An adaptive audio switching circuit and method

Abstract

This invention provides an adaptive audio switching circuit and method. A small board contains first and second switching switches and a first grounding point, both of which are connected to the first grounding point. A main board contains a third switching switch and a second grounding point, with the first and second switching switches connected to the second grounding point via the third switching switch. When the terminal device is in a first operating state and the audio device is connected to the terminal device via a first data line, the first or second switching switch is selected to transmit a grounding signal to the first grounding point based on the connection direction of the first data line. When the terminal device is in a second operating state and the audio device is connected to the terminal device via the first data line, the first or second switching switch is selected to transmit the grounding signal to the second grounding point via the third switching switch, based on the connection direction of the first data line. This can optimize the feedback and music playback effects of karaoke software and improve 2G call quality.

Description

Technical Field

[0001] This invention relates to the field of audio signal processing technology, and in particular to an adaptive audio switching circuit and switching method. Background Technology

[0002] As internal space in smartphones and other mobile devices becomes increasingly limited, the 3.5mm headphone jack is being gradually phased out. The Type-C (Universal Serial Bus) interface, with its high-speed transmission capabilities and reversible plug support, has become a unified interface solution that balances data transmission and analog audio output. Type-C analog headphones are increasingly widely used and can be used for various scenarios such as calls, music playback, and karaoke in-ear monitoring.

[0003] Because the audio signal and baseband signal share the Type-C interface, current technology typically places the Type-C headphone analog switch on the motherboard, with the headphone circuit ground point located near this analog switch or near the audio codec. Figure 1 As shown. The headphone ground trace must extend from the Type-C female connector on the small board to the motherboard ground point. The trace path is relatively long, and the equivalent grounding impedance R x +R ext The voltage is too high. Based on the crosstalk mechanism of headphone circuits, when the output level of a certain channel of the headphone is V, the voltage at the ground pin of the Type-C female headphone connector is (Rx + Rext) / (Rload + Rx + Rext) × V, where Rload is the load impedance, Rx is the equivalent impedance between points A and B, Rext is the equivalent impedance between points B and C, and Rref is the equivalent impedance between point B and HPH_REF (A is the headphone ground pin of the Type-C female connector, B is the intersection of the ref trace and the headphone ground trace, and C is the headphone circuit ground point). V is the audio signal. The voltage at the ground pin of the Type-C female headphone connector is the root cause of crosstalk. The larger Rx and Rext are, the more severe the crosstalk from the earpiece to the microphone and between the left and right channels, leading to problems such as howling in karaoke software and poor music playback.

[0004] Furthermore, when the RF amplifier within the terminal device is operating, its radiated TDD (Time Division Duplex) noise can interfere with nearby headphone circuitry, affecting audio quality. Current technology does not provide a headphone grounding switching solution that can simultaneously achieve low crosstalk and low TDD noise interference.

[0005] Please refer to Figure 2 18 is the earpiece sound outlet, 19 is the main board, 22 is the sub-board, 23 is the microphone sound inlet, 24 is the Type-C female connector, 25 is the speaker sound outlet, and 26 is the antenna. 20 and 21 connect the main board and the sub-board; antenna 26 can transmit or receive radio frequency signals. Figure 2As can be seen, when the headphone circuit ground point is placed near the motherboard switch, the headphone ground line is very long and has high impedance, which will cause crosstalk between the headphone earpiece and the headphone mic, and increase crosstalk between the left and right earpieces, resulting in problems such as howling in the earphone of karaoke software and poor music playback. Summary of the Invention

[0006] This invention provides an adaptive audio switching circuit and switching method to reduce crosstalk between earpieces in electronic devices and optimize in-ear feedback and music playback effects.

[0007] This invention provides an adaptive audio switching circuit, comprising: Small board and motherboard; The small board is equipped with a first switching switch, a second switching switch, and a first grounding point. Both the first switching switch and the second switching switch are connected to the first grounding point. The motherboard is equipped with a third switch and a second grounding point. The first switch and the second switch are connected to the second grounding point through the third switch. When the terminal device is in the first working state and the audio device is connected to the terminal device through the first data line, the first switch or the second switch is selected to transmit the grounding signal to the first grounding point based on the access direction of the first data line. When the terminal device is in the second working state, and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch or the second switch is selected to transmit the grounding signal to the second grounding point through the third switch.

