Mobile device and headphone plugging and unplugging noise elimination method

Abstract

The present application provides a mobile device and a method for eliminating headphone plug-in noise, the method comprising: detecting whether a headphone plug is inserted into a headphone socket; if a headphone plug is inserted into the headphone socket, first disabling the discharge circuit of the microphone pin, and then turning on the headphone bias voltage; obtaining the voltage signal on the microphone pin, and identifying the type of the headphone plug according to the obtained voltage signal; after completing the identification of the type of the headphone plug, enabling the discharge circuit. When the method detects that a headphone plug is inserted, by first disabling the discharge circuit and then turning on the headphone bias voltage, the microphone pin can be prevented from being repeatedly powered on and discharged during the insertion and identification process of the headphone plug, thereby avoiding the generation of fluctuating voltage in the left and right channel circuits and causing current noise; by re-enabling the discharge circuit after completing the headphone plug identification, the microphone pin can be discharged immediately when the headphone plug is unplugged, thereby avoiding the generation of unplugging noise during the unplugging process of the headphone plug.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a mobile device and a method for eliminating noise when plugging and unplugging an earphone. Background Art

[0002] With the popularization of smart mobile devices (such as smart phones, tablets, etc.) and the development of electronic technology, more and more functions are loaded on mobile devices. It has become an indispensable part of leisure life for users to play audio files or video files on mobile devices, so the use of headphones has also increased. At the same time, the headphone mode is also loved by users because of its delicate and realistic sound quality. In many cases, users will use the headphone playback mode, on the one hand, they can enjoy better sound quality, on the other hand, they can avoid affecting others.

[0003] With the increasing popularity of audio and video multimedia technology and consumers' increasing demands for quality, more stringent requirements have been put forward for headphone audio design. However, during the plugging and unplugging of headphones, noise often comes out from the left or right channel of the headphones, causing auditory discomfort to users. If the noise amplitude is large, it will also affect the user's hearing, thereby affecting the user experience. Summary of the invention

[0004] The purpose of the present application is to provide a mobile device and a method for eliminating headphone plugging and unplugging noise, so as to solve the technical problem in the prior art that the headphone plug generates noise during the plugging and unplugging process.

[0005] In order to solve the above technical problems, the first aspect of the present application provides a mobile device, which includes a headphone socket, a headphone bias voltage circuit, a discharge circuit and a controller. A microphone pin is arranged in the headphone socket. The headphone bias voltage circuit is electrically connected to the microphone pin, and the microphone pin receives the headphone bias voltage through the headphone bias voltage circuit. The discharge circuit is electrically connected to the microphone pin, and the discharge circuit is used to provide a discharge path for the microphone pin in a conductive state. The controller is used to disable the discharge circuit first, then turn on the headphone bias voltage, and then obtain the voltage signal on the microphone pin when detecting that a headphone plug is inserted into the headphone socket, and identify the type of the headphone plug according to the obtained voltage signal, and enable the discharge circuit after completing the type identification of the headphone plug.

[0006] The mobile device provided in the present application, when detecting that a headphone plug is inserted, can prevent the microphone pin from being repeatedly powered on and discharged during the insertion and identification process of the headphone plug by first disabling the microphone pin discharge circuit (i.e., turning off the quick discharge function of the microphone pin) and then turning on the headphone bias voltage, thereby avoiding the generation of fluctuating voltage in the left and right channel circuits and causing current noise; by re-enabling the discharge circuit (i.e., turning on the quick discharge function of the microphone pin) after the headphone plug identification process is completed, the microphone pin can be discharged immediately when the headphone plug is unplugged, thereby avoiding the generation of unplugging noise during the unplugging process of the headphone plug.

[0007] In a possible implementation of the first aspect, the headphone socket is further provided with a left channel pin, a right channel pin, a ground pin, and a left detection pin. The mobile device further includes a headphone plug-in noise elimination circuit, the headphone plug-in noise elimination circuit includes the discharge circuit, a detection module, and a logic control module, the detection module is used to detect the voltage on the left detection pin and the right channel pin, and output a corresponding detection signal. The logic control module is electrically connected to the detection module and the discharge circuit, respectively, and the logic control module generates a corresponding logic control signal based on the detection signal output by the detection module to turn on or off the discharge circuit in an enabled state.

[0008] In a possible implementation of the first aspect, the logic control signal includes a first logic signal and a second logic signal, wherein the logic control module is used to generate the first logic signal when the detection module detects that the voltage on the left detection pin or the voltage on the right channel pin is at a high level, and the first logic signal is used to turn on the discharge circuit in an enabled state, so that the microphone pin discharges through the discharge circuit, that is, the discharge circuit provides a fast discharge path for the microphone pin. It can be understood that the voltage on the left detection pin or the voltage on the right channel pin is at a high level, indicating that the headphone plug is not fully inserted into the headphone socket. Since the headphone bias voltage circuit is electrically connected to the microphone pin, the discharge circuit grounds the microphone pin, and the headphone bias voltage circuit is also electrically connected to the ground through the discharge circuit, that is, the discharge circuit provides a ground loop for the headphone bias voltage circuit, thereby preventing the headphone bias voltage circuit from transmitting the headphone bias voltage to the microphone pin.

[0009] The logic control module is also used to generate the second logic signal when the detection module detects that the voltage on the left detection pin and the voltage on the right channel pin are both at a low level. The second logic signal is used to disconnect the discharge circuit in the enabled state, so that the headphone bias voltage circuit can transmit the headphone bias voltage to the microphone pin, that is, to achieve the purpose of enabling the headphone bias voltage circuit. It can be understood that the voltage on the left detection pin and the voltage on the right channel pin are both at a low level, indicating that the headphone plug may have been fully inserted into the headphone socket.

[0010] In a possible implementation of the first aspect, the detection module includes a first detection module and a second detection module, the first detection module is used to detect the voltage on the left detection pin, and output a first detection signal based on a first reference voltage and the voltage on the left detection pin. The second detection module is used to detect the voltage on the right channel pin, and output a second detection signal based on a second reference voltage and the voltage on the right channel pin. The logic control module is electrically connected to the output ends of the first detection module and the second detection module, respectively, and the logic control module generates a corresponding logic control signal based on the first detection signal and the second detection signal to turn on or off the discharge circuit in an enabled state.

[0011] In a possible implementation manner of the first aspect, the controller is electrically connected to an output end of the logic control module, and the controller detects whether an earphone plug is inserted into the earphone socket based on a logic control signal generated by the logic control module.

[0012] In a possible implementation manner of the first aspect, an enable switch is further included which is electrically connected to the controller and the discharge circuit respectively, and the controller is configured to enable the discharge circuit by turning on the enable switch and disable the discharge circuit by turning off the enable switch;

[0013] Among them, the enable switch is electrically connected between the microphone pin and the discharge circuit. In this way, by turning on the enable switch, the discharge circuit can be electrically connected to the microphone pin, thereby achieving the purpose of enabling the discharge circuit; by turning off the enable switch, the discharge circuit can be electrically disconnected from the microphone pin, thereby achieving the purpose of disabling the discharge circuit.

[0014] Optionally, the enabling switch is electrically connected between the output end of the logic control module and the discharge circuit. Thus, by turning on the enabling switch, the discharge circuit can be electrically connected to the output end of the logic control module, so that the logic control signal output by the logic control module can turn on or off the discharge circuit, thereby achieving the purpose of enabling the discharge circuit; by turning off the enabling switch, the discharge circuit can be electrically disconnected from the output end of the logic control module, so that the logic control signal output by the logic control module cannot control the on / off state of the discharge circuit, thereby achieving the purpose of disabling the discharge circuit.

