Abstract:
This patent specification describes a power adapter which includes a power unit including a converter to supply power to a computer and a peripheral unit configured to communicate with the computer and to be controlled by the computer. Further, the power adapter includes a multiplexing-demultiplexing circuit configured to multiplex and demultiplex a power signal with a data or control signal.

Description:
FIELD 
     This patent specification describes a power adapter including peripheral unit capable of supplying power for computer and the peripheral unit. 
     BACKGROUND 
     A power adapter is widely used as a power supplier for compact desktop PCs (personal computer), notebook PCs and personal information equipment. The power adapter is generally prepared only to supply power to the PCs and equipments. However, a performance of the power adapter is relatively low whereas the power adapter has a large volume and is heavy. 
       FIG. 1  illustrates a conventional compact computer system. The compact computer system includes a power adapter  110 , a computer  104  and a cable  116 . The cable  116  connects the power adapter  110  to the computer  104  so as to supply power to the computer  104 . A cable  114  may be employed separately from the cable  116  to connect the computer  104  to a peripheral device  112 . If the peripheral device  112  is a high power device, a separate power adapter may be employed to supply a necessary power to the peripheral device  112 . 
     A variety of adapters including a peripheral circuit have been disclosed. One example is an USB (universal serial bus) hub adapter. In the USB hub adapter, a power is supplied simply to work an USB hub circuit included in the USB hub adapter. Similarly, in a network adapter, a power is supplied simply to work the network circuit. In a LAN (local area network) adapter, a power is supplied simply to work the LAN circuit. In an interface apparatus of an uninterruptible power source, a power is supplied simply to work an interface circuit. Further, the interface apparatus does not have a converting function on a frequency and a voltage of the power being supplied. Thus, those adaptors do not supply power to the computer but only to the circuit mounted on the adapters. 
     SUMMARY 
     This patent specification describes a novel power adapter which includes a power unit including a converter to supply power to a computer and a peripheral unit configured to communicate with the computer and to be controlled by the computer. 
     This patent specification further describes a novel cable which includes a power line configured to supply a power from a power adapter to a computer and a transmission line integrated with the power line and configured to communicate between the computer and a peripheral unit arranged at the power adapter. 
     Further, this patent specification describes a novel computer system which includes a computer, a power adapter including a power unit configured to supply power and a peripheral unit configured to communicate with the computer and to be controlled by the computer and a cable including a power line to supply power and a transmission line to transmit data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the disclosure 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  illustrates schematically a conventional compact computer system; 
         FIG. 2A  illustrates an oblique perspective schematic view of a compact computer system according to a first exemplary embodiment of the present disclosure; 
         FIGS. 2B ,  3 A,  3 B and  4  illustrate oblique perspective schematic views of additional examples of a compact computer system according to the first exemplary embodiment; 
         FIGS. 5A through 5C  illustrate oblique perspective schematic views of cables according to a second exemplary embodiment; 
         FIGS. 6A through 6C  illustrate oblique perspective schematic views of cables according to a third exemplary embodiment; 
         FIGS. 7A through 9B  illustrate oblique perspective schematic views of cable-output connectors and cable-input connectors according to a fourth exemplary embodiment; 
         FIG. 10  illustrates an oblique perspective schematic view of a compact computer system according to a fifth exemplary embodiment; 
         FIG. 11  illustrates an oblique perspective schematic view of a compact computer system in which two computers are used according to a sixth exemplary embodiment; 
         FIG. 12A  illustrates schematically a power adapter which includes a multiplexing-demultiplexing circuit; 
         FIG. 12B  illustrates schematically a computer which includes a multiplexing-demultiplexing circuit; 
         FIG. 13A  illustrates schematically a power adapter which includes another multiplexing-demultiplexing circuit; 
         FIG. 13B  illustrates schematically a computer which includes another multiplexing-demultiplexing circuit; 
         FIG. 14  illustrates a block diagram of an example of a compact computer system; 
         FIG. 15  illustrates an oblique perspective schematic view of a power adapter according to a seventh exemplary embodiment; and 
         FIG. 16  illustrates an oblique perspective schematic view of another example of a power adapter according to the seventh exemplary embodiment showing a more detailed configuration. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In describing preferred embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner. Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, particularly to  FIG. 2A , a power adapter according to an exemplary embodiments is described. 