[0008] Furthermore, the small board contains a connector that is electrically connected to the audio equipment.

[0009] Furthermore, the third switching switch includes a first audio and data multiplexing switching switch, a second audio and data multiplexing switching switch, a microphone adaptive switching switch, an induction signal switching switch, a positive auxiliary channel switching switch, a negative auxiliary channel switching switch, and an analog ground switching switch; The first audio and data multiplexing switch is configured to switch between the left channel audio signal and the USB data negative signal. The second audio and data multiplexing switch is configured to switch between the right channel audio signal and the USB data positive signal. The induction signal switching switch is configured to select different signal transmission paths to transmit induction signals based on the interface direction when the audio device is connected to the terminal device. The microphone adaptive switch is configured to select different signal transmission paths to transmit microphone signals based on the interface direction when the audio device is connected to the terminal device. The positive auxiliary channel switch is configured to select different signal transmission paths to transmit the positive auxiliary channel signal based on the interface direction when the audio device is connected to the terminal device. The negative auxiliary channel switch is configured to select different signal transmission paths to transmit the negative auxiliary channel signal based on the interface direction when the audio device is connected to the terminal device. The analog ground switch is configured to select whether to connect the motherboard ground path based on the operating state of the RF amplifier within the terminal device.

[0010] Furthermore, the common terminal of the first switch is connected to the first input port of the connector; the first throw terminal of the first switch is connected to the first ground point; the second throw terminal of the first switch is connected to the first throw terminal of the microphone adaptive switch, and the first throw terminal of the microphone adaptive switch is connected to the first throw terminal of the analog ground switch.

[0011] Furthermore, the common terminal of the second switch is connected to the second input port of the connector; the first throw terminal of the second switch is connected to the first ground point; the second throw terminal of the second switch is connected to the second throw terminal of the microphone adaptive switch, and the second throw terminal of the microphone adaptive switch is connected to the second throw terminal of the analog ground switch.

[0012] Furthermore, when the RF amplifier in the terminal device is powered off, and the audio device is connected to the terminal device via a Type-C data cable, the first switching switch is connected to the first ground point, and the second switching switch is connected to the second throw terminal of the microphone adaptive switching switch. When the RF amplifier in the terminal device is powered off, and the audio device is connected to the terminal device via the reverse insertion of the type-C data cable, the first switch is connected to the first throw terminal of the microphone adaptive switch, and the second switch is connected to the first ground point.

[0013] Furthermore, when the RF amplifier in the terminal device is powered on, and the audio device is connected to the terminal device via the correct type-C data cable, the first switching switch is connected to the first throw terminal of the microphone adaptive switching switch, and the second switching switch is connected to the second throw terminal of the microphone adaptive switching switch; the analog ground switching switch is switched to the first throw terminal, and the first switching switch is grounded through the analog ground switching switch; When the RF amplifier in the terminal device is powered on, and the audio device is connected to the terminal device via the reverse insertion of the type-C data cable, the first switching switch is connected to the first throw terminal of the microphone adaptive switching switch, and the second switching switch is connected to the second throw terminal of the microphone adaptive switching switch; the analog ground switching switch is switched to the second throw terminal, and the second switching switch is grounded through the analog ground switching switch.

[0014] Furthermore, when a non-Type-C data cable is plugged into the terminal device via a Type-C interface, the positive auxiliary channel switch is switched to the first throw terminal and connected to the first switch; the negative auxiliary channel switch is switched to the second throw terminal and connected to the second switch.

[0015] Furthermore, when a non-Type-C data cable is plugged into the terminal device via the Type-C interface in reverse, the positive auxiliary channel switch is switched to the second throw terminal and connected to the second switch; the negative auxiliary channel switch is switched to the first throw terminal and connected to the first switch.

[0016] On the other hand, the present invention also provides an adaptive audio switching method, the method comprising: When the terminal device is in the first working state and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch or the second switch is selected to transmit the grounding signal to the first grounding point set in the small board. When the terminal device is in the second working state and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch or the second switch transmits the grounding signal to the second grounding point set in the motherboard through the third switch.

