Patent Publication Number: US-2018047323-A1

Title: Driving circuit and operating method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a driving circuit, especially to a display panel driving circuit and an operating method thereof applied to a display apparatus. 
     2. Description of the Prior Art 
     In a conventional liquid crystal display apparatus, a driving IC is usually used to receive input image data from outside and use its internal digital image processing circuit to perform data processing on the input image data and then the processed input image data is transmitted to the source driver to generate output voltage to the display panel. 
     Please refer to  FIG. 1  and  FIG. 2 .  FIG. 1  illustrates a schematic diagram of the display panel driving circuit including a frame storage in the prior art;  FIG. 2  illustrates a schematic diagram of the display panel driving circuit without frame storage in the prior art. 
     No matter the frame storage is included or not, if the same image data SIN is continuously inputted from outside, the digital processing circuit  14  of the driving circuit  1  and the digital processing circuit  24  of the driving circuit  2  should repeat the same process to generate the same processed image data and then the source driver  15  will generate the same output voltage to the display panel PL. These repeated data processing procedures will cause unnecessary power consumption, and this drawback is needed to be overcome. 
     SUMMARY OF THE INVENTION 
     Therefore, the invention provides a driving circuit and an operating method thereof to solve the above-mentioned problems. 
     An embodiment of the invention is a driving circuit. In this embodiment, the driving circuit is disposed in a display apparatus and coupled to a display panel. The driving circuit includes a data comparator, a data processor and a driver. The data comparator is used for determining whether a second row of image data is the same with a previous first row of image data, wherein if the second row of image data is the same with the first row of image data, the data comparator outputs a disable signal; if the second row of image data is different from the first row of image data, the data comparator outputs the second row of image data to replace the first row of image data. The data processor is coupled to the data comparator, wherein when the data processor receives the disable signal from the data comparator, the data processor stops operating according to the disable signal and outputs an indicating signal; when the data processor receives the second row of image data from the data comparator, the data processor processes the second row of image data to generate a second row of output image data. The driver is coupled between the data processor and the display panel, wherein when the driver receives the indicating signal from the data processor, the driver outputs a previous first row of output image data to the display panel according to the indicating signal; when the driver receives the second row of output image data from the data processor, the driver outputs the second row of output image data to the display panel to replace the first row of output image data. 
     In an embodiment, the driving circuit further includes a transmission interface and another data processor. The transmission interface is used for receiving an input image data from outside. The another data processor is coupled among the transmission interface, the data comparator and the data processor and used for performing data processing on the input image data to generate a frame of image data, wherein the frame of image data includes the first row of image data and the second row of image data. 
     In an embodiment, the driving circuit further includes a row buffer. The row buffer is coupled between the another data processor and the data processor and used for receiving and temporarily storing the first row of image data or the second row of image data. 
     In an embodiment, if there is no other row of image data previous to the first row of image data in the frame of image data, the row buffer directly transmits the first row of image data to the data processor and the data processor performs data processing on the first row of image data to generate the first row of output image data. 
     In an embodiment, two input terminals of the data comparator are coupled to an input terminal and an output terminal of the row buffer respectively, the first row of image data is previous to the second row of image data in the frame of image data, the data comparator compares the first row of image data with the second row of image data to determine whether the first row of image data is the same with the second row of image data; if the first row of image data is different from the second row of image data, the row buffer uses the second row of image data to replace the temporarily stored first row of image data. 
     In an embodiment, the driving circuit further includes a transmission interface, another data processor and a frame storage. The transmission interface is used for receiving an input image data from outside. The another data processor is coupled to the transmission interface and used for performing data processing on the input image data to generate a frame of image data, wherein the frame of image data includes the first row of image data and the second row of image data. The frame storage is coupled among the another data processor, the data comparator and the data processor and used for receiving and temporarily storing the frame of image data. 
     In an embodiment, the driving circuit further includes a row buffer. The row buffer is coupled between the frame storage and the data processor and used for receiving and temporarily storing the first row of image data or the second row of image data. 
     In an embodiment, if there is no other row of image data previous to the first row of image data in the frame of image data, the row buffer directly transmits the first row of image data to the data processor and the data processor performs data processing on the first row of image data to generate the first row of output image data. 
     In an embodiment, two input terminals of the data comparator are coupled to an input terminal and an output terminal of the row buffer respectively, the first row of image data is previous to the second row of image data in the frame of image data, the data comparator compares the first row of image data with the second row of image data to determine whether the first row of image data is the same with the second row of image data; if the first row of image data is different from the second row of image data, the row buffer uses the second row of image data to replace the temporarily stored first row of image data. 
