Abstract:
The present invention provides an electrical apparatus, program and method for a user to display a preliminary charging state in a battery. In one aspect, the present invention provides an electrical apparatus that is capable of receiving a battery for supplying electric power to a main unit by discharging after charging, comprising preliminary charge judging means for judging whether or not the battery is in a preliminary charging state that is a recovery from over-discharge, and display means for displaying an indication of preliminary charging if the preliminary charge judging means judges that the battery is in the preliminary charging state.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical apparatus having a battery usable by repeating the charge and discharge function, and more particularly to an electrical apparatus in relation to a preliminary charging state. 
     2. Description of Related Art 
     For an information terminal equipment device, often represented by a notebook type personal computer (hereinafter referred to as a notebook PC), or various kinds of electrical apparatus such as a PDA (Personal Digital Assistant), an MD (Mini Disc) device, and/or a video camera, electric power is typically supplied directly from the commercial power supply, or from a rechargeable battery (battery, storage battery, secondary battery) that can be used many times over by simply repeating the charging and discharging of the battery. Such a battery, by way of example, may include a nickel hydride battery or a nickel cadmium battery (NiCd battery) that has relatively large capacity, and which is also typically inexpensive. In a further example, a lithium ion battery (having a higher energy density per unit weight than the nickel cadmium battery) and a lithium polymer battery, using the solid polymer without liquid electrolyte, are provided. 
     For this chargeable and dischargeable battery, an intelligent battery having a CPU inside a battery pack that is mounted on the electrical apparatus is widely employed. This intelligent battery may conform with the SBS (Smart Battery System), and communicate with a controller on the main unit side, employing an SBS protocol. 
     As is known, these batteries store electricity by the use of the chemical reaction, but involve a reversible range and an irreversible range as a result of the chemical reaction involved in the process of charging and discharging. If the discharge is made to a predetermined extent, the battery is restored to an originally charged state by supplying electricity from the outside. However, if the battery is discharged beyond a full discharge (discharge up to 100% of the rated capacity of battery), the battery becomes a so-called over-discharge to consume an electromotive force produced by a reaction other than the intrinsically reversible chemical reaction, resulting in an abnormally charged state even by charging. 
     In recovering the over-discharged battery, it is typically required to make the preliminary charge (trickle charge, pre-charge) of charging the battery at a low current before a quick charge so as not to damage the battery. If a fixed voltage value is reached in this preliminary charge, the quick charge is effected to make ordinary charge. This preliminary charge may be needed for about two hours depending on the extent of over-discharge of the battery. 
     However, in a conventional system, the preliminary charge and the quick charge are similarly handled. For even if a predetermined power supply meter displays that the charging is running, the user does not know that the preliminary charge is being performed. At such a time, an indication of a capacity of 0% is often displayed continuously during the two hours of preliminary charging, usually in a display. In such a case, the user may unknowingly exchange the normal battery by mistakenly assuming that a malfunction of not charging the battery has occurred. Furthermore, concerns also arise that as a result of the unobvious activity, a user may be inclined to make what actually is an otherwise unnecessary inquiry to a help center. 
     Moreover, in the SBS protocol, as cited above, though the data of displaying charging current value exists, when the current value is smaller, there is no interface indicating whether the current value is small immediately before the completion of charging, or the current value is small because of the preliminary charge that is a recovery from the over-discharge. Accordingly, it is not possible for the conventional system to distinguish between the preliminary charge and the quick charge even in the preliminary charging state at a stage of enabling the communication between the battery and the system. 
     SUMMARY OF THE INVENTION 
     Accordingly, there is a need for a preliminary charging state apparatus, program and method. 
     The present invention has been achieved to solve the above-mentioned technical problems, and it is an object of the invention to clearly identify the preliminary charging state in a battery. 
     Also, it is another object of the invention to provide an electrical apparatus having a battery in which the preliminary charging state is informed to the user. 
