Earphone compatible circuit and portable terminal device

Abstract

The invention provides an earphone compatible circuit and a portable terminal device. The earphone compatible circuit comprises an audio codec, a processor, a channel switcher and an earphone interface. When it is detected that an earphone is inserted into the earphone interface, the audio codec can judge whether the earphone is a PTT earphone or not to obtain a judgment result and transmit the judgment result to the processor, so that the processor can obtain the judgment result. Therefore, the processor can generate the control signal according to the judgment result and transmit the control signal to the channel switcher, so that the channel switcher can obtain the control signal. Therefore, the channel switcher can switch between the first channel and the second channel in the channel switcher according to the control signal so as to be compatible with the PTT earphone.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a headphone compatibility circuit and a portable terminal device. Background Art

[0002] A portable terminal device (personal data assistance, PDA) is a smart terminal device that is specifically applied to scenarios such as industry, logistics, and retail, and integrates data collection, processing, and communication functions. In a PDA, a push-to-talk (PTT) communication function similar to the walkie-talkie mode is often used. However, a PDA usually only supports conventional headphones such as CTIA headphones or OMTP headphones, and cannot be compatible with PTT headphones. Summary of the Invention

[0003] This application provides a headphone compatibility circuit and a portable terminal device that can be compatible with PTT headphones.

[0004] In a first aspect, this application provides a headphone compatibility circuit, which includes: an audio codec, a processor, a channel switch, and a headphone interface;

[0005] The audio codec is electrically connected to the first end of the processor and the first end of the channel switch respectively. The second end of the processor is electrically connected to the second end of the channel switch. The third end of the channel switch is electrically connected to the headphone interface. The third end of the processor is electrically connected between the third end of the channel switch and the headphone interface;

[0006] The audio codec is configured to, when detecting that a headphone is inserted into the headphone interface, determine whether the headphone is a PTT headphone, obtain a determination result, and transmit the determination result to the processor;

[0007] The processor is configured to generate a control signal according to the determination result and transmit the control signal to the channel switch;

[0008] The channel switch is configured to switch between a first channel and a second channel in the channel switch according to the control signal to be compatible with the PTT headphone.

[0009] Through the headphone compatibility circuit provided by the first aspect, when it is detected that a headphone is inserted into the headphone jack, the audio codec can determine whether the headphone is a PTT headphone, obtain a determination result, and transmit the determination result to the processor, so that the processor can obtain the determination result. In this way, the processor can generate a control signal according to the determination result and transmit the control signal to the channel switch, so that the channel switch can obtain the control signal. Thus, the channel switch can switch between the first channel and the second channel in the channel switch according to the control signal to be compatible with the PTT headphone.

[0010] In a possible design, the audio codec is specifically configured to, when it is detected that the headphone is inserted into the headphone jack, detect the magnitude relationship between the impedance of the right headphone in the headphone and a preset impedance to obtain the determination result; if the impedance of the right headphone in the headphone is greater than the preset impedance, the determination result indicates that the headphone is the PTT headphone; if the impedance of the right headphone in the headphone is less than the preset impedance, the determination result indicates that the headphone is a CTIA headphone or an OMTP headphone.

[0011] In a possible design, the processor is specifically configured to control the level of the control signal to be a first level when the determination result indicates that the headphone is the PTT headphone; or control the level of the control signal to be a second level when the determination result indicates that the headphone is a CTIA headphone or an OMTP headphone.

[0012] In a possible design, the channel switch is specifically configured to switch from the first channel to the second channel when the level of the control signal is the first level, or switch to the first channel when the level of the control signal is the second level.

[0013] In a possible design, the headphone compatibility circuit further includes: a voltage dividing circuit;

[0014] The control end of the voltage dividing circuit is used to access a driving signal, the first end of the voltage dividing circuit is used to access a first voltage, and the second end of the voltage dividing circuit is electrically connected between the third end of the channel switch and the headphone jack;

[0015] The voltage dividing circuit is configured to conduct according to the driving signal when the PTT headphone is inserted into the headphone jack to change the potential of the headphone jack;

[0016] The processor is further configured to detect the potential of the headphone jack to determine whether the button of the PTT headphone is in a released state. If the potential of the headphone jack is detected to be the second level, it is determined that the button of the PTT headphone is in a released state; if the potential of the headphone jack is detected to be the first level, it is determined that the button is not in a released state.

