Abstract:
The present invention relates to a charging technique used in a battery, a charging device, and an information-processing system. According to the present invention, for charging a secondary cell of a battery, charging the secondary cell is controlled based on identifying information output from the battery.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates generally to secondary battery cells, and more specifically to systems and methods for charging secondary battery cells.  
         [0003]     2. Description of the Related Art  
         [0004]     Generally, image capture systems, typified by digital cameras and video cameras, derive power from removable secondary cells.  
         [0005]     Conventional systems for charging such secondary cells are well known. In one method, the secondary cell is charged separately from the image capture system. That is, the secondary cell is removed from the image capture system and attached to a separate charger to charge the secondary cell. In another method, the secondary cell is charged without removal from the image capture system. Here, the charging circuit and the image capture system are integrated so that the secondary cell can be charged within the image capture system.  
         [0006]     Accordingly, the secondary cell to be charged and the charger/charging circuit should be compatible particularly when the secondary cell and the charger are integrated. That is, the charger/charging circuits are designed to use a valid battery (includes secondary cell and a computer) type. Charging a secondary cell different from a valid battery type can result in malfunction of the charger/charging circuit or a decrease in life of the secondary cell. This is indicated in, for example, Japanese Patent Laid-Open No. 8-182206. Another related art system is disclosed in Japanese Patent Laid-Open No. 2001-135360.  
         [0007]     In particular, if the charging circuit malfunctions, the user must leave the image capture system (e.g., digital camera or video camera), in a service center for repair. Hence, the user is deprived of beneficial use and enjoyment of the image capture system while repairs are undertaken.  
         [0008]      FIG. 5  shows a related art system for recording and reproducing an image. This system is driven by a battery  518  having a secondary cell  514  and a battery microcomputer  515  serving to identify a valid battery. The battery microcomputer  515  derives power only from the secondary cell  514 . To charge the system, a system-controlling unit  508  first communicates with the battery microcomputer  515  to determine whether the battery  518  is valid. If so, a switching circuit  513  enables a charging circuit  512  to supply power to the secondary cell  514 . Otherwise, power supply to the secondary cell  514  is disabled to prevent failure.  
         [0009]     In such related art systems, the secondary cell  514  supplies power to the battery microcomputer  515 . If there is insufficient power in the secondary cell  514 , the battery microcomputer  515  cannot be driven, and the user cannot successfully charge the secondary cell  514  even if the battery  518  is valid.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention aims to solve the above problems. An advantage of the present invention is that a battery, a charging device, and an image capture system are provided that can reliably identify a valid battery and continue charging operations even when an associated secondary cell has insufficient power.  
         [0011]     According to an aspect of the present invention, a battery for driving a predetermined system includes a secondary cell for storing electric charge, a supply terminal for supplying power from the secondary cell to the predetermined system, a charge terminal for receiving power from a charging circuit of the predetermined system and charging the secondary cell, an electronic circuit for outputting predetermined identifying information to the predetermined system, a receive terminal for receiving power required for operating the electronic circuit from the predetermined system at least when the amount of charge in the secondary cell is insufficient to drive the electronic circuit, and a transmission terminal for transmitting to the predetermined system the identifying information output from the electronic circuit after the electronic circuit receives power from the receive terminal.  
         [0012]     According to another aspect of the present invention, a battery for driving an image capture circuit is provided. The battery includes a secondary cell that stores electric charges to supply power to the image capture circuit. The battery also includes a charge terminal that receives power from a charging circuit of the image capture system to charge the secondary cell. The battery further includes a controller circuit that receives power from the image capture circuit to operate the controller circuit, and the controller circuit outputs identifying information about the battery to the image capture circuit. The identifying information functions to authenticate the battery to determine whether it is valid. Thus, upon receipt of power from the image capture circuit, the controller outputs the identifying information to authenticate the battery as valid. After authentication, the charge terminal receives power from the charging circuit of the image capture system to charge the secondary cell.  
         [0013]     Further features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a block diagram of a typical system for recording and reproducing an image according to an embodiment of the present invention.  
         [0015]      FIG. 2  is a flowchart for a charging method according to a first embodiment.  
         [0016]      FIG. 3  is a flowchart for a charging method according to a second embodiment.  
         [0017]      FIG. 4  is a flowchart for a charging method according to a third embodiment.  
         [0018]      FIG. 5  illustrates a related art image capture system capable of charging a secondary battery cell. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0019]     The embodiments will be described with reference to the drawings.  
