CN116132614A - Signal switching system and method - Google Patents

Abstract

The invention discloses a signal switching system and a signal switching 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 or lower, and cuts off 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 HDMI signal subjected to alternating-current coupling to the target display module, and the HDMI signal meets HDMI2.1 mode specification; when the control signal is in a high level, the direct current bias module is conducted, and at the moment, the direct current bias module and the pull-up resistor of the target display module form direct current bias, so that the target display module receives a direct current coupled HDMI signal and accords with the HDMI2.1 mode specification below, compatibility of a single product to the HDMI2.1 mode and the HDMI2.1 mode below is achieved, and usability and reliability of the single product are improved.

Description

Signal switching system and method

Technical Field

The application relates to the technical field of display, in particular to a signal switching system and a signal switching method.

Background

With the continuous development of technology in the audio and video industry, the requirements of people on video image quality are increasing. The high-definition multimedia interface (High Definition Multimedia Interface, HDMI) video transmission has strong popularity and easiness in wiring, and is an indispensable video signal transmission technology in the field of audio and video transmission. With the update iteration of the HDMI protocol, the transmission rate of HDMI is also higher and higher. HDMI has now evolved to the HDMI2.1 standard. According to the HDMI2.1 standard, when the HDMI2.1 is operated in a Fixed Rate Link (FRL) mode and is switched to a mode below HDMI2.0 and HDMI2.0, the HDMI is operated in a mode of minimizing transmission differential signals (Transition Minimize Differential Signaling, TMDS), and the ground resistance of the HDMI signal transmission path needs to be dc biased with the sink side pull-up resistor. In addition, the TMDS mode usually adopts a DC coupling mode, and according to the HDMI2.1 standard, the HDMI2.1 needs an AC coupling mode. In summary, the FRL-based HDMI2.1 mode cannot be downward compatible with TMDS-based HDMI2.0 and modes below HDMI2.0, resulting in lower product availability and reliability based on a single HDMI mode, which cannot be authenticated by HDMI compatibility test specification (Compliance Test Specification, CTS) when switching HDMI modes.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems existing in the prior art to a certain extent.

Therefore, the embodiment of the invention provides a signal switching system and a signal switching method, which realize compatibility of an HDMI2.1 mode and an HDMI2.1 mode below.

In order to achieve the technical purpose, the technical scheme adopted by the embodiment of the invention comprises the following steps:

in one aspect, an embodiment of the present invention provides a signal switching system, including a main control module and a signal switching circuit;

the main control module is used for generating a control signal according to the working mode of the target display module, wherein the working mode comprises an HDMI2.1 mode and an HDMI2.1 lower mode, the control signal is low level if the working mode is the HDMI2.1 mode, and the control signal is high level if the working mode is the HDMI2.1 lower mode;

the signal switching circuit comprises an alternating current coupling module and a direct current bias module, wherein the input end of the alternating current coupling module is connected with the first output end of the main control module, the first output end of the main control module is used for outputting an HDMI signal, and the output end of the alternating current coupling module is used for outputting the HDMI signal subjected to alternating current coupling to the target display module; the first end of the direct current bias module is connected with the input end of the alternating current coupling module, the second end of the direct current bias module is grounded, the third end of the direct current bias module is connected with the second output end of the main control module, the second output end of the main control module is used for outputting the control signal, if the control signal is in a high level, the direct current bias module is conducted, and if the control signal is in a low level, the direct current bias module is disconnected.

In addition, a signal switching system according to the above embodiment of the present invention may further have the following additional technical features:

further, in the signal switching system of the embodiment of the invention, the main control module comprises a protocol interpretation module and a control signal generation module;

the protocol interpretation module acquires the expansion display identification data of the target display module, obtains the working mode of the target display module according to the expansion display identification data, and if the working mode is HDMI2.1 mode, the control signal generation module generates the control signal and configures the control signal to be low level; and if the working mode is HDMI2.1 or below, the control signal generation module generates the control signal and configures the control signal to be in a high level.

Further, in an embodiment of the present invention, the protocol interpretation module obtains the extended display identification data of the target display module through a bidirectional control bus.