       FIG. 2A  illustrates an oblique perspective schematic view of an example of a compact computer system which includes a power adapter  8 , a computer  4  and a cable  6 , according to a first exemplary embodiment of the present disclosure. The power adapter  8  includes a power unit  10  and a peripheral unit  12  therein. The cable  6  connects the power adapter  8  to the computer  4 . The power unit  10  includes a main power input line and a power converter (not shown). 
     The power converter converts a power input from the main power input line to a necessary power. The power unit  10  supplies the power to the computer  4  similarly to a conventional power adapter (AC adapter). Meanwhile, the peripheral unit  12  works as a part of the computer  4  and performs a peripheral function, for example, an USB (universal serial bus) connecting function. 
     The power adapter  8  is connected to the computer  4  using only one cable in the first exemplary embodiment. Namely, power is supplied to the computer  4  from the power adapter  8  through the cable  6 . Moreover, digital data is transmitted between the peripheral unit  12  and the computer  4  through the cable  6 . 
     The computer  4  includes a peripheral controller (not shown) and a power input circuit (not shown). The peripheral controller controls data transmission with the peripheral unit  12  which is included in the power adapter  8 . The power unit  10  and the peripheral unit  12  can be integrated into one device as shown in  FIG. 2A  so that the total system can be made smaller and more lightweight. 
       FIG. 2B  illustrates another example of a compact computer system wherein a different power from the power for the computer  4  is supplied to the peripheral unit  12 . In this example, a power branch unit  20  is arranged in the power unit  10  of the power adapter  8 . Power is supplied to the computer  4  and power is also supplied to the peripheral unit  12 , in each instance, from the power branch unit  20 . The power output from the power branch unit  20  is not necessary to be equal but can be different kinds of powers, for example, with a different voltage and a different frequency. 
       FIGS. 3A and 3B  illustrate respective oblique perspective schematic views of additional examples of a compact computer system which includes a power unit  300 , a computer  4  and a cable  6 . The power unit  300  supplies power to the computer  4  through the cable  6 , similar to a conventional power adapter. Further, the power unit  300  includes a peripheral connecting connector  22 . 
     In  FIG. 3B , a peripheral unit  312  can be connected to the power unit  300  via the peripheral connecting connector  22 . The cable  6  includes a power line  16  and a data transmission line  14 , and the data transmission line is extended to the peripheral connecting connector  22  so that the peripheral unit  312  can communicate with the computer  4 . The peripheral connecting connector  22  is connected to a power branch unit  20  arranged in the power unit  300  so that the power is supplied to the peripheral unit  312  from the power unit  300  via the peripheral connecting connector  22 . 
       FIG. 4  illustrates an oblique perspective schematic view of another example of a compact computer system according to a first exemplary embodiment of the present disclosure. The cable  6  is detachably arranged with the power adapter  8 . Namely, the cable  6 , in which the power supply line  16  and the data transmission line  14  is integrated, can be detached from the computer  4  and the power adapter  8 . As a result, a variety of cables are applicable. If a peripheral function is not needed, a data transmission line may not be necessary. A cable which includes a power supply line only may be employed. 
       FIGS. 5A through 5C  illustrate oblique perspective schematic views of cables  306  and  366 , according to a second exemplary embodiment of the present disclosure. The cables  306  and  366  connect the power adapter  8  or the power unit  300  to the computer  4 . In  FIGS. 5A through 5C , the power adapter  8 , the power unit  300  and the computer  4  are shown by dashed lines. 
     The cable  306  in  FIG. 5A  includes a power supply line  16  and a data transmission line  14 . The two lines  14  and  16  are integrated. The power supply line  16  connects the power unit  10  to the computer  4  and the data transmission line  14  transmits transmission data between a peripheral unit  12  and the computer  4 . The cable  306  in  FIG. 5A  is a single cable so as to contribute to obtain a compact system which is lightweight. 
