Magnetic type earphone interface circuit and portable terminal

Abstract

The utility model discloses an earphone interface circuit based on magnetic attraction and a portable terminal, the portable terminal comprises a housing and a magnetic attraction earphone, the housing is internally provided with a mainboard and a magnetic attraction earphone interface, the mainboard is provided with a codec and an earphone interface circuit, the contact point of the magnetic attraction earphone interface is arranged on the surface of the housing, and the magnetic attraction earphone interface circuit is arranged on the surface of the housing. The earphone interface circuit is connected with the magnetic earphone interface; the magnetic attraction earphone is magnetically attracted to the magnetic attraction earphone interface, and the earphone interface circuit detects the connection state of the magnetic attraction earphone according to the change of the magnetic flux on the contact point and controls transmission and processing of earphone signals between the codec and the magnetic attraction earphone interface according to the connection state. An existing earphone interface is replaced by the magnetic attraction earphone interface, the contact point of the magnetic attraction earphone interface is directly exposed on the surface of the shell, the magnetic attraction earphone is magnetically attracted to the magnetic attraction earphone interface, and corresponding earphone signals are transmitted through the contact point. Holes do not need to be formed in the shell, no foreign matter enters the magnetic attraction earphone interface, and the problem that an existing hole type interface is not waterproof is solved.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, and in particular to a magnetic-based earphone interface circuit and a portable terminal. Background Art

[0002] The headphone interface of existing portable terminals (such as mobile phones and tablets) usually adopts a 3.5mm interface (coaxial audio jack with a diameter of 3.5mm) or a type-c interface. This requires opening a hole in the shell of the portable terminal to expose the interface, foreign matter may enter the interface, and water may accidentally enter the interface, which may affect the sound quality. Severe water ingress may even burn the internal motherboard and cause it to malfunction. The waterproof effect is very poor and the development cycle is also long.

[0003] Therefore the prior art still needs to be improved and enhanced. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a magnetic headphone interface circuit and a portable terminal to solve the problem that the existing open-hole interface is not waterproof.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A magnetic headphone interface circuit is provided, which connects the magnetic headphone interface and the codec, and comprises a magnetic detection module and an audio transmission module; the magnetic detection module is connected to the codec, and the audio transmission module is connected to the magnetic headphone interface;

[0007] The magnetic detection module detects the connection status of the magnetic earphone according to the magnetic flux on the magnetic earphone interface, and outputs a detection signal of a corresponding level to the codec;

[0008] The audio transmission module performs protection filtering processing on the transmitted headphone signal.

[0009] In the magnetic headphone interface circuit, the magnetic detection module includes a Hall switch, a first resistor and a second resistor;

[0010] The OUTPUT pin of the Hall switch is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the second resistor and the interface detection pin of the codec, the other end of the second resistor is connected to the power supply end, the GND pin of the Hall switch is grounded, and the VDD pin of the Hall switch is connected to the power supply end.

[0011] In the magnetic headphone interface circuit, the magnetic detection module further includes a first protection diode, a first capacitor and a second capacitor;

[0012] One end of the first protection diode is connected to the OUTPUT pin of the Hall switch, one end of the first capacitor and one end of the first resistor; the other end of the first protection diode is connected to the other end of the first capacitor and ground, and the second capacitor is connected between the VDD pin of the Hall switch and ground.

[0013] In the magnetic headphone interface circuit, the audio transmission module includes a first magnetic bead, a second magnetic bead, a third magnetic bead, a fourth magnetic bead, a fifth magnetic bead, a first inductor, a third capacitor, a fourth capacitor, a third resistor, a fourth resistor and a fifth resistor;

[0014] One end of the first magnetic bead is connected to the microphone pin of the magnetic headphone interface, the other end of the first magnetic bead is connected to the microphone pin of the codec, one end of the second magnetic bead is connected to the ground pin of the magnetic headphone interface, one end of the fifth magnetic bead and one end of the third capacitor; the other end of the fifth magnetic bead is connected to one end of the third resistor, one end of the fourth resistor and one end of the fourth capacitor; the other end of the third resistor is connected to the audio power ground pin of the codec, the other end of the fourth resistor is connected to one end of the fifth resistor and the ground, the other end of the fifth resistor inputs the broadcast ground signal, the other end of the fourth capacitor is connected to the headphone pin of the codec, the other end of the third capacitor is connected to one end of the first inductor and inputs the broadcast signal, the other end of the first inductor is grounded, the other end of the second magnetic bead is connected to the microphone pin of the codec, one end of the third magnetic bead is connected to the left channel pin of the magnetic headphone interface, the other end of the third magnetic bead is connected to the left channel pin of the codec, one end of the fourth magnetic bead is connected to the right channel pin of the magnetic headphone interface, and the other end of the fourth magnetic bead is connected to the right channel pin of the codec.

