An HDMI filter circuit board device for a shielded box

Abstract

The utility model discloses a HDMI filter circuit board device for shielding box belongs to electronic circuit field, a HDMI filter circuit board device for shielding box, including printed circuit board, the front of printed circuit board is provided with differential mode filter circuit, the front of printed circuit board is provided with a pair of common mode filter circuit, and a pair of common mode filter circuit is located at the both sides of differential mode filter circuit respectively, the front of printed circuit board is provided with a pair of HDMI interface, and a pair of HDMI interface is located at the both ends of printed circuit board front, the outside of printed circuit board is provided with metal shielding layer, and the edge of metal shielding layer outer wall is evenly provided with ground via, and differential mode filter circuit is in parallel connected by hollow inductance and through -hole capacitor group, it can realize the transmission of all kinds of interference that HDMI signal is received in shielding box when, improve the anti -jamming capability of signal, guarantee the stable, high -quality transmission of high -definition audio and video signal.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuits, and more specifically, to an HDMI filter circuit board device for a shielded enclosure. Background Technology

[0002] In the testing and application of modern electronic equipment, shielded enclosures are widely used to isolate external electromagnetic interference and ensure the normal operation of internal electronic equipment. HDMI interfaces, as a common interface for transmitting high-definition audio and video signals, are increasingly used within shielded enclosures. However, due to the complex electromagnetic environment inside the shielded enclosure and the high-speed transmission characteristics of HDMI signals, HDMI signals are highly susceptible to interference during transmission, leading to problems such as signal distortion, image stuttering, and audio noise.

[0003] Based on the above, the inventors have discovered that while some filtering solutions for HDMI signals exist on the market, they still exhibit numerous shortcomings when applied to shielded enclosure scenarios. For example, some filtering circuit designs are too simple, only able to suppress interference at specific frequencies to a limited extent, failing to effectively cope with complex and ever-changing electromagnetic interference environments; some filters have poor compatibility with shielded enclosures, are inconvenient to install, and cannot fully utilize the shielding characteristics of the enclosure to synergistically improve the filtering effect; and some solutions cause a certain degree of attenuation to the power and integrity of the HDMI signal itself during the filtering process, affecting the signal transmission quality. Therefore, developing a high-performance HDMI filter circuit board device specifically for shielded enclosure applications is of significant practical importance. Thus, in view of this, the inventors have researched and improved the existing structure to provide an HDMI filter circuit board device for shielded enclosures, aiming to achieve a more practical and valuable purpose. Utility Model Content

[0004] 1. Technical problems to be solved

[0005] To address the problems existing in the prior art, the purpose of this utility model is to provide an HDMI filter circuit board device for shielded enclosures. This device can effectively filter out various interferences encountered by HDMI signals during transmission within the shielded enclosure, improving the signal's anti-interference capability and ensuring stable, high-quality transmission of high-definition audio and video signals. Simultaneously, the device should have good compatibility with shielded enclosures, facilitating installation and use to meet the needs of practical application scenarios.

[0006] 2. Technical Solution

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] An HDMI filter circuit board device for a shielded enclosure includes a printed circuit board. A differential-mode filter circuit is disposed on the front side of the printed circuit board. A pair of common-mode filter circuits are disposed on the front side of the printed circuit board, with the pair of common-mode filter circuits located on both sides of the differential-mode filter circuit. A pair of HDMI interfaces are disposed on the front side of the printed circuit board, with the pair of HDMI interfaces located at both ends of the front side of the printed circuit board. A metal shielding layer is disposed on the outside of the printed circuit board, and grounding vias are uniformly disposed along the edge of the outer wall of the metal shielding layer.

[0009] Furthermore, the differential mode filter circuit is composed of a hollow inductor and a feedthrough capacitor group connected in parallel, and both the hollow inductor and the feedthrough capacitor group of the differential mode filter circuit are fixedly soldered to the printed circuit board.

[0010] Furthermore, each of the aforementioned common-mode filter circuits is composed of a common-mode inductor, and the core material of the common-mode inductor is manganese zinc ferrite.

[0011] Furthermore, the pair of HDMI interfaces are electrically connected to the circuitry inside the printed circuit board via metal pins, and the HDMI interfaces are made of metal.

[0012] Furthermore, the metal shielding layer covers the outside of the printed circuit board and the HDMI interface, and the metal shielding layer is connected to the ground layer of the printed circuit board through multiple grounding vias.