[0015] In a possible implementation of the first aspect, the axial depth of the left detection pin in the headphone socket is substantially equal to the axial depth of the left channel pin in the headphone socket, and when the external headphone plug is fully inserted into the headphone socket, the left detection pin contacts and is electrically connected to the left channel section of the externally inserted headphone plug. In this way, it can be ensured that the voltage on the left detection pin may change only when the headphone plug is inserted into the headphone socket and the left channel pin contacts the headphone plug.

[0016] In a possible implementation of the first aspect, the discharge circuit includes a ground terminal and a control switch connected in series between the ground terminal and the microphone pin, the control switch is used to turn on or off the discharge circuit, the control end of the control switch is electrically connected to the output end of the logic control module, and the logic control module generates a corresponding logic control signal based on the detection signal output by the detection module to turn on or off the control switch.

[0017] The second aspect of the present application provides a headphone plug-in noise elimination method, which is applied to the mobile device described in the first aspect, and the headphone plug-in noise elimination method includes: detecting whether a headphone plug is inserted into the headphone socket; if it is detected that a headphone plug is inserted into the headphone socket, first disabling the discharge circuit of the microphone pin, and then turning on the headphone bias voltage; obtaining the voltage signal on the microphone pin, and identifying the type of the headphone plug based on the obtained voltage signal on the microphone pin; after completing the identification of the type of the headphone plug, enabling the discharge circuit.

[0018] The headphone plug-in noise elimination method provided in the present application, when detecting that a headphone plug is inserted, first disables the discharge circuit of the microphone pin (i.e., turns off the fast discharge function of the microphone pin) and then turns on the headphone bias voltage. This can prevent the microphone pin from being repeatedly powered on and discharged during the insertion and identification process of the headphone plug, thereby avoiding the generation of fluctuating voltage in the left and right channel circuits and causing current noise. By re-enabling the discharge circuit (i.e., turning on the fast discharge function of the microphone pin) after the headphone plug identification process is completed, the microphone pin can be discharged immediately when the headphone plug is unplugged, thereby avoiding the generation of unplugging noise during the unplugging process of the headphone plug.

[0019] In a possible implementation of the second aspect, identifying the type of the headphone plug according to the voltage signal obtained on the microphone pin includes: determining whether the voltage value of the voltage signal obtained on the microphone pin is less than the first preset threshold; if the voltage value of the voltage signal on the microphone pin is less than the first preset threshold, identifying the headphone plug as a three-stage headphone plug; if the voltage value of the voltage signal on the microphone pin is greater than or equal to the first preset threshold, continuing to determine whether the voltage value of the voltage signal on the microphone pin is less than a second preset threshold; if the voltage value of the voltage signal on the microphone pin is less than the second preset threshold, identifying the headphone plug as a four-stage headphone plug; if the voltage value of the voltage signal on the microphone pin is greater than or equal to the second preset threshold, identifying the headphone plug as a three-stage headphone plug. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the implementation methods of the present application, the drawings required for use in the description of the implementation methods will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a schematic diagram of the structure of a conventional mobile device, wherein the mobile device comprises an earphone socket for inserting an external earphone plug.

[0022] Figure 2 The figure is a flow chart of a conventional headphone plug identification method.

[0023] Figure 3 This is a structural schematic diagram of a mobile device provided in the first embodiment of the present application, wherein the mobile device comprises an earphone socket for inserting an external earphone plug, and the earphone plug in the earphone socket is in a first insertion state.

[0024] Figure 4A schematic diagram of the structure of a mobile device provided in the second embodiment of the present application.

[0025] Figure 5 for Figure 3 The schematic diagram shown is a headphone plug in a second insertion state, wherein the mobile device is in a standby mode.

[0026] Figure 6 for Figure 3 The schematic diagram shown is a headphone plug in a second insertion state, wherein the mobile device is in an audio playback mode.

[0027] Figure 7 A flowchart of a headphone plug-in noise elimination method provided in an embodiment of the present application.

[0028] Figure 8 for Figure 7 A detailed flowchart of step 75 in the flowchart shown.

[0029] Main component symbols

[0030]

[0031]

[0032] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. The drawings are only for illustrative purposes and represent only schematic diagrams, which cannot be understood as limitations on the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art. The terms used in this application in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] Earphones (Earphones, Headphones, Head-sets, Earpieces) are a pair of conversion units that receive electrical signals from media players (such as smart phones, tablets, Walkman and other mobile devices) and convert them into audible sound waves using speakers close to the ears. Earphones can be separated from the media player and connected with only one plug, so that you can listen to music alone without disturbing others; they can also isolate the sounds of the surrounding environment, which is very helpful for users who use media players in noisy environments such as recording studios, bars, travel, and sports.

[0036] For wired headphones, when the headphone plug is inserted into the headphone socket on the mobile device, the mobile device usually needs to identify the headphone plug before normal data transmission. Specifically, take a four-section headphone plug and a corresponding conventional headphone socket as an example. Figure 1 As shown, the headphone plug 200 includes a left channel segment L, a right channel segment R, a ground segment GND and a microphone segment MIC, and each segment is connected by an insulating ring (such as Figure 1 The left channel segment L is electrically connected to the ground segment GND through a resistor R21, and the right channel segment R is electrically connected to the ground segment GND through a resistor R22. The resistors R21 and R22 are equivalent resistors of the internal load of the earphone, and have a small impedance value. Correspondingly, a left channel pin 1, a right channel pin 2, a ground pin 3, and a microphone pin 4 are provided in the earphone socket 10. The positions of the left channel pin 1, the right channel pin 2, the ground pin 3, and the microphone pin 4 in the earphone socket 10 are set to: when an external earphone plug 200 matching the earphone socket 10 is fully inserted into the earphone socket 10, the left channel segment L, the right channel segment R, the ground segment GND, and the microphone segment MIC of the externally inserted earphone plug 200 are in one-to-one contact and electrically connected.

[0037] Inside the mobile device 100', the left channel pin 1 is also grounded through an internal pull-down resistor (not shown) in the left channel circuit, and the pull-down resistor can be a resistor device with a relatively small resistance value. The microphone pin 4 is electrically connected to the headphone bias voltage circuit 40 and the discharge circuit 301, respectively, wherein the microphone pin 4 receives the headphone bias voltage Head_Micbias through the headphone bias voltage circuit 40, so that after the headphone plug 200 of the external headphone is inserted into the headphone socket 10, the controller 20 can correctly identify the type of the headphone plug 200, for example, whether the headphone plug 200 is a three-stage or four-stage headphone plug. The headphone bias voltage Head_Micbias can be provided by the controller 20 and transmitted to the microphone pin 4 through the headphone bias voltage circuit 40. The headphone bias voltage circuit 40 may include a resistor R41 electrically connected between the controller 20 and the microphone pin 4. The discharge circuit 301 is used to provide a discharge path for the microphone pin 4 in the on state. It is understandable that transmitting the headphone bias voltage Head_Micbias to the microphone pin 4 through the headphone bias voltage circuit 40 will increase the voltage on the microphone pin 4; and the microphone pin 4 discharges through the discharge circuit 301, which can reduce the voltage on the microphone pin 4.

