Abstract:
A bus line address changing apparatus for use in an electronic instrument including a plurality of battery unit attaching sections configured to accommodate a plurality of battery units respectively composed of at least one battery. A bus line receives a communication signal from at least one battery unit. A body side controller receives the communication signal from the at least one battery unit via the bus line. A bus line address storing device stores a plurality of bus addresses allocated for and corresponding to the plurality of battery unit attaching sections. In addition, a bus address selecting and setting device is provided to select and set one of bus addresses according to the battery unit attaching section when the battery unit is attached to the electronic instrument and electrically connected to the bus line.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This document claims priority under 35 USC §119 to Japanese Patent Application No. 11-214360 filed on Jul. 28, 1999, the entire contents of which hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an electronic instrument, such as a notebook type personal computer, which includes a plurality of battery packs connectable to a bus line provided in a body of the electronic instrument and which is capable of displaying a remaining battery load, and in particular, relates to a bus line address changing apparatus for changing a bus line address separately set and stored in each battery pack. 
     2. Discussion of the Background 
     An electronic instrument, such as a notebook type personal computer, utilizing a battery pack as a driving power source, is well known. Namely, such an electronic instrument includes a function of displaying a remaining load on a display section of its body by connecting a battery to a bus line provided in the body. An electronic instrument capable of utilizing a plurality of such battery packs for prolonging an operational time period and displaying a remaining load of the battery has been also known. 
     A background electronic instrument, such as a notebook type personal computer, as one example of a mobile information instrument, is illustrated in FIG. 4, and is provided with a body (hereinafter referred to as an instrument body)  3  having a keyboard and similar devices, and a displaying section  4  pivotally and openably supported with respect to the instrument body  3 . The electronic instrument  1  sometimes includes a first battery pack  9  in a first attaching section  5 , composed of a slot or similar devices, provided at a front end of the instrument body  3 , and a second battery pack  11  in a second attaching section  7 , e.g., a slot. 
     Thus, the electronic instrument  1  is driven by receiving power supplied from both of the battery packs  9  and  11 . The battery packs  9  and  11  each respectively includes a pack side plus terminal  13 , a pack side minus terminal  15 , and a pack side communication terminal  17  for communicating with a bus line of the instrument body  3 . 
     An indication of the power of the battery packs  9  and  11  is supplied to the instrument body  3  and a remaining power or similar information of the battery packs  9  and  11  is transmitted to the instrument body  3 , when each terminal  13 ,  15 , and  17  is connected to a later mentioned corresponding terminal provided in the instrument body  3 . The instrument body  3  receives and displays the remaining load on an LCD or similar device in the display section  4 . The battery packs  9  and  11  respectively each have substantially a similar constitution which allows the electronic instrument  1  to execute an ordinal operation. Thus, when both battery packs  9  and  11  are attached to the instrument body  3  and are used, an operational time period of the instrument body  3  driven by the battery packs  9  and  11  can be prolonged when compared with a case that only one battery pack is attached to the instrument body  3 . 
     Furthermore, an electronic instrument in which only one battery pack is attached to the instrument body  3  and another is detached from its attaching section is known. In such a device, a driving device for a floppy disk or a CD-ROM is attached to the attaching section if the operational time period of the instrument body  5  is not required to be prolonged. 
     Further, in a background art using only one battery pack as illustrated in FIG. 5, a serial bus line  25  acting as a transmitting bus line, such as a system management bus line (hereinafter referred to as a SM bus line), for transmitting a communication signal and communication data, and a controller  27  for controlling the bus line  25 , are provided in the instrument body  3 . Further, a body side plus terminal  19  and a body side minus terminal  23  are provided in the first attaching section  5  of the instrument body  3  as a plus terminal and a minus terminal of the instrument body, respectively. 
     A body side communication terminal  21  for allowing transmission of a communication signal, communication data, and similar information with the battery pack  9  is also provided in the instrument body  3 . The body side plus terminal  19  is connected to a plus side power source line  33 , the body side minus terminal  23  is connected to a minus side power source line  35 , and the body side communication terminal  21  is connected to the bus line  25 . 
     In such an electronic instrument of the background art, a sequential number written in the parenthesis in FIG. 5 is utilized and represents a bus line address for an applicable device connected to the bus line  25 . For instance, the bus line controller  27  (with address 0001 000) recognizes that the battery pack  9 , which is one of the devices connected to the bus line  25 , has an address (0001 011). A communication signal and similar information transmitted to the bus line controller  27  from the battery pack  9  may include the bus line address (0001 011). Thus, the bus line controller  27  can surely identify a communication signal transmitted from the battery pack  9  referring to the bus line address (0001 011) included in the communication signal, even if a variety of communication signals are transmitted to the bus line controller  27  from each device via the bus line  25  commonly used by the plurality of devices. 
