An HDMI interface and its anti-backflow circuit

Abstract

This utility model discloses an HDMI interface backflow prevention circuit, including a power supply and a voltage conversion unit. The input terminal of the voltage conversion unit is electrically connected to the power supply, and the output terminal of the voltage conversion unit is used to output a low DC voltage. The circuit also includes: a voltage regulator unit, the first terminal of which is electrically connected to the input terminal of the power supply and the voltage conversion unit, and the second terminal of which is grounded; a current limiting chip U1, the enable control terminal of which is electrically connected to the second terminal of which is electrically connected, and the input terminal of which is connected to the output terminal of which is the voltage conversion unit; and an HDMI output port, which is electrically connected to the output terminal of which is the current limiting chip U1. By setting up the voltage regulator unit and the current limiting chip U1, this utility model ensures that when the power supply is not turned on or the power supply is down, if the HDMI output port is mistakenly connected to an external HDMI power supply, the current limiting chip U1 can shut off the current output and input, preventing the external HDMI power supply from reaching the power circuit of this device through the current limiting chip U1, thus preventing any malfunction of the device.

Description

Technical Field

[0001] This utility model relates to the field of hardware circuit technology, and in particular to an HDMI interface and its anti-backflow circuit. Background Technology

[0002] In the power control design of HDMI interface devices, the traditional solution uses a single MOSFET element to control the power supply path from the power supply line to the HDMI port.

[0003] However, this architecture has a significant drawback: when the device is connected as a slave to another powered HDMI output device, the external device's HDMI power supply creates a reverse current path through the parasitic body diode of the MOSFET element. Therefore, this reverse current flows backward along the power supply line into the unpowered power circuitry of this device and propagates to other potentially affected lines, causing malfunctions in this device. Utility Model Content

[0004] In view of this, the present invention provides an HDMI interface and its anti-backflow circuit, which helps to prevent current from flowing back into the power circuit of the device when it is not powered on, thereby reducing the failure rate of the device.

[0005] In a first aspect, this utility model provides an HDMI interface backflow prevention circuit, including a power supply and a voltage conversion unit. The input terminal of the voltage conversion unit is electrically connected to the power supply, and the output terminal of the voltage conversion unit is used to output a low DC voltage. The circuit further includes: a voltage regulator unit, the first terminal of which is electrically connected to the power supply and the input terminal of the voltage conversion unit, and the second terminal of which is grounded; a current limiting chip U1, the enable control terminal of which is electrically connected to the second terminal of the voltage regulator unit, and the input terminal of which is connected to the output terminal of the voltage conversion unit; and an HDMI output port, which is electrically connected to the output terminal of the current limiting chip U1.

[0006] Compared with existing technologies, the beneficial effects of the HDMI interface backflow prevention circuit provided by this utility model are as follows: By setting up a voltage regulator unit and a current limiting chip U1, when the power is not turned on or the power is lost, if the HDMI output port is mistakenly connected to an external HDMI power output, the voltage regulator unit loses power, and the enable control terminal of the current limiting chip U1 is connected to ground. The enable control terminal changes from a high level to a low level, and the current limiting chip U1 can shut off the current output and input, so that the external HDMI power cannot reach the power circuit of this device through the current limiting chip U1, thus preventing the device from malfunctioning. Therefore, this utility model provides a hardware architecture that helps to prevent current from flowing backward into the unpowered power circuit of this device, reducing the failure rate of device operation.

[0007] Furthermore, the current limiting chip U1 includes: a first diode D1, the anode of the first diode D1 being electrically connected to the output terminal of the voltage conversion unit; and a second diode D2, the cathode of the second diode D2 being electrically connected to the cathode of the first diode D1, and the anode of the second diode D2 being electrically connected to the HDMI output port.

[0008] Furthermore, the current limiting chip U1 further includes: a switching unit, the first end of which is electrically connected to the anode of the first diode D1, and the second end of which is electrically connected to the anode of the second diode D2; and a control unit, the control terminal of which is electrically connected to the controlled terminal of the switching unit, and the first end of which serves as the enable control terminal of the current limiting chip U1.

[0009] Furthermore, the switching unit is a first MOS transistor Q1, the first diode D1 and the second diode D2 are integrated between the source and drain of the first MOS transistor Q1, and the gate of the first MOS transistor Q1 serves as the controlled terminal of the switching unit.

[0010] Furthermore, the voltage regulator unit includes a Zener diode D3, with the anode of the Zener diode D3 serving as the second terminal of the voltage regulator unit and the cathode of the Zener diode D3 serving as the first terminal of the voltage regulator unit.

[0011] Furthermore, the first end of the first resistor R1 is electrically connected to the ISET pin of the current limiting chip U1, and the second end of the first resistor R1 is grounded.

[0012] Furthermore, the first resistor R1 is an adjustable resistor.

