HDMI protection board circuit, HDMI protection board and device

Abstract

The present invention discloses an HDMI protection board circuit, an HDMI protection board and a device. The HDMI protection board circuit includes: a power protection circuit, multiple common mode inductor modules, a hot plug pull-down circuit, a display data channel impedance matching circuit and a consumer electronics control pull-up circuit; the power protection circuit, the common mode inductor module, the hot plug pull-down circuit, the display data channel impedance matching circuit and the consumer electronics control pull-up circuit are respectively connected between the HDMI male head and the HDMI port; the common mode inductor module is used to filter out the common mode interference on the HDMI differential line. Therefore, the present invention can improve the protection performance of the HDMI interface by filtering out the common mode interference and the fixed frequency interference.

Description

Technical Field

[0001] The present invention relates to the field of multimedia technology, and in particular to an HDMI protection board circuit, an HDMI protection board and a device. Background Art

[0002] With the development of technology, HDMI is a fully digital audio and video transmission interface. The HDMI interface supports the transmission of high-resolution video streams and high-fidelity audio streams, greatly reducing the complexity of wiring. It is widely used in consumer electronic devices such as TVs, players, personal computers, digital audio, etc.

[0003] However, the existing HDMI devices have focused on how to increase the amount of data transmission and ignored the protective measures. Only TVS tubes are added to all HDMI ports to prevent ESD (Electro-Static discharge) problems. In other words, only the influence of static electricity on the data line is protected, and the interference of common-mode signals on differential-mode signals is ignored, which causes interference to the signals on the differential pair, resulting in instability of the HDMI interface and the rear circuits and data instability. It is easy to be interfered by the outside world and cause circuit damage.

[0004] In summary, traditional HDMI devices do not have a complete protection solution. Summary of the invention

[0005] The main purpose of the present invention is to propose an HDMI protection board circuit, an HDMI protection board and a device, aiming to achieve the problem of preventing noise and current backflow at the power input end by filtering out common-mode interference and fixed-frequency interference that occur during data line transmission in the HDMI interface, and at the same time, prevent the problem of CEC, DDC and hot-plug interfaces being unstable and easily mistriggered when there is no signal transmission, thereby improving the protection performance of the HDMI interface.

[0006] To achieve the above object, the present invention provides an HDMI protection board circuit, the HDMI protection board circuit is connected between the HDMI male connector and the HDMI port, and the HDMI protection board circuit includes: a power protection circuit, a plurality of common mode inductor modules, a hot plug pull-down circuit, a display data channel impedance matching circuit and a consumer electronics control pull-up circuit;

[0007] The power protection circuit, the common mode inductor module, the hot plug pull-down circuit, the display data channel impedance matching circuit and the consumer electronics control pull-up circuit are each connected between the HDMI male connector and the HDMI port;

[0008] The power protection circuit is used to eliminate the interference of fixed frequency on the power line and prevent the HDMI port from current backflow;

[0009] The common mode inductor module is used to filter out common mode interference on the HDMI differential line;

[0010] The hot-swap pull-down circuit is used to maintain a stable low-level state and filter out high-frequency noise;

[0011] The consumer electronics control pull-up circuit is used to maintain a stable high level state;

[0012] The display data channel impedance matching circuit is used for impedance matching of the signal line and absorbing the reflected signal.

[0013] Optionally, the power protection circuit is connected between a power input pin of the HDMI male connector and a power input pin of the HDMI port;

[0014] A plurality of the common mode inductor modules are connected respectively between the data differential signal pins of the plurality of HDMI male connectors and the data differential signal pins of the plurality of HDMI ports;

[0015] One of the common mode inductor modules is connected between the clock differential signal pin of the HDMI male connector and the clock differential signal pin of the HDMI port;

[0016] The hot-plug pull-down circuit is connected between the hot-plug signal pin of the HDMI male connector and the hot-plug signal pin of the HDMI port;

[0017] The first end of the consumer electronics control pull-up circuit is connected to the CEC control signal pin of the HDMI male connector, and the second end of the consumer electronics control pull-up circuit is respectively connected to the power input pin and the CEC control signal pin of the HDMI port;

[0018] The display data channel impedance matching circuit is connected between the serial pin of the HDMI male connector and the serial pin of the HDMI port.

[0019] Optionally, the power protection circuit includes: a first diode and a magnetic bead;

[0020] The first diode and the magnetic bead are connected in parallel between the power input pin of the HDMI male connector and the power input pin of the HDMI port;

[0021] The magnetic beads are used to eliminate interference of fixed frequencies on the power line;

[0022] The first diode is used to prevent the HDMI port from current backflow.