[0013] 3. Beneficial Effects

[0014] Compared with existing technologies, the advantages of this utility model are:

[0015] This solution employs a multi-stage cascaded approach, combining differential-mode and common-mode filtering circuits. This multi-stage filtering structure progressively filters interference across different frequency bands, enhancing the suppression of complex electromagnetic interference. A four-stage common-mode filter and a four-stage differential-mode filter can be configured. Through proper wiring and impedance matching, the integrity and stability of the signal during the cascading process are ensured, thereby improving the signal's anti-interference capability and guaranteeing stable, high-quality transmission of high-definition audio and video signals. Furthermore, the device should have good compatibility with shielded enclosures for easy installation and use, meeting the needs of practical application scenarios. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0017] Figure 2 This is a three-dimensional front view of the printed circuit board structure of this utility model;

[0018] Figure 3This is a three-dimensional rear view schematic diagram of the printed circuit board structure of this utility model.

[0019] Explanation of the labels in the diagram:

[0020] 1. Printed circuit board; 2. Differential mode filter circuit; 3. Common mode filter circuit; 4. HDMI interface; 5. Metal shielding layer; 6. Grounding via. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model. Example

[0022] Please see Figures 1-3 An HDMI filter circuit board device for a shielded enclosure includes a printed circuit board 1. A differential-mode filter circuit 2 and a pair of common-mode filter circuits 3 are disposed on the front side of the printed circuit board 1, with the common-mode filter circuits 3 located on opposite sides of the differential-mode filter circuit 2. A pair of HDMI interfaces 4 are disposed on the front side of the printed circuit board 1, located at both ends of the front side. A metal shielding layer 5 is disposed on the exterior of the printed circuit board 1, and grounding vias 6 are evenly distributed along the edge of the outer wall of the metal shielding layer 5. The printed circuit board 1 of this device uses FR-4 or Rogers board materials with excellent high-frequency performance as the substrate. FR-4 board materials have good electrical and mechanical properties, relatively low cost, and are suitable for general applications. For applications requiring higher high-frequency performance, Rogers board materials, such as RO3003 or RO3010, can be selected. These boards have low dielectric constants and dielectric losses, effectively reducing attenuation and distortion during signal transmission, ensuring high-speed, high-quality transmission of HDMI signals. HDMI interface 4 uses a high-quality HDMI standard interface to ensure signal transmission stability and compatibility. The device primarily employs a cascaded multi-stage common-mode filter circuit 3 and differential-mode filter circuit 2. This multi-stage filtering structure progressively filters interference from different frequency bands, enhancing the suppression of complex electromagnetic interference. A four-stage common-mode filter circuit 3 and a four-stage differential-mode filter circuit 2 can be configured. Through reasonable wiring and impedance matching between each filter circuit, the integrity and stability of the signal during the cascading process are ensured.

[0023] See Figure 1The differential mode filter circuit 2 is composed of a hollow inductor and a feedthrough capacitor group connected in parallel. Both the hollow inductor and the feedthrough capacitor group are fixedly soldered to the printed circuit board 1. This differential mode filter circuit 2, composed of inductors and feedthrough capacitors, is used to filter out differential mode interference in HDMI signals. The differential mode inductor is either a hollow inductor or an inductor wound on a low-permeability magnetic core to avoid excessive influence on normal signals. The feedthrough capacitor and inductor are connected in parallel to form an LC filter network. By adjusting the parameters of the inductor and capacitor, the resonant frequency of the filter circuit is matched with the frequency of the differential mode interference to be filtered out, thereby effectively suppressing differential mode interference.

[0024] See Figure 1 The common-mode filter circuit 3 consists of a common-mode inductor, and the core material of the common-mode inductor is manganese zinc ferrite. The common-mode inductor of the common-mode filter circuit 3 is used to suppress common-mode interference during HDMI signal transmission. The common-mode inductor uses a high-permeability core material, such as manganese zinc ferrite, to improve the inductance value and filtering effect. Manganese zinc ferrite material is suitable for interference suppression above 1MHz; metallic magnetic materials are suitable for low-frequency interference suppression in the 10kHz to 100kHz range.