     The cable  306  in  FIG. 5B  includes a power supply line  16  and a data transmission line  14 . The two lines are integrated. The power supply line  16  connects the power unit  300  having a peripheral connecting connector  22  to the computer  4 . The data transmission line  14  transmits transmission data between the peripheral connecting connector  22  and the computer  4 . The cable  306  in  FIG. 5B  is also a single cable so as to contribute to make the system compact and lightweight. 
     The cable  366  of  FIG. 5C  includes a power pipe  26  and a data pipe  24 . The power pipe  26  includes a power supply line  16  which supplies power from the power unit  10  to the computer  4 . The data pipe  24  includes a data transmission line  14  which transmits signals between the computer  4  and the peripheral unit  12 . The data pipe  24  and the power pipe  26  are integrated and are detachably included in the cable  366 . 
     If only the power unit  10  is used, the data pipe  24  may be detached so as to make the cable  366  compact and lightweight. If only the peripheral unit  12  is used, the power pipe  26  may be detached so as to make the cable  366  compact and lightweight. Further, the peripheral unit  12  may be used as a part of another computer system by separating the data pipe  24  and the power pipe  26 . 
       FIGS. 6A through 6C  illustrate oblique perspective schematic views of cables  30  and  33 , according to a third exemplary embodiment of the present disclosure. The cables  30  and  33  connect a power adapter  8  or a power unit  300  to the computer  4 . In  FIGS. 6A through 6C , the power adapter  8 , the power unit  300  and the computer  4  are shown by dashed lines. 
     The cable  30  in  FIG. 6A  includes a power supply line  16  and a data transmission line  14 , similar to the examples shown in  FIGS. 2A and 2B . The two lines are integrated. The power supply line  16  connects the power unit  10  to the computer  4  and the data transmission line  14  transmits transmission data between the peripheral unit  12  and the computer  4 . In the example of  FIG. 2B , the peripheral unit  12  of the power adapter  8  receives a different power from the power to the computer  4  and the power to the peripheral unit is supplied from the power unit  10  through the power branch unit  20 . However, in the example of  FIG. 6A , the power for the peripheral unit  12  is supplied from the computer  4 . 
     The data transmission line  14 , a first power line  16  and a second power line  28  are integrated in the cable  30 . The cable  30  in  FIG. 6A  is a single cable so as to contribute to make a small, lightweight, system similar to the cable  6  shown in  FIG. 5A . 
     The cable  33  in  FIG. 6B  includes a first power pipe  26 , a data pipe  24  and a second power pipe  32 . The first power pipe  26 , the data pipe  24  and the second power pipe  32  are integrated and are configured to be detachable from the cable  33 . The first power pipe  26  includes a first power supply line  16  which supplies a first power from the power unit  10  to the computer  4 . The data pipe  24  includes a data transmission line  14  which transmits signals between the peripheral unit  12  and the computer  4 . The second power pipe  32  includes a second power supply line  28  which supplies a second power from the computer  4  to the peripheral unit  12 . 
     If only the power unit  10  of the power adapter  8  is used, the data pipe  24  and the second power pipe  32  may be detached so as to make the cable  33  compact and lightweight. If only the peripheral unit  12  of the power adapter  8  is used, the power pipe  26  may be detached so as to make the cable  30  compact and lightweight. Further, the peripheral unit  12  may be used as a part of another computer system by separating the data pipe  24 , the first and second power pipes  26  and  32 . As shown in  FIG. 6C , if the power adapter does not include a peripheral unit and is used only as a power supplier, the data pipe  24  and the second power pipe  32  may be detached so as to make the cable  33  compact and lightweight. 
       FIGS. 7A to 9B  illustrate oblique perspective schematic views of cable-output connectors  34 ,  36  and  42  and cable-input connectors  38 ,  40  and  44  according to a fourth exemplary embodiment of the present disclosure. The cable-output connectors  34 ,  36  and  42  are arranged at an end of the cable. The cable-input connectors  38 ,  40  and  44  are arranged at a sidewall of the computer  4 . The cable is connected to the computer  4  with the cable-output connectors  34 ,  36  and  42  and the cable-input connectors  38 ,  40  and  44 . In  FIGS. 7A to 9B , the connectors are shown with solid line, and the power adapter  8 , the power unit  10 , the computer  4  and the cables are shown by dashed line. 