[0023] Optionally, the common mode inductor module includes: a common mode inductor;

[0024] The common mode inductor is connected between the data differential signal pin of the HDMI male connector and the data differential signal pin of the HDMI port;

[0025] The common mode inductor is used to filter out common mode interference on the HDMI differential line.

[0026] Optionally, the hot-swap pull-down circuit comprises: a first resistor and a first capacitor;

[0027] The first end of the first resistor and the first capacitor connected in parallel is connected to the hot plug signal pin of the HDMI male connector and the hot plug signal pin of the HDMI port and the connection end, and the second end of the first resistor and the first capacitor connected in parallel is grounded;

[0028] The first resistor is used to keep the hot-plug signal interface of the HDMI port in a stable state of a low level when there is no signal input, and the first capacitor is used to filter out high-frequency noise.

[0029] Optionally, the consumer electronics control pull-up circuit further includes: a second resistor, a second diode;

[0030] A first end of the second resistor and the second diode connected in series is connected to a connection end of a CEC control signal pin of the HDMI male connector and a CEC control signal pin of the HDMI port;

[0031] The second end of the second resistor and the second diode connected in series is connected to the power input pin of the HDMI port;

[0032] The second resistor is used to maintain a stable high level state, and the second diode is used to prevent current backflow.

[0033] Optionally, the display data channel impedance matching circuit further includes: a third resistor and a fourth resistor;

[0034] The third resistor is connected between the serial clock pin of the HDMI male connector and the serial clock pin of the HDMI port;

[0035] The fourth resistor is connected between the serial data pin of the HDMI male connector and the serial data pin of the HDMI port;

[0036] The third resistor and the fourth resistor are used for impedance matching of the signal line and absorbing reflected signals.

[0037] Optionally, the HDMI protection board circuit further includes: a first TVS filter module and a second TVS filter module;

[0038] The first TVS filter module is connected to the HDMI male connector, and the first TVS tube is used to prevent the HDMI male connector pin from being damaged and to prevent static electricity;

[0039] The second TVS filter module is connected to the HDMI port, and the second TVS filter module is used to prevent the HDMI port pins from being damaged and to prevent static electricity.

[0040] In addition, to achieve the above-mentioned purpose, the present invention also provides an HDMI protection board, which includes the HDMI protection board circuit as described above.

[0041] In addition, to achieve the above-mentioned purpose, the present invention also provides a device, which includes the HDMI protection board circuit as described above.

[0042] The HDMI protection board circuit of the present invention is connected between an HDMI male connector and an HDMI port, and the HDMI protection board circuit comprises: a power protection circuit, a plurality of common mode inductor modules, a hot plug pull-down circuit, a display data channel impedance matching circuit and a consumer electronics control pull-up circuit; the power protection circuit, the common mode inductor module, the hot plug pull-down circuit, the display data channel impedance matching circuit and the consumer electronics control pull-up circuit are respectively connected between the HDMI male connector and the HDMI port; the power protection circuit is used to eliminate interference of fixed frequency on the power line and prevent current backflow of the HDMI port; the common mode inductor module is used to filter out common mode interference on the HDMI differential line; the hot plug pull-down circuit is used to maintain a stable state of a low level and filter out high frequency clutter; the consumer electronics control pull-up circuit is used to maintain a stable state of a high level; the display data channel impedance matching circuit is used for impedance matching of the signal line and absorbing reflected signals.

[0043] Different from the traditional HDMI protection method of protecting ESD through TVS tube, the power protection circuit, the common mode inductor module, the hot plug pull-down circuit, the display data channel impedance matching circuit and the consumer electronics control pull-up circuit are respectively connected between the HDMI male head and the HDMI port, so that the present invention can filter out the common mode interference and fixed frequency interference that appear during data line transmission in the HDMI interface, prevent the problems of clutter and current backflow at the power input end, and at the same time, prevent the problems of unstable state and easy false triggering of CEC (Consumer Electronics Control), DDC (Display Data Channel) and hot plug interface when there is no signal transmission, thereby greatly improving the protection performance of the HDMI interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the circuit principle of the HDMI protection board of the present invention;

[0045] Figure 2 It is a schematic diagram of a power protection circuit of an HDMI protection board circuit of the present invention;

[0046] Figure 3 A schematic diagram of a common-mode inductor module of an HDMI protection board circuit of the present invention;

[0047] Figure 4 It is a schematic diagram of a hot-plug pull-down circuit of an HDMI protection board circuit of the present invention;

[0048] Figure 5 A schematic diagram of a consumer electronics control pull-up circuit of an HDMI protection board circuit of the present invention;

[0049] Figure 6 It is a schematic diagram of the impedance matching circuit of the display data channel of the HDMI protection board circuit of the present invention;

[0050] Figure 7 This is a schematic diagram of a first TVS filter module of an HDMI protection board circuit of the present invention;

[0051] Figure 8 A schematic diagram of a second TVS filter module of the HDMI protection board circuit of the present invention;

[0052] Fig. 9 The figure is a schematic diagram of a practical application scenario of the HDMI protection board circuit of the present invention.

