Abstract:
An apparatus and method for determining a valid user input in an electronic device is provided. The electronic device generally includes a touch unit included in a touch input circuit, wherein the touch unit corresponds to a touch area, a signal generator configured to transmit a signal to a first signal line and a second signal line by generating the signal, a signal measuring device configured to measure a part of a modified signal based on the transmitted signal, and a signal determiner configured to determine whether a user input is provided to the touch area based on the measured signal. The first signal line connects the signal generator and the touch unit, and the second signal line extends from the signal generator and is parallel with the first signal line.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit under 35 U.S.C. §19(a) of a Korean patent application filed on Jun. 30, 2015 in the Korean Intellectual Property Office and assigned Serial number 10-2015-0093163, the entire disclosure of which is hereby incorporated by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to an electronic device for determining a valid user input. More particularly, the present disclosure relates to an electronic device with a touch screen or display, and a method of detecting a valid user input to the touch screen or display. 
       BACKGROUND 
       [0003]    With the development of electronic technology, various electronic devices including a television (TV), a desktop, a notebook, a mobile phone, a Moving Picture Experts Group phase 1 or phase 2 (MPEG-1 or MPEG-2) audio layer 3 (MP3) player, and so on have emerged, and electronic devices having performed typically one-directional functions have gradually evolved to perform bi-directional functions based on interaction with users. To this end, various electronic devices have adopted various user interfaces receiving user inputs. 
         [0004]    As user interfaces of typical computers, keyboards and mice have been used, and with the development of technology, touch panels have developed. Currently various electronic devices including smartphones are focused on mobility and therefore touch panels with reduced weight are being adopted. 
         [0005]    The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure. 
       SUMMARY 
       [0006]    Aspects of the present disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide an electronic device for determining a valid user input. However, technical issues of the present disclosure are not limited to those described above and other technical issues will be clearly understood by those skilled in the art from the following description. 
         [0007]    In accordance with an aspect of the present disclosure, an electronic device is provided. The electronic device generally includes a touch unit (e.g., touch display), a signal generating unit (signal generator) configured to generate a signal and to transmit the signal to a first signal line and a second signal line, a signal measuring unit (signal measuring device) configured to measure at least a part of modified signal based on the transmitted signal, and a signal determining unit (signal determiner) configured to determine whether a user input is provided to the touch display based on the measured signal, wherein the first signal line connects the signal generator and the touch display, and the second signal line extends from the signal generator and is parallel with the first signal line. 
         [0008]    Both terminals of the signal measuring device may be respectively connected to a signal line extending from a node on the first signal line in parallel with the signal generator and to a signal line extending from a node on the second signal line in parallel with the signal generator, a resistor may be disposed between the node on the first signal line and the signal generator, and another resistor may be disposed between the node on the second signal line and the signal generator. 
         [0009]    The measured signal may represent a difference between a voltage value of the node on the first signal line and a voltage value of the node on the second signal line. 
         [0010]    The signal determiner may determine, from a voltage value of the measured signal, whether the user input is provided. 
         [0011]    The second signal line may not be connected to the touch display. 
         [0012]    The first signal line and the second signal line may be wired on a flexible printed circuit board (FPCB), and the first signal line and the second signal line include capacitors corresponding to the FPCB. 
         [0013]    The modified signal may be the signal modified based on charging and discharging operations. 
         [0014]    The second signal line may extend from the signal generator to be grounded so as to abut on a node at which the first signal line and the touch display are connected. 
         [0015]    The signal measuring device may include a first signal measuring device and a second signal measuring device, the first signal measuring device may be connected to a signal line extending from a node on the first signal line in parallel with the signal generator, the second signal measuring device may be connected to a signal line extending from a node on the second signal line in parallel with the signal generator, a resistor may be disposed between the node on the first signal line and the signal generator, and a resistor may be disposed between the node on the second signal line and the signal generator. 
         [0016]    The signal determiner may determine whether the user input is received by comparing pulse widths of signals respectively measured by the first and second signal measuring devices. 
