Abstract:
A drive control device that is capable of ensuring user convenience. The drive control device ( 100 ) is a device that controls the drive of an electronic device driven by means of the power of a battery, and comprises a battery information management section ( 280 ) and a battery state assessment section ( 300 ). Said battery information management section ( 280 ) manages the remaining power of a rechargeable battery, replaceable battery or other type of reserve battery for the electronic device, and/or whether a reserve battery exists. On the basis of the remaining power of the reserve battery and/or whether a reserve battery exists, said battery state assessment section ( 300 ) determines whether to drive the electronic device in a power-saving mode when the remaining power of a battery mounted in the electronic device has decreased to no more than a preset battery capacity.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a drive control apparatus, a drive control method, and a drive control program that control the driving of an electronic device driven with the power of a battery. 
       BACKGROUND ART 
       [0002]    In recent years, various electronic devices driven by the power of batteries, such as a smartphone, a tablet, and a portable game console (hereinafter, simply referred to as an “electronic device”), have been introduced. Related arts for controlling the driving of electronic devices includes an art that controls whether to drive an electronic device in a normal mode or a power saving mode (for example, see Patent Literature (hereinafter, referred to as PTL) 1). 
         [0003]    In the art described in PTL 1, when the remaining power level of the battery of a mobile terminal becomes equal to or less than a predetermined level, the time required for moving to a place where the battery can be charged and/or replaced (hereinafter referred to as an “power supply location”) is calculated, and the calculated time is compared with the drivable time in the normal mode. Then, the related art switches the driving mode of the mobile terminal from the normal mode to the power saving mode according to the result of comparison. That is, the related art determines whether additional power can be acquired when the remaining power level of the battery becomes equal to or less than the predetermined level. When determining that the additional power can be acquired, the related art determines to maintain the normal mode in the driving mode of the mobile terminal. On the other hand, when determining that the additional power cannot be acquired, the related art determines to switch the driving mode of the mobile terminal from the normal mode to the power saving mode. The power saving mode is a driving mode that allows the device to be driven while saving power compared with the normal mode although some of the functions available in the normal mode are not available in the power saving mode. 
         [0004]    According to the related art, when the moving route and velocity are fixed, it is possible to strike a balance between maintaining the normal mode and maintaining the drivable time, which in turn, improves the convenience of users. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         PTL 1 
         Japanese Patent Application Laid-Open No. 2008-135920 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    However, the moving route and velocity of a mobile terminal are rarely fixed. In fact, the related art may be unable to appropriately determine the necessity of switching to the power saving mode. That is, the related art may be unable to avoid running out of battery that could have been avoided by switching to the power saving mode sooner, or may unnecessarily restrict functions due to unnecessary switching to the power saving mode. That is, the related art has a problem in that it is difficult to secure the convenience of users. 
         [0008]    It is an object of the present invention to provide a drive control apparatus, a drive control method, and a drive control program that can secure the convenience of users. 
       Solution to Problem 
       [0009]    A drive control apparatus according to an aspect of the present invention is an apparatus that controls driving of an electronic device driven by power of a battery, the apparatus including: a battery information management section that manages at least one of a remaining power level of a reserve battery including a charging battery or a replacement battery for the electronic device, and the presence or absence of the reserve battery; and a battery state determination section that determines whether or not to drive the electronic device in a power saving mode when the remaining power level of the battery loaded in the electronic device decreases to a level equal to or less than a predetermined battery capacity, based on at least one of the remaining power level of the reserve battery and the presence or absence of the reserve battery. 
         [0010]    A drive control method according to an aspect of the present invention is a method of controlling driving of an electronic device driven by power of a battery, the method including: managing at least one of a remaining power level of a reserve battery including a charging battery or a replacement battery for the electronic device, and the presence or absence of the reserve battery; and determining whether or not to drive the electronic device in a power saving mode when the remaining power level of the battery loaded in the electronic device decreases to a level equal to or less than a predetermined battery capacity, based on at least one of the remaining power level of the reserve battery and the presence or absence of the reserve battery. 
         [0011]    A drive control program according to an aspect of the present invention is a program stored on a non-transitory computer readable medium that controls driving of an electronic device driven by power of a battery, the program causing a computer of the electronic device to execute processing including: managing at least one of a remaining power level of a reserve battery including a charging battery or a replacement battery for the electronic device, and the presence or absence of the reserve battery; and determining whether or not to drive the electronic device in a power saving mode when the remaining power level of the battery loaded in the electronic device decreases to a level equal to or less than a predetermined battery capacity, based on at least one of the remaining power level of the reserve battery and the presence or absence of the reserve battery. 
       Advantageous Effects of Invention 
       [0012]    The present invention determines to switch to the power saving mode, taking into account a reserve battery, and can therefore improve the convenience of users. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]      FIG. 1  is a block diagram illustrating the configuration of a drive control apparatus according to Embodiment 1 of the present invention; 
           [0014]      FIG. 2  is a block diagram illustrating the configuration of an electronic device including the drive control apparatus according to Embodiment 2 of the present invention; 
           [0015]      FIG. 3  is a drawing for explaining the meaning of flags in Embodiment 2 of the present invention; 
           [0016]      FIG. 4  is a flow chart illustrating an example of operations of the electronic device according to Embodiment 2 of the present invention; 
           [0017]      FIG. 5  is a block diagram illustrating a first example of another configuration of the electronic device according to Embodiment 2 of the present invention; 
           [0018]      FIG. 6  is a block diagram illustrating a second example of another configuration of the electronic device according to Embodiment 2 of the present invention; 
           [0019]      FIG. 7  is a block diagram illustrating a third example of another configuration of the electronic device according to Embodiment 2 of the present invention; 
           [0020]      FIG. 8  is a block diagram illustrating a fourth example of another configuration of the electronic device according to Embodiment 2 of the present invention; and 
           [0021]      FIG. 9  is a flow chart illustrating an example of operations of the electronic device according to Embodiment 2 of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0022]    Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings. 
