CN215835479U - HDMI interface protection circuit and mainboard - Google Patents

Abstract

The utility model relates to the technical field of electronic circuits, and discloses an HDM I interface protection circuit and a mainboard, wherein the HDM I interface protection circuit comprises: the HDM Power supply comprises a Power supply module A with a +5V Power supply output end, a current limiting switch circuit module B for limiting the current when detecting that short-circuit current appears on a +5V Power pin of an HDM I interface, and an HDM I interface module C with a +5V Power pin; the +5V Power output end of the Power module A is connected with the input end of the current-limiting switch circuit module B, and the output end of the current-limiting switch circuit module B is connected with the +5V Power pin in the HDM I interface module C. Compared with the prior art, the technical scheme of the utility model can provide a structure of the protection circuit, when the mainboard of the electronic equipment with the video output function is connected with an external display device, and when the larger current of the +5V Power pin of the HDM I interface is detected, the Power supply path is cut off in time, so that the mainboard of the electronic equipment is protected.

Description

HDMI interface protection circuit and mainboard

Technical Field

The utility model relates to the technical field of electronic circuits, in particular to an HDMI interface protection circuit and a mainboard.

Background

A High Definition Multimedia Interface (HDMI) is an all-digital video and audio transmission Interface, which can be used to transmit uncompressed audio and video signals. The HDMI interface is a proprietary type interface suitable for video transmission, with a maximum transmission rate of 2.25GB/s, without the need for digital-to-analog or analog-to-digital conversion prior to signal transmission.

At present, some common electronic devices (such as desktop computers, notebook computers, tablet computers, and the like) with video output functions in the market integrate HDMI interfaces on their motherboards, so that videos can be transmitted to external devices (such as a display and the like) connected to the motherboards of the electronic devices through the HDMI interfaces for display, thereby obtaining effects of different visual experiences with the electronic devices.

However, the inventor of the present invention found in research that, when a main board of an electronic device is connected to an external display device through an HDMI interface, a Power supply of the main board is directly connected to a Power pin of the external display device through the HDMI interface, that is, there is a structure with few protection circuits in the prior art, when the HDMI interface is used for a long time and a short circuit occurs in a +5V Power pin, the main board may be burned out, which may cause permanent damage to the electronic device.

Accordingly, there is a need for improvement in response to the problems of the prior art.

Disclosure of Invention

In view of the above, it is necessary to provide an HDMI interface protection circuit and a motherboard, and compared with the prior art, a structure of the protection circuit can be provided, when the motherboard of an electronic device with a video output function is connected to an external display device, and when a large current is detected at the +5V Power pin of the HDMI interface, a Power supply path is cut off in time, so as to protect the motherboard of the electronic device.

In order to solve the above technical problem, the present invention provides an HDMI interface protection circuit, including: the HDMI controller comprises a Power supply module A with a +5V Power supply output, a current limiting switch circuit module B for limiting the current when the short-circuit current of a +5V Power pin of an HDMI interface is detected, and an HDMI interface module C with a +5V Power pin;

the +5V Power output of the Power module A is connected with the input of the current-limiting switch circuit module B, and the output of the current-limiting switch circuit module B is connected with the +5V Power pin in the HDMI interface module C.

Optionally, the current-limiting switch circuit module B includes a current-limiting switch chip, the current-limiting switch chip has first to fifth pins, the first pin is connected to the +5V Power pin of the HDMI interface module C as an output, the second pin is grounded, the third pin is grounded through a first resistor, the fourth pin is connected to the +5V Power output of the Power module a through a second resistor, and the fifth pin is connected to the +5V Power output of the Power module a as an input.

Optionally, the first resistor is a 10K ohm resistor.

Optionally, the second resistor is a 10K ohm resistor.

Optionally, the fifth pin is grounded through a first capacitor.

Optionally, the parameter specification of the first capacitor is 10 uF/6.3V.

Optionally, the +5V Power pin in the HDMI interface module C is grounded through a second capacitor.

Optionally, the parameter specification of the second capacitor is 0.1 uF/10V.

Optionally, the current-limiting switch circuit module B includes an MF-FSMF035X-2 self-recovery fuse.

In order to solve the above technical problem, the present invention further provides a motherboard integrated with the HDMI interface protection circuit.

The technical scheme of the embodiment of the utility model has the beneficial effects that:

the HDMI interface protection circuit provided by the embodiment of the utility model comprises: the HDMI Power supply comprises a Power supply module A with a +5V Power supply output, a current limiting switch circuit module B for limiting the current when short-circuit current of a +5V Power pin of the HDMI interface is detected, and an HDMI interface module C with a +5V Power pin. Wherein, Power module A's +5V Power output connects current-limiting switch circuit module B's input, current-limiting switch circuit module B's output connection +5V Power pin in the HDMI interface module C cuts off the Power supply route when the heavy current of short circuit appears in the +5V Power pin of HDMI interface to can protect electronic equipment's mainboard.

