HDMI interface expansion circuit and display device

Abstract

The utility model discloses an HDMI interface expansion circuit and a display device. The HDMI interface expansion circuit comprises a master control module, a signal gating module, an HDMI signal input module and an SDI signal conversion module. The HDMI signal input module is respectively connected with the signal gating module and the main control module; the SDI signal conversion module is respectively connected with the signal gating module and the main control module; the output end of the signal gating module is connected with the video display end, and the main control module is connected with the communication end of the signal gating module; and the main control module is used for outputting a first write-in switching control signal to control the signal gating module to switch the input channel when detecting that the HDMI signal input module is connected, or outputting a second write-in switching control signal to control the signal gating module to switch the input channel when detecting that the SDI signal conversion module is connected. According to the technical scheme, the input of the HDMI signal and the SDI signal can be supported, and the compatibility of the electronic equipment is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to electronic circuit technical field especially relates to a HDMI interface extension circuit and display device. BACKGROUND

[0002] The traditional display scheme of the LED (Light Emitting Diode, light emitting diode) video processor currently generally only contains 1-2 DP, DVI signal interface and HDMI and SDI two optional signal source interface. Therefore, the traditional technical scheme generally makes a choice between the number of HDMI and SDI interface, and cannot realize the problem of HDMI and SDI interface video signal source two optional. Limit the practical application value of LED video processor. INVENTION CONTENT

[0003] The utility model provides a HDMI interface extension circuit and display device to support the input of two kinds of signals of HDMI signal and SDI signal, improve the compatibility of electronic equipment.

[0004] According to an aspect of the utility model, a kind of HDMI interface extension circuit is provided, comprising: main control module, signal gating module, HDMI signal input module and SDI signal conversion module;

[0005] The HDMI signal input module is connected with the first input end of the signal gating module, the main control module respectively, and the HDMI signal input module is used to input standard HDMI signal;

[0006] The SDI signal conversion module is connected with the second input end of the signal gating module, the main control module respectively, and the SDI signal conversion module is used to convert the input SDI signal into HDMI signal;

[0007] The output end of the signal gating module is connected with video display end, and the communication end of the signal gating module is connected with the main control module;

[0008] The main control module is used to output first write switching control signal to control the signal gating module switching input channel when detecting the HDMI signal input module connection, or also used to output second write switching control signal to control the signal gating module switching input channel when detecting the SDI signal conversion module connection.

[0009] Optionally, the HDMI signal input module includes HDMI signal input interface and HDMI signal configuration circuit;

[0010] The HDMI signal input interface is connected with an HDMI signal input source and the HDMI signal configuration circuit respectively, and the HDMI signal configuration circuit is connected with the first input end of the signal gating module and the first detection end of the master control module respectively.

[0011] Optionally, the HDMI signal configuration circuit comprises an HDMI signal configuration chip, the first end to the thirteenth end of the HDMI signal configuration chip are connected with the signal gating module, the thirteenth end of the HDMI signal configuration chip is further connected with the first detection end of the master control module, the fourteenth end of the HDMI signal configuration chip is connected with the first power supply, and the fifteenth end to the twenty-third end of the HDMI signal configuration chip are grounded.

[0012] Optionally, the SDI signal conversion module comprises an SDI signal input interface and an SDI signal conversion circuit.

[0013] The SDI signal input interface is connected with an SDI signal input source and the SDI signal conversion circuit respectively, and the SDI signal conversion circuit is connected with the second input end of the signal gating module and the second detection end of the master control module respectively.

[0014] Optionally, the SDI signal conversion circuit comprises an SDI signal conversion chip.

[0015] The first end to the twelfth end of the SDI signal conversion chip are connected with the signal gating module, the twelfth end of the SDI signal conversion chip is further connected with the second detection end of the master control module, the thirteenth end of the SDI signal conversion chip is connected with the first power supply, and the fourteenth end to the twenty-second end of the SDI signal conversion chip are grounded.

[0016] Optionally, the HDMI interface expansion circuit further comprises a first protection module and a second protection module.

[0017] The first protection module is connected between the HDMI signal input module and the signal gating module, and the second protection module is connected between the SDI signal conversion module and the signal gating module.