       Embodiment 1 
       [0023]    Embodiment 1 of the present invention is an example of a basic mode of the present invention. 
         [0024]      FIG. 1  is a block diagram illustrating the configuration of a drive control apparatus according to the present embodiment. 
         [0025]    In  FIG. 1 , drive control apparatus  100  is an apparatus that controls the driving of an electronic device driven by the power of a battery. Drive control apparatus  100  includes battery information management section  280  and battery state determination section  300 . 
         [0026]    Battery information management section  280  manages the remaining power level of a reserve battery including a battery used for charging (hereinafter, referred to as “charging battery”) or a battery used for replacement (hereinafter, referred to as “replacement battery”) for an electronic device, and/or the presence or absence of the reserve battery. 
         [0027]    In this description, the term “remaining power level of a reserve battery” is based on a concept including both the remaining power level of a reserve battery that is obviously connectable to the electronic device immediately, and the remaining power level of a reserve battery that may not be connectable to the electronic device immediately. 
         [0028]    In addition, the term “presence or absence of a reserve battery” is based on a concept including whether or not the user of the electronic device carries around a reserve battery with him or her, whether or not the user holds a reserve battery, and whether or not a reserve battery connectable to the electronic device immediately is present. Moreover, the term “presence or absence of a reserve battery” is based on a concept including whether or not it is likely that a reserve battery connectable to the electronic device immediately is present. 
         [0029]    That is, the term “remaining power level of a reserve battery and/or the presence or absence of a reserve battery” is based on a concept including whether or not the power of a reserve battery can be used and whether or not it is likely that the power of a reserve battery is usable. 
         [0030]    When the remaining power level of the battery loaded in the electronic device decreases to a level equal to or less than predetermined battery capacity, battery state determination section  300  determines whether to drive the electronic device in the power saving mode. Additionally, battery state determination section  300  determines whether to drive the electronic device in the power saving mode, on the basis of the remaining power level of the reserve battery and/or the presence or absence of the reserve battery, which are managed by battery information management section  280 . 
         [0031]    Drive control apparatus  100  includes, for example, a CPU (central processing unit), a storage media such as a ROM (read only memory) storing a control program, and a working memory such as a RAM (random access memory), which are not illustrated. In this case, the function of each component described above is implemented by the CPU executing the control program. 
         [0032]    Drive control apparatus  100  as described above can switch whether to drive the electronic device in the power saving mode when the remaining power level of the battery decreases to a level equal to or less than the predetermined battery capacity. More specifically, drive control apparatus  100  can switch whether to drive the electronic device in the power saving mode according to the remaining power level of the reserve battery or the presence or absence of the reserve battery. Thereby, drive control apparatus  100  can maintain the normal mode when the power of the reserve battery can be used, and can switch to the power saving mode when the power of the reserve battery cannot be used. That is, even when the moving route or velocity of the electronic device is not fixed, drive control apparatus  100  can determine the necessity of appropriately switching to the power saving mode, and can improve the convenience of users. 
         [0033]    Battery information management section  280  may also estimate whether the user holds the charged reserve battery. In this case, battery state determination section  300  determines whether to drive the electronic device in the power saving mode, on the basis of the above estimation result, when the remaining power level of the battery mounted in the electronic device decreases to a level equal to or less than the predetermined battery capacity. Drive control apparatus  100  can include a battery state linkage control section that controls the driving of the electronic device according to the result of determination of battery state determination section  300 . 
       Embodiment 2 
       [0034]    Embodiment 2 according to the present invention is an example in which the present invention is applied to an electronic device capable of acquiring position information, and is a specific example for performing the determination about an additional reserve battery. The electronic device is, for example, a smartphone. 
         [0035]    The configuration of the electronic device including a driving apparatus according to the present embodiment will be described first. 
         [0036]      FIG. 2  is a block diagram illustrating the configuration of the electronic device including the drive control apparatus according to the present embodiment. 
         [0037]    In  FIG. 2 , electronic device  200  includes display section  210 , display control section  220 , communication section  230 , communication control section  240 , battery  250 , remaining battery level calculation section  260 , position information acquisition section  270 , battery information management section  280 , remaining battery level threshold setting section  290 , battery state determination section  300 , and battery state linkage control section  310 . 
         [0038]    Display section  210  is an apparatus section that displays an image, and is, for example, an LCD (Liquid Crystal Display). 
         [0039]    Display control section  220  drives display section  210  by the power supplied from battery  250 . Display control section  220  appropriately shifts the driving mode of display section  210  from the normal mode to the power saving mode in response to a control from battery state linkage control section  310  described below. Display control section  220  causes, for example, the brightness of display section  210  in the power saving mode to be lower than that in the normal mode. Display control section  220  also displays a message for prompting replacing of the battery or charging of the charging battery as a warning to the user about the remaining battery level, when a battery residue warning flag is “1.” 
         [0040]    Communication section  230  is an apparatus section that performs radio communication, and is a WiFi (Registered trademark) communication circuit, for example. 
         [0041]    Communication control section  240  drives communication section  230  by the power supplied from battery  250 . Communication control section  240  appropriately shifts the driving mode of communication section  230  from the normal mode to the power saving mode in response to a control from battery state linkage control section  310  described below. In the power saving mode, communication control section  240 , for example, sets the transmission speed of communication control section  240  to be lower than that in the normal mode. 
