Abstract:
In a method for operating a power source of a mobile communication terminal, when a user selects a module, the mobile communication terminal allows the user to be informed in advance whether the corresponding function can be executed or not by comparing the total consumption current for operating the corresponding module with a supply of available current and notifies the user whether or not the selected module can be operated. By notifying the user in advance whether the selected module can be operated or not, the terminal can be prevented from being suddenly turned off and the power source can be effectively used.

Description:
[0001]     This Nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 2004-31892 filed in Korea on May 6, 2004, the entire contents of which are hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a mobile communication terminal, and more particularly, to a method for optimally operating battery power of mobile communication terminal.  
         [0004]     2. Description of the Background Art  
         [0005]     In general, a mobile communication service provider provides a user with functions related to communication functions including wireless Internet connections, text and multimedia messaging, wireless on-line gaming, and the like. Also, a mobile communication terminal manufacturer provides the user with functions that are performed by the terminal itself without being related to the communication functions, such as a phone-book, a memo, a schedule organizer, and the like.  
         [0006]     In order to use such functions, modules dedicated to perform the specified services are normally provided in the terminal. For example, the terminal may include an RF module for performing wireless communications services, a camera module for capturing images, an LCD module for outputting images and characters, and so on. The terminal may also include a wireless LAN, FM Radio, Bluetooth, and the like.  
         [0007]     With multiple functions being provided, multiple modules are typically mounted within the terminal requiring a complicated construction. Also, the amount of power, and more specifically electrical current, consumed by the terminal increases as more functions are added.  
         [0008]     An example of a module that consumes a large amount of current in a mobile communication terminal (hereinafter called a “Terminal”) is a color display unit. The color display unit may consume three times more power than a black and white display unit.  
         [0009]     In general, different modules consume different amounts currents. As power is consumed by the modules, the voltage of a battery supplying the current correspondingly drops. When the battery voltage drops below a certain level due to power consumption by the modules, power is usually turned off to prevent the modules from malfunctioning and/or from being damaged.  
         [0010]      FIG. 1  is a block diagram illustrating a related art apparatus for operating a power source of a mobile communication terminal.  
         [0011]     As shown in  FIG. 1 , the related art apparatus includes an application circuit  10 , a voltage control unit  20 , a main circuit  30 , and a battery  40 .  
         [0012]     The application circuit  10  includes at least one module, for example, an RF module  11 , FM Radio  12 , a wireless LAN  13 , a camera module  14 , a Bluetooth module  15  and an LCD module  16  to provide services to the user.  
         [0013]     The voltage control unit  20  includes a plurality of low drop output regulators (LDOs)  21 - 26  connected to each of the modules in the application circuit  10 . Each LDO is connected to the battery  40  and maintains a voltage level appropriate to the correspondingly connected module. The maintenance of the voltage level of the LDOs is under the control of the main circuit  30 .  
         [0014]     The main circuit  30  includes an A/D converter  31  for converting the voltage level of the battery  40  into a digital signal, a control unit  32  for controlling each LDO, a memory  33 , a keypad  34 , and an audio unit  35 . The control unit  32  controls each LDO based on the voltage level of the battery  40  as indicated by the digital signal output by the A/D converter  31 .  
         [0015]     An operation of the related art apparatus will be described as follows.  
         [0016]     As shown in  FIG. 1 , the power (current) necessary for operating each module of the application circuit  10  is supplied from the battery  40  through the corresponding LDO. Constant voltage and constant current are normally necessary to operate each module. For example, the RF module may require 200 mA of current nominally at 3.2 V for operation. If the battery  40  is drained, the needed constant voltage and constant current cannot be maintained.  