Further, in an embodiment of the present invention, the ac coupling module includes a plurality of groups of first differential lines, where the number of groups of first differential lines is the same as the number of groups of HDMI signals, each group of first differential lines includes a first line and a second line, a first capacitor is disposed on the first line, a second capacitor is disposed on the second line, one end of the first differential line is an input end of the ac coupling module, and the other end of the first differential line is an output end of the ac coupling module.

Further, in an embodiment of the present invention, the first capacitor and the second capacitor are encapsulated with 0201.

Further, in one embodiment of the present invention, the dc offset module includes a plurality of dc offset structures, the number of the dc offset structures is the same as the number of the groups of the first differential lines, each of the dc offset structures includes a group of second differential lines and a switch assembly, each group of second differential lines includes a third line and a fourth line, a first resistor is disposed on the third line, a second resistor is disposed on the fourth line, one end of the second differential line is a first end of the dc offset module, the other end of the second differential line is connected with a first end of the switch assembly, a second end of the switch assembly is a second end of the dc offset module, and a third end of the switch assembly is a third end of the dc offset module;

if the control signal is in a high level, the switch component is conducted;

if the control signal is low, the switching element is turned off.

Further, in an embodiment of the present invention, the switch component is an NMOS tube;

the drain electrode of the NMOS tube is the first end of the switch component, the source electrode of the NMOS tube is the second end of the switch component, and the gate electrode of the NMOS tube is the third end of the switch component.

On the other hand, the embodiment of the invention provides a signal switching method, which is applied to a signal switching system, wherein the signal switching system comprises a main control module and a signal switching circuit, the signal switching circuit comprises an alternating current coupling module and a direct current bias module, and the signal switching method comprises the following steps:

generating a control signal through the main control module according to the working mode of the target display module, wherein the working mode comprises an HDMI2.1 mode and an HDMI2.1 lower mode, the control signal is in a low level if the working mode is the HDMI2.1 mode, and the control signal is in a high level if the working mode is the HDMI2.1 lower mode;

receiving an HDMI signal output by a first output end of the main control module through an input end of the AC coupling module, and receiving the control signal output by a second output end of the main control module through a third end of the DC offset module;

if the control signal is in a high level, the direct current bias module is conducted, and if the control signal is in a low level, the direct current bias module is disconnected, a first end of the direct current bias module is connected with an input end of the alternating current coupling module, and a second end of the direct current bias module is grounded;

and outputting the HDMI signal subjected to alternating current coupling to the target display module through the output end of the alternating current coupling module.

Further, in an embodiment of the present invention, the main control module includes a protocol interpretation module and a control signal generation module;

the generating, by the main control module, a control signal according to the working mode of the target display module includes:

acquiring expansion display identification data of the target display module through the protocol interpretation module, and acquiring a working mode of the target display module according to the expansion display identification data;

if the working mode is HDMI2.1 mode, the control signal generation module generates the control signal and configures the control signal to be low level;

and if the working mode is HDMI2.1 or below, the control signal generation module generates the control signal and configures the control signal to be in a high level.

Further, in an embodiment of the present invention, the protocol interpretation module obtains the extended display identification data of the target display module through a bidirectional control bus.

The invention has the advantages and beneficial effects that:

the signal switching system comprises a main control module and a signal switching circuit, wherein the signal switching circuit comprises an alternating current coupling module and a direct current bias module, a low-level control signal is generated when the working mode of a target display module is HDMI2.1 mode, a high-level control signal is generated when the working mode of the target display module is HDMI2.1 or lower, and the direct current bias module is disconnected when the control signal is low, so that the output end of the alternating current coupling module outputs an alternating current coupled HDMI signal to the target display module, and the standard of the HDMI2.1 mode is met; when the control signal is in a high level, the direct current bias module is conducted, and at the moment, the direct current bias module and the pull-up resistor of the target display module form direct current bias, so that direct current bias voltage is overlapped with an HDMI signal which is output by the output end of the alternating current coupling module and is subjected to alternating current coupling, the target display module receives the direct current coupling HDMI signal and accords with the standard of the HDMI2.1 mode, compatibility of a single product to the HDMI2.1 mode and the HDMI2.1 mode is achieved, usability and reliability of the single product are improved, and the single product can pass through HDMI CTS authentication when the HDMI mode is switched.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following description is made with reference to the accompanying drawings of the embodiments of the present application or the related technical solutions in the prior art, it should be understood that, in the following description, the drawings are only for convenience and clarity to describe some embodiments in the technical solutions of the present application, and other drawings may be obtained according to these drawings without any inventive effort for those skilled in the art.