[0015] In the magnetic headphone interface circuit, the audio transmission module further includes a sixth resistor, a seventh resistor, a fifth capacitor and a sixth capacitor;

[0016] One end of the sixth resistor is connected to one end of the fifth capacitor and the other end of the third magnetic bead, the other end of the sixth resistor is connected to the left channel pin of the codec, one end of the seventh resistor is connected to one end of the sixth capacitor and the other end of the fourth magnetic bead, the other end of the seventh resistor is connected to the right channel pin of the codec, and the other end of the fifth capacitor and the other end of the sixth capacitor are both grounded.

[0017] In the magnetic headphone interface circuit, the audio transmission module further includes a second protection diode, a third protection diode and a fourth protection diode;

[0018] The second protection diode is connected between one end of the first magnetic bead and the ground, the third protection diode is connected between the other end of the third magnetic bead and the ground, and the fourth protection diode is connected between the other end of the fourth magnetic bead and the ground.

[0019] In the magnetic headphone interface circuit, the audio transmission module also includes an eighth resistor and a ninth resistor, one end of the eighth resistor is connected to the other end of the sixth resistor and the left channel pin of the codec, the other end of the eighth resistor is grounded, one end of the ninth resistor is connected to the other end of the seventh resistor and the right channel pin of the codec, and the other end of the ninth resistor is grounded.

[0020] A portable terminal comprises a housing and a magnetic earphone, wherein a mainboard is arranged in the housing, a codec is arranged on the mainboard, wherein a magnetic earphone interface is also arranged in the housing, a contact point of the magnetic earphone interface is arranged on the housing surface, and a magnetic earphone interface circuit is also arranged on the mainboard, and the earphone interface circuit is connected to the magnetic earphone interface;

[0021] The magnetic earphone is magnetically attracted to the magnetic earphone interface, and the earphone interface circuit detects the connection state of the magnetic earphone according to the change of magnetic flux on the contact point, and controls the transmission and processing of the earphone signal between the codec and the magnetic earphone interface according to the connection state.

[0022] In the portable terminal, the magnetic earphone interface is arranged on the edge of the shell.

[0023] Compared with the prior art, the utility model provides a magnetic headphone interface circuit and a portable terminal, the portable terminal includes a shell and a magnetic headphone, a mainboard is provided in the shell, a codec and a magnetic headphone interface circuit are provided on the mainboard, a magnetic headphone interface is also provided in the shell, the contact point of the magnetic headphone interface is provided on the shell surface, the headphone interface circuit is connected to the magnetic headphone interface; the magnetic headphone is magnetically attracted to the magnetic headphone interface, the headphone interface circuit detects the connection state of the magnetic headphone according to the change of the magnetic flux on the contact point, and controls the transmission and processing of the headphone signal between the codec and the magnetic headphone interface according to the connection state. A magnetic headphone interface is used to replace the existing headphone interface, the contact point of the magnetic headphone interface is directly exposed on the shell surface, the magnetic headphone is directly attracted to the magnetic headphone interface, and the corresponding headphone signal is transmitted through the contact point. There is no need to open a hole in the shell, and no foreign matter will enter the magnetic headphone interface, and the problem that the existing hole-type interface cannot be waterproof is also solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a structural block diagram of the portable terminal provided by the utility model.

[0025] Figure 2 This is a schematic diagram of the location of the magnetic headphone jack provided by the utility model on a portable terminal.

[0026] Figure 3 The present invention provides a circuit diagram of the headphone interface circuit. DETAILED DESCRIPTION

[0027] The utility model provides a magnetic headphone interface circuit and a portable terminal. In order to make the purpose, technical solution and effect of the utility model clearer and more specific, the utility model is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model. The system optimizes the circuit design and structural design, optimizes the smoke detection method, greatly improves the smoke sensitivity, and thus improves the detection accuracy of the composite fire detector.