     To attain the above objects, the present invention provides an electrical apparatus that is capable of receiving a battery for supplying electric power to a main unit by discharging after charging, comprising preliminary charge judging means for judging whether or not the battery is in a preliminary charging state that is a recovery from over-discharge, and display means for displaying an indication of preliminary charging if the preliminary charge judging means judges that the battery is in the preliminary charging state. 
     The display means displays the remaining charging time including the time required for the preliminary charge and the time required for the quick charge that is made later, whereby it is possible to solve the problem that the user mistakes the fault despite the preliminary charging. Displaying the remaining charging time “including” the time required for the preliminary charge and the time required for the quick charge involves displaying one remaining charging time by adding both the charging times, displaying both at the same time or switching both. 
     The electrical apparatus to which the invention is applied comprises a main unit that consumes the electric power, and a battery for supplying electric power to the main unit by discharging after charging, wherein the main unit judges that the battery is in the preliminary charging state that is a recovery from over-discharge if a predetermined communication with the battery is disabled after confirming that the battery is connected while being charged, and displays the judged result. 
     Further, this invention provides a computer that is connectable to a battery for charging and discharging, in which an electric power is supplied from the battery connected to a system main unit. At this time, the system main unit comprises a battery connection confirmation terminal for confirming that the battery is connected, a controller that judges that the battery is in a preliminary charging state if a predetermined communication with the battery is disabled after acquiring the information indicating that the battery is connected from the battery connection confirmation terminal, and a display for displaying that the battery is in preliminary charging state if the controller judges that the battery is in the preliminary charging state. 
     From another aspect, a computer to which the invention is applied comprises preliminary charge judging means for judging whether or not the battery is in a preliminary charging state that is a recovery from over-discharge, and display means for displaying an indication of the preliminary charging if the preliminary charge judging means judges that the battery is in the preliminary charging state. 
     The preliminary charge judging means judges the preliminary charging, on the basis of the information acquired via a communication line from a CPU provided in the battery, if the remaining capacity of the battery is less than a predetermined amount (e.g., remaining capacity 10%) and electric current flowing through the battery is in a predetermined range (e.g., range from 0A to 0.5A), whereby it is possible to grasp the preliminary charging on the system side in the form in which a communication with the CPU is enabled even with over-discharge. 
     Further, the invention can be grasped as a preliminary charging state display method. That is, the preliminary charging state display method to which the invention is applied is used with an electrical apparatus that is connectable to a battery for discharging after charging, in which electric power is supplied from the battery to a main unit, the method comprising judging whether or not the battery is in a preliminary charging state that is a recovery from over-discharge, and displaying an indication of the preliminary charging state if the battery is judged to be in the preliminary charging state. 
     This invention can be designated as a utility program being executed on a computer capable of mounting a battery for supplying electric power by charging and discharging. That is, this invention can be grasped as the utility program for use with the computer connectable to the battery for discharging after charging, in which electric power is supplied from the battery to a main unit, the utility program comprising a function of acquiring the information indicating that the battery is in preliminary charging that is a recovery from over-discharge, and a function of displaying that the battery is in preliminary charging state if the information indicating that the battery is in preliminary charging is acquired. 
     This utility program suffices to implement the above functions on the computer. A method of providing this program may involve reading the program stored in the storage medium such as a CD-ROM in a reader section for the storage medium such as a CD-ROM drive. Also, the program may be installed from the program transmission device via a network such as the Internet into the computer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other aspects, features, and advantages of the present invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings in which: 
     FIG. 1 is a block diagram showing a hardware configuration of a computer system  10  according to an embodiment of the invention; 
     FIG. 2 is a block diagram showing a circuit configuration of this power supply system; 
     FIG. 3 is a flowchart showing a process for realizing a preliminary charge display function; and 
     FIG. 4 is a view showing a display example of a preliminary charge (trickle charge) employing the utility program of the battery. 