         [0017]     The related art apparatus turns off the terminal if the battery voltage level drops below a certain level—the cutoff voltage. For example, the voltage level of the battery  40  can be checked periodically through the A/D converter  31  as shown in  FIG. 2 . If the voltage of the battery  40  drops below the cut off level, 3.2 V for example, the control unit  32  in the main circuit  30  unconditionally turns off the terminal to prevent malfunctions and/or damages.  
         [0018]     However, if the terminal is unconditionally turned off as described above, the following problems can occur.  
         [0019]     When the user selects a specific module through the keypad  34 , i.e. when the user selects a specific function, the control unit  32  unconditionally turns on the selected module by outputting a module enable signal. If the selected module consumes a small amount of current, little to no problem may occur since the voltage drop may be insignificant and thus still may be within the tolerance of the selected module. However, if the selected module consumes a significant amount of current, the corresponding battery voltage drop may be significant and thus be outside of the tolerance of the selected module. This problem is generated because the voltage drop of the battery caused by the selected module is not accounted for in the related art apparatus.  
         [0020]     For example, the user may intend to make a call and/or listen to the radio when the battery voltage has dropped to at or near the cut off level. Indeed, it may be that the terminal has been automatically turned off. When the radio, which consumes a small amount of current is selected, a small voltage drop occurs and the radio may be operated. On the other hand, when the RF module, which consumes a large amount of current is selected, a large voltage drop occurs, perhaps to below the cut off voltage.  
       SUMMARY OF THE INVENTION  
       [0021]     Therefore, an object of the present invention is to provide a method for operating a power source of a mobile communication terminal capable of optimally using battery power.  
         [0022]     Another object of the present invention is to provide a method for operating a power source of a mobile communication terminal enabling to operate a specific module by predicting voltage sag of the battery caused by each module.  
         [0023]     To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, a method for operating a power source of a mobile communication terminal, includes checking a total consumption current for operating a selected module when the user selects the selected module; checking supply of available current of a battery; and notifying the user whether or not the selected module can be operated, based on a comparison of the current consumed by the selected module and the available current of the battery.  
         [0024]     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.  
         [0026]     In the drawings:  
         [0027]      FIG. 1  is a block diagram illustrating an apparatus for operating a power source of a mobile communication terminal in accordance with the background art;  
         [0028]      FIG. 2  is a diagram illustrating a cut off voltage of a battery in accordance with the background art; and  
         [0029]      FIG. 3  is a flowchart illustrating an apparatus for operating a power source of a mobile communication terminal in accordance with an embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.  
         [0031]     An aspect of the present invention is to determine whether to turn on or turn off a selected module by comparing an amount of current which can be supplied from battery with an amount of current consumed by each module.  
         [0032]     An apparatus for operating a power source in a mobile communication terminal in accordance with an embodiment of the present invention may also be described with reference to  FIG. 1 . However, the embodiment also includes the memory  33  and the data stored therein.  
         [0033]     As shown in Table 1 and Table 2, a supply of available current, i.e., the amount of current that is capable of being supplied by the battery for each battery voltage level and the amount of current consumed for each module may be stored in the memory  33  in a table form. In Table 1, the voltage level listed in the first column are all assumed to be above the cut off voltage. In this example, the cut off voltage is assumed to be 3.2 volts.  
                                           TABLE 1                           Supply of available current for each battery voltage level                    Supply of available           Battery voltage (V)   Current (mA)                            4   1000           3.9   800           3.8   700           3.7   600           3.6   500           3.5   300           3.4   100           3.3   50                      
 