         [0017]    Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
           [0019]      FIG. 1  illustrates an electronic device and a touch input circuit coupled to at least a portion of the electronic device according to various embodiments of the present disclosure; 
           [0020]      FIG. 2  illustrates a resistor-capacitor (RC) circuit for determining a touch input according to various embodiments of the present disclosure; 
           [0021]      FIG. 3  is a graph for comparing a signal in a case where there is a touch input with a signal with another case where there is no touch input in the RC circuit illustrated in  FIG. 2  according to various embodiments of the present disclosure; 
           [0022]      FIG. 4  illustrates a touch input circuit of an electronic device according to various embodiments of the present disclosure; 
           [0023]      FIGS. 5A and 5B  are graphs illustrating signals measured for a valid user input and for an invalid user input in by the touch input circuit of  FIG. 4  according to various embodiments of the present disclosure; 
           [0024]      FIG. 6  illustrates a touch input circuit of an electronic device according to other various embodiments of the present disclosure; and 
           [0025]      FIGS. 7A and 7B  are graphs illustrating signals measured for a valid user input and for an invalid user input by the touch input circuit of  FIG. 6  according to various embodiments of the present disclosure. 
       
    
    
       [0026]    Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
       DETAILED DESCRIPTION 
       [0027]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
         [0028]    The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents. 
         [0029]    It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
         [0030]    The term “include,” “comprise,” and “have”, or “may include,” or “may comprise” and “may have” used herein indicates disclosed functions, operations, or existence of elements but does not exclude other functions, operations or elements. Additionally, in various embodiments of the present disclosure, the term “include,” “comprise,” “including,” or “comprising,” specifies a property, a region, a fixed number, a process, an element and/or a component but does not exclude other properties, regions, fixed numbers, processes, elements and/or components. 
         [0031]    In various embodiments of the present disclosure, expression “A or B” or “at least one of A and/or B” may include all possible combinations of items listed together. For instance, the expression “A or B”, or “at least one of A and/or B” may indicate include A. B, or both A and B. 
         [0032]    The terms such as “1st”, “2nd”, “first”, “second”, and the like used herein may refer to modifying various different elements of various embodiments of the present disclosure, but do not limit the elements. For instance, such expressions do not limit the order and/or importance of corresponding components. The expressions may be used to distinguish one element from another element. For instance, both “a first user device” and “a second user device” indicate a user device and indicate different user devices from each other. For example, a first component may be referred to as a second component and vice versa without departing from the scope of the present disclosure. 
         [0033]    In this disclosure below, when one part (or element, device, etc.) is referred to as being “connected” to another part (or element, device, etc.), it should be understood that the former can be “directly connected” to the latter, or “connected” to the latter via an intervening part (or element, device, etc.). In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
         [0034]    Unless otherwise indicated herein, all the terms used herein, which include technical or scientific terms, may have the same meaning that is generally understood by a person skilled in the art. In general, the terms defined in the dictionary should be considered to have the same meaning as the contextual meaning of the related art, and, unless clearly defined herein, should not be understood abnormally or as having an excessively formal meaning. 
         [0035]    An electronic device according to various embodiments of the present disclosure may include at least one of a smartphone, a tablet personal computer (PC), a mobile phone, a video telephone, an electronic book reader, a desktop PC, a laptop PC, a netbook computer, a workstation, a server, a personal digital assistant (PDA), a portable multimedia player (PMP), a Moving Picture Experts Group phase 1 or phase 2 (MPEG-1 or IMPEG-2) audio layer 3 (MP3) player, a mobile medical device, a camera, or a wearable device. The wearable device may include at least one of an accessory-type device (e.g., a watch, a ring, a bracelet, an anklet, a necklace, glasses, a contact lens, a head-mounted device (HMD)), a textile- or clothing-integrated-type device (e.g., an electronic apparel), a body-attached-type device (e.g., a skin pad or a tattoo), or a bio-implantable-type device (e.g., an implantable circuit) 
         [0036]    In various embodiments of the present disclosure, an electronic device may be a home appliance. The smart home appliance may include at least one of, for example, a television (TV), a digital versatile disc (DVD) player, an audio, a refrigerator, an air conditioner, a cleaner, an oven, a microwave oven, a washing machine, an air cleaner, a set-top box, a home automation control panel, a security control panel, a TV box (e.g., Samsung HomeSync™, Apple TV™, or Google TV™), a game console (e.g., Xbox™ or PlayStation™), an electronic dictionary, an electronic key, a camcorder, or an electronic picture frame. 
