CN115396786A

CN115396786A - Mobile device and earphone plugging noise elimination method

Info

Publication number: CN115396786A
Application number: CN202211041484.5A
Authority: CN
Inventors: 陈智维; 张宽
Original assignee: Spreadtrum Communications Shanghai Co Ltd
Current assignee: Spreadtrum Communications Shanghai Co Ltd
Priority date: 2022-08-29
Filing date: 2022-08-29
Publication date: 2022-11-25

Abstract

The application provides a mobile device and a method for eliminating earphone plugging noise, wherein the method comprises the following steps: detecting whether an earphone plug is inserted into the earphone socket; if the earphone plug is inserted into the earphone socket, the discharge circuit of the microphone pin is disabled firstly, and then the earphone bias voltage is started; acquiring a voltage signal on a microphone pin, and identifying the type of an earphone plug according to the acquired voltage signal; after the type identification of the headphone plug is completed, the discharge circuit is enabled. When the method detects that the earphone plug is inserted, the microphone pin can be prevented from being repeatedly electrified and discharged in the inserting and identifying processes of the earphone plug by disabling the discharging circuit and then starting the earphone bias voltage, and the current noise caused by the fluctuation voltage generated in the left and right sound channel circuits is avoided; through enable discharge circuit again after accomplishing the headphone plug discernment, can discharge to the microphone pin at once when the headphone plug extracts, avoid extracting the noise in the headphone plug extracts the in-process production.

Description

Mobile device and earphone plugging noise elimination method

Technical Field

The application relates to the technical field of electronics, in particular to a mobile device and an earphone plugging noise elimination method.

Background

With the popularization of smart mobile devices (such as smart phones, tablet computers, and the like) and the development of electronic technologies, functions loaded on mobile devices are increasing, and users playing audio files or video files by using mobile devices also become an essential part in leisure life, so that earphones are increasingly used. Meanwhile, the earphone mode is favored by users because of fine and real tone quality. Many times the user can use earphone playback mode, can enjoy better tone quality on the one hand, and on the other hand can also avoid influencing other people.

With the increasing popularization of audio and video multimedia technology and the higher and higher quality requirements of consumers, stricter requirements are also put forward on earphone audio design. However, during the insertion and extraction of the headphone, noise is often transmitted from the left channel or the right channel of the headphone, which causes auditory discomfort to the user. If the noise amplitude is large, the noise amplitude also influences the hearing of the user, and therefore the user experience is influenced.

Disclosure of Invention

An object of the application is to provide a mobile device and a method for eliminating earphone plugging noise, so as to solve the technical problem that the earphone plug generates noise in the plugging process in the prior art.

In order to solve the above technical problem, a first aspect of the present application provides a mobile device including an earphone socket, an earphone bias voltage circuit, a discharge circuit, and a controller. And a microphone pin is arranged in the earphone socket. The headset bias voltage circuit is electrically connected with the microphone pin, and the microphone pin receives headset bias voltage through the headset bias voltage circuit. The discharge circuit is electrically connected with the microphone pin and is used for providing a discharge path for the microphone pin in a conducting state. The controller is used for disabling the discharging circuit, then starting an earphone bias voltage, then acquiring a voltage signal on the microphone pin, identifying the type of the earphone plug according to the acquired voltage signal, and enabling the discharging circuit after completing the identification of the type of the earphone plug when detecting that the earphone plug is inserted into the earphone socket.

When the mobile device provided by the application detects that an earphone plug is inserted, the microphone pin discharge circuit is disabled (namely, the rapid discharge function of the microphone pin is closed) first, and then the earphone bias voltage is started, so that repeated electrification and discharge of the microphone pin can be prevented in the insertion and identification processes of the earphone plug, and current noise caused by the generation of fluctuating voltage in the left and right sound channel circuits is avoided; the discharge circuit is enabled again (namely, the rapid discharge function of the microphone pin is started) after the identification process of the earphone plug is completed, so that the microphone pin can be discharged immediately when the earphone plug is pulled out, and the pulling-out noise generated in the pulling-out process of the earphone plug is avoided.

In a possible implementation manner of the first aspect, a left channel pin, a right channel pin, a ground pin, and a left detection pin are further disposed in the earphone socket. The mobile equipment further comprises an earphone plug noise elimination circuit, the earphone plug noise elimination circuit comprises a discharge circuit, a detection module and a logic control module, and the detection module is used for detecting the voltage on the left detection pin and the voltage on the right channel pin and outputting corresponding detection signals. The logic control module is electrically connected with the detection module and the discharge circuit respectively, and generates corresponding logic control signals based on detection signals output by the detection module so as to switch on or off the discharge circuit in an enabled state.

In a possible implementation manner of the first aspect, the logic control signal includes a first logic signal and a second logic signal, where the logic control module is configured to generate the first logic signal when the detection module detects that a voltage at the left detection pin or a voltage at the right channel pin is a high level, and the first logic signal is configured to turn on the discharge circuit in an enabled state, so that the microphone pin is discharged through the discharge circuit, that is, the discharge circuit provides a fast discharge path for the microphone pin. It will be appreciated that the voltage on the left detection pin or the voltage on the right channel pin is high, indicating that the headphone plug is not fully inserted into the headphone jack. Because the earphone bias voltage circuit is electrically connected with the microphone pin, the discharge circuit is electrically connected with the microphone pin to ground, and meanwhile, the earphone bias voltage circuit is also electrically connected with the ground through the discharge circuit, namely, the discharge circuit provides a ground loop for the earphone bias voltage circuit, so that the aim of preventing the earphone bias voltage circuit from transmitting earphone bias voltage to the microphone pin can be fulfilled.

The logic control module is further configured to generate the second logic signal when the detection module detects that the voltage at the left detection pin and the voltage at the right channel pin are both low levels, where the second logic signal is used to disconnect the discharge circuit in an enable state, so that the earphone bias voltage circuit can transmit an earphone bias voltage to the microphone pin, that is, the earphone bias voltage circuit is enabled. It will be appreciated that the voltage on the left detection pin and the voltage on the right channel pin are both low, indicating that a headphone plug may have been fully inserted into the headphone jack.

In a possible implementation manner of the first aspect, the detection module includes a first detection module and a second detection module, and the first detection module is 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. The second detection module is 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 with the output ends of the first detection module and the second detection module respectively, and generates corresponding logic control signals based on the first detection signal and the second detection signal to switch on or off the discharge circuit in an enabled state.

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.