[0025] See Figure 1 , Figure 2A pair of HDMI interfaces 4 are electrically connected to the internal circuitry of the printed circuit board 1 via metal pins. The HDMI interfaces 4 are made of metal. Each signal pin of the HDMI interface 4 is electrically connected to the corresponding input terminal of the filtering circuit via copper foil traces on the printed circuit board 1 to ensure continuous signal transmission. The output terminals of the differential-mode filtering circuit 2 and the common-mode filtering circuit 3 are connected to the input terminal of the signal isolation circuit. The isolated signal is then connected to the HDMI signal receiving device inside the shielded enclosure via copper foil traces. During the electrical connection process, attention is paid to the width, length, and layout of the copper foil traces to reduce the resistance, inductance, and capacitance of the traces, thereby reducing signal loss and interference during transmission. The metal shielding layer 5 covers the outside of the printed circuit board 1 and the HDMI interfaces 4. The metal shielding layer 5 is connected to the ground layer of the printed circuit board 1 via multiple grounding vias 6. The metal shielding layer 5, made of highly conductive materials such as copper, is attached to the surface of the printed circuit board 1 by chemical plating or physical deposition. The metal shielding layer 5 completely encloses key components such as the differential mode filter circuit 2, the common mode filter circuit 3, and the HDMI interface 4, forming a closed shielding space. This effectively blocks external electromagnetic interference from entering the printed circuit board 1 and prevents signals inside the printed circuit board 1 from leaking outward, thus avoiding interference with other electronic devices inside the shielding box. The metal shielding layer 5 is connected to the grounding layer of the printed circuit board 1 through multiple grounding vias 6, ensuring that the metal shielding layer 5 can promptly introduce the induced interference current to the ground.

[0026] In use: The size and shape of this device are customized according to the reserved installation space inside the shielding box to ensure a tight and stable installation inside the shielding box. The edge of the printed circuit board 1 has exposed copper that directly connects to the outer shell of the shielding box, ensuring the isolation of the shielding box. A multi-layer wiring design is adopted on the surface of the printed circuit board 1, with different functional circuit layers superimposed on each other, saving space and effectively reducing interference between signals. To improve the filtering effect, a multi-stage differential-mode filter circuit 2 and a common-mode filter circuit 3 are cascaded. The multi-stage filtering structure can progressively filter interference in different frequency bands, enhancing the suppression capability against complex electromagnetic interference. A four-stage common-mode filter circuit 3 and a four-stage differential-mode filter circuit 2 can be configured. Reasonable wiring and impedance matching between each stage of the filter circuit ensure the integrity and stability of the signal during the cascading process.

[0027] The above description is merely a preferred embodiment of this utility model; however, the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and its improved concept, should be included within the protection scope of this utility model.

Claims

1. An HDMI filter circuit board device for a shielded enclosure, comprising a printed circuit board (1), characterized in that: The printed circuit board (1) has a differential mode filter circuit (2) on its front side, and a pair of common mode filter circuits (3) on its front side, with the pair of common mode filter circuits (3) located on both sides of the differential mode filter circuit (2). The printed circuit board (1) has a pair of HDMI interfaces (4) on its front side, with the pair of HDMI interfaces (4) located at both ends of the front side of the printed circuit board (1). The printed circuit board (1) has a metal shielding layer (5) on its exterior, with grounding vias (6) evenly distributed along the edge of the outer wall of the metal shielding layer (5).

2. The HDMI filter circuit board device for a shielded enclosure according to claim 1, characterized in that: The differential mode filter circuit (2) is composed of a hollow inductor and a feedthrough capacitor group connected in parallel, and both the hollow inductor and the feedthrough capacitor group of the differential mode filter circuit (2) are fixedly soldered to the printed circuit board (1).

3. The HDMI filter circuit board device for a shielded enclosure according to claim 1, characterized in that: The common-mode filter circuit (3) consists of a common-mode inductor, and the core material of the common-mode inductor is manganese zinc ferrite.

4. The HDMI filter circuit board device for a shielded enclosure according to claim 1, characterized in that: A pair of HDMI interfaces (4) are electrically connected to the circuit inside the printed circuit board (1) via metal pins, and the HDMI interface (4) is made of metal.

5. The HDMI filter circuit board device for a shielded enclosure according to claim 1, characterized in that: The metal shielding layer (5) covers the outside of the printed circuit board (1) and the HDMI interface (4), and the metal shielding layer (5) is connected to the ground layer of the printed circuit board (1) through multiple grounding vias (6).

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