Earphone switching circuit and earphone thereof

Abstract

The embodiment of the utility model discloses an earphone switching circuit and an earphone thereof, and the earphone switching circuit comprises a switching module which comprises a first detection end, a second detection end and a signal output end; the signal input end of the audio decoder is connected with the signal output end of the switching module; the earphone interface comprises a microphone port and a grounding port, the microphone port is connected with the first detection end, and the grounding port is connected with the second detection end; when the switching module is in an initial power-on state, the first detection end and the signal output end are conducted; and the switching module is used for conducting the connection between the second detection end and the signal output end and disconnecting the connection between the first detection end and the signal output end according to the voltage of the first detection end and the voltage of the second detection end. According to the embodiment of the utility model, the connection mode of the signal output end is switched through the switching module according to the voltage of the detection end, earphones of different standards can be compatible, and the universality of the earphones is improved.

Description

Technical Field

[0001] This utility model relates to the field of electronic technology, and in particular to a headphone switching circuit and a headphone thereof. Background Technology

[0002] Currently, headphones on the market are mainly divided into in-ear, over-ear, in-ear, and over-ear types. The plugs are mainly divided into three-segment and four-segment types. The 3.5mm three-segment headphones commonly used in large devices such as computers only have three pins: GND, left, and right channels. This interface is simple but has an obvious drawback: it lacks a microphone (MIC) port, making recording and phone calls impossible. Therefore, a four-segment headphone jack with an added microphone port is undoubtedly a cost-effective solution. However, due to different manufacturer definitions, four-segment jacks are divided into the national standard OMTP and the international standard CTIA. Therefore, four-segment headphones are not completely universal and still have some shortcomings, mainly in terms of compatibility and switching between CTIA and OMTP for the headphone microphone port. Utility Model Content

[0003] The main technical problem solved by this utility model embodiment is to provide a headphone switching circuit and a corresponding headphone, which can solve the problem of poor compatibility of existing headphones.

[0004] To solve the above-mentioned technical problems, the present invention provides a headphone switching circuit, comprising: a switching module including a first detection terminal, a second detection terminal, and a signal output terminal; an audio decoder, the signal input terminal of which is connected to the signal output terminal of the switching module; and a headphone jack including a microphone port and a ground port, the microphone port of which is connected to the first detection terminal, and the ground port of which is connected to the second detection terminal; in the initial power-on state, the first detection terminal and the signal output terminal are connected; the switching module is used to connect the second detection terminal and the signal output terminal and disconnect the first detection terminal and the signal output terminal according to the voltage of the first detection terminal and the voltage of the second detection terminal.

[0005] In some embodiments, when the switching module detects that the voltage of the first detection terminal is less than a first preset threshold and the voltage of the second detection terminal is greater than a second preset threshold, it connects the second detection terminal and the signal output terminal and disconnects the first detection terminal and the signal output terminal; when the switching module detects that the voltage of the first detection terminal is greater than the second preset threshold and the voltage of the second detection terminal is less than the first preset threshold, it connects the first detection terminal and the signal output terminal and disconnects the second detection terminal and the signal output terminal.

[0006] In some embodiments, the switching module is further configured to: maintain the current connection when it is detected that the voltage of the first detection port and the voltage of the second detection port are both less than the first preset threshold.

[0007] In some embodiments, the headphone switching circuit further includes a steady-state module, the input of which is connected to the detection output of the audio decoder, and the output of which is connected to the signal output of the switching module. The audio decoder is configured to output a protection signal to the steady-state module after power-on initialization, and the steady-state module is configured to output a steady-state voltage to the signal output of the switching module in response to the protection signal, so as to suppress the noise generated by the switching module when switching connection modes.