In a possible implementation manner of the first aspect, the apparatus further includes an enable switch 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;

the enabling switch is electrically connected between the microphone pin and the discharging circuit, so that the discharging circuit can be electrically connected with the microphone pin by turning on the enabling switch, and the aim of enabling the discharging circuit is fulfilled; the discharge circuit can be electrically disconnected from the microphone pin by disconnecting the enable switch, so that the discharge circuit is forbidden.

Optionally, the enable switch is electrically connected between the output end of the logic control module and the discharge circuit. Therefore, the discharge circuit can be electrically connected with the output end of the logic control module by turning on the enabling switch, so that the discharge circuit can be turned on or off by the logic control signal output by the logic control module, and the purpose of enabling the discharge circuit is achieved; the discharge circuit can be electrically disconnected with the output end of the logic control module by disconnecting the enable switch, so that the logic control signal output by the logic control module cannot control the on-off state of the discharge circuit, and the purpose of forbidding the discharge circuit is achieved.

In a possible implementation manner of the first aspect, the axial depth of the left detection pin in the earphone socket is approximately equal to the axial depth of the left channel pin in the earphone socket, and the left detection pin is in contact with and electrically connected to the left channel section of the externally inserted earphone plug when the external earphone plug is fully inserted into the earphone socket. In this way, it is ensured that the voltage on the left detection pin may change when the headphone plug is inserted into the headphone socket and the left channel pin is in contact with the headphone plug.

In a possible implementation manner 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 configured to turn on or off the discharge circuit, a control terminal of the control switch is electrically connected to an output terminal of the logic control module, and the logic control module generates a corresponding logic control signal based on a detection signal output by the detection module to turn on or off the control switch.

A second aspect of the present application provides a method for eliminating a plugging noise of a headset, which is applied to the mobile device of the first aspect, and the method for eliminating the plugging noise of the headset includes: detecting whether an earphone plug is inserted into the earphone socket; if the earphone plug is detected to be inserted into the earphone socket, disabling a discharge circuit of a microphone pin, and then starting an earphone bias voltage; acquiring a voltage signal on the microphone pin, and identifying the type of the earphone plug according to the acquired voltage signal on the microphone pin; enabling the discharge circuit after completing the type recognition of the earphone plug.

According to the earphone plugging noise elimination method, when the earphone plug is detected to be plugged, the discharge circuit of the microphone pin is disabled (namely, the quick discharge function of the microphone pin is closed), and then the earphone bias voltage is started, so that the microphone pin can be prevented from being repeatedly electrified and discharged in the plugging and identification processes of the earphone plug, and current noise caused by the generation of fluctuating voltage in the left and right sound channel circuits is avoided; the discharge circuit is enabled again (namely, the quick discharge function of the microphone pin is started) after the identification process of the earphone plug is completed, so that the microphone pin can be discharged immediately when the earphone plug is pulled out, and the pulling-out noise generated in the pulling-out process of the earphone plug is avoided.

In a possible implementation manner of the second aspect, identifying the type of the headset plug according to the acquired voltage signal on the microphone pin includes: judging whether the voltage value of the acquired voltage signal on the microphone pin is smaller than the first preset threshold value or not; if the voltage value of the voltage signal on the microphone pin is smaller than the first preset threshold value, identifying the earphone plug as a three-section type earphone plug; if the voltage value of the voltage signal on the microphone pin is greater than or equal to the first preset threshold, continuously judging 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 smaller than the second preset threshold value, identifying the earphone plug as a four-section type earphone plug; and if the voltage value of the voltage signal on the microphone pin is greater than or equal to the second preset threshold value, identifying the earphone plug as a three-section type earphone plug.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a conventional mobile device including a headset jack for inserting an external headset plug.

Fig. 2 is a flowchart of a conventional earphone plug identification method.

Fig. 3 is a schematic structural diagram of a mobile device according to a first embodiment of the present application, where the mobile device includes an earphone socket for inserting an external earphone plug, and an earphone plug in the earphone socket is in a first insertion state.

Fig. 4 is a schematic structural diagram of a mobile device according to a second embodiment of the present application.

Fig. 5 is a schematic view of the headset plug of fig. 3 in a second plugged-in state, wherein the mobile device is in a standby mode.

Fig. 6 is a schematic diagram of the earphone plug shown in fig. 3 in a second insertion state, wherein the mobile device is in an audio playing mode.

Fig. 7 is a flowchart of a method for eliminating noise generated by plugging and unplugging an earphone according to an embodiment of the present application.

Fig. 8 is a detailed flowchart of step 75 in the flowchart shown in fig. 7.

Description of the main elements

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. The drawings are for illustrative purposes only and are presented for purposes of illustration only and should not be construed as limiting the present application. It is to be understood that the embodiments described are only a few examples of the present application and are not intended to be exhaustive or all examples. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Earphones (ears, headphones, head-sets, earfaces) are a pair of conversion units that receive electrical signals from a media player (e.g., a smart phone, a tablet, a walkman, etc. mobile device) and convert them into audible sound waves using a speaker near the ear. The earphone can be separated from the media player, the connection between the earphone and the media player can be realized by only using one plug, and the earphone can independently listen to music without influencing other people; can also isolate the sound of the surrounding environment, and is very helpful for users who use the media player in a noisy environment such as a recording studio, a bar, a journey, sports, and the like.

For wired headsets, the mobile device typically needs to identify the headset plug to enable proper data transmission when the headset plug is plugged into a headset jack on the mobile device. Specifically, taking a four-segment headphone plug and a corresponding conventional headphone jack as an example, as shown in fig. 1, the headphone plug 200 includes a left channel segment L, a right channel segment R, a ground segment GND, and a microphone segment MIC, which are separated from each other by an insulating ring (e.g., black blocks shown in fig. 1). Inside the earphone, 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 resistor R21 and the resistor R22 are equivalent resistors of the internal load of the earphone, and have small impedance values. Accordingly, 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. Wherein, 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 as follows: when the external earphone plug 200, which is mated with the earphone jack 10, is completely inserted into the earphone jack 10, the left channel section L, the right channel section R, the ground section GND and the microphone section MIC of the externally inserted earphone plug 200 are in one-to-one contact and electrically connected.