[0038] In order to realize the plug-in and unplug identification of the headphone plug 200, a left detection pin 5 is further provided in the headphone socket 10, wherein the axial depth of the left detection pin 5 in the headphone socket 10 is approximately equal to the axial depth of the left channel pin 1 in the headphone socket 10, and when the external headphone plug 200 is fully inserted into the headphone socket 10, the left detection pin 5 contacts and is electrically connected with the left channel segment L of the externally inserted headphone plug 200. In this way, it can be ensured that the voltage on the left detection pin 5 may change only when the headphone plug 200 is inserted into the headphone socket 10 and the left channel pin 1 contacts the headphone plug 200. It should be noted that the "approximately equal" defined in this application means approximately equal, not limited to absolute equality, and includes a relationship that is not absolutely equal due to factors such as design tolerance and the influence of structural flatness.

[0039] It is understandable that the "pin" mentioned in this application can be embodied as a metal contact, a metal spring, etc. in terms of physical structure, and this application does not specifically limit the physical structure of the pin. The "axial depth" of the pin in the headphone socket mentioned in this application refers to the axial distance from the opening end of the headphone socket to the setting position of the pin.

[0040] Figure 21 is a flow chart of a conventional headphone plug identification method. The identification method can be applied to a mobile device 100', and includes the following steps:

[0041] Step 21, detect whether an earphone plug is inserted into the earphone socket. If it is detected that an earphone plug is inserted into the earphone socket, execute step 22. Otherwise, return to step 21 and continue to detect whether an earphone plug is inserted into the earphone socket.

[0042] Specifically, in one implementation, when the headphone plug 200 is inserted into the headphone socket 10, and the left channel segment L of the headphone plug 200 short-circuits the left detection pin 5 and the left channel pin 1, it is possible to determine whether the headphone plug 200 is inserted into the headphone socket 10 by detecting the voltage on the left detection pin 5 of the headphone socket 10. When the voltage on the left detection pin 5 is at a low level, it can be determined that the headphone plug 200 is inserted into the headphone socket 10.

[0043] In another embodiment, if Figure 1 As shown, when the headphone plug 200 is inserted into the headphone socket 10, and the left channel segment L of the headphone plug 200 short-circuits the left detection pin 5 and the left channel pin 1, and the right channel segment R of the headphone plug 200 short-circuits the right channel pin 2, it is possible to determine whether the headphone plug 200 is inserted into the headphone socket 10 by detecting the voltages on the left detection pin 5 and the right channel pin 2 of the headphone socket 10. When the voltages on the left detection pin 5 and the right channel pin 2 are both at low levels, it can be determined that the headphone plug 200 is inserted into the headphone socket 10.

[0044] Step 22, turning on the headphone bias voltage.

[0045] Step 23 , obtaining a voltage signal on the microphone pin of the headphone socket 10 .

[0046] Step 24, determining whether the voltage value of the voltage signal on the microphone pin is less than a preset threshold value. If the voltage value of the voltage signal on the microphone pin is less than the preset threshold value, executing step 25. Otherwise, executing step 26.

[0047] The preset threshold value may be set to 0.1V, and the present application does not impose any specific limitation on the specific value of the preset threshold value.

[0048] Step 25: Identify the headphone plug as a three-section headphone plug.

[0049] Step 26: Identify the headphone plug as a four-section headphone plug.

[0050] In the identification method, the controller of the mobile device may turn on the headphone bias voltage Head_Micbias, and identify the type of the headphone plug 200 according to the voltage value on the microphone pin 4 of the headphone socket 10 .

[0051] However, using Figure 1 The earphone jack 10 structure shown and Figure 2 Although the identification method shown can identify the insertion of the headphone plug 200, it cannot accurately identify whether the headphone plug 200 is fully inserted into the headphone socket 10. Figure 2 The identification method shown is to turn on the headphone bias voltage Head_Micbias when the headphone plug 200 is identified to be inserted, so that noise is often transmitted from the left channel or the right channel of the headphone during the process of inserting the headphone plug 200 into the headphone socket 10 or removing the headphone plug 200 from the headphone socket 10. In particular, during the slow insertion of the headphone plug 200, continuous current noise is generated due to repeated power-on and rapid discharge of the microphone pin 4, causing auditory discomfort to the user. If the noise amplitude is large, it will also affect the user's hearing, thereby affecting the user experience.

[0052] Specifically, for example Figure 1As shown, when the headphone plug 200 is not fully inserted, but the left channel segment L of the headphone plug 200 short-circuits the left channel pin 1 and the left detection pin 5 of the headphone socket 10, and the right channel segment R of the headphone plug 200 short-circuits the right channel pin 2, the controller 20 of the mobile device 100' detects that the voltages on the left detection pin 5 and the right channel pin 2 are both low-level signals, and therefore determines that the headphone plug 200 is inserted. At this time, the controller 20 turns on the headphone bias voltage Head_Micbias, thereby increasing the voltage on the microphone pin 4 of the headphone socket 10. Since the microphone pin 4 of the headphone jack 10 contacts the microphone section MIC of the headphone plug 200, and the ground pin 3 of the headphone jack 10 contacts the insulating ring of the headphone plug 200 and is disconnected, the headphone bias voltage Head_Micbias applied to the microphone pin 4 will enter the left and right channel circuits through the microphone section MIC of the headphone plug 200, the internal circuit of the headphone, and the left channel section L and the right channel section R of the headphone plug 200, respectively, causing the voltage on the left detection pin 5 and the right channel pin 2 of the headphone jack 10 to rise above the preset threshold, thereby triggering the microphone to be turned on. The microphone pin 4 is quickly discharged; and the microphone pin 4 quickly discharges the voltage on the left detection pin 5 and the right channel pin 2 of the headphone jack 10 again to below the preset threshold, thereby triggering the shutdown of the microphone pin 4. After the microphone pin 4 is shut down, the microphone pin 4 is powered on again, and the headphone bias voltage Head_Micbias enters the left and right channel circuits respectively again, causing the voltage on the left detection pin 5 and the right channel pin 2 of the headphone jack 10 to rise above the preset threshold again, thereby triggering the microphone pin 4 to quickly discharge again. The microphone pin 4 is repeatedly powered on and discharged in this way, which will cause a fluctuating voltage to appear in the left and right channel circuits, thereby generating current noise, especially in the slow plugging process of the headphone plug, the continuous current noise heard at the headphone end is more obvious. The unplugging noise is mainly generated because the controller 20 does not immediately cut off the headphone bias voltage Head_Micbias when the headphone plug enters the unplugging timing sequence, causing the headphone bias voltage Head_Micbias to be connected to the left and right channel circuits and generate current noise. The higher the headphone bias voltage Head_Micbias is, the greater the noise generated during the plugging and unplugging of the headphone plug will be.

[0053] In order to solve the technical problem that the headphone plug generates noise during the plugging and unplugging process in the prior art, Figure 3 As shown, the present application provides a mobile device 100 capable of eliminating earphone plugging and unplugging noise. The mobile device 100 includes but is not limited to electronic products such as smart phones, tablet computers, walkmans, and cars.

[0054] In this embodiment, the mobile device 100 includes an earphone socket 10, a controller 20, an earphone plug-in noise elimination circuit 30, and an earphone bias voltage circuit 40, wherein: Figure 3 The headphone jack 10 and the headphone bias voltage circuit 40 are respectively connected to Figure 1 The earphone socket 10 shown in the figure and the earphone bias voltage circuit 40 have the same structure.