    
    
     DETAILED DESCRIPTION 
     The use of figure reference labels in the claims is intended to identify one or more possible embodiments of the claimed subject matter in order to facilitate the interpretation of the claims. Such labeling is not to be construed as necessarily limiting the scope of those claims to the embodiments shown in the corresponding figures. The preferred embodiments of the present invention and its advantages are best understood by referring to the drawings, like numerals being used for like and corresponding parts of the various drawings. 
     FIG. 1 is a block diagram showing the hardware configuration of a computer system  10  according to an embodiment of the invention. A computer with this computer system  10  is in conformance with the OADG (Open Architecture Developer&#39;s Group) specification, for example, and is constituted as a notebook PC (notebook type personal computer) with a predetermined OS (Operating System). 
     In the computer system  10  as shown in FIG. 1, a CPU  11  operates as a brain of the entire computer system  10 , and executes the utility program and other programs under the control of the OS. The CPU  11  is interconnected to various components via three stages of buses, including an FSB (Front Side Bus)  12  as a system bus, a PCI (Peripheral Component Interconnect) bus  20  as a high speed I/O device bus, and an ISA (Industry Standard Architecture) bus  40  as a low speed I/O device bus. This CPU  11  effects the faster processing by storing a program code or the data in a cache memory. In recent years, an SRAM of about 128K bytes is accumulated as a primary cache inside the CPU  11 , but a secondary cache  14  of about 512K to 2M bytes is arranged via a BSB (Back Side Bus)  13  as a dedicated bus to supplement insufficient capacity. The secondary cache  14  may be connected to the FSB  12  by omitting the BSB  13  to avoid the package with many terminals, and reduce the costs. 
     The FSB  12  and the PCI bus  20  are linked via a CPU bridge (host-PCI bridge)  15  referred to as a memory/PCI chip. This CPU bridge  15  has a memory control function of controlling the access operation to a main memory  16  and comprises a data buffer to absorb a difference in data transfer rate between the FBS  12  and the PCI bus  20 . The main memory  16  is a writable memory employed as an area for reading an execution program for the CPU  11  or a working area for writing the processed data of the execution program. For example, the main memory  16  is composed of a plurality of DRAM chips, and mounts 64 MB as standard and can be extended up to 320 MB. The execution programs include the OS or various sorts of drivers for driving the hardware of peripheral devices, application programs intended for specific transactions, and the firmware such as a BIOS (Basic Input/Output System) stored in a flash ROM  44  as will be described later. 
     A video sub-system  17  implements the functions associated with the video, and contains a video controller. This video controller processes a drawing instruction from the CPU  11 , and writes the processed drawing information into a video memory, as well as reading the drawing information from the video memory to output the drawing data to a liquid crystal display (LCD)  18 . The liquid crystal display (LCD)  18  displays an indication of preliminary charging (hereinafter described) by a utility program executed in the CPU  11 . 
     The PCI bus  20  is capable of making the relatively fast data transfer, and is standardized as the data bus width of 32 bits or 64 bits, the maximum operation frequency of 33 MHz or 66 MHz, and the maximum data transfer rate of 132 MB/sec or 528 MB/sec. This PCI bus  20  is connected to an I/O bridge  21 , a card bus controller  22 , an audio sub-system  25 , a docking station interface (Dock, I/F)  26 , and a mini PCI connector  27 . 
     The card bus controller  22  is a dedicated controller for connecting a bus signal of the PCI bus  20  directly to an interface connector (card bus) of a card bus slot  23 , into which a PC card  24  can be loaded. The docking station interface  26  is a hardware for connecting a docking station (not shown) that is a function extended device of the computer system  10 . If a notebook PC is set in the docking station, various sorts of hardware elements connected to the internal bus of the docking station are connected via the docking station interface  26  to the PCI bus  20 . A mini PCI (miniPCI) card  28  is connected to the mini PCI connector  27 . 