[0013] Furthermore, the first end of the second resistor R2 is electrically connected to the second end and the enable control end of the voltage regulator unit, and the second end of the second resistor R2 is grounded.

[0014] Furthermore, the power supply is a DC power supply, and the voltage conversion unit is a DC voltage conversion circuit.

[0015] Secondly, this utility model provides an HDMI interface, including the HDMI interface backflow prevention circuit described in any of the above embodiments.

[0016] Compared with existing technologies, the beneficial effects of the HDMI interface provided by this utility model are as follows: By setting a voltage regulator unit and a current limiting chip U1 in the anti-backflow circuit of the HDMI interface, when the power is not turned on or the power is lost, if the HDMI output port is mistakenly connected to an external HDMI power output, the voltage regulator unit loses power, and the enable control terminal of the current limiting chip U1 is connected to ground. The enable control terminal changes from a high level to a low level, and the current limiting chip U1 can shut off the current output and input, so that the external HDMI power cannot reach the power circuit of this device through the current limiting chip U1, thus preventing the device from malfunctioning. Therefore, this utility model provides a hardware architecture that helps to prevent current from flowing backward into the unpowered power circuit of the device, reducing the failure rate of the device. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a module for an HDMI interface anti-backflow circuit according to an embodiment of the present invention; Figure 2 This is a circuit diagram of an HDMI interface anti-backflow circuit provided in one embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0021] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] See Figures 1 to 2 , Figure 1 This diagram illustrates a module schematic of an HDMI interface anti-backflow circuit according to an embodiment of the present invention. Figure 2 The diagram shows a circuit diagram of an HDMI interface anti-backflow circuit according to an embodiment of the present invention.

[0024] refer to Figure 1 This utility model provides an HDMI interface backflow prevention circuit, including a power supply and a voltage conversion unit. The input terminal of the voltage conversion unit is electrically connected to the power supply, and the output terminal of the voltage conversion unit is used to output a low DC voltage. The circuit also includes: A voltage regulator unit, wherein the first terminal of the voltage regulator unit is electrically connected to the power supply and the input terminal of the voltage conversion unit; A current limiting chip U1, the enable control terminal of which is electrically connected to the second terminal of the voltage regulator unit, and the input terminal of the current limiting chip U1 is connected to the output terminal of the voltage conversion unit; An HDMI output port is electrically connected to the output terminal of the current limiting chip U1.

[0025] This embodiment incorporates a voltage regulator unit and a current limiting chip U1 in the HDMI interface backflow prevention circuit. When the power is off or the power supply is lost, if the HDMI output port is mistakenly connected to an external HDMI power supply, the voltage regulator unit loses power, and the enable control terminal of the current limiting chip U1 is grounded. This causes the enable control terminal to change from a high level to a low level, allowing the current limiting chip U1 to shut off both current output and input. This prevents external HDMI power from reaching the device's power circuit through the current limiting chip U1, thus avoiding device malfunction. Therefore, this invention provides a hardware architecture that helps prevent reverse current from flowing into the device's unpowered power circuit, reducing the device's malfunction rate.

[0026] Preferably, refer to Figure 1 The current limiting chip U1 includes: The first diode D1, the anode of the first diode D1 is electrically connected to the output terminal of the voltage conversion unit; The second diode D2 has its cathode electrically connected to the cathode of the first diode D1, and its anode electrically connected to the HDMI output port.

[0027] In this embodiment, by integrating two diodes with opposite directions inside the current limiting chip U1, the external HDMI power supply cannot reach the power circuit of this device through the current limiting chip U1, thus preventing the device from malfunctioning.

[0028] Preferably, refer to Figure 1 The current limiting chip U1 also includes: A switching unit, wherein a first terminal of the switching unit is electrically connected to the anode of the first diode D1, and a second terminal of the switching unit is electrically connected to the anode of the second diode D2; The control unit is electrically connected to the controlled terminal of the switch unit, and the first terminal of the control unit serves as the enable control terminal of the current limiting chip U1.

[0029] In this embodiment, the first terminal of the control unit can be used as the enable control terminal of the current limiting chip U1. When the high level changes to the low level, the control terminal of the control unit outputs a control signal to the controlled terminal of the switching unit, thereby controlling the switching unit to open. As a result, external HDMI power cannot reach the power circuit of this device through the current limiting chip U1, thus preventing the device from malfunctioning. Preferably, refer to Figure 2 The switching unit may be a first MOS transistor Q1, and the first diode D1 and the second diode D2 are integrated between the source and drain of the first MOS transistor Q1. The gate of the first MOS transistor Q1 serves as the controlled terminal of the switching unit.

[0030] Preferably, refer to Figure 2 The voltage regulator unit may include a Zener diode D3, with the anode of the Zener diode D3 serving as the second terminal of the voltage regulator unit and the cathode of the Zener diode D3 serving as the first terminal of the voltage regulator unit.