[0017] In a possible design, the voltage dividing circuit includes: a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor, and a DIP switch;

[0018] The first ends of the first voltage dividing resistor, the second voltage dividing resistor, and the third voltage dividing resistor are all used to connect to the first voltage. The second ends of the first voltage dividing resistor, the second voltage dividing resistor, and the third voltage dividing resistor are all electrically connected to the first end of the DIP switch. The second end of the DIP switch is electrically connected between the third end of the channel switcher and the headphone jack.

[0019] In a possible design, the right headphone in the PTT headphone includes: the button, a first resistor, and a second resistor;

[0020] The first resistor and the second resistor are connected in parallel. The second resistor is connected in series with the button. The series-connected second resistor and button are electrically connected to the right interface in the headphone jack.

[0021] In a possible design, when the resistance value of the first resistor is 4.7 KΩ and the resistance value of the second resistor is 2.1 KΩ, the resistance value of the first voltage dividing resistor is 9.6 KΩ;

[0022] Alternatively, when the resistance value of the first resistor is 6.8 KΩ and the resistance value of the second resistor is 2.1 KΩ, the resistance value of the second voltage dividing resistor is 12.5 KΩ;

[0023] Alternatively, when the resistance value of the first resistor is 9.1 KΩ and the resistance value of the second resistor is 2.1 KΩ, the resistance value of the third voltage dividing resistor is 15.6 KΩ.

[0024] In a possible design, the channel switcher includes: a third resistor and a single-pole double-throw switch;

[0025] The first end of the third resistor is electrically connected to the second end of the processor. The second end of the third resistor is electrically connected to the enable end of the single-pole double-throw switch. The common end of the single-pole double-throw switch is electrically connected to the audio codec. The normally open end of the single-pole double-throw switch is electrically connected to the headphone jack.

[0026] In a second aspect, the present application provides a portable terminal device, which includes: the headphone compatibility circuit in the first aspect and each possible design of the first aspect.

[0027] For the portable terminal device provided in the above second aspect and each possible design of the second aspect, the beneficial effects can be referred to the beneficial effects brought by the first aspect and each possible implementation manner of the first aspect, which will not be elaborated here.

[0028] The above description is only an overview of the technical solutions of the embodiments of the present application. In order to understand the technical means of the embodiments of the present application more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features and advantages of the embodiments of the present application more obvious and understandable, the following specific embodiments of the present application are given. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0030] Figure 1 It is a schematic structural diagram of a headphone compatibility circuit provided by an embodiment of the present application;

[0031] Figure 2 For Figure 1 It is a schematic structural diagram of a kind of headphone supported by the headphone compatibility circuit in Detailed Description of the Embodiments

[0032] In the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (item)" or its similar expression below refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a alone, b alone or c alone can represent: a alone, b alone, c alone, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0033] The orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0034] The terms "connected" and "coupled" should be understood in a broad sense. For example, the "connection" or "coupling" of a circuit structure can refer not only to a physical connection, but also to an electrical connection or a signal connection. For example, it can be a direct connection, that is, a physical connection, or it can be indirectly connected through at least one intermediate element, as long as the circuit is connected. It can also be the communication inside two elements; the signal connection can be through a circuit for signal connection, or it can also refer to signal connection through a media medium, such as radio waves. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0035] First, the professional terms involved in the embodiments of the present application are explained.

[0036] The push-to-talk (PTT) communication function means that when the button is pressed, voice can be sent; when the button is released, voice can be received. The PTT communication function is suitable for scenarios that require quick and short communication, such as in warehouse sorting, logistics scheduling, and patrol inspection, etc.

[0037] A CTIA headset refers to a headset that conforms to the international standard (Consumer Technology Industry Association, CTIA), and its pin connection method is left channel - right channel - ground wire - microphone.

[0038] An OMTP headset refers to a headset that conforms to the standard specified by the Open Mobile Terminal Platform (OMTP), and this standard is also known as the national standard. Its pin connection method is left channel - right channel - microphone - ground wire.