[0028] Please also see Figure 1 and Figure 2 The portable terminal provided in this embodiment includes a shell and a magnetic earphone, wherein a main board and a magnetic earphone interface 10 are arranged in the shell, and four contact points 11 of the magnetic earphone interface (respectively a microphone contact point, a ground contact point, a left sound contact point and a right sound contact point) are arranged on the surface of the shell, and a magnetic earphone interface circuit 20 based on magnetic attraction is arranged on the main board, and the magnetic earphone is magnetically attracted to the magnetic earphone interface, and the earphone interface circuit 20 is connected to the magnetic earphone interface 10, and the earphone interface circuit 20 detects the connection state of the magnetic earphone according to the change of the magnetic flux on the contact point, and controls the transmission and processing of the earphone signal between the codec 30 and the magnetic earphone interface according to the connection state.

[0029] This embodiment uses a magnetic headphone jack to replace the existing headphone jack. The contact point of the magnetic headphone jack is directly exposed on the surface of the shell. The matching magnetic headphone is directly attached to the magnetic headphone jack, and the corresponding headphone signal is transmitted through the contact point. There is no need to open a hole in the shell, and foreign matter will not enter the magnetic headphone jack. It also solves the problem that the existing hole-type interface cannot be waterproof.

[0030] The magnetic headphone jack 10 can be arranged on the edge of the housing. Figure 2 Any dotted box shown or the location of the existing 3.5mm headphone jack can preferably be set outside the antenna or in an area far away from the antenna without interfering with the antenna. It does not need to be set on the motherboard, which facilitates the selection of the headphone jack location and saves space on the motherboard. The headphone jack circuit on the motherboard is set on the side adjacent to the magnetic headphone jack to facilitate the electrical connection between the headphone jack circuit and the magnetic headphone socket.

[0031] It should be understood that the magnetic headphone jack 10 is a prior art, which includes a seat, a contact point 11, a magnet, etc., such as a magnetic headphone jack model M-BP973. Here, the existing headphone jack circuit is mainly improved so that it can identify the magnetic state and signal transmission.

[0032] Please also read Figure 3The main board is provided with an existing codec (Codec, preferably MT6368) 30, and the headphone interface circuit 20 includes a magnetic detection module 21 and an audio transmission module 22; the magnetic detection module 21 is connected to the codec 30, and the audio transmission module 22 is connected to the magnetic headphone interface 10. The magnetic detection module 21 detects the connection status of the magnetic headphone according to the change of the magnetic flux on the magnetic headphone interface and outputs a detection signal EAR_DETECT of a corresponding level to the codec 30, and the audio transmission module 22 performs protection filtering processing on the transmitted headphone signal (including the microphone signal HP_MIC, the left channel signal AU_HPL, the right channel signal AU_HPR, and FM_ANT_P / N).

[0033] The magnetic detection module 21 includes a Hall switch U1, a first resistor R1 and a second resistor R2; the OUTPUT pin of the Hall switch U1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to one end of the second resistor R2 and the interface detection pin of the codec 30, the other end of the second resistor R2 is connected to the power supply end (providing the power supply voltage VIO18_PMU), the GND pin of the Hall switch U1 is grounded, and the VDD pin of the Hall switch U1 is connected to the power supply end.

[0034] The Hall switch U1 is preferably of the model AS1800D4RN, which can detect the change of the magnetic field on the magnetic headphone jack 10 and output a detection signal EAR_DETECT of a corresponding level, which is transmitted to the codec 30 to determine whether a headphone is connected.

[0035] Specifically: when there is no magnetic earphone, the magnetic flux change is 0, the OUTPUT pin of the Hall switch U1 is pulled up to a high level by R1 and R2, and the detection signal EAR_DETECT is a high level at this time. The codec 30 determines that no magnetic earphone is connected, and no earphone signal is transmitted.

[0036] When the magnetic earphone is close to the magnetic port of the magnetic earphone interface 10, the magnet inside the magnetic earphone interface 10 will attract the magnetic earphone, and the entire magnetic port will be in full contact with the magnetic earphone, and the signal pins of the magnetic earphone will be in contact and electrically connected with the contact points 11 of the magnetic earphone interface. At this time, the Hall switch U1 detects the change in magnetic flux and pulls the OUTPUT pin low. At this time, the detection signal EAR_DETECT is correspondingly pulled down to a low level, and the codec 30 determines that a magnetic earphone is connected, completing the entire earphone detection process, and the subsequent earphone signal is transmitted normally.