[0008] In some embodiments, the switching module includes a switching chip U1, a resistor R1, a capacitor C1, a capacitor C2, and a ferrite bead FB1. The first detection terminal of the switching chip U1 is connected to the microphone port of the headphone jack, the second detection terminal of the switching chip U1 is connected to the ground port of the headphone jack, the power input terminal of the switching chip U1 is connected to the first terminal of the capacitor C1 and the first terminal of the resistor R1, the second terminal of the resistor R1 is connected to a first power supply, the replacement detection terminal of the switching chip is connected to the first terminal of the capacitor C2, the signal output terminal of the switching chip is connected to the first terminal of the ferrite bead FB1, the second terminal of the ferrite bead FB1 is connected to the signal input terminal of the audio decoder, and the second terminals of the capacitors C1 and C2 are connected to a first reference ground.

[0009] In some embodiments, the steady-state module includes a steady-state unit and a filtering unit. The input terminal of the steady-state unit is connected to the detection output terminal of the audio decoder. The output terminal of the steady-state unit is connected to the input terminal of the filtering unit and the signal output terminal of the switching module. The output terminal of the filtering unit is connected to the signal input terminal of the audio decoder. The steady-state unit is used to output a steady-state voltage to the signal output terminal of the switching module in response to the protection signal. The filtering unit is used to filter the microphone signal output by the signal output terminal of the switching module.

[0010] In some embodiments, the steady-state unit includes resistors R3, R4, R5, R6, and R7, capacitor C3, switching transistor M1, and switching transistor M2. The first terminal of resistor R3 is connected to the detection output terminal of the audio decoder and the first terminal of resistor R4. The second terminal of resistor R4 is connected to the first terminal of capacitor C3 and the gate of switching transistor M1. The drain of switching transistor M1 is connected to the first terminals of resistors R5 and R6 and the gate of switching transistor M2. The second terminal of resistor R5 is connected to a second power supply. The drain of switching transistor M2 is connected to the first terminal of resistor R7. The source of switching transistor M2 is connected to a first power supply. The second terminal of resistor R7 is connected to the signal output terminal of the switching module. The second terminals of resistors R3, C3, M1, and R6 are connected to a second reference ground.

[0011] In some embodiments, the filtering unit includes resistors R8 and R9, capacitors C4 and C5. The first end of resistor R8 is connected to the signal output terminal of the switching module and the first end of resistor R9. The second end of resistor R8 is connected to the first end of capacitor C4 and the first end of capacitor C5. The second end of capacitor C4 is connected to the first signal input terminal of the audio decoder. The second end of capacitor C5 is connected to the second signal input terminal of the audio decoder. The second end of resistor R9 is connected to a first reference ground.

[0012] In some embodiments, the first preset threshold is 60mV and the second preset threshold is 1V.

[0013] To solve the above-mentioned technical problems, another technical solution adopted by this utility model is to provide an earphone, including the earphone switching circuit described above.

[0014] The beneficial effects of this utility model embodiment are as follows: Unlike the prior art, this utility model embodiment switches the connection mode of the signal output terminal according to the voltage of the detection terminal through the switching module, and sets a steady-state module to provide a steady-state voltage, which can be compatible with headphones of different standards, while effectively suppressing noise during the switching process, and improving the versatility and sound quality of the headphones. Attached Figure Description

[0015] Figure 1 This is a structural diagram of an earphone switching circuit provided in an embodiment of the present invention;

[0016] Figure 2 This is a structural diagram of another headphone switching circuit provided in an embodiment of the present invention;

[0017] Figure 3This is a circuit schematic diagram of a switching module and a filtering unit provided in an embodiment of the present invention;

[0018] Figure 4 This is a circuit diagram of a steady-state unit provided in an embodiment of the present invention. Detailed Implementation

[0019] To facilitate understanding of this utility model, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0021] Figure 1 A schematic diagram of a headphone switching circuit according to an embodiment of this application is shown. The headphone switching circuit includes an audio decoder 100, a switching module 200, and a headphone jack 300. The signal input terminal of the audio decoder 100 is connected to the signal output terminal of the switching module 200, and is used to receive and process microphone signals from the switching module 200.