     Another embodiment of the invention is a driving circuit operating method. In this embodiment, the driving circuit operating method is used for operating a driving circuit disposed in a display apparatus. The driving circuit is coupled to a display panel. The driving circuit includes a data comparator, a data processor and a driver. The data processor is coupled to the data comparator. The driver is coupled between the data processor and the display panel. The driving circuit operating method includes steps of: (a) using the data comparator to determine whether a second row of image data is the same with a previous first row of image data, wherein if the second row of image data is different from the first row of image data, the data comparator outputs the second row of image data to replace the first row of image data; (b) if the second row of image data is the same with the first row of image data, outputting a disable signal to control the data processor to stop operating and output an indicating signal to the driver, and the driver outputs a previous first row of output image data to the display panel according to the indicating signal; and (c) if the second row of image data is different from the first row of image data, outputting the second row of image data to the data processor to replace the previous first row of output image data, the data processor performing data processing on the second row of image data to generate a second row of output image data to the driver, and the driver outputting the second row of output image data to the display panel to replace the first row of output image data. 
     Compared to the prior art, the display panel driving circuit and operating method thereof of the invention will determine whether the current row of image data is the same with the pervious row of image data according to the input image data. If the current row of image data is the same with the pervious row of image data, the display panel driving circuit and operating method thereof of the invention will stop the data processing of the back-end digital image processing circuit and directly output the row image data stored in the data driving circuit (namely the source driver). Therefore, the unnecessary and power consumptive data processing procedures can be effectively stopped to achieve the effect of reducing digital electrical power consumption. 
     The advantage and spirit of the invention may be understood by the following detailed descriptions together with the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         FIG. 1  illustrates a schematic diagram of the display panel driving circuit including a frame storage in the prior art. 
         FIG. 2  illustrates a schematic diagram of the display panel driving circuit without frame storage in the prior art. 
         FIG. 3A  illustrates a schematic diagram of the display panel driving circuit including a frame storage in an embodiment of the invention. 
         FIG. 3B  illustrates a schematic diagram of the frame of image data SF including a plurality of rows of image data wherein the first row of image data and the second row of image data are the same. 
         FIG. 3C  illustrates a schematic diagram of the frame of image data SF including a plurality of rows of image data wherein the first row of image data and the second row of image data are different. 
         FIG. 4  illustrates a schematic diagram of the display panel driving circuit without frame storage in another embodiment of the invention. 
         FIG. 5  illustrates a schematic diagram of the driving circuit further including a row buffer in the invention. 
         FIG. 6  illustrates a flowchart of the driving circuit operating method in another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention provides a driving circuit disposed in a display apparatus and coupled to a display panel. When the driving circuit determines that the current row of image data is the same with the pervious row of image data according to the input image data, the driving circuit of the invention will stop the data processing of the back-end digital image processing circuit and directly output the row image data stored in the source driver. Therefore, the unnecessary and power consumptive data processing procedures can be effectively stopped to achieve the effect of reducing digital electrical power consumption. 
     A preferred embodiment of the invention is a display panel driving circuit. It should be noticed that the display panel driving circuit in this embodiment includes a frame storage. Please refer to  FIG. 3A .  FIG. 3A  illustrates a schematic diagram of the display panel driving circuit including a frame storage in this embodiment. 
     As shown in  FIG. 3A , the display panel driving circuit  3  coupled to the display panel PL includes a transmission interface  31 , a first data processor  32 , a frame storage  33 , a data comparator  34 , a second data processor  35  and a source driver  36 . Wherein, the transmission interface  31  is coupled to the first data processor  32 ; the first data processor  32  is coupled to the frame storage  33 ; the frame storage  33  is coupled to the data comparator  34  and the second data processor  35 ; the data comparator  34  is coupled to the second data processor  35 ; the second data processor  35  is coupled to the source driver  36 ; the source driver  36  is coupled to the display panel PL. 
     Next, the above-mentioned units of the display panel driving circuit  3  will be introduced in detail as follows. 
     The transmission interface  31  is used for receiving an input image data SIN from outside, and then the first data processor  32  will perform data processing on the input image data SIN to generate a frame of image data SF. The frame storage  33  is used for receiving the frame of image data SF from the transmission interface  31  and temporarily storing the frame of image data SF. 
     It should be noticed that, as shown in  FIG. 3B  and  FIG. 3C , the frame of image data SF at least includes multiple rows of image data including a first row of image data R 1  and a second row of image data R 2 , wherein the first row of image data R 1  is previous to the second row of image data R 2 . That is to say, the frame storage  33  will receive and temporarily store two adjacent rows of image data (namely the first row of image data R 1  and the second row of image data R 2 ) in the frame of image data SF in order. The difference between  FIG. 3B  and  FIG. 3C  is that the first row of image data R 1  and the second row of image data R 2  in  FIG. 3B  are the same, but the first row of image data R 1  and the second row of image data R 2  in  FIG. 3C  are different. 