[0037] Preferably, the magnetic detection module 21 also includes a first protection diode D1, a first capacitor C1 and a second capacitor C2; one end of the first protection diode D1 is connected to the OUTPUT pin of the Hall switch U1, one end of the first capacitor C1 and one end of the first resistor R1; the other end of the first protection diode D1 is connected to the other end of the first capacitor C1 and the ground, and the second capacitor C2 is connected between the VDD pin of the Hall switch U1 and the ground.

[0038] The first protection diode D1 is preferably an electrostatic protection diode of model AU0521PZ, which is combined with the first capacitor to provide electrostatic protection and signal filtering for the OUTPUT pin of the Hall switch U1. The second capacitor C2 is used to filter the power supply voltage VIO18_PMU on the VDD pin of the Hall switch U1.

[0039] The audio transmission module 22 includes a first magnetic bead FB1, a second magnetic bead FB2, a third magnetic bead FB3, a fourth magnetic bead FB4, a fifth magnetic bead FB5, a first inductor L1, a third capacitor C3, a fourth capacitor C4, a third resistor R3, a fourth resistor R4 and a fifth resistor R5; one end of the first magnetic bead FB1 is connected to the microphone pin TP7507 of the magnetic headphone interface 10 (TP7507 is electrically connected to the microphone contact point), and the other end of the first magnetic bead FB1 is connected to the microphone pin of the codec 30 (transmitting the microphone signal HP _MIC), one end of the second magnetic bead FB2 is connected to the ground pin TP7508 of the magnetic headphone jack 10 (TP7508 is electrically connected to the ground contact point), one end of the fifth magnetic bead FB5 and one end of the third capacitor C3; the other end of the fifth magnetic bead FB5 is connected to one end of the third resistor R3, one end of the fourth resistor R4 and one end of the fourth capacitor C4; the other end of the third resistor R3 is connected to the audio power ground pin of the codec 30 (providing a return GND signal AVSS28_AUD), the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5 and the ground, the other end of the fifth resistor R5 inputs the broadcast ground signal FM_ANT_N, the other end of the fourth capacitor C4 is connected to the headphone pin of the codec 30 (transmitting the earphone differential ground signal EAR_JACK_GND), the other end of the third capacitor C3 is connected to one end of the first inductor L1 and inputs the broadcast signal FM_ANT_P, the other end of the first inductor L1 is grounded, the other end of the second magnetic bead FB2 is connected to the microphone pin of the codec 30 (transmitting the headphone reference ground signal AU_REFN), the third One end of the magnetic bead FB3 is connected to the left channel pin TP7509 of the magnetic headphone interface 10 (TP7509 is electrically connected to the left acoustic contact point), the other end of the third magnetic bead FB3 is connected to the left channel pin of the codec 30 (transmitting the left channel signal AU_HPL), one end of the fourth magnetic bead FB4 is connected to the right channel pin TP7511 of the magnetic headphone interface 10 (TP7511 is electrically connected to the right acoustic contact point), and the other end of the fourth magnetic bead FB4 is connected to the right channel pin of the codec 30 (transmitting the right channel signal AU_HPR).

[0040] Among them, the first magnetic bead FB1, the second magnetic bead FB2, the third magnetic bead FB3 and the fourth magnetic bead FB4 are respectively used to filter out the headphone interference caused by the radio frequency TDD (time division duplex, a communication method for time-sharing processing of sending and receiving signals) on the signal lines connected thereto.

[0041] After the magnetic earphone is inserted, it can also be used as an antenna to realize the broadcast (FM) function. The magnetic earphone interface 10 receives the broadcast ground signal FM_ANT_N and the broadcast signal FM_ANT_P, which are processed by the audio transmission module 22 and transmitted to the existing four-in-one (including WIFI, Bluetooth, GPS and FM) short-distance communication chip (preferably MT6625L) on the mainboard for processing. C3 is used for direct isolation (audio signals cannot pass, only broadcast signals pass), L1 is used to filter out interference and clutter on the signal, and FB5 is used to isolate the two broadcast signals and conduct the audio ground return. R3, R4, and R5 act as ground jumpers; R4 selects whether to connect according to the grounding requirements, and when connected, they are connected to the same ground (GND); when not connected, the return GND signal AVSS28_AUD is connected to the headset differential ground signal EAR_JACK_GND through R3, and the broadcast ground signal FM_ANT_N is grounded (GND). During specific implementation, C3, FB5, L1, R3, R4, and R5 may also choose not to be installed and the broadcast function may be deleted.

