HDMI interface multiplexing circuit and control method thereof

Abstract

The application provides an HDMI interface multiplexing circuit and a control method thereof, wherein the circuit comprises an SOC chip and a switching circuit arranged at each HDMI transmission channel, and the switching circuit comprises: a first HDMI transmission channel signal branch electrically connected with the SOC chip; a MIPI signal branch electrically connected with the SOC chip; a first gating switch having a fixed end electrically connected with an HDMI socket, a first contact end arranged at one end of the first HDMI transmission channel signal branch away from the SOC chip, and a second contact end arranged at one end of the MIPI signal branch away from the SOC chip; and the gating switch is used to realize HDMI signal transmission by connecting the fixed end with the first contact end or to realize MIPI signal transmission by connecting the fixed end with the second contact end under the control of the SOC chip. On the basis of not changing the original HDMI interface circuit, the MIPI signal transmission circuit is newly added, so that the requirements of video data transmission delay, long-distance transmission and expansibility are met, and the purposes of reducing data transmission delay, long-distance data transmission and high expansibility are achieved.

Description

Technical Field

[0001] This invention relates to the field of interface technology, and specifically to an HDMI interface multiplexing circuit and its control method. Background Technology

[0002] Currently, most network cameras on the market compress the sampled video files before transmitting them over the network to a box-type device (edge ​​processor). In this scenario, the transmission latency of network cameras is relatively long. This makes it difficult to cover applications requiring high real-time performance. Take facial recognition access control as an example: the camera monitors faces, and if the face is authorized, the door opens. The image transmission latency of this type of camera directly affects the user experience. For instance, if facial recognition passes but the door only opens after 3 seconds, the customer experience will be very poor.

[0003] Currently, in scenarios requiring low latency, box-type devices offer several solutions:

[0004] Using a flexible flat cable to connect the camera and the box-type device, communicating via a MIPI interface, presents several challenges. Firstly, the socket has a short lifespan due to frequent plugging and unplugging, making it prone to damage. Secondly, the MIPI signal transmitted over a short distance requires the camera and box-type device to be physically close (generally no more than 300mm). In typical field applications, cameras are usually installed in specific, high positions, and the box-type device needs to connect multiple cameras. This connection method significantly limits its application.

[0005] Another possible solution is to reserve an interface (usually a FAKRA interface) on the box-type device for automotive applications to connect such cameras. The disadvantage of this solution is that the panel space of the box-type device is limited, and the need to connect MIPI cameras is not a universal requirement. Most users will not need it, and only a small number of users with high requirements for real-time image data will use this interface. This causes the interface to occupy the space of other functions, affecting the functionality of most users.

[0006] In summary, existing solutions using box-type devices cannot simultaneously meet the latency requirements, transmission distance, and scalability requirements for video data transmission. Summary of the Invention

[0007] In view of this, the present invention provides an HDMI interface multiplexing circuit and its control method to solve the problems of high latency and inability to perform long-distance and low scalability of video data transmission in the prior art.

[0008] In a first aspect, the present invention provides an HDMI interface multiplexing circuit, including a SOC chip and a switching circuit disposed in each HDMI transmission channel. The switching circuit includes: a first HDMI transmission channel signal branch electrically connected to the SOC chip; a MIPI signal branch electrically connected to the SOC chip; and a first gating switch, with a fixed end electrically connected to an HDMI socket, a first contact end disposed at the end of the first HDMI transmission channel signal branch away from the SOC chip, and a second contact end disposed at the end of the MIPI signal branch away from the SOC chip. The gating switch is used, under the control of the SOC chip, to achieve HDMI signal transmission by connecting the fixed end to the first contact end or to achieve MIPI signal transmission by connecting the fixed end to the second contact end.

[0009] Optionally, the MIPI signal branch includes: a voltage source circuit connected to the second contact terminal to provide a 12V voltage; and a signal processing module, one end of which is electrically connected to the voltage source circuit and connected to the second contact terminal, and the other end of which is connected to the SOC chip.

[0010] Optionally, the voltage source circuit includes: a voltage source; an electronically controlled switch, the control terminal of which is electrically connected to the SOC chip for controlling the on / off state of the voltage source; and an inductor filter circuit, one end of which is connected to the voltage source via the electronically controlled switch, and the other end of which is connected to the second contact terminal, wherein the electronically controlled switch and the inductor filter circuit are grounded through a first capacitor.