[0017] Compared with the prior art, the present invention has at least the following technical effects: This invention places a first switching switch and a second switching switch on a small board, and sets a first grounding point near the first and second switches, realizing dynamic switching of the grounding position of the audio switching circuit. When the terminal device is in the first working state, the audio switching circuit is grounded near the small board, the ground trace is extremely short, the equivalent grounding impedance is greatly reduced, and the crosstalk between the earpiece and microphone and between the left and right earpieces is significantly reduced, effectively optimizing the feedback and music playback effects of karaoke software. When the terminal device is in the second working state, the first and second switching switches are switched to the second grounding point on the motherboard through a third switching switch, which can effectively suppress TDD noise interference and improve 2G call quality. At the same time, this invention also performs adaptive switching of the grounding of the first and second switching switches based on the access direction of the data cable: thus realizing adaptive adaptation to both positive and negative insertion methods, reducing the equivalent grounding impedance, and improving the audio output quality. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a portion of the circuit structure in a Type-C analog headphone circuit in the background art; Figure 2 This is a partial wiring diagram of a Type-C analog headphone circuit in the background technology; Figure 3 This is a schematic diagram of the circuit structure of the adaptive audio switching circuit in Embodiment 1 of the present invention; Figure 4 This is a partial wiring diagram of the adaptive audio switching circuit in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the adaptive audio switching method in Embodiment 2 of the present invention. Detailed Implementation

[0019] The following description, in conjunction with schematic diagrams, illustrates an adaptive audio switching circuit and switching method according to the present invention, which represents a preferred embodiment of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0020] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the 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 invention.

[0021] Example 1 Please refer to Figure 3 This embodiment discloses an adaptive audio switching circuit, including: a small board 22 and a main board 19; The small board 22 is provided with a first switching switch 12 and a second switching switch 13 and a first grounding point 16 or 17. The first switching switch 12 and the second switching switch 13 are both connected to the first grounding point 16 or 17. The motherboard 19 is provided with a third switch 4 and a second grounding point 15. The first switch 12 and the second switch 13 are connected to the second grounding point 15 through the third switch 4. When the terminal device is in the first working state and the audio device is connected to the terminal device through the first data line, the first switch 12 or the second switch 13 is selected to transmit the grounding signal to the first grounding point based on the access direction of the first data line. When the terminal device is in the second working state, and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch 12 or the second switch 13 is selected to transmit the grounding signal to the second grounding point 15 through the third switch 4.

[0022] In this embodiment, the first switch 12 and the second switch 13 are respectively disposed on the small board 22, and a first grounding point (16 or 17) is set near the first switch 12 and the second switch 13, thereby realizing the dynamic switching of the grounding position of the audio switching circuit. Please refer to Figure 4 When the terminal device is in its first operating state, the audio switching circuit is grounded near the small board 22 with extremely short ground traces, significantly reducing the equivalent grounding impedance. This significantly reduces crosstalk between the earpiece and microphone, as well as between the left and right earpieces, effectively optimizing the feedback and music playback effects of karaoke software. When the terminal device is in its second operating state, the first switching switch 12 and the second switching switch 13 are switched to the second grounding point 15 on the main board via the third switching switch 4, effectively suppressing TDD noise interference and improving 2G call quality. Furthermore, this invention also adaptively switches based on the access direction of the audio device's interface when connected to the terminal device, thereby achieving adaptive adaptation to both positive and negative insertion methods, reducing the equivalent grounding impedance, and improving audio output quality.

[0023] In this embodiment, the first operating state refers to the RF amplifier in the terminal device being powered down, i.e., the terminal device is in a non-2G call operating scenario, including but not limited to everyday audio usage scenarios such as music playback and karaoke software earphone monitoring; the second operating state refers to the RF amplifier in the terminal device being powered on, i.e., the terminal device is in a 2G network call operating scenario. In the first operating state, the 2G PA is not working and does not generate TDD noise interference. The main performance objective at this time is to reduce grounding impedance and reduce crosstalk. In the second operating state, the RF amplifier is working and will generate stronger TDD noise. The main performance objective at this time is to switch the grounding path to the motherboard 19 to suppress noise interference.

