Ground path switching circuit and electronic device

Abstract

The utility model discloses a kind of grounding path switching circuit and electronic equipment, including switch, mainboard and small board, wherein, the public end of switch is connected with the earphone seat in the small board, the first selection end is electrically connected with the first grounding point, the second selection end is electrically connected with the second grounding point;The control end is connected with the control unit in the mainboard. By setting ground point on mainboard and small board respectively, ground path is switched according to different working scene using switch, it can be switched to mainboard in 2G PA working time electronic equipment grounding point, effectively suppress TDD noise interference, it can be switched to small board in non-2G communication scene, shorten ground line length, reduce ground impedance, reduce the crosstalk problem between earphone of electronic equipment, optimize ear return howl and music playing effect. In addition, the grounding path switching circuit does not need to increase additional complex circuit or expensive component, and the cost is low.

Description

Technical Field

[0001] This utility model relates to the field of audio processing technology, and in particular to a grounding path switching circuit and electronic device. Background Technology

[0002] In current mobile terminal devices, the 3.5mm analog electronic device interface is still widely used due to its versatility and multi-functionality (such as calls, music playback, and real-time earphone monitoring). In order to suppress the interference of time division duplex (TDD) noise generated during the operation of radio frequency circuits on audio signals, a common approach in the prior art is to place the grounding point of the electronic device socket near the audio codec on the motherboard, sharing the grounding point with the audio circuit.

[0003] However, the above solution has introduced new technical problems in practice. Since electronic device sockets are typically located on a small board far from the motherboard, their grounding wires must travel a long path to connect to the motherboard, resulting in significant grounding impedance. Higher grounding impedance degrades audio quality, specifically by increasing signal crosstalk between the earpiece and microphone, and between the left and right channels. This can lead to feedback when using the in-ear monitoring function in karaoke software, or reduce stereo sound quality when playing music, severely impacting the user experience. Utility Model Content

[0004] The purpose of this invention is to provide a grounding path switching circuit and electronic device to reduce crosstalk between the earpieces of electronic devices and optimize in-ear feedback and music playback effects.

[0005] This utility model discloses a grounding path switching circuit, including:

[0006] The motherboard, including the first ground point;

[0007] Small board, including the second grounding point;

[0008] The switch includes a common terminal, a first selection terminal, a second selection terminal, and a control terminal; the common terminal is connected to the headphone jack in the small board, the first selection terminal is electrically connected to the first grounding point, the second selection terminal is electrically connected to the second grounding point, and the control terminal is connected to the control unit in the main board.

[0009] Furthermore, the control unit is a CPU.

[0010] Furthermore, the first input / output terminal of the CPU is connected to the control terminal of the switching switch.

[0011] Furthermore, the motherboard also includes an audio codec;

[0012] The grounding terminal of the audio codec is connected to the first grounding point.

[0013] Furthermore, the switching switch is located between the headphone jack and the audio codec.

[0014] Furthermore, the switching switch is a single-pole double-throw switch.

[0015] On the other hand, this utility model provides an electronic device including the above-mentioned grounding path switching circuit.

[0016] Furthermore, the switching switch and the antenna within the electronic device are distributed on different sides of the small board.

[0017] Furthermore, the switching switch is located outside the antenna clearance area of ​​the electronic device.

[0018] Compared with the prior art, the present invention has at least the following technical effects:

[0019] This invention sets ground points on both the main board and the sub-board, and uses a switch to intelligently switch the grounding path according to different operating scenarios. When the 2G PA is working, the grounding point of the electronic device is switched to the main board, effectively suppressing TDD noise interference. In non-2G call scenarios, the grounding point is switched to the sub-board, significantly shortening the grounding trace length and reducing ground impedance. This significantly reduces crosstalk between earpieces in electronic devices and optimizes in-ear feedback and music playback during karaoke. Furthermore, this grounding path switching circuit requires no additional complex circuits or expensive components, resulting in a simple structure and low cost. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the grounding path switching circuit in one embodiment of the present invention. Detailed Implementation

[0021] The following detailed description, with reference to schematic diagrams, illustrates a grounding path switching circuit and electronic device of this utility model, showing preferred embodiments of the present invention. It should be noted that the following description is intended to enable those skilled in the art to understand and implement this utility model, and is for illustrative purposes rather than limiting its scope. Those skilled in the art should understand that, based on the teachings of this specification, various modifications, equivalent substitutions, or improvements can be made to the described specific embodiments without departing from the core spirit and principles of this utility model. For example, technical features from different embodiments can be cross-combined to form new technical solutions. As long as no technical contradictions arise, these variations and combinations should fall within the scope of protection claimed by this utility model.

[0022] The present invention will be described more specifically by way of example with reference to the accompanying drawings in the following paragraphs. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0023] Example 1

[0024] Please refer to Figure 1 This embodiment discloses a grounding path switching circuit, including:

[0025] Motherboard 2, including the first grounding point 9.

[0026] Small board 3, including the second grounding point 10.