[0039] A PTT headset refers to a headset with a PTT communication function, which is mainly used in scenarios that require instant communication. The PTT headset has a dedicated button. When this button is pressed, the microphone of the PTT headset is activated, and the user can make a voice call through the PTT headset; when the button is released, the voice call stops.

[0040] Refer to Figure 1 , Figure 1 For a schematic structural diagram of a headset compatibility circuit provided by an embodiment of the present application. As Figure 1As shown, the headphone compatibility circuit 100 may include: an audio codec 110, a processor 120, a channel switch 130, and a headphone interface 140.

[0041] The audio codec 110 is electrically connected to the first end of the processor 120 and the first end of the channel switch 130 respectively. The second end of the processor 120 is electrically connected to the second end of the channel switch 130. The third end of the channel switch 130 is electrically connected to the headphone interface 140. The third end of the processor 120 is electrically connected between the third end of the channel switch 130 and the headphone interface 140.

[0042] Among them, the audio codec 110, the processor 120, the channel switch 130, and the headphone interface 140 may be separately provided or integrated. The embodiments of the present application do not make specific limitations on this.

[0043] Among them, the headphone interface 140 may include: a microphone interface M, a ground interface G, a right interface R, and a left interface L.

[0044] When detecting that a headphone is inserted into the headphone interface 140, the audio codec 110 may determine whether the headphone is a PTT headphone to obtain a determination result. And the audio codec 110 may transmit the determination result to the processor 120 so that the processor 120 can obtain the determination result.

[0045] In some examples, when detecting that a headphone is inserted into the headphone interface 140, the audio codec 110 may detect the magnitude relationship between the impedance of the right headphone in the headphone and a preset impedance to determine whether the headphone is a PTT headphone to obtain a determination result. If the impedance of the right headphone in the headphone is greater than the preset impedance, the audio codec 110 may determine that the headphone is a PTT headphone. If the impedance of the right headphone in the headphone is less than the preset impedance, the audio codec 110 may determine that the headphone is a CTIA headphone or an OMTP headphone.

[0046] Among them, the preset impedance is, for example, 1000 Ω.

[0047] Among them, Figure 2 is Figure 1 a schematic structural diagram of a type of headphone supported in the headphone compatibility circuit. As Figure 2 shown, when a CTIA headphone is connected to the headphone interface 140, the left headphone SPK_L2 in the CTIA headphone is electrically connected to the left interface L, the right headphone SPK_R2 in the CTIA headphone is electrically connected to the right interface R, the left headphone SPK_L2, the right headphone SPK_R2, the microphone MIC2, and the button HOOK in the CTIA headphone are all electrically connected to the ground interface G, and the microphone MIC2 and the button HOOK in the CTIA headphone are both electrically connected to the microphone interface M.

[0048] Thus, the processor 120 can generate a control signal PTT_EN according to the judgment result. Moreover, the processor 120 can transmit the control signal PTT_EN to the channel switch 130, enabling the channel switch 130 to obtain the control signal PTT_EN.

[0049] In some examples, when the judgment result indicates that the earphone is a PTT earphone, the processor 120 can control the level of the control signal PTT_EN to be a first level. Alternatively, when the judgment result indicates that the earphone is a CTIA earphone or an OMTP earphone, the processor 120 can control the level of the control signal PTT_EN to be a second level.

[0050] Among them, the specifications of CTIA earphones, OMTP earphones, and PTT earphones are all 3.5 mm.

[0051] Exemplarily, the first level is a low level, and the second level is a high level. Among them, when no earphone is plugged into the earphone interface 140, the processor 120 can control the level of the control signal PTT_EN to be the second level. That is to say, the second level is the initial level of the control signal PTT_EN.

[0052] Thereby, the channel switch 130 can switch between the first channel and the second channel in the channel switch 130 according to the control signal PTT_EN, enabling the earphone compatibility circuit 100 to be compatible with PTT earphones.

[0053] In some examples, when the level of the control signal PTT_EN is the first level, the channel switch 130 can switch from the first channel to the second channel, enabling the earphone compatibility circuit 100 to support PTT earphones.