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 may be a resistor device with a small resistance value. The microphone pin 4 is electrically connected to the earphone bias voltage circuit 40 and the discharging circuit 301, respectively, wherein the microphone pin 4 receives an earphone bias voltage Head _ Micbias through the earphone bias voltage circuit 40, so that the controller 20 can correctly identify the type of the earphone plug 200, for example, identify whether the earphone plug 200 is a three-segment type or a four-segment type, after the earphone plug 200 of an external earphone is inserted into the earphone socket 10. Wherein, the headset bias voltage Head _ Micbias can be provided by the controller 20 and transmitted to the microphone pin 4 through the headset bias voltage circuit 40. The headset 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 configured to provide a discharge path to the microphone pin 4 in an on state. It is understood that the earphone bias voltage Head _ Micbias transmitted to the microphone pin 4 by the earphone bias voltage circuit 40 will raise the voltage on the microphone pin 4; and the microphone pin 4 is discharged through the discharge circuit 301, the voltage on the microphone pin 4 can be reduced.

In order to realize the plugging and unplugging identification of the earphone plug 200, a left detection pin 5 is further arranged in the earphone socket 10, wherein the axial depth of the left detection pin 5 in the earphone socket 10 is substantially equal to the axial depth of the left channel pin 1 in the earphone socket 10, and the left detection pin 5 is in contact with and electrically connected with the left channel section L of the externally inserted earphone plug 200 when the external earphone plug 200 is completely inserted into the earphone socket 10. In this way, it is ensured that when the earphone plug 200 is inserted into the earphone jack 10 and the left channel pin 1 contacts the earphone plug 200, the voltage on the left detection pin 5 may change. It should be noted that "substantially equal" defined in the present application means approximately equal, is not limited to absolute equal, and includes a relationship that is not absolute equal due to factors such as design tolerance and structural flatness.

It should be understood that the "pin" mentioned in the present application may be embodied as a metal contact, a metal spring, and the like in terms of physical structure, and the physical structure of the pin is not particularly limited in the present application. The "axial depth" of the pin in the earphone socket referred to in this application refers to the axial distance from the open end of the earphone socket to the location where the pin is disposed.

Fig. 2 is a flowchart of a conventional headset plug identification method. The identification method can be applied to the mobile device 100', and comprises the following steps:

step 21, detecting whether an earphone plug is inserted into the earphone socket. If it is detected that the earphone plug is inserted into the earphone jack, step 22 is executed. Otherwise, returning to step 21, continuously detecting whether an earphone plug is inserted into the earphone socket.

Specifically, in one embodiment, 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 can be determined 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 earphone plug 200 is inserted into the earphone socket 10.

In another embodiment, as shown in fig. 1, when the earphone plug 200 is inserted into the earphone socket 10, and the left channel segment L of the earphone plug 200 short-circuits the left detection pin 5 and the left channel pin 1, and the right channel segment R of the earphone plug 200 short-circuits the right channel pin 2, it can be determined whether there is an earphone plug 200 inserted into the earphone socket 10 by detecting voltages on the left detection pin 5 and the right channel pin 2 of the earphone socket 10. When the voltages on the left detection pin 5 and the right channel pin 2 are both low levels, it can be determined that the earphone plug 200 is inserted into the earphone socket 10.

Step 22, the headset bias voltage is turned on.

Step 23, acquiring a voltage signal on a microphone pin of the earphone socket 10.

And 24, judging whether the voltage value of the acquired voltage signal on the microphone pin is smaller than a preset threshold value. If the voltage value of the voltage signal at the microphone pin is smaller than the preset threshold, step 25 is executed. Otherwise, step 26 is performed.

The preset threshold value can be set to 0.1V, and the specific value of the preset threshold value is not specifically limited in the application.

And 25, identifying the earphone plug as a three-section earphone plug.

And step 26, identifying the earphone plug as a four-section earphone plug.

Wherein, in the identification method, the headset bias voltage Head _ Micbias may be turned on by a controller of the mobile device and the type of the headset plug 200 may be identified according to a voltage value on the microphone pin 4 of the headset jack 10.

However, although the insertion of the earphone plug 200 can be recognized by using the structure of the earphone jack 10 shown in fig. 1 and the recognition method shown in fig. 2, it cannot be accurately recognized whether the earphone plug 200 is completely inserted into the earphone jack 10. And the identification method shown in fig. 2 is to turn on the headphone bias voltage Head _ Micbias upon identifying the insertion of the headphone plug 200, so that noise is often transmitted from the left channel or the right channel of the headphone during the insertion of the headphone plug 200 into the headphone jack 10 or during the extraction of the headphone plug 200 from the headphone jack 10, and particularly, continuous current noise is generated due to repeated power-on and rapid discharge of the microphone pin 4 during the slow insertion of the headphone plug 200, which causes auditory discomfort to the user. If the noise amplitude is large, the noise amplitude also influences the hearing of the user, and therefore the user experience is influenced.

Specifically, for example, as shown in fig. 1, when the earphone plug 200 is not fully inserted into the position, but the left channel segment L of the earphone plug 200 short-circuits the left channel pin 1 and the left detection pin 5 of the earphone socket 10, and the right channel segment R of the earphone plug 200 short-circuits the right channel pin 2, the controller 20 of the mobile device 100' detects that the voltages at the left detection pin 5 and the right channel pin 2 are both low level signals, and therefore determines that the earphone plug 200 is inserted, and at this time, the controller 20 turns on the earphone bias voltage Head _ Micbias, thereby increasing the voltage at the microphone pin 4 of the earphone socket 10. Because the microphone pin 4 of the earphone socket 10 contacts the microphone segment MIC of the earphone plug 200, and the grounding pin 3 of the earphone socket 10 contacts the insulating ring of the earphone plug 200 to be disconnected, the earphone bias voltage Head _ Micbias applied to the microphone pin 4 respectively enters the left and right channel circuits through the microphone segment MIC of the earphone plug 200, the earphone internal circuit, and the left channel segment L and the right channel segment R of the earphone plug 200, so that the voltages on the left detection pin 5 and the right channel pin 2 of the earphone socket 10 rise above a preset threshold value, thereby triggering the rapid discharge of the microphone pin 4; and the rapid discharge of the microphone pin 4 can make the voltage on the left detection pin 5 and the right channel pin 2 of the earphone socket 10 fall below the preset threshold value again, so as to trigger the rapid discharge of the microphone pin 4 to be turned off, and the microphone pin 4 can be powered on again after the rapid discharge of the microphone pin 4 is turned off, and the earphone bias voltage Head _ Micbias respectively enters the left channel circuit and the right channel circuit again, so that the voltage on the left detection pin 5 and the right channel pin 2 of the earphone socket 10 rises above the preset threshold value again, so as to trigger the rapid discharge of the microphone pin 4 again. The repeated power-on and power-off of the microphone pin 4 can cause fluctuating voltage to appear in the left and right sound channel circuits, so that current noise is generated, and particularly, the continuous current noise is more obvious when the earphone end is heard in the slow plugging process of the earphone plug. The reason why the pull-out noise is generated is that when the earphone plug enters the pull-out timing sequence, the controller 20 does not immediately cut off the earphone bias voltage Head _ Micbias, which causes the earphone bias voltage Head _ Micbias to be connected to the left and right channel circuits to generate current noise. The higher the headset bias voltage Head _ Micbias is, the higher the noise generated in the plugging and unplugging process of the headset plug is.

