Abstract:
A cradle device includes: a magnetic sensor that outputs a detection signal that indicates an intensity of a magnetic field of a magnet provided in an electronic apparatus for detecting that the magnet is within a threshold distance; a power connection terminal that is connectable to a power source; a switching unit that switches to turn on and off the power supplied through the power connection terminal in accordance with the detection signal; and an apparatus connection terminal that is connectable to the electronic apparatus and supplies power supplied through the power connection terminal and the switching unit to the electronic apparatus.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2007-338765, filed on Dec. 28, 2007, the entire content of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    One embodiment of the present invention relates to a cradle device for extending a function of an electronic apparatus and the electronic apparatus connectable to the cradle device. 
         [0004]    2. Description of the Related Art 
         [0005]    A portable electronic apparatus such as a portable personal computer and a PDA (Personal Digital Assistant) is configured so as to use a device (hereinafter, referred to as a cradle device) having an extension function for extending a function useable by a user, while maintaining a portability of the electronic apparatus. 
         [0006]    The electronic apparatus and the cradle device have respective connection terminals to be electrically connected to each other. The respective connection terminals provided in the electronic apparatus and the cradle device are disposed so as to be fitted to each other when the electronic apparatus is placed on a placement portion provided in the cradle device, for example. 
         [0007]    When the electronic apparatus is connected to the cradle device, a user charges a battery incorporated with the electronic apparatus using power supplied from the cradle device or can operate the electronic apparatus using an input device such as a mouse connected to the cradle device through the USB terminal. 
         [0008]    On the other hand, when the electronic apparatus is not connected to the cradle device, it is desirable that power consumption is reduced or the power supply from a commercial power source or the like to the cradle device is blocked in order to prevent a short-circuited accident caused due to contact of a metal piece with the connection terminal of the cradle device. 
         [0009]    Conventionally, there is disclosed in JP-A-5-066858 a technique for controlling the power supply depending on a connection state of the electronic apparatus and the cradle device. 
         [0010]    The cradle device disclosed in the document, JP-A-5-066858, includes a unit for supplying power to the electronic apparatus, a unit for recognizing a state where the electronic apparatus is connected, and a unit for blocking the power supply to the electronic apparatus when it is recognized that the electronic apparatus has not been connected. Accordingly, when the electronic apparatus is not connected, the power supply to the electronic apparatus is configured to be blocked. 
         [0011]    Recently, a smaller portable electronic apparatus has been developed and a small electronic apparatus with an A5 size or a smaller size can be seen. Accordingly, it is necessary for the small electronic apparatus to have a smaller connection terminal to be connected to the cradle device. 
         [0012]    However, the known technique has a problem in that the connection terminal becomes necessarily large since a signal (recognition signal) for recognizing the connection with or the disconnection from the electronic apparatus has to be transmitted through the connection terminal in order for the cradle device to recognize the connection with or the disconnection from the electronic apparatus. For that reason, the known technique is not appropriate for the small electronic apparatus with the A5 size or the smaller size. 
       SUMMARY 
       [0013]    One of objects of the present invention is to provide a cradle device capable of easily determining whether the cradle device and an electronic apparatus are connected to each other without using a connection terminal and the electronic apparatus to be connected to the cradle device. 
         [0014]    According to a first aspect of the present invention, there is provided a cradle device for extending a function of an electronic apparatus, the cradle device including: a magnetic sensor that outputs a detection signal that indicates an intensity of a magnetic field of a magnet provided in the electronic apparatus for detecting that the magnet is within a threshold distance when the intensity of the magnetic field is equal to or more than a threshold intensity; a power connection terminal that is connectable to a power source to receive power supplied from the power source; a switching unit that switches to turn on and off the power supplied through the power connection terminal in accordance with the detection signal output from the magnetic sensor; and an apparatus connection terminal that is connectable to the electronic apparatus and supplies power supplied through the power connection terminal and the switching unit to the electronic apparatus, wherein the switching unit switches to turn on the power supplied through the power connection terminal when the detection signal indicating that the intensity of the magnetic field is equal to or more than the threshold intensity is received, and wherein the switching unit switches to turn off the power supplied through the power connection terminal when the detection signal indicating that the intensity of the magnetic field is less than the threshold intensity is received. 
