Abstract:
An organic light emitting display device includes a display unit for displaying images in response to data signals and scan signals; a data driver including a first data driving circuit and a second data driving circuit for receiving image signals and for respectively outputting the data signals according to the images signals to corresponding areas of the display unit; a scan driver for outputting the scan signals; and a controller for driving the first data driving circuit and the second data driving circuit independently from one another.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2009-0003272, filed on Jan. 15, 2009, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a data driver and an organic light emitting display device using the same, and more particularly, to a data driver capable of reducing power consumption and an organic light emitting display device utilizing the same. 
         [0004]    2. Description of Related Art 
         [0005]    Recently, various types of flat panel display devices having reduced weight and volume as compared to cathode ray tubes have been developed. Flat panel display devices include liquid crystal display devices, field emission display devices, plasma display panels, and organic light emitting display devices, among others. 
         [0006]    Among these flat panel display devices, the organic light emitting display device displays images by utilizing organic light emitting diodes (OLEDs) that emit light through the recombination of electrons and holes. 
         [0007]    Since organic light emitting display devices have excellent color reproducibility, slimness, and other desirable properties, their application has widely increased in the markets of mobile phones, PDAs, MP3 players, and other similar devices. 
         [0008]      FIG. 1  is a schematic block diagram illustrating the structure of a conventional organic light emitting display device. 
         [0009]    Referring to  FIG. 1 , the organic light emitting display device includes a display unit  10 , a data driver  20 , a scan driver  30  and a controller  40 . 
         [0010]    A plurality of pixels  11  are arranged in the display unit  10 , and each of the pixels  11  includes an organic light emitting diode for emitting light corresponding to an amount of current. In the display unit  10  are arranged n scan lines S 1 , S 2 , . . . , Sn−1 and Sn through which scan signals are supplied in a row direction and m data lines D 1 , D 2 , . . . , Dm−1 and Dm through which data signals are supplied in a column direction. 
         [0011]    The display unit  10  is driven by a first power source and a second power source having a lower voltage level than the first power source. Accordingly, current flows through the organic light emitting diodes in accordance with the scan signals, the data signals, the first power source and the second power source, so that the display unit  10  emits light and displays an image. 
         [0012]    The data driver  20  receives a data driving control signal DCS and image signals R, G and B data supplied from the controller  40  and generates data signals. The data driver  20  is coupled to the data lines D 1 , D 2 , . . . , Dm−1 and Dm in the display unit  10  and applies the generated data signals to the display unit  10 . 
         [0013]    The scan driver  30  receives a scan driving control signal SCS supplied from the controller  40  and generates scan signals. The scan driver  30  is coupled to the scan lines S 1 , S 2 , . . . , Sn−1 and Sn and sequentially supplies scan signals to specific rows in the display unit  10 . A data signal outputted from the data driver  20  is supplied to a pixel  11  to which the scan signal is supplied, such that a voltage corresponding to the data signal is supplied to the pixel  11 . 
         [0014]    The controller  40  controls the data driver  20  and the scan driver  30 , such that an image can be expressed in the display unit  10 . 
         [0015]    When an organic light emitting display device as described above is used in, for example, a mobile phone, while in a standby mode, an image including a date, a time, or similar information may be displayed only on one area of a display unit, and no image is displayed on the other areas of the display unit. 
         [0016]    When an image is displayed on one area as described above, normal driving is also performed on the other areas where no image is displayed, so that the image in the one area can be normally displayed. That is, the data driver  20  outputs data signals to the entire display unit. Therefore, although the data driver  20  is only partially driven, the same amount of power is consumed as when the data driver  20  is normally driven. 
       SUMMARY OF THE INVENTION 
       [0017]    Accordingly, the present invention provides a data driver having reduced power consumption and an organic light emitting display device using the data driver. 
         [0018]    According to an aspect of an exemplary embodiment of the present invention, there is provided an organic light emitting display device, including a display unit for displaying images in response to data signals and scan signals; a data driver including a first data driving circuit and a second data driving circuit for receiving image signals and for respectively outputting the data signals according to the image signals to corresponding areas of the display unit; a scan driver for outputting the scan signals; and a controller for driving the first data driving circuit and the second data driving circuit independently from one another. 