FIG. 1 is a schematic diagram of a signal switching system according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a first output end of a main control module according to an embodiment of a signal switching system of the present invention;

FIG. 3 is a schematic diagram of a signal switching circuit according to an embodiment of the present invention;

fig. 4 is a flow chart of an embodiment of a signal switching method according to the present invention.

Reference numerals: 301. an ac coupling module; 302. and a direct current bias module.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application. The step numbers in the following embodiments are set for convenience of illustration only, and the order between the steps is not limited in any way, and the execution order of the steps in the embodiments may be adaptively adjusted according to the understanding of those skilled in the art.

The terms "first," "second," "third," and "fourth" and the like in the description and in the claims and drawings are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may include other steps or elements not listed or inherent to such process, method, article, or apparatus.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

With the continuous development of technology in the audio and video industry, the requirements of people on video image quality are increasing. HDMI video transmission has strong popularity and ease of wiring, and is an indispensable video signal transmission technology in the field of audio and video transmission. With the update iteration of the HDMI protocol, the transmission rate of HDMI is also higher and higher. HDMI has now evolved to the HDMI2.1 standard. According to the HDMI2.1 standard, HDMI2.1 works in FRL mode, and when switching to HDMI2.0 and modes below HDMI2.0, HDMI works in TMDS mode, and the ground resistance of HDMI signal transmission path needs to form a DC bias with sink end pull-up resistor. In addition, the TMDS mode usually adopts a DC coupling mode, and according to the HDMI2.1 standard, the HDMI2.1 needs an AC coupling mode. In summary, the FRL-based HDMI2.1 mode cannot be downward compatible with TMDS-based HDMI2.0 and modes below HDMI2.0, resulting in lower product availability and reliability based on a single HDMI mode, which cannot pass HDMI CTS authentication when switching HDMI modes. Therefore, the invention provides a signal switching system and a signal switching method, wherein the signal switching system comprises a main control module and a signal switching circuit, the signal switching circuit comprises an alternating current coupling module and a direct current biasing module, a low-level control signal is generated when the working mode of a target display module is HDMI2.1 mode, a high-level control signal is generated when the working mode of the target display module is HDMI2.1 or below, and the direct current biasing module is disconnected when the control signal is low, so that the output end of the alternating current coupling module outputs an alternating current coupled HDMI signal to the target display module, and the standard of the HDMI2.1 mode is met; when the control signal is in a high level, the direct current bias module is conducted, and at the moment, the direct current bias module and the pull-up resistor of the target display module form direct current bias, so that direct current bias voltage is overlapped with an HDMI signal which is output by the output end of the alternating current coupling module and is subjected to alternating current coupling, the target display module receives the direct current coupling HDMI signal and accords with the standard of the HDMI2.1 mode, compatibility of a single product to the HDMI2.1 mode and the HDMI2.1 mode is achieved, usability and reliability of the single product are improved, and the single product can pass through HDMI CTS authentication when the HDMI mode is switched.

A signal switching system and method according to an embodiment of the present invention are described in detail below with reference to the accompanying drawings, and first, a signal switching system according to an embodiment of the present invention is described.