[0024] In this embodiment, the access direction of the first data line refers to the physical insertion orientation of the data line relative to the connector 27 when the data line (first data line) of the audio device is inserted into the connector 27 of the terminal device. Specifically, when the first end of the data line is inserted into the connector 27, it is defined as the first direction (normal insertion); when the second end of the data line is inserted into the connector 27 with the opposite side rotated 180° upwards, it is defined as the second direction (reverse insertion). Since the first data line is a double-sided symmetrical interface, the electrical mapping relationship between each pin of the data line and each pin of the connector 27 is different under different access directions. Therefore, adaptive switching is required to ensure the correctness of signal transmission.

[0025] In this embodiment, the audio device interface is a reversible, symmetrical interface, including a USB Type-C interface. The USB Type-C interface adopts a completely symmetrical physical design with 180° rotational symmetry, allowing users to plug and unplug devices from either direction without needing to distinguish between the front and back.

[0026] In this embodiment, the audio device mainly refers to wired headphones. In a preferred embodiment, the audio device is headphones, which include, but are not limited to: over-ear headphones that can completely cover the auricle to provide good physical noise isolation, on-ear headphones that press the sound unit against the auricle, and in-ear headphones that can penetrate deep into the ear canal to obtain optimal low-frequency response and passive noise cancellation. Of course, those skilled in the art can choose different headphones according to the actual situation.

[0027] Furthermore, the small board 22 is provided with a connector 27, which is electrically connected to the audio device.

[0028] In a specific example, connector 27 is a Type C female connector, embedded on board 22. Its pins are electrically connected to the Type C plug of the audio device to transmit audio signals such as left channel signal (L / LeftChannel), right channel signal (R / Right Channel), microphone signal (MIC / Microphone), and ground signal (GND / Ground). It also supports the transmission of USB data signals and baseband signals.

[0029] Furthermore, the motherboard 19 contains a control module 28 and a third switching switch 4.

[0030] The control module 28 generates control commands based on the interface direction of the audio device when it is connected to the terminal device and the working status of the terminal device; the control commands are input into the third switch 4; the third switch 4 controls the on / off state of the first switch 12 and the second switch 13 based on the control commands.

[0031] For details, please continue to refer to [the website / information]. Figure 3 In this embodiment, the control module 28 includes an application processor 1 (AP) that communicates via I... 2 The C interface (SCL / SDA) communicates with peripherals and issues mode configuration commands, while outputting USB 2.0 differential signals (DP / DN), and uses GPIO (General Purpose Input / Output) pins to realize status detection and control signal interaction.

[0032] Audio Codec 2 is responsible for encoding and decoding audio signals, outputting the left channel audio signal HPL and the right channel audio signal HPR, acquiring the microphone input signal MIC, and detecting the audio device connection status and grounding polarity through the SENSE sensing signal pin.

[0033] The Display Port Controller 3 (DP Controller) provides auxiliary signal channels (AUX+ / AUX-) for display ports, used to transmit display control and configuration signals in DP Alt Mode (display port standby mode) to ensure normal communication with external display devices.

[0034] Furthermore, in this embodiment, the third switching switch 4 includes a first audio and data multiplexing switching switch 5, a second audio and data multiplexing switching switch 6, an induction signal switching switch 7, a microphone adaptive switching switch 8, a positive auxiliary channel switching switch 9, a negative auxiliary channel switching switch 10, and an analog ground switching switch 11.

[0035] The first audio and data multiplexing switch 5 is configured to switch between the left channel audio signal and the USB data negative signal.

[0036] The second audio and data multiplexing switch 6 is configured to switch between the right channel audio signal and the USB data positive signal.

[0037] The inductive signal switching switch 7 is configured to select different signal transmission paths to transmit ground-side signals based on the interface direction when the audio device is connected to the terminal device.

[0038] The microphone adaptive switch 8 is configured to select different signal transmission paths to transmit microphone signals based on the interface direction when the audio device is connected to the terminal device.

[0039] The positive auxiliary channel switch 9 is configured to select different signal transmission paths to transmit the positive auxiliary channel signal based on the interface direction when the audio device is connected to the terminal device.

[0040] The negative auxiliary channel switch 10 is configured to select different signal transmission paths to transmit the negative auxiliary channel signal based on the interface direction when the audio device is connected to the terminal device.

[0041] Analog ground switch 11 is configured to select whether to connect the motherboard ground path based on the operating state of the RF amplifier in the terminal device.