[0055] The headphone plug-in noise elimination circuit 30 includes the discharge circuit 301. In the present embodiment, the controller 20 is used to disable the discharge circuit 301 first, then turn on the headphone bias voltage Head_Micbias, and then obtain the voltage signal on the microphone pin 4 when detecting that the headphone plug 200 is inserted into the headphone socket 10, and then identify the type of the headphone plug 200 according to the obtained voltage signal, and enable the discharge circuit 301 after completing the type identification of the headphone plug 200.

[0056] The mobile device 100 provided in the present application, when detecting that a headphone plug 200 is inserted, first disables the microphone pin 4 discharge circuit 301 (i.e., turns off the fast discharge function of the microphone pin 4), and then turns on the headphone bias voltage Head_Micbias. This can prevent the microphone pin 4 from being repeatedly powered on and discharged during the insertion and identification process of the headphone plug 200, thereby avoiding the generation of fluctuating voltage in the left and right channel circuits and causing current noise; by re-enabling the discharge circuit 301 (i.e., turning on the fast discharge function of the microphone pin 4) after the identification process of the headphone plug 200 is completed, the microphone pin 4 can be discharged immediately when the headphone plug 200 is unplugged, thereby avoiding the generation of unplugging noise during the unplugging process of the headphone plug 200.

[0057] Specifically, the headphone plug-in noise elimination circuit 30 also includes a detection module 302 and a logic control module 303. The detection module 302 is used to detect the voltage on the left detection pin 5 and the right channel pin 2, and output a corresponding detection signal. The logic control module 303 is electrically connected to the detection module 302 and the discharge circuit 301, respectively, and the logic control module 303 generates a corresponding logic control signal based on the detection signal output by the detection module 302 to turn on or off the discharge circuit 301 in the enabled state.

[0058] In this embodiment, the discharge circuit 301 includes a ground terminal GND and a control switch Q3 connected in series between the ground terminal GND and the microphone pin 4, and the control switch Q3 is used to turn on or off the discharge circuit 301. The control end of the control switch Q3 is electrically connected to the output end of the logic control module 303, and the logic control module 303 generates a corresponding logic control signal based on the detection signal output by the detection module 302 to turn on or off the control switch Q3, thereby turning on or off the discharge circuit 301 in the enabled state. In other words, the discharge circuit 301 and the logic control module 303 together constitute the enable control circuit of the headphone bias voltage circuit 40. In this embodiment, the control switch Q3 is in a normally open state.

[0059] In this embodiment, the logic control signal includes a first logic signal and a second logic signal. The logic control module 303 is used to generate the first logic signal when the detection module 302 detects that the voltage on the left detection pin 5 or the voltage on the right channel pin 2 is at a high level. The first logic signal is used to turn on the control switch Q3, thereby turning on the discharge circuit 301 in the enabled state, so that the microphone pin 4 discharges through the discharge circuit 301, that is, the discharge circuit 301 provides a fast discharge path for the microphone pin 4. It can be understood that the voltage on the left detection pin 5 or the voltage on the right channel pin 2 is at a high level, indicating that the headphone plug 200 is not fully inserted into the headphone socket 10. Since the headphone bias voltage circuit 40 is electrically connected to the microphone pin 4, while the discharge circuit 301 grounds the microphone pin 4, the headphone bias voltage circuit 40 is also electrically connected to the ground through the discharge circuit 301, that is, the discharge circuit 301 provides a grounding loop for the headphone bias voltage circuit 40, thereby preventing the headphone bias voltage circuit 40 from transmitting the headphone bias voltage Head_Micbias to the microphone pin 4.

[0060] The logic control module 303 is also used to generate the second logic signal when the detection module 302 detects that the voltage on the left detection pin 5 and the voltage on the right channel pin 2 are both low levels. The second logic signal is used to disconnect the control switch Q3, thereby disconnecting the discharge circuit 301 in the enabled state, so that the headphone bias voltage circuit 40 can transmit the headphone bias voltage Head_Micbias to the microphone pin 4, that is, to achieve the purpose of enabling the headphone bias voltage circuit 40. It can be understood that the voltage on the left detection pin 5 and the voltage on the right channel pin 2 are both low levels, indicating that the headphone plug 200 may have been fully inserted into the headphone socket 10.

[0061] In this embodiment, the controller 20 is electrically connected to the output end of the logic control module 303, and the controller 20 identifies the plug-in and unplug-out status of the external headphone plug 200 and controls the on and off of the headphone bias voltage Head_Micbias based on the logic control signal generated by the logic control module 303. Specifically, the controller 20 turns on the headphone bias voltage Head_Micbias when it is identified based on the logic control signal generated by the logic control module 303 that a headphone plug is inserted into the headphone socket 10, and turns off the headphone bias voltage Head_Micbias in time when it is identified based on the logic control signal that the headphone plug 200 is unplugged.

[0062] In order to enable and disable the discharge circuit 301, the mobile device 100 also includes an enable switch Q4 electrically connected to the controller 20 and the discharge circuit 301, respectively. The controller 20 is used to enable the discharge circuit 301 by turning on the enable switch Q4, and to disable the discharge circuit 301 by turning off the enable switch Q4.

[0063] Wherein, in one embodiment, Figure 3 As shown, the enabling switch Q4 can be electrically connected between the microphone pin 4 and the discharge circuit 301. Specifically, the control end of the enabling switch Q4 is electrically connected to the controller 20 to achieve the on-off control of the enabling switch Q4 by the controller 20. In this way, by turning on the enabling switch Q4, the discharge circuit 301 can be electrically connected to the microphone pin 4, thereby achieving the purpose of enabling the discharge circuit 301; by turning off the enabling switch Q4, the discharge circuit 301 can be electrically disconnected from the microphone pin 4, thereby achieving the purpose of disabling the discharge circuit 301. Among them, the enabling switch Q4 can be a transistor, such as a MOS tube, and the present application does not specifically limit the type of the enabling switch Q4.

[0064] Alternatively, in another embodiment, Figure 4As shown, the enabling switch Q4 can be electrically connected between the output end of the logic control module 303 and the discharge circuit 301. Specifically, the control end of the enabling switch Q4 is electrically connected to the controller 20 to realize the on-off control of the enabling switch Q4 by the controller 20. The enabling switch Q4 can be electrically connected between the output end of the logic control module 303 and the control end of the control switch Q3. In this way, by turning on the enabling switch Q4, the discharge circuit 301 can be electrically connected to the output end of the logic control module 303, so that the logic control signal output by the logic control module 303 can turn on or off the discharge circuit 301, thereby achieving the purpose of enabling the discharge circuit 301; by turning off the enabling switch Q4, the discharge circuit 301 can be electrically disconnected from the output end of the logic control module 303, so that the logic control signal output by the logic control module 303 cannot control the on-off state of the discharge circuit 301, thereby achieving the purpose of disabling the discharge circuit 301.

[0065] Please refer again Figure 3 In this embodiment, the detection module 302 includes a first detection module 31 and a second detection module 32, wherein the first detection module 31 is used to detect the voltage on the left detection pin 5, and output a first detection signal based on the first reference voltage and the voltage on the left detection pin 5. The second detection module 32 is used to detect the voltage on the right channel pin 2, and output a second detection signal based on the second reference voltage and the voltage on the right channel pin 2. That is, the second detection module 32 multiplexes the right channel pin 2 in the headphone socket 10 as the right detection pin.

[0066] The logic control module 303 is electrically connected to the output ends of the first detection module 31 and the second detection module 32 respectively. The logic control module 303 generates corresponding logic control signals based on the first detection signal and the second detection signal to turn on or off the discharge circuit 301 in the enabled state.

[0067] The specific structures of the first detection module 31 , the second detection module 32 and the logic control module 303 are introduced below.