         [0037]    In other various embodiments of the present disclosure, an electronic device may include at least one of various medical devices (e.g., various portable medical measurement devices (e.g., a blood glucose measuring device, a heart rate measuring device, a blood pressure measuring device, a body temperature measuring device, or the like), a magnetic resonance angiography (MRA), a magnetic resonance imaging (MRI), a computed tomography (CT), a scanner, an ultrasonic device, or the like), a navigation device, a global navigation satellite system (GNSS), an event data recorder (EDR), a flight data recorder (FDR), a vehicle infotainment device, electronic equipment for vessels (e.g., a navigation system, a gyrocompass, or the like), avionics, a security device, a head unit for a vehicle, an industrial or home robot, an automated teller machine (ATM), a point of sales (POS) device of a store, or an Internet of things (IoT) device (e.g., a light bulb, various sensors, an electric or gas meter, a sprinkler, a fire alarm, a thermostat, a streetlamp, a toaster, exercise equipment, a hot water tank, a heater, a boiler, or the like). 
         [0038]    According to various embodiments of the present disclosure, an electronic device may include at least one of a part of furniture or a building/structure, an electronic board, an electronic signature receiving device, a projector, or a measuring instrument (e.g., a water meter, an electricity meter, a gas meter, a wave meter, or the like). An electronic device may be one or more combinations of the above-mentioned devices. An electronic device according to various embodiments of the present disclosure may be a flexible device. An electronic device according to an embodiment of the present disclosure is not limited to the above-mentioned devices, and may include new electronic devices with the development of new technology. 
         [0039]    Hereinafter, an electronic device according to various embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. The term “user” used herein may refer to a person who uses an electronic device or may refer to a device (e.g., an artificial intelligence electronic device) that uses an electronic device. 
         [0040]    Hereinafter description will be provided by exemplifying a smartphone as an electronic device according to various embodiments of the present disclosure in the accompanying drawings. 
         [0041]      FIG. 1  illustrates a front case of an electronic device  10  and a touch input circuit  100  coupled to a part of the front case of the electronic device  10  according to various embodiments of the present disclosure. 
         [0042]    Referring to an upper drawing of  FIG. 1 , in a lower portion of a front case of the electronic device  10 , there are a first touch region  11  operating through a touch input, a second touch region operating through a touch input, and a physical button  13  operating through a user input such as a click. 
         [0043]    Referring to a lower drawing of  FIG. 1 , a touch input circuit  100  may be disposed under the front case of the electronic device  10 . For example, the touch input circuit  100  may be located such that a first touch unit  110  is disposed under the first touch region  11 , a second touch unit  120  is disposed under the second touch region  12 , and a click unit  130  is disposed under the physical button  13 . 
         [0044]    The touch input circuit  100  may include the first touch unit  110 , the second touch unit  120 , the click unit  130 , a touch integrated circuit (IC)  140 , and a connector  150 . The touch IC  140  may determine whether a touch input is provided on the first touch region  11  through the first touch unit  110 . The touch IC  140  may determine whether a touch input is provided on the second touch region  12  through the second touch unit  120 . In addition, the touch IC  140  may determine whether the physical button  13  is pressed through the click unit  130 . An operation in which the touch IC  140  determines whether there is a touch input through the first touch unit  110  or the second touch unit  120  will be described in relation to  FIGS. 2 and 3 . 
         [0045]    According to an embodiment of the present disclosure, the connector  150  may be connected to a printed circuit board (not illustrated) of the electronic device  10 . Processors (not illustrated) of the touch IC  140  and the electronic device  10  may be electrically connected to each other and transmit/receive signals therebetween. For example, the touch IC  140  may transmit a determination result of whether there is a touch input to the processor. 
         [0046]    The touch input circuit  100  may be realized with a flexible printed circuit board (FPCB). Accordingly, wires respectively connecting the first touch unit  110 , the second touch unit  120 , the click unit  130 , the touch IC  140 , the first touch unit  110  and the touch IC  140 , the second touch unit  120  and the touch IC  140 , the click unit  130  and the touch IC  140  may be included in the FPCB. 