         [0042]    Battery  250  is a battery pack (battery) loaded in electronic device  200 , stores power for driving electronic device  200 , and supplies the stored power to electronic device  200 . Battery  250  is generally loaded detachably from electronic device  200 , and is replaceable with a replacement reserve battery (battery for replacement) (not illustrated), for example. Battery  250  is connectable to charging apparatus  410  from the outside of electronic device  200 . Charging apparatus  410  is an additional reserve battery (battery for charging), and charges battery  250  when being connected to battery  250  (when being added). When battery  250  is not detachably loaded in electronic device  200 , the replacement reserve battery is not used, but charging apparatus  410  is used. 
         [0043]    Charging apparatus  410  is, for example, a primary or secondary battery such as a mobile charger, a battery charger, a mobile battery or a charging battery. 
         [0044]    Battery  250  supplies power to components of electronic device  200  (including components not illustrated) including display control section  220  and communication control section  240 . However, the drawings and description of the power supply system are omitted. The power saving mode is not limited to display control section  220  or communication control section  240 , and is applied also to the power supply system, which is not illustrated. 
         [0045]    Remaining battery level calculation section  260  immediately detects that the remaining power level (hereinafter referred to as “remaining battery level” as appropriate) of battery  250  decreases to a level equal to or less than predetermined battery capacity. More specifically, remaining battery level calculation section  260  detects the remaining battery level successively (for example, periodically, i.e., every unit time). Remaining battery level calculation section  260  then outputs the detection result to battery information management section  280  and battery state determination section  300 . 
         [0046]    Position information acquisition section  270  acquires information the position of electronic device  200  (hereinafter referred to as “position information”) using, for example, GPS (Global Positioning System) or a radio network. Position information acquisition section  270  then outputs the acquired position information to battery information management section  280 . 
         [0047]    Battery information management section  280  estimates whether the user of electronic device  200  holds charged charging apparatus  410 . Battery information management section  280  also estimates whether electronic device  200  is located outdoors, on the basis of the position information. Furthermore, battery information management section  280  estimates whether battery  250  is being charged on the basis of the detection result of remaining power level or the connection state to a charger through an interface, such as Micro USB. 
         [0048]    Then, when estimating that electronic device  200  is located outdoors, battery information management section  280  determines that electronic device  200  cannot immediately be connected to a system power supply (for example, an AC power supply, not illustrated). Then, battery information management section  280  estimates that the user holds charged charging apparatus  410  under condition that battery  250  is charged even in a state where battery  250  cannot be charged from the system power supply. Then, when estimating that the user holds charged charging apparatus  410 , battery information management section  280  reports the estimation to battery state determination section  300 . 
         [0049]    Battery information management section  280  includes charging apparatus interface (IF)  281 . When charging apparatus  410  is connected to battery  250 , charging apparatus interface  281  acquires information on the remaining amount of power stored in charging apparatus  410 . This can simplify the process to find out the battery capacity of charging apparatus  410 . Charging apparatus interface  281  is, for example, a Micro USB (Universal Serial Bus) interface utilized in a smartphone or the like. Battery information management section  280  successively reports information on the remaining amount of power stored in charging apparatus  410  as well to battery state determination section  300 . Moreover, when charging apparatus  401  is connected, charging apparatus interface  281  may be configured to acquire information to distinguish whether connected charging apparatus  410  is charging apparatus  410  including a reserve battery or a system power supply. This can simplify estimation of whether the user holds charged charging apparatus  410 . 
         [0050]    Remaining battery level threshold setting section  290  stores a predetermined threshold concerning the remaining battery level. This threshold is a remaining battery level used as a timing reference to determine whether to shift the driving mode of electronic device  200  from the normal mode to the power saving mode. 
         [0051]    When the remaining battery level decreases, battery state determination section  300  determines whether to drive electronic device  200  in the power saving mode, on the basis of the estimation result of battery information management section  280 . More specifically, when estimating that the user holds charged charging apparatus  410 , battery state determination section  300  determines to drive electronic device  200  in the normal mode when the remaining battery level decreases. On the other hand, when not estimating that the user holds charged charging apparatus  410 , battery state determination section  300  determines to drive electronic device  200  in the power saving mode when the remaining battery level decreases. 
         [0052]    That is, when battery information management section  280  determines that the user holds charged charging apparatus  410 , battery state determination section  300  determines whether to shift the driving mode to the power saving mode. More specifically, battery state determination section  300  determines whether to shift the driving mode to the power saving mode in consideration of the total residual capacity including not only the remaining battery level of battery  250  but also the stored amount of power of charging apparatus  410 . In Embodiment 1, it is assumed that charging apparatus  410  is fully charged. 
         [0053]    Battery state determination section  300  outputs the determination result of whether the driving mode of electronic device  200  is maintained as the normal mode or is shifted to the power saving mode to battery state linkage control section  310 . 
         [0054]    Battery state determination section  300  compares the remaining battery level with the threshold set in remaining battery level threshold setting section  290  (hereinafter, simply referred to as a “threshold”), and considers a case where the remaining battery level becomes equal to or less than the threshold as the above-described case where the remaining battery level decreases. That is, when the remaining battery level decreases to a level equal to or less than the predetermined battery capacity, battery state determination section  300  determines whether to drive electronic device  200  in the power saving mode, on the basis of the estimation result of battery information management section  280 . 