[0027] The switch 8 includes a common terminal 11, a first selection terminal 13, a second selection terminal 12, and a control terminal 14; the common terminal 11 is connected to the headphone jack 7 in the small board 3, the first selection terminal 13 is electrically connected to the first grounding point 9, the second selection terminal 12 is electrically connected to the second grounding point 10; and the control terminal 14 is connected to the control unit 5 in the main board 2.

[0028] In this embodiment, by setting ground points on the main board 2 and the small board 3 respectively, and using a switching switch 8 to intelligently switch the grounding path according to different working scenarios, the grounding point of the electronic device can be switched to the main board 2 when the 2G PA is working, effectively suppressing TDD noise interference. Conversely, in non-2G call scenarios, the grounding point can be switched to the small board 3, significantly shortening the grounding trace length and reducing ground impedance. This significantly reduces crosstalk problems between the earpieces of the electronic devices, optimizing the feedback and music playback effects during karaoke. Furthermore, this grounding path switching circuit does not require additional complex circuits or expensive components, resulting in a simple structure and low cost.

[0029] Specifically, when the RF 2G power amplifier (PA) is not working (e.g., during music playback, karaoke software use, VoLTE / VoWiFi calls, etc.), the control unit 5 outputs a control signal to the switch 8, connecting its common terminal 11 to the second selection terminal 12. At this time, the grounding point of the earphone jack 7 is directly connected to the second grounding point 10 on the small board 3. Since the earphone jack 7 and the second grounding point 10 are both located on the same small board 3, this grounding path is extremely short, exhibiting very low ground impedance. The significant technical effect is that it reduces signal crosstalk between the left and right earpieces of the electronic device, improves channel separation and sound field positioning accuracy during stereo music playback, and significantly reduces crosstalk between the microphone signal and the earpiece signal, thereby effectively suppressing or eliminating the feedback problem caused by delayed playback when using karaoke software.

[0030] When the RF 2G power amplifier (PA) is operating (i.e., during a 2G network call), the 2G PA generates strong time-division duplex (TDD) noise, which can easily couple to the audio circuitry through the grounding path, creating noise in the electronic device. To address this issue, the control unit 5 outputs another control signal to the switch 8, connecting its common terminal 11 to the first selection terminal 13. At this time, the grounding point of the earphone jack 7 is switched to the first grounding point 9 on the motherboard 2. This design effectively optimizes the suppression of TDD noise by changing the structure of the grounding loop. Meanwhile, since users typically do not use music playback or karaoke earphone monitoring functions during 2G calls, the crosstalk and howling problems that needed to be addressed in the first scenario are not prominent in this scenario.

[0031] With the above dual-mode grounding strategy, this embodiment does not require the addition of complex filtering circuits or expensive shielding components. It achieves optimal performance in different application scenarios with just a simple switching switch 8, and has the advantages of simple structure and low cost.

[0032] Furthermore, the control unit 5 is a CPU.

[0033] In this embodiment, the CPU establishes a connection with the control terminal 14 of the switching switch 8 through its input / output pins, and can dynamically switch the grounding path according to the working state, thereby optimizing the high-frequency signal circuit.

[0034] Specifically, when headphones are plugged into an electronic device, the CPU detects the insertion status of the headphone jack 7 and automatically selects the optimal grounding path based on the current operating mode. In 2G call scenarios (where TDD noise suppression is required), the CPU sends a high-level control signal to the switch 8 via GPIO1, making the common terminal 11 of the switch 8 conduct with the first selection terminal, thereby connecting the ground of the headphone jack 7 to the first grounding point 9 on the motherboard 2. In non-2G call scenarios such as music playback and karaoke, the CPU sends a low-level control signal, making the common terminal 11 of the switch 8 conduct with the second selection terminal, switching the grounding path of the headphone jack 7 to the second grounding point 10 on the small board 3, reducing ground impedance and crosstalk by shortening the grounding path length.

[0035] As can be seen, this embodiment can effectively solve the problem of impedance increase caused by long-distance grounding wires, eliminate signal crosstalk between microphone and earpiece in karaoke in-ear monitoring scenarios, and reduce the occurrence of howling to a negligible level; when playing stereo music, the separation of left and right channels is improved, and the sound field positioning accuracy is significantly improved.

[0036] Furthermore, the first input / output terminal GPIO1 of the CPU is connected to the control terminal 14 of the switching switch 8.

[0037] Specifically, when the CPU detects that an electronic device is inserted, its first input / output terminal GPIO1 generates a specific level signal and transmits it to the control terminal 14 of the switch 8. This signal triggers the internal contacts of the switch 8 to switch, so that the common terminal 11 of the headphone jack 7 is selectively connected to the ground point of the main board 2 or the small board 3.

[0038] Furthermore, the motherboard 2 also includes an audio codec 6; the grounding terminal of the audio codec 6 is connected to the first grounding point 9.