[0022] The switching module 200 includes a first detection terminal, a second detection terminal, and a signal output terminal. The first detection terminal is used to connect to the microphone port of the headphone jack 300, and the second detection terminal is used to connect to the ground port of the headphone jack 300. When the headphone switching circuit is initially powered on, the first detection terminal and the signal output terminal of the switching module 200 are in a conducting state. At this time, the headphone switching circuit is connected to a headphone of the national standard (OMTP) by default.

[0023] The headphone jack 300 includes a microphone port and a ground port. The microphone port is connected to the first detection terminal of the switching module 200 via a wire, while the ground port is connected to the second detection terminal of the switching module 200. By employing a dual-port detection method, the specific type of the inserted headphones can be accurately determined.

[0024] The switching module 200 uses two voltage thresholds to determine the earphone standard. When the voltage at the first detection terminal is less than the first preset threshold (60mV) and the voltage at the second detection terminal is greater than the second preset threshold (1V), the switching module 200 automatically connects the second detection terminal to the signal output terminal and simultaneously disconnects the first detection terminal from the signal output terminal. This operation enables the switching from the Chinese national standard (OMTP) to the American standard (CTIA).

[0025] Conversely, when the voltage at the first detection terminal is greater than the second preset threshold (1V) and the voltage at the second detection terminal is less than the first preset threshold (60mV), the switching module 200 will maintain the conduction state between the first detection terminal and the signal output terminal, while simultaneously disconnecting the connection between the second detection terminal and the signal output terminal. This operation ensures the normal use of the national standard (OMTP) headset.

[0026] For compatibility handling of three-segment headphones, when the switching module 200 detects that the voltages at both the first and second detection terminals are less than a first preset threshold (60mV), the headphone switching circuit will maintain the current connection state. This design allows the circuit to automatically identify and adapt to three-segment headphones without requiring manual adjustment by the user.

[0027] The voltage detection mechanism of the switching module 200 is based on the voltage distribution characteristics after the headphones are plugged in. For CTIA standard headphones, the positions of the microphone and ground terminals are opposite to those of the OMTP standard headphones. Therefore, the specific standard of the headphones can be accurately determined by detecting the voltage values ​​of the two ports. The setting of the first preset threshold (60mV) and the second preset threshold (1V) takes into account voltage fluctuations and interference factors in practical applications, ensuring the accuracy and stability of the detection.

[0028] In practical applications, when a user plugs in headphones, the switching module 200 immediately performs voltage detection and system standard determination. The entire switching process is completed automatically, and the user does not need to worry about the specific system standard of the headphones being used. This design greatly improves the versatility of headphones and solves the compatibility problem of headphones with different system standards. Figure 1 As shown in the circuit structure, the audio decoder 100 can accurately receive the audio signal processed by the switching module 200. Regardless of the type of headphones used by the user, the system can automatically adjust the connection method to ensure correct transmission of the sound signal.

[0029] Figure 2 A schematic diagram of another headphone switching circuit provided in an embodiment of this application is shown. This headphone switching circuit... Figure 1 The illustrated embodiment adds a steady-state module 400 to suppress noise generated during system switching. The headphone switching circuit includes an audio decoder 100, a switching module 200, a headphone jack 300, and a steady-state module 400.

[0030] The audio decoder 100 has a signal input terminal and a detection output terminal. The signal input terminal is connected to the signal output terminal of the switching module 200 and is used to receive and process the audio signal from the switching module 200. The detection output terminal is connected to the input terminal of the steady-state module 400 and is used to output a protection signal to the steady-state module 400.

[0031] The switching module 200 includes a first detection terminal, a second detection terminal, and a signal output terminal. The first detection terminal is connected to the microphone port of the headphone jack 300, and the second detection terminal is connected to the ground port of the headphone jack 300. The signal output terminal is connected to the signal input terminal of the audio decoder 100 and also to the output terminal of the steady-state module 400. When the system is initially powered on, the first detection terminal and the signal output terminal of the switching module 200 are in a conductive state, and the system defaults to connecting to a standard (OMTP) headphone.