[0031] Preferably, refer to Figure 1 The first end of the first resistor R1 is electrically connected to the ISET pin of the current limiting chip U1, and the second end of the first resistor R1 is grounded.

[0032] In this embodiment, the ISET pin of the current limiting chip U1 is used to set the current limiting threshold. It is configured by connecting the first resistor R1 to ground, and the maximum output current (e.g., 0.1V / 1Ω=100mA) can be calculated according to the formula. Therefore, by changing the resistance value of the first resistor, the maximum value of the output current at the output terminal of the current limiting chip U1 can be adjusted.

[0033] In one embodiment, the first resistor R1 can be an adjustable resistor. This allows for changing the resistance value of the first resistor, thereby adjusting the maximum value of the output current at the output terminal of the current limiting chip U1.

[0034] Preferably, refer to Figure 1 The first end of the second resistor R2 is electrically connected to the second end and the enable control end of the voltage regulator unit, and the second end of the second resistor R2 is grounded.

[0035] In one embodiment, the power supply is a DC power supply, and the voltage conversion unit is a DC voltage conversion circuit.

[0036] This utility model embodiment also provides an HDMI interface, including the HDMI interface backflow prevention circuit described in any of the above embodiments.

[0037] This embodiment incorporates a voltage regulator unit and a current limiting chip U1 in the HDMI interface backflow prevention circuit. When the power is off or the power supply is lost, if the HDMI output port is mistakenly connected to an external HDMI power supply, the voltage regulator unit loses power, and the enable control terminal of the current limiting chip U1 is grounded. This causes the enable control terminal to change from a high level to a low level, allowing the current limiting chip U1 to shut off both current output and input. This prevents external HDMI power from reaching the device's power circuit through the current limiting chip U1, thus avoiding device malfunction. Therefore, this invention provides a hardware architecture that helps prevent reverse current from flowing into the device's unpowered power circuit, reducing the device's malfunction rate.

[0038] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0039] The specific embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An HDMI interface anti-backflow circuit, comprising a power supply and a voltage conversion unit, an input end of the voltage conversion unit being electrically connected with the power supply, and an output end of the voltage conversion unit being used for outputting a direct-current low voltage, characterized in that, The circuit also includes: A voltage regulator unit, wherein the first terminal of the voltage regulator unit is electrically connected to the input terminal of the power supply and the voltage conversion unit, and the second terminal of the voltage regulator unit is grounded; A current limiting chip U1, the enable control terminal of which is electrically connected to the second terminal of the voltage regulator unit, and the input terminal of the current limiting chip U1 is connected to the output terminal of the voltage conversion unit; An HDMI output port is electrically connected to the output terminal of the current limiting chip U1.

2. The HDMI interface backflow prevention circuit of claim 1, wherein: The current limiting chip U1 includes: The first diode D1, the anode of the first diode D1 is electrically connected to the output terminal of the voltage conversion unit; The second diode D2 has its cathode electrically connected to the cathode of the first diode D1, and its anode electrically connected to the HDMI output port.

3. The HDMI interface backflow prevention circuit according to claim 2, characterized in that: The current limiting chip U1 also includes: A switching unit, wherein a first terminal of the switching unit is electrically connected to the anode of the first diode D1, and a second terminal of the switching unit is electrically connected to the anode of the second diode D2; The control unit is electrically connected to the controlled terminal of the switch unit, and the first terminal of the control unit serves as the enable control terminal of the current limiting chip U1.

4. The HDMI interface backflow prevention circuit of claim 3, wherein: The switching unit is a first MOSFET Q1, and the first diode D1 and the second diode D2 are integrated between the source and drain of the first MOSFET Q1. The gate of the first MOSFET Q1 serves as the controlled terminal of the switching unit.

5. The HDMI interface backflow prevention circuit of claim 1, wherein: The voltage regulator unit includes a Zener diode D3, with the anode of the Zener diode D3 serving as the second terminal of the voltage regulator unit and the cathode of the Zener diode D3 serving as the first terminal of the voltage regulator unit.

6. The HDMI interface backflow prevention circuit of claim 1, wherein: It also includes a first resistor R1, the first end of which is electrically connected to the ISET pin of the current limiting chip U1, and the second end of the first resistor R1 is grounded.

7. The HDMI interface backflow prevention circuit of claim 6, wherein: The first resistor R1 is an adjustable resistor.

8. The HDMI interface backflow prevention circuit of claim 1, wherein: It also includes a second resistor R2, the first end of which is electrically connected to the second end and the enable control end of the voltage regulator unit, and the second end of the second resistor R2 is grounded.

9. The HDMI interface backflow prevention circuit of claim 1, wherein: The power supply is a DC power supply, and the voltage conversion unit is a DC voltage conversion circuit.

10. An HDMI interface, characterized by: Includes the HDMI interface backflow prevention circuit as described in any one of claims 1-9.

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