[0068] The first detection module 31 includes a first pull-up resistor R31 and a first comparison unit 311, wherein the first pull-up resistor R31 is electrically connected between the left detection pin 5 and the first pull-up power supply VDD1, and a first connection node P1 is formed on the connection circuit between the first pull-up resistor R31 and the left detection pin 5. The first comparison unit 311 includes an input end electrically connected to the first connection node P1 and the input end of the first reference voltage, respectively, and an output end electrically connected to the input end of the enable control module 34. In this embodiment, the voltage on the first connection node P1 is substantially equal to the voltage on the left detection pin 5. The first comparison unit 311 outputs the first detection signal to the input end of the enable control module 34 based on the first reference voltage and the voltage on the left detection pin 5.

[0069] When the headphone plug 200 is fully inserted into the headphone socket 10, the left channel section L of the headphone plug 200 will short-circuit the left channel pin 1 and the left detection pin 5 of the headphone socket 10, so that the voltages on the left channel pin 1 and the left detection pin 5 are equal, and when the mobile device 100 is in two different usage modes, namely, the standby mode and the audio playback mode, the voltage output on the left channel pin 1 is different, and the voltage output on the right channel pin 2 is also different, wherein the voltages of the left channel pin 1 and the right channel pin 2 in the standby mode are much lower than the voltages in the audio playback mode. Therefore, the controller 20 will misjudge the state of the headphone plug 200 in the audio playback mode as the unplugged state.

[0070] In order to accurately identify the unplugging operation of the headphone plug 200 when the mobile device 100 is in different usage modes, in this embodiment, the first reference voltage includes a first reference voltage Vref1 and a second reference voltage Vref2. The first comparison unit 311 includes a first comparator Comp1, a second comparator Comp2 and a first switch S1, the first input terminal of the first comparator Comp1 and the first input terminal of the second comparator Comp2 are both electrically connected to the first connection node P1, the second input terminal of the first comparator Comp1 is electrically connected to the input terminal of the first reference voltage Vref1, and the second input terminal of the second comparator Comp2 is electrically connected to the input terminal of the second reference voltage Vref2, wherein the voltage value of the first reference voltage Vref1 is not equal to the voltage value of the second reference voltage Vref2.

[0071] The first switch S1 is used to conduct the electrical connection between one of the output end of the first comparator Comp1 and the output end of the second comparator Comp2 and the input end of the enable control module 34. Specifically, when the mobile device 100 is not in the audio playback mode or the headphone plug 200 is not fully inserted into the headphone socket 10, the first switch S1 conducts the electrical connection between the output end of the first comparator Comp1 and the input end of the enable control module 34. When the mobile device 100 is in the audio playback mode and the headphone plug 200 is fully inserted into the headphone socket 10, the first switch S1 conducts the electrical connection between the output end of the second comparator Comp2 and the input end of the enable control module 34.

[0072] In this embodiment, the first input terminal of the first comparator Comp1 and the first input terminal of the second comparator Comp2 are both negative input terminals, and the second input terminal of the first comparator Comp1 and the second input terminal of the second comparator Comp2 are both positive input terminals. The voltage value of the first reference voltage Vref1 is less than the voltage value of the second reference voltage Vref2. The output voltage value of the first pull-up power supply VDD1 is respectively greater than the voltage value of the first reference voltage Vref1 and the voltage value of the second reference voltage Vref2. When the mobile device 100 is not in the audio playback mode or the headphone plug 200 is not fully inserted into the headphone socket 10, as described above, inside the mobile device, the left channel pin 1 is grounded through an internal pull-down resistor (not shown) in the left channel circuit, so that the voltage value on the left channel pin 1 is less than the voltage value of the first reference voltage Vref1; when the mobile device 100 is in the audio playback mode and the headphone plug 200 is fully inserted into the headphone socket 10, the audio signal in the left channel circuit will cause the voltage value on the left channel pin 1 to be greater than the voltage value of the first reference voltage Vref1 and less than the voltage value of the second reference voltage Vref2.

[0073] The structure of the second detection module 32 is similar to that of the first detection module 31. Specifically, the second detection module 32 includes a second pull-up resistor R32 and a second comparison unit 321, wherein the second pull-up resistor R32 is electrically connected between the right channel pin 2 and the second pull-up power supply VDD2, and a second connection node P2 is formed on the connection circuit between the second pull-up resistor R32 and the right channel pin 2. The second comparison unit 321 includes an input end electrically connected to the second connection node P2 and the input end of the second reference voltage, respectively, and an output end electrically connected to the input end of the enable control module 34. In this embodiment, the voltage on the second connection node P2 is substantially equal to the voltage on the right channel pin 2. The second comparison unit 321 outputs the second detection signal to the input end of the enable control module 34 based on the second reference voltage and the voltage on the right channel pin 2.

[0074] In order to accurately identify the unplugging operation of the headphone plug 200 when the mobile device 100 is in different usage modes, in this embodiment, the second reference voltage includes a third reference voltage Vref3 and a fourth reference voltage Vref4. The second comparison unit 321 includes a third comparator Comp3, a fourth comparator Comp4 and a second switch S2, the first input terminal of the third comparator Comp3 and the first input terminal of the fourth comparator Comp4 are both electrically connected to the second connection node P2, the second input terminal of the third comparator Comp3 is electrically connected to the input terminal of the third reference voltage Vref3, and the second input terminal of the fourth comparator Comp4 is electrically connected to the input terminal of the fourth reference voltage Vref4, wherein the voltage value of the third reference voltage Vref3 is not equal to the voltage value of the fourth reference voltage Vref4.

[0075] The second switch S2 is used to conduct the electrical connection between one of the output end of the third comparator Comp3 and the output end of the fourth comparator Comp4 and the input end of the enable control module 34. Specifically, when the mobile device 100 is not in the audio playback mode or the headphone plug 200 is not fully inserted into the headphone socket 10, the second switch S2 conducts the electrical connection between the output end of the third comparator Comp3 and the input end of the enable control module 34. When the mobile device 100 is in the audio playback mode and the headphone plug 200 is fully inserted into the headphone socket 10, the second switch S2 conducts the electrical connection between the output end of the fourth comparator Comp4 and the input end of the enable control module 34. It can be understood that the conduction state of the first switch S1 and the second switch S2 can be controlled by the control signal output by the controller 20, and this application does not make specific limitations on this.

[0076] In this embodiment, the first input terminal of the third comparator Comp3 and the first input terminal of the fourth comparator Comp4 are both negative input terminals, and the second input terminal of the third comparator Comp3 and the second input terminal of the fourth comparator Comp4 are both positive input terminals. The voltage value of the third reference voltage Vref3 is less than the voltage value of the fourth reference voltage Vref4. The output voltage value of the second pull-up power supply VDD2 is respectively greater than the voltage value of the third reference voltage Vref3 and the voltage value of the fourth reference voltage Vref4. When the headphone plug 200 is fully inserted into the headphone socket 10, if the mobile device 100 is not in the audio playback mode, since the right channel pin 2 is grounded through the right channel segment R, the headphone internal circuit, the ground terminal GND, and the ground pin 3, or is grounded through the right channel segment R, the headphone internal circuit, the left channel segment L, the left channel pin 1, and the internal pull-down resistor in the left channel circuit, the voltage value on the right channel pin 2 is less than the voltage value of the third reference voltage Vref3; when the mobile device 100 is in the audio playback mode and the headphone plug 200 is fully inserted into the headphone socket 10, the audio signal in the right channel circuit will make the voltage value on the right channel pin 2 greater than the voltage value of the third reference voltage Vref3 and less than the voltage value of the fourth reference voltage Vref4.

