth compared to the TMDS mode used in earlier versions of HDMI 2.1, enabling the transmission of higher-quality images. TMDS modes below HDMI 2.1 often use DC coupling, while the HDMI 2.1 standard requires AC coupling. AC coupling allows AC signals to pass while blocking DC signals, whereas DC coupling allows both DC and AC signals to pass through. In an embodiment of the present invention, when the target display module (Sink end) operates in HDMI 2.1 mode, the main control module (Source end) generates a low-level control signal, causing the DC bias module 302 of the signal switching circuit to disconnect. The DC bias module 302 cannot form a DC bias with the pull-up resistor of the target display module. At this time, only the AC coupling module 301 functions. The HDMI signal sent by the main control module is AC-coupled by the AC coupling module 301 and then transmitted to the target display module, conforming to the HDMI 2.1 mode specification. When the target display module operates in a mode below HDMI 2.1, the main control module generates a high-level control signal, causing the DC bias module 302 of the signal switching circuit to conduct. The DC bias module 302 forms a DC bias with the pull-up resistor of the target display module. At this time, the HDMI signal sent by the main control module is AC-coupled by the AC coupling module 301, superimposed with the DC signal formed by the DC bias, and transmitted to the target display module, conforming to the HDMI 2.1 mode specification. This demonstrates that a single product has achieved compatibility with HDMI 2.1 mode and modes below HDMI 2.1, thus improving the usability and reliability of the single product.

[0051] As an optional implementation, the main control module includes a protocol interpretation module and a control signal generation module;

[0052] The protocol interpretation module obtains the extended display identifier data of the target display module and determines the working mode of the target display module based on the extended display identifier data. If the working mode is HDMI 2.1 mode, the control signal generation module generates a control signal and configures the control signal to a low level; if the working mode is HDMI 2.1 or below, the control signal generation module generates a control signal and configures the control signal to a high level.

[0053] The Extended Display Identification Data (EDID) consists of 128 bytes and is a standard for display identification data. EDID is stored in the target display module's DDC memory and contains product information about the target display module, including display functions (such as size, resolution, and synchronization), color space, and detailed resolution / timing information.

[0054] As an optional implementation, the protocol interpretation module uses a bidirectional control bus (such as...) Figure 1 The IIC in the target display module is used to obtain the extended display identifier data.

[0055] Optionally, in some embodiments, the protocol interpretation module reads the EDID of the target display module through the DDC channel.

[0056] As an optional implementation, the AC coupling module 301 includes several sets of first differential lines. The number of sets of first differential lines is the same as the number of sets of HDMI signals. Each set of first differential lines includes a first line and a second line. A first capacitor is provided on the first line, and a second capacitor is provided on the second line. One end of the first differential line is the input terminal of the AC coupling module 301, and the other end of the first differential line is the output terminal of the AC coupling module 301.

[0057] Optionally, refer to Figure 3 In some embodiments, the AC coupling module 301 includes four sets of first differential lines. Each set of first differential lines receives an HDMI signal output from a set of main control modules. The first line and second line in each set of first differential lines are respectively connected to an output port of the first output terminal of the main control module. It is understood that for the first differential lines connected to HDMI0_TX0P_PORT and HDMI0_TX0N_PORT, the first capacitor set on the first line is... Figure 3 C1 in the middle, the second capacitor set on the second line is Figure 3 C2 in the diagram; for the first differential line connected to HDMI0_TX1P_PORT and HDMI0_TX1N_PORT, the first capacitor set on the first line is... Figure 3 C3 in the middle, the second capacitor set on the second line is Figure 3 C4 in the diagram refers to the first differential line connected to HDMI0_TX2P_PORT and HDMI0_TX2N_PORT, where the first capacitor set on the first line is... Figure 3 C5 in the middle, the second capacitor set on the second line is Figure 3 C6 in the diagram refers to the first differential line connected to HDMI0_TX3P_PORT and HDMI0_TX3N_PORT, where the first capacitor set on the first line is... Figure 3 C7 in the middle, the second capacitor set on the second line is Figure 3 C8 in the middle.

[0058] It is understandable that capacitors have the characteristic of blocking DC and passing AC, as referenced... Figure 3Each HDMI signal output by the main control module passes through the capacitors of the AC coupling module 301 and then outputs an HDMI signal that does not contain DC signal at the output of the AC coupling module 301. In other words, the output of the AC coupling module 301 outputs an HDMI signal that has been AC coupled.

[0059] As an optional implementation, the first capacitor and the second capacitor are in a 0201 package.