[0032] The headphone jack 300 includes a microphone port and a ground port. The microphone port is connected to the first detection terminal of the switching module 200 via a wire, and the ground port is connected to the second detection terminal of the switching module 200 via a wire. This dual-port design allows the system to accurately determine the type of the plugged-in headphones through voltage detection.

[0033] The input terminal of the steady-state module 400 is connected to the detection output terminal of the audio decoder 100, and its output terminal is connected to the signal output terminal of the switching module 200. After power-on initialization, the audio decoder 100 outputs a protection signal to the steady-state module 400 through its detection output terminal. Upon receiving this protection signal, the steady-state module 400 provides a steady-state voltage to the signal output terminal of the switching module 200 to suppress noise during the system switching process.

[0034] During operation, when a user inserts headphones, the switching module 200 detects the voltage values ​​of the first and second detection terminals. If the voltage at the first detection terminal is less than a first preset threshold (60mV) and the voltage at the second detection terminal is greater than a second preset threshold (1V), it indicates that a CTIA standard headphone has been inserted. At this time, the switching module 200 automatically connects the second detection terminal to the signal output terminal and simultaneously disconnects the first detection terminal from the signal output terminal. During the switching process, the steady-state module 400 continuously provides a steady-state voltage to ensure that the switching action does not generate significant noise interference.

[0035] When the voltage at the first detection terminal is greater than the second preset threshold (1V) and the voltage at the second detection terminal is less than the first preset threshold (60mV), it indicates that an OMT (OMTP) standard headset has been inserted. The switching module 200 maintains the conduction state between the first detection terminal and the signal output terminal, while ensuring that the second detection terminal and the signal output terminal are disconnected. The steady-state module 400 operates continuously throughout the process to ensure signal stability.

[0036] For three-segment headphones, when the switching module 200 detects that the voltages at both the first and second detection terminals are less than a first preset threshold (60mV), the system will maintain the current connection state. Even during the use of the three-segment headphones, the steady-state module 400 still plays its role in stabilizing the voltage, ensuring the transmission quality of the audio signal.

[0037] Figure 2 The headphone switching circuit shown effectively solves the noise problem during system switching by adding a steady-state module 400. While maintaining the function of automatically recognizing and switching between different headphone systems, it provides a more stable and higher-quality audio experience. This circuit structure has good compatibility and reliability in practical applications, fully meeting users' needs for headphone use.

[0038] The introduction of the steady-state module 400 not only improves the performance of the circuit but also enhances the overall system's anti-interference capability. Working in conjunction with the audio decoder 100, the steady-state module 400 can respond promptly to changes in system state, providing the necessary voltage support for the switching process.

[0039] Figure 3 The detailed circuit structure of the switching module 200 and the filtering unit 420 in this embodiment of the present invention is shown. The switching module 200 uses a switching chip U1 as the core device, and works with peripheral circuits to realize the automatic identification and switching function of the earphone mode.

[0040] The switching chip U1 has multiple functional ports, including a power input terminal VCC, a replacement detection terminal PHR, a signal output terminal MIC, a first detection terminal GM1, a second detection terminal GM2, and a ground terminal G. Among them, the VCC terminal is used for power supply, and the replacement detection terminal PHR and the signal output terminal MIC are used for audio signal input and output, respectively.

[0041] In the peripheral circuit of the switching module 200, the first end of resistor R1 is connected to the power input terminal VCC of the switching chip U1, and the second end is connected to the first power supply (+3V3), which is used to provide a stable operating voltage for the switching chip U1. The first end of capacitor C1 is connected to the power input terminal VCC of the switching chip U1, and the second end is grounded (AGND), which is used to filter out power supply ripple and ensure the stability of the chip's operating voltage.