       FIG. 7A  illustrates a data transmission connector  34  and a power connector  36  which are the cable-input connectors and are integrated. The data transmission connector  34  connects the data transmission line  14  to the computer  4  and the power connector  36  connects the power line  16  to the computer  4 .  FIG. 9A  illustrates a data input/output connector  38  and a power input connector  40  which are the cable-input connectors and are integrated. The data input/output connector  38  and the power input connector  40  are arranged at a sidewall of the computer  4 . The data transmission connector  34  and the power connector  36  are connected to the data input/output connector  38  and the power input connector  40  respectively. 
     The data transmission connector  34  and the power connector  36  are integrated so as to make the cable, the power adapter and the computer compact and lightweight. Similarly, the data input/output connector  38  and the power input connector  40  are integrated so as to make the cable and the computer compact and lightweight. 
       FIG. 8A  illustrates a data transmission connector  34 , a power connector  36  and a peripheral-power-supply connector  42  which are the cable-input connectors and are integrated. The peripheral-power-supply connector  42  connects the power line  28  to the computer  4 . The computer  4  supplies the power to the peripheral unit  12  through the peripheral-power-supply connector  42 .  FIG. 9B  illustrates the data input/output connector  38 , the power input connector  40  and a peripheral-power-output connector  44  which are the cable-input connectors and are integrated. The peripheral-power-output connector  44  is arranged at a sidewall of the computer  4  and is connected to the peripheral-power-supply connector  42 . 
     The data transmission connector  34 , the power connector  36  and the peripheral-power-supply connector  42  are integrated so as to make the cable, the peripheral unit, the power adapter and the computer compact and lightweight. Similarly, the data input/output connector  38 , the power input connector  40  and the peripheral-power-output connector  44  are integrated so as to make the cable and the computer compact and lightweight. 
       FIG. 7B  illustrates the data transmission connector  34  and the power connector  36  which are configured to be detached from each other. It is a difference from the connectors of  FIG. 7A . Further,  FIG. 8B  illustrates the data transmission connector  34 , the power connector  36  and the peripheral-power-supply connector  42  which are configured to be detached from each other. It is a difference from the connectors of  FIG. 8A . Advantages to form the data transmission connector  34  and the power connector  36  detachable as shown in  FIG. 7B  will be described. 
     If the computer  4  needs a function of a power adapter only, the data transmission connector  34  may be detached so as to make a connection mechanism between the cable and the computer  4  compact and lightweight. By removing the data transmission connector  34 , the power adapter  8  may be used simply as a power adapter and may be connected to another computer. Further, the power adapter  8  can be applied to a computer which has a power input connector only. 
     If the computer  4  needs a functionality of a peripheral device, the power connector  36  may be detached so as to make a connection mechanism between the cable and the computer  4  compact and lightweight. By removing the power connector  36 , the peripheral unit may be simply used as a peripheral unit and may be connected to another computer independently. Further, the peripheral unit can be connected to a computer which has a peripheral input connector only. 
     Advantages that the data transmission connector  34 , the power connector  36  and the peripheral-power-supply connector  42  are formed to be detachable as shown in  FIG. 8B  will be described. 
     If the computer  4  needs a functionality of a power adapter only, the data transmission connector  34  and the peripheral-power-supply connector  42  may be detached so as to make a connection mechanism between the cable and the computer  4  compact and lightweight. By removing the data transmission connector  34  and the peripheral-power-supply connector  42 , the power adapter  8  may be simply used as a power adapter. Further, the power adapter  8  can be applied to a computer which has a power input connector only. 
     If the computer  4  needs a functionality of a peripheral unit only, the power connector  36  may be detached so as to make the connection mechanism between the cable and the computer  4  compact and lightweight. The peripheral unit  12  can work with the power supplied by the computer  4 . By removing the power connector  36 , the peripheral unit  12  may be used simply as a peripheral unit and may be connected to an other computer independently. Further, the peripheral unit can be connected to a computer which has a peripheral input connector only. 
