Abstract:
An apparatus and method for interfacing with an earphone are provided. The method includes checking if the earphone is uninstalled promptly after the connection of the earphone is sensed in an external port and if it is sensed that the earphone is uninstalled, continuing to apply a voltage to a MIC_BIAS terminal. The generation of a noise of the MIC_BIAS terminal caused by applying of a periodic voltage resulted from loose insertion of the earphone is prevented.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY 
       [0001]    The present application is related to and claims priority under 35 U.S.C. §119(a) to a Korean Patent Application No. 10-2012-0033388 filed on Mar. 30, 2012 in the Korean Intellectual Property Office, the contents of which are herein incorporated by reference. 
       TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to an apparatus and method for detecting an earphone applied to an electronic device. 
       BACKGROUND OF THE INVENTION 
       [0003]    Recently, as a multimedia technology is developed, an electronic device having various functions has appeared. As these devices, for example, there is a portable terminal mainly classified into a smart phone. These devices generally have a convergence function of complexly performing one or more functions. 
         [0004]    Particularly, a portable terminal, which is being recently launched, has a function capable of receiving airwave broadcasting (for example, terrestrial Digital Multimedia Broadcasting (DMB)) and playing back a music file or photographing and playing back a moving picture in high definition in addition to a basic calling function. 
         [0005]    When performing these various supplementary functions, a portable terminal additionally uses an earphone device (generally, called an ‘earphone’) including an earplug inserted into an ear jack hole of an ear jack provided in a corresponding device. In this earphone device, an earplug is provided at one end of a cable of a predetermined length, and a pair of earphones for listening to sound in stereo is installed at the other end thereof. Also, generally, a microphone is installed in a middle of the cable to perform a hands free function upon call. 
         [0006]    The aforementioned earplug generally uses a 3-pole or 4-pole terminal. Each terminal is installed in an electrical insulation state. If being connected to an ear jack, each terminal comes into contact with a corresponding pin installed in a corresponding location of the ear jack, whereby each terminal performs a corresponding function. 
         [0007]    For example, in a 3.5 pie 3-pole terminal of an earplug, a first terminal of the lowest side, a 2nd terminal of the top thereof, and a 3rd terminal of the top thereof, which take charge of SPK_L, SPK_R, and GND, respectively, are electrically connected with corresponding pins of an ear jack and perform functions. 
         [0008]    Also, in a 4-pole terminal of the earplug, a first terminal of the lowest side, a 2nd terminal of the top thereof, a 3rd terminal of the top thereof, and a 4th terminal of the top thereof are electrically connected with corresponding pins of the ear jack, which take charge of SPK_L, SPK_R, GND, and MIC, respectively, and perform functions. 
         [0009]    An ear jack for housing an earplug as described above is of a construction of connecting corresponding terminals of the earplug correspondingly to a plurality of pins installed in different locations within one housing. This can cause a detection error problem in course of inserting the earplug into the ear jack. 
         [0010]    For instance, a sense pin for sensing the insertion or non-insertion of the earplug is installed at a housing end of the ear jack. Although the earplug is not fully (i.e., loosely) inserted into the ear jack, if a SPK_L terminal of the earplug gets into contact with the sense pin, a portable terminal detects the insertion of an earphone. But in this case, because the earphone is inserted into the portable terminal, the portable terminal detects a low signal by the sense pin. Due to this, the portable terminal supplies a voltage to a MIC_Bias terminal in order to check the insertion or non-insertion of a microphone. But, because the MIC terminal has not been connected with a MIC pin of the ear jack, the voltage applied to the MIC_Bias terminal is floated and is again applied to the SPK_L terminal and the sense pin. Due to this, the sense pin receives a high signal applied and detects as the earplug is uninstalled. Accordingly, the portable terminal eliminates the voltage applied to the MIC_Bias terminal. Due to this, the sense pin again receives a low signal applied and detects as the earplug is again inserted. 
         [0011]    That is, in a state where the earplug is not fully inserted into the ear jack but the SPK_L terminal comes into contact with the sense pin, the portable terminal repeatedly performs the aforementioned operation. During this process, a periodic noise of 8 Hertz (Hz) interval is generated. This not only has given a feeling of displeasure to a user but also has become the cause of erroneous operation. 
       SUMMARY OF THE INVENTION 
       [0012]    To address the above-discussed deficiencies of the prior art, it is a primary object to provide an apparatus and method for interfacing with an earphone in an electronic device, when an earplug is loosely inserted into an ear jack, enabling a user to detect this and insert it completely. 