[0018] Optionally, the first protection module comprises a first resistor, a second resistor, a third resistor and a fourth resistor.

[0019] The first end of the first resistor is connected with the eleventh end of the HDMI signal configuration chip, the first end of the second resistor is connected with the twelfth end of the HDMI signal configuration chip, the second end of the first resistor is connected with the first end of the third resistor and the signal gating module respectively, the second end of the second resistor is connected with the first end of the fourth resistor and the signal gating module respectively, and the second end of the third resistor and the second end of the fourth resistor are connected with the fourteenth end of the HDMI signal configuration chip.

[0020] The second protection module comprises a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor.

[0021] The first end of the fifth resistor is connected with the tenth end of the SDI signal conversion chip, the first end of the sixth resistor is connected with the eleventh end of the SDI signal conversion chip, the second end of the fifth resistor is connected with the first end of the seventh resistor and the signal gating module respectively, the second end of the sixth resistor is connected with the first end of the eighth resistor and the signal gating module respectively, and the second end of the seventh resistor and the second end of the eighth resistor are connected with the thirteenth end of the SDI signal conversion chip.

[0022] Optionally, the signal gating module comprises an ASW3642 chip.

[0023] Optionally, the main control module outputs a first write switching control signal through an I2C bus to control the signal gating module, or outputs a second write switching control signal to control the signal gating module.

[0024] According to another aspect of the present application, a display device is provided, comprising a video display end and the HDMI interface expansion circuit in any of the above embodiments, and the video display end is connected with the HDMI interface expansion circuit.

[0025] The technical scheme of the embodiment of the utility model discloses a master control module, signal gate module, HDMI signal input module and SDI signal conversion module are set up, the HDMI signal input module is transmitted to the first input of signal gate module with the input standard HDMI signal, and the SDI signal conversion module is transmitted to the second input of signal gate module after converting the input SDI signal into HDMI signal.

[0026] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the utility model, nor is it used to limit the scope of the utility model. Other features of the utility model will become readily apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the drawings needed in the embodiment description will be briefly introduced below, obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creative labor.

[0028] Figure 1 The structural diagram of the HDMI interface expansion circuit provided according to the embodiment of the utility model is shown in the figure;

[0029] Figure 2 The structural diagram of the HDMI signal input module provided according to the embodiment of the utility model is shown in the figure;

[0030] Figure 3 The structural diagram of the SDI signal conversion module provided according to the embodiment of the utility model is shown in the figure;

[0031] Figure 4 The structural diagram of another HDMI interface expansion circuit provided according to the embodiment of the utility model is shown in the figure. DETAILED DESCRIPTION

[0032] In order to make the person skilled in the art better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0033] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and their variants are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] Figure 1 A structural schematic diagram of an HDMI interface expansion circuit according to an embodiment of the present application is shown in Figure 1 The HDMI interface expansion circuit includes a master control module 10, a signal gating module 20, an HDMI signal input module 30 and an SDI signal conversion module 40. The HDMI signal input module 30 is connected to the first input end of the signal gating module 20 and the master control module 10, and is used to input a standard HDMI signal. The SDI signal conversion module 40 is connected to the second input end of the signal gating module 20 and the master control module 10, and is used to convert the input SDI signal into an HDMI signal. The output end of the signal gating module 30 is connected to a video signal end VD, and the communication end of the signal gating module 20 is connected to the master control module 10. The master control module 10 is used to output a first write switching control signal to control the signal gating module 20 to switch the input channel when it is detected that the HDMI signal input module 30 is connected, and is also used to output a second write switching control signal to control the signal gating module 20 to switch the input channel when it is detected that the SDI signal conversion module 40 is connected.

[0035] The main control module 10 can include a single-chip microcomputer or a TV chip. It can be understood that when the main control module 10 includes a TV chip, the TV chip can be integrated in the video display device to improve the integration of the video display device, for example, the video display device can be a television. The main control module 10 can include a first detection end and a second detection end. Exemplarily, the HDMI signal input module 30 is connected with the first detection end of the main control module 10, when the HDMI signal input module 30 is connected with an external device, the first detection end of the main control module 10 inputs high level to indicate that the HDMI signal input module is in an input state; the SDI signal conversion module 40 is connected with the second detection end of the main control module 10, when the SDI signal conversion module 40 is connected with an external device, the second detection end of the main control module 10 inputs high level to indicate that the SDI signal conversion module 40 is in an input state.