[0060] In this embodiment of the invention, the first capacitor and the second capacitor are packaged in a 0201 package, which reduces the ESR (equivalent series resistance) and ESL (equivalent series inductance) of the capacitors and reduces the impedance change on the first differential line.

[0061] As an optional implementation, the DC bias module 302 includes a plurality of DC bias structures, the number of which is the same as the number of groups of the first differential lines. Each DC bias structure includes a group of second differential lines and a switching component. Each group of second differential lines includes a third line and a fourth line. A first resistor is provided on the third line, and a second resistor is provided on the fourth line. One end of the second differential line is the first end of the DC bias module 302, and the other end of the second differential line is connected to the first end of the switching component. The second end of the switching component is the second end of the DC bias module 302, and the third end of the switching component is the third end of the DC bias module 302.

[0062] If the control signal is high, the switching component is turned on;

[0063] If the control signal is low, the switching component is turned off.

[0064] Optionally, refer to Figure 3 In some embodiments, the DC bias module 302 includes four DC bias structures: a set of second differential lines is individually connected to a set of first differential lines; a third line in the set of second differential lines is individually connected to a first line in the set of first differential lines; and a fourth line in the set of second differential lines is individually connected to a second line in the set of first differential lines. It is understood that for the second differential lines connected to the first differential lines receiving HDMI signals from HDMI0_TX0P_PORT and HDMI0_TX0N_PORT, the first resistor set on the third line is... Figure 3 R8 in the middle, the second resistor set on the fourth line is Figure 3 R7 in the diagram; for the second differential line connected to the first differential line receiving HDMI signals from HDMI0_TX1P_PORT and HDMI0_TX1N_PORT, the first resistor set on the third line is... Figure 3 R6 in the middle, the second resistor set on the fourth line is Figure 3R5 in the diagram; for the second differential line connected to the first differential line receiving HDMI signals from HDMI0_TX2P_PORT and HDMI0_TX2N_PORT, the first resistor set on the third line is... Figure 3 R4 in the circuit, the second resistor set on the fourth line is Figure 3 R3 in the diagram; for the second differential line connected to the first differential line receiving HDMI signals from HDMI0_TX3P_PORT and HDMI0_TX3N_PORT, the first resistor set on the third line is... Figure 3 R2 in the middle, the second resistor set on the fourth line is Figure 3 R1 in the middle.

[0065] As an optional implementation, the switching component is an NMOS transistor;

[0066] The drain of the NMOS transistor is the first terminal of the switching component, the source of the NMOS transistor is the second terminal of the switching component, and the gate of the NMOS transistor is the third terminal of the switching component.

[0067] It is understandable that when the control signal is high, all NMOS transistors (such as...) Figure 3 When the Q1-Q4 transistors are turned on, the pull-up resistor of the target display module and the resistor in the DC bias module 302 form a voltage divider circuit (DC bias), which conforms to the HDMI 2.1 and earlier mode specifications. When the control signal is low, all NMOS transistors are not turned on. At this time, the pull-up resistor of the target display module cannot form a voltage divider circuit (DC bias) with the resistor in the DC bias module 302. The HDMI signal sent by the main control module is AC coupled through the AC coupling module 301 and then transmitted to the target display module, which conforms to the HDMI 2.1 mode specification.

[0068] Optionally, in some embodiments, the first resistor and the second resistor are equal, both being 499Ω, the pull-up resistor of the target display module is 50Ω, and the DC bias voltage formed by the DC bias module 302 and the pull-up resistor of the target display module is 3.3×499 / (499+50)=3V.

[0069] In summary, the signal switching system of this invention generates a low-level control signal when the target display module is in HDMI 2.1 mode and a high-level control signal when the target display module is in an HDMI 2.1 or lower mode. When the control signal is low, the DC bias module 302 is disconnected, allowing the output of the AC coupling module 301 to output an AC-coupled HDMI signal to the target display module, conforming to the HDMI 2.1 specification. When the control signal is high, the DC bias module 302 is turned on. At this time, the DC bias module 302 and the pull-up resistor of the target display module form a DC bias, thereby superimposing the DC bias voltage with the AC-coupled HDMI signal output from the output of the AC coupling module 301. This allows the target display module to receive a DC-coupled HDMI signal, conforming to the HDMI 2.1 or lower mode specification. This achieves compatibility of a single product with both HDMI 2.1 and HDMI 2.1 and lower modes, improving the usability and reliability of the single product and enabling it to pass HDMI CTS certification when switching HDMI modes.

