Tuning circuit, circuit board and display equipment mainboard

Abstract

The utility model provides a tuning circuit, a circuit board and a display equipment mainboard, and the tuning circuit comprises a tuning chip which is provided with a radio frequency signal input end and a signal grounding end; the shielding cover shell is arranged outside the tuning chip in a covering manner; and the radio frequency interface is separably arranged outside the shielding case shell, the radio frequency interface is connected with the radio frequency signal input end through a radio frequency wire core, the radio frequency interface is provided with a radio frequency grounding end, and an isolation circuit is connected between the radio frequency grounding end and the signal grounding end. According to the technical scheme, the lightning protection effect can be achieved, and radio frequency signal attenuation is avoided.

Description

Technical Field

[0001] This application relates to the field of printed circuit board (PCB) design, and more particularly to tuning circuits, circuit boards, and motherboards for display devices. Background Technology

[0002] In the television (TV) industry, high-frequency shielding covers are typically used to shield electromagnetic radiation and interference. Traditional TV shielding covers usually connect the radio frequency (RF) interface and the shielding cover plate together to form an integrated shielding cover.

[0003] Within the integrated shielding enclosure, the ground loop of the RF interface coincides with the ground loop of the PCB board. During thunderstorms, the current generated by lightning strikes may be transmitted to the PCB board through the antenna and RF signal lines; excessive current can damage the tuning chip. Therefore, certain isolation measures are required for lightning protection. Utility Model Content

[0004] This application provides a tuning circuit, a circuit board, and a display device motherboard to solve the technical problem of tuning chips being damaged by lightning strike current caused by an integrated shield.

[0005] In a first aspect, a tuning circuit is provided, comprising:

[0006] The tuning chip has an RF signal input terminal and a signal ground terminal;

[0007] A shielding housing, covering the outside of the tuning chip; and

[0008] The radio frequency interface is detachably disposed outside the shield housing. The radio frequency interface is connected to the radio frequency signal input terminal through a radio frequency wire core. The radio frequency interface has a radio frequency ground terminal, and an isolation circuit is connected between the radio frequency ground terminal and the signal ground terminal.

[0009] In this technical solution, the tuning circuit includes a tuning chip, a shielding housing, and an RF interface. The tuning chip has an RF signal input terminal and a signal ground terminal. The shielding housing covers the outside of the tuning chip. The RF interface is detachably disposed outside the shielding housing. The RF interface is connected to the RF signal input terminal via an RF wire core. The RF interface has an RF ground terminal, and an isolation circuit connects the RF ground terminal and the signal ground terminal. Because the shielding housing and the RF interface are separated, and an isolation circuit connects the signal ground terminal of the tuning chip and the RF ground terminal of the RF interface, external RF signal lines can be isolated from the tuning chip, achieving the purpose of lightning protection. In addition, by incorporating the isolation circuit as part of the tuning circuit, external RF signal lines can be connected to the input terminal of the tuning chip through the RF interface and the RF wire core, ensuring the stability of the connection between the external RF signal lines and the tuning chip, thereby ensuring the integrity of RF transmission and avoiding RF signal attenuation.

[0010] In conjunction with the first aspect, in one possible design, the isolation circuit includes multiple isolation capacitors and / or multiple isolation resistors connected in parallel. One end of each isolation capacitor is connected to the signal ground terminal, and the other end of each isolation capacitor is connected to the radio frequency ground terminal. One end of each isolation resistor is connected to the signal ground terminal, and the other end of each isolation resistor is connected to the radio frequency ground terminal.

[0011] By setting multiple isolation capacitors and / or multiple isolation resistors connected in parallel, with one end of the isolation capacitor and / or isolation resistor connected to the signal ground terminal and the other end of the isolation capacitor and / or isolation resistor connected to the radio frequency ground terminal, the contact area between the isolation circuit and the ground loop can be increased, ensuring the effectiveness of isolation.

[0012] In conjunction with the first aspect, in one possible design, a coupling capacitor is provided inside the shielding housing, and the RF core is connected to the RF signal input terminal through the coupling capacitor.

[0013] By setting a coupling capacitor between the RF core and the RF signal input terminal, the RF signal can be filtered, thereby improving the signal purity and signal quality.

[0014] In conjunction with the first aspect, in one possible design, the shielding housing includes a tripod shielding housing, wherein all three pins of the tripod shielding housing are connected to the signal ground terminal.