[0011] Optionally, the inductor filter circuit includes: a first inductor, a second inductor, and a third inductor connected in series, the first inductor being connected to the electronically controlled switch, the third inductor being connected to the second contact terminal; and a first resistor connected in parallel with the second inductor.

[0012] Optionally, the first inductance is greater than the second inductance, and the second inductance is greater than the third inductance.

[0013] Optionally, the signal processing module uses a MAX9296 chip to convert GMSL signals into MIPI signals, wherein the SOC chip is also electrically connected to the signal processing module via an I2C signal line.

[0014] Optionally, a second capacitor is connected between the MAX9296 chip and the second contact terminal.

[0015] Optionally, the switching circuit further includes: a second HDMI transmission channel signal branch line electrically connected to the SOC chip; a second gating switch, with its fixed end electrically connected to the HDMI socket, a first contact end located at the end of the second HDMI transmission channel signal branch line away from the SOC chip, and a second contact end grounded.

[0016] Optionally, the fixed terminal of the first selector switch is grounded through a first grounding branch; the fixed terminal of the second selector switch is grounded through a second grounding branch; and the control terminals of the first and second grounding branches are electrically connected to the SOC chip.

[0017] Optionally, the first grounding branch is the same as the second grounding branch and includes: a second resistor and a switching transistor; the second resistor and the switching transistor are connected in series, and the control terminal of the switching transistor is electrically connected to the SOC chip.

[0018] Optionally, the shielded signal terminal of the HDMI socket is grounded, and the hot-swappable pin of the HDMI socket is connected to the SOC chip.

[0019] Alternatively, the switching circuit structure for different HDMI transmission channels is the same.

[0020] Secondly, the present invention provides a control method for an HDMI interface multiplexing circuit, characterized in that it is applicable to the aforementioned HDMI interface multiplexing circuit, the control method comprising: detecting whether the hot-plug pin of the HDMI socket is valid; if the hot-plug pin is invalid, controlling a first gating switch to be connected to a second contact terminal to achieve MIPI signal transmission; if the hot-plug pin is valid, controlling the first gating switch to be connected to a first contact terminal to achieve HDMI signal transmission.

[0021] Optionally, it further includes: if the hot-plug pin is invalid, controlling the GPIO signal to output a low level and controlling the electronic control switch to close, and connecting the second gating switch to the second contact terminal.

[0022] Optionally, it further includes: if the hot-plug pin is valid, controlling the GPIO signal to output a high level and controlling the electronic switch to open, and connecting the second gating switch to the first contact terminal.

[0023] The technical solutions provided by the embodiments of the present invention can achieve the following technical effects:

[0024] By setting a switching circuit on each transmission channel of the HDMI interface socket in the box-type device, the signal line is selected through the first selection switch and the selection control is performed by the SOC chip, thereby realizing HDMI signal transmission or MIPI signal transmission. Without changing the original HDMI interface circuit, a new MIPI signal transmission circuit is added to meet the requirements of video data transmission latency, long-distance transmission and scalability, so as to reduce data transmission latency, remote data transmission and high scalability.

[0025] By employing the interface multiplexing circuit described in the above embodiments, the validity of hot-plug pins is detected, and the type of interface to be accessed is determined based on the validity of the hot-plug pins. Then, the circuit switches to the corresponding interface circuit for data transmission, achieving adaptive interface recognition without manual control. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a circuit diagram of a switching circuit according to an embodiment of the present invention;

[0028] Figure 2 This is a circuit diagram of a switching circuit according to another embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the line end interface according to an embodiment of the present invention;

[0030] Figure 4 This is a block diagram of an HDMI interface multiplexing circuit according to an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of the HDMI interface pinout according to an embodiment of the present invention;

[0032] Figure 6 This is a flowchart of the control method according to an embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Before introducing the embodiments of the present invention, the technical terms used in the embodiments of the present invention will be explained:

[0035] HDMI: High Definition Multimedia Interface (HDMI) is a fully digital video and audio transmission interface that can transmit uncompressed audio and video signals.

[0036] FD-LINK: Flat panel display link, a high-speed interface launched by TI, with the same application scenarios and functions as GMSL.