Referring to fig. 1, a signal switching system in an embodiment of the present invention includes a main control module and a signal switching circuit;

the main control module is used for generating a control signal according to the working mode of the target display module, wherein the working mode comprises an HDMI2.1 mode and an HDMI2.1 lower mode, the control signal is low level if the working mode is the HDMI2.1 mode, and the control signal is high level if the working mode is the HDMI2.1 lower mode;

the signal switching circuit comprises an alternating current coupling module 301 and a direct current bias module 302, wherein the input end of the alternating current coupling module 301 is connected with the first output end of the main control module, the first output end of the main control module is used for outputting an HDMI signal, and the output end of the alternating current coupling module 301 is used for outputting the HDMI signal subjected to alternating current coupling to the target display module; the first end of the dc bias module 302 is connected to the input end of the ac coupling module 301, the second end of the dc bias module 302 is grounded, the third end of the dc bias module 302 is connected to the second output end of the main control module, the second output end of the main control module is used for outputting a control signal, if the control signal is at a high level, the dc bias module 302 is turned on, and if the control signal is at a low level, the dc bias module 302 is turned off.

The HDMI signals include audio signals and video signals, and according to a priori knowledge, the HDMI2.1 mode transmits uncompressed audio signals and video signals, and the HDMI2.1 mode can transmit uncompressed audio signals and video signals, and can also realize higher resolution image presentation by transmitting compressed audio signals and video signals.

It can be understood that the main control module can be a single product such as a PC host and a notebook computer.

Referring to fig. 2, in some embodiments, the first output terminal of the main control module outputs four sets of HDMI signals, wherein HDMI0_tx0p_port and HDMI0_tx0n_port output the first set of HDMI signals, HDMI0_tx1p_port and HDMI0_tx1n_port output the second set of HDMI signals, HDMI0_tx2p_port and HDMI0_tx2n_port output the third set of HDMI signals, and HDMI0_tx4p_port and HDMI0_tx4n_port output the fourth set of HDMI signals.

According to a priori knowledge, the HDMI2.1 operates in the FRL mode, and has a higher bandwidth than the TMDS mode below HDMI2.1, so that higher-quality images can be transmitted. The TMDS mode below HDMI2.1 is usually DC coupling mode, and according to HDMI2.1 standard, HDMI2.1 is AC coupling mode. Ac coupling is ac-on, dc-blocking, whereas dc-coupling allows both dc and ac signals to pass. In the embodiment of the invention, when the working mode of the target display module (Sink end) is the HDMI2.1 mode, the main control module (Source end) generates a low-level control signal, so that the direct current bias module 302 of the signal switching circuit is disconnected, the direct current bias module 302 cannot form direct current bias with the pull-up resistor of the target display module, only the alternating current coupling module 301 plays a role at the moment, and HDMI signals sent by the main control module are transmitted to the target display module after being subjected to alternating current coupling through the alternating current coupling module 301, so that HDMI2.1 mode specifications are met; when the working mode of the target display module is HDMI2.1 below, the main control module generates a high-level control signal to enable the direct current bias module 302 of the signal switching circuit to be conducted, the direct current bias module 302 and the pull-up resistor of the target display module form direct current bias, at the moment, after the HDMI signal sent by the main control module is subjected to alternating current coupling through the alternating current coupling module 301, the HDMI signal and the direct current signal formed by the direct current bias are overlapped and transmitted to the target display module, and the HDMI2.1 below mode specification is met. Therefore, compatibility of a single product to the HDMI2.1 mode and the HDMI2.1 mode below is achieved, and availability and reliability of the single product are improved.

As an optional implementation manner, the main control module comprises a protocol interpretation module and a control signal generation module;

the protocol interpretation module acquires the expansion display identification data of the target display module, obtains the working mode of the target display module according to the expansion display identification data, generates a control signal if the working mode is HDMI2.1 mode, and configures the control signal to be low level; if the working mode is HDMI2.1 below, the control signal generation module generates a control signal and configures the control signal to be in a high level.

Wherein the extended display identification data (Extended Display Identification Data, EDID) is 128 bytes in total, which is a standard for display identification data. EDID is stored in DDC memory of the target display module, with product information of the target display module including display functions (e.g., size, resolution, synchronization), color space, and detailed resolution/timing information.

As an alternative implementation manner, the protocol interpretation module obtains the extended display identification data of the target display module through a bidirectional control bus (such as IIC in fig. 1).