[0015] Connecting all pins of the shield housing to the signal ground terminal ensures the contact area between the shield housing and the ground loop, thus guaranteeing safety.

[0016] In conjunction with the first aspect, in one possible design, the connection between the shield housing and the circuit board containing the tuning circuit is a detachable connection.

[0017] The connection between the shielding housing and the circuit board containing the tuning circuit is made detachable, which makes it easy to replace the shielding housing.

[0018] In conjunction with the first aspect, in one possible design, the shielding housing further includes a four-pin shielding housing, three of which are connected to the signal ground terminal, and the other pin of the four-pin shielding housing is connected to the radio frequency ground terminal.

[0019] By setting up a four-pin shield housing, three of the pins of the four-pin shield housing are connected to the signal ground terminal, and the other pin of the four-pin shield housing is connected to the radio frequency ground terminal. The signal ground terminal and the radio frequency ground terminal can be shorted through the shield housing, thus making it suitable for scenarios where lightning isolation is not required.

[0020] In conjunction with the first aspect, in one possible design, the RF interface includes four pins, including an RF input pin, one end of which is connected to the RF core, and the other three pins of the four pins, excluding the RF input pin, are connected to the RF ground terminal.

[0021] Connecting the other three pins of the RF interface to the RF ground terminal can fix the RF interface, thereby ensuring the stability of the connection between the external RF signal line and the tuning chip.

[0022] In a second aspect, a circuit board is provided, including the tuning circuit described in the first aspect.

[0023] Thirdly, a display device motherboard is provided, comprising:

[0024] Motherboard itself;

[0025] A tuning chip is disposed on the motherboard body, and the tuning chip has a radio frequency signal input terminal and a signal ground terminal;

[0026] A shielding housing is installed over the outside of the tuning chip;

[0027] A radio frequency (RF) interface is disposed on the motherboard body and can be detachably disposed outside the shielding housing; the RF interface has an RF ground terminal.

[0028] An isolation circuit is disposed on the main body of the motherboard and located outside the shielding housing; the isolation circuit is connected between the radio frequency ground terminal and the signal ground terminal; and

[0029] The radio frequency (RF) core is disposed on the motherboard body, and a portion of the RF core is located inside the shielding housing. One end of the RF core is connected to the RF interface, and the other end of the RF core is connected to the RF signal input terminal.

[0030] In conjunction with the third aspect, in one possible design, the display device motherboard further includes:

[0031] A coupling capacitor is disposed on the main body of the motherboard and located inside the shielding housing; the other end of the RF core is connected to the RF signal input terminal through the coupling capacitor.

[0032] This application can achieve the following technical effects: By separating the shielding housing from the RF interface and connecting the signal ground terminal of the tuning chip to the RF ground terminal of the RF interface with an isolation circuit, external RF signal lines can be isolated from the tuning chip, thus achieving lightning protection. In addition, by incorporating the isolation circuit as part of the tuning circuit, external RF signal lines can be connected to the input terminal of the tuning chip through the RF interface and RF wire core, ensuring the stability of the connection between the external RF signal lines and the tuning chip, thereby ensuring the integrity of RF transmission and avoiding RF signal attenuation. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of a traditional TV shielding cover;

[0035] Figure 2 This is a schematic diagram of an isolation scheme;

[0036] Figure 3 This is a connection diagram of a tuning circuit provided in an embodiment of this application;

[0037] Figure 4 This is a schematic diagram of the connection of the tripod shield housing provided in the embodiments of this application;

[0038] Figure 5 This is a connection diagram of the four-legged shield housing provided in an embodiment of this application;

[0039] Figure 6 This is a schematic diagram of the connection of the radio frequency interface provided in the embodiments of this application;

[0040] Figure 7This is a schematic diagram of the isolation circuit provided in an embodiment of this application;

[0041] Figure 8 A schematic diagram of the composition structure of a circuit board provided in an embodiment of this application;

[0042] Figure 9 This is a schematic diagram of the appearance of a display device motherboard provided in an embodiment of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0044] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this application do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0045] The technical solution of this application provides a tuning circuit including a shield, which is used to shield electromagnetic radiation and interference.