[0054] Alternatively, when the level of the control signal PTT_EN is the second level, the channel switch 130 can switch to the first channel, enabling the audio signal HPH_R to be transmitted from the audio codec 110 to the earphone interface 140. That is to say, when a CTIA earphone or an OMTP earphone is plugged into the earphone interface 140, the audio signal HPH_R can be transmitted from the audio codec 110 to the earphone interface 140.

[0055] Figure 1 In this case, the first end of the processor 120 is denoted as 1, the second end of the processor 120 is denoted as 2, the third end of the processor 120 is denoted as 3, the first end of the channel switch 130 is denoted as 1, the second end of the channel switch 130 is denoted as 2, and the third end of the channel switch 130 is 3.

[0056] The headphone compatibility circuit provided by this application can, when detecting that a headphone is inserted into the headphone jack, enable the audio codec to determine whether the headphone is a PTT headphone, obtain a determination result, and transmit the determination result to the processor, so that the processor can obtain the determination result. Thus, the processor can generate a control signal according to the determination result and transmit the control signal to the channel switch, so that the channel switch can obtain the control signal. Consequently, the channel switch can switch between the first channel and the second channel in the channel switch according to the control signal to be compatible with the PTT headphone.

[0057] Based on the description of the above embodiments, exemplarily, a possible implementation manner of the headphone compatibility circuit 100. As Figure 1 shown, the headphone compatibility circuit 100 may further include: a voltage dividing circuit 150.

[0058] The control end of the voltage dividing circuit 150 is used to access a driving signal, the first end of the voltage dividing circuit 150 is used to access a first voltage, and the second end of the voltage dividing circuit 150 is electrically connected between the third end of the channel switch 130 and the headphone jack 140.

[0059] Wherein, the first voltage is, for example, 4V.

[0060] When a PTT headphone is inserted into the headphone jack 140, the voltage dividing circuit 150 can be turned on according to the driving signal to change the potential of the headphone jack 140.

[0061] In this way, the processor 120 can detect the potential of the headphone jack 140 to determine whether the PTTF button of the PTT headphone is in the released state. If it is detected that the potential of the headphone jack 140 is the second level, the processor 120 can determine that the PTTF button of the PTT headphone is in the released state. That is to say, when PTT_INT is at a high level, the processor 120 can determine that the PTTF button of the PTT headphone is in the released state. At this time, it means that the headphone compatibility circuit 100 can receive voice.

[0062] If it is detected that the potential of the headphone jack 140 is the first level, the processor 120 can determine that the PTTF button is not in the released state. That is to say, when PTT_INT is at a low level, the processor 120 can determine that the PTTF button is in the pressed state. At this time, it means that the headphone compatibility circuit 100 can send voice.

[0063] Based on the description of the above embodiments, exemplarily, a possible implementation manner of the voltage dividing circuit 150. As Figure 1 shown, the voltage dividing circuit 150 may include: a first voltage dividing resistor Rb1, a second voltage dividing resistor Rb2, a third voltage dividing resistor Rb3, and a DIP switch S2.

[0064] The first ends of the first voltage-dividing resistor Rb1, the second voltage-dividing resistor Rb2, and the third voltage-dividing resistor Rb3 are all used to connect to a first voltage. The second ends of the first voltage-dividing resistor Rb1, the second voltage-dividing resistor Rb2, and the third voltage-dividing resistor Rb3 are all electrically connected to the first end of the DIP switch S2. The second end of the DIP switch S2 is electrically connected between the third end of the channel switch 130 and the headphone jack 140.

[0065] Based on the description of the above embodiments, exemplarily, a possible implementation of the voltage-dividing circuit 150. As Figure 1 shown, the right headphone in the PTT headphone may include: a PTTF button, a first resistor R1, and a second resistor R2.

[0066] The first resistor R1 and the second resistor R2 are connected in parallel. The second resistor R2 is connected in series with the PTTF button. The series-connected second resistor R2 and the PTTF button are electrically connected to the right interface R in the headphone jack 140.

[0067] Among them, when the PTT headphone is connected to the headphone jack 140, the left headphone SPK_L1 in the PTT headphone is electrically connected to the left interface L, the microphone MIC2 in the PTT headphone is electrically connected to the microphone interface M, and the left headphone SPK_L1, the right headphone, and the microphone MIC1 in the PTT headphone are also all electrically connected to the ground interface G.