[0053] Description of Figure Numbers:

[0054]

[0055]

[0056] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0057] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0058] The embodiment of the present invention provides an HDMI protection board circuit, referring to Figure 1 , Figure 1 The figure is a schematic diagram of the circuit layout of the HDMI protection board of the present invention.

[0059] The HDMI protection board circuit is connected between the HDMI male connector and the HDMI port, and the HDMI protection board circuit includes: a power protection circuit 10, a plurality of common mode inductor modules 20, a hot plug pull-down circuit 40, a display data channel impedance matching circuit 30 and a consumer electronics control pull-up circuit 50;

[0060] The first ends of the power protection circuit 10, the common mode inductor module 20, the hot plug pull-down circuit 40, the display data channel impedance matching circuit 30 and the consumer electronics control pull-up circuit 50 are respectively connected to the HDMI male connector;

[0061] The second ends of the power protection circuit 10, the common mode inductor module 20, the hot plug pull-down circuit 40, the display data channel impedance matching circuit 30 and the consumer electronics control pull-up circuit 50 are respectively connected to the HDMI port;

[0062] The power protection circuit 10 is used to eliminate the interference of fixed frequency on the power line and prevent the current backflow of the HDMI port;

[0063] The common mode inductor module 20 is used to filter out common mode interference on the HDMI differential line;

[0064] The hot-swap pull-down circuit 40 is used to maintain a stable low-level state and filter out high-frequency noise;

[0065] The consumer electronics control pull-up circuit 50 is used to maintain a stable high level state;

[0066] The display data channel impedance matching circuit 30 is used for impedance matching of the signal line to absorb the reflected signal.

[0067] In this embodiment, if Figure 1 The HDMI protection board circuit principle diagram shown in the figure, the HDMI protection board circuit is connected between the HDMI male connector and the HDMI port, and is set on the HDMI port side. The power protection circuit solves the interference problem of the noise of the power input port of the HDMI port and prevents the problem of current backflow of the HDMI port. The common-mode inductor module solves the common-mode interference that is easy to occur during data transmission on the HDMI differential line. The hot-swap pull-down circuit is used to keep the signal line in a stable low-level state when there is no input and filter out high-frequency noise.

[0068] It should be noted that the consumer electronics control is CEC, and the CEC bus is an open-drain (Open-Drain) output similar to IIC (Inter-Integrated Circuit, integrated circuit bus), which cannot output a high level. Therefore, an external pull-up resistor is required to pull it up, and the consumer electronics control pull-up circuit 50 is used to pull it to 3.3V to prevent an unknown level state.

[0069] It should be noted that the display data channel is DDC (Display Data Channel). The display data channel impedance matching circuit 30 is used for impedance matching of the signal line and absorbs the reflected signal. When the frequency of the electrical signal is relatively high, or the dv / dt is relatively large, reflection will also occur when passing through places with different impedances. For example, transmission is generated when the line passes through the PCB from the transmitting end to the receiving end. This reflected signal will be superimposed on the signal at the transmitting end, resulting in repeated transmission at the receiving end. The display data channel impedance matching circuit 30 solves the problem of absorbing the reflected signal and is used for impedance matching of the signal line.

[0070] Optionally, the power protection circuit 10 is connected between the power input pin of the HDMI male connector and the power input pin of the HDMI port;

[0071] The plurality of common mode inductor modules 20 are connected respectively between the data differential signal pins of the plurality of HDMI male connectors and the data differential signal pins of the plurality of HDMI ports;

[0072] One of the common mode inductor modules 20 is connected between the clock differential signal pin of the HDMI male connector and the clock differential signal pin of the HDMI port;

[0073] The hot-plug pull-down circuit 40 is connected between the hot-plug signal pin of the HDMI male connector and the hot-plug signal pin of the HDMI port;

[0074] The first end of the consumer electronics control pull-up circuit 50 is connected to the CEC control signal pin of the HDMI male connector, and the second end of the consumer electronics control pull-up circuit 50 is respectively connected to the power input pin and the CEC control signal pin of the HDMI port;

[0075] The display data channel impedance matching circuit 30 is connected between the serial pin of the HDMI male connector and the serial pin of the HDMI port.

[0076] In this embodiment, the pins of the HDMI male connector and the HDMI port each include a power input pin HDMI_5V, multiple data differential signal pins, a clock differential signal pin, a serial clock pin, a serial data pin, a CEC control signal pin and a hot plug signal pin.