[0042] For details, please continue to refer to [the website / information]. Figure 3 The first audio and data multiplexing switch 5 is a DN_L switch, and the second audio and data multiplexing switch 6 is a DP_R switch. The microphone adaptive switch 8 is a MIC switch, which selects either SBU1 or SBU2 port to transmit the microphone signal based on the type of audio device access point. The induction signal switch 7 is a SENSE switch, which switches the audio ground signal to either GSBU1 or GSBU2 port based on the type of audio device access point, achieving ground polarity adaptive switching. The positive auxiliary channel switch 9 is an SBU2_H switch, and the negative auxiliary channel switch 10 is an SBU1_H switch.

[0043] Specifically, the first throw terminal SBU2 of the microphone adaptive switch 8 is connected sequentially to one of the throw terminals of the SBU1_H switch and one of the throw terminals of the SBU2_H switch, and is connected to the analog ground switch 11 through the SBU1_H switch and the SBU2_H switch. The second throw terminal SBU1 of the microphone adaptive switch 8 is connected sequentially to the other throw terminal of the SBU1_H switch and the other throw terminal of the SBU2_H switch, and is connected to the analog ground switch 11 through the SBU1_H switch and the SBU2_H switch.

[0044] In this embodiment, the first grounding point includes grounding point 16 and grounding point 17, both of which are grounding points of the small board 22. Grounding point 16 is located near the first switching switch 12, and grounding point 17 is located near the second switching switch 13. The first switching switch 12 is located near the SBU2 terminal, and the second switching switch 13 is located near the SBU1 terminal.

[0045] In another specific example, the analog ground switching switch includes: a ground switch 11 connected to a second ground point 15, which selects whether to connect the ground path of the motherboard 19 based on the operating state of the RF amplifier in the terminal device, so as to suppress the influence of RF interference on the audio signal.

[0046] In this embodiment, the common terminal of the first switch 12 is connected to the first input port of the connector 27, the first throw terminal of the first switch 12 is connected to the first ground point, and the second throw terminal of the first switch 12 is connected to the first throw terminal SBU2 of the microphone adaptive switch.

[0047] Furthermore, in this embodiment, the common terminal of the second switch 13 is connected to the other end of the connector 27, the first throw terminal is connected to the first ground point, and the second throw terminal is connected to the second throw terminal SBU1 of the microphone adaptive switch.

[0048] Furthermore, in this embodiment, when a non-Type-C data cable is plugged into the terminal device via a Type-C interface, the positive auxiliary channel switch 9 switches to the first throw terminal and is connected to the first switch 12; the negative auxiliary channel switch 10 switches to the second throw terminal and is connected to the second switch 13.

[0049] When the audio device is connected to the terminal device through the second end of the first data cable, and when a non-Type-C data cable is connected to the terminal device through the Type-C interface in reverse, the positive auxiliary channel switch 9 is switched to the second throw end and connected to the second switch 13; the negative auxiliary channel switch 10 is switched to the first throw end and connected to the first switch 12.

[0050] In this embodiment, the device that is not compatible with the first data line refers to a peripheral device that is identified by the baseband module of the terminal device as supporting only digital signal transmission and not supporting analog audio transmission, including but not limited to non-audio devices that are only used for USB data communication and DisplayPort video transmission.

[0051] Through the adaptive switching configuration of the multi-way switch, the corresponding signal transmission path can be automatically matched in different scenarios, such as when non-Type-C data cables are plugged into terminal devices in both the correct and reverse directions, and when non-audio peripherals that only support digital signal transmission are connected. While being compatible with different insertion directions and different types of peripherals, it ensures reliable transmission of analog audio signals and digital signals, avoids signal interference and path conflicts, and improves the universality of terminal device interfaces and the stability of audio use.

[0052] Example 2 Please refer to Figure 5 Based on the same inventive concept, this embodiment discloses an adaptive audio switching method, implemented using the adaptive audio switching circuit disclosed in Embodiment 1. The method includes: S1. When the terminal device is in the first working state and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch 12 or the second switch 13 is selected to transmit the grounding signal to the first grounding point set in the small board 22. S2. When the terminal device is in the second working state and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch 12 or the second switch 13 transmits the grounding signal to the second grounding point 15 located in the motherboard 19 through the third switch 4.

