Abstract:
A method and an apparatus for reducing electromagnetic waves in a mobile device are provided. According to the method, in a mobile device having the first and second modules with different functions, the apparatus operates the first module at the first operating frequency. If there is a request for operating the second module while the first module is operated, the apparatus changes the first operating frequency to a second operating frequency which is different from the first operating frequency, and operates the first module at the second operating frequency. The apparatus reduces a total magnitude of electromagnetic waves caused by a simultaneous operation of two or more modules, thereby enhancing the quality of the mobile device and minimizing any undesirable impact upon the human body.

Description:
PRIORITY 
       [0001]    This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed on Aug. 22, 2011 in the Korean Intellectual Property Office and assigned Serial No. 10-2011-0083419, the entire disclosure of which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a method and an apparatus for reducing electromagnetic waves in a mobile device. More particularly, the present invention relates to preventing the magnitude of electromagnetic waves from exceeding a maximum when two or more modules are operating together in the mobile device. 
         [0004]    2. Description of the Related Art 
         [0005]    Nowadays, mobile devices such as mobile phones or portable terminals are widely used due to their convenience and portability. Normally, such a mobile device provides a great variety of functions such as a voice call, a video call, a short message service, a camera, a music player, a digital broadcasting service, an e-mail service, a location based service, and the like. In order to realize such functions, a mobile device has a plurality of modules. 
         [0006]    Each module of a mobile device produces electromagnetic waves while operating. Since electromagnetic waves have an undesirable impact upon the human body, mobile devices are regulated so as not to produce electromagnetic waves having a magnitude that exceeds a maximum level as established by industry standards. However, a mobile device is designed to suppress the occurrence of electromagnetic waves in excess of the standards in view of the activation of each module individually. Therefore, when two or more modules are operating at the same time, a mobile device may often produce electromagnetic waves in excess of the standards due to mixing or interference of different frequencies used in respective modules. For instance, when a camera module is used a charger module is operating, a mobile device of the related art may produce electromagnetic waves in excess of the standards. 
       SUMMARY OF THE INVENTION 
       [0007]    Aspects of the present invention 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 invention is to provide a method and an apparatus for reducing electromagnetic waves in a mobile device such that a magnitude of electromagnetic waves produced by the mobile device can be prevented from exceeding a maximum level as established by industry standards when two or more modules are operating simultaneously. 
         [0008]    According to an aspect of the present invention, a method for reducing electromagnetic waves in a mobile device that includes at least a first module and a second module having different functions is provided. The method includes operating the first module at a first operating frequency, when there is a request for operating the second module while the first module is operated, changing the first operating frequency to a second operating frequency which is different from the first operating frequency, and operating the first module at the second operating frequency. 
         [0009]    According to another aspect of the present invention, a method for reducing electromagnetic waves in a mobile device that includes at least a charger module and a camera module is provided. The method includes charging, by the charger module, a battery at a first charging frequency, determining whether a camera mode is activated during the charging of the battery, if the camera mode is activated, changing the first charging frequency to a second charging frequency which is different from the first charging frequency, and charging the battery at the second charging frequency. 
         [0010]    According to still another aspect of the present invention, an apparatus for reducing electromagnetic waves in a mobile device that includes at least a first module and a second module having different functions is provided. The apparatus includes a control unit for controlling the first module to change a first operating frequency of the first module to a second operating frequency that is different from the first operating frequency when there is a request for operating the second module while the first module is operated at the first operating frequency. 
         [0011]    Aspects of the present invention may reduce electromagnetic waves caused by a simultaneous operation of two or more modules, thereby enhancing the quality of a mobile device and also minimizing any undesirable impact upon the human body. 
         [0012]    Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
           [0014]      FIG. 1  is a block diagram illustrating the configuration of a mobile device in accordance with an exemplary embodiment of the present invention. 
           [0015]      FIG. 2  is a view illustrating a change of charging frequency in a charger module in accordance with an exemplary embodiment of the present invention. 
           [0016]      FIG. 3  is a flowchart illustrating a method for reducing electromagnetic waves in a mobile device in accordance with an exemplary embodiment of the present invention. 
           [0017]      FIG. 4  is a graph illustrating the results of measuring electromagnetic waves in a mobile device of the related art and in a mobile device in accordance with an exemplary embodiment of the present invention. 
       
    
    
       [0018]    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 OF EXEMPLARY EMBODIMENTS 
       [0019]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention 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 embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
         [0020]    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 invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents. 