       First Embodiment  
       [0020]      FIG. 1  is a block diagram of a typical system for recording and reproducing an image according to this embodiment of the present invention. A system-controlling unit  108  is a microcomputer for coordinating and executing instructions to control the entire system. An image-capturing unit  101  is a converting circuit that converts images of objects received through a lens system  100  into video signals. An image signal processing unit  102  is a circuit that performs predetermined image processing on the video signals. A display-controlling unit  103  performs display control when a signal subjected to image processing is displayed on an image-displaying unit  104 . A compression and decompression unit  105  is a circuit that compresses a signal output from the image signal processing unit  102  and decompresses image data read out from a memory card  107 . A memory card interface  106  is a circuit that controls reading from and writing to the memory card  107 . Switches  109  include a playback switch, an image-forward switch, an image-back switch, an image-displaying key, a setting key, and a readout key.  
         [0021]     A commercial power supply  116  supplies power to the system via an AC adapter (not shown). A constant voltage generating circuit  111  converts the voltage supplied from the commercial power supply (AC power supply)  116  to a voltage suitable for use in each unit. A charging circuit  112  controls power to be supplied to a battery  118 . A second switching circuit  113  is used for enabling or disabling power supply to the battery  118  (that is, for switching supply or not supplying power to the battery  118 ). A secondary cell  114  stores power supplied from the system. A battery microcomputer  115  authenticates the battery  118  to the system to ensure the battery  118  is valid. A first switching circuit  117  enables or disables power supply from the constant voltage generating circuit  111  to the battery microcomputer  115  (that is, switches supplying or not supplying power to the battery microcomputer  115 ). Valid batteries are those that meet certain criteria and are determined to be compatible with the corresponding charger/charging circuit (e.g., batteries are genuine batteries or equivalent batteries which operate in the same way as the genuine batteries).  
         [0022]     The battery  118  uses the secondary cell  114  to supply power to the system. Although not shown, the battery  118  includes a charge terminal for receiving power from the charging circuit  112  via the second switching circuit  113  to charge the secondary cell  114 , a receive terminal for receiving power required for operating the battery microcomputer  115 , and a communication terminal for communicating with the system-controlling unit  108 .  
         [0023]     Similarly, the system includes a charge terminal for supplying the secondary cell  114  with power provided from the charging circuit  112 , a receive terminal for receiving power from the secondary cell  114 , a power-supplying terminal for supplying power to the battery microcomputer  115 , and a communication terminal for carrying out communication between the battery microcomputer  115  and the system-controlling unit  108 .  
         [0024]     Some of these terminals may be combined, physically. For example, in the battery, the charge terminal and the supply terminal may be combined; in the system, the charge terminal and the receive terminal may be combined. These terminals may be contact terminals or non-contact terminals, such as antennas or electromotive coils.  
         [0025]      FIG. 2  illustrates a method for charging a secondary cell in accordance with an embodiment of the present invention. Specifically, in  FIG. 2 , the method for charging the battery  118  of  FIG. 1  is described.  
         [0026]     In step S 201 , the system determines if the main switch (not shown) of the switches  109  is in the OFF position. If so, the system shifts to a charging mode for charging the secondary cell  114 , and the process proceeds to step S 202 .  
         [0027]     In step S 202 , the constant voltage generating circuit  111  determines whether the system is connected to the AC power supply  116  via the AC adapter. If connection is established, the processing moves to step S 203 . If connection is not established, the processing goes back to step S 201 .  
         [0028]     In step S 203 , the constant voltage generating circuit  111  starts supplying power to the system-controlling unit  108  of the system.  
         [0029]     In step S 204 , the system-controlling unit  108  determines whether the battery  118  is connected to the system. This determination can be made by providing, for example, a switch for recognizing the connection on a face where the battery is in contact with the system. If the battery  118  is connected to the system, the processing moves to step S 205 . If not, the processing moves back to step S 203 .  
         [0030]     In step S 205 , the system-controlling unit  108  transmits a control signal (ON signal) to the first switching circuit  117 . Upon receipt of the ON signal, the first switching circuit  117  switches an internal switch so as to start supplying power to the battery microcomputer  115 .  
         [0031]     In step S 206 , the battery microcomputer  115  is started up and the battery microcomputer  115  then transmits a notification signal to notify the system-controlling unit  108  of the start up.  
         [0032]     In step S 207 , the system-controlling unit  108  performs battery authentication between the battery microcomputer  115  and the system-controlling unit  108 . For example, the system-controlling unit  108  receives a battery ID from the battery microcomputer  115  and determines whether the received ID represents a valid battery. In addition, the system-controlling unit  108  may check whether data transmitted from the battery microcomputer  115  on voltage, current, temperature, or the like of the secondary cell  114  matches data of valid batteries. Thus, valid batteries are those that meet certain criteria and are determined to be compatible with the corresponding charger/charging circuit. When the authentication determines that the battery  118  is a valid battery, the processing moves to step S 208 . If the battery  118  is not a valid battery, the processing moves to step S 212  to terminate the charging process.  