         [0013]    Another aspect of the present disclosure is to provide an apparatus and method for interfacing with an earphone in an electronic device when an earplug has been loosely inserted into an ear jack, which remove noise generation and prevent an erroneous operation of the electronic device in advance. 
         [0014]    A further aspect of the present disclosure is to provide an apparatus and method for interfacing an earphone in an electronic device, which notify a user of this state through a display unit of the electronic device and improve a convenience of use of the electronic device when an earplug is loosely inserted into an ear jack and a predetermined time lapses. 
         [0015]    The above aspects are achieved by providing an apparatus and method for detecting an earphone in an electronic device. 
         [0016]    According to one aspect of the present disclosure, an apparatus for detecting an earphone in an electronic device is provided. The apparatus includes an external port to interface with the earphone, and at least one processor for controlling to apply a voltage to a MIC_BIAS terminal if connection of the earphone to the external port is sensed, and although disconnection of the earphone is again sensed, controlling to apply and not to turn off a voltage to the MIC_BIAS terminal. The generation of a noise of the MIC_BIAS terminal caused by applying of a periodic voltage resulted from loose insertion of the earphone is prevented. 
         [0017]    According to another aspect of the present disclosure, a method for detecting an earphone in an electronic device is provided. The method includes checking if the earphone is uninstalled promptly after the connection of the earphone is sensed in an external port and if it is sensed that the earphone is uninstalled, continuing to apply and not turning off a voltage to a MIC_BIAS terminal. The generation of a noise of the MIC_BIAS terminal caused by applying of a periodic voltage resulting from loose insertion of the earphone is prevented. 
         [0018]    Also, an output means of an electronic device is controlled so that a user can detect the loose insertion of an earphone. For example, if the loose insertion of the earphone is sensed, the electronic device can display an error message on a display unit, and can output a sound through a sound output means such as a speaker, thereby being capable of allowing the user to be notified an error. Further, the electronic device may output the error message and the error sound together. 
         [0019]    Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
           [0021]      FIG. 1  is a perspective view illustrating an electronic device with an earphone detection unit according to an exemplary embodiment of the present disclosure; 
           [0022]      FIG. 2  is a cross-sectional diagram illustrating an earplug of an earphone loosely inserted into the ear jack of the electronic device; 
           [0023]      FIG. 3  is a block diagram illustrating a construction of an electronic device according to an exemplary embodiment of the present disclosure; 
           [0024]      FIG. 4  is a circuit diagram illustrating an apparatus for detecting an earphone in an electronic device according to an exemplary embodiment of the present disclosure; 
           [0025]      FIG. 5  is a flowchart illustrating a method for detecting an earphone in an electronic device according to an exemplary embodiment of the present disclosure; 
           [0026]      FIG. 6A  is an exemplary normal operation code resulting from earphone detection of an electronic device according to an exemplary embodiment of the present disclosure and  FIG. 6B  is an exemplary erroneous operation code resulting from conventional loose insertion; and 
           [0027]      FIG. 7  is a diagram illustrating a scene for informing a user of a state in which an earplug of an earphone is loosely inserted in an electronic device according to an exemplary embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]      FIGS. 1 through 7 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged electric device. Preferred embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the disclosure in unnecessary detail. And, terms described below, which are defined considering functions in the present disclosure, can be different determining on user and operator&#39;s intention or practice. Therefore, the terms should be defined on the basis of the disclosure throughout this specification. 
         [0029]    The present disclosure directs a portable terminal as an electronic device and an earphone device applied to the portable terminal. But, the present disclosure is not limited to this, and would be applicable to the electronic device, for example, various devices to which an earphone is applicable, such as a Personal Digital Assistant (PDA), a laptop computer, a smart phone, a netbook, a Mobile Internet Device (MID), a Ultra Mobile Personal Computer (UMPC), a table PC, a navigator, an MPEG audio layer 3 (MP3) player and the like. 
         [0030]      FIG. 1  is a perspective view illustrating an electronic device  300  including an earphone detection apparatus according to a desirable exemplary embodiment of the present disclosure and an earphone device  6 . 
         [0031]    Referring to  FIG. 1 , the electronic device  300  includes a display unit  302  installed in a front surface  301 , an earpiece  303  installed at a top side of the display unit  302 , and a microphone  304  installed at a bottom side of the display unit  302 . Also, the electronic device  300  has an ear jack  10  installed in its suitable place for receiving an earplug  30  of the earphone  6 . 