     As examples of a device supplied with a power source, for instance, under control of the bus line controller  27 , a cold cathode ray tube driver  29  (with address 0101 101) for illuminating a display section  4 , such as a LCD, from an inside of the instrument body  3 , and a card connecting terminal power source controller  31  (with address 1000 0xx), such as a PCMCIA (Personal Computer Memory Card International Association) socket, are connected to the bus line  25 . 
     When the battery pack  9  is attached to the first attaching section  5  of the instrument body  3 , each terminal  13 ,  15 , and  17  is electrically connected to each terminal  19 ,  23 , and  21  oppositely arranged in the instrument body  3 , respectively. When the battery pack  9  and the instrument body  3  are electrically conducted in such a manner, the instrument body  3  can be supplied with electrical power from the battery pack  9  via the coupling of terminals  13  and  15 , and the coupling of terminals  19  and  23 . In addition, information, such as remaining load of the battery pack  9 , can be transmitted to the instrument body  3  via the terminals  17  and  21 . 
     As illustrated in FIG. 6, the battery pack  9  includes a battery  37  including a charge-impossible battery as a primary battery, such as a manganese battery or an alkaline battery, and a chargeable battery as a secondary battery, such as a nickel cadmium battery or a lithium battery, connected with each other in parallel or serially, in addition to the above-mentioned pack side plus and minus terminals  13  and  15 , and the pack side communication terminal  17 . 
     Further, a detecting section  43  for detecting a voltage or an output current or the like generated between both poles of the battery  37 , an arithmetic element, such as a micro-computer, and a memorizing element, such as a memory (each not shown), are provided in the battery pack  9 . The arithmetic element may calculate a remaining load of the battery  37  as a result of detection, executed by the detecting section  43 , of the voltage or output current, for example, generated between the both poles of the battery  37 . The arithmetic element may also control the detecting section  43  and communication of signals in a prescribed manner. 
     A control section  47  may have a memory for storing a bus line address (0001 011) and so on, and a bus line  45  acting as a transmission path  45  connecting the control section  47  with the detecting section and with the pack side communication terminal  17  for communicating a communication signal and similar information. The battery pack  9  may further include a plus side power source line  39  constituting a transmitting path for a power source current of the plus pole side, and a minus side power source line  41  constituting a transmitting path for a power source current of the minus pole side. 
     FIG. 7 illustrates an interior constitution of an instrument body  3  of the related electronic instrument to which two battery packs are attached. The first battery pack  9  is attached to the first attaching section  5  as illustrated in FIG.  5 . In addition, the second battery pack  11  is attached to the second attaching section  7 . Further, a selector  49 , composed of a semiconductor switch or a similar device is added to a portion of the bus line  25 , for selectively communicating a communication signal, such as remaining load, transmitted from the first and second battery packs  9  and  11  to the bus line controller  27 . 
     Owing to the selector  49 , either the communication signal representing the remaining load of the first battery pack  9  or that of the second battery pack  11  is transmitted to the bus line controller  27 . The reason why both the communication signals representing these remaining loads can not simultaneously be transmitted and selectively transmitted to the bus line controller  27  is as follows. If these communication signals are simultaneously transmitted on a same bus line  25 , a conflict of addresses occurs because both addresses for the first battery pack  9  and the second battery pack  11  are generally the same (e.g. 0001 011),. In other words, since the addresses for the battery packs  9  and  11  illustrated in FIG. 7 are the same, the bus line controller  27  cannot discriminate the above-noted communication signals, unless the selector  49  selects one of these bus line addresses and changes. 
     In addition, this causes a probability of an erroneous operation and an overdriving of the bus line controller  27 . Then, the selector  49  may select a communication signal, and transmit the selected communication signal to the bus line controller  27  so that the bus line controller  27  does not erroneously operate and overdrive. 
     Further, an additional problem occurs such that a hardware construction of the instrument body  3  and a control use software for the bus line controller  27  and similar devices become complex due to having to provide the selector  49  in the instrument body  3 . To resolve such problems, it is possible to simply differentiate addresses for the battery packs  9  and  11 , respectively. 
