Abstract:
The present invention relates to a computer including a first output port, a first video signal generator to generate a first video signal having a predetermined format, a second video signal generator detachably connected to the computer and to generate a second video signal having the same format as the first video signal; and an output selector to output at least one of the first video signal and/or the second video signal through the first output port when the second video signal generator is connected to the computer. Thus, the present invention provides a computer with a low profile graphic card, which enables implementation of a dual monitor and promotes space utilization of a motherboard.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of Korean Patent Application No. 2004-0083289, filed on Oct. 18, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a computer and, more particularly, to a computer with a low profile graphic card, which enables implementation of a dual monitor and promotes improved space utilization of a motherboard.  
         [0004]     2. Description of the Related Art  
         [0005]     Generally, a computer system comprises a main body provided with a graphic card to generate a video signal, and a monitor connected to the graphic card provided in the main body to display a picture based on the video signal transmitted from the graphic card.  
         [0006]     The graphic card is classified into an internal graphic card mounted on the motherboard, and an external graphic card detachably connected to a slot on the motherboard. Generally, the internal graphic card is disabled while the external graphic card is in use, and vice versa.  
         [0007]      FIG. 1  illustrates a configuration of a conventional motherboard mounted with an internal graphic card.  
         [0008]     As illustrated therein, a motherboard  100  includes a main chipset  102  functioning as the internal graphic card to generate red, green and blue (RGB) signals, RGB signal lines  106  transmitting the RGB signals generated from the main chipset  102 , and an internal RGB port  104  receiving the RGB signals through the RGB signal lines  106  and outputting them to the monitor.  
         [0009]     Thus, the RGB signals generated by the main chipset  102  are outputted to the internal RGB port  104  through the RGB signal lines  106 .  
         [0010]     However, there is a limit to the graphic performance of the internal graphic card, so that the external graphic card is frequently used in order to compensate for the limit in the graphic performance in cases when only the internal graphic card is used.  
         [0011]     In the external graphic card, a digital video interface (DVI) port  116  and an external RGB port  118  are all provided (refer to  FIG. 2 ), or either a DVI port  144  or an RGB port (not shown) is provided (refer to  FIG. 3 )  
         [0012]     As illustrated in  FIG. 2 , the external graphic card  110  that is provided with both the DVI port  116  and the external RGB port  118  is generally used to implement a conventional dual monitor in a desktop computer. Such an external graphic card  110  includes a graphic controller  112  to generate a DVI signal and an RGB signal. The DVI port  116  and the external RGB port  118  are used to transmit the DVI signal and the RGB signal generated from the graphic controller  112 , respectively, and an accelerated graphics port (AGP) interface line  114   a  provides an AGP interface between a motherboard  120  and the external graphic card  110 .  
         [0013]     In  FIG. 2 , the motherboard  120  includes a main chipset  122  functioning as the internal graphic card to generate an RGB signal, an RGB signal line  126  to transmit the RGB signal generated by the main chipset  122 , an internal RGB port  124  to transmit the RGB signal from the RGB signal line  126  to the monitor, the AGP interface line  114   b  providing the AGP interface between the graphic controller  113  of the external graphic card  110  and the main chipset  122 , and an AGP slot  119  to which the external graphic card  110  is connected so as to connect the AGP interface line  114   b  of the motherboard  120  with an AGP interface line  114   a  of the external graphic card  110 .  
         [0014]     When the external graphic card  110  is connected to the AGP slot  119  of the motherboard  120 , the function of the internal graphic card in the main chipset  122  is disabled. Therefore, the RGB signal is not outputted through the RGB signal line  126  of the motherboard  120 , and the graphic controller  112  of the external graphic card  110  communicates with the main chipset  122  through the AGP interface lines  114   a  and  114   b . The DVI and RGB signals generated by the graphic controller  112  are outputted through the DVI port  116  and the external RGB port  118 , respectively.  
         [0015]     Thus, a monitor having an interface corresponding to the DVI port  116  and a monitor having an interface corresponding to the external RGB port  118  are connected to the DVI port  116  and the external RGB port  118 , respectively, thereby making the implementation of a dual monitor system possible.  
         [0016]     However, in the case of a widespread slim computer, there is a limit to a space of the slim computer, so that the size of the external graphic card should be decreased corresponding to the size of the main body. Thus, the external graphic card for the slim computer cannot comprise both the DVI port and the RGB port.  
         [0017]     Accordingly, the external graphic card for the slim computer generally includes either the DVI port or the RGB port. Such an external graphic card for the slim computer is generally called “low profile graphic card”.  
         [0018]      FIG. 3  illustrates connection between the external graphic card including only a DVI port  144  and the motherboard  130  in the conventional slim computer.  