[0037] GMSL: Gigabit Multimedia Serial Links, is a high-speed serial interface introduced by Maxim Integrated, suitable for the transmission of audio, video and control signals.

[0038] GPIO: General-purpose input / output, similar in function to P0-P3 of 8051, its pins can be freely used by the user through program control.

[0039] MIPI: Mobile Industry Processor Interface.

[0040] This invention improves upon the original HDMI interface by designing a switching circuit that enables both HDMI and MIPI signal transmission.

[0041] Currently, HDMI is mainly used for monitor connection and testing in practical applications. In actual camera applications, display data is generally transmitted from the network. The technical solution provided in this invention reuses the HDMI interface to achieve the following functions: After inserting an HDMI device, the HDMI interface automatically outputs an HDMI signal for connecting to a monitor. When a GSMEL or FD-LINK camera signal cable is inserted, through software settings, uncompressed real-time data from the camera can be transmitted using GSMEL or FD-LINK, catering to applications with high real-time requirements.

[0042] Specifically, this embodiment of the invention provides an HDMI interface multiplexing circuit, including a SOC chip and a switching circuit configured for each HDMI transmission channel.

[0043] In this embodiment of the invention, an HDMI interface typically includes three TMDS transmission channels for data transmission and one independent TMDS clock channel. In this embodiment, a switching circuit is provided on each transmission channel and the TMDS clock channel to switch between HDMI signal transmission and MIPI signal transmission. The structure of the switching circuit on each channel can be the same or different. In this embodiment, the same circuit structure is preferred to ensure consistency across channels.

[0044] It should be noted that, in this embodiment of the invention, the HDMI interface multiplexing circuit is an improved circuit between the original HDMI interface socket and the SOC chip. That is, a custom FAKRA to HDMI cable can be used, and a unified HDMI socket is employed for connection, enabling the transmission of two different signals. The custom cable has one HDMI interface and four FAKRA interfaces at the other end, specifically a FAKRA coaxial cable, connected to the differential pins of the HDMI TMDS (TMDS or clock signal). The signal pins are connected to the positive terminal of the differential pins, and the shielding layer of the coaxial cable is connected to the negative terminal and the shielded signal pin of the HDMI socket's TMDS or clock signal.

[0045] The switching circuit described in this embodiment of the invention includes: a first HDMI transmission channel signal branch electrically connected to the SOC chip; a MIPI signal branch electrically connected to the SOC chip; and a first gating switch, with its fixed end electrically connected to the HDMI socket, a first contact end disposed at the end of the first HDMI transmission channel signal branch away from the SOC chip, and a second contact end disposed at the end of the MIPI signal branch away from the SOC chip. The gating switch is used, under the control of the SOC chip, to achieve HDMI signal transmission by connecting the fixed end to the first contact end or to achieve MIPI signal transmission by connecting the fixed end to the second contact end.

[0046] In this embodiment of the invention, the first HDMI transmission channel signal branch can refer to the positive signal line of the transmission channel, such as... Figure 1 The TMDS0+ signal line shown, and the MIPI signal branch line, can refer to the line connected to the TMDS0+ connector of the HDMI socket for converting to MIPI signals. When the contact of the first selector switch K1 is connected to the first contact terminal, it indicates that MIPI signal transmission is required; when the contact of the first selector switch K1 is connected to the second contact terminal, it indicates that HDMI signal transmission is required. Figure 1 The electrical control connection between the SOC chip and switch K1 is not shown.

[0047] According to an embodiment of the present invention, by setting a switching circuit on each transmission channel of the HDMI interface socket in the box-type device, the signal line is selected by a first selection switch and the selection control is performed by the SOC chip, thereby realizing HDMI signal transmission or MIPI signal transmission. Without changing the original HDMI interface circuit, a new MIPI signal transmission circuit is added to meet the requirements of video data transmission latency, long-distance transmission and scalability, thereby achieving the purpose of reducing data transmission latency, remote data transmission and high scalability.

[0048] Furthermore, in this embodiment, since the circuits for HDMI signal transmission and MIPI signal transmission differ, and HDMI has hot-plug pins, the validity of the hot-plug pins identified by the SOC chip can be used to automatically determine which type of cable is being connected and which signal transmission method is required. When an HDMI cable is inserted to connect to an HDMI device, the switching control circuit can recognize that an HDMI device is being inserted because of the HDMI hot-plug identification pins. It then automatically switches the signal through the switching circuit to the HDMI circuit, thus enabling HDMI-related functions.