[0042] The first terminal of capacitor C2 is connected to the replacement detection terminal PHR of switching chip U1, and the second terminal is grounded (AGND) to provide a stable detection reference voltage. The first terminal of ferrite bead FB1 is connected to the signal output terminal MIC of switching chip U1, and the second terminal is connected to the signal input terminal of audio decoder 100 to suppress high-frequency interference and ensure the transmission quality of audio signals.

[0043] The filter unit 420 includes resistors R8 and R9, and capacitors C4 and C5. The first terminals of resistors R8 and R9 are both connected to the signal output terminal MIC of the switching module 200. The second terminal of resistor R8 is connected to the first terminals of both capacitors C4 and C5. The second terminal of capacitor C4 is connected to the first signal input terminal (FHP_MIC_L) of the audio decoder 100, and the second terminal of capacitor C5 is connected to the second signal input terminal (FHP_MIC_R) of the audio decoder 100. The second terminal of resistor R9 is grounded (AGND). This RC filter circuit can effectively filter out high-frequency noise in the microphone signal.

[0044] In actual operation, when headphones are plugged into headphone jack 300, switching chip U1 detects the headphone's standard type via the first detection terminal GM1 and the second detection terminal GM2. For CTIA standard headphones, because the microphone end corresponding to the first detection terminal GM1 is grounded, the voltage at GM1 is pulled down to ground level (less than 60mV), while the voltage at the second detection terminal GM2 remains high (greater than 1V). At this time, switching chip U1 automatically connects the second detection terminal GM2 to the signal output terminal MIC, achieving correct connection for CTIA standard headphones.

[0045] For OMTP standard headphones, after insertion, the voltage at the first detection terminal GM1 will remain within the MIC impedance voltage division range (greater than 1V), while the voltage at the second detection terminal GM2 will be lower (less than 60mV). In this case, the switching chip U1 keeps the first detection terminal GM1 and the MIC terminal in a conducting state to ensure that the headphones work normally.

[0046] When a three-segment headphone is plugged in, due to the lack of a microphone, the voltages of both the first detection terminal GM1 and the second detection terminal GM2 will be pulled low to ground level (both less than 60mV). After the switching chip U1 recognizes this state, it will maintain the current connection method, thus achieving compatibility with the three-segment headphone.

[0047] The filtering unit 420 plays a continuous role throughout the entire operation. The RC filter network composed of resistors R8 and R9 and capacitors C4 and C5 filters the audio signal input from the microphone, removing any possible high-frequency interference components. The filtered audio signal is then input to the audio decoder 100 through two paths, FHP_MIC_L and FHP_MIC_R, ensuring the purity of the audio signal.

[0048] The FB1 ferrite bead plays a crucial role in audio signal transmission. As a special inductive component, the FB1 effectively suppresses high-frequency noise while having virtually no impact on audio signal transmission. This design further enhances the system's anti-interference capability and audio quality.

[0049] Figure 3 The circuit structure shown fully embodies the technical features of this invention. Through reasonable component selection and circuit design, automatic identification and switching of different headphone standards are achieved, while ensuring the transmission quality of audio signals.

[0050] Figure 4 The detailed circuit structure of the steady-state unit 410 in this embodiment of the present invention is shown. The steady-state unit 410 mainly consists of resistors R3 to R7, capacitor C3, and switching transistors M1 and M2, forming a voltage regulation control circuit. This circuit provides a stable reference voltage for the switching module by processing the DEPOP signal, effectively suppressing noise during the switching process.

[0051] The first terminal of resistor R3 is connected to the detection output terminal DEPOP of the audio decoder 100, and the second terminal is grounded (GND). The first terminal of resistor R4 is also connected to the DEPOP terminal, and the second terminal is connected to the first terminal of capacitor C3 and the gate of switching transistor M1. The second terminal of capacitor C3 is grounded and connected to the source of switching transistor M1. This circuit stage constitutes the primary processing unit for the DEPOP signal.