[0077] In one embodiment, the first pull-up resistor R31 and the second pull-up resistor R32 may have the same resistance value, for example, both have a resistance value of 1M ohm. The output voltage values ​​of the first pull-up power supply VDD1 and the second pull-up power supply VDD2 may be set to the same voltage value, for example, both are set to a voltage value of 2.8V. The first reference voltage Vref1 and the third reference voltage Vref3 may have the same voltage value, for example, both have a voltage value of 50mV. The second reference voltage Vref2 and the fourth reference voltage Vref4 may have the same voltage value, for example, both have a voltage value of 1.8V to 2V.

[0078] It should be noted that the above parameters are only example parameters of an implementation method for realizing the function of identifying the plug-in and unplug status of the headphone, but the values ​​of each pull-up resistor, pull-up power supply and reference voltage are not limited to the above parameters. Those skilled in the art can adaptively adjust or modify the values ​​of the pull-up resistor, pull-up power supply and reference voltage of each detection module, and the connection mode of the input terminal of each comparator according to actual design requirements to realize the identification of the plug-in and unplug status of the headphone. For example, in another implementation, the first pull-up resistor R31 and the second pull-up resistor R32 may also adopt different resistance values. Optionally, the output voltage values ​​of the first pull-up power supply VDD1 and the second pull-up power supply VDD2 may be set to different voltage values. Optionally, the first reference voltage Vref1 and the third reference voltage Vref3 may also adopt different voltage values. Optionally, the second reference voltage Vref2 and the fourth reference voltage Vref4 may also adopt different voltage values. All technical variations made according to the technical solution of the present application are covered within the protection scope of the present application.

[0079] The logic control module 303 includes input terminals electrically connected to the output terminals of the first detection module 31 and the second detection module 32. In this embodiment, the logic control module 303 uses a NAND gate G1, and the NAND gate G1 is used to perform an AND operation on the detection signals output by the first detection module 31 and the second detection module 32, and then perform a NOT operation, and finally output a corresponding logic control signal.

[0080] The control switch Q3 uses a transistor that is turned on at a high level, such as an NMOS tube. It is understandable that the headphone plug-in noise elimination circuit 30 realizes the function of quickly discharging the microphone pin 4 by connecting an NMOS tube in series to the discharge circuit 301, and can use the fast turn-on and turn-off speed characteristics of the transistor to quickly respond to the plug-in and pull-out status of the headphone plug 200, so that the headphone plug-in and pull-out noise can be eliminated more thoroughly.

[0081] It should be noted that in this embodiment, the logic control module 303 uses the NAND gate G1 and the control switch Q3 uses the high-level NMOS tube, which is only an example of an implementation method for realizing the control function of the headphone bias voltage Head_Micbias, but the logic control module 303 is not limited to using the NAND gate, and the control switch Q3 is not limited to using the high-level NMOS tube. Those skilled in the art can use one or more other types of logic control modules 303 to output corresponding logic control signals based on the detection signals output by the two detection modules, and use other types of switch tubes to control the on and off of the discharge circuit 301 according to actual design requirements, so as to realize the control function of the headphone bias voltage Head_Micbias. All technical variations made according to the technical solution of this application are covered within the protection scope of this application.

[0082] In one embodiment, the headphone plug-in noise elimination circuit 30 may be packaged in the form of a chip.

[0083] Below Figure 3 and Figure 5 Taking the circuit structure shown in FIG. 1 as an example, the working principle of the mobile device 100 to eliminate the headphone plug-in noise function is introduced. The truth tables of each detection pin, each comparator, NAND gate, headphone bias voltage and NMOS tube described in this application are shown in Table 1 below:

[0084] Table 1

[0085]

[0086] When the external earphone plug 200 is inserted into the earphone socket 10, Figure 3When the first comparator Comp1 is in the position shown, the first switch S1 keeps conducting the electrical connection between the output end of the first comparator Comp1 and the input end of the logic control module 303, and the second switch S2 keeps conducting the electrical connection between the output end of the third comparator Comp3 and the input end of the logic control module 303. The left channel segment L of the headphone plug 200 short-circuits the left channel pin 1 of the headphone socket 10 and the left detection pin 5, and the right channel segment R of the headphone plug 200 short-circuits the right channel pin 2 of the headphone socket 10. Therefore, the left detection pin 5 is grounded through the internal pull-down resistor (not shown) of the left channel pin 1, and the right channel pin 2 is grounded through the right channel segment R, the internal circuit of the headphone, the left channel segment L and the internal pull-down resistor of the left channel pin 1. Accordingly, the first comparator Comp1 and the third comparator Comp3 both output high-level signals. The NAND gate G1 outputs a low-level signal, i.e., the second logic signal, based on the high-level signals output by the first comparator Comp1 and the third comparator Comp3. The controller 20 recognizes that the headphone plug 200 is inserted into the headphone socket 10 according to the second logic signal. As described above, the controller 20 first turns off the enable switch Q4 to disable the discharge circuit 301, and then turns on the headphone bias voltage Head_Micbias to power on the microphone pin 4.

[0087] exist Figure 3In the position shown, since the microphone pin 4 of the headphone socket 10 contacts the microphone segment MIC of the headphone plug 200, and the ground pin 3 of the headphone socket 10 contacts the insulating ring of the headphone plug 200 and is disconnected, the headphone bias voltage Head_Micbias loaded on the microphone pin 4 enters the left and right channel circuits through the microphone segment MIC of the headphone plug 200, the internal circuit of the headphone, and the left channel segment L and the right channel segment R of the headphone plug 200, respectively, so that the voltage on the left detection pin 5 and the right channel pin 2 of the headphone socket 10 rises above the preset threshold value, and accordingly, the first comparator Comp1 and the third comparator Comp3 both output low-level signals. The NAND gate G1 outputs a high-level signal based on the low-level signals output by the first comparator Comp1 and the third comparator Comp3, that is, the first logic signal. At this time, although the NAND gate G1 outputs the first logic signal, the discharge circuit 301 has been disabled, so the first logic signal cannot be used to turn on the discharge circuit 301, thereby not triggering the rapid discharge of the microphone pin 4. At the same time, since the controller 20 continuously turns on the headphone bias voltage Head_Micbias after recognizing that the headphone plug 200 is inserted into the headphone socket 10, so that the microphone pin 4 remains powered on, although the voltages on the left detection pin 5 and the right channel pin 2 of the headphone socket 10 rise above the preset threshold, they are both kept in a relatively stable voltage state and no current noise is generated. In this way, the purpose of eliminating the insertion noise of the headphone plug can be achieved.

[0088] When the earphone plug 200 is further inserted into the earphone socket 10 and is located Figure 5 When the headphone plug 200 is in the position shown, that is, the headphone plug 200 is completely inserted into the headphone socket 10, the first switch S1 keeps conducting the electrical connection between the output end of the first comparator Comp1 and the input end of the logic control module 303, and the second switch S2 keeps conducting the electrical connection between the output end of the third comparator Comp3 and the input end of the logic control module 303. The microphone pin 4 of the headphone socket 10 contacts the microphone segment MIC of the headphone plug 200, and the ground pin 3 of the headphone socket 10 is electrically connected to the ground terminal GND of the headphone plug 200. Therefore, the headphone bias voltage Head_Micbias loaded on the microphone pin 4 is connected to the ground loop of the ground pin 3 through the microphone segment MIC of the headphone plug 200, the internal circuit of the headphone, and the ground segment GND of the headphone plug 200. That is to say, the headphone bias voltage Head_Micbias loaded on the microphone pin 4 will not enter the left and right channel circuits.