         [0021]    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. 
         [0022]    A mobile device is a kind of electronic device that has a plurality of modules. A mobile device may be a mobile communication terminal, a Personal Digital Assistant (PDA), a smart phone, a tablet Personal Computer (PC), a Portable Multimedia Player (PMP), and the like. When two or more modules of the mobile device are operated at the same time, the mobile device may produce electromagnetic waves having a total magnitude that exceeds a maximum as established by industry standards due to mixing or interference of different operating frequencies used in the respective modules. In order to address the above problem, an exemplary mobile device of the present invention has features of preventing the occurrence of electromagnetic waves in excess of the standards by changing the operating frequency of the first module when the second module is operated during the operation of the first module. In an exemplary embodiment described below, a mobile communication terminal, a charger module, and a camera module will be used as examples of the mobile device, the first module, and the second module, respectively. However, it is to be understood that the mobile communication terminal, the charger module, and the camera module are used merely for example and not intended to limit application of the present invention. 
         [0023]      FIG. 1  is a block diagram illustrating the configuration of a mobile device in accordance with an exemplary embodiment of the present invention, and  FIG. 2  is a view illustrating a change of charging frequency in a charger module in accordance with an exemplary embodiment of the present invention. 
         [0024]    Referring to  FIGS. 1 and 2 , a mobile device  100  may include an interface unit  170 , a battery  160 , a camera module  150 , a charger module  140 , a display unit  130 , a memory unit  120 , and a control unit  110 . 
         [0025]    The display unit  130  displays information, including various menus of the mobile device  100 , input by a user or offered to a user. For instance, the display unit  130  may visually offer a variety of screen views in connection with the use of the mobile device  100 , such as an idle screen, a menu screen, a message writing screen, a call screen, and the like. More particularly, the display unit  130  may display a specific page that indicates a change of charging frequency of the charger module  140  when the camera module  150  is operated during a charging of the battery  160 . For instance, the display unit  130  may represent a predetermined graphical icon in the indicator area that usually shows the residual quantity of the battery  160 , the received signal strength, or the like. Alternatively, the display unit  130  may output a pop-up window for a given time (e.g., one second) to indicate a change of charging frequency of the charger module  140 . The display unit  130  may be formed of a Liquid Crystal Display (LCD), Organic Light Emitting Diodes (OLED), an Active Matrix OLED (AMOLED), or any other equivalent. If the display unit  130  is formed of a touch screen, the display unit  130  may also act as an input unit (not shown). 
         [0026]    The interface unit  170  allows a connection of an external device such as a Universal Serial Bus (USB) data cable, a USB charge cable, a travel adaptor, an earphone, or the like. More particularly, the interface unit  170  may be connected to a charging device (e.g., a USB charge cable, a travel adaptor, etc.) used for charging the battery  160 . 
         [0027]    The charger module  140  charges the battery  160 , using power supplied through a charging device connected to the interface unit  170 .In an exemplary implementation, the charger module  140  can change the charging frequency for charging of the battery  160 . More specifically, the charger module  140  charges the battery  160  at a first charging frequency in a normal state and, when the camera module  150  is operated during the battery charging, begins to charge the battery  160  at a second charging frequency. Namely, depending on whether the camera module  150  is operated, the charger module  140  suitably changes the charging frequency under the control of the control unit  110 . For instance, if the charger module  140  uses a Pulse Width Modulation (PWM) technique, the charger module  140  can change the charging frequency by modifying a pulse width as shown in  FIG. 2 . More specifically, the charger module  140  charges the battery  160  according to a pulse having a given width T in a normal state, and charges the battery  160  according to a pulse having an increased width T+α in response to use of the camera module  150 . Such modification of pulse width is, however, exemplary only and not to be considered as a limitation of the invention. In another exemplary embodiment, a pulse width may be decreased during use of the camera module  150 . 
         [0028]    The battery  160  produces an electric current to be supplied to elements of the mobile device  100 . Normally, the battery  160  is a secondary battery (i.e., a rechargeable battery) including a nickel battery, a cadmium battery, a Nickel Cadmium (NiCd) battery, a Nickel Metal Hydride (NiMH) battery, a Lithium ion (Li-ion) battery, a Lithium ion polymer (Li-ion polymer) battery, or any chemical cell. Since the battery  160  is understood by those skilled in the art, a detailed description will be omitted herein. In an exemplary embodiment of the invention, the battery  160  may be charged at the first charging frequency in a normal state and also be charged at the second charging frequency during use of the camera module  150 . 