         [0047]    Previously, it was mentioned that the touch input circuit  100  may be stacked under the front case of the electronic device  10 . Although a length of the touch input circuit  100  is illustrated to be longer than a width of the electronic device  10  in  FIG. 1 , the FPCB has a flexible material and may be curved at one region  160 . Accordingly, even though the length of the touch input circuit  100  is longer than the width of the electronic device  10 , the touch input circuit  100  may be stacked on the rear surface of the front case of the electronic device  10 . 
         [0048]      FIG. 2  illustrates a resistor-capacitor (RC) circuit for determining a touch input according to an embodiment of the present disclosure. A node a may be connected to another suitable circuit and may receive a signal from the circuit. Hereinafter, it is assumed that the node a receives a rectangular wave signal. 
         [0049]    Referring to  FIG. 2 , capacitor C EX  and a switch SW illustrated on the left side of a node b show effects of a capacitor and a switch by an operation activated outside the electronic device  10 . For example, if a user&#39;s finger contacts the node b, a capacitor value generated by the user&#39;s finger may correspond to C EX . In addition, an operation in which the user&#39;s finger contacts the node b may correspond to a state where the switch SW is on, and an operation in which the user&#39;s finger is separated from the node b may correspond to a state where the switch SW is off. In this case, the node b may correspond to the first touch unit  110  or the second touch unit  120  illustrated in  FIG. 1 . 
         [0050]    Referring to  FIG. 2 , capacitor C FPCB  illustrated on the right side of the node b may represent a capacitor component existing on the FPCB on which the first touch unit  110  or the second touch unit  120  is arrayed. The capacitor component may be an independent capacitor element, or it may be a capacitor component generated from a wiring structure. According to an embodiment, C FPCB  may be a capacitor included in the first touch unit  110  or the second touch unit  120 . 
         [0051]      FIG. 3  is a graph for comparing a signal in a case where there is a touch input with a signal in a case where there is no touch input in the RC circuit illustrated in  FIG. 2  according to various embodiments of the present disclosure. A graph  310  may be a graph in a case where there is no touch input, and a graph  320  may be a graph in a case where there is a touch input. 
         [0052]    If there is a touch input, the user&#39;s finger or an electronic pen (e.g. a stylus) is a C EX  and may be connected to C FPCB  of a typical RC FPCB  circuit in parallel. If the capacitor is connected in parallel, a capacitance value of a synthetic capacitor C EQ  becomes a sum of each capacitance value of each capacitor. In other words, C EQ  may correspond to a sum of C EX  and C FCB . Accordingly, as the C EX  is added, a capacitance value of an RC EQ  circuit becomes greater than that of an RC FPCB  circuit before C EX  is added. 
         [0053]    Referring to  FIG. 3 , the graphs  310  and  320  show operations that capacitors are discharged for time B, after each of C FPCB  and C EQ  is charged. Comparing graphs  310  and  320  with each other, for a time taken to charge each capacitor to a certain voltage (a prescribed ratio of a maximum charge voltage), it may be seen that a circuit of graph  320  takes longer than a circuit of graph  310 . The charge time for each capacitor is related to a time constant of an RC circuit. At this point, the time constant of the RC circuit is a multiplication of values of R and C. In other words, the time constant of the graph  310  becomes a multiplication of R and C FPCB  and the time constant of the graph  320  becomes a multiplication of R and C EQ . 
         [0054]    It may be seen that as a C value of an RC circuit is larger, a time taken to charge the capacitor becomes longer, and a charge time for a case where there is a touch input is longer than that for a case where there is not a touch input. The touch IC  140  may determine, from a charge time of the capacitor, whether there is a touch input. 
         [0055]    In addition, a case where a charged C of the RC circuit is discharged may be similar to the operation that C is charged. For example, referring to the graphs  310  and  320 , it may be seen that a discharge speed in a case where the touch input does not occur is faster than that in a case where the touch input occurs. 
         [0056]    Besides a case where C EX  is generated from a user&#39;s touch (via the user&#39;s finger or by a stylus), even in a case where C EX  is generated due to the electronic device being pressed, the charge speed and discharge speed may be changed. In this case, the touch IC  140  may wrongly determine that a touch input was created by a user. 