Drawings

Fig. 1 is a schematic circuit structure diagram of an HDMI interface protection circuit according to an embodiment of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the description relating to "first", "second", etc. in the present invention is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

In the description of the embodiments of the present invention, it is to be understood that, in the description of the present invention, "a plurality" means two or more unless otherwise specified. "and/or" describes the association relationship of the associated objects, meaning that three relationships may exist, e.g., A and/or B. Can represent that: a exists alone, A and B exist simultaneously, and B exists alone.

It will also be understood that when an element is referred to as being "fixed" or "disposed" or "connected" to another element, it can be directly or indirectly secured to the other element. The terms "upper", "lower", "outer", "distal", "far away", and the like, refer to an orientation or position based on that shown in the drawings, which is for convenience of description only and is not to be construed as limiting the present disclosure.

Referring to fig. 1, in one embodiment of the present invention, an HDMI interface protection circuit is provided. The HDMI interface protection circuit can protect a mainboard of an electronic device with a video output function when the electronic device is connected with an external display. The HDMI interface may be integrated on a motherboard of the electronic device. The input end of the HDMI interface protection circuit is connected with the power output of the mainboard, and the output end of the HDMI interface protection circuit is connected with the power pin of the HDMI interface.

In the embodiment of fig. 1, the present invention provides an HDMI interface protection circuit, including: the HDMI controller comprises a Power supply module A with a +5V Power supply output end, a current limiting switch circuit module B for limiting the current (for example, cutting off the current inflow) when the short-circuit current of the +5V Power pin of the HDMI interface is detected, and an HDMI interface module C with a +5V Power pin; the +5V Power output end of the Power module A is connected with the input end of the current-limiting switch circuit module B, and the output end of the current-limiting switch circuit module B is connected with the +5V Power pin in the HDMI interface module C.

More specifically, the power module a may have various voltage outputs, such as +12V, +5V, +3.3V, and the like, and the power module may include a voltage conversion circuit therein. And the 18PIN defined by the HDMI interface is the power input, specifically the +5V specification. Therefore, the +5V output of the power supply module A is connected with the input of the module B.

In the embodiment of fig. 1, the current limit switch circuit module B includes a current limit switch chip. In this embodiment, the current limit switch chip may be an LPW5208B5F chip, or may be a chip of another type in other embodiments. Specifically, the LPW208B5F chip has first to fifth PINs, the first PIN is connected to the +5V Power PIN (18PIN) of the HDMI interface module C as an output, the second PIN is grounded, the third PIN is grounded through a first resistor, the fourth PIN is connected to the +5V Power output of the Power module a through a second resistor by pulling up, and the fifth PIN is connected to the +5V Power output of the Power module a as an input. The large current detected by the LPW5208B5F chip may be a current exceeding 1A, and if the current of the +5V Power pin of the HDMI interface is detected to exceed 1A, it is determined that a short circuit has occurred.

In the embodiment of fig. 1, the first resistor R1 is a 10K ohm resistor and the second resistor R2 is a 10K ohm resistor.

Further, the embodiment shown in fig. 1 may include a filter capacitor, the fifth pin is grounded through a first capacitor C1, and the first capacitor has a parameter specification of 10uF/6.3V, wherein the capacitance is 10uF and the withstand voltage is 6.3V.

In the embodiment of fig. 1, the module C may be an HDMI socket disposed on a motherboard. According to the definition of the HDMI interface, 18PIN is the +5V Power PIN in the present embodiment. The definition and connection mode of other pins of the HDMI interface can refer to the prior art.

The above embodiment adopts the current-limiting IC for current-limiting protection, and the working principle of the current-limiting IC is that when overload and short-circuit faults occur, the load current reaches several amperes, and an accurate current-limiting circuit is required to provide protection for the power tube and the input power supply. For MOS devices, the current is easily controlled only when operating in the saturation region. The current limiting is realized by feeding back the load voltage and regulating the output voltage of a Charge-Pump (Charge-Pump). Under normal load conditions, a sufficiently high gate drive voltage is generated by the charge pump to operate the power transistor in a deep linear region to reduce conduction losses from the input power supply (VIN) to the load Voltage (VOUT). When the Current of the power tube is higher than the Current Limit, the Current detection circuit outputs a high level to the Over-Current protection circuit (Over Current Limit), the Over-Current protection circuit feeds back the load voltage to the charge pump through feedback, and the output of the charge pump is regulated, so that the working state of the power tube is changed from a linear region to a saturation region, the Current of the power tube is limited, and the purpose of protecting the power tube is achieved.