[0068] Among them, when different types of PTT headphones are connected to the headphone jack 140, the corresponding bit numbers of the DIP switch S2 in the voltage-dividing circuit 150 are turned on according to the drive signal, so that the voltage-dividing resistor corresponding to the bit number can change the potential of the headphone jack 140 through voltage division.

[0069] Among them, different types may include: a first type, a second type, and a third type.

[0070] Among them, as Figure 1 shown, the voltage-dividing resistors corresponding to the bit numbers from left to right in the DIP switch S2 are the first voltage-dividing resistor Rb1, the second voltage-dividing resistor Rb2, and the third voltage-dividing resistor Rb3 in sequence.

[0071] In some examples, when the resistance value of the first resistor R1 is 4.7 KΩ and the resistance value of the second resistor R2 is 2.1 KΩ, that is, when the PTT headphone is a first-type PTT headphone, the resistance value of the first voltage-dividing resistor Rb1 is 9.6 KΩ.

[0072] Or, when the resistance value of the first resistor R1 is 6.8 KΩ and the resistance value of the second resistor R2 is 2.1 KΩ, that is, when the PTT headphone is a second-type PTT headphone, the resistance value of the second voltage-dividing resistor Rb2 is 12.5 KΩ.

[0073] Alternatively, when the resistance value of the first resistor R1 is 9.1 KΩ and the resistance value of the second resistor R2 is 2.1 KΩ, that is, when the PTT earphone is a third-type PTT earphone, the resistance value of the third voltage-dividing resistor Rb3 is 15.6 KΩ.

[0074] Among them, according to the general purpose input / output (GPIO) interface with a working voltage of 1.8V, the low level corresponding to complementary metal-oxide-semiconductor (CMOS) is less than 0.63V, and the high level corresponding to CMOS is greater than 1.17V. Therefore, for different resistance values of the first resistor R1, that is, for different types of PTT earphones, by setting the corresponding voltage-dividing resistor Rb, when the button PTTF is in the pressed state, PTT_INT is at a low level, that is, the first level, and when the button PTTF is in the released state, PTT_INT is at a high level, that is, the second level.

[0075] Table 1 shows the levels of PTT_INT corresponding to different types of PTT earphones

[0076]

[0077] Based on the description of the above embodiments, exemplarily, a possible implementation manner of the channel switch 130. As Figure 1 shown, the channel switch 130 may include: a third resistor R3 and a single-pole double-throw switch S1.

[0078] The first end of the third resistor R3 is electrically connected to the second end of the processor 120, the second end of the third resistor R3 is electrically connected to the enable end IN of the single-pole double-throw switch S1, the common end COM of the single-pole double-throw switch S1 is electrically connected to the audio codec 110, and the normally open end NO of the single-pole double-throw switch S1 is electrically connected to the headphone interface 140.

[0079] Among them, when the control signal PTT_EN is at the first level, the common end COM of the single-pole double-throw switch S1 is electrically connected to the normally closed end NC of the single-pole double-throw switch S1, so that the channel switch 130 switches from the first channel to the second channel. When the control signal PTT_EN is at the second level, the common end COM of the single-pole double-throw switch S1 is electrically connected to the normally open end NO of the single-pole double-throw switch S1, so that the channel switch 130 switches to the first channel.

[0080] The embodiment of the present application further provides a portable terminal device, which may include: a headphone compatibility circuit 100.

[0081] The portable terminal device provided by the embodiment of the present application has the same beneficial effects as the headphone compatibility circuit provided by the embodiment of the present application, which will not be elaborated here.

[0082] Finally, it should be noted that the above embodiments are only specific implementation manners of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A headphone compatibility circuit, characterized in that, The headphone compatibility circuit includes: an audio codec, a processor, a channel switch, and a headphone interface; The audio codec is electrically connected to the first end of the processor and the first end of the channel switch respectively. The second end of the processor is electrically connected to the second end of the channel switch. The third end of the channel switch is electrically connected to the headphone interface. The third end of the processor is electrically connected between the third end of the channel switch and the headphone interface; The audio codec is configured to, when detecting that a headphone is inserted into the headphone interface, determine whether the headphone is a PTT headphone, obtain a determination result, and transmit the determination result to the processor; The processor is configured to generate a control signal according to the determination result and transmit the control signal to the channel switch; The channel switch is configured to switch between a first channel and a second channel in the channel switch according to the control signal to be compatible with the PTT headphone.