         [0055]    Battery state linkage control section  310  controls the driving of electronic device  200  according to the determination result of battery state determination section  300 . More specifically, battery state linkage control section  310  determines whether predetermined conditions are satisfied. Then, when determining that the predetermined conditions are satisfied, battery state linkage control section  310  shifts the driving of electronic device  200  (including display control section  220  and communication control section  240 ) from the normal mode to the power saving mode. The predetermined condition is a condition that electronic device  200  is determined to be driven in the power saving mode when the remaining battery level decreases to a level equal to or less than the predetermined battery capacity and that it is detected that the remaining battery level decreases to a level equal to or less than the predetermined battery capacity. 
         [0056]    Electronic device  200  includes, for example, a CPU, a storage medium such as a ROM storing a control program, and a working memory such as a RAM, which are not illustrated. In this case, the function of each component described above is implemented by the CPU executing the control program. 
         [0057]    Such electronic device  200  can switch whether or not to drive electronic device  200  in the power saving mode when the remaining power level of the battery decreases to a level equal to or less than the predetermined battery capacity, according to whether the user holds charged charging apparatus  410 . Accordingly, when the remaining power level of the battery decreases and when the power of charging apparatus  410  can be used, electronic device  200  can maintain the normal mode. Then, when the remaining power level of the battery decreases and when the power of charging apparatus  410  cannot be used, electronic device  200  can switch from the normal mode to the power saving mode. That is, even when the moving route or velocity of the electronic device is not fixed, electronic device  200  can appropriately determine the necessity of switching to the power saving mode, which makes it possible to improve the convenience of users. 
         [0058]    The description of the configuration of electronic device  200  has been given thus far. 
         [0059]    Next, operations of electronic device  200  will be described. Before this description, flags used in these operations will be described first. 
         [0060]    Electronic device  200  manages information on whether the user holds the charged reserve battery (charging apparatus  410  in the present embodiment), using a flag representing the presence or absence of the reserve battery (hereinafter referred to as a “reserve battery flag”). The value of the reserve battery flag is “0,” the reserve battery flag represents that it is estimated that the user does not hold the charged reserve battery. On the other hand, when the value of the reserve battery flag is “1,” the reserve battery flag represents that it is estimated that the user holds the charged reserve battery. 
         [0061]      FIG. 3  is a drawing for explaining the meaning of the flags used by electronic device  200 . 
         [0062]    As illustrated in  FIG. 3 , first state pattern  511  includes the reserve battery flag “0” and the threshold&lt;the remaining battery level (larger than the threshold) and indicates the absence of the charged reserve battery and a high remaining battery level. Therefore, a preferred driving mode in this state pattern is the normal mode. 
         [0063]    Second state pattern  512  includes the reserve battery flag “1” and the threshold&lt;the remaining battery level (larger than the threshold) and indicates the presence of the charged reserve battery and a high remaining battery level. Therefore, a preferred driving mode in this state pattern is the normal mode. 
         [0064]    Third state pattern  513  includes the reserve battery flag “0” and the threshold≦the remaining battery level (equal to or less than the threshold) and indicates the absence of the charged reserve battery and a low remaining battery level. In this case, while the remaining battery level decreases and approaches zero, additional power is unlikely acquired. Therefore, the preferred driving mode in this state pattern is the power saving mode. 
         [0065]    On the other hand, fourth state pattern  514  includes the reserve battery flag “1” and the threshold≦the remaining battery level (equal to or less than the threshold) and indicates the presence of the charged reserve battery and a low remaining battery level. In this case, although the remaining battery level decreases and approaches zero, additional power is likely acquired by connection to charging apparatus  410  by the user. Application of the power saving mode in this case causes unnecessary functional limitation and thus deteriorate the convenience of the user. Therefore, the preferred driving mode in this state pattern is the normal mode. 
         [0066]    The preferred driving mode in this case is a driving mode that operates under the assumption that charging apparatus  410  is charged and the reserve battery stores sufficient power. As illustrated in the flow chart described below, when charging apparatus  410  is not charged and when the reserve battery stores sufficient power does not store sufficient power, the preferred driving mode becomes the power saving mode. 
         [0067]    Battery information management section  280  manages the flags and sets their values on the basis of the detection result of the remaining battery level and determination of whether battery  250  is charged outdoors. Battery state determination section  300  can also refer to the values of the flags managed by battery information management section  280 . 
         [0068]    Electronic device  200  uses a flag indicating the presence or absence of a need to warn the user of for the remaining battery level (hereinafter referred to as a “battery residue warning flag”), and issues the warning. The battery residue warning flag is a flag set to “1” when a warning message is displayed which prompts charging by charging apparatus  410  or the system power supply to the user in the case of a low remaining battery level. 
         [0069]      FIG. 4  is a flow chart illustrating an example of operations of electronic device  200 . 
         [0070]    In this chart, an assumption is made that electronic device  200  has already completed the estimation, at the start point, of whether the user holds charged charging apparatus  410 , on the basis of the daily usage of electronic device  200 . More specifically, battery information management section  280  detects that a condition that electronic device  200  is being charged and is located outdoors is satisfied. This condition represents that charging is performed outdoors, where it is difficult to connect to a system power supply, and that it is likely that the user holds charged charging apparatus  410 . Whether the charging is performed can be determined on the basis of whether the remaining battery level increases, or the connection state of the IF such as Micro USB with charging apparatuses  410 . 
         [0071]    It is assumed that charging apparatus  410  held by the user is fully charged at the start point, that battery  250  has a large remaining amount i.e., the reserve battery flag is equal to 1, and that the driving mode of electronic device  200  is the normal mode. 