[0049] As an alternative implementation method, such as Figure 1 As shown in the embodiment of the present invention, the MIPI signal branch includes: a voltage source circuit 10, connected to the second contact terminal, for providing 12V voltage; and a signal processing module 20, one end of which is electrically connected to the voltage source circuit and connected to the second contact terminal, and the other end of which is connected to the SOC chip.

[0050] In this embodiment of the invention, when a GMSL cable is connected, according to the GMSL specification, both power supply and signal transmission must be transmitted through the cable, and the power supply is 12V. If a cable detection circuit is set up, a false detection would output 12V voltage to the HDMI device, causing damage to the HDMI device. The voltage source circuit 10 is used to generate 12V voltage as the voltage required for MIPI signal transmission of the GMSL cable. Furthermore, to avoid affecting the HDMI device, this voltage is only used when using MIPI signal transmission; it is not needed when using HDMI signal transmission.

[0051] The signal processing module uses a MAX9296 chip to convert GMSL signals into MIPI signals. The SOC chip is also electrically connected to the signal processing module via an I2C signal line. A second capacitor C1 is connected between the MAX9296 chip and the second contact terminal.

[0052] Furthermore, such as Figure 2 As shown, the voltage source circuit includes: a voltage source Vdd; an electronically controlled switch K2, the control terminal of which is electrically connected to the SOC chip (not shown in the figure), for controlling the on / off state of the voltage source Vdd; and an inductor filter circuit 101, one end of which is connected to the voltage source Vdd through the electronically controlled switch K2, and the other end of which is connected to the second contact terminal, wherein the electronically controlled switch K2 and the inductor filter circuit 101 are grounded through a first capacitor C4.

[0053] Considering practical application scenarios, switching to GMSL is generally for known and fixed applications, and corresponding processing software is deployed on the SOC chip. Therefore, when switching to GMSL using software control, it is necessary to confirm that a GMSL camera is being used before switching to the GMSL function. This avoids hardware damage and prevents the HDMI device from being burned out due to a 12V input when connected.

[0054] As an optional implementation, the inductor filter circuit of this embodiment includes: a first inductor L1, a second inductor L2, and a third inductor L3 connected in series. The first inductor is connected to the electronically controlled switch, and the third inductor is connected to the second contact terminal; a first resistor R3 is connected in parallel with the second inductor. The first inductance is greater than the second inductance, and the second inductance is greater than the third inductance. The inductance of the first inductor is 100uH, the inductance of the second inductor is 22uH, and the inductance of the third inductor is 560nH.

[0055] The switching circuit of this embodiment further includes: a second HDMI transmission channel signal branch TMDS0-, which is electrically connected to the SOC chip; a second gating switch K3, whose fixed end is electrically connected to the HDMI socket, the first contact end is located at the end of the second HDMI transmission channel signal branch away from the SOC chip, and the second contact end is grounded Vss.

[0056] In this embodiment of the invention, the first selection switch K1, the electronic control switch K2, and the second selection switch K3 are all controlled by the SOC chip (the connection relationship is not shown in the figure) to select the corresponding circuit. The SOC chip can be a JETSON NXSOC, and the specific switching device can be an analog switch, such as a transistor or a MOSFET, or a small relay.

[0057] As an optional implementation, in the HDMI interface multiplexing circuit of this embodiment, the fixed terminal of the first gating switch is grounded through a first grounding branch; the fixed terminal of the second gating switch is grounded through a second grounding branch; the control terminals of the first and second grounding branches are electrically connected to the SOC chip. Specifically, the first and second grounding branches are the same and include: a second resistor (R1 and R2) and a switching transistor (V1 and V2); the second resistor and the switching transistor are connected in series, and the control terminal of the switching transistor is electrically connected to the SOC chip.

[0058] In this embodiment of the invention, the SOC chip controls the grounding of the positive and negative pins of the transmission channel via GPIO signals. The on and off of the switching transistor is controlled according to the specific interface control requirements. For example, in the case of HDMI signal transmission or MIPI signal transmission, the SOC chip controls the switching according to the specific transmission requirements.