[0077] In this embodiment, the power protection circuit is connected between the power input pin 5V_IN of the HDMI male connector and the power input pin HDMI_5V of the HDMI port. The power protection circuit solves the interference problem of the clutter of the power input port of the HDMI port and prevents the problem of current backflow of the HDMI port.

[0078] In this embodiment, the differential signal pins of HDMI include data differential signal pins and clock differential signal pins, three common-mode inductor modules are respectively connected between the three data differential signal pins of the HDMI male connector and the HDMI port, the first common-mode inductor module is connected between the first data differential signal pin of the HDMI male connector and the first data differential signal pin of the HDMI port, the second common-mode inductor module is connected between the second data differential signal pin of the HDMI male connector and the second data differential signal pin of the HDMI port, the third common-mode inductor module is connected between the third data differential signal pin of the HDMI male connector and the third data differential signal pin of the HDMI port, and one common-mode inductor module is connected between the clock differential signal pin of the HDMI male connector and the clock differential signal pin of the HDMI port.

[0079] In this embodiment, the hot-plug pull-down circuit is connected in parallel between the hot-plug signal pin HDMI_HOTPLUG_C of the HDMI male connector and the hot-plug signal pin HDMI_HOTPLUG of the HDMI port, so that the signal line maintains a stable low level and filters out high-frequency noise when there is no input.

[0080] In this embodiment, the first end of the consumer electronics control pull-up circuit 50 is connected to the CEC control signal pin HDMI_CEC_C of the HDMI male connector, and the second end of the consumer electronics control pull-up circuit 50 is respectively connected to the power input pin and the CEC control signal of the HDMI port, thereby pulling the voltage high circuit to 3.3V to prevent an unknown level state.

[0081] In this embodiment, the display data channel impedance matching circuit 30 is connected between the serial pin of the HDMI male connector and the serial pin of the HDMI port. The serial pin of the HDMI male connector includes a serial clock pin HDMI_SCL_C and a serial data pin HDMI_SDA_C, and the serial pin of the HDMI port includes a serial clock pin HDMI_SCL and a serial data pin HDMI_SDA. Thus, the reflected signal is absorbed by impedance matching of the signal line.

[0082] Optionally, the power protection circuit 10 includes: a first diode D1 and a magnetic bead P;

[0083] The first diode D1 and the magnetic bead P are connected in parallel between the power input pin 5V_IN of the HDMI male connector and the power input pin HDMI_5V of the HDMI port; the magnetic bead P is used to eliminate the interference of the fixed frequency on the power line; the first diode D1 is used to prevent the current backflow of the HDMI port.

[0084] In this embodiment, the magnetic bead P can effectively filter out the interference of fixed frequency on the power line. The first diode D1 is a Schottky diode, which is used to prevent the HDMI port from current backflow and damage the power supply device.

[0085] For example, Figure 2 The power protection circuit schematic diagram of the HDMI protection board circuit shown in the figure, the power protection circuit may also include a fifth resistor R5 and a sixth resistor R6, the first end of the fifth resistor R5 and the sixth resistor R6 connected in parallel is connected to the power input pin HDMI_5V of the HDMI port, the second end of the fifth resistor R5 is connected to the serial clock pin HDMI_SCL of the HDMI port, and the second end of the sixth resistor R6 is connected to the serial data pin HDMI_SDA of the HDMI port. Since the IIC signal output is open-drain (Open-Drain), it plays the role of pulling up the IIC (Inter-Integrated Circuit) signal line of the DDC signal.

[0086] Optionally, the common mode inductor module 20 includes: a common mode inductor L;

[0087] The common-mode inductor L is connected between the differential signal pins of the HDMI male connector and the differential signal pins of the HDMI port; the common-mode inductor is used to filter out common-mode interference on the HDMI differential line.

[0088] It should be noted that the differential signal pins of HDMI include data differential signal pins and clock differential signal pins, the data differential pins of the HDMI male connector include a first data differential pin, a second data differential pin and a third data differential pin, the first data differential pin includes HDMI_TX0P_C and HDMI_TX0N_C, the second data differential pin includes HDMI_TX1P_C and HDMI_TX1N_C, the third data differential pin includes HDMI_TX2P_C and HDMI_TX2N_C, the clock differential pins of the HDMI male connector include HDMI_TXCLKP_C and HDMI_TXCLKP_C, and the common-mode inductor L1 is composed of two coils. When a common-mode current flows through the common-mode inductor, the magnetic fluxes in the magnetic ring are superimposed on each other, so that it has a considerable inductance, which suppresses the common-mode current.