[0042] Preferably, the audio transmission module 22 also includes a sixth resistor R6, a seventh resistor R7, a fifth capacitor C5 and a sixth capacitor C6; one end of the sixth resistor R6 is connected to one end of the fifth capacitor C5 and the other end of the third magnetic bead FB3, the other end of the sixth resistor R6 is connected to the left channel pin of the codec 30, one end of the seventh resistor R7 is connected to one end of the sixth capacitor C6 and the other end of the fourth magnetic bead FB4, the other end of the seventh resistor R7 is connected to the right channel pin of the codec 30, and the other end of the fifth capacitor C5 and the other end of the sixth capacitor C6 are both grounded.

[0043] Among them, the resistance value of the sixth resistor R6 and the seventh resistor R7 is preferably 10Ω; the capacity of the fifth capacitor C5 and the sixth capacitor C6 is preferably 100nF and the withstand voltage is 16V; R6 and C5 are grouped together, and R7 and C6 are grouped together to form LC low-pass filters respectively, which are used to filter interference above 15.9KHz on the left and right channels.

[0044] Preferably, the audio transmission module 22 also includes a second protection diode D2, a third protection diode D3 and a fourth protection diode D4; the second protection diode D2 is connected between one end of the first magnetic bead FB1 and the ground, the third protection diode D3 is connected between the other end of the third magnetic bead FB3 and the ground, and the fourth protection diode D4 is connected between the other end of the fourth magnetic bead FB4 and the ground.

[0045] The second protection diode D2 , the third protection diode D3 and the fourth protection diode D4 are preferably electrostatic protection diodes of model AU0521PZ, which are used for electrostatic protection to avoid damage to the codec 30 .

[0046] Preferably, the audio transmission module 22 also includes an eighth resistor R8 and a ninth resistor R9, one end of the eighth resistor R8 is connected to the other end of the sixth resistor R6 and the left channel pin of the codec 30, the other end of the eighth resistor R8 is grounded, one end of the ninth resistor R9 is connected to the other end of the seventh resistor R7 and the right channel pin of the codec 30, and the other end of the ninth resistor R9 is grounded.

[0047] Among them, the eighth resistor R8 and the ninth resistor R9 are pull-down resistors, and the resistance value is preferably 470Ω. When non-magnetic headphones are connected, the signals on the left and right channel pins are pulled down to avoid noise.

[0048] Preferably, the audio transmission module 22 also includes a seventh capacitor C7 and an eighth capacitor C8, one end of the seventh capacitor C7 is connected to the other end of the third magnetic bead FB3 and one end of the sixth resistor R6, the other end of the seventh capacitor C7 is grounded, one end of the eighth capacitor C8 is connected to the other end of the fourth magnetic bead FB4 and one end of the seventh resistor R7, and the other end of the eighth capacitor C8 is grounded.

[0049] Among them, the capacitance of the seventh capacitor C7 and the eighth capacitor C8 is preferably 33pF, with a withstand voltage of 25V, and is used to filter the signals on the left and right channel pins.

[0050] In summary, the utility model provides a magnetic headphone interface circuit and portable terminal, which changes the existing 3.5mm headphone jack into a magnetic headphone interface. The contact point of the magnetic headphone interface is directly exposed on the shell surface, and the magnetic headphone is magnetically attracted to the magnetic headphone interface. The corresponding headphone signal is transmitted through the contact point. In this way, there is no need to open a hole in the shell, and no foreign matter will enter the shell, which solves the problem that the existing hole-type interface cannot be waterproof. The magnetic headphone interface can be set in any area of ​​the shell edge except the antenna, such as the front or side of the battery cover, to reduce the impact on the antenna and not occupy the motherboard space.

[0051] The division of the above functional modules is only for illustration. In practical applications, the above functions can be assigned to different functional modules as needed, that is, divided into different functional modules to complete all or part of the functions described above.

[0052] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and utility model concept of the utility model, and all these changes or substitutions should fall within the protection scope of the claims attached to the utility model.

Claims

1. A magnetic headphone interface circuit, connecting a magnetic headphone interface and a codec, characterized in that: It includes a magnetic detection module and an audio transmission module; the magnetic detection module is connected to the codec, and the audio transmission module is connected to the magnetic headphone interface; The magnetic detection module detects the connection status of the magnetic earphone according to the magnetic flux on the magnetic earphone interface, and outputs a detection signal of a corresponding level to the codec; The audio transmission module performs protection filtering processing on the transmitted headphone signal.