         [0019]     As illustrated therein, the external graphic card  140  includes a graphic controller  142  to generate the DVI signal and the RGB signal, the DVI port  144  to transmit the DVI signal from the graphic controller  142  to the monitor, and an AGP interface line  138   a  providing an AGP interface between the motherboard  130  and the external graphic card  140 .  
         [0020]     The motherboard  130  of  FIG. 3  has the same configuration as that of  FIG. 2 , so that repetitive descriptions will be avoided as necessary.  
         [0021]     When the external graphic card  140  is connected to an AGP slot  139  of the motherboard  130 , function of the internal graphic card in the main chipset  132  is disabled. Therefore, the RGB signal is not outputted to an internal RGB port  134  through the RGB signal line  136  of the motherboard  130 , and the graphic controller  142  of the external graphic card  140  communicates with the main chipset  132  through the AGP interface lines  138   a  and  138   b . Only the DVI signal generated by the graphic controller  142  is outputted through the DVI port  144 .  
         [0022]     In this case, there is no port for the RGB signal generated by the graphic controller  142 . Therefore, in the case of the low profile graphic card  140  shown in  FIG. 3 , it is impossible to realize the dual monitor system.  
         [0023]     Further, in the case of the external graphic card  140  shown in  FIG. 3 , the internal RGB port  134  can be removed from the motherboard  130 , so that space utilization of the motherboard  130  is deteriorated.  
       SUMMARY OF THE INVENTION  
       [0024]     Accordingly, it is an aspect of the present invention to provide a computer with a low profile graphic card, which enables implementation of a dual monitor and promotes space utilization of a motherboard.  
         [0025]     The foregoing and/or other aspects of the present invention are also achieved by providing a computer including a first output port, a first video signal generator to generate a first video signal having a predetermined format, a second video signal generator detachably connected to the computer and to generate a second video signal having the same format as the first video signal, and an output selector to output either the first video signal and/or the second video signal through the first output port when the second video signal generator is connected to the computer.  
         [0026]     According to another aspect of the present invention, the computer further includes a motherboard, and an interface provided in the motherboard and to which the second video signal generator is detachably connected, wherein the first video signal generator is disabled and the output selector outputs the second video signal through the first output port when the second video signal generator is connected to the interface.  
         [0027]     According to another aspect of the present invention, the output selector includes a first path to transmit the first video signal generated from the first video signal generator to the first output port, and a second path to transmit the second video signal generated from the second video signal generator to the first output port.  
         [0028]     According to another aspect of the present invention, the second path connects the second video signal generator with the first output port via the interface.  
         [0029]     According to another aspect of the present invention, the second path is branched from the first path and connected to the second video signal generator through the interface.  
         [0030]     According to another aspect of the present invention, the computer further includes a resistor provided on the second path and having resistance of a predetermined level or less.  
         [0031]     According to another aspect of the present invention, the first and second video signals have an analog-type format.  
         [0032]     According to another aspect of the present invention, the second video signal generator further generates a third video signal different in format from the second video signal, and includes a second output port to transmit the third video signal.  
         [0033]     According to another aspect of the present invention, the third video signal has a digital-type format.  
         [0034]     According to another aspect of the present invention, the output selector includes a controller to sense whether the second video signal generator is connected to the computer, and to output the first video signal through the first output port when the second video signal generator is connected to the computer.  
         [0035]     According to another aspect of the present invention, the computer further includes a motherboard, and an interface that is provided in the motherboard, to which the second video signal generator is detachably connected, and which generates an attachment/detachment sensing signal according to whether the second video signal generator is connected to the interface, wherein the controller determines whether the second video signal generator is connected to the interface on the basis of the attachment/detachment sensing signal generated by the interface, and controls the first video signal to be outputted through the first output port when the second video signal generator is connected to the interface.  
         [0036]     The foregoing and/or other aspects of the present invention are also achieved by providing a graphic card that is detachably connected to the computer, including an output port, an interface having a plurality of signal pins for communicating with the computer, and a graphic controller that generates first and second videos signals different in format from each other on the basis of data transmitted from the computer through the interface, outputs the first video signal through the output port, and outputs the second video signal to the computer through at least some signal pins among a plurality of signal pins provided in the interface.  
         [0037]     According to another aspect of the present invention, the interface supports an AGP interface.  
         [0038]     According to another aspect of the present invention, the second video signal is outputted from the graphic controller to the computer through at least one of the signal pins among the plurality of signal pins provided in the interface except the signal pins for data communication that uses the AGP interface.  
         [0039]     According to another aspect of the present invention, the first video signal has one format of an analog-type and a digital-type, and the second video signal has the other format.  