         [0032]    According to the present disclosure, when the earplug  30  of the earphone  6  is not fully inserted, i.e., is loosely inserted into the ear jack  10 , if a predetermined time lapses, an error message is displayed on the display unit  302 . But, the present disclosure is not limited to this, and can use a sound output means such as a speaker for generating an error sound. Alternatively, an error message and an error sound can be output simultaneously. Accordingly, a user will be able to view the error message or listen to the error sound and fully install or uninstall the earphone  6 . 
         [0033]    Also, if a predetermined time lapses after an error message is displayed or an error sound is output, the error message can be erased or the error sound output from the sound output means can be removed. Desirably, if it is sensed that the earphone is fully uninstalled from the ear jack or is fully normally inserted into the ear jack, the output of the error message or sound can be removed. 
         [0034]      FIG. 2  is a cross-sectional diagram illustrating a principal part of an ear jack  10  of an electronic device  300  and an earplug  30  of an earphone  6  loosely inserted into the ear jack  10 . A 4-pole earplug is described as an example only. 
         [0035]    Referring to  FIG. 2 , a first terminal  32  of the lowest side of the earplug  30 , a second terminal  33  on the top thereof, a third terminal  34  on the top thereof, and a fourth terminal  35  on the top thereof correspond to SPK_L, SPK_R, GND, and MIC, respectively. The first terminal  32 , the second terminal  33 , the third terminal  34 , and the fourth terminal  35  are arranged correspondingly to a SPK_L pin  112 , a SPK_R pin  113 , a GND pin  114 , and a MIC pin  115  sequentially protrusively installed within a space  111  of a housing  11  constructing the ear jack  10 . Accordingly, if the earplug  30  is fully inserted into the space  111  of the ear jack housing  11 , the SPK_L terminal  32  of the earplug  30 , the SPK_R terminal  33 , the GND terminal  34 , and the MIC terminal  35  are connected correspondingly to the SPK_L pin  112  of the ear jack  10 , the SPK_R pin  113 , the GND pin  114  and the MIC pin  115 . In an exemplary embodiment, a sense pin  116 , which is installed in the housing  11  of the ear jack  10 , also comes into contact with the SPK_L terminal  32  and senses the insertion or non-insertion of the earphone  6 . 
         [0036]    But, although the earplug  30  is not fully inserted into the ear jack  10  of the electronic device  300  as illustrated in  FIG. 2 , the electronic device  300  senses a state in which the SPK_L terminal  32  is inserted and connected to the SPK_L pin  112  and the sense pin  116 . In this case, because the earphone  6  has been inserted, the electronic device  300  detects a low signal at the sense pin  116 . Owing to this, the electronic device  300  supplies a voltage to a MIC_Bias terminal to check the insertion or non-insertion of a microphone. But, the voltage applied to the MIC_Bias terminal is floated because the MIC terminal  35  has not been connected with the MIC pin  115  of the ear jack  10 , so the voltage supplied to the MIC_Bias terminal is applied to the SPK_L pin  112  and the sense pin  116 . Due to this, the sense pin  116  receives a high signal applied and detects as if the earplug  30  is uninstalled from the ear jack  10 . Accordingly, the electronic device  300  removes the voltage applied to the MIC_Bias terminal. Due to this, the sense pin  116  again receives a low signal applied and again detects as if the earplug  30  is inserted into the ear jack  10 . The repetitions of the process generate a noise. 
         [0037]    To address the aforementioned problem, in the present disclosure, when the earplug  30  is fully inserted from the loose insertion state and a low signal is sensed and, in a state where a voltage is supplied to the MIC_Bias terminal, the electronic device  300  does not turn off the MIC_Bias terminal and if a predetermined time lapses, the electronic device  300  displays an error message on the display unit  302  of the electronic device  300 . Accordingly, if a user viewing this error message fully inserts the earplug  30  into the ear jack  10 , the electronic device  300  determines one of a 3-pole or 4-pole of the earplug  30  based on the low voltage or high voltage applied to the MIC_Bias terminal, and performs a normal operation. 