         [0072]    In Step S 1010 , battery state determination section  300  determines whether to satisfy a predetermined condition (battery state check condition) for performing a determination about the remaining battery level. This condition is, for example, the start timing of electronic device  200  or the arrival of predetermined periodical timings. Battery state determination section  300  proceeds to Step S 1170  described below if the predetermined condition is not satisfied (S 1010 : NO). On the other hand, battery state determination section  300  proceeds to Step S 1030  if the predetermined condition is satisfied (S 1010 : YES). 
         [0073]    In Step S 1030 , battery information management section  280  determines whether to satisfy a condition that the charging is being performed. Battery information management section  280  proceeds to Step S 1040  when this condition is satisfied (S 1030 : YES). Battery information management section  280  proceeds to Step S 1060  described below when the condition is not satisfied (S 1030 : NO). 
         [0074]    In Step S 1040 , battery information management section  280  determines whether the battery residue warning flag is set to “1.” Battery information management section  280  proceeds to Step S 1050  when the battery residue warning flag is set to “1” (S 1040 : YES). On the other hand, battery information management section  280  proceeds to Step S 1080  described below when the battery residue warning flag is not set to “1” (S 1040 : NO). 
         [0075]    In Step S 1050 , battery information management section  280  deletes the warning message displayed on display section  210  in Steps S 1100  and S 1150  described below, sets the battery residue warning flag to “0,” and proceeds to Step S 1080  described below. 
         [0076]    In Step S 1060 , battery information management section  280  determines whether to satisfy a condition that outdoor charging is completed. This determination is made in order to determine whether charging apparatus  410  is spent, i.e., whether the reserve battery flag should be set to “0.” Battery information management section  280  proceeds to Step S 1070  when this condition is satisfied (S 1060 : YES). On the other hand, battery information management section  280  proceeds to Step S 1080  described below when the condition is not satisfied (S 1060 : NO). 
         [0077]    In Step S 1070 , battery information management section  280  sets the reserve battery flag to “0.” 
         [0078]    Then, in Step S 1080 , battery state determination section  300  performs a reserve battery determination. That is, battery state determination section  300  determines whether the reserve battery flag has a value of “0.” That is, this determination is to determine whether the state of electronic device  200  can be determined to be first state pattern  511  or third state pattern  513  explained in  FIG. 3 . Battery state determination section  300  proceeds to Step S 1090  when the reserve battery flag has a value of “1” (S 1080 : NO). On the other hand, battery state determination section  300  proceeds to Step S 1120  described below when the reserve battery flag has a value of “0” (S 1080 : YES). 
         [0079]    That is, electronic device  200  checks whether the process of Step S 1080  estimates that the user holds charged charging apparatus  410 . 
         [0080]    In Step S 1090 , battery state determination section  300  performs a warning determination. That is, battery state determination section  300  determines whether or not the remaining battery level (the remaining amount of power of battery  250 ) is equal to or less than the threshold. Battery state determination section  300  proceeds to Step S 1170  described below when the remaining battery level is not equal to or less than the threshold. (S 1090 : NO). On the other hand, battery state determination section  300  proceeds to Step S 1100  when the remaining battery level is equal to or less than threshold (S 1090 : YES). 
         [0081]    In Step S 1100 , for example, battery state determination section  300  displays a message on display section  210  and reports to the user that battery  250  has a low remaining amount. That is, while the remaining battery level approaches zero, battery state determination section  300  battery calls attention to charging by the additional reserve battery. Then, battery state determination section  300  sets the battery residue warning flag to “1” and proceeds to Step  1170  described below. 
         [0082]    That is, electronic device  200  performs operations in the case of the presence of charged charging apparatus  410  through the processes of Steps S 1090  and S 1100 . 
         [0083]    Note that, when the remaining battery level is equal to or less than a second threshold that is smaller than the threshold described above, battery state determination section  300  may switch the driving mode of the electronic device to the power saving mode although the reserve battery can be used. Additionally, when the remaining battery level of battery  250  becomes equal to or less than the threshold described above or the second threshold, for example, it is preferable that battery state determination section  300  should display a message for issuing a warning to the user, using display section  210 . 
         [0084]    On the other hand, in Step S 1120 , battery information management section  280  performs a power saving mode determination. That is, battery information management section  280  calculates the total remaining battery level including charging apparatus  410  (i.e., the remaining amount of power of battery  250 +the remaining amount of power of charging apparatus  410 ) and determines whether or not this total remaining battery level is equal to or less than the threshold. That is, this determination is a determination to distinguish between first state pattern  511  and third state pattern  513  explained in  FIG. 3  in the state of electronic device  200 . Battery information management section  280  proceeds to Step S 1170  described below when the total remaining battery level is not equal to or less than the threshold. (S 1120 : NO). On the other hand, battery state determination section  300  proceeds to Step S 1130  when the total remaining battery level is equal to or less than threshold (S 1120 : YES). 
         [0085]    In Step S 1130 , battery state determination section  300  shifts the driving mode of electronic device  200  to the power saving mode. 
         [0086]    Then, in Step S 1150 , for example, battery state determination section  300  displays a message on display section  210  and prompt the user to charge the battery by a system power supply or the like or to replace battery  250 . Battery state determination section  300  also sets the battery residue warning flag to “1.” 
         [0087]    That is, electronic device  200  performs operations in the case of the absence of charged charging apparatus  410  through the processes of Steps S 1120  to S 1150 . 
         [0088]    In Step S 1170 , battery state determination section  300  determines whether the termination of the process is instructed by a user operation or the like. Battery state determination section  300  returns to Step S 1010  when the termination of the process is not instructed (S 1170 : NO). Battery state determination section  300  terminates a series of the processes if the termination of the process is instructed (S 1170 : YES). 