         [0040]     Another aspect of the present invention is achieved by providing a computer method including generating a first video signal having a predetermined format and generating a second video signal having the same format as the generated first video signal, and outputting at least one of the generated first video signal and/or the generated second video signal through an output port when the generated second video signal is connected to a computer.  
         [0041]     Another aspect of the present invention is achieved by providing a method, including mounting an external graphic card to a computer, outputting a digital video interface (DVI) signal through a first port, generating a RGB signal and outputting said RGB signal through a second port; and implementing a dual monitor through said second port.  
         [0042]     Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0043]     These and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompany drawings of which:  
         [0044]      FIG. 1  illustrates a configuration of a conventional motherboard mounted with an internal graphic card;  
         [0045]      FIG. 2  illustrates connection between an external graphic card and a motherboard for a dual monitor in a conventional desktop computer;  
         [0046]      FIG. 3  illustrates connection between an external graphic card and a motherboard in a conventional slim computer;  
         [0047]      FIG. 4  illustrates connection between an external graphic card and a motherboard in a computer according to a first embodiment of the present invention;  
         [0048]      FIG. 5  illustrates an AGP slot according to the first embodiment of the present invention;  
         [0049]      FIG. 6  illustrates a specific signal line connection between the AGP slot and its peripheral circuitry according to the first embodiment of the present invention; and  
         [0050]      FIG. 7  is a control block diagram of a computer according to a second embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0051]     Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.  
         [0052]      FIG. 4  illustrates the connection between an external graphic card and a motherboard in a computer according to a first embodiment of the present invention. As shown therein, a computer according to the first embodiment of the present invention comprises a motherboard  10  having an AGP slot  24  used as an interface, and an external graphic card  30  detachably connected to the AGP slot  24  of the motherboard  10 . According to an embodiment of the present invention, the external graphic card  30  includes a low profile graphic card having, for example, only a DVI port  34 .  
         [0053]     The external graphic card  30  comprises a graphic controller  32  that is used to generate an RGB signal (hereinafter, referred to as “external RGB signal”) and a DVI signal as video signals. A DVI port  34  is used to transmit the DVI signal generated from the graphic controller  32  to a monitor. An AGP interface line  22   a  forms an AGP interface between the motherboard  10  and the graphic controller  32 , and an external RGB signal line  18   a  is used as a second path for transmitting the external RGB signal generated from the graphic controller  32 .  
         [0054]     The motherboard  10  comprises a main chipset  12  functioning as an internal graphic card that is used to generate an RGB signal (hereinafter, referred to as “internal RGB signal”) as a video signal, an internal RGB signal line  16  that is used as a first path for transmitting the internal RGB signal generated from the main chipset  12 , an internal RGB port  14  to transmit the internal RGB signal transmitted through the internal RGB signal line  16  to the monitor, and an AGP interface line  22   b  to form an AGP interface between the main chipset  12  and the graphic controller  32  of the external graphic card  30 .  
         [0055]     Further, the motherboard  10  comprises an external RGB signal line  18   b  used as the second path for transmitting the external RGB signal that is generated by the graphic controller  32  of the external graphic card  30  to the internal RGB signal line  16  through the AGP slot  24 . The AGP slot  24  connects the AGP interface line  22   b  of the motherboard  10  with the AGP interface  22   a  of the external graphic card  30 , and also connects the external RGB signal line  18   a  of the external graphic card  30  with the external RGB signal line  18   b  of the motherboard  10  when the external graphic card  30  is connected to the motherboard  10 . A resistor  20  is also connected to the external RGB signal line  18   b.    
         [0056]     In the case of the typical motherboard, the AGP slot has a plurality of surplus pins that are seldom used (refer to a mark of “X” in  FIG. 5 ).  
         [0057]     According to an embodiment of the present invention, the external RGB signal line  18   a  is provided for allowing the external RGB signal generated by the graphic controller  32  of the external graphic card  30  to be outputted through such surplus pins of the AGP slot  24 . Further, the external RGB signal line  18   b  used as the second path branched from the internal RGB signal line  16  formed on the motherboard  10  is routed for allowing the RGB signal passing through both the external RGB signal line  18   a  provided in the external graphic card  30  and the AGP slot  24  to be outputted to the internal RGB port  14  through the internal RGB signal line  16 . Thus, the main chipset  12  outputs the external RGB signal through the internal RGB port  14  when the external graphic card  30  is connected to the motherboard  10 .  
         [0058]      FIG. 6  illustrates a specific signal line connection between the AGP slot and its peripheral circuitry according to the first embodiment of the present invention.  