[0089] At the same time, Figure 5In the position shown, the left channel segment L of the headphone plug 200 short-circuits the left channel pin 1 of the headphone socket 10 and the left detection pin 5, and the right channel segment R of the headphone plug 200 short-circuits the right channel pin 2 of the headphone socket 10. Therefore, the voltages of the left detection pin 5 and the right channel pin 2 are both pulled down, and accordingly, the first comparator Comp1 and the third comparator Comp3 both output high-level signals. The NAND gate G1 outputs a low-level signal, i.e., the second logic signal, based on the high-level signals output by the first comparator Comp1 and the third comparator Comp3. As described above, it can be seen that after the controller 20 completes the type recognition of the headphone plug 200, it enables the discharge circuit 301 by turning on the enable switch Q4. At this time, the second logic signal can be used to disconnect the control switch Q3, thereby disconnecting the discharge circuit 301, so that the headphone bias voltage circuit 40 can continuously transmit the headphone bias voltage Head_Micbias to the microphone pin 4.

[0090] When the earphone plug 200 is fully inserted and stays in the earphone socket 10, if the mobile device 100 is in standby mode, such as Figure 5 As shown, the first switch S1 continues to maintain the electrical connection between the output end of the first comparator Comp1 and the input end of the logic control module 303, and the second switch S2 continues to maintain the electrical connection between the output end of the third comparator Comp3 and the input end of the logic control module 303. If the mobile device 100 is in the audio playback mode, such as Figure 6 As shown, the first switch S1 conducts the electrical connection between the output end of the second comparator Comp2 and the input end of the logic control module 303, and the second switch S2 conducts the electrical connection between the output end of the fourth comparator Comp4 and the input end of the logic control module 303. In this way, during the unplugging process of the headphone plug 200, different voltages are loaded on the left and right channel pins according to different usage modes of the mobile device 100, and the headphone plug-in noise elimination circuit 30 can also correctly identify the unplugging operation of the headphone plug 200.

[0091] When the earphone plug 200 is in a fully inserted state (eg Figure 6 Start pulling out from the position shown in the figure and locate Figure 3When the position shown in FIG. 1 is reached, since the microphone pin 4 is also loaded with the headphone bias voltage Head_Micbias, as described above, the headphone bias voltage Head_Micbias will enter the left and right channel circuits through the microphone segment MIC of the headphone plug 200, the internal circuit of the headphone, and the left channel segment L and the right channel segment R of the headphone plug 200, respectively, so that the voltage on the left detection pin 5 and the right channel pin 2 of the headphone socket 10 rises above the preset threshold value, and accordingly, the first comparator Comp1 and the third comparator Comp3 both output low-level signals. The NAND gate G1 outputs a high-level signal, i.e., the first logic signal, based on the low-level signals output by the first comparator Comp1 and the third comparator Comp3, so that the control switch Q3 is immediately turned on, thereby electrically connecting the microphone pin 4 to the ground for rapid discharge. At the same time, the controller 20 recognizes that the headphone plug 200 is unplugged according to the first logic signal, so the controller 20 turns off the headphone bias voltage Head_Micbias. In this way, the purpose of eliminating the unplugging noise of the headphone plug can be achieved.

[0092] It can be understood that if the mobile device 100 is in the audio playback mode before the headphone plug 200 is unplugged, when the controller 20 recognizes that the headphone plug 200 is unplugged, the controller 20 also controls the first switching switch S1 to conduct the electrical connection between the output end of the first comparator Comp1 and the input end of the logic control module 303, and controls the second switching switch S2 to conduct the electrical connection between the output end of the third comparator Comp3 and the input end of the logic control module 303.

[0093] When the headphone plug 200 is unplugged from a fully inserted state, since there is residual charge on the microphone pin 4, the headphone plug-in noise elimination circuit 30 of the present application electrically connects the microphone pin 4 to the ground by setting the discharge circuit 301, and can quickly respond to the unplugging operation of the headphone plug 200 from the hardware to quickly discharge the microphone pin 4, thereby completely eliminating the unplugging noise of the headphone plug 200.

[0094] Furthermore, in the process of unplugging the external headphone plug 200 from the fully inserted state, since the controller 20 first needs to obtain relevant detection signals, such as the logic control signal output by the logic control module 303 to perform plug-in identification, it is impossible to immediately respond to the unplugging operation of the headphone plug 200 and immediately turn off the headphone bias voltage Head_Micbias. In addition, when the controller 20 fails, it is also impossible to immediately respond to the unplugging operation and immediately turn off the headphone bias voltage Head_Micbias, thereby causing unplugging noise. In view of this problem, the headphone plug-in noise elimination circuit 30 of the present application can quickly respond to the unplugging operation of the headphone plug 200 from the hardware by providing a discharge circuit 301 including a switch tube to quickly discharge the microphone pin 4, thereby effectively avoiding the noise caused by the slow software control response speed of the controller 20 and the inability to immediately respond to the unplugging operation, that is, effectively avoiding the unplugging noise caused by cutting off the headphone bias voltage Head_Micbias too late when the headphone plug 200 is unplugged.

[0095] It should be noted that the Figure 3-Figure 6 The illustrated embodiment takes a four-stage American standard plug structure and a corresponding headphone socket 10 structure as an example to introduce the related structure for eliminating headphone plugging noise included in the mobile device 100 provided by the present application. It can be understood by those skilled in the art that the related structure for eliminating headphone plugging noise in the present application is also applicable to a four-stage European standard plug structure and a corresponding headphone socket structure. In practical applications, those skilled in the art only need to adjust the setting positions of the ground pin 3 and the microphone pin 4 in the headphone socket according to the positions of the ground segment GND and the microphone segment MIC of the headphone plug 200.

[0096] See also Figure 7 The present application also provides a method for eliminating earphone plugging and unplugging noise, wherein the method can be applied to the mobile device 100 mentioned above. Figure 7 As shown, the method comprises the following steps:

[0097] Step 71, detect whether an earphone plug is inserted into the earphone socket. If it is detected that an earphone plug is inserted into the earphone socket, execute step 72. Otherwise, return to step 71 and continue to detect whether an earphone plug is inserted into the earphone socket.

[0098] Step 72, disable the discharge circuit of the microphone pin.

[0099] Step 73, turning on the headphone bias voltage.

[0100] Step 74, obtaining the voltage signal on the microphone pin.

[0101] Step 75: Identify the type of the headphone plug according to the acquired voltage signal on the microphone pin.

[0102] Among them, Figure 8 As shown, the step 75 may specifically include:

[0103] Step 751, determine whether the voltage value of the voltage signal on the microphone pin is less than a first preset threshold. If the voltage value of the voltage signal on the microphone pin is less than the first preset threshold, execute step 752. If the voltage value of the voltage signal on the microphone pin is greater than or equal to the first preset threshold, execute step 753.

[0104] Step 752: Identify the headphone plug as a three-section headphone plug.

[0105] Among them, when the voltage value of the voltage signal on the microphone pin is less than the first preset threshold, it can be considered that the headphone plug does not include the microphone segment MIC, so that the microphone pin is pulled down to the ground by the inserted headphone plug, and therefore, the headphone plug is identified as a three-stage headphone plug.