In order to solve the technical problem of noise generated by the earphone plug during the plugging and unplugging process in the prior art, as shown in fig. 3, the present application provides a mobile device 100 capable of eliminating the noise generated by plugging and unplugging the earphone plug. The mobile device 100 includes, but is not limited to, an electronic product such as a smart phone, a tablet computer, a walkman, an automobile, and the like.

In this embodiment, the mobile device 100 includes an earphone jack 10, a controller 20, an earphone plug noise cancellation circuit 30, and an earphone bias voltage circuit 40, where the earphone jack 10 and the earphone bias voltage circuit 40 shown in fig. 3 are respectively the same as the earphone jack 10 and the earphone bias voltage circuit 40 shown in fig. 1.

The earphone plugging noise canceling circuit 30 includes the discharging circuit 301, in this embodiment, the controller 20 is configured to disable the discharging circuit 301, then turn on an earphone bias voltage Head _ Micbias, then acquire a voltage signal at the microphone pin 4, identify a type of the earphone plug 200 according to the acquired voltage signal, and enable the discharging circuit 301 after completing the type identification of the earphone plug 200 when detecting that the earphone plug 200 is inserted into the earphone socket 10.

When the mobile device 100 provided by the application detects that the headphone plug 200 is inserted, the microphone pin 4 discharge circuit 301 is disabled (i.e., the fast discharge function of the microphone pin 4 is turned off), and then the headphone bias voltage Head _ Micbias is turned on, so that the microphone pin 4 can be prevented from being repeatedly powered on and discharged in the insertion and identification processes of the headphone plug 200, and current noise caused by the generation of fluctuating voltage in the left and right channel circuits is avoided; by re-enabling the discharging circuit 301 (i.e., turning on the fast discharging function of the microphone pin 4) after the identification process of the headphone plug 200 is completed, the microphone pin 4 can be immediately discharged when the headphone plug 200 is pulled out, thereby preventing the pulling-out noise generated in the pulling-out process of the headphone plug 200.

Specifically, the earphone plugging noise elimination circuit 30 further includes a detection module 302 and a logic control module 303. The detection module 302 is configured to detect voltages on the left detection pin 5 and the right channel pin 2, and output corresponding detection signals. The logic control module 303 is electrically connected to the detection module 302 and the discharge circuit 301, 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 an enabled state.

In this embodiment, the discharge circuit 301 includes a ground GND and a control switch Q3 connected in series between the ground 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 to turn on or off the control switch Q3 based on the detection signal output by the detection module 302, so as to turn on or off the discharge circuit 301 in an enabled state. That is, the discharge circuit 301 and the logic control module 303 together constitute an enable control circuit of the earphone bias voltage circuit 40. In this embodiment, the control switch Q3 is in a normally open state.

In this embodiment, the logic control signal includes a first logic signal and a second logic signal, the logic control module 303 is configured 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, and the first logic signal is configured to turn on the control switch Q3, so as to turn on the discharge circuit 301 in an enabled state, so that the microphone pin 4 is discharged through the discharge circuit 301, that is, the discharge circuit 301 provides a fast discharge path for the microphone pin 4. It is understood that the voltage on the left detection pin 5 or the voltage on the right channel pin 2 is high, indicating that the headphone plug 200 is not fully inserted into the headphone jack 10. Since the headphone bias voltage circuit 40 is electrically connected to the microphone pin 4, while the discharging circuit 301 connects the microphone pin 4 to ground, the headphone bias voltage circuit 40 is also electrically connected to ground through the discharging circuit 301, that is, the discharging circuit 301 provides a ground loop for the headphone bias voltage circuit 40, so as to achieve the purpose of preventing the headphone bias voltage circuit 40 from transmitting headphone bias voltage Head _ Micbias to the microphone pin 4.

The logic control module 303 is further configured 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, where the second logic signal is used to disconnect the control switch Q3, so as to disconnect the discharge circuit 301 in an enabled state, so that the headset bias voltage circuit 40 can transmit a headset bias voltage Head _ Micbias to the microphone pin 4, that is, the headset bias voltage circuit 40 is enabled. It will be appreciated that the voltage on the left detection pin 5 and the voltage on the right channel pin 2 are both low, indicating that the headphone plug 200 may have been fully inserted into the headphone jack 10.

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 plugging/unplugging state of the external headset plug 200 and controls the on/off of the headset 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 recognizing that a headphone plug is inserted into the headphone jack 10 based on the logic control signal generated by the logic control module 303, and turns off the headphone bias voltage Head _ Micbias in time when recognizing that the headphone plug 200 is unplugged based on the logic control signal.

To enable enabling and disabling the discharge circuit 301, the mobile device 100 further includes an enable switch Q4 electrically connected to the controller 20 and the discharge circuit 301, respectively, the controller 20 being configured to enable the discharge circuit 301 by turning on the enable switch Q4 and disable the discharge circuit 301 by turning off the enable switch Q4.

In one embodiment, as shown in fig. 3, the enable switch Q4 may be electrically connected between the microphone pin 4 and the discharge circuit 301. Specifically, the control end of the enable switch Q4 is electrically connected to the controller 20, so as to realize on-off control of the enable switch Q4 by the controller 20. In this way, the discharge circuit 301 and the microphone pin 4 can be electrically connected by turning on the enable switch Q4, so as to achieve the purpose of enabling the discharge circuit 301; the discharge circuit 301 can be electrically disconnected from the microphone pin 4 by turning off the enable switch Q4, so as to disable the discharge circuit 301. The enable switch Q4 may be a transistor, such as a MOS transistor, and the type of the enable switch Q4 is not particularly limited in this application.