         [0059]     As shown therein, the graphic controller  32  is connected to the AGP slot  24  through the AGP interface lines  22   a , and the external RGB signal lines  18   a  (RED, GREEN, BLUE, HSYNC, VSYNC, DDCA_DATA, DDCA_CLK). Further, the AGP slot  24  is connected to the main chipset  12  through the AGP interface line  22   b . Also, the AGP slot  24  is connected to the internal RGB port  14  through the external RGB signal line  18   b . The external RGB signal lines  18   a  and  18   b  are connected to each other through the surplus pins  40  of the AGP slot  24 , and are routed in a branched fashion from the internal RGB signal line  16 , thereby being connected to the internal RGB port  14 .  
         [0060]     The resistor  20  connected to the external RGB signal line  18   b  is employed to prevent a stub effect from arising on the internal RGB signal line  16 . Preferably, the resistor  20  has a resistance of close to 0 Ω. Further, the resistor  20  is preferably connected to the external RGB signal line  18   b  when the external graphic card  30  is used. Otherwise, the resistor is not connected.  
         [0061]     With this configuration, when the external graphic card  30  is connected to the motherboard  10  in the computer according to an embodiment of the present invention, the video signal is transmitted as described hereinafter. When the external graphic card  30  is inserted into the AGP slot  24  of the motherboard  10 , the main chipset  12  does not function as the internal graphic card. Therefore, the internal RGB signal is not outputted through the internal RGB signal line  16  of the motherboard  10 .  
         [0062]     On the other hand, the graphic controller  32  of the external graphic card  30  communicates with the main chipset  12  by the AGP interface lines  22   a  and  22   b . Further, the DVI signal generated in the graphic controller  32  is outputted to the DVI port  34 . Also, the RGB signal generated in the graphic controller  32  is outputted to the internal RGB port  14  through both the external RGB signal lines  18   a  and  18   b  and the internal RGB signal line  16  connected with the external RGB signal lines  18   a  and  18   b.    
         [0063]     Thus, when the external graphic card  30  is mounted to the slim computer, the DVI signal is outputted through the DVI port  34  of the external graphic card  30 , and the RGB signal generated in the graphic controller  32  is outputted through the internal RGB port  14  of the motherboard  10 , thereby enabling implementation of a dual monitor and enhancing utilization by using the existing internal RGB port  14 .  
         [0064]      FIG. 7  is a control block diagram of a computer according to a second embodiment of the present invention. As illustrated therein, a computer according to the second embodiment of the present invention comprises an interface  52 , an external graphic card  50  detachably connected to the interface  52  and having a DVI port (not shown), a main chipset  54  that functions as an internal graphic card  56  for generating an internal RGB signal and as a controller  58 . The internal RGB port  60  is for outputting the internal RGB signal.  
         [0065]     The interface  52  includes an AGP slot or a peripheral component interconnect (PCI)-express slot, to which the external graphic card  50  is detachably connected. The interface  52  generates an attachment/detachment sensing signal when the external graphic card  50  is attached thereto or detached therefrom.  
         [0066]     The external graphic card  50  generates the RGB signal and the DVI signal in different formats from each other. The DVI signal is outputted through a DVI port (not shown) provided in the external graphic card  50 .  
         [0067]     The main chipset  54  generates the internal RGB signal and outputs it through the internal RGB port  60  when it is determined that the external graphic card  50  is connected to the interface  52  on the basis of the attachment/detachment sensing signal generated by the interface  52 .  
         [0068]     Thus, when the external graphic card  50  is mounted to the computer according to the second embodiment of the present invention, the DVI signal is outputted through the DVI port of the external graphic card  50 , and the RGB signal generated in the main chipset  54  is outputted through the internal RGB port  60 , thereby enabling the implementation of a dual monitor  
         [0069]     According to an embodiment of the present invention, the main chipset  12 ,  54  is used as an output selector to output the external RGB signal or the internal RGB signal through the internal RGB port  14 ,  60  when the external graphic card  30  or  50  is mounted.  
         [0070]     In the foregoing embodiment, the external graphic card includes an AGP card, but is not limited to this configuration, and the external graphic card may include a PCI express card connected to a PCI express slot.  
         [0071]     In the foregoing embodiment, the motherboard and the external graphic card are provided with the RGB port and the DVI port as an output port, respectively, but are not limited to this configuration. Alternatively, each of the motherboard and the external graphic card may be provided with one of various video output ports.  
         [0072]     Thus, when the external graphic card is mounted to the computer, the computer outputs the video signal generated from either the external graphic card or the internal graphic card through the output port provided in the motherboard, thereby enabling the implementation of the dual monitor.  
         [0073]     As described above, the present invention provides a computer with a low profile graphic card, which not only enables the implementation of a dual monitor but also promotes space utilization of a motherboard.  
         [0074]     Although a few embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.