         [0029]    The camera module  150  captures a still image or records a video. Normally, the camera module  150  may be operated at the operating frequency of 12 MHz˜48 MHz. This operating frequency may include a Main CLocK (MCLK) and a Peripheral CLocK (PCLK). The camera module  150  may include an image sensor and an image processor. The image sensor, such as a Complementary Metal Oxide Semiconductor (CMOS) image sensor or a Charge Coupled Device (CCD) image sensor, converts an optical image into an electric signal. The image processor performs a series of image processing tasks, such as resizing, Red Green Blue (RGB) signal transformation, Analog/Digital (A/D) conversion, noise reduction, digital zoom, rotation, encoding, and the like with respect to a signal input from the image sensor. Since the image sensor and the image processor are understood by those skilled in the art, a detailed description will be omitted herein. 
         [0030]    The memory unit  120  may store programs and data required for operations of the mobile device  100 , including an Operating System (OS) for the mobile device  100  and applications for executing various optional functions of the mobile device  100 , such as a sound reproduction, an image or video playback, and the like. More particularly, the memory unit  120  may store a specific application that changes, depending on whether the camera module  150  is operated, the charging frequency of the charger module  140 . 
         [0031]    The control unit  110  controls operations of the mobile device  100  and controls signal flows between internal blocks of the mobile device  100 . More particularly, the control unit  110  may suitably change the charging frequency of the charger module  140  in a charge mode, depending on whether the camera module  150  is operated. For this, the control unit  110  may determine whether the interface unit  170  is connected to any charging device (e.g., a USB charge cable, a travel adaptor, etc.). If a connection of a charging device is recognized, the control unit  110  may control the charger module  140  to charge the battery  160  at the first charging frequency (i.e., a default charging frequency). The control unit  110  may determine whether the camera module  150  is operated while the mobile device  100  is in a charge mode. If the camera module  150  is operated, the control unit  110  may transmit a control signal to the charger module  140  such that the charger module  140  changes the charging frequency to the second charging frequency. This is for preventing the occurrence of electromagnetic waves (e.g., radiated emission) in excess of the industry standards due to mixing or interference of the first charging frequency and the operating frequency of the camera module  150 . Namely, it is desirable that the second charging frequency does not cause a mixing or interference with the operating frequency of the camera module  150  or, if a mixing or interference is caused, that the second charging frequency is set to any frequency that does not cause electromagnetic waves more than the maximum established by the standards. When the camera module  150  is not operated, the control unit  110  may control the charger module  140  to again charge the battery  160  at the first charging frequency. Namely, in response to the non-operation of the camera module  150 , the control unit  110  may control the charger module  140  to restore the charging frequency from the second frequency to the first frequency. 
         [0032]    Although not illustrated in  FIG. 1 , the mobile device  100  of this invention may essentially or selectively include any other elements such as a radio frequency module, a short range communication module, a broadcast receiving module, a digital sound play module such as an MP3 module, an internet access module, and the like. According to a digital convergence tendency, such elements may be varied, modified and improved in various ways, and any other elements equivalent to the above elements may be additionally or alternatively equipped in the mobile device  100 . Meanwhile, as will be understood by those skilled in the art, some of the above-mentioned elements in the mobile device may be omitted or replaced with another. 
         [0033]      FIG. 3  is a flowchart illustrating a method for reducing electromagnetic waves in a mobile device in accordance with an exemplary embodiment of the present invention. 
         [0034]    Referring to  FIGS. 1 to 3 , the control unit  110  may be in an idle state at step  301 . The control unit  110  may determine whether a charge mode is activated at step  303 . The charge mode may be activated when the interface unit  170  is connected to any charging device (e.g., a USB charge cable, a travel adaptor, etc.). For this, the control unit  110  may have or be connected to General Purpose Input/Output (GPIO) terminals or interrupt terminals used to monitor a connection of a charging device. 
         [0035]    If it is determined at step  303  that the charge mode is not activated, the control unit  110  may perform any other selected function at step  305 . For instance, the control unit  110  may maintain the idle state or, in response to a user&#39;s request, perform a music play function, a video playback function, a call function, or the like. If it is determined at step  303  that the charge mode is activated, the control unit  110  may control the charger module  140  to charge the battery  160  at the first charging frequency, i.e., at a default charging frequency at step  307 . Namely, the control unit  110  may send, to the charger module  140 , a control signal that instructs the charger module  140  to charge the battery  160  at the first charging frequency. This control signal may be transmitted via an Inter-Integrated Circuit (I2C) bus, for example. 