Alternatively, in another embodiment, as shown in fig. 4, the enable switch Q4 may be electrically connected between the output end of the logic control module 303 and the discharge circuit 301. Specifically, the control end of the enable switch Q4 is electrically connected to the controller 20, so as to implement on-off control of the enable switch Q4 by the controller 20. The enable switch Q4 may be electrically connected between the output terminal of the logic control module 303 and the control terminal of the control switch Q3. In this way, the discharge circuit 301 and the output end of the logic control module 303 can be kept electrically connected by turning on the enable switch Q4, so that the discharge circuit 301 can be turned on or off by the logic control signal output by the logic control module 303, thereby achieving the purpose of enabling the discharge circuit 301; the discharge circuit 301 can be electrically disconnected from the output end of the logic control module 303 by disconnecting the enable switch Q4, 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.

Referring to fig. 3 again, in the present embodiment, the detecting module 302 includes a first detecting module 31 and a second detecting module 32, wherein the first detecting module 31 is configured to detect a voltage on the left detecting pin 5 and output a first detecting signal based on a first reference voltage and the voltage on the left detecting pin 5. The second detecting module 32 is configured to detect a voltage on the right channel pin 2, and output a second detecting signal based on a 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 jack 10 into a right detection pin.

The logic control module 303 is electrically connected to output terminals of the first detection module 31 and the second detection module 32, and the logic control module 303 generates a corresponding logic control signal to turn on or off the discharge circuit 301 in an enabled state based on the first detection signal and the second detection signal.

The specific structures of the first detecting module 31, the second detecting module 32 and the logic control module 303 are described below.

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

Since the left channel segment L of the earphone plug 200 is short-circuited to the left channel pin 1 and the left detection pin 5 of the earphone socket 10 when the earphone plug 200 is fully inserted into the earphone socket 10, the voltages at 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, i.e., a standby mode and an audio play mode, the voltages at the left channel pin 1 and the right channel pin 2 are different, wherein the voltages at the standby mode and the right channel pin 1 and the right channel pin 2 are much lower than the voltages at the audio play mode. Therefore, the controller 20 may misinterpret the state of the earphone plug 200 in the audio play mode as the unplugged state.

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

The first switch S1 is used to conduct the electrical connection between one of the output terminal of the first comparator Comp1 and the output terminal of the second comparator Comp2 and the input terminal of the enable control module 34. Specifically, when the mobile device 100 is not in the audio play mode or the headset plug 200 is not completely inserted into the headset socket 10, the first switch S1 turns on the electrical connection between the output terminal of the first comparator Comp1 and the input terminal of the enable control module 34. When the mobile device 100 is in the audio playing mode and the earphone plug 200 is fully inserted into the earphone socket 10, the first switch S1 switches on the electrical connection between the output terminal of the second comparator Comp2 and the input terminal of the enable control module 34.

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 smaller than the voltage value of the second reference voltage Vref2. The output voltage value of the first pull-up power supply VDD1 is greater than the voltage value of the first reference voltage Vref1 and the voltage value of the second reference voltage Vref2, respectively. When the mobile device 100 is not in the audio playing mode or the earphone plug 200 is not completely inserted into the earphone 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 smaller than the voltage value of the first reference voltage Vref 1; when the mobile device 100 is in the audio playing mode and the earphone plug 200 is fully inserted into the earphone socket 10, the audio signal in the left channel circuit may make the voltage value on the left channel pin 1 greater than the voltage value of the first reference voltage Vref1 and less than the voltage value of the second reference voltage Vref2.

The second detection module 32 has a structure 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 a second pull-up power supply VDD2, and a second connection node P2 is formed on a connection circuit between the second pull-up resistor R32 and the right channel pin 2. The second comparing unit 321 includes an input terminal electrically connected to the second connection node P2 and the input terminal of the second reference voltage, respectively, and an output terminal electrically connected to the input terminal of the enable control module 34. In this embodiment, the voltage at the second connection node P2 is substantially equal to the voltage at the right channel pin 2. The second comparing unit 321 outputs the second detection signal to the input terminal of the enable control module 34 based on the second reference voltage and the voltage on the right channel pin 2.

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

The second switch S2 is used to conduct the electrical connection between one of the output terminal of the third comparator Comp3 and the output terminal of the fourth comparator Comp4 and the input terminal of the enable control module 34. Specifically, when the mobile device 100 is not in the audio playing mode or the earphone plug 200 is not completely inserted into the earphone socket 10, the second switch S2 turns on the electrical connection between the output terminal of the third comparator Comp3 and the input terminal of the enable control module 34. When the mobile device 100 is in the audio playing mode and the earphone plug 200 is fully inserted into the earphone socket 10, the second switch S2 turns on the electrical connection between the output terminal of the fourth comparator Comp4 and the input terminal of the enable control module 34. It is understood that the conductive states of the first switch S1 and the second switch S2 can be controlled by the control signal output by the controller 20, and the present application is not limited thereto.

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 smaller than the voltage value of the fourth reference voltage Vref4. The output voltage value of the second pull-up power supply VDD2 is greater than the voltage value of the third reference voltage Vref3 and the voltage value of the fourth reference voltage Vref4, respectively. In a state where the earphone plug 200 is completely inserted into the earphone jack 10, if the mobile device 100 is not in the audio playing mode, since the right channel pin 2 is grounded through the right channel segment R, the earphone internal circuit, the ground GND and the ground pin 3, or through internal pull-down resistors in the right channel segment R, the earphone internal circuit, the left channel segment L, the left channel pin 1 and the left channel circuit, the voltage value at the right channel pin 2 is smaller than the voltage value of the third reference voltage Vref 3; when the mobile device 100 is in the audio playing mode and the headphone plug 200 is fully inserted into the headphone socket 10, the audio signal in the right channel circuit causes the voltage value on the right channel pin 2 to be greater than the voltage value of the third reference voltage Vref3 and less than the voltage value of the fourth reference voltage Vref4.

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

It should be noted that the above parameters are only exemplary parameters of an implementation mode for implementing the identification function of the plug-in and plug-out state of the headset, but values of the pull-up resistors, the pull-up power supply and the reference voltage are not limited to the above parameters, and a person skilled in the art can adaptively adjust or modify values of the pull-up resistors, the pull-up power supply and the reference voltage of each detection module and a connection mode of the input end of each comparator according to actual design requirements to implement identification of the plug-in and plug-out state of the headset. For example, in another embodiment, the first pull-up resistor R31 and the second pull-up resistor R32 may have different resistance values. Alternatively, the output voltage values of the first pull-up power source VDD1 and the second pull-up power source VDD2 may be set to different voltage values. Alternatively, the first reference voltage Vref1 and the third reference voltage Vref3 may also take different voltage values. Alternatively, the second reference voltage Vref2 and the fourth reference voltage Vref4 may also adopt different voltage values. All technical modifications made according to the technical scheme of the application are covered in the protection scope of the application.