         [0019]    According to an aspect of another exemplary embodiment of the present invention, there is provided a data driver including a first data driving circuit including a first shift register for generating a first shift signal, a first latch for receiving first image signals in series corresponding to the first shift signal and for outputting the first image signals in parallel, and a first D/A converter for receiving the first image signals from the first latch and for outputting data signals corresponding to the first image signals; and a second data driving circuit including a second shift register for generating a second shift signal, a second latch for receiving second image signals in series corresponding to the second shift signal and for outputting the second image signals in parallel, and a second D/A converter for receiving the second image signals from the second latch and for outputting data signals corresponding to the second image signals, wherein a controller is configured to generate the first shift signal in response to a first horizontal synchronization signal, and to generate the second shift signal in response to a second horizontal synchronization signal after the first horizontal synchronization signal is generated. 
         [0020]    In a data driver and an organic light emitting display device using the same, according to exemplary embodiments of the present invention, when a plurality of data drivers are provided and an image is displayed on only an area of a display unit, only some data drivers from the plurality of data drivers can be driven, thereby reducing power consumption. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The accompanying drawings, together with the specification, illustrate exemplary embodiments of the present invention, and together with the description, serve to explain the principles of the present invention. 
           [0022]      FIG. 1  is a schematic block diagram illustrating the structure of a conventional organic light emitting display device. 
           [0023]      FIG. 2  is a schematic block diagram illustrating the structure of an organic light emitting display device according to an embodiment of the present invention. 
           [0024]      FIG. 3  is a schematic block diagram illustrating the structure of a data driver shown in  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0025]    Hereinafter, certain exemplary embodiments according to the present invention will be described with reference to the accompanying drawings. Here, when a first element is described as being coupled to a second element, the first element may be directly coupled to the second element, or may be indirectly coupled to the second element via one or more additional elements. Further, some of the elements that are not essential to the complete understanding of the invention are omitted for clarity. Also, like reference numerals refer to like elements throughout. 
         [0026]      FIG. 2  is a schematic block diagram illustrating the structure of an organic light emitting display device according to an embodiment of the present invention. 
         [0027]    Referring to  FIG. 2 , the organic light emitting display device includes a display unit  100 , a data driver  200 , a scan driver  300  and a controller  400 . 
         [0028]    A plurality of pixels  101  are arranged in the display unit  100 , and each of the pixels  101  includes an organic light emitting diode which emits light corresponding to an amount of current. In the display unit  100  are arranged n scan lines S 1 , S 2 , . . . , Sn−1 and Sn through which scan signals are supplied in a row direction and m data lines D 1 , D 2 , . . . , Dm−1 and Dm through which data signals are supplied in a column direction. 
         [0029]    The display unit  100  is driven by receiving a first power source and a second power source having a lower voltage level than the first power source. Accordingly, current flows through the organic light emitting diodes in accordance with the scan signals, the data signals, the first power source and the second power source, so that the display unit  100  emits light for displaying an image. 
         [0030]    The data driver  200  receives a data driving control signal DCS and image signals R, G and B data from the controller  400  and generates data signals. The data driver  200  is coupled to the data lines D 1 , D 2 , . . . , Dm−1 and Dm in the display unit  100  and applies the generated data signals to the display unit  100 . The data driver  200  includes a plurality of data driving circuits  210 , . . . , and  2   k   0  and determines whether all the data driving circuits or only certain data driving circuits will be operated. 
         [0031]    If some data driving circuits of the plurality of data driving circuits are operated, a data signal is supplied to only an area (e.g., a predetermined area) of the display unit  100  so that an image is displayed on a portion of the display unit  100 . 
         [0032]    The scan driver  300  receives a scan driving control signal SCS from the controller  400  and generates scan signals. The scan driver  300  is coupled to the scan lines S 1 , S 2 , . . . , Sn−1 and Sn and supplies a scan signal to a specific row in the display unit  100 . A data signal outputted from the data driver  200  is supplied to a pixel  101  to which the scan signal is supplied so that a voltage corresponding to the data signal is supplied to the pixel  101 . 