         [0057]      FIG. 4  illustrates a touch input circuit of an electronic device according to various embodiments of the present disclosure. A signal generating unit (e.g. a touch drive)  410  may generate a rectangular wave signal and provide the generated rectangular signal to the outside. 
         [0058]    Referring to  FIG. 4 , each of a first signal line  402  and a second signal line  404  may be connected in parallel with the signal generating unit  410 . According to an embodiment, the first signal line  402  or the second signal line  404  may extend to one region  430  of the touch input circuit. For example, while the first signal line  402  is connected to the one region  430  of the touch input circuit  100 , the second signal line  404  may not be connected to the one region  430  of the touch input circuit. The one region  430  of the touch input circuit may correspond to the first touch unit  110 , the second touch unit  120 , and the click unit  130  of  FIG. 1 . 
         [0059]    The rectangular wave signal generated from the signal generating unit  410  may be transmitted to C FPCB  extending from the first signal line  402  via a resistor R on the first signal line  402 . As described above, C FPCB  may correspond to a capacitor component generated by the capacitor element and/or a wiring structure and so on in the touch input circuit  100 . In addition, if one or more of first to third switches SW 1 , SW 2 , and SW 3  are in a short-circuited state, the rectangular wave signal may be transmitted to a capacitor to which a corresponding switch is on among C EX1  to C EX3 . 
         [0060]    According to an embodiment, C EX1  and C EX2  may be capacitors induced by a user&#39;s finger. For example, if a touch input using the user&#39;s finger occurs for the first touch unit (e.g. the first touch unit  110  of  FIG. 1 ) corresponding to the one region  430  of the touch input circuit, a capacitor component of C EX1  may be generated. In addition, C EX2  may be generated when there is a touch input using the user&#39;s finger for the second touch unit (e.g. the second touch unit  120  of  FIG. 1 ). In addition, C EX3  may be a capacitor generated, when a force is applied from the outside and an appearance of the electronic device  10  or an interval between elements is changed. 
         [0061]    The rectangular wave signal generated from the signal generating unit  410  may be transmitted to C FPCB  extending from the second signal line  404  via the resistor R. In addition, if the third switch SW 3  is on, the rectangular wave signal may be transmitted to C EX3  extending from the second signal line  404 , C FPCB  and C EX3  extending from the first signal line  402  may be the same capacitors as C FPCB  and C EX3  extending from the second signal line  404 . For example, the first signal line  402  and the second signal line  404  may abut on each other to share C FPCB  and C EX3 . 
         [0062]    The resistor R and the capacitors C FPCB , C EX1 , C EX1 , and C EX3  connected to the first signal line  402 , which are viewed from the signal generating unit  410 , may be represented as an RC EQ  circuit. In addition, the resistor R and the capacitors C FPCB  and C EX3  connected to the second signal line  404 , which are viewed from the signal generating unit  410 , may be represented as an RC EQ  circuit. 
         [0063]    Referring to the first signal line  402 , a signal line extends from node a on the first signal line  402  to the signal measuring unit  420  in parallel with the signal generating unit  410 . In addition, referring to the second signal line  404 , a signal line extends from node b on the second signal line  404  to the signal measuring unit  420  in parallel with the signal generating unit  410 . According to an embodiment, the signal line extending from node a may be connected to a first polarity (e.g. a positive polarity) of the signal measuring unit  420 , and the signal line extending from node b may be connected to a second polarity (e.g. a negative polarity) of the signal measuring unit  420 . Accordingly, the signal measuring unit  420  may measure a voltage difference between node a and node b. 
         [0064]    According to an embodiment, the signal measuring unit  420  may independently measure the voltages of node a and node b. However, in relation to  FIG. 4 , a description will be provided such that the signal measuring unit  420  measures the voltage difference between node a and node b. In addition, the measured voltage difference between node a and node b will be described with reference to  FIGS. 5A and 5B . 
         [0065]      FIGS. 5A and 5B  are graphs illustrating signals measured for a valid user input and for an invalid user input in the signal measuring unit illustrated in  FIG. 4  according to various embodiments of the present disclosure. 