[0036] Specifically, the main control module 10 detects the state of the first detection end and the second detection end to control the signal gating module 20. When the main control module 10 detects that the first detection end is high level, a first write switching control signal is output to control the signal gating module 20 to switch to input by the HDMI signal input module 30, and the data input by the HDMI signal input module 30 is output through the output end. Exemplarily, the signal gating module 20 switches to the register of HDMI0 input channel 1. Wherein, the register of HDMI0 input channel 1 can be specifically understood as the register related to the input of the HDMI signal input module 30; when the main control module 10 detects that the second detection end is high level, a second write switching control signal is output to control the signal gating module 20 to switch to input by the SDI signal conversion module 40, and the data input by the SDI signal conversion module 40 is output through the output end. Exemplarily, the signal gating module 20 switches to the register of HDMI1 input channel 2. Wherein, the register of HDMI1 input channel 2 can be specifically understood as the register related to the input of the SDI signal conversion module 40.

[0037] The technical scheme of the embodiment of the utility model discloses, through setting up main control module, signal gate module, HDMI signal input module and SDI signal conversion module, the HDMI signal input module transmits the input standard HDMI signal to the first input end of signal gate module, and the SDI signal conversion module converts the input SDI signal into HDMI signal and then transmits to the second input end of signal gate module. When the main control module detects that the HDMI signal input module or the SDI signal conversion module has external equipment connection input respectively, the main control module outputs corresponding write switch control signal to signal gate module, and then signal gate module responds to the write switch control signal of control module and exports the signal of first input end or second input end through output end. In this way, the present scheme can support the input of two kinds of signals of HDMI signal and SDI signal, so as to improve the compatibility, flexibility and adaptability of electronic equipment, and meet the demand of users for diversified circuit functions.

[0038] Figure 2 For the structure diagram of the HDMI signal input module provided by the embodiment of the utility model, refer to Figure 2 On the basis of the above embodiment, optionally, the HDMI signal input module 30 includes an HDMI signal input interface 31 and an HDMI signal configuration circuit 32; the HDMI signal input interface 31 is connected to the HDMI signal input source HDMI-1 and the HDMI signal configuration circuit 32 respectively, and the HDMI signal configuration circuit 32 is connected to the first input end of the signal gate module 20 and the first detection end of the main control module 10 respectively.

[0039] Among them, the HDMI signal input interface 31 can be specifically understood as a physical interface, which is used for connecting external equipment (such as computer, video camera, etc.), receiving transmitted HDMI signal, for example, the HDMI signal includes high-quality video and audio signal. The HDMI signal configuration circuit 32 is used for processing and configuring the input standard HDMI signal, including signal decoding, format conversion and timing adjustment, etc., to ensure that the signal can be correctly transmitted to the signal gate module 20 and the main control module 10. By setting the HDMI signal input interface and the HDMI signal configuration circuit, it can be ensured that the standard HDMI signal can be stably received and processed.

[0040] Continue to refer to Figure 2 Optionally, the HDMI signal configuration circuit 32 includes an HDMI signal configuration chip U1, the first end to the thirteenth end of the HDMI signal configuration chip U1 is connected with the signal gate module 20, the thirteenth end of the HDMI signal configuration chip U1 is also connected with the first detection end of the main control module 10, the fourteenth end of the HDMI signal configuration chip U1 is connected with the first power supply VCC, and the fifteenth end to the twenty-third end of the HDMI signal configuration chip U1 is grounded.

[0041] The first end HDMI0-RX2P, the second end HDMI0-RX2N, the third end HDMI0-RX1P, the fourth end HDMI0-RX1N, the fifth end HDMI0-RX0P, the sixth end HDMI0-RX0N of the HDMI signal configuration chip U1 are used for transmitting data signals, the seventh end HDMI0-CLKP and the eighth end HDMI0-CLKN are used for transmitting clock signals, the ninth end CEC0 is used for control communication between devices, the tenth end HDMI0-ARC is a reserved pin, the eleventh end HDMI0-SCL and the twelfth end HDMI0-SDA are used for I2C communication, and the thirteenth pin HDMI0-HPD is a detection pin used for detecting a connection state and confirming whether an external device is connected.