[0052] The drain of switching transistor M1 is connected through three branches: the first branch is resistor R5, the other end of which is connected to the second power supply (+12V); the second branch is resistor R6, the other end of which is grounded; and the third branch is the gate of switching transistor M2. Switching transistor M1 and the associated resistors constitute a voltage control stage used to regulate the stability of the output voltage.

[0053] The source of switching transistor M2 is connected to the first power supply (+3V3), and its drain is connected to the MIC_VREF terminal through resistor R7. Switching transistor M2 and resistor R7 constitute the final regulated output stage, providing a stable reference voltage MIC_VREF for the switching module.

[0054] During system operation, after initialization, the audio decoder 100 outputs a high-level protection signal through the DEPOP terminal. This signal is first divided by R3 and R4, and then filtered by capacitor C3 to obtain a relatively smooth control voltage applied to the gate of the switching transistor M1.

[0055] When the DEPOP signal is high, switch M1 is turned on. After M1 is turned on, its drain voltage decreases, and through the voltage division effect of R5 and R6, a suitable bias voltage is formed at the gate of M2. The bias voltage causes M2 to enter the conducting state. At this time, the source and drain of M2 form a stable conducting path, providing a stable reference voltage MIC_VREF to the switching module through R7.

[0056] The connection of resistor R5 to the +12V power supply ensures sufficient operating voltage when M1 is turned on. The grounding of resistor R6 provides a stable bias reference for the gate of M2. The placement of resistor R7 at the output terminal limits the output current, further improving voltage stability.

[0057] When the system switches earphone standards, the change in connection status may cause voltage fluctuations, resulting in noise. The stable reference voltage MIC_VREF output by the steady-state unit 410 effectively suppresses the effects of these voltage fluctuations. This voltage is connected to the signal output of the switching module, providing stable voltage support for the entire switching process.

[0058] The addition of capacitor C3 is crucial for system stability. On one hand, it filters out high-frequency components in the DEPOP signal, making control smoother; on the other hand, it suppresses the influence of external interference on the control circuit. Through RC filtering, the purity of the control signal is ensured.

[0059] In practical applications, Figure 4 The circuit structure shown exhibits excellent performance. Precise regulation of the reference voltage is achieved through the cascaded control of switching transistors M1 and M2. Appropriate component selection and circuit parameter settings enable the circuit to respond quickly to changes in system state and provide a stable voltage output.

[0060] The design of the entire steady-state unit 410 fully considers practical application requirements. The setting of all grounding points and the selection of power supply voltage have been carefully calculated to ensure reliable circuit operation.

[0061] In other embodiments of this application, an earphone is also provided, which includes an earphone switching circuit as provided in any of the above embodiments.

[0062] It should be noted that while the preferred embodiments of this utility model are provided in the specification and accompanying drawings, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of this utility model; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of this utility model specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A headphone switching circuit, characterized in that, include: The switching module includes a first detection terminal, a second detection terminal, and a signal output terminal; An audio decoder, wherein the signal input terminal of the audio decoder is connected to the signal output terminal of the switching module; as well as The headphone jack includes a microphone port and a ground port. The microphone port of the headphone jack is connected to the first detection terminal, and the ground port of the headphone jack is connected to the second detection terminal. In the initial power-on state, the first detection terminal and the signal output terminal of the switching module are connected; the switching module is used to connect the second detection terminal and the signal output terminal and disconnect the first detection terminal and the signal output terminal according to the voltage of the first detection terminal and the voltage of the second detection terminal.

2. The headphone switching circuit according to claim 1, characterized in that, When the switching module detects that the voltage of the first detection terminal is less than a first preset threshold and the voltage of the second detection terminal is greater than a second preset threshold, it connects the second detection terminal and the signal output terminal and disconnects the first detection terminal and the signal output terminal. When the switching module detects that the voltage at the first detection terminal is greater than the second preset threshold and the voltage at the second detection terminal is less than the first preset threshold, it connects the first detection terminal and the signal output terminal and disconnects the second detection terminal and the signal output terminal.