       FIG. 10  illustrates an oblique perspective schematic view of a power adapter  8 , a cable  33  and a computer  4  according to a fifth exemplary embodiment of the present disclosure. The cable  33  may be the similar cable of the third exemplary embodiment as shown in  FIG. 6B . The power adapter  8  includes a power unit  300  and a peripheral unit  12  which are integrated. The power unit  300  includes a branch unit  20 . Moreover, the cable  30  shown in  FIG. 6B  may be employed. 
     Some examples of power adapters having a peripheral unit according to the present disclosure are as follows: 
     [1] A power adapter having an USB hub or an USB extension connector (with no controller); 
     [2] A power adapter having an Ethernet hub (IEEE 802.3) or an Ethernet extension connector (with no controller); 
     [3] A power adapter having an IEEE 1394 hub or an IEEE 1394 extension connector (with no controller); 
     [4] A power adapter having a magnetic hard disk drive (HDD), or a magnetic floppy disk drive (FDD), an optical media drive (CD-ROM/CD-RW/DVD-ROM etc.); 
     [5] A power adapter having a media card reader to read any of various media, for example, SD card, multimedia card, memory-stick, smart-media, smart-card, xD picture-card, compact-flash, ATA-interface PC card and micro-drive; 
     [6] A power adapter having a controller using serial ATA interface; 
     [7] A power adapter having a controller using PCI (peripheral component interface) Express interface; 
     [8] A power adapter having a controller using serial (RS-232C) interface; and 
     [9] A power adapter having a controller using parallel (printer, IEEE (institute of electrical and electronics engineers) 1284) interface. 
     Some examples of cables in which a data transmission line and power supply lines are integrated are as follows: 
     [10] A power supply line to the computer integrated with an USB interface data transmission line; 
     [11] A power supply line to the computer integrated with an USB interface data transmission line and a power supply line to an USB peripheral unit; 
     [12] A power supply line to the computer integrated with an IEEE 1394 interface data transmission line; 
     [13] A power supply line to the computer integrated with an IEEE 1394 interface data transmission line and a power supply line to an IEEE 1394 peripheral unit; 
     [14] A power supply line to the computer integrated with an ATA interface data transmission line; 
     [15] A power supply line to the computer integrated with an ATA interface data transmission line and a power supply line to an ATA peripheral unit; 
     [16] A power supply line to the computer integrated with a PCI Express interface data transmission line; 
     [17] A power supply line to the computer integrated with a PCI Express interface data transmission line and a power supply line to a PCI Express peripheral unit; 
     [18] A power supply line to the computer integrated with a serial (RS-232C) interface data transmission line; 
     [19] A power supply line to the computer integrated with a serial (RS-232C) interface data transmission line and a power supply line to a serial (RS-232C) peripheral unit; 
     [20] A power supply line to the computer integrated with a parallel (printer, IEEE 1284) interface data transmission line; 
     [21] A power supply line to the computer integrated with a parallel (printer, IEEE 1284) interface data transmission line and a power supply line to a parallel (printer, IEEE 1284) peripheral unit; 
     [22] A power supply line to the computer integrated with an Ethernet (IEEE 802.3) interface data transmission line; and 
     [23] A power supply line to the computer integrated with an Ethernet (IEEE 802.3) interface data transmission line and a power supply line to an Ethernet (IEEE 802.3) peripheral unit. 
       FIG. 11  illustrates an oblique perspective schematic view of a compact computer system which uses two computers  41  and  42 , a power unit  300 , a peripheral unit  312  and the pipes  24 ,  26  and  32  according to a sixth exemplary embodiment of the present disclosure. The power unit  300  of  FIG. 11  includes a peripheral connecting connector  22  through which the peripheral unit  312  is connected to the power unit  300 . In  FIG. 11 , the peripheral unit  312  is separated from the power unit  300 . 
     Initially, a first power pipe  26 , a data pipe  24  and a second power pipe  32  are integrated and are included in a cable  33 . The first power pipe  26  includes a power supply line  16  which supplies power from the power unit  300  to the computer  42 . The data pipe  24  includes a data transmission line  14  which transmits signals between the peripheral connecting connector  22  and the computer  41 . The second power pipe  32  includes a power supply line  28  which supplies power from the computer  41  to the peripheral unit  312 . 