         [0089]    By the above operations, electronic device  200  can switch whether to drive electronic device  200  in the power saving mode when the remaining power level of the battery decreases, depending on whether the user holds charging apparatus  410 . Electronic device  200  can also prompt the user to replace or charge the battery at an appropriate timing. Electronic device  200  can determine switching to the power saving mode in consideration of not only the remaining amount of power of loaded battery  250  but also the remaining amount of power of charging apparatus  410  held by the user. 
         [0090]    As described above, electronic device  200  including the drive control apparatus according to the present embodiment switches whether to operate electronic device  200  in the power saving mode when the remaining power level of battery  250  decreases to a level equal to or less than the predetermined battery capacity. More specifically, electronic device  200  including the drive control apparatus according to the present embodiment switches whether to operate electronic device  200  in the power saving mode depending on whether the user holds charged charging apparatus  410  (battery for charging). In this manner, electronic device  200  can maintain the normal mode when the power of charging apparatus  410  can be used, and can switch to the power saving mode when the power of charging apparatus  410  cannot be used. That is, even when the moving route or velocity of the device is not fixed, electronic device  200  can appropriately determine the necessity of switching to the power saving mode, and can improve the convenience of the user. 
         [0091]    Additionally, the configuration of electronic device  200  including drive control apparatus  100  according to the present embodiment is not limited to the configuration illustrated in  FIG. 2 . 
         [0092]      FIG. 5  is a block diagram illustrating a first example of another configuration of electronic device  200  according to the present embodiment, and corresponds to  FIG. 2 . The same components as those in  FIG. 2  are assigned the same reference numerals, and the descriptions thereof will be omitted. 
         [0093]    As illustrated in  FIG. 5 , electronic device  200  may include, for example, reserve battery residual capacity setting section  320 . Reserve battery residual capacity setting section  320  is an apparatus section that receives, from the user, setting of the residual capacity of charging apparatus  410  held by the user. In this case, battery information management section  280  acquires information on the remaining power level of the reserve battery from the user input. Thereby, battery information management section  280  can omit the process for detecting the remaining amount of power of loaded charging apparatus  410 . 
         [0094]      FIG. 6  is a block diagram illustrating a second example of another configuration of electronic device  200  according to the present embodiment, and corresponds to  FIG. 2 . The same components as those in  FIG. 2  are assigned the same reference numerals, and the descriptions thereof will be omitted. 
         [0095]    As illustrated in  FIG. 6 , electronic device  200  may include, for example, time management section  330  and apparatus-use-state acquisition section  340 . Time management section  330  is an apparatus that generates and outputs time information obtained by time measurement. Apparatus-use-state acquisition section  340  is an apparatus section that generates and outputs execution application information representing an application executed by electronic device  200 . In this case, battery information management section  280  calculates, for example, the difference between the power consumption for every application not during the charging and the power consumption for the execution time of the application utilized during the charging. Then, battery information management section  280  determines the power amount charged from charging apparatus  410  based on the calculated difference. 
         [0096]      FIG. 7  is a block diagram illustrating a third example of another configuration of electronic device  200  according to the present embodiment, and corresponds to  FIG. 2 . The same components as those in  FIG. 2  are assigned the same reference numerals, and the descriptions thereof will be omitted. 
         [0097]    As illustrated in  FIG. 7 , electronic device  200  may be configured to acquire, for example the remaining amount (residual capacity) of power of the reserve battery, which is stored in residual capacity storing section  411 , from residual capacity storing section  411  provided in reserve battery (charging apparatus  410 ). In this case, electronic device  200  acquires the remaining amount of power of the reserve battery connected to electronic device  200 , for example, through charging apparatus interface  281 . In this case, battery information management section  280  acquires information on the remaining power level of the reserve battery directly from the reserve battery. Thus, battery information management section  280  can omit the process for calculating the remaining amount of power of charging apparatus  410 . 
         [0098]    Additionally, it is preferable that the determination or acquisition of the remaining amount of power of the reserve battery should be performed at the determination timing for the total remaining battery level described above. 
         [0099]    Electronic device  200  may also cause battery information management section  280  to detect the power amount charged from charging apparatus  410  and may calculate the remaining amount of power of charging apparatus  410  on the basis of the difference between the detected power amount and the initial stored amount of power of charging apparatus  410 . The initial stored amount of power of the reserve battery is preset by, for example, the user. 
         [0100]    Electronic device  200  may be configured to cause reserve battery residual capacity setting section  320  to receive, from the user, setting of the presence or absence of charged charging apparatus  410 . 
         [0101]    When the capacity of charging apparatus  410  is larger than the capacity of the battery loaded in electronic device  200 , the battery loaded in electronic device  200  can fully be charged a plurality of times. When such charging apparatus  410  is connected to electronic device  200 , battery information management section  280  may acquire information representing how many times the battery loaded in electronic device  200  can be charged fully, as information on the remaining power level of the reserve battery. Battery information management section  280  may also calculate how many times the battery can fully be charged on the basis of the remaining amount of power of charging apparatus  410  and the capacity of the battery loaded in electronic device  200 . 
         [0102]    In this case, battery information management section  280  may set the battery residue warning flag to “1” when the battery cannot fully be charged once more. That is, battery information management section  280  may determine to output a message that prompts the user to charge the charging battery, on condition that the remaining power level of the managed charging battery becomes equal to or less than a remaining power level necessary for one time of full charging, at least. 
         [0103]    Electronic device  200  may be configured to cause battery information management section  280  to estimate that the reserve battery is also charged fully when battery  250  is fully charged by the system power supply without charging apparatus  410  being loaded. That is, when battery  250  loaded in electronic device  200  is charged with a system power supply in a house or the like, charging apparatus  410  may be estimated to be also charged simultaneously. In such a case, electronic device  200  may also cause battery information management section  280  to set the value of the reserve battery flag to “1,” assuming that the charged reserve battery is secured. 