The logic control module 303 includes an input terminal electrically connected to the output terminals of the first detection module 31 and the second detection module 32, respectively. In this embodiment, the logic control module 303 employs a nand gate G1, where the nand gate G1 is configured to perform and operation, then perform non-operation, and finally output a corresponding logic control signal on the detection signals output by the first detection module 31 and the second detection module 32.

The control switch Q3 is a transistor with a high level conduction, such as an NMOS transistor. It can be understood that, the earphone plugging noise elimination circuit 30 realizes the function of fast discharging the microphone pin 4 by connecting the NMOS transistor in series to the discharge circuit 301, and can quickly respond to the plugging state of the earphone plug 200 by using the characteristic of fast on and off speed of the transistor, so as to eliminate the earphone plugging noise more thoroughly.

It should be noted that, in this embodiment, the logic control module 303 employs the nand gate G1, and the control switch Q3 employs the NMOS transistor that is turned on at a high level to exemplify an implementation of implementing the control function of the headphone bias voltage Head _ Micbias, but the logic control module 303 is not limited to employing the nand gate, and the control switch Q3 is not limited to employing the NMOS transistor that is turned on at a high level, and a person skilled in the art may employ one or more logic control modules 303 of other types to output corresponding logic control signals based on the detection signals output by the two detection modules and employ other types of switching transistors to control on/off of the discharge circuit 301 according to actual design requirements, thereby implementing the control function of the headphone bias voltage Head _ Micbias. All technical modifications made according to the technical solutions of the present application are covered in the protection scope of the present application.

In one embodiment, the headset plug noise cancellation circuit 30 may be packaged in the form of a chip.

The operation principle of the mobile device 100 for eliminating the noise generated by plugging and unplugging the earphone will be described with reference to the circuit configurations shown in fig. 3 and 5 as an example. The truth tables of the detection pins, the comparators, the nand gate, the earphone bias voltage and the NMOS transistor are respectively shown in the following table 1:

TABLE 1

When the headphone plug 200 is in the position shown in fig. 3 during the insertion of the external headphone plug 200 into the headphone jack 10, the first switch S1 keeps conducting the electrical connection between the output terminal of the first comparator Comp1 and the input terminal of the logic control module 303, and the second switch S2 keeps conducting the electrical connection between the output terminal of the third comparator Comp3 and the input terminal of the logic control module 303. The left channel segment L of the headphone plug 200 shorts the left channel pin 1 of the headphone jack 10 with the left detection pin 5, and the right channel segment R of the headphone plug 200 shorts the right channel pin 2 of the headphone jack 10, so that the left detection pin 5 is grounded through an internal pull-down resistor (not shown) of the left channel pin 1, and the right channel pin 2 is grounded through the internal pull-down resistor of the right channel segment R, the headphone internal circuit, the left channel segment L, and the left channel pin 1. Accordingly, the first comparator Comp1 and the third comparator Comp3 each output a high level signal. The nand gate G1 outputs a low level signal, i.e., the second logic signal, based on the high level signals output from the first comparator Comp1 and the third comparator Comp 3. The controller 20 recognizes that the earphone plug 200 is inserted into the earphone socket 10 according to the second logic signal, as described above, the controller 20 turns off the enable switch Q4 to disable the discharging circuit 301, and then turns on the earphone bias voltage Head _ Micbias to power on the microphone pin 4.

In the position shown in fig. 3, since the microphone pin 4 of the earphone jack 10 contacts the microphone segment MIC of the earphone plug 200 and the ground pin 3 of the earphone jack 10 contacts the insulating ring of the earphone plug 200 to be disconnected, the earphone bias voltage Head _ Micbias loaded on the microphone pin 4 enters the left and right channel circuits through the microphone segment MIC of the earphone plug 200, the earphone internal circuit, and the left channel segment L and the right channel segment R of the earphone plug 200, respectively, so that the voltages on the left detection pin 5 and the right channel pin 2 of the earphone jack 10 rise above the preset threshold, 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 from the first comparator Comp1 and the third comparator Comp 3. At this time, although the nand gate G1 outputs the first logic signal, the discharge circuit 301 is disabled, and therefore, the first logic signal cannot be used to turn on the discharge circuit 301, so that the fast discharge of the microphone pin 4 is not triggered. Meanwhile, 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 jack 10, so that the microphone pin 4 is kept powered on, the voltages on the left detection pin 5 and the right channel pin 2 of the headphone jack 10 are kept in a stable voltage state although rising above a preset threshold, and no current noise is generated. Therefore, the purpose of eliminating the insertion noise of the earphone plug can be achieved.

When the earphone plug 200 is continuously inserted into the earphone jack 10 and located at the position shown in fig. 5, that is, the earphone plug 200 is fully inserted into the earphone jack 10, the first switch S1 keeps conducting the electrical connection between the output terminal of the first comparator Comp1 and the input terminal of the logic control module 303, and the second switch S2 keeps conducting the electrical connection between the output terminal of the third comparator Comp3 and the input terminal of the logic control module 303. The microphone pin 4 of the earphone socket 10 contacts the microphone segment MIC of the earphone plug 200, and the ground pin 3 of the earphone socket 10 is electrically connected to the ground terminal GND of the earphone plug 200, so that the earphone 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 earphone plug 200, the earphone internal circuit, and the ground terminal GND of the earphone plug 200, that is, the earphone bias voltage Head _ Micbias loaded on the microphone pin 4 does not enter the left and right channel circuits.

Meanwhile, in the position shown in fig. 5, the left channel section L of the headphone plug 200 shorts the left channel pin 1 of the headphone jack 10 with the left detection pin 5, and the right channel section R of the headphone plug 200 shorts the right channel pin 2 of the headphone jack 10, so that the voltages of the left detection pin 5 and the right channel pin 2 are both pulled low, and accordingly, both the first comparator Comp1 and the third comparator Comp3 output a high level signal. The nand gate G1 outputs a low level signal, i.e., the second logic signal, based on the high level signals output from the first comparator Comp1 and the third comparator Comp 3. As described above, after the type identification of the headset plug 200 is completed, the controller 20 enables the discharging circuit 301 by turning on the enabling switch Q4, and at this time, the second logic signal can be used to turn off the controlling switch Q3, thereby turning off the discharging circuit 301, so that the headset bias voltage circuit 40 can continuously transmit the headset bias voltage Head _ Micbias to the microphone pin 4.