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

As an alternative embodiment, the ac coupling module 301 includes a plurality of groups of first differential lines, where the number of groups of first differential lines is the same as that of groups of HDMI signals, each group of first differential lines includes a first line and a second line, a first capacitor is disposed on the first line, a second capacitor is disposed on the second line, one end of the first differential line is an input end of the ac coupling module 301, and the other end of the first differential line is an output end of the ac coupling module 301.

Optionally, referring to fig. 3, in some embodiments, the ac coupling module 301 includes four sets of first differential lines, where a set of first differential lines individually receives HDMI signals output by a set of main control modules, and a first line and a second line in each set of first differential lines are individually connected to one output port of a first output terminal of the main control module. It is understood that, for the first differential line connected to the HDMI0_tx0p_port and HDMI0_tx0n_port, the first capacitor disposed on the first line is C1 in fig. 3, and the second capacitor disposed on the second line is C2 in fig. 3; for the first differential line connected to the HDMI0_tx1p_port and HDMI0_tx1n_port, the first capacitance set on the first line is C3 in fig. 3, the second capacitance set on the second line is C4 in fig. 3, for the first differential line connected to the HDMI0_tx2p_port and HDMI0_tx2n_port, the first capacitance set on the first line is C5 in fig. 3, the second capacitance set on the second line is C6 in fig. 3, for the first differential line connected to the HDMI0_tx3p_port and HDMI0_tx3n_port, the first capacitance set on the first line is C7 in fig. 3, and the second capacitance set on the second line is C8 in fig. 3.

It can be understood that the capacitor has the characteristics of blocking direct current and passing alternating current, referring to fig. 3, after each group of HDMI signals output by the main control module pass through each capacitor of the ac coupling module 301, an HDMI signal that does not include a direct current signal is obtained at the output end of the ac coupling module 301, that is, the output end of the ac coupling module 301 outputs the HDMI signal that is subjected to ac coupling.

As an alternative embodiment, the first capacitor and said second capacitor are encapsulated with 0201.

According to the embodiment of the invention, the first capacitor and the second capacitor are packaged by 0201, so that ESR (equivalent series resistance) and ESL (equivalent series inductance) of the capacitor are reduced, and impedance change on the first differential line is reduced.

As an alternative implementation manner, the dc offset module 302 includes a plurality of dc offset structures, the number of the dc offset structures is the same as the number of the groups of the first differential lines, each dc offset structure includes a group of second differential lines and a switch component, each group of second differential lines includes a third line and a fourth line, a first resistor is disposed on the third line, a second resistor is disposed on the fourth line, one end of the second differential line is a first end of the dc offset module 302, the other end of the second differential line is connected with a first end of the switch component, a second end of the switch component is a second end of the dc offset module 302, and a third end of the switch component is a third end of the dc offset module 302;

if the control signal is in a high level, the switch component is conducted;

if the control signal is low, the switching element is turned off.

Optionally, referring to fig. 3, in some embodiments, the dc offset module 302 includes four dc offset structures, and a set of second differential lines is individually connected to a set of first differential lines, wherein 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 line connected to the first differential line receiving HDMI signals of HDMI0_tx0p_port and HDMI0_tx0n_port, the first resistance set on the third line is R8 in fig. 3, and the second resistance set on the fourth line is R7 in fig. 3; for the second differential line connected to the first differential line receiving HDMI signals of HDMI0_tx1p_port and HDMI0_tx1n_port, the first resistance set on the third line is R6 in fig. 3, and the second resistance set on the fourth line is R5 in fig. 3; for the second differential line connected to the first differential line receiving HDMI signals of HDMI0_tx2p_port and HDMI0_tx2n_port, the first resistance set on the third line is R4 in fig. 3, and the second resistance set on the fourth line is R3 in fig. 3; for the second differential line connected to the first differential line receiving HDMI signals of HDMI0_tx3p_port and HDMI0_tx3n_port, the first resistance set on the third line is R2 in fig. 3, and the second resistance set on the fourth line is R1 in fig. 3.

As an alternative embodiment, the switch component is an NMOS tube;

the drain electrode of the NMOS tube is the first end of the switch component, the source electrode of the NMOS tube is the second end of the switch component, and the grid electrode of the NMOS tube is the third end of the switch component.