[0053] In this embodiment, when the terminal device is in different working states and the audio device is connected from different directions, the first switch 12 and the second switch 13 switch according to the following four cases: Scenario 1: When the RF amplifier in the terminal device is powered on and the audio device is connected to the terminal device via a Type-C data cable, the first switch 12 is connected to the first throw terminal SBU2 of the microphone adaptive switch 8, and the second switch 13 is connected to the second throw terminal SBU1 of the microphone adaptive switch 8; the analog ground switch 11 is switched to the first throw terminal SBU1, and the first switch 12 is grounded through the analog ground switch 11.

[0054] In addition, the first audio and data multiplexing switch 5 is connected to the L terminal (left channel output), and the second audio and data multiplexing switch 6 is connected to the R terminal (right channel output). The induction signal switch 7 is switched to the GSBU2 terminal, and the microphone adaptive switch 8 is switched to the SBU1 terminal.

[0055] In the above situation, the analog headset is grounded at 19 on the motherboard, which can effectively optimize the TDD noise problem; at the same time, when the RF power amplifier is working (that is, during 2G calls), the in-ear monitor and music playback functions will not be used, so there are no problems such as in-ear monitor feedback or poor music playback effect.

[0056] Scenario 2: When the RF amplifier in the terminal device is powered off, and the audio device is connected to the terminal device via a Type-C data cable, the first switch 12 is connected to the first ground point, and the second switch 13 is connected to the microphone adaptive switch.

[0057] At this time, the analog headphones are grounded on board 22. The headphone ground line is very short, the ground impedance is low, and the crosstalk between the left and right earpieces is small. This optimizes the problems of in-ear feedback and poor music playback in karaoke software.

[0058] At this time, the induction signal switching switch 7 switches to the GSBU2 terminal, the microphone adaptive switch 8 switches to the SBU1 terminal, and the grounding switch 11 switches to the SBU2_H switch 9 or is left floating.

[0059] Scenario 3: When the RF amplifier in the terminal device is powered on, and the audio device is connected to the terminal device via a reverse-plugged Type-C data cable, the first switch 12 is connected to the first throw terminal SUB2 of the microphone adaptive switch 8, and the second switch 13 is connected to the second throw terminal SUB1 of the microphone adaptive switch 8; the analog ground switch 11 is switched to the second throw terminal SUB2, and the second switch 13 is grounded through the analog ground switch 11.

[0060] In the above situation, the second switching switch 13 can be connected to the second grounding point 15 through the grounding switch, which can effectively optimize the TDD noise problem; at the same time, when the RF amplifier is working (i.e. during 2G calls), the earphone monitoring and music playback functions will not be used, so there are no problems such as earphone feedback or poor music playback effect.

[0061] At this time, the induction signal switching switch 7 switches to GSBU1, the microphone adaptive switch 8 switches to SBU2, and the grounding switch 11 switches to SBU1_H switch 10.

[0062] Scenario 4: When the RF amplifier in the terminal device is powered off, and the audio device is connected to the terminal device via a reverse-plugged Type-C data cable, the first switch 12 is connected to the microphone adaptive switch 8, and the second switch 13 is connected to the first grounding point.

[0063] The induction signal switching switch 7 is switched to GSBU1, the microphone adaptive switch 8 is switched to SBU2, and the grounding switch 11 is switched to SBU1_H switch 10 or left floating.

[0064] In the above situation, the analog headphones are grounded on the small board 22, the headphone ground line is very short, the ground impedance is small, and the crosstalk from the earpiece to the headphone mic and the crosstalk between the left and right earpieces of the headphones is small. This optimizes the problems of ear feedback and poor music playback effect in karaoke software.

[0065] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An adaptive audio switching circuit, characterized in that, include: Small board and motherboard; The small board is equipped with a first switching switch, a second switching switch, and a first grounding point. Both the first switching switch and the second switching switch are connected to the first grounding point. The motherboard is equipped with a third switch and a second grounding point. The first switch and the second switch are connected to the second grounding point through the third switch. When the terminal device is in the first working state and the audio device is connected to the terminal device through the first data line, the first switch or the second switch is selected to transmit the grounding signal to the first grounding point based on the access direction of the first data line. When the terminal device is in the second working state, and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch or the second switch is selected to transmit the grounding signal to the second grounding point through the third switch.

2. The adaptive audio switching circuit as claimed in claim 1, characterized in that, The small board contains a connector, which is electrically connected to the audio device.