         [0066]      FIG. 5A  is a graph illustrating a voltage difference between node a and node b in a case where C EX1  is connected by a user&#39;s touch input. If C EX1  is connected by the user&#39;s touch input, an RC EQ  circuit corresponding to the first signal line  402  may become R(C FPCB //C EX1 ) and an RC EQ  circuit corresponding to the second line  404  may become the RC FPCB  circuit. Accordingly, a value of C EQ  corresponding to the first signal line  402  and a value of C EQ  corresponding to the second signal line  404  become different. According to the voltage dividing principle, comparing two RC EQ  circuits in which different C EQ s are connected to an identical R, different voltages may be developed across the capacitors. Accordingly, there occurs a meaningful voltage difference between node a and node b. In a case where C EX2  is connected to a circuit by a user&#39;s touch input (i.e., a case where a C EX2  component is generated) may be the same. 
         [0067]    According to an embodiment, the R value or the capacitance value of C FPCB  may be determined in order that a meaningful voltage difference  510  may be generated. 
         [0068]      FIG. 5B  is a graph illustrating a voltage difference between node a and node b in a case where C EX3  is connected by the electronic device being pressed. If C EX3  is connected by the electronic device being pressed, the RC EQ  circuit corresponding to the first signal line  402  may become an R(C FPCB //C EX3 ) circuit and the RC EQ  circuit corresponding to the second line  404  may also become the R (C FPCB //C EX3 ) circuit. Accordingly, since the C EQ  value corresponding to the first signal line  402  and the C EQ  value corresponding to the second signal line  404  are substantially the same, a meaningless voltage difference  520  may be generated between node a and node b. 
         [0069]    The operation for measuring whether the voltage difference  510  or  520  measured by the signal measuring unit  420  is meaningful or meaningless may be performed in the signal determining unit. The signal determining unit may correspond to the touch IC  140  of  FIG. 1 . Alternatively, the signal determining unit may be a module included in a touch IC, and the signal generating unit  410  and the signal measuring unit  420  may also be a module included in the touch IC. 
         [0070]    Although being illustrated like a pulse of a rectangular wave signal, the voltage differences  510  and  520  of  FIGS. 5A and 5B  may also appear as a type like the graph  310  or  320  of  FIG. 3 . 
         [0071]      FIG. 6  illustrates a touch input circuit of an electronic device according to another embodiment of the present disclosure. In relation to  FIG. 6 , descriptions identical, similar, or corresponding to those in relation to  FIG. 4  may be omitted. 
         [0072]    A signal generating unit (e.g. a touch drive)  610  may generate a signal, for example, a rectangular wave signal and may provide the generated rectangular wave signal outside of the signal generating unit  610 . Referring to  FIG. 6 , each of a first signal line  602  and a second signal line  604  may be connected in parallel with the signal generating unit  610 . In an embodiment, while the first signal line  602  is connected to one region  640  of the touch input circuit  100 , the second signal line  604  may not be connected to the one region  640  of the touch input circuit. The one region  640  of the touch input circuit may correspond to the first touch unit  110 , the second touch unit  120 , and the click unit  130  of  FIG. 1 . 
         [0073]    Referring to the first signal line  602 , the rectangular wave signal generated from the signal generating unit  610  may be transmitted to C FPCB  extending from the first signal line  602  via a resistor R on the first signal line  602 . As described above, C FPCB  may correspond to a capacitor component generated by a capacitor element and/or a wiring structure and so on in the touch input circuit  100 . In addition, if one or more of the first to third switches SW 1 , SW 2 , and SW 3  are on, the rectangular wave signal may be transmitted to a capacitor to which a corresponding switch is on among C EX1  to C EX3  extending from the first signal line  602 . 
         [0074]    The rectangular wave signal generated from the signal generating unit  610  may be transmitted via a resistor R to C FPCB  extending from the second signal line  604 . In addition, if the third switch SW 3  is on, the rectangular wave signal may be transmitted to C EX3  extending from the second signal line  604 . C FPCB  and C EX3  extending from the first signal line  602  may be the same as C FPCB  and C EX3  extending from the second signal lint  604 . For example, the first signal ling  602  and the second signal line  604  may abut on each other to share C FPCB  and C EX3 . 
         [0075]    The resistor R and the capacitors C FPCB , C EX1 , C EX1 , and C EX3  connected to the first signal line  602 , which are viewed from the signal generating unit  610 , may be represented as an RC EQ  circuit. In addition, the resistor R and the capacitors C FPCB  and C EX1  connected to the second signal line  604 , which are viewed from the signal generating unit  610 , may be represented as an RC EQ  circuit. 