     The I/O bridge  21  has a bridge function between the PCI bus  20  and the ISA bus  40 . Also, it comprises a DMA controller function, a programmable interrupt controller (PIC) function, a programmable interval timer (PIT) function, an IDE (Integrated Device Electronics) interface function, a USB (Universal Serial Bus) function, and an SMB (System Management Bus) interface function, and contains a real time clock (RTC). 
     The DMA controller function performs the data transfer between the peripheral device such as an FDD and the main memory  16  without intervention of the CPU  11 . The PIC function runs a predetermined program (interrupt handler) in response to an interrupt request (IRQ) from the peripheral device. The PIT function generates a timer signal at a certain period. Also, the interface realized by the IDE interface function has an IDE hard disk drive (HDD)  31  connected, and a CD-ROM drive  32  connected in ATAPI (AT Attachment Packet Interface). Instead of the CD-ROM drive  32 , other types of IDE device such as a DVD (Digital Versatile Disc) drive may be connected. An external storage device such as HDD  31  or CD-ROM drive  32  is accommodated in a storage place referred to as a “media bay” or a “device bay” within the notebook PC, for example. These external storage devices mounted as the standard may be attached exchangeably or exclusively with other devices such as an FDD or battery pack (intelligent battery). 
     Also, a USB port is provided in the I/O bridge  21 , and connected to a USB connector  30  provided on a wall face of the notebook PC, for example. Further, the I/O bridge  21  is connected via an SM bus to an EEPROM  33 . The EEPROM  33  carries the information, including a password registered by the user, a supervisor password, and the product serial number, and is non-volatile and electrically rewriteable. 
     Further, the I/O bridge  21  is connected to a power supply circuit  50 . The power supply circuit  50  comprises an AC adapter  51  being connected to the commercial power supply of AC 100V, for example, for making the AC/DC conversion, an intelligent battery  52  as a battery (secondary battery), a battery switching circuit  54  for charging this intelligent battery  52  and switching the power supply path from the AC adapter  51  and the intelligent battery  52 , and a DC/DC converter (DC/DC)  55  for generating a DC constant voltage such as +15V, +5V or +3.3V for use in the computer system  10 . 
     On the other hand, inside a core chip making up the I/O bridge  21  are provided an internal register for managing the power supply condition of the computer system  10 , and a logic (state machine) for managing the power supply condition of the computer system  10  including the operation of this internal register. This logic sends or receives various sorts of signal to or from the power supply circuit  50 , and recognizes the actual feeding state from the circuit  50  to the computer system  10  upon sending or receiving this signal. The power supply circuit  50  controls the power supply to the computer system  10  in accordance with an instruction from the logic. 
     The ISA bus  40  has a lower data transfer rate than the PCI bus  20  (e.g., the bus width of 16 bits and the maximum data transfer rate of 4MB/sec). An embedded controller  41  connected to a gate array logic  42 , a CMOS  43 , a flash ROM  44 , and a Super I/O controller  45  are connected to this ISA bus  40 . Further, the ISA bus  40  is also employed to connect the peripheral devices operating at relatively low rate, such as a keyboard/mouse controller. The Super I/O controller  45  is connected to an I/O port  46 , and controls the driving of FDD, the parallel data input/output (PIO) via a parallel port, and the serial data input/output (SIO) via a serial port. 
     The embedded controller  41  controls the keyboard, not shown, and is connected to the power supply circuit  50  to have a part of the power supply management function with the gate array logic  42  under the control of a built-in Power Management Controller (PMC). 
     A power supply system that is also a feature of this embodiment will be described below. 
     FIG. 2 is a block diagram showing the circuit configuration of this power supply system. This power supply system consists of the power supply circuit  50  as shown in FIG. 1, the embedded controller  41  and an AC adapter power stop circuit  80 . 
     The power supply system as shown in FIG. 2 comprises the AC adapter  51  that is the power supply device connected to the commercial power supply, and the intelligent battery  52  that is the secondary battery (battery, storage battery) composed of a lithium ion battery to be used through the repetitive operation of charging and discharging, and in conformance with the SBS (Smart Battery System). 