     The first power pipe  26 , the data pipe  24  and the second power pipe  32  are configured to be detached from the cable  33 . In  FIG. 11 , the first power pipe  26  is separated from the data pipe  24  and the second power pipe  32 . The power unit  300  is connected to the computer  42  by the first power pipe  26  which is separated from the cable  33 . The peripheral unit  312  is connected to the computer  41  by the data pipe  24  and the second power pipe  32 . The computer  41  supplies power to the peripheral unit  312  and communicates with the peripheral unit  312 . 
       FIGS. 12A to 13B  illustrate oblique perspective schematic views of compact computer systems having computers  84  and  94 , power adapters  88  and  98 , peripheral units  12  and cables  86  and  96 , respectively, according to a seventh exemplary embodiment of the present disclosure. In the first to sixth embodiments, the lines in the cable are physically separated and are used as the power supply lines and as the data transmission line, respectively. However, in the seventh exemplary embodiment, a power signal and a data signal will be multiplexed and demultiplexed so as to be transferred through one line. 
       FIG. 12A  illustrates the power adapter  88  and the cable  86 . The power adapter  88  includes the peripheral unit  12  and a power unit  80  having a multiplexing-demultiplexing circuit  46 . The multiplexing-demultiplexing circuit  46  multiplexes and demultiplexes a power signal from the power unit  80  to the computer  84  with a data signal between the peripheral unit  12  and the computer  84 . Namely, the multiplexing-demultiplexing circuit  46  multiplexes and demultiplexes the power signal from a power supply circuit  21  arranged in the power unit  80  with the data signal. As a result, it is possible to supply power from the power adapter  88  to the computer  84  and to transfer the data signal between the computer  84  and the peripheral unit  12 . 
       FIG. 12B  illustrates the computer  84  and the cable  86 . The computer  84  includes a multiplexing-demultiplexing circuit  48  which multiplexes and demultiplexes a power signal from the power unit  80  to the computer  84  with a data signal between the peripheral unit  12  and the computer  84 . Namely, the multiplexing-demultiplexing circuit  48  multiplexes and demultiplexes the power signal to a main power supply circuit  23  with the data signal. As a result, it is possible to supply power from the power adapter  88  to the computer  84  and to transfer the data signal between the computer  84  and the peripheral unit  12 . The power adapter  88  of  FIG. 12A  and the computer  84  of  FIG. 12B  perform complementary functions at the respective sides and work as a pair of equipments. 
       FIG. 13A  illustrates the power adapter  98  and the cable  96 . The power adapter  98  includes a peripheral unit  12  and a power unit  90  having a multiplexing-demultiplexing circuit  52 . The multiplexing-demultiplexing circuit  52  multiplexes and demultiplexes a power signal from the computer  94  to the peripheral unit  12  with a data signal between the peripheral unit  12  and the computer  94 . As a result, it is possible to supply power from the computer  94  to the peripheral unit  12  and to transfer data between the computer  94  and the peripheral unit  12 . 
       FIG. 13B  illustrates the computer  94  and the cable  96 . The computer  94  includes a multiplexing-demultiplexing circuit  54  which multiplexes and demultiplexes a power signal from a power supply circuit  51  to the peripheral unit  12  with a data signal between the peripheral unit  12  and the computer  94 . As a result, it is possible to supply power from the computer  94  to the peripheral unit  12  and to transfer data between the computer  94  and the peripheral unit  12 . The power adapter  98  of  FIG. 13A  and the computer  94  of  FIG. 13B  perform complementary functions at the respective sides and work as a pair of equipments. 
       FIG. 14  illustrates schematically an example of a compact computer system based on the combination of the power adapters of  FIGS. 12A and 13A  and the computers of  FIGS. 12B and 13B . Computer  404  supplies DC power to peripheral unit  412  arranged in power adapter  408 . The peripheral unit  412  and the computer  404  communicate with data signals A and B. 
     The peripheral unit  412  includes first and second processing circuits  62  and  64 . The first and the second processing circuit  62  and  64  process the data signals A and B, respectively. Further, the peripheral unit  412  includes a power circuit  56  which inputs DC power supplied from the computer  404 . 