[0039] In this embodiment, the ground terminal of the audio codec 6 forms a low-impedance loop with the first ground point 9 of the motherboard 2 through a copper foil trace. The first ground point 9 refers to the metallized via area on the motherboard 2 used to collect circuit noise. Specifically, it can be implemented using a gold-plated via array with a diameter of 0.3mm. By reducing the impedance of the ground loop, high-frequency interference is suppressed from coupling to the audio signal path.

[0040] In one specific embodiment, the switching switch 8 is a single-pole double-throw switch.

[0041] Furthermore, the switching switch 8 is disposed between the headphone jack 7 and the audio codec 6.

[0042] In this embodiment, the switching switch 8 is positioned between the headphone jack 7 and the audio codec 6, which has the following advantages: First, it allows the switching switch 8 to be physically close to the headphone jack 7. When switching to grounding the small board 3, its connection path (i.e., from the common terminal 11 to the second selection terminal 12) is physically minimized, thereby maximizing the effect of low-impedance grounding. Second, when switching to grounding the main board 2 is required, this central position also facilitates the unified planning and routing of the traces from the switch (first selection terminal 13) to the first grounding point 9 of the main board 2 and the audio signal lines from the headphone jack 7 to the audio codec 6. This is beneficial for EMC design such as differential routing or common ground shielding, and further suppresses crosstalk during signal transmission.

[0043] Example 2

[0044] Based on the same inventive concept, this embodiment discloses an electronic device, specifically including the grounding path switching circuit disclosed in Embodiment 1.

[0045] The electronic device mentioned above is primarily an earphone, which includes, but is not limited to: over-ear headphones that completely cover the ear to provide good physical noise isolation; on-ear headphones with the sound unit pressed against the ear; in-ear headphones that penetrate deep into the ear canal to obtain optimal low-frequency response and passive noise cancellation; true wireless headphones with completely separate left and right ear units and no physical cable connection; neckband headphones that connect the left and right units via a neckband; or bone conduction headphones that transmit sound using skull vibrations. Of course, those skilled in the art can choose different headphones according to the actual situation.

[0046] Furthermore, the switching switch 8 is located outside the antenna clearance area of ​​the earphone.

[0047] In this embodiment, this layout aims to physically protect the antenna radiation area, preventing antenna detuning, efficiency reduction, and pattern distortion caused by components or grounding copper being too close together, thereby ensuring the stability and efficiency of wireless communication.

[0048] Furthermore, as a preferred embodiment, the switching switch 8 is positioned on different layers or sides of the printed circuit board, corresponding to the antenna. For example, when the antenna is located on the top layer of the printed circuit board, the switching switch 8 is preferably located on the bottom layer. This spatial isolation layout can further reduce electromagnetic interference to the antenna during switch circuit operation, thereby improving the sensitivity of the RF receiving link.

[0049] Furthermore, to ensure the purity of the audio signal, the grounding point is located in the vicinity of the grounding pin of the audio codec 6 and is directly electrically connected to a separate audio main ground plane of the motherboard 2 via a grounding via. This design provides a stable and low-impedance reference ground for the audio signal processing core and fundamentally isolates the path of noise from other digital circuits through ground plane crosstalk to the audio system, which is the basis for achieving high-fidelity audio output.

[0050] Furthermore, to improve the signal integrity of the audio output interface, both the switch 8 and the grounding point 10 are positioned as close as possible to the grounding pin of the headphone jack. This arrangement aims to minimize the loop length of the audio signal return current, thereby significantly reducing the impedance of the grounding loop, effectively suppressing ground loop effects that may introduce noise, and ensuring the clarity of the audio signal ultimately heard by the user.

[0051] It is understandable that the technical effects that the grounding path switching circuit in Embodiment 1 can achieve can also be achieved by the headphones disclosed in this embodiment, so they will not be described again here.

[0052] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A grounding path switching circuit, characterized in that, include: The motherboard, including the first ground point; Small board, including the second grounding point; The switch includes a common terminal, a first selection terminal, a second selection terminal, and a control terminal; the common terminal is connected to the headphone jack in the small board, the first selection terminal is electrically connected to the first grounding point, the second selection terminal is electrically connected to the second grounding point, and the control terminal is connected to the control unit in the main board.

2. The grounding path switching circuit as described in claim 1, characterized in that, The control unit is a CPU.

3. The grounding path switching circuit as described in claim 2, characterized in that, The first input / output terminal of the CPU is connected to the control terminal of the switching switch.

4. The grounding path switching circuit as described in claim 1, 2, or 3, characterized in that, The motherboard also includes an audio codec; The grounding terminal of the audio codec is connected to the first grounding point.

5. The grounding path switching circuit as described in claim 4, characterized in that, The switch is located between the headphone jack and the audio codec.

6. The grounding path switching circuit as described in claim 5, characterized in that, The switching switch is a single-pole double-throw switch.

7. An electronic device, characterized in that, Includes the grounding path switching circuit as described in any one of claims 1-6.

8. The electronic device as claimed in claim 7, characterized in that, The switching switch and the antenna inside the electronic device are distributed on different sides of the small board.

9. The electronic device as claimed in claim 8, characterized in that, The switching switch is located outside the antenna clearance area of ​​the electronic device.

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