         [0104]    In the present embodiment, an example is described in which the additional reserve battery is connected to electronic device  200  through the micro USB interface. However, the connection system for the additional reserve battery is not limited to this example. The additional reserve battery includes a charging battery connected through a wired connection system such as USB, or a non-contact system such as Qi. 
         [0105]    The technique for acquiring the information on the remaining amount of power stored in the additional reserve battery is not limited to the user input or USB communication. 
         [0106]      FIG. 8  is a block diagram illustrating a fourth example of another configuration of electronic device  200  according to the present embodiment, and corresponds to  FIG. 2 . The same components as those in  FIG. 2  are assigned the same reference numerals, and the descriptions thereof will be omitted. 
         [0107]    As illustrated in  FIG. 8 , the additional reserve battery (charging apparatus  410 ) includes, for example, secondary battery  412 , remaining battery level monitoring section  413  and data communication section  414 . Secondary battery  412  stores power. Remaining battery level monitoring section  413  monitors the remaining amount of power stored in secondary battery  412 . Data communication section  414  acquires information on the remaining amount of power stored in secondary battery  412 , from remaining battery level monitoring section  413 . Then, data communication section  414  transmits the acquired information through radio communication such as an IC (Integrated Circuit) tag, and Bluetooth (Registered trademark). 
         [0108]    On the other hand, charging apparatus interface  281  of electronic device  200  includes a radio communication antenna (not illustrated) adapted to the IC tag of data communication section  414 , and receives the information transmitted from data communication section  414 . 
         [0109]    In this way, battery information management section  280  may acquire the information on the remaining amount of power stored in the additional reserve battery, through radio communication. Battery information management section  280  may be configured to report the information on the remaining amount of the power, at a timing of pushing a report button provided in charging apparatus  410 . 
         [0110]    The acquisition source for the information on the remaining amount of power stored the additional reserve battery does not need to be the additional reserve battery itself. For example, when a battery charger for charging the additional reserve battery stores information on the remaining power level of the additional reserve battery, battery information management section  280  may directly acquire this information from the battery charger. 
         [0111]    When the information on the remaining power level that is stored in the additional reserve battery cannot directly be acquired from the additional reserve battery or the battery charger, battery information management section  280  may also receive the information input from the user. Alternatively, battery information management section  280  may estimate the remaining amount of power stored in the additional reserve battery, instead of receiving the information input from the user. Accordingly, battery state determination section  300  can more surely make the determination about the power saving mode described above. 
         [0112]    Battery information management section  280  may also manage information on the remaining amount of the power for each of a plurality of charging apparatuses  410  on the basis of an ID assigned to each charging apparatus  410 . 
       Embodiment 3 
       [0113]    The embodiment of the present invention is an example of the determination about a replacement reserve battery. 
         [0114]    The configuration of the electronic device including the drive control apparatus according to the present embodiment is the same as that of Embodiment 2, and is therefore not illustrated. 
         [0115]    However, in electronic device  200  in the present embodiment, charging apparatus  410  is not additionally connected to battery  250 , but is loaded in electronic device  200  instead of battery  250  as a replacement. 
         [0116]    Battery information management section  280  also acquires a history of replacement of battery  250 , and estimates whether the user holds a replacement reserve battery on the basis of the acquired history. 
         [0117]    More specifically, battery information management section  280  monitors whether the remaining battery level varies drastically. Then, when the remaining battery level increases drastically, battery information management section  280  determines that battery  250  is replaced with a charged reserve battery. On the other hand, when the remaining battery level decreases drastically, battery information management section  280  determines that the battery is replaced in order to charge the reserve battery. 
         [0118]    That is, battery information management section  280  can determine whether a battery pack currently loaded as battery  250  is a previously used as a default battery or a reserve battery to be used later, on the basis of the transition of the remaining battery level. 
         [0119]    Note that, electronic device  200  needs to be surely powered off for battery replacement. Therefore, it is preferable that whether the remaining battery level varies drastically should be determined on the basis of the comparison before and after power-off. In this case, battery information management section  280  needs to store the last value of the remaining battery level detected before power-off and time information indicating the time of detection. 
         [0120]    When the information is stored in this way, battery information management section  280  holds the value of the remaining battery level of the removed battery. Therefore, battery information management section  280  can sum the held value of the remaining battery level and the value of the remaining battery level of the battery determined to have been newly loaded, and can thereby calculate the total remaining battery level (corresponding to the total remaining battery level in Embodiment 2) readily. 
         [0121]      FIG. 9  is a flow chart illustrating an example of operations of electronic device  200  according to the present embodiment, and corresponds to  FIG. 4  of Embodiment 2. The same steps as those in  FIG. 4  are assigned the same step numbers, and the descriptions thereof will be omitted. 
         [0122]    In Step S 1031   a,  battery information management section  280  calculates the difference between the remaining battery level detected this time and the remaining battery level detected last time (hereinafter referred to as “remaining amount difference”). Battery information management section  280  then determines whether to satisfy a condition that the calculated remaining amount difference is larger than predetermined remaining amount threshold 1 and that the difference in the time of the detection between the last time and this time (hereinafter referred to as “time difference”) is smaller than a predetermined time threshold. When this condition is not satisfied (S 1031   a:  NO), battery information management section  280  proceeds to Step S 1061   a.  On the other hand, when this condition is satisfied (S 1031   a:  YES), battery information management section  280  proceeds to Step S 1051   a.    