     The power unit  410  includes a power supply circuit  21  which supplies DC power to the computer  404 . Further, the power unit  410  includes first and second multiplexing-demultiplexing circuit  52  and  46 . The first multiplexing-demultiplexing circuit  52  multiplexes and demultiplexes a DC power signal from the computer  404  to the peripheral unit  412  with the data signal A. The second multiplexing-demultiplexing circuit  46  multiplexes and demultiplexes a DC power signal from the power unit  410  to the computer  404  with the data signal B. 
     The computer  404  includes a power circuit  23  and a power supply circuit  51 . A DC power from the power adapter  408  is input to the power circuit  23 . The power supply circuit  51  supplies DC power to the peripheral unit  412  arranged in the power adapter  408 . 
     Further, the computer  404  includes third and fourth processing circuits  58  and  60 . The third and fourth processing circuits  58  and  60  process the data signals A and B, respectively, during data transmission to the peripheral unit  412 . Furthermore, the computer  404  includes third and fourth multiplexing-demultiplexing circuits  54  and  48 . The third multiplexing-demultiplexing circuit  54  multiplexes and demultiplexes a DC power signal from the computer  404  to the peripheral unit  412  with a data signal A. The fourth multiplexing-demultiplexing circuit  48  multiplexes and demultiplexes a DC power signal from the power unit  410  to the computer  404  with a data signal B. 
     The first to fourth multiplexing-demultiplexing circuits  52 ,  46 ,  54  and  48  include inductors  52   i ,  46   i ,  54   i  and  48   i  and capacitors  52   c ,  46   c ,  54   c  and  48   c  as shown in  FIG. 14 . The inductor  52   i ,  46   i ,  54   i  and  48   i  multiplexes and demultiplexes a DC power signals from the power adapter  408  to the computer  404  and a DC power signals from the computer  404  to the peripheral unit  412  with the data signals A and B. 
     The capacitor  52   c ,  46   c ,  54   c  and  48   c  multiplexes and demultiplexes the data signals A and B having a predetermined frequency with the DC power signal from the power adapter  408  to the computer  404  and the DC power signal from the computer  404  to the peripheral unit  412 . 
     The operation of the power adapter  408  and the computer  404  will be described. At the first multiplexing-demultiplexing circuit  52 , the power unit  410  multiplexes the DC power signal to the peripheral unit  412  through the inductor  52   i  with the data signal A through the capacitor  52   c . The DC power signal is output from the power circuit  51  arranged in the computer  404 . The data signal A is output from the peripheral unit  412 . 
     At the second multiplexing-demultiplexing circuit  46 , the power unit  410  multiplexes the DC power signal to the computer  404  through the inductor  46   i  with the data signal B through the capacitor  46   c . The DC power signal is output from the power circuit  21  arranged in the power unit  410 . The data signal B is output from the peripheral unit  412 . 
     It is possible to output a multiplexed power signal to the peripheral unit  412  with the data signal A to the computer  404  through the cable  406 . Further, it is possible to output a multiplexed power signal to the computer  404  with the data signal B through the cable  406 . 
     At the first multiplexing-demultiplexing circuit  52 , the power unit  410  demultiplexes the DC power signal to the peripheral unit  412  through the inductor  52   i  with the data signal A through the capacitor  52   c . The DC power signal is output from the power circuit  51  arranged in the computer  404 . The data signal A is output from the computer  404 . 
     At the second multiplexing-demultiplexing circuit  46 , the power unit  410  demultiplexes the DC power signal to the computer  404  through the inductor  46   i  with the data signal B through the capacitor  46   c . The DC power signal is output from the power circuit  21  located in the power unit  410 . The data signal B is output from the computer  404 . 
     It is possible to input signals, the demultiplexed power signal to the peripheral unit  412 , the demultiplexed data signal A and the demultiplexed data signal B to the peripheral unit  412 . 
     At the third multiplexing-demultiplexing circuit  54 , the computer  404  multiplexes the DC power signal to the peripheral unit  412  through the inductor  54   i  with the data signal A through the capacitor  54   c . The DC power signal is output from the power circuit  51  arranged in the computer  404 . The data signal A is output from the computer  404 . 