         [0076]    Referring to the first signal line  602 , a signal line extends from node a on the first signal line  602  to the signal measuring unit  620  in parallel with the signal generating unit  610 . In addition, referring to the second signal line  604 , a signal line extends from node b on the second signal line  604  to the signal measuring unit  630  in parallel with the signal generating unit  610 . According to an embodiment, the first signal measuring unit  620  and the second signal measuring unit  630  respectively measure voltages of node a and node b according to a flow of time. Although  FIG. 6  illustrates the first and second signal measuring units  620  and  630  as independent components, in an embodiment, the first and second signal measuring units  620  and  630  may be realized as one signal measuring unit. 
         [0077]    The measured voltage difference between node a and node b will be described with reference to  FIGS. 7A and 7B . 
         [0078]      FIGS. 7A and 7B  are graphs illustrating signals respectively measured for a valid user input and for an invalid user input in the signal measuring units illustrated in  FIG. 6  according to another embodiment of the present disclosure. 
         [0079]      FIG. 7A  is a graph illustrating voltages at node a and node b in a case where C EX1  is connected by a user&#39;s touch input. A graph  710  is a voltage of node a measured by the first signal measuring unit  620 , and a graph  720  is a voltage of node b measured by the second signal measuring unit  630 . If C EX1  is connected by the user&#39;s touch input, an RC EQ  circuit corresponding to the first signal line  602  may become an R(C FPCB //C EX1 ) circuit and an RC EQ  circuit corresponding to the second line  604  may become an RC FPCB  circuit. Accordingly, a time constant of the RC EQ  circuit corresponding to the first signal line  602  and a time constant of the RC EQ  circuit corresponding to the second signal line  604  become different. As described in relation to  FIG. 3 , pulse widths of voltages of node a and node b may be different due to a time constant difference. The case where C EX2  is connected by a user&#39;s touch input may be the same. 
         [0080]      FIG. 7B  is a graph illustrating a voltage difference between node a and node b in a case where C EX3  is connected by the electronic device being pressed. A graph  730  is a voltage of node a measured by the first signal measuring unit  620 , and a graph  740  is a voltage of node b measured by the second signal measuring unit  630 . If C EX3  is connected by the electronic device being pressed, the RC EQ  circuit corresponding to the first signal line  602  may become an R(C FPCB //C EX3 ) circuit and the RC EQ  circuit corresponding to the second line  604  may also become the R(C FPCB //C EX3 ) circuit. Accordingly, since a C EQ  value corresponding to the first signal line  602  and a C EQ  value corresponding to the second signal line  604  are substantially the same, a time constant of the RC EQ  circuit corresponding to the first signal line  602  and a time constant of the RC EQ  circuit corresponding to the second signal line  604  may be the same. 
         [0081]    Accordingly, a meaningful voltage difference may be generated between node a and node b. Although  FIG. 7B  illustrates graphs  730  and  740  identically, according to an embodiment, there is a minute difference between the graphs  730  and  740 , which may be determined to be substantially the same. 
         [0082]    An operation for determining a valid user input and an invalid user input from a voltage value measured from the first and second signal measuring units  620  and  630  may be performed in the signal determining unit. The signal determining unit may correspond to the touch IC  140  of  FIG. 1 . Alternatively, the signal determining unit may be a module included in a touch IC, and the first and second signal measuring units  620  and  630  may also be modules included in the touch IC. 
         [0083]    Although being illustrated like a pulse of a rectangular wave signal, the voltage differences  710  and  720  of  FIG. 7A  may appear like the type of the graphs  310  or  320  of  FIG. 3 . 
         [0084]    A module or a program module according to various embodiments of the present disclosure may include at least one of the above-mentioned elements, or some elements may be omitted or other additional elements may be added. Operations performed by the module, the program module or other elements according to various embodiments of the present disclosure may be performed in a sequential, parallel, iterative or heuristic way. Furthermore, some operations may be performed in another order or may be omitted, or other operations may be added. 
         [0085]    While the present disclosure has been shown and described with reference to various 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 present disclosure as defined by the appended claims and their equivalents.