[0042] It can be understood that the signal gating module 20 has a plurality of input ends, for example, a first input end and a second input end, and any input end can exemplarily include a plurality of pins. Exemplarily, the plurality of pins of the first input end are in a one-to-one corresponding connection relationship with the functional pins of the HDMI signal configuration chip U1. The thirteenth pin HDMI0-HPD of the HDMI signal configuration chip U1 is also in a connection relationship with the first detection end of the main control module 10.

[0043] Figure 3 A structural schematic diagram of the SDI signal conversion module according to the embodiment of the utility model is shown in Figure 3 On the basis of the above-mentioned embodiments, optionally, the SDI signal conversion module 40 includes an SDI signal input interface 41 and an SDI signal conversion circuit 42; the SDI signal input interface 41 is respectively connected with an SDI signal input source SDI-1 and the SDI signal conversion circuit 42, and the SDI signal conversion circuit 42 is respectively connected with the second input end of the signal gating module 20 and the second detection end of the main control module 10.

[0044] The SDI signal input interface 41 is used for connecting an SDI signal source (such as a camera, a video player, etc.), receiving and transmitting an SDI signal. The SDI signal conversion circuit 42 is used for decoding, format converting and signal processing the received SDI signal. The SDI signal can be converted into an HDMI signal.

[0045] Continuing to refer to Figure 3 Optionally, the SDI signal conversion circuit 42 includes an SDI signal conversion chip U2; the first end to the twelfth end of the SDI signal conversion chip U2 are connected with the signal gating module 20, the twelfth end of the SDI signal conversion chip U2 is also connected with the second detection end of the main control module 10, the thirteenth end of the SDI signal conversion chip U2 is connected with a first power supply VCC, and the fourteenth end to the twenty-second end of the SDI signal conversion chip U2 are grounded.

[0046] In the embodiment, the circuit structure of the SDI signal conversion chip U2 is the same as that of the HDMI signal configuration chip U1, and the first end HDMI1-RX2P, the second end HDMI1-RX2N, the third end HDMI1-RX1P, the fourth end HDMI1-RX1N, the fifth end HDMI1-RX0P, the sixth end HDMI1-RX0N of the SDI signal conversion chip U2 are used for transmitting data signals, the seventh end HDMI1-CLKP and the eighth end HDMI1-CLKN are used for transmitting clock signals, the ninth end CEC1 is used for control communication between devices, the tenth end HDMI1-SCL and the eleventh end HDMI1-SDA are used for I2C communication, and the twelfth pin HDMI1-HPD is a detection pin used for detecting a connection state and confirming whether an external device is connected. In other embodiments, the circuit structure of the SDI signal conversion chip U2 can also adopt other circuit structures, which are not limited in the embodiment.

[0047] It can be understood that the plurality of pins of the second input end are in one-to-one corresponding connection with the functional pins of the SDI signal conversion chip U2. The twelfth pin HDMI0-HPD of the SDI signal conversion chip U2 is also in connection with the second detection end of the main control module 10.

[0048] Figure 4 FIG. 2 is a structural schematic diagram of another HDMI interface expansion circuit according to an embodiment of the present application, which is similar to FIG. 1, and the same parts are not described herein. Figure 4 On the basis of the above embodiments, optionally, the HDMI interface expansion circuit further comprises a first protection module 50 and a second protection module 60, the first protection module 50 is connected between the HDMI signal input module 30 and the signal gating module 20, and the second protection module 60 is connected between the SDI signal conversion module 40 and the signal gating module 20.

[0049] The first protection module 50 and the second protection module 60 are both used for electrical overstress protection (EOS) to protect electronic devices and circuits from potential damage such as electrical overvoltage, overcurrent and electrostatic discharge.