3. The headphone switching circuit according to claim 2, characterized in that, The switching module is also used for: When the voltage at both the first detection terminal and the second detection terminal is detected to be less than the first preset threshold, the current connection is maintained.

4. The headphone switching circuit according to claim 1, characterized in that, It also includes a steady-state module, the input of which is connected to the detection output of the audio decoder, and the output of which is connected to the signal output of the switching module; The audio decoder is used to output a protection signal to the steady-state module after power-on initialization. The steady-state module is used to respond to the protection signal and output a steady-state voltage to the signal output terminal of the switching module to suppress the noise generated by the switching module when switching connection modes.

5. The headphone switching circuit according to claim 1, characterized in that, The switching module includes a switching chip U1, a resistor R1, a capacitor C1, a capacitor C2, and a ferrite bead FB1. The first detection terminal of the switching chip U1 is connected to the microphone port of the headphone jack, the second detection terminal of the switching chip U1 is connected to the ground port of the headphone jack, the power input terminal of the switching chip U1 is connected to the first terminal of the capacitor C1 and the first terminal of the resistor R1, the second terminal of the resistor R1 is connected to the first power supply, the replacement detection terminal of the switching chip is connected to the first terminal of the capacitor C2, the signal output terminal of the switching chip is connected to the first terminal of the ferrite bead FB1, the second terminal of the ferrite bead FB1 is connected to the signal input terminal of the audio decoder, and the second terminals of the capacitor C1 and the second terminals of the capacitor C2 are connected to the first reference ground.

6. The headphone switching circuit according to claim 4, characterized in that, The steady-state module includes a steady-state unit and a filtering unit. The input terminal of the steady-state unit is connected to the detection output terminal of the audio decoder. The output terminal of the steady-state unit is connected to the input terminal of the filtering unit and the signal output terminal of the switching module. The output terminal of the filtering unit is connected to the signal input terminal of the audio decoder. The steady-state unit is used to respond to the protection signal and output a steady-state voltage to the signal output terminal of the switching module; The filtering unit is used to filter the microphone signal output from the signal output terminal of the switching module.

7. The headphone switching circuit according to claim 6, characterized in that, The steady-state unit includes resistors R3, R4, R5, R6, and R7, capacitor C3, switching transistor M1, and switching transistor M2. The first end of resistor R3 is connected to the detection output terminal of the audio decoder and the first end of resistor R4. The second end of resistor R4 is connected to the first end of capacitor C3 and the gate of switching transistor M1. The drain of switching transistor M1 is connected to the first end of resistor R5, the first end of resistor R6 and the gate of switching transistor M2. The second end of resistor R5 is connected to the second power supply. The drain of switching transistor M2 is connected to the first end of resistor R7. The source of switching transistor M2 is connected to the first power supply. The second end of resistor R7 is connected to the signal output terminal of the switching module. The second end of resistor R3, the second end of capacitor C3, the source of switching transistor M1 and the second end of resistor R6 are connected to the second reference ground.

8. The headphone switching circuit according to claim 6, characterized in that, The filtering unit includes resistor R8, resistor R9, capacitor C4, and capacitor C5. The first end of resistor R8 is connected to the signal output terminal of the switching module and the first end of resistor R9. The second end of resistor R8 is connected to the first end of capacitor C4 and the first end of capacitor C5. The second end of capacitor C4 is connected to the first signal input terminal of the audio decoder. The second end of capacitor C5 is connected to the second signal input terminal of the audio decoder. The second end of resistor R9 is connected to the first reference ground.

9. The headphone switching circuit according to claim 2, characterized in that, The first preset threshold is 60mV, and the second preset threshold is 1V.

10. An earphone, characterized in that, include: The headphone switching circuit as described in any one of claims 1-9.

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