         [0015]    According to a second aspect of the present invention, there is provided a cradle device for extending a function of an electronic apparatus, the cradle device including: a magnetic sensor that outputs a detection signal that indicates an intensity of a magnetic field of a magnet provided in the electronic apparatus for detecting that the magnet is within a threshold distance when the intensity of the magnetic field is equal to or more than a threshold intensity; a power connection terminal that is connectable to a power source to receive power supplied from the power source; and a first switching unit that switches to turn on and off the power supplied through the power connection terminal in accordance with the detection signal output from the magnetic sensor; an apparatus connection terminal that is connectable to the electronic apparatus and supplies power supplied through the power connection terminal and the switching unit to the electronic apparatus; an external device connection terminal that is electrically connected to the switching unit in parallel with the apparatus connection terminal for connecting an external apparatus; a second switching unit that is provided between the apparatus connection terminal and a connection point of the apparatus connection terminal and the external device connection terminal; and a switch control unit that controls the first switching unit and the second switching unit to turn on and off based on one of a first setting and a second setting when the detection signal indicating that the intensity of the magnetic field is less than the threshold intensity is received, wherein the first setting is to turn off the power from the power source to the apparatus connection terminal and the external device connection terminal by turning off the first switching unit and the second switching unit, and wherein the second setting is to turn off the power supply to the apparatus connection terminal and to turn on the power supply to the external device connection terminal by turning on the first switching unit and turning off the second switching unit. 
         [0016]    According to a third aspect of the present invention, there is provided an electronic apparatus connectable to a cradle device, wherein the cradle device includes: a magnetic sensor that outputs a detection signal that indicates an intensity of a magnetic field of a magnet provided in the electronic apparatus for detecting that the magnet is within a threshold distance when the intensity of the magnetic field is equal to or more than a threshold intensity; a power connection terminal that is connectable to a power source to receive power supplied from the power source; a switching unit that switches to turn on and off the power supplied through the power connection terminal in accordance with the detection signal output from the magnetic sensor; and an apparatus connection terminal that is connectable to the electronic apparatus and supplies power supplied through the power connection terminal and the switching unit to the electronic apparatus, wherein the switching unit switches to turn on the power supplied through the power connection terminal when the detection signal indicating that the intensity of the magnetic field is equal to or more than the threshold intensity is received, wherein the switching unit switches to turn off the power supplied through the power connection terminal when the detection signal indicating that the intensity of the magnetic field is less than the threshold intensity is received, wherein the electronic apparatus comprises the magnet that is disposed at a position where the magnetic sensor of the cradle device detects the magnetic field having the intensity equal to or more than the threshold intensity when the electronic apparatus is connected to the cradle device. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0017]    A general configuration that implements the various feature of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. 
           [0018]      FIG. 1  is a diagram illustrating an overall configuration of a cradle device and an electronic apparatus connected to the cradle device according to a first embodiment of the invention. 
           [0019]      FIG. 2  is a front perspective view illustrating the cradle device. 
           [0020]      FIG. 3  is a front view illustrating the electronic apparatus. 
           [0021]      FIG. 4  is a front view illustrating an example where the electronic apparatus is connected to the cradle device  20 . 
           [0022]      FIG. 5  is a rear perspective view illustrating the cradle device. 
           [0023]      FIG. 6  is a schematic block diagram illustrating an example of the inside configuration of the cradle device according to the first embodiment. 
           [0024]      FIG. 7  is a diagram for explaining a relationship between a threshold distance within which a magnetic sensor can sense a magnet and a threshold protrusion length of an apparatus connection terminal. 
           [0025]      FIG. 8  is a schematic block diagram illustrating an example of the inner configuration of a cradle device according to a second embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    Embodiments of an information processing apparatus of the invention will be discussed with reference to the accompanying drawings. 
         [0027]    A cradle device and an electronic apparatus according to embodiments of the invention will be described with reference to the accompanying drawings. 
         [0028]      FIG. 1  is a diagram illustrating an overall configuration of a cradle device and an electronic apparatus connected to the cradle device according to a first embodiment of the invention.  FIG. 1  shows that the electronic apparatus is connected to the cradle device. 
         [0029]    An electronic apparatus  10  includes an LCD  11 , which is a display unit of a display input unit formed in the center portion of a case upper surface, and a power button  12  which is formed in the case upper surface. 
         [0030]    The display input unit includes the LCD  11  as the display unit and a pen tablet unit or a touch panel as an input unit. 
         [0031]    The cradle device  20  is a device for extending functions which can be used by a user while maintaining portability of the electronic apparatus  10 . The cradle device  20  includes a base support portion  21  for containing various circuits and a body support portion  22  for supporting the electronic apparatus  10  connected to the cradle device  20 . 