[0070] Secondly, refer to Figure 4 This invention proposes a signal switching method applied to a signal switching system. The signal switching system includes a main control module and a signal switching circuit. The signal switching circuit includes an AC coupling module and a DC bias module. The signal switching method includes:

[0071] S410. Based on the working mode of the target display module, the main control module generates control signals;

[0072] The operating modes include HDMI 2.1 mode and HDMI 2.1 and below mode. If the operating mode is HDMI 2.1 mode, the control signal is low level; if the operating mode is HDMI 2.1 and below mode, the control signal is high level.

[0073] Optionally, in some embodiments, the main control module includes a protocol interpretation module and a control signal generation module, and step S410 can be further divided into the following steps S411-S413:

[0074] Step S411: Obtain the extended display identifier data of the target display module through the protocol interpretation module, and obtain the working mode of the target display module based on the extended display identifier data;

[0075] The Extended Display Identifier (EDID) data, comprising 128 bytes, is a standard for identifying the display. Stored in the target display module's DDC memory, the EDID contains product information about the target display module, including display functions (such as size, resolution, and synchronization), color space, and detailed resolution / timing information. In essence, after obtaining the EDID data of the target display module through the protocol interpretation module, it's possible to identify whether the target display module is operating in HDMI 2.1 mode or a mode below HDMI 2.1 based on the EDID data.

[0076] Optionally, in some embodiments, the protocol interpretation module obtains the extended display identifier data of the target display module through a bidirectional control bus.

[0077] Optionally, in some embodiments, the protocol interpretation module reads the EDID of the target display module through the DDC channel.

[0078] Step S412: If the working mode is HDMI 2.1 mode, the control signal generation module generates a control signal and configures the control signal to low level;

[0079] Step S413: If the working mode is HDMI 2.1 or below, the control signal generation module generates a control signal and configures the control signal to a high level.

[0080] S420: Receives the HDMI signal output from the first output terminal of the main control module through the input terminal of the AC coupling module, and receives the control signal output from the second output terminal of the main control module through the third terminal of the DC bias module.

[0081] HDMI signals include audio and video signals. According to prior knowledge, HDMI modes below 2.1 transmit uncompressed audio and video signals, while HDMI 2.1 mode can transmit uncompressed audio and video signals, and can also achieve higher resolution image presentation by transmitting compressed audio and video signals.

[0082] S430. If the control signal is high, the DC bias module is turned on; if the control signal is low, the DC bias module is turned off.

[0083] The first terminal of the DC bias module is connected to the input terminal of the AC coupling module, and the second terminal of the DC bias module is grounded.

[0084] S440: Outputs an AC-coupled HDMI signal to the target display module through the output terminal of the AC coupling module.

[0085] Based on prior knowledge, HDMI 2.1 operates in FRL mode, which offers higher bandwidth compared to the TMDS mode used in earlier versions of HDMI 2.1, enabling the transmission of higher-quality images. TMDS modes below HDMI 2.1 often use DC coupling, while the HDMI 2.1 standard requires AC coupling. AC coupling allows AC signals to pass while blocking DC signals, whereas DC coupling allows both DC and AC signals to pass through. In embodiments of the present invention, when the target display module operates in HDMI 2.1 mode, the main control module generates a low-level control signal, causing the DC bias module of the signal switching circuit to disconnect. The DC bias module cannot form a DC bias with the pull-up resistor of the target display module. At this time, only the AC coupling module functions. The HDMI signal sent by the main control module is AC-coupled by the AC coupling module and then transmitted to the target display module, conforming to the HDMI 2.1 mode specification. When the target display module operates in a mode below HDMI 2.1, the main control module generates a high-level control signal, causing the DC bias module of the signal switching circuit to conduct. The DC bias module forms a DC bias with the pull-up resistor of the target display module. At this time, the HDMI signal sent by the main control module is AC-coupled by the AC coupling module, superimposed with the DC signal formed by the DC bias, and transmitted to the target display module, conforming to the HDMI 2.1 and below mode specification. Therefore, a single product achieves compatibility with both HDMI 2.1 and HDMI 2.1 and below modes, improving the usability and reliability of the single product.

[0086] The content of the above method embodiments is applicable to this system embodiment. The specific functions implemented in this system embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0087] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and sub-operations described as part of a larger operation are executed independently.

[0088] Furthermore, although this application is described in the context of functional modules, it should be understood that, unless otherwise stated to the contrary, one or more of the functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding this application. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of conventional technology for an engineer. Therefore, those skilled in the art can implement the application set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of this application, which is determined by the full scope of the appended claims and their equivalents.