         [0033]    The controller  400  controls an image to be expressed in the display unit  100  by supplying the image signals R, G and B data and the data driving control signal DCS to the data driver  200  and supplying the scan driving control signal SCS to the scan driver  300 . Particularly, the controller  400  determines which data driving circuits to be driven from among the plurality of data driving circuits. 
         [0034]      FIG. 3  is a block diagram showing the structure of a data driver shown in  FIG. 2 . The data driver includes a plurality of data driving circuits. For convenience of illustration, the data driver in  FIG. 3  includes two data driving circuits, represented by first and second data driving circuits  210  and  220 , respectively. 
         [0035]    Referring to  FIG. 3 , the first data driving circuit  210  includes a first shift register  211 , a first latch  212 , a first digital/analog (D/A) converter  213  and a first buffer  214 . The second data driving circuit  220  includes a second shift register  221 , a second latch  222 , a second D/A converter  223  and a second buffer  224 . 
         [0036]    The first and second data driving circuits  210  and  220  are driven by receiving first and second horizontal synchronization signals  1 Hsync and  2 Hsync, respectively. When both of the first and second data driving circuits  210  and  220  are driven, the controller  400  controls the first and second horizontal synchronization signals  1 Hsync and  2 Hsync to be supplied to the first and second data driving circuits  210  and  220 , respectively. When only the first data driving circuit  210  is driven, the controller  400  supplies the first horizontal synchronization signal  1 Hsync to the first driving circuit  210 , but does not supply the second horizontal synchronization signal  2 Hsync to the second data driving circuit  220 . When only the second data driving circuit  220  is driven, the controller  400  supplies the second horizontal synchronization signal  2 Hsync to the second driving circuit  220 , but does not supply the first horizontal synchronization signal  1 Hsync to the first data driving circuit  210 . At this time, after a time (e.g., a predetermined time) elapses from when the first horizontal synchronization signal  1 Hsync was or would have been supplied to the first data driving circuit  210 , the second horizontal synchronization signal  2 Hsync is supplied to the second data driving circuit  220 . 
         [0037]    First, if both the first and second horizontal synchronization signals  1 Hsync and  2 Hsync are respectively supplied to the first and second data driving circuits  210  and  220 , the image signals R, G and B data supplied from the controller  400  are sequentially supplied to the first and second data driving circuits  210  and  220 . 
         [0038]    That is, the serially supplied image signals R, G and B data are supplied to the first and second latches  212  and  222  by the first and second shift registers  211  and  221 , respectively. At this time, the first shift register  211  is operated by the first horizontal synchronization signal  1 Hsync, and the second shift register  221  is then operated by the second horizontal synchronization signal  2 Hsync. Accordingly, the image signals are first inputted to the first latch  212 , and the image signals are then inputted to the second latch  222 . When the input of the image signals R, G and B data to the first and second latches  212  and  222  is finished, the first and second latches  212  and  222  supply in parallel the image signals R, G and B data to the first and second D/A converters  213  and  223 , respectively. The first and second D/A converters  213  and  223  convert the image signals R, G and B data to generate data signals and then output the data signals through the first and second buffers  214  and  224 , respectively. 
         [0039]    If, for example, only the second horizontal synchronization signal  2 Hsync is supplied to the second data driving circuit  220 , the image signals R, G and B data supplied from the controller  400  is supplied to only the second data driving circuit  220 . 
         [0040]    That is, the operation of the first data driving circuit  210  is stopped, and the data signals R, G and B data are supplied to the second latch  222  in accordance with the second shift register  221  in the second data driving circuit  220 . The second latch  222  outputs in parallel the image signals R, G and B data to the second D/A converter  223 . The second D/A converter  223  converts the image signals R, G and B data to generate data signals and then outputs the data signals through the second buffer  224 . 
         [0041]    Accordingly, when the data driver  200  is partially driven, only the second data driving circuit  220  is operated or driven, thereby saving power consumption. 
         [0042]    While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is instead intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.