         [0032]      FIG. 2  is a front perspective view illustrating the cradle device  20 . As shown in  FIG. 2 , the cradle device  20  further includes a magnetic sensor  23  disposed inside the base support portion  21  and an apparatus connection terminal  24  to be electrically connected to the electronic apparatus  10 . 
         [0033]      FIG. 3  is a front view illustrating the electronic apparatus  10 . The electronic apparatus  10  further includes a magnet  13 , which is disposed near the magnetic sensor  23  of the cradle device  20  when the electronic apparatus  10  is connected to the cradle device  20 , and an extension connection terminal  14 , which can be electrically connected to the apparatus connection terminal  24  of the cradle device  20 . 
         [0034]      FIG. 4  is a front view illustrating an example where the electronic apparatus  10  has been connected to the cradle device  20 . 
         [0035]    As shown in  FIG. 4 , the magnet  13  and the magnetic sensor  23  are disposed in the electronic apparatus  10  and the cradle device  20 , respectively, so as to be close to each other when the extension connection terminal  14  of the electronic apparatus  10  is connected to the apparatus connection terminal  24  of the cradle device  20 . 
         [0036]    More specifically, the magnetic sensor  23  is configured so as to sense that the magnet  13  provided in the electronic apparatus  10  is within a threshold distance by detecting a magnetic field having an intensity equal to or more than a threshold intensity. In addition, the magnet  13  is disposed at a position from which the magnetic sensor  23  can detect the magnetic field having the intensity equal to or more than the threshold intensity when the electronic apparatus  10  is connected to the cradle device  20 . 
         [0037]    One of the apparatus connection terminal  24  and the extension connection terminal  14  has a protruding shape with a threshold length from a case of the one the cradle device  20  and the electronic apparatus  10 , and the other of the apparatus connection terminal  24  and the extension connection terminal  14  has a concave shape for fitting to the one of the apparatus connection terminal  24  and the extension connection terminal  14 . In this embodiment, the apparatus connection terminal  24  provided in the cradle device  20  has the protruding shape with the threshold length from the case, and the extension connection terminal  14  provided in the electronic apparatus  10  has the concave shape for fitting to the apparatus connection terminal  24 . 
         [0038]      FIG. 5  is a rear perspective view illustrating the cradle device  20 . As shown in  FIG. 5 , a power connection terminal  25 , which is connected to a commercial power source to receive power from a power source, and an external device connection terminal group  26  are provided on the rear surface of the base support  21  of the cradle device  20 . The external device connection terminal group  26  includes a USB (Universal Serial Bus) type-A receptacle  27  and a USB type-B receptacle  28 . 
         [0039]    When the electronic apparatus  10  is connected to the cradle device  20  (see  FIG. 4 ), a user charges a battery incorporated with the electronic apparatus  10  using the power supplied from the cradle device  20  or can operate the electronic apparatus  10  using an input device such as a mouse connected to the cradle device  20  through the USB type-A receptacle  27 . 
         [0040]    The USB type-A receptacle  27  includes a power supply line as well as a signal line. Accordingly, the power can be supplied to the external apparatus connected to the cradle device  20  through the power supply line of the USB type-A receptacle  27 . The power supplied through the USB type-A receptacle  27  has a voltage value of 5 V, for example. 
         [0041]      FIG. 6  is a schematic block diagram illustrating an example of the inside configuration of the cradle device  20 . 
         [0042]    As shown in  FIG. 6 , the cradle device  20  further includes a voltage drop unit  30  and a switching unit  31  of which one end is connected to the power connection terminal  25 . The other end of the switching unit  31  is connected to the apparatus connection terminal  24  and the USB type-A receptacle  27 . 
         [0043]      FIG. 6  shows an example where an alternating-current voltage supplied from the commercial power source is changed into a direct current voltage of 15 V to be supplied to the power connection terminal  25  by an AC adapter or the like and the direct current voltage of 15 V is supplied to the apparatus connection terminal  24 . 
         [0044]    When the voltage to be supplied through the USB type-A receptacle  27  is 5 V, the direct current voltage of 15 V supplied through the power connection terminal  25  drops to 5 V by the voltage drop unit  30  to be supplied to the USB type-A receptacle  27 , as shown in  FIG. 6 . 
         [0045]    An output signal of the magnetic sensor  23  is input to the switching unit  31 . The switching unit  31  shorts connection when it receives an output signal indicating the detection of the magnetic field having the intensity equal to or more than the threshold intensity from the magnetic sensor  23 . Alternatively, the switching unit  31  opens the connection when it receives an output signal indicating the detection of the magnetic field having the intensity less than the threshold intensity from the magnetic sensor  23 . 