         [0038]      FIG. 3  is a block diagram illustrating a construction of an electronic device according to an exemplary embodiment of the present disclosure. Referring to  FIG. 3 , the electronic device includes a storage module  310 , a processor unit  320 , a communication system  330 , an external port  350 , an audio processor  340 , an Input/Output (I/O) control module  360 , a display unit  302 , and an input device  380 . Here, the storage module  310  and the external port  350  may exist in plural. The display unit  302 , which is a display module, can include a display module of a touch screen scheme. Also, the external port  350  can be an ear jack  10  for electrically being connected with an earplug  30  of an earphone  6  according to one embodiment of the present disclosure. Also, the external port  350  including the ear jack  10  can include signal paths of a 3.5_DETECT terminal (denoted by reference numeral  353  in  FIG. 4 ) to which a signal of the earplug  30  is applied and an EARMIC_P terminal (denoted by reference numeral  357  in  FIG. 4 ) to which a MIC signal is applied. 
         [0039]    The processor unit  320  includes a memory interface  321 , a processor  322  and a peripheral interface  323 . Here, the processor  321  can exist in plural. Also, the peripheral interface  323  can include a base band module  324  which receives transmission of an applied signal from the earplug  30  and in response to this, forwards a signal to a controller. 
         [0040]    The communication system  330  can include a Radio Frequency (RF) processor and an antenna unit, although not illustrated. 
         [0041]    The aforementioned constituent elements can be realized in hardware such as one or more integrated circuits, software, or in combination of hardware and software. 
         [0042]    Each constituent element is described as follows. 
         [0043]    The storage module  310  can include a data storage unit  311  and a program storage unit  312 . The data storage unit  311  stores data generated during execution of a program. The program storage unit  312  stores a program for controlling an operation of the portable terminal. For example, the program storage unit  312  can include an Operating System (OS) software module  313 , a communication software module  314 , a graphic software module  315 , a user interface software module  316 , a transmission control module  317 , a camera module  318 , an application module  319  and the like. 
         [0044]    The OS software module  313  includes at least one software constituent element for controlling general system operation. In an exemplary embodiment, the OS software module  313  performs a function of making smooth communication between a plurality of hardware (device) and software constituent elements. 
         [0045]    The communication software module  314  includes at least one software constituent element for processing data that is transmitted/received through the RF processor or the external port  350 . The graphic software module  315  includes at least one software constituent element for providing and displaying a graphic on the display unit  302 . The user interface module  316  includes at least one software constituent element related to a user interface. The application module  319  includes a software constituent element for at least one application installed in the electronic device  300 . 
         [0046]    The transmission control module  317  includes a software constituent element for transmitting or receiving data related to the electronic device  300 . The camera module  318  includes a software constituent element for general operation of a camera system  390  of the electronic device  300 . 
         [0047]    The memory interface  321  of the processor unit  320  controls the access of other constituent elements, such as the processor  322  and the peripheral interface  323 , to the storage module  310 . Also, the processor unit  320  analyzes a signal applied from the base band module  323  and sets a timer with a predetermined time and, if the loose insertion of the earplug  30  is sensed, the processor unit  320  controls to output an error message to the display unit  302  after the lapse of the predetermined time. 
         [0048]    Further, if the loose insertion of the earplug  30  is sensed, the processor unit  320  controls to disconnect the voltage applied to a MIC_Bias terminal, preventing the generation of a noise resulted from a repeated connection/disconnection to the earplug  30 . The processor  322  controls the electronic device  300  to provide various services such as voice communication and data communication using at least one software program. Also, the processor  322  may control to execute a software module stored in the storage module  310  and provide a multimedia service corresponding to the software module. The memory interface  321 , the processor  322 , and the peripheral interface  323 , which are included in the processor unit  320 , can be realized in a single chip or a separate chip. 
         [0049]    The RF processor of the communication system  330  processes an RF signal transmitted/received through an antenna. For example, the RF processor includes an RF transceiver, an amplifier, a tuner, an oscillator, a Digital Signal Processor (DSP), a COding DECoding (CODEC) chip set, a Subscriber Identity Module (SIM) card and the like. The external port  350  includes a connection interface for the portable terminal to direct connect with other devices such as an earphone or connect with other devices through a network. For example, the external port  350  may include a charging interface for charging of the electronic device. The audio processor  340  forms an audio packet between a user and the electronic device  300  through a speaker  341  and a microphone  342 , and provides an audio interface. 
         [0050]    The I/O control module  360  provides interface between the display unit  302  including the display module and the input device  380  such as a key button, and the peripheral interface  323 . 