[0046] Traditional TV shielding such as Figure 1 As shown, the shielding cover is connected to the RF interface to form an integrated shielding cover. Within this integrated shielding cover, the ground loop of the RF interface coincides with the ground loop of the PCB board. During thunderstorms, the current generated by lightning strikes may be transmitted to the PCB board through the antenna and RF signal lines; excessive current can damage the tuning chip. To prevent damage to components from lightning strike currents, such as… Figure 2 As shown, typically an external isolator is connected between the TV board (including an integrated shield) and the RF signal line to isolate the current generated by lightning strikes. Since the external isolator is externally connected to the TV board, poor contact between the external isolator and the TV board can occur, affecting the integrity of RF signal transmission. The inventors of this application, through testing, discovered that the external isolator causes a signal attenuation of 1-2 milliwatts decibels, reducing RF sensitivity. Figure 2The isolation scheme shown achieves lightning protection at the cost of sacrificing some radio frequency performance.

[0047] This application aims to achieve lightning protection without affecting radio frequency (RF) performance. To achieve this, this application provides a novel shielding design that separates the shielding cover from the RF interface into two independent devices. A signal ground terminal and an RF ground terminal are provided in the tuning circuit, and an isolation circuit separates the signal ground terminal from the RF ground terminal. Because the shielding cover and RF interface are separated, and an isolation circuit is provided between the signal ground terminal and the RF ground terminal, the tuning chip is isolated from external RF signal lines. Current generated by lightning strikes will not be transmitted to the tuning chip, thus achieving lightning protection. Since the isolation circuit is integrated into the tuning circuit, making it part of the tuning circuit, poor contact can be avoided, thereby ensuring the integrity of RF transmission and preventing RF signal attenuation, i.e., without affecting RF performance.

[0048] The technical solution of this application is described in detail below.

[0049] See Figure 3 , Figure 3 This is a schematic diagram of the connection of a tuning circuit provided in an embodiment of this application. Figure 3 As shown, the tuning circuit 10 includes a tuning chip 101, a shielding housing 102, and an RF interface 103, wherein:

[0050] The tuning chip 101 has an RF signal input terminal in and a signal ground terminal GND;

[0051] The shield housing 102 covers the outside of the tuning chip 101;

[0052] The radio frequency (RF) interface 103 is detachably disposed outside the shielding housing 102. The RF interface 103 is connected to the RF signal input terminal in via the RF wire core 104. The RF interface 103 has an RF ground terminal RFGND, and an isolation circuit 105 is connected between the RF ground terminal RFGND and the signal ground terminal GND. The RF interface 103 is used to connect external RF signal lines.

[0053] Among them, the tuning chip 101 is a chip used to receive, amplify and process radio frequency signals. The tuning chip 101 can adjust the frequency and impedance of the circuit by adjusting the capacitor and inductor, so as to adjust the power.

[0054] The shield housing 102 refers to the metal cover plate that covers the outside of the tuning chip 101.

[0055] The shielding housing 102 can take many forms. In one possible design, the shielding housing 102 can be as follows: Figure 4As shown, the device includes a tripod shield housing PT1, which has three pins, all of which are connected to the signal ground terminal GND. Connecting all pins of the shield housing to the signal ground terminal ensures sufficient contact area between the shield housing and the ground loop, thus guaranteeing safety.

[0056] The connection between the shield housing 102 and the circuit board containing the tuning circuit can be a fixed connection. For example, the shield housing 102 can be fixed to the circuit board containing the tuning circuit by welding or adhesive bonding.

[0057] The connection between the shielding housing 102 and the circuit board containing the tuning circuit can also be detachable. For example, the shielding housing 102 can be fixed to the circuit board containing the tuning circuit using clips, screws, or other fixing devices; alternatively, the shielding housing 102 can be inserted into a specific slot or interface on the circuit board containing the tuning circuit via a plug-in method. Making the connection between the shielding housing and the circuit board containing the tuning circuit detachable facilitates the replacement of the shielding housing.

[0058] When the connection between the shielding housing 102 and the circuit board containing the tuning circuit is detachable, the shielding housing may include one or more shielding housings. In addition to the aforementioned three-pronged shielding housing PT1, the shielding housing may also include a four-pronged shielding housing CN9, such as... Figure 5 As shown, the four-pin shielding housing CN9 includes four pins. Three of the pins of the four-pin shielding housing CN9 are connected to the signal ground terminal, and the other pin is connected to the radio frequency (RF) ground terminal. By setting up a four-pin shielding housing, connecting three pins of the four-pin shielding housing to the signal ground terminal, and connecting the other pin to the RF ground terminal, the signal ground terminal and the RF ground terminal can be shorted through the shielding housing, thus making it suitable for scenarios where lightning isolation is not required. Of course, all four pins of the four-pin shielding housing CN9 can also be connected to the signal ground terminal. Connecting all four pins of the four-pin shielding housing to the signal ground terminal serves the same function as the three-pin shielding housing described above.