     However, the bus line controller  27  cannot recognize a battery pack attached to each attaching section if a bus line address as an ID for discrimination of each battery pack is optionally changed at the battery pack side because the bus line controller  27  generally recognizes that a bus line address of a device, i.e., a battery pack  9 , attached to the first attaching section  5  is (xxxx xxx), and that of the battery pack  11  attached to the second attaching section  7  is (yyyy yyy). Accordingly, when an address for each battery pack is differentiated at the battery pack side, an address for a battery pack attached to the first attaching section  5  should be limited to (xxxx xxx), and that for a battery pack attached to the second attaching section  7  should be limited to (yyyyy yyy). 
     However, when a bus line address for each battery pack  9  and  11  is differentiated (at the battery pack side), a single battery cannot be used for both the battery packs, i.e. both of the battery packs respectively cannot be equally constituted and common. This may result in requiring two kinds of battery packs when designing, producing, distributing, and stocking, and may be a cause of increasing cost of the electronic instrument. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the above-noted and other problems and one object of the present invention is to address and resolve such problems. 
     A further object of the present invention is to provide a novel bus line address changing apparatus for use in an electronic instrument including a plurality of battery unit attaching sections configured to accommodate a plurality of battery units respectively composed of at least a battery. 
     The novel bus line address changing apparatus may include a bus line configured to receive a communication signal from at least one battery unit. A body side controller is configured to receive the communication signal from at least one battery unit via the bus line. A bus line address storing device is configured to store a plurality of bus addresses allocated for and corresponding to the plurality of battery unit attaching sections. A bus address selecting and setting device is configured to select and set one of the bus addresses according to the battery unit attaching section when the battery unit is attached and electrically connected to the bus line. 
     In another embodiment, the bus line address selecting and setting device may include a detecting device provided in each battery unit and configured to detect at least a voltage differently set in the electronic instrument corresponding to each battery attaching section, and a selecting device configured to select one of the bus addresses corresponding to the detected voltage. 
     In yet another embodiment, the bus address-storing device is provided in each battery unit. 
     In yet another embodiment, the battery units respectively each include a communication controller configured to transmit the communication signal with a selected and set bus address to the body side controller. 
     In yet another embodiment, the battery units respectively each include a battery load detecting device configured to detect remaining battery load, and the battery information to be transmitted to the body side controller includes the remaining battery load. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
     FIG. 1 is a block chart illustrating an interior constitution of a principal portion of an electronic instrument of the first embodiment according to the present invention; 
     FIG. 2 is a block chart illustrating an interior constitution of a battery pack of the first example attached to the electronic instrument illustrated in FIG. 1 according to the present invention; 
     FIG. 3 is a block chart illustrating an interior constitution of a battery pack of the second example attached to the second embodiment according to the present invention; 
     FIG. 4 is a perspective view illustrating an entire constitution of one example of the electronic instrument to which the present invention can be applied; 
     FIG. 5 is a block chart illustrating an interior constitution of a principal part of a background electronic instrument; 
     FIG. 6 is a block chart illustrating an interior constitution of a background battery pack; and 
     FIG. 7 is a block chart illustrating an interior constitution of a principal part of a background electronic instrument. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, wherein like reference numerals and marks designate identical or corresponding parts throughout several views, in FIG. 1 an electronic instrument of a first embodiment of the present invention may be provided with a pair of body side detection terminals  53  disposed in first and second attaching sections  5  and  7 , respectively. Such body side detection terminals  53  may detect different voltages as information for determining corresponding bus line addresses for respective battery packs  59  and  61 . 
     Further, a first changing circuit  55  for a first battery pack  59  use (grounded circuit) connecting to the body side detection terminal  53  may be provided adjacent to the first attaching section  5 . A second address changing circuit  57  for a second battery pack  61  use (open terminal) connecting to the body side detection terminal  53  may be provided adjacent to the second attaching section  7 . A pair of pack side detection terminals  51  are provided in the first and second battery packs  59  and  61  at sections opposing the body side terminals  53 , respectively. As illustrated in FIG. 2, a memory and similar devices may be provided in the control section  47  of each battery pack  59  and  61 , and may store a pair of bus line addresses, e.g., (0001 011) selected and set when the battery pack  59  ( 61 ) is attached to the first attaching section  5 , and e.g., (0001 010) selected and set when the battery pack  59  ( 61 ) is attached to the second attaching section  7 . 