[0106] Step 753, continue to determine whether the voltage value of the voltage signal on the microphone pin is less than the second preset threshold. If the voltage value of the voltage signal on the microphone pin is less than the second preset threshold, execute step 754. If the voltage value of the voltage signal on the microphone pin is greater than or equal to the second preset threshold, execute step 752.

[0107] Step 754: Identify the headphone plug as a four-section headphone plug.

[0108] When the voltage value of the voltage signal on the microphone pin is greater than or equal to the first preset threshold and less than the second preset threshold, it can be considered that the headphone plug includes a microphone segment MIC, and therefore the headphone plug is identified as a four-segment headphone plug.

[0109] When the voltage value of the voltage signal on the microphone pin is greater than or equal to the second preset threshold, the headphone plug can be considered to be an abnormal headphone plug, for example, a headphone plug that does not match the headphone socket, and the abnormal headphone plug is identified as a three-stage headphone plug in the headphone identification logic. In this embodiment, after the headphone plug is identified as a three-stage headphone plug, the controller also turns off the headphone bias voltage, and the microphone function cannot be used normally at the headphone end.

[0110] Among them, the first preset threshold is smaller than the second preset threshold, the second preset threshold can be, for example, 0.1V, the second preset threshold can be, for example, 2V, the headphone bias voltage can be, for example, 2.8V, and the present application does not specifically limit the specific values ​​of the first preset threshold, the second preset threshold and the headphone bias voltage.

[0111] Step 76: After the type of the headphone plug is identified, enable the discharge circuit.

[0112] The specific technical details of steps 71 to 76 can be found in the above-mentioned specific introduction to the structure of the mobile device 100, which will not be elaborated here.

[0113] The headphone plug-in noise elimination method provided in the present application, when detecting that a headphone plug is inserted, first disables the discharge circuit of the microphone pin (i.e., turns off the fast discharge function of the microphone pin) and then turns on the headphone bias voltage. This can prevent the microphone pin from being repeatedly powered on and discharged during the insertion and identification process of the headphone plug, thereby avoiding the generation of fluctuating voltage in the left and right channel circuits and causing current noise. By re-enabling the discharge circuit (i.e., turning on the fast discharge function of the microphone pin) after the headphone plug identification process is completed, the microphone pin can be discharged immediately when the headphone plug is unplugged, thereby avoiding the generation of unplugging noise during the unplugging process of the headphone plug.

[0114] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the above preferred implementation modes, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A mobile device, comprising: A headphone socket, wherein a microphone pin is arranged in the headphone socket; an earphone bias voltage circuit, electrically connected to the microphone pin, wherein the microphone pin receives an earphone bias voltage through the earphone bias voltage circuit; A discharge circuit, electrically connected to the microphone pin, the discharge circuit being used to provide a discharge path for the microphone pin in a conducting state; as well as The controller is used to disable the discharge circuit first, turn on the headphone bias voltage, obtain the voltage signal on the microphone pin, identify the type of the headphone plug according to the obtained voltage signal, and enable the discharge circuit after completing the identification of the type of the headphone plug when detecting that an headphone plug is inserted into the headphone socket.

2. The mobile device according to claim 1, wherein: The headphone socket is also provided with a left channel pin, a right channel pin, a ground pin, and a left detection pin; The mobile device further includes a headphone plug-in noise elimination circuit, and the headphone plug-in noise elimination circuit includes: The discharge circuit; A detection module, used to detect the voltage on the left detection pin and the right channel pin, and output a corresponding detection signal; and A logic control module is electrically connected to the detection module and the discharge circuit respectively. The logic control module generates a corresponding logic control signal based on the detection signal output by the detection module to turn on or off the discharge circuit in an enabled state.

3. The mobile device according to claim 2, wherein: The logic control signal includes a first logic signal and a second logic signal, wherein the logic control module is used to generate the first logic signal when the detection module detects that the voltage on the left detection pin or the voltage on the right channel pin is at a high level, and the first logic signal is used to turn on the discharge circuit in an enabled state, so that the microphone pin discharges through the discharge circuit; and The logic control module is also used to generate the second logic signal when the detection module detects that the voltage on the left detection pin and the voltage on the right channel pin are both at a low level. The second logic signal is used to disconnect the discharge circuit in the enabled state, so that the headphone bias voltage circuit can transmit the headphone bias voltage to the microphone pin.

4. The mobile device according to claim 3, wherein: The detection module comprises: a first detection module, configured to detect a voltage on the left detection pin, and output a first detection signal based on a first reference voltage and the voltage on the left detection pin; and A second detection module, used for detecting the voltage on the right channel pin, and outputting a second detection signal based on a second reference voltage and the voltage on the right channel pin; The logic control module is electrically connected to the output ends of the first detection module and the second detection module respectively, and the logic control module generates corresponding logic control signals based on the first detection signal and the second detection signal to turn on or off the discharge circuit in an enabled state.

5. The mobile device according to any one of claims 2 to 4, characterized in that: The controller is electrically connected to the output end of the logic control module, and the controller detects whether an earphone plug is inserted into the earphone socket based on a logic control signal generated by the logic control module.

6. The mobile device according to any one of claims 2 to 4, characterized in that: Also included is an enable switch electrically connected to the controller and the discharge circuit respectively, the controller is used to enable the discharge circuit by turning on the enable switch, and disable the discharge circuit by turning off the enable switch; The enabling switch is electrically connected between the microphone pin and the discharge circuit, or the enabling switch is electrically connected between the output end of the logic control module and the discharge circuit.

7. The mobile device according to any one of claims 2 to 4, characterized in that: The axial depth of the left detection pin in the headphone socket is equal to the axial depth of the left channel pin in the headphone socket, and when the external headphone plug is fully inserted into the headphone socket, the left detection pin contacts and is electrically connected to the left channel segment of the externally inserted headphone plug.

8. The mobile device according to any one of claims 2 to 4, characterized in that: The discharge circuit includes a ground terminal and a control switch connected in series between the ground terminal and the microphone pin, the control switch is used to turn on or off the discharge circuit, the control end of the control switch is electrically connected to the output end of the logic control module, and the logic control module generates a corresponding logic control signal based on the detection signal output by the detection module to turn on or off the control switch.

9. A method for eliminating headphone plug-in noise, applied to a mobile device according to any one of claims 1 to 8, the method for eliminating headphone plug-in noise comprising: Detect whether a headphone plug is inserted into the headphone socket; If it is detected that an earphone plug is inserted into the earphone socket, the discharge circuit of the microphone pin is first disabled, and then the earphone bias voltage is turned on; Acquire a voltage signal on the microphone pin, and identify the type of the headphone plug according to the acquired voltage signal on the microphone pin; After the type of the headphone plug is identified, the discharge circuit is enabled.

10. The method according to claim 9, characterized in that Identifying the type of the headphone plug according to the acquired voltage signal on the microphone pin includes: Determine whether the voltage value of the voltage signal on the microphone pin obtained is less than a first preset threshold; If the voltage value of the voltage signal on the microphone pin is less than the first preset threshold, identifying the headphone plug as a three-section headphone plug; If the voltage value of the voltage signal on the microphone pin is greater than or equal to the first preset threshold, then continue to determine whether the voltage value of the voltage signal on the microphone pin is less than a second preset threshold; If the voltage value of the voltage signal on the microphone pin is less than the second preset threshold, identifying the headphone plug as a four-section headphone plug; If the voltage value of the voltage signal on the microphone pin is greater than or equal to the second preset threshold, the headphone plug is identified as a three-section headphone plug.

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