[0089] For example, Figure 3The common-mode inductor module schematic diagram of the HDMI protection board circuit shown in the figure, taking the first data differential pin as an example, the first pin of the common-mode inductor L is connected to the first data differential pin HDMI_TX0N_C of the HDMI male connector, the fourth pin of the common-mode inductor is connected to the first data differential pin HDMI_TX0P_C of the HDMI male connector, the second pin of the common-mode inductor is connected to the first data differential pin HDMI_TX0N of the HDMI port, and the fourth pin of the common-mode inductor is connected to the first data differential pin HDMI_TX0P of the HDMI male connector. Similarly, the connection method of the second data differential pin, the third data differential pin, the clock differential signal pin and the common-mode inductor is the same as above.

[0090] It should be noted that the common-mode inductor module may also include a seventh resistor R7 and an eighth resistor R8, the first end of the seventh resistor R7 is connected to the fourth pin of the common-mode inductor L, the second end of the seventh resistor R7 is connected to the third pin of the common-mode inductor L, the first end of the eighth resistor R8 is connected to the first pin of the common-mode inductor L, and the second end of the eighth resistor R8 is connected to the second pin of the common-mode inductor L. It should be understood that the seventh resistor R7 and the eighth resistor R8 are applied to the connection between the first data differential pin, the second data differential pin, the third data differential pin and the clock differential signal pin and the common-mode inductor. It should be understood that the seventh resistor R7 and the eighth resistor R8 are compatible with a common-mode inductor L. In actual application, the cost of the common-mode inductor L is reduced by the seventh resistor R7 and the eighth resistor R8.

[0091] Optionally, the hot-swap pull-down circuit 40 includes: a first resistor R1 and a first capacitor C1;

[0092] The first end of the first resistor R1 and the first capacitor C1 connected in parallel is connected to the connection end of the hot plug signal pin HDMI_HUTPLUG_C of the HDMI male connector and the hot plug signal pin HDMI_HUTPLUG of the HDMI port, and the second end of the first resistor R1 and the first capacitor C1 connected in parallel is grounded;

[0093] The first resistor R1 is used to keep the hot-plug signal interface HDMI_HUTPLUG of the HDMI port in a stable low-level state when there is no signal input, and the first capacitor C1 is used to filter out high-frequency noise.

[0094] It should be noted that the hot plug signal is high-start, and HDMI is converted to the on state by internally pulling up when it is turned on. Therefore, it is necessary to lower the voltage of the signal line through the first resistor R1 so that the signal line is in a stable low-level state when there is no input. The first capacitor C1 plays a role in filtering out high-frequency noise.

[0095] For example, Figure 4The hot-plug pull-down circuit schematic diagram of the HDMI protection board circuit shown, the hot-plug pull-down circuit may also include a ninth resistor R9, the ninth resistor R9 is connected between the hot-plug signal pin HDMI_HUTPLUG_C of the HDMI male connector and the hot-plug signal pin HDMI_HUTPLUG of the HDMI port, the ninth resistor R9 plays a role of current limiting to prevent excessive current from burning out the terminal or chip.

[0096] Optionally, the consumer electronics control pull-up circuit 50 further includes: a second resistor R2, a second diode D2;

[0097] A first end of the second resistor R2 and the second diode D2 connected in series is connected to a connection end of a CEC control signal pin HDMI_CEC_C of the HDMI male connector and a CEC control signal pin HDMI_CEC of the HDMI port;

[0098] The second end of the second resistor R2 and the second diode D2 connected in series is connected to the power input pin HDMI_5V of the HDMI port;

[0099] The second resistor R2 is used to maintain a stable high level state, and the second diode D2 is used to prevent current backflow.

[0100] In this embodiment, if Figure 5 The schematic diagram of the consumer electronics control pull-up circuit of the HDMI protection board circuit shown in the figure, the consumer electronics control pull-up circuit 50 may also include a tenth resistor R10, an eleventh resistor R11 and a twelfth resistor R12, the first end of the tenth resistor R10 and the eleventh resistor R11 connected in parallel is connected to the second end of the second diode D2, the second end of the tenth resistor R10 is grounded, the eleventh resistor R11 is connected to the power input pin HDMI_5V of the HDMI port, the tenth resistor R10 and the eleventh resistor R11 play the role of reducing the 5V voltage to 3.3V, and are pulled up by the second resistor R2 to maintain a stable state of a high level, the twelfth resistor R12 is connected between the CEC control signal pin HDMI_CEC_C of the HDMI male connector and the CEC control signal pin HDMI_CEC of the HDMI port, and plays a role of current limiting to prevent excessive current from burning out the terminal or chip.

[0101] Optionally, the display data channel impedance matching circuit 30 further includes: a third resistor R3 and a fourth resistor R4;

[0102] The third resistor R3 is connected between the serial clock pin HDMI_SCL_C of the HDMI male connector and the serial clock pin HDMI_SCL of the HDMI port;

[0103] The fourth resistor R4 is connected between the serial data pin HDMI_SDA_C of the HDMI male connector and the serial data pin HDMI_SDA of the HDMI port;

[0104] The third resistor R3 and the fourth resistor R4 are used for impedance matching of the signal line and absorbing reflected signals.