         [0034]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                   
               
               
                 Consumption current for each type of module 
               
             
          
           
               
                   
                 Module 
                 Current consumed (mA) 
               
               
                   
                   
               
             
          
           
               
                   
                 Main circuit 
                 30 
               
               
                   
                 R/F module 
                 200 
               
               
                   
                 Wireless LAN 
                 160 
               
               
                   
                 Camera module 
                 150 
               
               
                   
                 Blue tooth 
                 100 
               
               
                   
                 LCD module 
                 60 
               
               
                   
                 FM radio 
                 50 
               
               
                   
                 Sub LCD 
                 1 
               
               
                   
                   
               
             
          
         
       
     
         [0035]     When a module is selected to be operated, the control unit  32  may compare the current values stored in Table 1 and Table 2. If the selected module consumes less current than supply of available current from the battery, then the control unit  32  may enable the selected module to be operated. If the selected module consumes more current than the available supply, the control unit  32  may inform the user that the corresponding module cannot be operated.  
         [0036]     Note that other module or modules may already be operating and thus already consuming a certain amount of current. The control unit  32  may take this into account. In other words, the control unit  32  may calculate the actual supply of available current as being a difference of the supply of current capable of being supplied at a particular voltage level of the battery (from Table 1) and the current required by the selected module (from Table 2). For example, the main circuit may always be operating and thus 30 mA of current may always be consumed.  
         [0037]     Hereinafter, with reference to  FIG. 3 , a method for operating a power source of the mobile communication terminal in accordance with an embodiment of the present invention will be described in detail.  
         [0038]     When the user selects a specific operation of the terminal through the keypad  34 , the control unit  32  may select a module for performing the corresponding operation (S 100 ). The control unit  32  may determine the current required for operating the selected module by reading consumption current for each module from Table 2 from the memory  33  (S 110 ). In addition, the control unit  32  may detect the voltage level of the battery  40 , for example based on the output value from the A/D converter  31 . The control unit  32  may then determine the supply of available current, i.e. the amount of current capable of being supplied, corresponding to the detected battery voltage level from Table 1 (S 120 ).  
         [0039]     The control unit  32  may check whether the total consumption current of all modules presently operating plus the amount of current required by the selected module exceeds the supply of available current of the battery  40  (S 130 ). If the total consumption current exceeds the supply of available current from the battery  40 , the control unit  32  may then inform the user that the selected module cannot be operated (S 140 ). If the total consumption current does not exceed the supply current of the battery  40 , the control unit  32  may turn on the selected module, for example by outputting an enable signal through the corresponding LDO (S 150 ).  
         [0040]     As an illustration, assume that the main circuit  30  is is always operated and that the battery voltage is 3.4V. In such a circumstance, the supply of available current of the battery  40  is 100 mA. If the user selects the wireless LAN  13 , then the total current required is 190 mA [main circuit (30 mA)+wireless LAN (160 mA)], which exceeds the available current.  
         [0041]     Accordingly, when the user intends to use the wireless LAN  13 , the control unit  32  informs the user, visually on a display unit (LCD) or by auditory means such as a speaker, that the wireless LAN  13  cannot be used. At this point, the user may turn off one or more of the presently operating modules so that the specific module may be operated. The user may be provided with an ordered list of presently operating modules so that the user may easily choose. The ordered list may be based on a priority that is predetermined. The predetermined priority may be set as a factory default that is changeable by the user.  
         [0042]     On the other hand, if the user intends to use the FM Radio  12 , the total amount of current required is 80 mA [main circuit (30 mA)+FM Radio (50 mA)]. Under this circumstance, the control unit  32  may immediately operate the FM Radio.  
         [0043]     It may be that at step S 140 , i.e. when the total required current of the selected module and the presently operating modules exceed the supply of available current of the battery  40 , the control unit  32  may automatically turn off one or more presently operating modules and then display a message instructing the user to use the currently selected module (S 140 ). In such a case, the modules currently being operated may be sequentially turned off based on a priority as described above.  
         [0044]     For example, assume that the battery voltage is 3.5 V. Then the supply of available current of the battery  40  is 300 mA. Also assume that in addition to the main circuit  30 , the Bluetooth module  15  is presently being utilized and the user receives a telephone call. If the user elects to answer the call, the total amount of current required becomes 330 mA [main circuit (30 mA)+Bluetooth (100 mA)+RF module (200 mA)].  
         [0045]     Accordingly, the total amount of required current (330 mA) to operate the Bluetooth  15  and the RF module  11  exceeds the supply of available current (300 mA) from the battery  40 . Under this circumstance, the control unit  32  may disable the Bluetooth module  15  and display a message instructing the user to use the telephone. The Bluetooth module  15  may be of lower priority than the main circuit  30 .  
         [0046]     As described thus far, the embodiment present invention allows an effective use of battery power by optimally operating modules through comparison of required consumption current for each type of module with the supply of available current. The embodiment of the present invention also enables the battery life to be extended.  
         [0047]     As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.