         [0123]    In Step S 1051   a,  battery information management section  280  sets the value of the reserve battery flag to “0.” 
         [0124]    That is, when the remaining battery level increases rapidly, battery information management section  280  determines that the replacement of battery  250  having a small remaining amount with a charged reserve battery is detected, and sets the value of the reserve battery flag to “0.” 
         [0125]    In Step S 1061   a,  battery information management section  280  determines whether to satisfy a condition that the remaining amount difference is equal to or less than predetermined remaining amount threshold 2 and that the time difference is smaller than the predetermined time threshold. When this condition is not satisfied (S 1061   a:  NO), battery information management section  280  proceeds to Step S 1080   a.  On the other hand, when this condition is satisfied (S 1061   a:  YES), battery information management section  280  proceeds to Step S 1071   a.    
         [0126]    In Step S 1071   a,  battery information management section  280  sets the value of the reserve battery flag to “1.” 
         [0127]    That is, when the remaining battery level decreases drastically, battery information management section  280  acquires information indicating the decrease as a use history of the reserve battery. Then, when detecting that the charged battery is removed and replaced with another battery having a small remaining amount, battery information management section  280  estimates that the user holds the charged battery as a reserve battery, and sets the value of the reserve battery flag to “1.” When detecting that the loaded battery that is charged fully or almost fully is replaced with another battery having a small remaining amount, battery information management section  280  may recognize that the removed battery is a reserve battery. 
         [0128]    Then, in the present embodiment, when the total remaining battery level is equal to or less than the threshold (S 1120 : YES), the processing shifts to the driving mode to the power saving mode at Step S 1130  and then proceeds to Step S 1151   a.    
         [0129]    In Step S 1151   a,  battery state determination section  300  displays a message that calls attention to the charging from the system power supply as a warning message on display section  210 . 
         [0130]    In Step S 1090 , when the remaining battery level is equal to or less than the threshold (S 1090 : YES), the process proceeds to Step  1101   a.    
         [0131]    In Step S 1101   a,  battery state determination section  300  displays a message that raises caution for replacing with the held reserve battery for replacement, or charging from the system power supply, as a warning message on display section  210 . 
         [0132]    The warning messages displayed in S 1101   a  and S 1151   a  disappear on display section  210  when electronic device  200  is powered off for the replacement with the replacement reserve battery. Then, after electronic device  200  is powered on to start up after the replacement of the battery, the warning message is not displayed since the remaining battery level is larger than the threshold. 
         [0133]    In this way, electronic device  200  according to the present embodiment can acquire the history of replacement of battery  250  loaded in electronic device  200  from the transition of the remaining battery level. Then, electronic device  200  can estimate whether the user holds the reserve battery for replacement and whether the currently loaded battery is a default battery or a reserve battery, on the basis of the acquired history. 
         [0134]    Thereby, when a plurality of batteries are replaced for the usage, electronic device  200  can consider the usage sequence after charging and can estimate the remaining amount of power of an unused reserve battery. That is, even when the reserve battery is for replacement, electronic device  200  can appropriately determine the necessity of switching to the power saving mode, and can improve the usability of the user. 
         [0135]    Embodiment 2 and Embodiment 3 have been described using an example in which battery information management section  280  holds the estimation result of whether the user holds the reserve battery, as a reserve battery flag, but are not limited to this. For example, the estimation result may be held in the battery state determination section  300  or battery state linkage control section  310 . 
         [0136]    Battery information management section  280  may also determine whether the charging is performed indoors or outdoors, and may store a predetermined area including a place where indoor charging is performed more frequently as a place where charging from the system power supply is performed. If no user operation continues for a predetermined time period or more in the stored place, battery state determination section  300  may estimate that both the battery and the reserve battery are charged fully, at the time of the next user operation. 
         [0137]    Each battery loaded in electronic device  200  may report information representing whether the battery is a reserve battery or a regular (default) battery, to electronic device  200 . In this case, electronic device  200  does not need to estimate whether the user holds the reserve battery for replacement, and can make a determination on the basis of the report from the battery to simplify the process. 
         [0138]    Alternatively, assuming that the reserve battery stores predetermined power, battery information management section  280  may manage only the presence or absence of the reserve battery. Then, battery state determination section  300  may determine whether to perform the power saving mode, only on the basis of the presence or absence of the reserve battery. In this case, electronic device  200  can determine to shift the driving mode to the power saving mode, taking into account the reserve battery, while reducing the processing load and power consumption. 
         [0139]    The disclosure of Japanese Patent Application No. 2011-287710, filed on Dec. 28, 2011, including the specification, drawings and abstract, is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0140]    The present invention is useful for a drive control apparatus, a drive control method, and a drive control program that can secure the convenience of users. In particular, the present invention is suitable for various mobile devices such as a smartphone, a tablet terminal, and a mobile game console that are provided with an additional or replacement reserve battery. In addition to the mobile devices, the present invention is also useful in various electronic devices such as a power-assisted bicycle that may be provided with an additional or replacement reserve battery. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           100  Drive control apparatus 
           200  Electronic device 
           210  Display section 
           220  Display control section 
           230  Communication section 
           240  Communication control section 
           250  Battery 
           260  Remaining battery level calculation section 
           270  Position information acquisition section 
           280  Battery information management section 
           281  Charging apparatus interface 
           290  Remaining battery level threshold setting section 
           300  Battery state determination section 
           310  Battery state linkage control section 
           320  Reserve battery residual capacity setting section 
           410  Charging apparatus 
           411  Residual capacity storing section 
           412  Secondary battery 
           413  Remaining battery level monitoring section 
           414  Data communication section