[0050] Continuing to refer to FIG. 2, Figure 4Optionally, the first protection module 50 comprises a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4; a first end of the first resistor R1 is connected with an eleventh end HDMI0-SCL of the HDMI signal configuration chip U1, a first end of the second resistor R2 is connected with a twelfth end HDMI0-SDA of the HDMI signal configuration chip U1, a second end of the first resistor R1 is connected with a first end of the third resistor R3 and the signal gating module 20 respectively, a second end of the second resistor R2 is connected with a first end of the fourth resistor R4 and the signal gating module 20 respectively, and a second end of the third resistor R3 and a second end of the fourth resistor R4 are both connected with a fourteenth end of the HDMI signal configuration chip U1.

[0051] The second end of the third resistor R3 and the second end of the fourth resistor R4 input a voltage of HDMI0-5V. The first resistor R1 and the second resistor R2 are both pull-up resistors, and the third resistor R3 and the fourth resistor R4 are used to improve the EOS protection capability.

[0052] Specifically, when the HDMI signal configuration chip U1 is connected with the signal gating module 20, the third resistor R3 and the fourth resistor R4 can limit the current passing through the signal line, thereby reducing the risk of overcurrent. Thus, the impact of electrostatic discharge or transient overvoltage on the circuit is reduced.

[0053] The second protection module 60 comprises a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8; a first end of the fifth resistor R5 is connected with a tenth end of the SDI signal conversion chip U2, a first end of the sixth resistor R6 is connected with an eleventh end of the SDI signal conversion chip U2, a second end of the fifth resistor R5 is connected with a first end of the seventh resistor R7 and the signal gating module 20 respectively, a second end of the sixth resistor R6 is connected with a first end of the eighth resistor R8 and the signal gating module 20 respectively, and a second end of the seventh resistor R7 and a second end of the eighth resistor R8 are both connected with a thirteenth end of the SDI signal conversion chip U2.

[0054] The second end of the seventh resistor R7 and the second end of the eighth resistor R8 input a voltage of HDMI1-5V. The fifth resistor R5 and the sixth resistor R6 are both pull-up resistors, and the seventh resistor R7 and the eighth resistor R8 are used to improve the EOS protection capability.

[0055] Specifically, when the SDI signal conversion chip U2 is connected with the signal gating module 20, the seventh resistor R7 and the eighth resistor R8 can limit the current passing through the signal line, thereby reducing the risk of overcurrent. Thus, the impact of electrostatic discharge or transient overvoltage on the circuit is reduced.

[0056] It can be understood that the embodiment illustrates the working process of setting the first protection module 50 between the HDMI signal input module 30 and the signal gating module 20, and setting the second protection module 60 between the SDI signal conversion module 40 and the signal gating module 20. Other connection relationships between the HDMI signal input module 30 and the signal gating module 20, and other connection relationships between the SDI signal conversion module 40 and the signal gating module 20 are the same as the connection relationships in any of the above embodiments, and are not specifically shown here.

[0057] With reference to the foregoing Figure 4 Optionally, the signal gating module 20 comprises an ASW3642 chip.

[0058] The ASW3642 chip can be specifically understood as an ASW3642 HDMI SWITCH chip, which can support different working modes and automatically switch according to requirements, and is small in size and easy to integrate.

[0059] With reference to the foregoing Figure 4 Optionally, the main control module 10 outputs a first write switching control signal to control the signal gating module 20 or outputs a second write switching control signal to control the signal gating module 20 through an I2C (Inter-Integrated Circuit, serial communication protocol) bus.

[0060] The I2C is mainly used for short-distance communication between the main control module 10 and peripheral devices. Specifically, the I2C bus comprises two signal lines, a serial data line (SDA) and a serial clock line (SCL).

[0061] Optionally, the utility model embodiment further provides a display device, including video display end and the HDMI interface expansion circuit provided by any of the above embodiments, video display end is connected with the HDMI interface expansion circuit. Therefore, the display device also has the beneficial effects of any of the above embodiments.

[0062] It should be understood that various forms of the flow shown above can be used to reorder, add or delete steps. For example, the steps described in the utility model can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions of the utility model can be achieved, and the present document does not limit this.