     The electric power from this AC adapter  51  and the intelligent battery  52  is output via the DC/DC converter  55  as shown in FIG. 1 to a main unit circuit of the computer system  10 . 
     Also, the power supply system as shown in FIG. 2 comprises, on the main unit system side, the embedded controller  41  for communicating via a communication line  74  with the intelligent battery  52 , a charger  73  for charging the intelligent battery  52 , a voltage measuring circuit  75  for measuring the voltage at the time of over-discharge and notifying it to the embedded controller  41 , and a battery connection confirmation terminal  76  for confirming whether or not the intelligent battery  52  is connected at the time of over-discharge. Moreover, it comprises the AC adapter power stop circuit  80  for refreshing the intelligent battery  52 , and a first diode (D 1 )  77  and a second diode (D 2 )  78  for rectifying the power supplied from the AC adapter  51  and the power supplied from the intelligent battery  52  to avoid conflict. 
     The AC adapter  51  as the power supply device is typically provided outside the electrical apparatus such as the notebook PC containing the computer system  10  that is a main unit (internal) system, but may be provided inside a housing for the electrical apparatus. This main unit system may be provided with an inlet capable of attaching or detaching a cable connector, for example. This inlet is configured so as to detachably accept a connector from the cable connected to the AC adapter  51 , if the AC adapter  51  is provided outside, or a connector directly connected to the commercial power supply, if the AC adapter  51  is provided inside the main unit system. The intelligent battery  52  is mounted on or dismounted from the main unit system as a battery pack, or may be provided within the housing of the electrical apparatus. 
     The internal constitution of the intelligent battery  52  that is a battery pack will be described below. As shown in FIG. 2, the intelligent battery  52  comprises a cell  61  composed of a plurality of unit cells that are charged and discharged, a CPU  62  for controlling the intelligent battery  52  and communicating via the communication line  74  with the embedded controller  41 , a current measuring circuit  63  for measuring the current value charged into or discharged from the intelligent battery  52 , and a voltage measuring circuit  70  for measuring the voltage of the cell  61 . The cell  61  is a lithium ion combination battery composed of six cells, two cells in parallel and three cells in series (1.8 Ah/cell), for example. 
     The CPU  62  mounted inside the intelligent battery  52  makes the A/D (Analog to Digital) conversion of an analog signal that is the measured result entered from the current measuring circuit  63  and the voltage measuring circuit  70 , and grasps the information regarding the battery, such as the capacity of battery. The grasped information regarding the battery is sent via the communication line  74  that is a communication path to the embedded controller  41  on the system side in accordance with the SBS protocol, for example. 
     The current measuring circuit  63  firstly generates a potential difference of voltage (IR) across a resistor (RS)  64  owing to a current I flowing from the cell  61 . This voltage is differentially amplified by an operational amplifier (AMP 1 )  65 . Also, a current I that is proportional to an output voltage of the operational amplifier (AMP 1 )  65  flows through the resistor (R 1 )  67  by means of an operational amplifier (AMP 2 )  66  and a transistor  68 . Finally, a current I of the intelligent battery  52  can be converted into the voltage ( 11 R 2 ) developed in a resistor (R 2 )  69 . This voltage ( 11 R 2 ) is output to A/D#2 port, and A/D converted by the Cpu  62 . 
     Also, the voltage measuring circuit  70  measures a voltage of the intelligent battery  52 . Specifically, a voltage of the cell  61  in the intelligent battery  52  is differentially amplified by an operational amplifier (AMP 3 )  71 , transformed into a lower voltage once, passed to A/D#1 port of the CPU  62 , and A/D converted by the CPU  62 . 
     Next, the AC adapter power stop circuit  80  will be described below. 