         [0046]    Next, an example of an operation of the cradle device  20  and the electronic apparatus  10  to be connected to the cradle device  20  according to this embodiment will be described. 
         [0047]    The magnetic sensor  23  detects that the magnet  13  provided in the electronic apparatus  10  is within the threshold distance by detecting the magnetic field having the intensity equal to or more than the threshold intensity and outputs the signal indicating the detection of the magnetic field to the switching unit  31  when the electronic apparatus  10  is connected to the cradle device  20 . The switching unit  31  receives the signal indicating the detection of the magnetic field having the intensity equal to or more than the threshold intensity from the magnetic sensor  23  and shorts the connection. 
         [0048]    As a result, when the power connection terminal  25  and the apparatus connection terminal  24  are electrically connected to each other, the direct current voltage of 15 V is supplied to the apparatus connection terminal  24 . Moreover, when the power connection terminal  25  and the USB type-A receptacle  27  are electrically connected to each other, the direct current voltage of 5 V is supplied to the USB type-A receptacle  27 . 
         [0049]    On the other hand, when the electronic apparatus  10  is disconnected from the cradle device  20 , the magnetic sensor  23  outputs a signal indicating the detection of the magnetic field having the intensity less than the threshold intensity. The switching unit  31  receives the signal indicating the detection of the magnetic field having the intensity less than the threshold intensity from the magnetic sensor  23  to open the connection. 
         [0050]    As a result, when the connection between the power connection terminal  25  and the apparatus connection terminal  24  are opened, the supply of the direct current voltage to the apparatus connection terminal  24  is blocked. Moreover, when the connection between the power connection terminal  25  and the USB type-A receptacle  27  is opened, the supply of the direct current voltage to the USB type-A receptacle  27  is also blocked. 
         [0051]    In the cradle device  20  and the electronic apparatus  10  to be connected to the cradle device  20  according to this embodiment, it is possible to easily determine whether the cradle device  20  and the electronic apparatus  10  are connected to each other, by using the magnetic sensor  23  and the magnetic  13  without using the connection terminals (the apparatus connection terminal  24  and the extension connection terminal  14 ). Accordingly, it is not necessary to install a signal line for recognizing connection with the connection terminals (the apparatus connection terminal  24  and the extension connection terminal  14 ). Moreover, it is possible to miniaturize the connection terminals (the apparatus connection terminal  24  and the extension connection terminal  14 ). 
         [0052]    As a result, in the cradle device  20  and the electronic apparatus  10  to be connected to the cradle device  20  according to this embodiment, it is possible to easily determine whether the cradle device  20  and the electronic apparatus  10  are connected to each other while miniaturizing the electronic apparatus  10  and the cradle device  20 . 
         [0053]    In the cradle device  20  and the electronic apparatus  10  to be connected to the cradle device  20  according to this embodiment, the magnetic sensor  23  and the magnet  13  are installed in the cradle device  20  and the electronic apparatus  10 , respectively, and the magnetic sensor  23  detects the magnetic field generated by the magnet  13 . With such a configuration, whether the cradle device  20  and the electronic apparatus  10  are connected to each other is determined. Accordingly, it is possible to easily sense one another by adjusting a relative position of the magnetic sensor  23  and the magnet  13 . 
         [0054]    For example, if a magnet  13  of another electronic apparatus  10  mounted in the another electronic apparatus  10  having the same extension connection terminal  14  is mounted at a position different from the position where the extension connection terminal  14  is mounted in the electronic apparatus  10 , the cradle device  20  does not supply power to the apparatus connection terminal  24  even though the another electronic apparatus  10  is connected. Accordingly, it is possible to beforehand prevent an accident occurring when the different electronic apparatus  10  is erroneously connected. 
         [0055]    The reason for blocking the power supply to the apparatus connection terminal  24  of the cradle device  20  when the electronic apparatus  10  is connected to the cradle device  20  is to reduce standby electricity of the cradle device  20  and prevent a short-circuited accident caused due to the contact of a metal piece with the exposed apparatus connection terminal  24 . 
         [0056]    In order to prevent the short-circuited accident caused due to the contact of the metal piece with the exposed apparatus connection terminal  24 , it is desirable that the power supply to the apparatus connection terminal  24  is surely blocked before the apparatus connection terminal  24  is exposed. 
         [0057]      FIG. 7  is a diagram for explaining a relationship between a threshold distance within which the magnetic sensor  23  can sense the magnet  13  and a protruding threshold length of the apparatus connection terminal  24 . 