[0089] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable program execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0090] In the foregoing description of this specification, the references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0091] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

[0092] The above is a detailed description of the preferred embodiments of this application, but this application is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A signal switching system, characterized in that, Includes the main control module and signal switching circuit; The main control module is used to generate control signals according to the working mode of the target display module. The working mode includes HDMI 2.1 mode and HDMI 2.1 and below mode. If the working mode is HDMI 2.1 mode, the control signal is low level; if the working mode is HDMI 2.1 and below mode, the control signal is high level. The signal switching circuit includes an AC coupling module and a DC bias module. The input terminal of the AC coupling module is connected to the first output terminal of the main control module, which is used to output an HDMI signal. The output terminal of the AC coupling module is used to output the AC-coupled HDMI signal to the target display module. The first terminal of the DC bias module is connected to the input terminal of the AC coupling module, the second terminal of the DC bias module is grounded, and the third terminal of the DC bias module is connected to the second output terminal of the main control module. The second output terminal of the main control module is used to output the control signal. If the control signal is high, the DC bias module is turned on; if the control signal is low, the DC bias module is turned off.

2. The signal switching system according to claim 1, characterized in that, The main control module includes a protocol interpretation module and a control signal generation module; The protocol interpretation module obtains the extended display identifier data of the target display module and determines the working mode of the target display module based on the extended display identifier data. If the working mode is HDMI 2.1 mode, the control signal generation module generates the control signal and configures the control signal to a low level; if the working mode is HDMI 2.1 or lower mode, the control signal generation module generates the control signal and configures the control signal to a high level.

3. The signal switching system according to claim 2, characterized in that, The protocol interpretation module obtains the extended display identifier data of the target display module through a bidirectional control bus.

4. The signal switching system according to claim 1, characterized in that, The AC coupling module includes several sets of first differential lines. The number of sets of first differential lines is the same as the number of sets of HDMI signals. Each set of first differential lines includes a first line and a second line. A first capacitor is provided on the first line, and a second capacitor is provided on the second line. One end of the first differential line is the input terminal of the AC coupling module, and the other end of the first differential line is the output terminal of the AC coupling module.

5. A signal switching system according to claim 4, characterized in that, The first capacitor and the second capacitor are in 0201 package.

6. A signal switching system according to claim 4, characterized in that, The DC bias module includes several DC bias structures, the number of which is the same as the number of the first differential lines. Each DC bias structure includes a set of second differential lines and a switching component. Each set of second differential lines includes a third line and a fourth line. A first resistor is provided on the third line, and a second resistor is provided on the fourth line. One end of the second differential line is the first end of the DC bias module, and the other end of the second differential line is connected to the first end of the switching component. The second end of the switching component is the second end of the DC bias module, and the third end of the switching component is the third end of the DC bias module. If the control signal is high, the switching component is turned on; If the control signal is low, the switching assembly is disconnected.

7. A signal switching system according to claim 6, characterized in that, The switching component is an NMOS transistor; The drain of the NMOS transistor is the first terminal of the switching assembly, the source of the NMOS transistor is the second terminal of the switching assembly, and the gate of the NMOS transistor is the third terminal of the switching assembly.

8. A signal switching method, characterized in that, The method is applied to a signal switching system, which includes a main control module and a signal switching circuit. The signal switching circuit includes an AC coupling module and a DC bias module. The signal switching method includes: According to the working mode of the target display module, the main control module generates a control signal. The working mode includes HDMI 2.1 mode and HDMI 2.1 and below mode. If the working mode is HDMI 2.1 mode, the control signal is low level; if the working mode is HDMI 2.1 and below mode, the control signal is high level. The input terminal of the AC coupling module receives the HDMI signal output from the first output terminal of the main control module, and the third terminal of the DC bias module receives the control signal output from the second output terminal of the main control module. If the control signal is high, the DC bias module is turned on; if the control signal is low, the DC bias module is turned off. The first terminal of the DC bias module is connected to the input terminal of the AC coupling module, and the second terminal of the DC bias module is grounded. The AC-coupled HDMI signal is output to the target display module through the output terminal of the AC coupling module.

9. A signal switching method according to claim 8, characterized in that, The main control module includes a protocol interpretation module and a control signal generation module; The step of generating control signals through the main control module according to the working mode of the target display module includes: The extended display identifier data of the target display module is obtained through the protocol interpretation module, and the working mode of the target display module is obtained based on the extended display identifier data; If the operating mode is HDMI 2.1 mode, the control signal generation module generates the control signal and configures the control signal to a low level; If the operating mode is below HDMI 2.1, the control signal generation module generates the control signal and configures the control signal to a high level.

10. A signal switching method according to claim 9, characterized in that, The protocol interpretation module acquires the extended display identifier data of the target display module through a bidirectional control bus.

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