     A pull-up resistor  69  for pulling up a voltage of the pack side detection terminal  51  may be connected between a power source line  65  and the pack side detection terminal  51 , and both the pack side detection terminal  51  and the control section  47  are connected with each other via a connecting line  67  in each battery pack  59  and  61 . Accordingly, a value of a voltage of the pack side detection terminal  51  induced when a battery pack is not attached to the instrument body  63  may be determined from both a resistance value of the pull-up resistor  69  and the value of a voltage of the power source line  65 . Further, the voltage value of the pack side detection terminal  51  may be detected by the control section  47 . 
     Even though both the first and second battery packs  59 ,  61  are distinctively described from a point of explanation of a convenient view, each interior constitution of the battery packs  59 ,  61  is substantially the same. 
     The address changing circuit  57  may be configured to determine a bus line address (0001 010) for the battery pack  61  attached to the second attaching section  7 . The changing circuit  55  may be configured to generate a bus line address (0001 011) for the battery pack  59  attached to the first attaching section  5 . Specifically, the changing circuit  55  may be a grounding circuit for setting the voltage value of the pack side detection terminal  51  to zero by grounding when the battery pack  59  is attached, and the address changing circuit  57  may be an open circuit for keeping the voltage value of the pack side detection terminal  51  as it is when the battery pack  61  is attached. 
     The other constitutional elements of the electronic instrument  1  and the battery pack  59  illustrated in FIGS. 1 and 2 may be substantially the same as the corresponding elements in the background art illustrated in FIGS. 5 to  7 . 
     When the first battery pack  59  is attached to the first attaching section  5 , the battery pack side detection terminal  51  thereof connects to the body side detection terminal  53 , and thereby the voltage of the battery pack side detection terminal  51  lowers to zero volts by being grounded through changing circuit  55 . To the contrary, when the second battery pack  61  is attached to the second attaching section  7 , the battery pack side detection terminal  51  thereof connects to the body side detection terminal  53 , but the voltage of that battery pack side detection terminal  51  thereof is not lowered to zero by being connected to changing circuit  57 , which is an open terminal. Namely, the voltage determined by both the power source line  65  and the resistance of the pull-up resistor  69  may be kept in the latter case. 
     The control section  47  of the first battery pack  59  may detect and recognize the voltage value of the detection terminal  51  as zero. Then, the control section  47  may select and set a bus address from the two different addresses (0001 010) and (0001 011) stored in its memory to select the address corresponding to the zero volts at its detection terminal  51 , so that the address (0001 011) representing the battery pack  59  attached to the first attaching section  5  is included in a communication signal. 
     To the contrary, the control section  47  of the second battery pack  61  may detect and recognize the voltage value of the detection terminal  51  as maintained and not lowered to zero. Then, its control section  47  may select and set the address corresponding to a non-zero voltage at its detection terminal  51 , so that the address (0001 010) representing a battery pack  61  attached to the second attaching section  7  from the different addresses (0001 010) and (0001 011) stored in its memory is selected to be included in a communication signal. 
     Accordingly, the bus line controller  27  can receive a communication signal and recognize whether the communication signal received is transmitted from the first battery pack  59  attached to the first attaching section  5  or is transmitted from the second battery pack  61  attached to the second attaching section  7 . 
     As mentioned above, the first and second battery packs  59  and  61  are distinctively attached to the first and second attaching section  5  and  7 , respectively. However, since both battery packs  59  and  61  have the same constitution, the first battery pack  59  can be attached to the second attaching section  7 , and the second battery pack  61  can be attached to the first attaching section  5 , for example. In that case, since the voltage of the detection terminal  51  is maintained and is not being lowered in the first battery pack  59  attached to the second attaching section  7 , a bus line address (0001 010) representing a battery pack attached to the second attaching section  7  is selected and included in the communication signal. To the contrary, in that situation, since the voltage of the detection terminal  51  is lowered to zero in the second battery pack  61  attached to the first attaching section  5 , a bus line address (0001 011) representing a battery pack attached to the first attaching section  5  is selected and is included in the communication signal. 
     Thus, according to this embodiment, since a bus line address for a battery pack is differentiated depending on its attaching sections  5  and  7 , the bus line addresses do not conflict and each battery pack  59 ,  61  can be supervised together on the same bus line, even if the same constitutional battery pack is used. Therefore, a battery of a single construction can be attached to a plurality of attaching sections. 