         [0058]    In order to surely block the power supply to the apparatus connection terminal  24  before the apparatus connection terminal  24  is exposed, it is necessary to adjust the protruding threshold length of the apparatus connection terminal  24 . Specifically, the protruding threshold length of the apparatus connection terminal  24  is set to a length within which the magnetic sensor  23  can sense that the magnet  13  is not present before the fitting of the apparatus connection terminal  24  and the extension connection terminal  14  is completely released. 
         [0059]    Next, a cradle device  20 A and an electronic apparatus  10  to be connected to the cradle device  20 A according to a second embodiment of the invention will be described. 
         [0060]    The cradle device  20 A according to the second embodiment is different from the cradle device  20  according to the first embodiment in that power supply to an apparatus connection terminal  24  is blocked, but the power supply to a USB type-A receptacle  27  is allowed, when the electronic apparatus  10  is not connected to the cradle device  20 A. The same Reference Numerals are given to the same constituent elements and the description is omitted since the rest configuration and the operation of the cradle device  20 A is not substantially different from those of the cradle device  20  and the electronic apparatus  10  connected to the cradle device  20  shown in  FIG. 1 . 
         [0061]      FIG. 8  is a schematic block diagram illustrating an example of the inner configuration of a cradle device  20 A according to a second embodiment. 
         [0062]    As shown in  FIG. 8 , the cradle device  20 A further includes another switching unit  32 , a switch control unit  33 , and an operational unit  34 . 
         [0063]    The another switching unit  32  is connected between the apparatus connection terminal  24  and a connection point of the USB type-A receptacle  27  and the apparatus connection terminal  24 . 
         [0064]    The switch control unit  33  controls shorting and opening of the switching unit  31  and the another switching unit  32  on the basis of one of first setting and second setting when the switch control unit  33  receives an output signal indicating detection of a magnetic field having an intensity less than a threshold intensity from a magnetic sensor. The switch control unit  33  controls the switching unit  31  and the another switching unit  32  so as to be shorted when the switch control unit  33  receives an output signal indicating detection of a magnetic field having an intensity equal to or more than a threshold intensity from the magnetic sensor. 
         [0065]    The first setting is to block the power supply to the apparatus connection terminal  24  and the USB type-A receptacle  27  by opening the connection between the switching unit  31  and the power connection terminal  25  and the connection between the another switching unit  32  and the power connection terminal  25 . In addition, the second setting is to allow the power supply to the USB type-A receptacle  27 , but block the power supply to the apparatus connection terminal  24  by shorting the switching unit  31  and opening the another switching unit  32 . 
         [0066]    The operational unit  34  supplies the switch control unit  33  with information indicating which setting is used to perform the controlling between the first setting and the second setting. For example, the operational unit  34  may be provided as a slide switch on the side surface of a base support portion  21 . If the slide switch is used, the slide switch is configured so as to be positioned in a first state and a second state. When the slide switch is positioned in the first state, the information indicating that the first setting is necessary is supplied to the switch control unit  33 . Alternatively, when the slide switch is positioned in the second state, the information indicating that the second setting is necessary is supplied to the switch control unit  33 . 
         [0067]    The cradle device  20 A and the electronic apparatus  10  to be connected to the cradle device  20 A according to this embodiment have the same advantage as that of the cradle device  20  and the electronic apparatus  10  to be connected to the cradle device  20  according to the first embodiment. 
         [0068]    In the cradle device  20 A and the electronic apparatus  10  to be connected to the cradle device  20 A according to this embodiment, it is possible to prevent a short-circuited accident caused due to contact of a metal piece with the apparatus connection terminal  24  by blocking the power supply to the apparatus connection terminal  24  when the electronic apparatus  10  is not connected, for example. Moreover, it is possible to continue the power supply to an external apparatus which is connected to the USB type-A receptacle  27  to be electrically charged or the like. 
         [0069]    As described above, in a cradle device and an electronic apparatus to be connected to the cradle device according to the present invention, it is possible to easily determine whether the cradle device and the electronic apparatus are connected to each other. 
         [0070]    The present invention is not limited to the above-described embodiments, but may be modified into various forms without departing from the gist of the invention by modifying the constituent elements. For example, the switch control unit may be realized as a processor. Moreover, the plural constituent elements in the above-described embodiments may be appropriately combined to form various aspects of the invention. For example, several constituent elements may be omitted from the entire constituent elements in the above-described embodiments. Furthermore, the constituent elements in the different embodiments may be appropriately combined.