It can be understood that when the control signal is at a high level, all NMOS transistors (e.g., Q1-Q4 in fig. 3) are turned on, and at this time, the pull-up resistor of the target display module and the resistor in the dc bias module 302 form a voltage division circuit (dc bias), which accords with the mode specification below HDMI 2.1; when the control signal is at a low level, all NMOS tubes are not conducted, at this time, the pull-up resistor of the target display module cannot form a voltage dividing circuit (direct current bias) with the resistor in the direct current bias module 302, and the HDMI signal sent by the main control module is transmitted to the target display module after being subjected to alternating current coupling through the alternating current coupling module 301, so that the HDMI2.1 mode specification is met.

Optionally, in some embodiments, the first resistor and the second resistor are equal to each other and are 499 Ω, the pull-up resistor of the target display module is 50Ω, and the dc voltage value of the dc bias formed by the dc bias module 302 and the pull-up resistor of the target display module is 3.3×499/(499+50) =3v.

In summary, in the signal switching system according to the embodiment of the present invention, the main control module generates the low-level control signal when the operation mode of the target display module is the HDMI2.1 mode, generates the high-level control signal when the operation mode of the target display module is the HDMI2.1 or lower, and disconnects the dc offset module 302 when the control signal is the low level, so that the output end of the ac coupling module 301 outputs the ac-coupled HDMI signal to the target display module, which accords with the specification of the HDMI2.1 mode; when the control signal is in a high level, the direct current bias module 302 is conducted, at this time, the direct current bias module 302 and a pull-up resistor of the target display module form direct current bias, so that direct current bias voltage is overlapped with an HDMI signal which is output by an output end of the alternating current coupling module 301 and is subjected to alternating current coupling, the target display module receives the direct current coupling HDMI signal and accords with the specification of the HDMI2.1 mode, compatibility of a single product to the HDMI2.1 mode and the HDMI2.1 mode is achieved, usability and reliability of the single product are improved, and the single product can pass through the HDMI authentication when the HDMI mode is switched.

Next, referring to fig. 4, an embodiment of the present invention provides a signal switching method, which is applied to a signal switching system, where 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, and the signal switching method includes:

s410, generating a control signal through a main control module according to the working mode of the target display module;

the operation mode includes an HDMI2.1 mode and an HDMI2.1 or lower mode, and the control signal is low if the operation mode is the HDMI2.1 mode, and is high if the operation mode is the HDMI2.1 or lower mode.

Optionally, in some embodiments, the main control module includes a protocol interpretation module and a control signal generation module, and step S410 may be further divided into the following steps S411 to S413:

step S411, acquiring expansion display identification data of the target display module through the protocol interpretation module, and acquiring a working mode of the target display module according to the expansion display identification data;

the Extended Display Identification Data (EDID) is a standard for display identification data, and is 128 bytes in total. EDID is stored in DDC memory of the target display module, with product information of the target display module including display functions (e.g., size, resolution, synchronization), color space, and detailed resolution/timing information. It can be understood that after the protocol interpretation module obtains the extended display identification data of the target display module, the working mode of the target display module can be identified as the HDMI2.1 mode or below according to the display identification data.

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

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

Step S412, if the working mode is HDMI2.1 mode, the control signal generating module generates a control signal and configures the control signal to be low level;

in step S413, if the operation mode is HDMI2.1 or below, the control signal generating module generates the control signal and configures the control signal to be at a high level.

S420, receiving an HDMI signal output by a first output end of a main control module through an input end of an alternating current coupling module, and receiving a control signal output by a second output end of the main control module through a third end of a direct current bias module;

the HDMI signals include audio signals and video signals, and according to a priori knowledge, the HDMI2.1 mode transmits uncompressed audio signals and video signals, and the HDMI2.1 mode can transmit uncompressed audio signals and video signals, and can also realize higher resolution image presentation by transmitting compressed audio signals and video signals.

S430, if the control signal is at a high level, the direct current bias module is turned on, and if the control signal is at a low level, the direct current bias module is turned off;

the first end of the direct current bias module is connected with the input end of the alternating current coupling module, and the second end of the direct current bias module is grounded.