     This AC adapter power stop circuit  80  has a function of stopping the power supply from the AC adapter  51 . In the computer system  10  that is the main unit system, the first diode  77  and the second diode  78  are provided to supply electric power from the AC adapter  51  or the intelligent battery  52  as the secondary battery having a higher voltage value to the main unit circuit. In the case where the AC adapter  51  is connected, electric power is normally supplied from the AC adapter  51  via the first diode  77  to the main unit circuit, because the voltage of the AC adapter  51  is higher than the voltage of the intelligent battery  52 . 
     Herein, when a memory effect arises in the intelligent battery  52  as the secondary battery, the supply of electric power from the AC adapter  51  connected is stopped by the AC adapter power stop circuit  80 , enabling the intelligent battery  52  to make the complete discharge. That is, when it is desired to perform the intelligent battery  52  as the secondary battery to make the complete discharge, a High signal from the embedded controller  41  is supplied to the AC adapter power stop circuit  80 . The first transistor (TR 1 )  82  of the AC adapter power stop circuit  80  receives the High signal and is turned on. If this first transistor  82  is turned on, the second transistor (TR 2 )  83  is turned off, so that an FET (FET 1 )  81  is turned off. Thereby, the power supply from the AC adapter  51  is stopped to shut off the power supply to the first diode  77 , whereby electric power can be supplied from the intelligent battery  52  via the second diode  78  to the main unit circuit. 
     The preliminary charge in this embodiment will be described below. The over discharged battery (intelligent battery  52 ) must be subjected to preliminary charge (trickle charge, pre-charge) with a small current, because quick charge may damage the battery. The embedded controller  41  controls the charger  73  to make the preliminary charge of the intelligent battery  52 . That is, the preliminary charge can be said to be a recovery state from the over discharge. If a fixed voltage is reached with this preliminary charge, the embedded controller  41  controls the charger  73  to transfer to the normal quick charge for charging the intelligent battery  52 . The preliminary charge has the following two modes. 
     First of all, in the first mode, the embedded controller  41  detects the connection of the battery (intelligent battery  52 ) due to a voltage of the battery connection confirmation terminal  76 , but electric power is not supplied to the CPU  62  inside the intelligent battery  52  due to over discharge, whereby the CPU  62  and the embedded controller  41  can not be communicated with each other. In such a case, the embedded controller  41  uses the battery voltage measuring function with the voltage measuring circuit  75  provided inside the system to make the preliminary charge till the battery voltage reaches a specified voltage for starting the quick charge. That is, in the case where the connection of the intelligent battery  52  is detected, the communication with the intelligent battery  52  is not established, and/or the battery voltage is less than or equal to a specified voltage, the first mode is determined. 
     In the second mode, the over discharge has been effected, but the battery voltage may remain by some quantity to supply electric power to the CPU  62  of the intelligent battery  52 . That is, since the CPU  62  of the intelligent battery  52  is operating, the CPU  62  and the embedded controller  41  can communicate with each other, but because the battery voltage is low, the CPU  62  requests the embedded controller  41  for a small charging current value. Using the SBS (Smart Battery System) protocol, the preliminary charge in the second mode can be recognized, when “Remaining Capacity ( )&lt;10%” and “0A&lt;Average Current ( )&lt;0.5A” is satisfied, for example. 
     FIG. 3 is a flowchart showing a process for realizing the preliminary charge display function. In this process, first of all, it is determined whether or not the battery connection confirmation terminal  76  confirms the connection of the intelligent battery  52 , namely, whether or not the battery is connected (step  101 ). If the connection confirmation is not made, the procedure waits. If the connection confirmation is made, the embedded controller  41  issues an instruction of sending the device name (Device Name) via the communication line  74  to the CPU  62  of the intelligent battery  52 , and reads the device name via the communication line  74  (step  102 ). 