         [0051]      FIG. 4  is a high-level circuit diagram illustrating an apparatus for detecting an earphone in an electronic device according to an exemplary embodiment of the present disclosure. Referring to  FIG. 4 , the electronic device  300  for earphone detection includes a base band module  324  and a plurality of circuit elements for detecting an earphone  6 . Here, the base band module  324  includes a General Purpose Input Output Pin (GPIO)  325  and an audio block  326 . The plurality of circuit elements is described below. 
         [0052]    First, a 3.5_DETECT terminal  353  of the electronic device  300  performs a function of providing a signal, which represents if the earphone  6  is connected to an ear jack  10 , to the GPIO  325  of the base band module  324 . That is, when the earphone  6  is not connected, the 3.5_DETECT terminal  353  maintains a low level and provides a voltage lower than a programmable reference voltage  3513  to a first comparator  3512 . In contrast, when the earphone  6  is connected, the 3.5_DETECT terminal  353  maintains a high level and provides a voltage higher than the programmable reference voltage  3513  to the first comparator  3512 . Here, the programmable reference voltage  3513  of the first comparator  3512  is set by a developer. 
         [0053]    When the earphone  6  is not connected, the first comparator  3512  receives an input of the voltage lower than the programmable reference voltage  3513  from the 3.5_DETECT terminal  353 , and outputs a low signal to a first inverter  3511 . In contrast, when the earphone  6  is connected, the first comparator  3512  receives an input of the voltage higher than the programmable reference voltage  3513  from the 3.5_DETECT terminal  353 , and outputs a high signal to the first inverter  3511 . 
         [0054]    The first inverter  3511  inverts a high signal input from the first comparator  3512  to a low signal or inverts a low signal from the first comparator  3512  to a high signal to output the high signal or low signal to the GPIO  325  of the base band module  324 . That is, when the earphone  6  is not connected, the first inverter  3511  receives an input of a low signal from the first comparator  3512 , inverts the low signal to a high signal, and outputs the high signal to the GPIO  325 . In contrast, when the earphone  6  is connected, the first inverter  3511  receives an input of a high signal from the first comparator  3152 , inverts the high signal to a low signal, and outputs the low signal to the GPIO  325 . 
         [0055]    The GPIO  325  of the base band module  324  determines if the earphone  6  is connected using a signal input from the first inverter  3511 . That is, when a high signal is input from the first inverter  3511 , the GPIO  325  determines that the earphone  6  has not been connected. In contrast, when a low signal is input from the first inverter  3511 , the GPIO  325  determines that the earphone  6  has been connected. 
         [0056]    Also, the GPIO  325  determines if the earphone  6  connected to the electronic device  300  is a 3-pole earphone or a 4-pole earphone using a signal input from the 2nd inverter  3521 . When the earphone  6  is the 4-pole earphone, the GPIO  325  processes a function for sensing if a SEND/END key is input and performing a corresponding operation. 
         [0057]    When the 3-pole earphone is connected, the second comparator  3522  receives an input of a voltage lower than a programmable reference voltage  3523  from an EAR_KEY terminal  354 , and outputs a low signal to a 2nd inverter  3521 . In contrast, when the 4-pole earphone is connected, the second comparator  3522  receives an input of a voltage higher than the programmable reference voltage  3523  from the EAR_KEY terminal  354 , and outputs a high signal to the second inverter  3521 . Here, the programmable reference voltage  3523  is set by the developer. Also, when a SEND/END key of the 4-pole earphone is input, the second comparator  3522  receives an input of a voltage lower than the programmable reference voltage  3523  from the EAR_KEY terminal  354 , and outputs a low signal to the 2nd inverter  3521 . 
         [0058]    The 2nd inverter  3521  inverts a high signal input from the second comparator  3522  to a low signal or inverts a low signal input from the second comparator  3522  to a high signal to output the low signal or the high signal to the GPIO  325  of the base band module  324 . 
         [0059]    That is, in a state where a low signal is input from the first inverter  3511 , when a high signal is input from the second inverter  3521 , the GPIO  325  determines that the 3-pole earphone has been connected. In contrast, in the state where the low signal is input from the first inverter  3511 , when a low signal is input from the 2nd inverter  3521 , the GPIO  325  determines that the O-pole earphone has been connected. Here, when it is determined that the 4-pole earphone has been connected through the first inverter  3511  and the second inverter  3521 , if a low signal from the second inverter  3521  is changed to a high level and then is changed to a low level, the GPIO  325  determines that a SEND/END key of the 4-pole earphone has been input, and performs a switching function for operating the audio block  326 . 