S440, outputting the HDMI signal subjected to alternating current coupling to the target display module through the output end of the alternating current coupling module.

According to a priori knowledge, the HDMI2.1 operates in the FRL mode, and has a higher bandwidth than the TMDS mode below HDMI2.1, so that higher-quality images can be transmitted. The TMDS mode below HDMI2.1 is usually DC coupling mode, and according to HDMI2.1 standard, HDMI2.1 is AC coupling mode. Ac coupling is ac-on, dc-blocking, whereas dc-coupling allows both dc and ac signals to pass. In the embodiment of the invention, when the working mode of the target display module is HDMI2.1 mode, the main control module generates a low-level control signal, so that the direct current bias module of the signal switching circuit is disconnected, the direct current bias module cannot form direct current bias with the pull-up resistor of the target display module, only the alternating current coupling module plays a role at the moment, and the HDMI signal sent by the main control module is transmitted to the target display module after being subjected to alternating current coupling by the alternating current coupling module, so that the HDMI2.1 mode specification is met; when the working mode of the target display module is HDMI2.1 below, the main control module generates a high-level control signal to enable the direct current bias module of the signal switching circuit to be conducted, the direct current bias module and the pull-up resistor of the target display module form direct current bias, at the moment, after the HDMI signal sent by the main control module is subjected to alternating current coupling through the alternating current coupling module, the HDMI signal and the direct current signal formed by the direct current bias are overlapped and transmitted to the target display module, and the HDMI signal meets the mode specification below HDMI 2.1. Therefore, compatibility of a single product to the HDMI2.1 mode and the HDMI2.1 mode below is achieved, and availability and reliability of the single product are improved.

The content in the method embodiment is applicable to the system embodiment, the functions specifically realized by the system embodiment are the same as those of the method embodiment, and the achieved beneficial effects are the same as those of the method embodiment.

In some alternative embodiments, the functions/acts noted in the block diagrams may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example in order to provide a more thorough 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 in which sub-operations described as part of a larger operation are performed independently.

Furthermore, while the present application is described in the context of functional modules, it should be appreciated that, unless otherwise indicated, one or more of the functions and/or features may be integrated in a single physical device and/or software module or one or more of the functions and/or features may be implemented in separate physical devices or software modules. It will also be appreciated that a detailed discussion of the actual implementation of each module is not necessary to an understanding of the present application. Rather, the actual implementation of the various functional modules in the apparatus disclosed herein will be apparent to those skilled in the art from consideration of their attributes, functions and internal relationships. Thus, those of ordinary skill in the art will be able to implement the present application as set forth in the claims without undue experimentation. It is also to be understood that the specific concepts disclosed are merely illustrative and are not intended to be limiting upon the scope of the application, which is to be defined by the appended claims and their full scope of equivalents.

It is to be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable program execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

In the foregoing description of the present specification, descriptions of the terms "one embodiment/example", "another embodiment/example", "certain embodiments/examples", and the like, are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

While the preferred embodiment of the present invention has been described in detail, the present invention is not limited to the embodiments described above, and various equivalent modifications and substitutions can be made by those skilled in the art without departing from the spirit of the present invention, and these equivalent modifications and substitutions are intended to be included in the scope of the present invention as defined in the appended claims.

Claims (10)

1. The signal switching system is characterized by comprising a main control module and a signal switching circuit;

the main control module is used for generating a control signal according to the working mode of the target display module, wherein the working mode comprises an HDMI2.1 mode and an HDMI2.1 lower mode, the control signal is low level if the working mode is the HDMI2.1 mode, and the control signal is high level if the working mode is the HDMI2.1 lower mode;

the signal switching circuit comprises an alternating current coupling module and a direct current bias module, wherein the input end of the alternating current coupling module is connected with the first output end of the main control module, the first output end of the main control module is used for outputting an HDMI signal, and the output end of the alternating current coupling module is used for outputting the HDMI signal subjected to alternating current coupling to the target display module; the first end of the direct current bias module is connected with the input end of the alternating current coupling module, the second end of the direct current bias module is grounded, the third end of the direct current bias module is connected with the second output end of the main control module, the second output end of the main control module is used for outputting the control signal, if the control signal is in a high level, the direct current bias module is conducted, and if the control signal is in a low level, the direct current bias module is disconnected.