[0063] The specific embodiments described above do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An HDMI interface extension circuit, characterized by comprising: The application relates to a signal input module for a video display terminal, which comprises a main control module, a signal gating module, an HDMI signal input module and an SDI signal conversion module. The HDMI signal input module is connected with the first input end of the signal gating module and the main control module, and is used for inputting standard HDMI signals. The SDI signal conversion module is connected with the second input end of the signal gating module and the main control module, and is used for converting inputted SDI signals into HDMI signals. The output end of the signal gating module is connected with a video display terminal, and the communication end of the signal gating module is connected with the main control module. The main control module is used for outputting a first write switching control signal to control the signal gating module to switch the input channel when the HDMI signal input module is connected, or is also used for outputting a second write switching control signal to control the signal gating module to switch the input channel when the SDI signal conversion module is connected. The HDMI signal input module comprises an HDMI signal input interface and an HDMI signal configuration circuit.

2. The HDMI interface extension circuit according to claim 1, wherein, The HDMI signal input interface is connected with an HDMI signal input source and the HDMI signal configuration circuit, and the HDMI signal configuration circuit is connected with the first input end of the signal gating module and the first detection end of the main control module. The HDMI signal configuration circuit comprises an HDMI signal configuration chip, the first end to the thirteenth end of the HDMI signal configuration chip are connected with the signal gating module, the thirteenth end of the HDMI signal configuration chip is also connected with the first detection end of the main control module, the fourteenth end of the HDMI signal configuration chip is connected with a first power supply, and the fifteenth end to the twenty-third end of the HDMI signal configuration chip are grounded.

3. The HDMI interface extension circuit according to claim 2, wherein, The SDI signal conversion module comprises an SDI signal input interface and an SDI signal conversion circuit.

4. The HDMI interface extension circuit according to claim 1, wherein, The SDI signal input interface is connected with an SDI signal input source and the SDI signal conversion circuit, and the SDI signal conversion circuit is connected with the second input end of the signal gating module and the second detection end of the main control module. The SDI signal conversion circuit comprises an SDI signal conversion chip.

5. The HDMI interface extension circuit according to claim 4, characterized in that, The first end to the twelfth end of the SDI signal conversion chip are connected with the signal gating module, the twelfth end of the SDI signal conversion chip is also connected with the second detection end of the main control module, the thirteenth end of the SDI signal conversion chip is connected with a first power supply, and the fourteenth end to the twenty-second end of the SDI signal conversion chip are grounded. The application further relates to a signal input module for a video display terminal, which comprises a first protection module and a second protection module.

6. The HDMI interface extension circuit according to claim 5, characterized by, The first protection module is connected between the HDMI signal input module and the signal gating module, and the second protection module is connected between the SDI signal conversion module and the signal gating module. The first protection module comprises a first resistor, a second resistor, a third resistor and a fourth resistor. ​ 7. The HDMI interface extension circuit according to claim 6, characterized by, ​ The first end of the first resistor is connected with the eleventh end of the HDMI signal configuration chip, the first end of the second resistor is connected with the twelfth end of the HDMI signal configuration chip, the second end of the first resistor is connected with the first end of the third resistor and the signal gating module respectively, the second end of the second resistor is connected with the first end of the fourth resistor and the signal gating module respectively, and the second end of the third resistor and the second end of the fourth resistor are connected with the fourteenth end of the HDMI signal configuration chip. The second protection module comprises a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor. The first end of the fifth resistor is connected with the tenth end of the SDI signal conversion chip, the first end of the sixth resistor is connected with the eleventh end of the SDI signal conversion chip, the second end of the fifth resistor is connected with the first end of the seventh resistor and the signal gating module respectively, the second end of the sixth resistor is connected with the first end of the eighth resistor and the signal gating module respectively, and the second end of the seventh resistor and the second end of the eighth resistor are connected with the thirteenth end of the SDI signal conversion chip.

8. The HDMI interface extension circuit of claim 1, wherein, The signal gating module comprises an ASW3642 chip.

9. The HDMI interface extension circuit according to claim 1, wherein, The main control module outputs a first write switching control signal through an I2C bus to control the signal gating module, or outputs a second write switching control signal to control the signal gating module.

10. A display device, characterized by comprising: The video display end is connected with the HDMI interface expansion circuit.

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