         [0036]    Further, the control unit  110  may determine whether the camera module  150  is operated in the charge mode at step  309 . If it is determined at step  309  that the camera module  150  is not operated, the control unit  110  may perform step  319  to be described below. If it is determined at step  309  that the camera module  150  is operated, the control unit  110  may change the charging frequency of the charger module  140  to the second charging frequency at step  311 . As discussed above, it is desirable that the second charging frequency does not cause a mixing or interference with the operating frequency of the camera module  150  or, if a mixing or interference is caused, it is desirable that the second charging frequency is set to any frequency that does not cause electromagnetic waves to have a total magnitude in excess of the maximum as established by the industry standards. For instance, if the camera module  150  operates at 24 MHz, the second charging frequency may be set to 22 MHz or 26 MHz, which is exemplary only and not to be considered as a limitation of this invention. In most cases, the second charging frequency may be selected, through designer&#39;s experiments, as a specific frequency that causes the least electromagnetic waves when the camera module  150  and the charger module  140  are working simultaneously. 
         [0037]    After the charging frequency is changed at step  311 , the control unit  110  may control the charger module  140  to charge the battery  160  at the second charging frequency at step  313 . Thereafter, the control unit  110  may determine whether the camera mode is inactivated at step  315 . If it is determined at step  315  that the camera mode is not yet inactivated, the control unit  110  may maintain step  315 . When it is determined at step  315  that the camera mode is inactivated, the control unit  110  may control the charger module  140  to again charge the battery  160  at the first charging frequency at step  317 . Namely, in response to the non-operation of the camera module  150 , the control unit  110  may restore the charging frequency of the charger module  140  from the second frequency to the first frequency. 
         [0038]    Further, the control unit  110  may determine whether the charge mode is inactivated at step  319 . If it is determined at step  319  that the charge mode is not yet inactivated, the control unit  110  may return to step  309  and repeat the above process. When it is determined at step  319  that the charge mode is inactivated, the control unit  110  may stop the operation of the charger module  140  and enter into the idle state. 
         [0039]    Although in the-above discussed exemplary embodiment, the control unit  110  changes the charging frequency of the charger module  140  in response to the operation of the camera module  150  in the charge mode, the present invention is not so limited. Alternatively, the control unit  110  may temporarily stop the operation of the charger module  140  when the camera module  150  is operated in the charge mode. 
         [0040]      FIG. 4  is a graph illustrating the results of measuring electromagnetic waves in a mobile device of the related art and in a mobile device in accordance with an exemplary embodiment of the present invention. 
         [0041]    Referring to  FIGS. 1 to 4 , the first graph (a) shows the results of measuring electromagnetic waves (i.e., radiated emission) without changing the charging frequency of the charger module  140  as in a mobile device of the related art when the camera module  150  and the charger module  140  are in operation together. Further, the second graph (b) shows the results of measuring electromagnetic waves (i.e., radiated emission) after changing the charging frequency of the charger module  140  according to the above-discussed exemplary embodiment when the camera module  150  and the charger module  140  are in operation together. In these graphs (a) and (b), reference numeral  410  indicates the acceptable maximum of radiated emission according to industry standards. As shown in the first graph (a), a mobile device of the related art sometimes produces radiated emission in excess of the maximum. In contrast, as shown in the second graph (b), the mobile device  100  according to the above-discussed exemplary embodiment does not produce radiated emission in excess of the standards. 
         [0042]    It will be understood that the above-discussed exemplary method for reducing electromagnetic waves in a mobile device can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which are executed via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart block or blocks. These computer program instructions may also be stored in a computer usable or computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer usable or computer-readable memory produce an article of manufacture including instruction means that implement the function specified in the flowchart block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that are executed on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. And, each block of the flowchart illustrations may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative exemplary implementations, the functions noted in the blocks may occur out of order. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. 
         [0043]    Although the above-discussed embodiment of the present invention is the case where the camera module and the charger module are in operation together, this is exemplary only and not to be considered as a limitation of the invention. This invention may be effectively applied to any other cases in which at least any first and second modules are operated together and thus cause electromagnetic waves in excess of the industry standards. That is, if there is any request for operating a second module while a first module is operating at a first operating frequency, this invention may change the operating frequency of the first module so as not to cause electromagnetic waves in excess of the standards. 
         [0044]    While the invention has been shown and described with reference to certain exemplary 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 and their equivalents.