[0059] The shielded signal terminal of the HDMI socket is grounded, and the hot-plug pins of the HDMI socket are connected to the SOC chip. The validity of the hot-plug pins is detected by monitoring the SOC chip to determine whether the current transmission requirement is HDMI or MIPI signal transmission.

[0060] Combination Figure 2 The technical solution of this application will be described in detail below:

[0061] When GMSL device access is selected, K2 is off, and VDD 12V is filtered through an inductor and supplied to the pin of switch K1. K1 selects the TMDS+ pin, which is connected to the camera via a cable. Simultaneously, K3 connects TMDS0- to ground, and together with the TMDS0 shield pin, connects to the ground (shield) of the coaxial cable. For the signal, the data signal from the front-end camera is connected to the TMDS0+ pin via a cable, and then through K1 to the left side of the pin at the end of capacitor C1. Since the signal frequency is GHz, it is connected to the MAX9296 via a DC blocking capacitor. The MAX9296 chip converts the GMSL signal into a MIPI signal, which is then connected to the MIPI interface of the SOC chip for data processing.

[0062] When the default or connected device is an HDMI device, K2 is disconnected, K1 and K3 are connected to the lower endpoint, and V1 and V2 are turned on through GPIO to provide a bias level to meet the HDMI signal specification. The HDMI signal is driven by the HDMI controller of JETSON NX SOC, through capacitors C2 and C3, and then through the HDMI socket to the HDMI cable to drive the display to work.

[0063] An interface circuit block diagram provided in an embodiment of the present invention, such as... Figure 3 As shown, the cable ends are FAKRA to HDMI adapters, with the FAKRA ports connecting to the respective transmission channels of the HDMI plug. The HDMI plug is then inserted into the HDMI socket, and the internal circuitry of the socket is as follows. Figure 4 As shown, the HDMI connector uses a switching circuit to switch between GMSL and HDMI interface functions, thereby enabling either MIPI or HDMI signal transmission, and then transmitting the data to the SOC chip. A pin diagram of the HDMI connector is shown below. Figure 5 As shown.

[0064] This invention also provides a control method for an HDMI interface multiplexing circuit, applicable to the HDMI interface multiplexing circuit described in the above embodiments of this invention, such as... Figure 6 As shown, the control method includes:

[0065] Step S601: Check if the hot-swap pins of the HDMI socket are valid. During use, the hot-swap pins can receive valid electrical signals when transmitting HDMI signals; however, when transmitting MIPI signals, the hot-swap pins are not needed and therefore do not have electrical signals. Therefore, by checking the validity of the hot-swap pins, it is possible to quickly determine whether a FAKRA interface or an HDMI interface is connected.

[0066] In step S602, if the hot-swappable pin is invalid, the first gating switch is connected to the second contact terminal to realize MIPI signal transmission.

[0067] Step S603: If the hot-swappable pin is valid, control the first gating switch to connect to the first contact terminal to realize HDMI signal transmission.

[0068] When the hot-swap pin is invalid, it indicates that the FAKRA interface is connected, and the first selector switch K1 is connected to the second contact terminal to realize MIPI signal transmission; when the hot-swap pin is valid, it indicates that the HDMI interface is connected, and the first selector switch K1 is connected to the first contact terminal to realize HDMI signal transmission.

[0069] According to embodiments of the present invention, by employing the interface multiplexing circuit described in the above embodiments, the validity of hot-plug pins is detected, the access interface type is determined based on the validity of the hot-plug pins, and then the corresponding interface circuit is switched to perform data transmission, thereby achieving interface adaptive identification without manual control.

[0070] Optionally, in this embodiment of the invention, if the hot-swap pin is invalid, the GPIO signal is controlled to output a low level, and the electronic switch K3 is controlled to close, with the second gating switch K3 connected to the second contact terminal. This enables all MIPI signal transmission circuits. If the hot-swap pin is valid, the GPIO signal is controlled to output a high level, turning on the switching transistors (V1 and V2), and the electronic switch K2 is controlled to open, with the second gating switch K3 connected to the first contact terminal, thereby enabling all HDMI signal transmission circuits.