[0105] In this embodiment, if Figure 6 The display data channel impedance matching circuit schematic diagram of the HDMI protection board circuit shown in the figure, the DDC signal line includes a serial clock signal line SCL and a serial data signal line SDA, the third resistor R3 and the fourth resistor R4 are used for impedance matching of the signal line and absorb reflected signals. When the frequency of the electrical signal is relatively high, or the dv / dt is relatively large, reflections will also occur when passing through places with different impedances. For example, when the transmission is generated from the transmitting end through the PCB routing to the receiving end, the reflected signal will be superimposed on the signal of the transmitting end, resulting in repeated transmission at the receiving end. The absorption of reflected signals is solved by the third resistor R3 and the fourth resistor R4, which are used for impedance matching of the signal line.

[0106] The HDMI protection board circuit of the present invention is connected between an HDMI male connector and an HDMI port, and the HDMI protection board circuit comprises: a power protection circuit, a plurality of common mode inductor modules, a hot plug pull-down circuit, a display data channel impedance matching circuit 30 and a consumer electronics control pull-up circuit 50; the power protection circuit, the common mode inductor module, the hot plug pull-down circuit, the display data channel impedance matching circuit 30 and the consumer electronics control pull-up circuit 50 are respectively connected between the HDMI male connector and the HDMI port; the power protection circuit is used to eliminate the interference of fixed frequency on the power line and prevent the current backflow of the HDMI port; the common mode inductor module is used to filter out the common mode interference on the HDMI differential line; the hot plug pull-down circuit is used to maintain a stable state of a low level and filter out high frequency clutter; the consumer electronics control pull-up circuit is used to maintain a stable state of a high level; the display data channel impedance matching circuit is used for impedance matching of the signal line and absorbing the reflected signal.

[0107] The present invention connects the power protection circuit, the common mode inductor module, the hot plug pull-down circuit, the display data channel impedance matching circuit and the consumer electronics control pull-up circuit respectively between the HDMI male head and the HDMI port, thereby filtering out the common mode interference and the fixed frequency interference occurring during the data line transmission in the HDMI interface, preventing the problems of clutter and current backflow at the power input end, and preventing the problems of CEC (Consumer Electronics Control, consumer electronics control), DDC (Display Data Channel, display data channel) and the hot plug interface being unstable and easy to be triggered by mistake when there is no signal transmission, thereby greatly improving the protection performance of the HDMI interface.

[0108] Optionally, based on the first embodiment of the HDMI protection board circuit of the present invention as described above, a second embodiment of the HDMI protection board circuit of the present invention is proposed.

[0109] In some feasible embodiments, the HDMI protection board circuit further includes: a first TVS filter module 60 and a second TVS filter module 70;

[0110] The first TVS filter module 60 is connected to the HDMI male connector, and the first TVS tube 60 is used to prevent the HDMI male connector pin from being damaged and to prevent static electricity;

[0111] The second TVS filter module 70 is connected to the HDMI port, and is used to prevent the pins of the HDMI port from being damaged and to prevent static electricity.

[0112] In this embodiment, a first TVS filter module 60 is connected between the HDMI male connector and the common-mode inductor module 20, and a second TVS filter module 70 is connected between the common-mode inductor module 20 and the HDMI port, so that the voltage of the HDMI port is clamped at a fixed value when it is large, thereby preventing the voltage of the HDMI port from being too high and preventing ESD (Electro-Static discharge).

[0113] For example, Figure 7The first TVS filter module schematic diagram of the HDMI protection board circuit shown in the figure, the first TVS filter module 60 includes a first TVS chip U1 and a second TVS chip U2, the first pin and the tenth pin of the first TVS chip U1 are respectively connected to the third data differential signal HDMI_TX2P_C of the HDMI male connector, the second pin and the ninth pin of the first TVS chip U1 are respectively connected to the third data differential signal HDMI_TX2N_C of the HDMI male connector, the fourth pin and the seventh pin of the first TVS chip U1 are respectively connected to the second data differential signal HDMI_TX1P_C of the HDMI male connector, the fifth pin and the sixth pin of the first TVS chip U1 are respectively connected to the third data differential signal HDMI_TX2N_C of the HDMI male connector, It is connected to the third data differential signal HDMI_TX1N_C of the HDMI male connector, the 1st pin and the 10th pin of the second TVS chip U2 are respectively connected to the first data differential signal HDMI_TX0P_C of the HDMI male connector, the 2nd pin and the 9th pin of the second TVS chip U2 are respectively connected to the first data differential signal HDMI_TX0N_C of the HDMI male connector, the 4th pin and the 7th pin of the second TVS chip U2 are respectively connected to the clock differential signal HDMI_TXCLKP_C of the HDMI male connector, and the 5th pin and the 6th pin of the second TVS chip U2 are respectively connected to the clock differential signal HDMI_TXCLKN_C of the HDMI male connector.