2. The signal switching system according to claim 1, wherein the main control module comprises a protocol interpretation module and a control signal generation module;

the protocol interpretation module acquires the expansion display identification data of the target display module, obtains the working mode of the target display module according to the expansion display identification data, and if the working mode is HDMI2.1 mode, the control signal generation module generates the control signal and configures the control signal to be low level; and if the working mode is HDMI2.1 or below, the control signal generation module generates the control signal and configures the control signal to be in a high level.

3. The signal switching system according to claim 2, wherein the protocol interpretation module obtains the extended display identification data of the target display module via a bi-directional control bus.

4. The signal switching system according to claim 1, wherein the ac coupling module includes a plurality of groups of first differential lines, the groups of first differential lines are the same as the groups of HDMI signals, each group of first differential lines includes a first line and a second line, a first capacitor is disposed on the first line, a second capacitor is disposed on the second line, one end of the first differential line is an input end of the ac coupling module, and the other end of the first differential line is an output end of the ac coupling module.

5. The signal switching system of claim 4, wherein the first capacitor and the second capacitor are encapsulated with 0201.

6. The signal switching system according to claim 4, wherein the dc offset module includes a plurality of dc offset structures, the number of the dc offset structures is the same as the number of the groups of the first differential lines, each of the dc offset structures includes a group of second differential lines and a switch assembly, each group of the second differential lines includes a third line and a fourth line, the third line is provided with a first resistor, the fourth line is provided with a second resistor, one end of the second differential line is a first end of the dc offset module, the other end of the second differential line is connected with the first end of the switch assembly, the second end of the switch assembly is a second end of the dc offset module, and the third end of the switch assembly is a third end of the dc offset module;

if the control signal is in a high level, the switch component is conducted;

if the control signal is low, the switching element is turned off.

7. The signal switching system of claim 6, wherein the switching element is an NMOS tube;

the drain electrode of the NMOS tube is the first end of the switch component, the source electrode of the NMOS tube is the second end of the switch component, and the gate electrode of the NMOS tube is the third end of the switch component.

8. The signal switching method is characterized by being applied to a signal switching system, wherein the signal switching system comprises a main control module and a signal switching circuit, the signal switching circuit comprises an alternating current coupling module and a direct current biasing module, and the signal switching method comprises the following steps:

generating a control signal through the main control module according to the working mode of the target display module, wherein the working mode comprises an HDMI2.1 mode and an HDMI2.1 lower mode, the control signal is in a low level if the working mode is the HDMI2.1 mode, and the control signal is in a high level if the working mode is the HDMI2.1 lower mode;

receiving an HDMI signal output by a first output end of the main control module through an input end of the AC coupling module, and receiving the control signal output by a second output end of the main control module through a third end of the DC offset module;

if the control signal is in a high level, the direct current bias module is conducted, and if the control signal is in a low level, the direct current bias module is disconnected, a first end of the direct current bias module is connected with an input end of the alternating current coupling module, and a second end of the direct current bias module is grounded;

and outputting the HDMI signal subjected to alternating current coupling to the target display module through the output end of the alternating current coupling module.

9. The signal switching method according to claim 8, wherein the main control module comprises a protocol interpretation module and a control signal generation module;

the generating, by the main control module, a control signal according to the working mode of the target display module includes:

acquiring expansion display identification data of the target display module through the protocol interpretation module, and acquiring a working mode of the target display module according to the expansion display identification data;

if the working mode is HDMI2.1 mode, the control signal generation module generates the control signal and configures the control signal to be low level;

and if the working mode is HDMI2.1 or below, the control signal generation module generates the control signal and configures the control signal to be in a high level.

10. The signal switching method according to claim 9, wherein the protocol interpretation module obtains the extended display identification data of the target display module through a bidirectional control bus.

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