3. The adaptive audio switching circuit as described in claim 2, characterized in that, The third switching switch includes a first audio and data multiplexing switching switch, a second audio and data multiplexing switching switch, a microphone adaptive switching switch, an induction signal switching switch, a positive auxiliary channel switching switch, a negative auxiliary channel switching switch, and an analog ground switching switch; The first audio and data multiplexing switch is configured to switch between the left channel audio signal and the USB data negative signal. The second audio and data multiplexing switch is configured to switch between the right channel audio signal and the USB data positive signal. The induction signal switching switch is configured to select different signal transmission paths to transmit induction signals based on the interface direction when the audio device is connected to the terminal device. The microphone adaptive switch is configured to select different signal transmission paths to transmit microphone signals based on the interface direction when the audio device is connected to the terminal device. The positive auxiliary channel switch is configured to select different signal transmission paths to transmit the positive auxiliary channel signal based on the interface direction when the audio device is connected to the terminal device. The negative auxiliary channel switch is configured to select different signal transmission paths to transmit the negative auxiliary channel signal based on the interface direction when the audio device is connected to the terminal device. The analog ground switch is configured to select whether to connect the motherboard ground path based on the operating state of the RF amplifier within the terminal device.

4. The adaptive audio switching circuit as described in claim 3, characterized in that, The common terminal of the first switch is connected to the first input port of the connector; the first throw terminal of the first switch is connected to the first ground point; the second throw terminal of the first switch is connected to the first throw terminal of the microphone adaptive switch, and the first throw terminal of the microphone adaptive switch is connected to the first throw terminal of the analog ground switch.

5. The adaptive audio switching circuit as described in claim 4, characterized in that, The common terminal of the second switch is connected to the second input port of the connector; the first throw terminal of the second switch is connected to the first ground point; the second throw terminal of the second switch is connected to the second throw terminal of the microphone adaptive switch, and the second throw terminal of the microphone adaptive switch is connected to the second throw terminal of the analog ground switch.

6. The adaptive audio switching circuit as described in claim 5, characterized in that, When the RF amplifier in the terminal device is powered off, and the audio device is connected to the terminal device via a Type-C data cable, the first switch is connected to the first ground point, and the second switch is connected to the second throw terminal of the microphone adaptive switch. When the RF amplifier in the terminal device is powered off, and the audio device is connected to the terminal device via a reverse-plugged Type-C data cable, the first switch is connected to the first throw terminal of the microphone adaptive switch, and the second switch is connected to the first grounding point.

7. The adaptive audio switching circuit as described in claim 5, characterized in that, When the RF amplifier in the terminal device is powered on and the audio device is connected to the terminal device via a Type-C data cable, the first switch is connected to the first throw terminal of the microphone adaptive switch, and the second switch is connected to the second throw terminal of the microphone adaptive switch; the analog ground switch is switched to the first throw terminal, and the first switch is grounded through the analog ground switch. When the RF amplifier in the terminal device is powered on, and the audio device is connected to the terminal device via a reverse-plugged Type-C data cable, the first switch is connected to the first throw terminal of the microphone adaptive switch, and the second switch is connected to the second throw terminal of the microphone adaptive switch; the analog ground switch is switched to the second throw terminal, and the second switch is grounded through the analog ground switch.

8. The adaptive audio switching circuit as described in claim 6, characterized in that, When a non-Type-C data cable is plugged into the terminal device via a Type-C interface, the positive auxiliary channel switch is switched to the first throw terminal and connected to the first switch; the negative auxiliary channel switch is switched to the second throw terminal and connected to the second switch.

9. The adaptive audio switching circuit as described in claim 8, characterized in that, When a non-Type-C data cable is plugged into the terminal device via the Type-C interface in reverse, the positive auxiliary channel switch is switched to the second throw terminal and connected to the second switch; the negative auxiliary channel switch is switched to the first throw terminal and connected to the first switch.

10. An adaptive audio switching method, characterized in that, The method includes: When the terminal device is in the first working state and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch or the second switch is selected to transmit the grounding signal to the first grounding point set in the small board. When the terminal device is in the second working state and the audio device is connected to the terminal device through the first data line, based on the access direction of the first data line, the first switch or the second switch transmits the grounding signal to the second grounding point set in the motherboard through the third switch.

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