2. The headphone compatibility circuit according to claim 1, wherein The audio codec is specifically configured to, when detecting that the headphone is inserted into the headphone interface, detect the magnitude relationship between the impedance of the right headphone in the headphone and a preset impedance to obtain the determination result; if the impedance of the right headphone in the headphone is greater than the preset impedance, the determination result indicates that the headphone is the PTT headphone; If the impedance of the right headphone in the headphone is less than the preset impedance, the determination result indicates that the headphone is a CTIA headphone or an OMTP headphone.

3. The headphone compatibility circuit according to claim 2, wherein The processor is specifically configured to control the level of the control signal to be a first level when the determination result indicates that the headphone is the PTT headphone; or control the level of the control signal to be a second level when the determination result indicates that the headphone is a CTIA headphone or an OMTP headphone.

4. The headphone compatibility circuit according to claim 3, wherein The channel switch is specifically configured to switch from the first channel to the second channel when the level of the control signal is the first level, or switch to the first channel when the level of the control signal is the second level.

5. The headphone compatibility circuit according to any one of claims 1-4, characterized in that The headphone compatibility circuit further includes: a voltage dividing circuit; The control end of the voltage dividing circuit is used to access a driving signal. The first end of the voltage dividing circuit is used to access a first voltage. The second end of the voltage dividing circuit is electrically connected between the third end of the channel switch and the headphone interface; The voltage dividing circuit is configured to conduct according to the driving signal when the PTT headphone is inserted into the headphone interface to change the potential of the headphone interface; The processor is further configured to detect the potential of the headphone interface to determine whether the button of the PTT headphone is in a released state. If it is detected that the potential of the headphone interface is the second level, it is determined that the button of the PTT headphone is in a released state; if it is detected that the potential of the headphone interface is the first level, it is determined that the button is not in a released state.

6. The headphone compatibility circuit according to claim 5, wherein The voltage dividing circuit includes: a first voltage dividing resistor, a second voltage dividing resistor, a third voltage dividing resistor, and a DIP switch; The first ends of the first voltage dividing resistor, the second voltage dividing resistor, and the third voltage dividing resistor are all used to connect to the first voltage. The second ends of the first voltage dividing resistor, the second voltage dividing resistor, and the third voltage dividing resistor are all electrically connected to the first end of the DIP switch. The control end of the DIP switch is used to connect to the drive signal. The second end of the DIP switch is electrically connected between the third end of the channel switcher and the headphone jack.

7. The headphone compatibility circuit according to claim 6, wherein The right earphone in the PTT earphone includes: the button, a first resistor, and a second resistor; The first resistor and the second resistor are connected in parallel. The second resistor is connected in series with the button. The second resistor and the button connected in series are electrically connected to the right interface in the headphone jack.

8. The headphone compatibility circuit according to claim 7, wherein When the resistance value of the first resistor is 4.7 KΩ and the resistance value of the second resistor is 2.1 KΩ, the resistance value of the first voltage dividing resistor is 9.6 KΩ; Or, when the resistance value of the first resistor is 6.8 KΩ and the resistance value of the second resistor is 2.1 KΩ, the resistance value of the second voltage dividing resistor is 12.5 KΩ; Or, when the resistance value of the first resistor is 9.1 KΩ and the resistance value of the second resistor is 2.1 KΩ, the resistance value of the third voltage dividing resistor is 15.6 KΩ.

9. The headphone compatibility circuit according to any one of claims 1-4, characterized in that, The channel switcher includes: a third resistor and a single-pole double-throw switch; The first end of the third resistor is electrically connected to the second end of the processor. The second end of the third resistor is electrically connected to the enable end of the single-pole double-throw switch. The common end of the single-pole double-throw switch is electrically connected to the audio codec. The normally open end of the single-pole double-throw switch is electrically connected to the headphone jack.

10. A portable terminal device, characterized in that, The portable terminal device includes: the headphone compatibility circuit according to any one of claims 1-9.

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