[0059] It is understood that, in addition to the aforementioned three-legged shielding housing PT1 and four-legged shielding housing CN9, the shielding housing 102 may also have other forms of presentation, and this application does not limit them.

[0060] The radio frequency interface 103 refers to the interface that connects radio frequency devices (such as transceivers, antennas, etc.) to the tuning circuit. The radio frequency interface 103 connects the radio frequency devices to the tuning circuit 10 through an external radio frequency signal line.

[0061] In one possible design, such as Figure 6 As shown, the RF interface 103 includes four pins, including an RF input pin. One end of the RF input pin is connected to the RF core 104, and the other end is used to connect to an external RF signal line. The other three pins of the RF interface 103 are connected to the RF ground terminal. Connecting the other three pins of the RF interface to the RF ground terminal can fix the RF interface, thereby ensuring the stability of the connection between the external RF signal line and the tuning chip.

[0062] The isolation circuit 105 refers to a circuit that can isolate the current generated by a lightning strike. The isolation circuit 105 may include multiple isolation capacitors and / or multiple isolation resistors connected in parallel. One end of the isolation capacitor is connected to the signal ground terminal, and the other end of the isolation capacitor is connected to the radio frequency ground terminal. One end of the isolation resistor is connected to the signal ground terminal, and the other end of the isolation resistor is connected to the radio frequency ground terminal.

[0063] In one possible design, such as Figure 7 As shown, the isolation circuit 105 may include 11 capacitors connected in parallel. One end of each capacitor is connected to the signal ground terminal, and the other end of each capacitor is connected to the radio frequency ground terminal. When a lightning strike current occurs, the capacitors will charge and store the lightning strike current, thereby preventing the lightning strike current from damaging the circuit.

[0064] It should be understood that the specific settings of the isolation resistors and isolation capacitors can be configured based on actual needs, and this application does not impose any restrictions on this. By setting multiple isolation capacitors and / or multiple isolation resistors connected in parallel, with one end of the isolation capacitor and / or isolation resistor connected to the RF ground terminal and the other end connected to the signal ground terminal, the contact area between the isolation circuit and the ground loop can be increased, ensuring the effectiveness of isolation.

[0065] In the above technical solution, the tuning circuit includes a tuning chip, a shielding housing, and an RF interface. The tuning chip has an RF signal input terminal and a signal ground terminal. The shielding housing covers the outside of the tuning chip. The RF interface is detachably disposed outside the shielding housing. The RF interface is connected to the RF signal input terminal through an RF wire core. The RF interface has an RF ground terminal, and an isolation circuit is connected between the RF ground terminal and the signal ground terminal. Because the shielding housing and the RF interface are separated, and an isolation circuit is connected between the signal ground terminal of the tuning chip and the RF ground terminal of the RF interface, external RF signal lines can be isolated from the tuning chip, achieving the purpose of lightning protection. In addition, by incorporating the isolation circuit as part of the tuning circuit, external RF signal lines can be connected to the input terminal of the tuning chip through the RF interface and the RF wire core, ensuring the stability of the connection between the external RF signal lines and the tuning chip, thereby ensuring the integrity of RF transmission and avoiding RF signal attenuation.

[0066] In some possible designs, such as Figure 3 As shown, a coupling capacitor 106 is also provided inside the shielding housing 102, and the RF core 104 is connected to the RF signal input terminal in through the coupling capacitor 106. By providing a coupling capacitor between the RF core and the RF signal input terminal, the RF signal can be filtered, thereby improving the signal purity and signal quality of the RF signal.

[0067] The tuning circuit 10 of this application can be applied to a circuit board. See also... Figure 8 , Figure 8 A structural block diagram of a circuit board provided in an embodiment of this application, such as... Figure 8 As shown, circuit board 1 includes tuning circuit 10, and the specific connection relationship of tuning circuit 10 can be referred to the above. Figures 3-7 The corresponding descriptions will not be repeated here.