[0114] For example, Figure 8The second TVS filter module schematic diagram of the HDMI protection board circuit shown in the figure, the second TVS filter module 70 includes a third TVS chip U3, a fourth TVS chip U4 and a fifth TVS chip U5, the first pin and the tenth pin of the third TVS chip U3 are respectively connected to the third data differential signal HDMI_TX2P of the HDMI port, the second pin and the ninth pin of the first TVS chip U1 are respectively connected to the third data differential signal HDMI_TX2N of the HDMI port, the fourth pin and the seventh pin of the first TVS chip U1 are respectively connected to the second data differential signal HDMI_TX1P_C of the HDMI port, the fifth pin and the sixth pin of the first TVS chip U1 are respectively connected to the third data differential signal HDMI_TX1N_C of the HDMI port, the first pin and the tenth pin of the fourth TVS chip U2 are respectively connected to the first data differential signal HDMI_TX0P_C of the HDMI port, the second pin and the ninth pin of the second TVS chip U2 are respectively connected to the HDMI The first data differential signal HDMI_TX0N_C of the port is connected, the 4th pin and the 7th pin of the second TVS chip U2 are respectively connected to the clock differential signal HDMI_TXCLKP_C of the HDMI port, the 5th pin and the 6th pin of the second TVS chip U2 are respectively connected to the clock differential signal HDMI_TXCLKN_C of the HDMI port, the 1st pin of the fifth TVS chip U5 is connected to the CEC control signal pin HDMI_CEC of the HDMI port, the 2nd pin of the fifth TVS chip U5 is grounded, the 3rd pin of the fifth TVS chip U5 is connected to the serial clock pin HDMI_SCL of the HDMI port, the 4th pin of the fifth TVS chip U5 is connected to the hot plug signal pin HDMI_HUTPLUG of the HDMI port, the 5th pin of the fifth TVS chip U5 is connected to the power input pin HDMI_5V of the HDMI port, and the 6th pin of the fifth TVS chip U5 is connected to the serial data pin HDMI_SDA of the HDMI port.

[0115] Please note that, please refer to Fig. 9 , Fig. 9 FIG. 1 is a schematic diagram of an actual application scenario of the HDMI protection board circuit of the present invention. In an actual application scenario, the placement positions of various modules are as follows: Fig. 9As shown, the first TVS filter module 60 is placed between the HDMI male connector and the common-mode inductor module 20, and the second TVS filter module 70 is placed between the common-mode inductor module 20 and the HDMI port, so that a pair of clock signals and three pairs of data signals are filtered by the first TVS filter module 60, and a pair of clock signals, three pairs of data signals, DDC signals, HOTPLUG signals, and CEC signals are filtered by the second TVS filter module 70. In addition, the first TVS chip U1 and the second TVS chip U2 are used to prevent the HDMI male connector from being damaged by the pins and to prevent static electricity, and the third TVS chip U3, the fourth TVS chip U4, and the fifth TVS chip U5 are used to prevent the HDMI port from being damaged by the pins and to prevent static electricity.

[0116] In this embodiment, the HDMI protection board circuit of the present invention is connected in parallel between the HDMI male connector and the common-mode inductor module, and the second TVS filter module is connected in parallel between the common-mode inductor module and the HDMI port, so that the present invention can filter out the common-mode interference and fixed-frequency interference that occur during data line transmission in the HDMI interface, and prevent the problems of clutter and current backflow at the power input end. At the same time, it prevents the problems of CEC (Consumer Electronics Control), DDC (Display Data Channel) and hot-plug interfaces being unstable and prone to false triggering when there is no signal transmission, and prevents the pins of the HDMI male connector and the HDMI port from being damaged, and prevents ESD problems, thereby greatly improving the protection performance of the HDMI interface.

[0117] An embodiment of the present invention further provides an HDMI protection board, which includes the HDMI protection board circuit in any of the above embodiments.

[0118] In this embodiment, thanks to the above-mentioned HDMI protection board circuit, the HDMI protection board of this embodiment has the same technical effect as the above-mentioned HDMI protection board circuit, which will not be repeated here.

[0119] An embodiment of the present invention further provides a device, which includes the HDMI protection board circuit in any of the above embodiments.

[0120] In this embodiment, thanks to the above-mentioned HDMI protection board circuit, the device of this embodiment has the same technical effect as the above-mentioned HDMI protection board circuit, which will not be repeated here.