     At the fourth multiplexing-demultiplexing circuit  48 , the computer  404  multiplexes the DC power signal to the computer  404  through the inductor  48   i  with the data signal B through the capacitor  48   c . The DC power signal is output from the power circuit  21  arranged in the power unit  410 . The data signal B is output from the computer  404 . 
     It is possible to output a multiplexed power signal to the peripheral unit  412  with the data signal A to the peripheral unit  412  through the cable  406 . Further, it is possible to output a multiplexed power signal to the peripheral unit  412  with the data signal B. 
     At the third multiplexing-demultiplexing circuit  54 , the computer  404  demultiplexes the DC power signal to the peripheral unit  412  through the inductor  54   i  with the data signal A through the capacitor  54   c . The DC power signal is output from the power circuit  51  arranged in the computer  404 . The data signal A is output from the peripheral unit  412 . 
     At the fourth multiplexing-demultiplexing circuit  48 , the computer  404  demultiplexes the DC power signal to the computer  404  through the inductor  48   i  with the data signal B through the capacitor  48   c . The DC power signal is output from the power circuit  21  arranged in the power unit  410 . The data signal B is output from the peripheral unit  412 . 
     It is possible to input the power signal to the computer  404  to the power circuit  23  and to input the demultiplexed data signals A and B to the third and fourth processing circuits  58  and  60 . 
     The power is successfully supplied from the power adapter  408  to the computer  404  by multiplexing the data signal A with the power signal to the peripheral unit  412  and the data signal B with the power signal to the computer  404 . Further, the power is successfully supplied from the computer  404  to the peripheral unit  412 . As a result, the computer  404  and the peripheral unit  412  can perform a data transformation successfully with the data signals A and B. 
       FIG. 15  illustrates an oblique perspective schematic view of another example of the power adapter  508  according to the seventh exemplary embodiment of the present disclosure. The power adapter  508  of  FIG. 15  includes a power multiplexing circuit  554 . The power multiplexing circuit  554  multiplexes a power signal to the peripheral unit  12  arranged in the power adapter  508  from a peripheral power supply circuit (not shown) arranged in the computer  4  with a power signal to the peripheral unit  12  from a peripheral power supply circuit  556  arranged in the power unit  510 . 
     If one of the peripheral power supply circuits becomes unstable, the other peripheral power supply circuit may supply a necessary power to the peripheral unit  12  so as to maintain the power to the peripheral unit  12  stably. 
       FIG. 16  illustrates an oblique perspective schematic view of another example of the power adapter  608  according to the seventh exemplary embodiment of the present disclosure, showing a more detailed configuration. The power adapter  608  of  FIG. 16  includes a power multiplexing circuit  654 . The power multiplexing circuit  654  multiplexes a power signal to the peripheral unit  12  arranged in the power adapter  608  from a peripheral power supply circuit (not shown) arranged in the computer  4  with a power signal to the peripheral unit  12  from a peripheral power supply circuit  556  arranged in the power unit  610 . 
     The power multiplexing circuit  654  includes two diodes. All cathodes of the diodes are connected together so that necessary power is supplied. A power supply line from a power supply circuit  656  arranged in the power unit  610  to the peripheral unit  12  and a power supply line from the computer  4  to the peripheral unit  12  are connected to the anodes of the diodes, respectively. Then, the power is appropriately supplied to the peripheral unit  12 . 
     If a plurality of power sources are connected to the anodes and even if one of the power sources is reduced to less than a predetermined value, the sufficient power may be supplied from the other power source. Further, if a total of the power sources satisfies a predetermined value and even if all the power sources do not have enough power to a predetermined value, a sufficient power may be supplied. The above discussion of the seventh exemplary embodiment is also applicable to the fifth exemplary embodiment. 
     Numerous additional modifications and variations are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the disclosure of this patent specification may be practiced otherwise than as specifically described herein. For example, elements and/or features of different illustrative embodiments and examples may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims. 
     This patent specification is based on Japanese patent application, No. 2005-272066 filed on Sep. 20, 2005 in the Japan Patent Office, the entire contents of which are incorporated by reference herein.