         [0033]     In step S 208 , the system-controlling unit  108  transmits a control signal (ON signal) to the second switching circuit  113 . Upon receipt of the ON signal, the second switching circuit  113  switches an internal switch so as to supply power to the secondary cell  114 .  
         [0034]     In step S 209 , the charging circuit  112  starts charging the secondary cell  114 .  
         [0035]     In step S 210 , the charging circuit  112  determines whether the secondary cell  114  is fully charged. If so, the charging circuit  112  transmits a signal indicating full charge to the system-controlling unit  108 , and the processing moves to step S 211 . If not, charging continues.  
         [0036]     In step S 211 , upon receipt of the full charge signal, the system-controlling unit  108  transmits an OFF signal to the second switching circuit  113 . When the second switching circuit  113  receives the OFF signal, the processing moves to step S 212 . The second switching circuit  113  switches the internal switch so as to cut off power from the charging circuit  112 . In this manner, a system is provided for charging a secondary cell without the associated disadvantages of the related art.  
         [0037]     As described above, according to this embodiment, an electronic circuit, such as the battery microcomputer  115 , serving to determine whether a battery is a valid battery derives power directly from a charging device. As a result, even when the amount of charge in the secondary cell  114  is insufficient or the battery microcomputer  115  derives power only from an external device, the electronic circuit of the battery can be advantageously driven as soon as the electronic circuit is attached to the charging device.  
         [0038]     Additionally, exchange of data indicating whether the battery is a valid battery between the electronic circuit, such as the battery microcomputer  115 , and the charging device (e.g., the system-controlling unit  108 ) facilitates the determination. This reduces failure, such as a breakdown in a charging device and battery degradation, associated with charging an invalid battery.  
       Second Embodiment  
       [0039]     In a second embodiment, power is not supplied to the battery microcomputer  115  during charging so that wasteful power consumption is reduced.  
         [0040]      FIG. 3  is a flowchart for a charging method according to the second embodiment. In  FIG. 3 , the same processes as in  FIG. 2  are labeled with the same reference numerals, and explanation thereof is omitted.  
         [0041]     In step S 207 , which is described above, if it is determined that the battery  118  is a valid battery, the processing moves to step S 308 ; if not, the processing moves to step S 318 .  
         [0042]     In steps S 308  and S 318 , the system-controlling unit  108  finishes communication with the battery microcomputer  115 .  
         [0043]     In steps S 309  and S 319 , the system-controlling unit  108  transmits a control signal (OFF signal) to the first switching circuit  117 . Upon receipt of the OFF signal, the first switching circuit  117  switches the internal switch so as to stop supplying power to the battery microcomputer  115 . After step S 309  and step S 319 , the processing moves to step S 208  and step S 212 , respectively, both of which are explained above.  
         [0044]     As described above, according to the second embodiment, in addition to the advantages of the first embodiment, wasteful power consumption is reduced since power is not supplied to the battery microcomputer  115  during charging.  
       Third Embodiment  
       [0045]     In a third embodiment, for an invalid battery, a charge target setting indicating a fully charged condition is made smaller than that for a valid battery so that the danger of failures occurring when an invalid secondary cell is connected is reduced.  
         [0046]      FIG. 4  is a flowchart for a charging method according to the third embodiment. In  FIG. 4 , the same processes as in  FIG. 2  are labeled with the same reference numerals, and explanation thereof is omitted.  
         [0047]     In step S 207 , when it is determined that the battery  118  is not a valid battery, the processing moves to step S 400 . In step S 400 , the system-controlling unit  108  makes a target setting for full charge smaller than that for a valid battery. The changed setting is set in the charging circuit  112 . After completing the change of the target setting, the processing moves to step S 208 .  
         [0048]     Note that in the second embodiment, step S 400  may be inserted right after step S 319 .  
         [0049]     As described above, according to the third embodiment, for an invalid battery, a charge target setting indicating a fully charged condition is made smaller than that for a valid battery so that the danger of failures occurring when an invalid secondary cell is connected is reduced.  
         [0050]     While the present invention has been described with reference to what are presently considered to be the embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.  
         [0051]     This application claims priority from Japanese Patent Application No. 2003-410771 filed Dec. 9, 2003, which is hereby incorporated by reference herein.