     The second embodiment of the present invention is now described referring to FIG. 3, FIG. 3 is a block chart illustrating an interior constitution of a battery pack attached to an electronic instrument of a type in which two battery packs are attached. As shown in FIG. 3, a control section  47  in each battery pack  59  and  61  may include a voltage discriminating (detecting) section  63  composed of an analog/digital (hereinafter referred to as an A/D) converter. A switching circuit  55  may be provided inside the first attaching section  5  of the instrument body  63 . Such a switching circuit  55  may be composed of a first voltage-dividing resistor  71  of, e.g., 10 kilo-ohm connected between a body side detection terminal  53  and ground. 
     An address switching circuit  57  may be provided inside the second attaching section  7  of the instrument body  63  . Such an address switching circuit  57  may be composed of a second voltage-dividing resistor  73  of, e.g., 100 kilo-ohm connected between the body side detection terminal  53  and ground. The other constitutional elements of the battery pack  59  and  61  illustrated in FIG. 3 may be the same as in the first embodiment. 
     In this embodiment, the voltage detecting section  63  in the control section  47  may detect voltages set by the pull-up resister  69  and the voltage dividing resisters  71  or  73  and induced at the connecting line  67  ranging from the power source line  65  to ground. 
     Thus, according to this embodiment, a disadvantage that the control section  47  simply detects a kind of voltage, i.e., ground voltage and open voltage, described in the first embodiment may be overcome because the control section  47  can detect a plurality of voltages, which are set by the pull-up resistor  69  and the voltage dividing resistor  71  or  73 , and which range from the voltage of the power source line  65  and ground, in accordance with a number of battery attaching sections. 
     When a voltage caused by the first voltage dividing resistor  71  is detected, a control section  47  may properly select and set a bus address from the pair of bus addresses (0001 010) and (0001 011) stored in the memory so that the address (0001 011) representing a battery pack attached to the first attaching section  5  is selected and included in a communication signal transmitted therefrom. 
     Further, when a voltage caused by the second voltage dividing resistor  73  is detected, a control section  47  may properly select and set a bus address from the above mentioned pair of addresses so that the bus address (0001 010) representing a battery pack attached to the second attaching section  7  is included in a communication signal. 
     In this embodiment, not only can the voltage to be detected and set by the changing circuits  55  and  57  be optionally changed to a desired value as a result of being able to detect the optional voltage, but also a number of levels of voltage to be detected can be optionally increased corresponding to the number of attaching sections for attaching respective batteries. In that case, a number of bus line addresses to be stored may be also increasingly utilized according to an increase in the number of attaching sections. Specifically, when a number of the attaching sections is increased up to three, a new address (0001 001) may be stored in a memory of the control section  47  of a battery pack attached to the third attaching section in addition to the currently used addresses (0001 010) and (0001 011) for the battery packs attached to the first and second attaching sections, respectively. Further, a resistor of, e.g., 50 kilo-ohm may be utilized as a voltage dividing resistor of the changing circuit for the third battery pack. 
     Thus, in this embodiment using the bus line address changing apparatus, a voltage of the pack side detection terminal  51  of the first battery pack  59  may have a value divided by both the pull-up resistor  69  and the first voltage dividing resistor  71 , when the first battery pack  59  is attached to the first attaching section  5 . Similarly, the voltage of the pack side detection terminal  51  of the battery pack  61  may have a value divided by both the pull-up resistor  69  and the second voltage dividing resistor  73 , when the second battery pack  61  is attached to the second attaching section  7 . 
     Accordingly, since the bus line address of the battery pack is differentiated depending upon its attaching sections  5  and  7 , the bus line address does not conflict and accordingly each battery pack  59 ,  61  can be supervised on the same bus line, even if the same constitutional battery pack is optionally attached to a plurality of attaching sections of the electronic instrument. 
     Further, even if a number of battery packs is increased, a bus line address for each battery pack can be readily differentiated according to each attaching section. 
     Further, the remaining charge can be included in the communication signal as information transmitted from a battery pack to the bus line controller of the instrument body. 
     Further, this invention is not limited to communicating such a remaining charge, and any condition of the battery pack such as voltage, current and temperature information, etc. can be included therein. 
     Further, constitutions of the pack side detection terminal  51  and the body side detection terminal  53  can be different from those of the pack side communication terminal  17  and the body side communication terminal  21 . 
     Further, one of pins in the each pack side communication terminal  17  and the body side communication terminal  21  can be used as a pack side detection terminal  51  and a body side detection terminal  53 , if both the terminals  17  and  21  are configured to include a plurality of pins. 
     Further, a bus line address can be properly changed by increasing or decreasing a number of signal lines connecting when the battery pack is attached to the attaching section. 
     Obviously numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.