     Then, it is determined whether or not the device name is normally read (step  103 ). That is, though the device name is returned in the normal communication, if none is returned and the time-out occurs after the elapse of a specified time, the intelligent battery  52  can be regarded to be in the over discharge state. Thus, if the device name is not normally read at step  103 , the embedded controller  41  controls the charger  73  to make the trickle charge (pre-charge) (step  104 ), and a display of trickle charging is made on the liquid crystal display (LCD)  18  as shown in FIG. 1 (step  105 ). Thereafter, the procedure returns to step  102 . 
     If the device name is normally read at step  103 , the embedded controller  41  issues a command of asking “At which ampere is the battery charged?” via the communication line  74  to the CPU  62  of the intelligent battery  52 , and reads the charging current (step  106 ). Then, it is determined whether or not the read charging current is a request for the quick charge (step  107 ). If the request for the quick charge is not made, it is determined whether or not the request is for the trickle charge (step  108 ). If the request is for the trickle charge, the procedure transfers to step  104  to perform the trickle charge, and a display of trickle charging appears (step  105 ). 
     At step  107 , if the request is for the quick charge, the embedded controller  41  controls the charger  73  to perform the quick charge (step  109 ). Then, a display of quick charge appears on the liquid crystal display (LCD)  18  (step  110 ), and the procedure returns to step  102  to read the device name. 
     Next, a display of preliminary charge will be described below. 
     The embedded controller  41  recognizes the preliminary charging, if detecting any of the two modes as mentioned above. An indication of preliminary charging is displayed on the LCD provided for the electrical apparatus, or using the utility program for the battery that is executed by the CPU  11 . In a case of employing the LCD, yellow light indication signifies the quick charging, yellow flashing indication means the preliminary charging, and no light indication means the charging completion, for example. 
     FIG. 4 is a view showing a display example of preliminary charge (trickle charge) employing the utility program of the battery. The utility program acquires the information indicating the preliminary charging from the embedded controller  41 , and can display various kinds of information as to the preliminary charging, on the basis of this acquisition. Herein, a remaining charging time display  201 , a remaining capacity display  202  and a charging state display  203  are made. 
     In this example of the remaining charging time display  201  as shown in FIG. 4, the remaining charging time is displayed as “five hours” by adding the normal charging time (about three hours) and the preliminary charging time (two hours). Though the time till the completion of charging can not be usually displayed, the time including the preliminary charging time can be displayed in this embodiment. 
     In the remaining charging time display  201  having “inclusion” of the preliminary charging time, the normal charging time and the preliminary charging time are displayed in parallel, or the normal charging time and the preliminary charging time are switched for display, or both the times are added and displayed as shown in FIG.  4 . In the case where both are displayed in parallel, or switched, it is preferable to show whether the displayed time is the normal charging or the preliminary charging. Of course, the remaining charging time display  201  may be made by combination with the charging state display  203 . 
     Also, in the example of the remaining capacity display  202  as shown in FIG. 4, the remaining capacity of battery is indicated at “0%”. The preliminary charging time (two hours) remains at “0%”. In the example of the charging state display  203  as shown in FIG. 4, the “trickle charging” display that displays the preliminary charging is effected. And the current value “0.1A”, the voltage value “2.3V” and the wattage “0.23W” at present are displayed. With the display of these values, the user can recognize the conditions of the battery being charged. In this charge state display  203 , the battery transfers to the normal charge state after the preliminary charging state that is a recovery from the over discharge, whereby the “normal charging” or “quick charging” is displayed. Simply, the “charging” may be displayed. 
     The display of these values can be effected by the utility program executed by the CPU  11 . This utility program is stored in advance in the computer system  10 , or may be installed into the computer system  10  from the storage medium such as a CD-ROM or by the communication via the network, and stored in the HDD  31 , for example. 
     As described above in detail, in this embodiment, the preliminary charge is expressly identified, and the user is informed that the battery is in the preliminary charging state. 
     It will be further understood that various changes in the details, materials, and arrangements of the parts which have been described and illustrated in order to explain the nature of this invention may be made by those skilled in the art without departing from the principle and scope of the invention as expressed in the following claims.