         [0060]    Also, the audio block  326  of the base band module  324  receives a microphone signal from the earphone  6  of the electronic device  300  through the EARMIC_P terminal  357 , and processes the microphone signal. 
         [0061]    When the 4-pole earphone is connected and the SEND/END key of the 4-pole earphone is input, the EARMIC_P terminal  357  receives a user voice signal from the 4-pole earphone and provides the voice signal to the audio block  326 . 
         [0062]    Also, when the earplug  30  is loosely inserted into the ear jack  10  and the 3.5 DETECT terminal  353  is inverted from a low level to a high level, the base band module  324  does not turn off the voltage applied and continues to apply it to a MIC_BIAS terminal  355  under control of the processor unit  320 . Also, from this point, the processor unit  320  set a timer with a predetermined time and, if a predetermined time lapses, the processor unit  320  outputs an error message resulted from the loose insertion of the earplug  30 , to a display unit  320  of the electronic device  300 . 
         [0063]    The aforementioned earphone detection process in the electronic device is described below in detail. 
         [0064]      FIG. 5  is a flowchart illustrating a method for detecting an earphone in an electronic device according to an exemplary embodiment of the present disclosure.  FIG. 6  is a diagram illustrating a normal operation code resulting from earphone detection of the electronic device according to one exemplary embodiment of the present disclosure and an erroneous operation code resulting from conventional loose insertion.  FIG. 7  is a diagram illustrating a scene for informing a user of a state in which an earplug of the earphone is loosely inserted in the electronic device according to the exemplary embodiment of the present disclosure. 
         [0065]    The method for detecting the earphone in the electronic device according to the present disclosure is described as follows. 
         [0066]    First, in step  501 , the electronic device checks if an earphone has been inserted. If it is checked in step  501  that the earphone has been inserted, in step  503 , the electronic device applies a predetermined voltage to a MIC_Bias terminal so as to check if an inserted earplug is a 3-pole terminal or a 4-pole terminal. In an exemplary embodiment, when the earphone has not been connected, the electronic device provides a high signal to a base band module and, when the earphone has been connected, the electronic device provides a low signal to the base band module, whereby a processor unit can sense a connection state of the earphone. 
         [0067]    After that, in step  505 , the electronic device checks if the earphone has been again uninstalled. That is, when it is checked that, owing to the loose insertion of the earplug, a GND terminal is floated, the voltage applied to the MIC_Bias terminal is applied to a 3.5 DETECT terminal, and a high signal is provided to the base band module, the processor unit proceeds to step  507  and does not turn off the voltage applied to the MIC_Bias terminal and maintains a state thereof. Simultaneously, the electronic device drives a timer. Accordingly, by not turning off the voltage applied to the MIC_Bias terminal as above, the processor unit can perform a normal operation as illustrated in  FIG. 6B  unlike  FIG. 6A . 
         [0068]    Next, if a predetermined time lapses in step  509 , the processor unit displays an error message on a display unit  302  of the electronic device  300  in step  510 . For example, the error message can be a message  305 , “Please fully insert or reject your headphone” on the display unit  302  of the electronic device  300  as illustrated in  FIG. 7 . 
         [0069]    In contrast, after the error message is displayed, if a user fully inserts the earplug of the earphone into the ear jack  10  of the electronic device  300 , in step  511 , the processor unit checks if an EAR_KEY_INT terminal is changed to a low level. If it is checked in step  511  that EAR_KEY_INT terminal is changed to the low level, the processor unit proceeds to step  513  and detects as the earphone has a 4-pole earplug. 
         [0000]    If it is checked in step  515  that the EAR_KEYINT terminal is changed to a high level, the processor unit proceeds to step  517  and detects as the earphone has a 3-pole earplug. 
         [0070]    Although not illustrated, if a user fully removes the earplug from the ear jack after detects the error message, a MIC terminal comes into contacts with a GND terminal of the ear jack during the removal and a voltage applied to the MIC_Bias terminal drops, whereby the separation of the ear jack can be detected. 
         [0071]    According to the present disclosure, there is an effect of, although an earplug of an earphone is loosely inserted into an ear jack of an electronic device, being able to preventing the generation of a noise and, by previously notifying a user of this state, being able to increase a convenience of use of the electronic device. 
         [0072]    While the disclosure has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.