[0121] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0122] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0123] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0124] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An HDMI protection board circuit, characterized in that: The HDMI protection board circuit is connected between the HDMI male connector and the HDMI port, and the HDMI protection board circuit includes: a power protection circuit, a plurality of common mode inductor modules, a hot plug pull-down circuit, a display data channel impedance matching circuit, and a consumer electronics control pull-up circuit; The first ends of the power protection circuit, the plurality of common mode inductor modules, the hot-swap pull-down circuit, the display data channel impedance matching circuit and the consumer electronics control pull-up circuit are respectively connected to the HDMI male connector; The second ends of the power protection circuit, the plurality of common mode inductor modules, the hot plug pull-down circuit, the display data channel impedance matching circuit and the consumer electronics control pull-up circuit are respectively connected to the HDMI port; The power protection circuit is used to eliminate the interference of fixed frequency on the power line and prevent the current backflow of the HDMI port, and includes: a first diode and a magnetic bead, wherein the first diode and the magnetic bead are connected in parallel between the power input pin of the HDMI male connector and the power input pin of the HDMI port, the magnetic bead is used to eliminate the interference of fixed frequency on the power line, and the first diode is used to prevent the current backflow of the HDMI port; The common-mode inductor module is used to filter out common-mode interference on the HDMI differential line, and includes: a common-mode inductor, the common-mode inductor is connected between the data differential signal pin of the HDMI male connector and the data differential signal pin of the HDMI port, and the common-mode inductor is used to filter out common-mode interference on the HDMI differential line; The hot-plug pull-down circuit is used to maintain a stable state of a low level and filter out high-frequency noise, and includes: a first resistor and a first capacitor, wherein a first end of the first resistor and the first capacitor connected in parallel is connected to a hot-plug signal pin of an HDMI male connector and a connection end of a hot-plug signal pin of the HDMI port, and a second end of the first resistor and the first capacitor connected in parallel is grounded, the first resistor is used to maintain a stable state of a low level when no signal is input to the hot-plug signal interface of the HDMI port, and the first capacitor is used to filter out high-frequency noise; The consumer electronics control pull-up circuit is used to maintain a stable state of a high level, and includes: a second resistor and a second diode, wherein a first end of the second resistor and the second diode connected in series is connected to a connection end of a CEC control signal pin of the HDMI male connector and a CEC control signal pin of the HDMI port, and a second end of the second resistor and the second diode connected in series is connected to a power input pin of the HDMI port, wherein the second resistor is used to maintain a stable state of a high level, and the second diode is used to prevent current backflow; The display data channel impedance matching circuit is used for impedance matching of the signal line and absorbing the reflected signal, and includes: a third resistor and a fourth resistor, the third resistor is connected between the serial clock pin of the HDMI male connector and the serial clock pin of the HDMI port, the fourth resistor is connected between the serial data pin of the HDMI male connector and the serial data pin of the HDMI port, the third resistor and the fourth resistor are used for impedance matching of the signal line and absorbing the reflected signal.

2. The HDMI protection board circuit according to claim 1, wherein: The power protection circuit is connected between the power input pin of the HDMI male connector and the power input pin of the HDMI port; A plurality of the common mode inductor modules are connected respectively between the data differential signal pins of the plurality of HDMI male connectors and the data differential signal pins of the plurality of HDMI ports; One of the common mode inductor modules is connected between the clock differential signal pin of the HDMI male connector and the clock differential signal pin of the HDMI port; The hot-plug pull-down circuit is connected between the hot-plug signal pin of the HDMI male connector and the hot-plug signal pin of the HDMI port; The first end of the consumer electronics control pull-up circuit is connected to the CEC control signal pin of the HDMI male connector, and the second end of the consumer electronics control pull-up circuit is respectively connected to the power input pin and the CEC control signal pin of the HDMI port; The display data channel impedance matching circuit is connected between the serial pin of the HDMI male connector and the serial pin of the HDMI port.

3. The HDMI protection board circuit as claimed in claim 2, characterized in that: The HDMI protection board circuit also includes: a first TVS filter module and a second TVS filter module; The first TVS filter module is connected to the HDMI male connector, and the first TVS tube is used to prevent the HDMI male connector pin from being damaged and to prevent static electricity; The second TVS filter module is connected to the HDMI port, and the second TVS filter module is used to prevent the HDMI port pins from being damaged and to prevent static electricity.

4. An HDMI protection plate, characterized in that: The HDMI protection board comprises the HDMI protection board circuit according to any one of claims 1 to 3.

5. An HDMI protection device, characterized in that: The HDMI protection device comprises the HDMI protection board circuit according to any one of claims 1 to 3.

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