2. The magnetic headphone interface circuit according to claim 1, characterized in that: The magnetic detection module includes a Hall switch, a first resistor and a second resistor; The OUTPUT pin of the Hall switch is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the second resistor and the interface detection pin of the codec, the other end of the second resistor is connected to the power supply end, the GND pin of the Hall switch is grounded, and the VDD pin of the Hall switch is connected to the power supply end.

3. The magnetic headphone interface circuit according to claim 2, characterized in that: The magnetic detection module also includes a first protection diode, a first capacitor and a second capacitor; One end of the first protection diode is connected to the OUTPUT pin of the Hall switch, one end of the first capacitor and one end of the first resistor; the other end of the first protection diode is connected to the other end of the first capacitor and ground, and the second capacitor is connected between the VDD pin of the Hall switch and ground.

4. The magnetic headphone interface circuit according to claim 2, characterized in that: The audio transmission module includes a first magnetic bead, a second magnetic bead, a third magnetic bead, a fourth magnetic bead, a fifth magnetic bead, a first inductor, a third capacitor, a fourth capacitor, a third resistor, a fourth resistor and a fifth resistor; One end of the first magnetic bead is connected to the microphone pin of the magnetic headphone interface, the other end of the first magnetic bead is connected to the microphone pin of the codec, one end of the second magnetic bead is connected to the ground pin of the magnetic headphone interface, one end of the fifth magnetic bead and one end of the third capacitor; the other end of the fifth magnetic bead is connected to one end of the third resistor, one end of the fourth resistor and one end of the fourth capacitor; the other end of the third resistor is connected to the audio power ground pin of the codec, the other end of the fourth resistor is connected to one end of the fifth resistor and the ground, the other end of the fifth resistor inputs the broadcast ground signal, the other end of the fourth capacitor is connected to the headphone pin of the codec, the other end of the third capacitor is connected to one end of the first inductor and inputs the broadcast signal, the other end of the first inductor is grounded, the other end of the second magnetic bead is connected to the microphone pin of the codec, one end of the third magnetic bead is connected to the left channel pin of the magnetic headphone interface, the other end of the third magnetic bead is connected to the left channel pin of the codec, one end of the fourth magnetic bead is connected to the right channel pin of the magnetic headphone interface, and the other end of the fourth magnetic bead is connected to the right channel pin of the codec.

5. The magnetic headphone interface circuit according to claim 4, characterized in that: The audio transmission module also includes a sixth resistor, a seventh resistor, a fifth capacitor and a sixth capacitor; One end of the sixth resistor is connected to one end of the fifth capacitor and the other end of the third magnetic bead, the other end of the sixth resistor is connected to the left channel pin of the codec, one end of the seventh resistor is connected to one end of the sixth capacitor and the other end of the fourth magnetic bead, the other end of the seventh resistor is connected to the right channel pin of the codec, and the other end of the fifth capacitor and the other end of the sixth capacitor are both grounded.

6. The magnetic headphone interface circuit according to claim 4, characterized in that: The audio transmission module also includes a second protection diode, a third protection diode and a fourth protection diode; The second protection diode is connected between one end of the first magnetic bead and the ground, the third protection diode is connected between the other end of the third magnetic bead and the ground, and the fourth protection diode is connected between the other end of the fourth magnetic bead and the ground.

7. The magnetic headphone interface circuit according to claim 5, characterized in that: The audio transmission module also includes an eighth resistor and a ninth resistor, one end of the eighth resistor is connected to the other end of the sixth resistor and the left channel pin of the codec, the other end of the eighth resistor is grounded, one end of the ninth resistor is connected to the other end of the seventh resistor and the right channel pin of the codec, and the other end of the ninth resistor is grounded.

8. A portable terminal, comprising a housing and a magnetic earphone, wherein a mainboard is arranged in the housing, and a codec is arranged on the mainboard, wherein: A magnetic headphone jack is further provided in the shell, and a contact point of the magnetic headphone jack is arranged on the surface of the shell. The mainboard is further provided with a magnetic headphone jack circuit according to any one of claims 1 to 7, and the headphone jack circuit is connected to the magnetic headphone jack. The magnetic earphone is magnetically attracted to the magnetic earphone interface, and the earphone interface circuit detects the connection state of the magnetic earphone according to the change of magnetic flux on the contact point, and controls the transmission and processing of the earphone signal between the codec and the magnetic earphone interface according to the connection state.

9. The portable terminal according to claim 8, characterized in that: The magnetic headphone interface is arranged on the edge of the shell.

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