When the earphone plug 200 is in the fully inserted state and stays in the earphone jack 10, if the mobile device 100 is in the standby mode, as shown in fig. 5, the first switch S1 continues to conduct the electrical connection between the output terminal of the first comparator Comp1 and the input terminal of the logic control module 303, and the second switch S2 continues to conduct the electrical connection between the output terminal of the third comparator Comp3 and the input terminal of the logic control module 303. If the mobile device 100 is in the audio playing mode, as shown in fig. 6, the first switch S1 switches on the electrical connection between the output terminal of the second comparator Comp2 and the input terminal of the logic control module 303, and the second switch S2 switches on the electrical connection between the output terminal of the fourth comparator Comp4 and the input terminal of the logic control module 303. In this way, in the process of pulling out the headphone plug 200, the headphone plug noise canceling circuit 30 can correctly recognize the pulling out operation of the headphone plug 200 even when different voltages are applied to the left and right sound channel pins in different usage modes of the mobile device 100.

When the headphone plug 200 is pulled out from the fully inserted state (e.g. the position shown in fig. 6) and located at the position shown in fig. 3, since the microphone pin 4 is also loaded with the headphone bias voltage Head _ Micbias, as described above, the headphone bias voltage Head _ Micbias enters the left and right channel circuits through the microphone segment MIC of the headphone plug 200, the headphone internal circuit, and the left channel segment L and the right channel segment R of the headphone plug 200, respectively, so that the voltages on the left detection pin 5 and the right channel pin 2 of the headphone jack 10 rise above the preset threshold, 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 from the first and third comparators Comp1 and Comp3, so that the control switch Q3 is immediately turned on, thereby electrically connecting the microphone pin 4 to ground for rapid discharge. Meanwhile, the controller 20 recognizes that the earphone plug 200 is unplugged according to the first logic signal, and thus the controller 20 turns off the earphone bias voltage Head _ Micbias. Therefore, the purpose of eliminating the pulling-out noise of the earphone plug can be achieved.

It is understood that, if the mobile device 100 is in the audio playing mode before the headphone plug 200 is unplugged, when the controller 20 recognizes that the headphone plug 200 is unplugged, the controller 20 further controls the first switch S1 to conduct the electrical connection between the output terminal of the first comparator Comp1 and the input terminal of the logic control module 303, and controls the second switch S2 to conduct the electrical connection between the output terminal of the third comparator Comp3 and the input terminal of the logic control module 303.

When the earphone plug 200 is pulled out from the fully inserted state, because the microphone pin 4 has residual charges, the earphone plug noise canceling circuit 30 of the present application electrically connects the microphone pin 4 to the ground by providing the discharging circuit 301, and can quickly respond to the pulling out operation of the earphone plug 200 from the hardware to quickly discharge the microphone pin 4, thereby completely canceling the pulling out noise of the earphone plug 200.

Further, in the process of pulling out the external earphone plug 200 from the fully plugged-in state, since the controller 20 first needs to acquire a relevant detection signal, for example, a logic control signal output by the logic control module 303 to perform plug-in and pull-out recognition, the earphone bias voltage Head _ Micbias cannot be immediately turned off in response to the pulling-out operation of the earphone plug 200, and in addition, the earphone bias voltage Head _ Micbias cannot be immediately turned off in response to the pulling-out operation even when the controller 20 fails, thereby causing the pulling-out noise. In view of this problem, the earphone plug noise canceling circuit 30 of the present application, by providing the discharging circuit 301 including the switching tube, can rapidly respond to the plugging operation of the earphone plug 200 from hardware to rapidly discharge the microphone pin 4, so that the noise caused by the slow response speed of software control of the controller 20 and the inability to immediately respond to the plugging operation can be effectively avoided, that is, the plugging noise caused by the too late cutting off of the earphone bias voltage Head _ Micbias when the earphone plug 200 is plugged out is effectively avoided.

It should be noted that the embodiments shown in fig. 3-6 of the present application take a four-segment american standard plug structure and a corresponding earphone jack 10 structure as examples, and a related structure included in the mobile device 100 provided by the present application for eliminating earphone plugging noise is described. It can be understood by those skilled in the art that the related structure for eliminating the plugging noise of the earphone of the present application is also applicable to a four-segment european standard plug structure and a corresponding earphone socket structure, and in practical applications, those skilled in the art only need to adjust the arrangement positions of the ground pin 3 and the microphone pin 4 in the earphone socket according to the positions of the ground segment GND and the microphone segment MIC of the earphone plug 200.

Referring to fig. 7, the present application further provides a method for eliminating earphone plugging noise, wherein the method can be applied to the mobile device 100. As shown in fig. 7, the method comprises the steps of:

step 71, detecting whether an earphone plug is inserted into the earphone socket. If it is detected that the earphone plug is inserted into the earphone jack, step 72 is executed. Otherwise, returning to step 71, continuing to detect whether an earphone plug is inserted into the earphone socket.

Step 72, disable the discharge circuit of the microphone pin.

Step 73, the headset bias voltage is turned on.

Step 74, acquiring the voltage signal on the microphone pin.

And 75, identifying the type of the earphone plug according to the acquired voltage signal on the microphone pin.

As shown in fig. 8, the step 75 may specifically include:

and 751, judging whether the acquired voltage value of the voltage signal on the microphone pin is smaller than a first preset threshold value. If the voltage value of the voltage signal at the microphone pin is smaller than the first preset threshold, go to step 752. If the voltage value of the voltage signal at the microphone pin is greater than or equal to the first preset threshold, step 753 is executed.

Step 752, identify the headset plug as a three-segment headset plug.

When the voltage value of the voltage signal at the microphone pin is smaller than the first preset threshold value, the earphone plug is considered not to contain the microphone segment MIC, so that the microphone pin is pulled down to the ground by the inserted earphone plug, and therefore, the earphone plug is identified as a three-segment earphone plug.

And 753, continuously judging whether the voltage value of the voltage signal on the microphone pin is smaller than a second preset threshold value. If the voltage value of the voltage signal at the microphone pin is smaller than the second preset threshold, step 754 is executed. If the voltage value of the voltage signal at the microphone pin is greater than or equal to the second preset threshold, go to step 752.