[0068] The circuit board containing the tuning circuit 10 can be the motherboard of a display device, see [link / reference]. Figure 9 , Figure 9 This is a schematic diagram of the appearance of a display device motherboard provided in an embodiment of this application, such as... Figure 9 As shown, the display device motherboard 2 includes a motherboard body 20 and a tuning circuit 10. The tuning circuit 10 includes:

[0069] The tuning chip 101 is mounted on the motherboard body 20.

[0070] The shield housing 102 covers the outside of the tuning chip 101;

[0071] The radio frequency interface 103 is located on the motherboard body 101;

[0072] An isolation circuit 105 is disposed on the main board body 20 and located outside the shielding housing 103; and

[0073] The radio frequency (RF) core 104 is mounted on the motherboard body 20. A portion of the RF core 104 is located inside the shielding housing 102. One end of the RF core 104 is connected to the RF interface 103, and the other end of the RF core 104 is connected to the RF signal input terminal.

[0074] The tuning circuit 10 also includes a coupling capacitor 106, which is disposed on the main body 20 and located inside the shielding housing 103; the RF core 104 is connected to the RF signal input terminal through the coupling capacitor 106.

[0075] For a detailed description and function of the tuning chip 101, shielding housing 102, RF interface 103, RF fiber core 104, isolation circuit 105, and coupling capacitor 106, please refer to the foregoing. Figures 3-7 The corresponding descriptions will not be repeated here.

[0076] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. A tuning circuit, characterized in that, include: The tuning chip has an RF signal input terminal and a signal ground terminal; A shielding housing is installed over the outside of the tuning chip; as well as The radio frequency interface is detachably disposed outside the shield housing. The radio frequency interface is connected to the radio frequency signal input terminal through a radio frequency wire core. The radio frequency interface has a radio frequency ground terminal, and an isolation circuit is connected between the radio frequency ground terminal and the signal ground terminal.

2. The tuning circuit according to claim 1, characterized in that, The isolation circuit includes multiple isolation capacitors and / or multiple isolation resistors connected in parallel. One end of each isolation capacitor is connected to the signal ground terminal, and the other end of each isolation capacitor is connected to the radio frequency ground terminal. One end of each isolation resistor is connected to the signal ground terminal, and the other end of each isolation resistor is connected to the radio frequency ground terminal.

3. The tuning circuit according to claim 1, characterized in that, A coupling capacitor is provided inside the shielding housing, and the radio frequency core is connected to the radio frequency signal input terminal through the coupling capacitor.

4. The tuning circuit according to any one of claims 1-3, characterized in that, The shielding housing includes a tripod shielding housing, and all three pins of the tripod shielding housing are connected to the signal ground terminal.

5. The tuning circuit according to claim 4, characterized in that, The connection between the shield housing and the circuit board containing the tuning circuit is detachable.

6. The tuning circuit according to claim 5, characterized in that, The shielding housing also includes a four-pin shielding housing, three of which are connected to the signal ground terminal, and the other pin of the four-pin shielding housing is connected to the radio frequency ground terminal.

7. The tuning circuit according to any one of claims 1-3, characterized in that, The radio frequency interface includes four pins, including a radio frequency input pin. One end of the radio frequency input pin is connected to the radio frequency core, and the other three pins are connected to the radio frequency ground terminal.

8. A circuit board, characterized in that, Includes the tuning circuit as described in any one of claims 1-7.

9. A display device motherboard, comprising: Motherboard itself; A tuning chip is disposed on the motherboard body, and the tuning chip has a radio frequency signal input terminal and a signal ground terminal; A shielding housing is installed over the outside of the tuning chip; A radio frequency (RF) interface is disposed on the motherboard body and can be detachably disposed outside the shielding housing; the RF interface has an RF ground terminal. An isolation circuit is disposed on the motherboard body and located outside the shielding housing. The isolation circuit is connected between the radio frequency ground terminal and the signal ground terminal. as well as The radio frequency (RF) core is disposed on the motherboard body, and a portion of the RF core is located inside the shielding housing. One end of the RF core is connected to the RF interface, and the other end of the RF core is connected to the RF signal input terminal.

10. The display device motherboard according to claim 9, characterized in that, The display device motherboard also includes: A coupling capacitor is disposed on the main body of the motherboard and located inside the shielding housing; the other end of the RF core is connected to the RF signal input terminal through the coupling capacitor.

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