In an alternative embodiment, the protection circuit of module B may be replaced by a fuse, such as but not limited to MF-FSMF035X-2 self-healing fuse.

The action principle of the self-recovery fuse is dynamic balance of energy, the current flowing through the self-recovery fuse generates a certain degree of heat (the self-recovery fuse has resistance values) due to the heat effect of the current, all or part of the generated heat is dissipated to the environment, and the temperature of the self-recovery fuse element can be increased without dissipating the heat. The temperature is lower during normal operation, and the generated heat and the dissipated heat reach balance. The self-healing fuse element is in a low resistance state and the self-healing fuse is not active, as the current through the self-healing fuse element increases or the ambient temperature rises, but the self-healing fuse remains inactive if a balance of generated heat and dissipated heat is reached. When the current or ambient temperature increases again, the self-healing fuse reaches a higher temperature. If the current or the ambient temperature continues to increase again, the generated heat is larger than the heat emitted, so that the temperature of the self-recovery fuse element increases suddenly, at this stage, a very small temperature change can cause a great increase in the resistance value, at this time, the self-recovery fuse element is in a high-resistance protection state, the current is limited by the increase of the impedance, and the current drops suddenly in a very short time, so that the circuit equipment is protected from being damaged, and as long as the heat generated by the applied voltage is enough for the heat emitted by the self-recovery fuse element, the self-recovery fuse element in the changing state can be always in an action state (high resistance). The self-healing fuse is automatically restored when the applied voltage is removed.

The HDMI interface protection circuit provided by the embodiment of the utility model can be integrated in a mainboard, so that the mainboard can be protected when a large current is detected, and the mainboard is prevented from being burnt.

The technical scheme of the embodiment of the utility model has the beneficial effects that:

the HDMI interface protection circuit provided in the embodiment of the present invention: the HDMI Power supply comprises a Power supply module A with a +5V Power supply output, a current limiting switch circuit module B for limiting the current when short-circuit current of a +5V Power pin of the HDMI interface is detected, and an HDMI interface module C with a +5V Power pin. Wherein, Power module A's +5V Power output connects current-limiting switch circuit module B's input, current-limiting switch circuit module B's output connection +5V Power pin in the HDMI interface module C cuts off the Power supply route when the heavy current of short circuit appears in the +5V Power pin of HDMI interface to can protect electronic equipment's mainboard.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof.

The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference signs in the claims shall not be construed as limiting the claim concerned.

Furthermore, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. A plurality of units or means recited in the system claims may also be implemented by one unit or means in software or hardware. The terms second, etc. are used to denote names, but not any particular order.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims (10)

1. An HDMI interface protection circuit, comprising: the HDMI controller comprises a Power supply module A with a +5V Power supply output end, a current limiting switch circuit module B for limiting the current when short-circuit current appears in a +5V Power pin of an HDMI interface, and an HDMI interface module C with a +5V Power pin;

the +5V Power output end of the Power module A is connected with the input end of the current-limiting switch circuit module B, and the output end of the current-limiting switch circuit module B is connected with the +5V Power pin in the HDMI interface module C.

2. The HDMI interface protection circuit of claim 1, wherein the current limit switch circuit module B comprises a current limit switch chip, the current limit switch chip has first to fifth pins, the first pin is connected as an output to the +5V Power pin of the HDMI interface module C, the second pin is grounded, the third pin is grounded through a first resistor, the fourth pin is connected as an input to the +5V Power output of the Power module A through a second resistor, and the fifth pin is connected as an input to the +5V Power output of the Power module A.

3. The HDMI interface protection circuit of claim 2, wherein said first resistor is a 10K ohm resistor.

4. The HDMI interface protection circuit of claim 2, wherein the second resistor is a 10K ohm resistor.

5. The HDMI interface protection circuit of claim 2, wherein the fifth pin is grounded through a first capacitor.

6. The HDMI interface protection circuit of claim 5, wherein the first capacitor has a parameter specification of 10 uF/6.3V.

7. The HDMI interface protection circuit of claim 2, wherein the +5V Power pin of the HDMI module C is grounded via a second capacitor.

8. The HDMI interface protection circuit of claim 7, wherein the second capacitor has a parameter specification of 0.1 uF/10V.

9. The HDMI interface protection circuit of claim 1, wherein the current limiting switch circuit module B comprises a self-healing fuse.

10. A motherboard, wherein the HDMI interface protection circuit according to any one of claims 1 to 9 is integrated.

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