Step 754, identifying the headset plug as a four-segment headset plug.

When the voltage value of the voltage signal at the microphone pin is greater than or equal to the first preset threshold value and less than the second preset threshold value, the earphone plug can be considered to include the microphone segment MIC, and therefore, the earphone plug is identified as a four-segment earphone plug.

When the voltage value of the voltage signal at the microphone pin is greater than or equal to the second preset threshold, the earphone plug may be considered as an abnormal earphone plug, for example, an earphone plug that is not matched with the earphone socket, and the abnormal earphone plug is identified as a three-segment earphone plug in the earphone identification logic. In this embodiment, after the earphone plug is identified as a three-section earphone plug, the controller further turns off the earphone bias voltage, and the microphone function cannot be normally used at the earphone end.

The first preset threshold is smaller than the second preset threshold, the second preset threshold may be, for example, 0.1V, the second preset threshold may be, for example, 2V, and the headphone bias voltage may be, for example, 2.8V.

Step 76, after completing the identification of the type of the headset plug, enabling the discharge circuit.

For details of the steps 71 to 76, reference may be made to the foregoing detailed description of the structure of the mobile device 100, which is not described herein again.

According to the earphone plugging noise elimination method, when the earphone plug is detected to be plugged, the discharge circuit of the microphone pin is disabled (namely, the quick discharge function of the microphone pin is closed), and then the earphone bias voltage is started, so that the microphone pin can be prevented from being repeatedly electrified and discharged in the plugging and identification processes of the earphone plug, and current noise caused by the generation of fluctuating voltage in the left and right sound channel circuits is avoided; the discharge circuit is enabled again (namely, the rapid discharge function of the microphone pin is started) after the identification process of the earphone plug is completed, so that the microphone pin can be discharged immediately when the earphone plug is pulled out, and the pulling-out noise generated in the pulling-out process of the earphone plug is avoided.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present application and not for limiting, and although the present application is described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present application without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A mobile device, comprising:

the earphone socket is internally provided with a microphone pin;

an earphone bias voltage circuit electrically connected to the microphone pin, the microphone pin receiving an earphone bias voltage through the earphone bias voltage circuit;

the discharge circuit is electrically connected with the microphone pin and is used for providing a discharge path for the microphone pin in a conducting state; and

the controller is used for disabling the discharging circuit, then starting the earphone bias voltage, then acquiring a voltage signal on the microphone pin, identifying the type of the earphone plug according to the acquired voltage signal, and enabling the discharging circuit after the type identification of the earphone plug is completed when the earphone plug is detected to be inserted into the earphone socket.

2. The mobile device of claim 1, wherein a left channel pin, a right channel pin, a ground pin, and a left detection pin are further disposed within the headset receptacle;

the mobile device further comprises an earphone plug noise elimination circuit, which comprises:

the discharge circuit;

the detection module is used for detecting the voltages on the left detection pin and the right channel pin and outputting corresponding detection signals; and

and the logic control module is electrically connected with the detection module and the discharge circuit respectively, and generates a corresponding logic control signal based on a detection signal output by the detection module so as to switch on or switch off the discharge circuit in an enabled state.

3. The mobile device of claim 2, wherein the logic control signal comprises a first logic signal and a second logic signal, wherein the logic control module is configured to generate the first logic signal when the detection module detects that the voltage at the left detection pin or the voltage at the right channel pin is at a high level, and the first logic signal is configured to turn on the discharge circuit in an enabled state to discharge the microphone pin through the discharge circuit; and

the logic control module is further configured to generate the second logic signal when the detection module detects that the voltage at the left detection pin and the voltage at the right channel pin are both low levels, where the second logic signal is used to disconnect the discharge circuit in an enabled state, so that the headphone bias voltage circuit can transmit a headphone bias voltage to the microphone pin.

4. The mobile device of claim 3, wherein the detection module comprises:

the first detection module is used for detecting the voltage on the left detection pin and outputting a first detection signal based on a first reference voltage and the voltage on the left detection pin; and

the second detection module is 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 with the output ends of the first detection module and the second detection module respectively, and generates corresponding logic control signals to switch on or switch off the discharge circuit in an enabling state based on the first detection signal and the second detection signal.

5. The mobile device of any one of claims 2-4, wherein the controller is electrically connected to an output of the logic control module, the controller detecting whether a headphone plug is inserted into the headphone jack based on a logic control signal generated by the logic control module.

6. The mobile device of any one of claims 2-4, further comprising an enable switch electrically connected to the controller and the discharge circuit, respectively, the controller 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 discharging circuit, or the enabling switch is electrically connected between the output end of the logic control module and the discharging circuit.

7. The mobile device of any of claims 2-4, wherein the left detection pin has an axial depth within the headset receptacle that is approximately equal to an axial depth of the left channel pin within the headset receptacle, and wherein the left detection pin contacts and electrically connects with a left channel segment of an externally inserted headset plug when the externally inserted headset plug is fully inserted into the headset receptacle.

8. The mobile device according to any one of claims 2 to 4, wherein 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 configured to turn on or off the discharge circuit, a control terminal of the control switch is electrically connected to an output terminal of the logic control module, and the logic control module generates a corresponding logic control signal to turn on or off the control switch based on the detection signal output by the detection module.

9. A headset plug noise cancellation method applied in a mobile device according to any one of claims 1 to 8, the headset plug noise cancellation method comprising:

detecting whether an earphone plug is inserted into the earphone socket;

if the earphone plug is detected to be inserted into the earphone socket, disabling a discharge circuit of a microphone pin, and then starting an earphone bias voltage;

acquiring a voltage signal on the microphone pin, and identifying the type of the earphone plug according to the acquired voltage signal on the microphone pin;

after completing the type recognition of the earphone plug, enabling the discharge circuit.

10. The method of claim 9, wherein identifying the type of the headset plug from the acquired voltage signal on the microphone pin comprises:

judging whether the voltage value of the acquired voltage signal on the microphone pin is smaller than a first preset threshold value or not;

if the voltage value of the voltage signal on the microphone pin is smaller than the first preset threshold value, identifying the earphone plug as a three-section type earphone plug;

if the voltage value of the voltage signal on the microphone pin is greater than or equal to the first preset threshold, continuously judging 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 smaller than the second preset threshold value, identifying the earphone plug as a four-section type earphone plug;

and if the voltage value of the voltage signal on the microphone pin is greater than or equal to the second preset threshold value, identifying the earphone plug as a three-section type earphone plug.