[0071] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An HDMI interface multiplexing circuit, characterized in that, Includes a SOC chip and a switching circuit configured for each HDMI transmission channel, the switching circuit comprising: The first HDMI transmission channel signal branch is electrically connected to the SOC chip; The MIPI signal branch is electrically connected to the SOC chip; the MIPI signal is obtained by converting the GMSL signal. The first gating switch has a fixed end electrically connected to the HDMI socket. A first contact end is located at the end of the first HDMI transmission channel signal branch furthest from the SOC chip, and a second contact end is located at the end of the MIPI signal branch furthest from the SOC chip. The gating switch, under the control of the SOC chip, enables HDMI signal transmission by connecting the fixed end to the first contact end or MIPI signal transmission by connecting the fixed end to the second contact end. The HDMI socket is used to connect a custom cable, one end of which has an HDMI interface, and the other end has four FAKRA interfaces.

2. The HDMI interface multiplexing circuit according to claim 1, characterized in that, The MIPI signal branch includes: A voltage source circuit, connected to the second contact terminal, is used to provide 12V voltage; The signal processing module is electrically connected at one end to the voltage source circuit and connected to the second contact terminal, and at the other end to the SOC chip.

3. The HDMI interface multiplexing circuit according to claim 2, characterized in that, The voltage source circuit includes: Voltage source; An electronically controlled switch, with its control terminal electrically connected to the SOC chip, is used to control the on / off state of the voltage source; An inductor filter circuit has one end connected to the voltage source via the electronically controlled switch and the other end connected to the second contact terminal. The electronically controlled switch and the inductor filter circuit are grounded through a first capacitor.

4. The HDMI interface multiplexing circuit according to claim 3, characterized in that, The inductor filter circuit includes: A first inductor, a second inductor, and a third inductor are connected in series, with the first inductor connected to the electronic control switch and the third inductor connected to the second contact terminal. The first resistor is connected in parallel with the second inductor.

5. The HDMI interface multiplexing circuit according to claim 4, characterized in that, The first inductance is greater than the second inductance, and the second inductance is greater than the third inductance.

6. The HDMI interface multiplexing circuit according to claim 2, characterized in that, The signal processing module uses a MAX9296 chip to convert GMSL signals into MIPI signals. The SOC chip is also electrically connected to the signal processing module via an I2C signal line.

7. The HDMI interface multiplexing circuit according to claim 6, characterized in that, A second capacitor is connected between the MAX9296 chip and the second contact terminal.

8. The HDMI interface multiplexing circuit according to claim 1, characterized in that, The switching circuit further includes: The second HDMI transmission channel signal branch is electrically connected to the SOC chip. The second selector switch has a fixed end that is electrically connected to the HDMI socket, a first contact end that is located at the end of the second HDMI transmission channel signal branch that is away from the SOC chip, and a second contact end that is grounded.

9. The HDMI interface multiplexing circuit according to claim 8, characterized in that, The fixed terminal of the first selector switch is grounded through the first grounding branch; The fixed terminal of the second selector switch is grounded through the second grounding branch; The control terminals of the first grounding branch and the second grounding branch are electrically connected to the SOC chip.

10. The HDMI interface multiplexing circuit according to claim 9, characterized in that, The first grounding branch is the same as the second grounding branch and includes: a second resistor and a switching transistor; The second resistor is connected in series with the switching transistor, and the control terminal of the switching transistor is electrically connected to the SOC chip.

11. The HDMI interface multiplexing circuit according to claim 9, characterized in that, The shielded signal terminal of the HDMI socket is grounded, and the hot-swappable pin of the HDMI socket is connected to the SOC chip.

12. The HDMI interface multiplexing circuit according to claim 9, characterized in that, The switching circuit structure for different HDMI transmission channels is the same.

13. A control method for an HDMI interface multiplexing circuit, characterized in that, The control method, applicable to the HDMI interface multiplexing circuit according to any one of claims 1-12, comprises: Check if the hot-plug pins of the HDMI socket are valid; If the hot-swappable pin is invalid, the first gating switch is connected to the second contact terminal to realize MIPI signal transmission; If the hot-swappable pin is active, the first gating switch is connected to the first contact terminal to enable HDMI signal transmission.

14. The control method according to claim 13, characterized in that, Also includes: If the hot-swappable pin is invalid, the GPIO signal is controlled to output a low level, and the electronic control switch is controlled to close, with the second selector switch connected to the second contact terminal.

15. The control method according to claim 13, characterized in that, Also includes: If the hot-swappable pin is active, the GPIO signal is controlled to output a high level, and the electronic control switch is turned off, with the second selector switch connected to the first contact terminal.

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