     When the frame storage  33  receives and temporarily stores the first row of image data R 1  in the frame of image data SF, the data comparator  34  will access the first row of image data R 1  from the frame storage  33 . At this time, since there is no other image data previous to the first row of image data R 1 , the data comparator  34  fails to compare the first row of image data R 1  with other image data. Instead, the second data processor  35  will access the first row of image data R 1  from the frame storage  33  and perform data processing on the first row of image data R 1  to generate a first row of output image data R 1 ′ to the source driver  36 . Then, the source driver  36  will output the first row of output image data R 1 ′ to the display panel PL, and the display panel PL will display the first row of output image data R 1 ′. 
     When the frame storage  33  receives and temporarily stores the second row of image data R 2  in the frame of image data SF, the data comparator  34  will access the second row of image data R 2  from the frame storage  33 . At this time, the data comparator  34  can compare the current accessed second row of image data R 2  with the previous accessed first row of image data R 1  to determine whether the second row of image data R 2  is the same with the first row of image data R 1 . 
     If the data comparator  34  determines that the second row of image data R 2  is the same with the first row of image data R 1 , as shown in  FIG. 3B , the data comparator  34  will output a disable signal DIS to the second data processor  35 , and the second data processor  35  will stop operating according to the disable signal DIS and output an indicating signal K to the source driver  36 . 
     It should be noticed that since the second data processor  35  stops operating according to the disable signal DIS at this time, the second data processor  35  will neither access the second row of image data R 2  from the frame storage  33  nor perform any data processing on the second row of image data R 2 . By doing so, the invention can effectively stop the unnecessary and power consumptive data processing procedure performed in prior art to reduce the digital electrical power consumption. 
     When the source driver  36  receives the indicating signal K from the second data processor  35 , the source driver  36  will still output the first row of output image data R 1 ′ to the display panel PL instead of outputting other new output image data. 
     If the data comparator  34  determines that the second row of image data R 2  is different from the first row of image data R 1 , as shown in  FIG. 3C , the data comparator  34  will output the second row of image data R 2  to the second data processor  35  to replace the previous first row of image data R 1 . 
     When the second data processor  35  receives the second row of image data R 2 , the second data processor  35  will perform data processing on the second row of image data R 2  to generate a second row of output image data R 2 ′ to the source driver  36 . 
     When the source driver  36  receives the second row of output image data R 2 ′ from the second data processor  35 , the source driver  36  will stop outputting the first row of output image data R 1 ′ to the display panel PL. Instead, the source driver  36  will output the second row of output image data R 2 ′ to the display panel PL. 
     As to other rows of image data in the frame of image data SF, such as a third row of image data, a fourth row of image data, . . . and so on, since they are similar to the above-mentioned first row of image data R 1  and second row of image data R 2 , it is not repeated here. 
     Please refer to  FIG. 4 . In another embodiment, the display panel driving circuit  4  can also include no frame storage. As shown in  FIG. 4 , the display panel driving circuit  4  coupled to the display panel PL includes a transmission interface  41 , a first data processor  42 , a data comparator  44 , a second data processor  45  and a source driver  46 . Wherein, the transmission interface  41  is coupled to the first data processor  42 ; the first data processor  42  is coupled to the data comparator  44  and the second data processor  45 ; the data comparator  44  is coupled to the second data processor  45 ; the second data processor  45  is coupled to the source driver  46 ; the source driver  46  is coupled to the display panel PL. 
     Next, the above-mentioned units of the display panel driving circuit  4  will be introduced in detail as follows. 
     The transmission interface  41  is used for receiving an input image data SIN from outside, and then the first data processor  42  will perform data processing on the input image data SIN to generate a frame of image data SF. It should be noticed that, the frame of image data SF at least includes a first row of image data R 1  and a second row of image data R 2 , wherein the first row of image data R 1  is previous to the second row of image data R 2 . 
     When the data comparator  44  receives the first row of image data R 1  from the first data processor  42 , since there is no other image data previous to the first row of image data R 1 , the data comparator  44  fails to compare the first row of image data R 1  with other image data. Instead, the second data processor  45  will receive the first row of image data R 1  and perform data processing on the first row of image data R 1  to generate a first row of output image data R 1 ′ to the source driver  46 . Then, the source driver  46  will output the first row of output image data R 1 ′ to the display panel PL, and the display panel PL will display the first row of output image data R 1 ′. 
     When the data comparator  44  receives the second row of image data R 2  from the first data processor  42 , the data comparator  44  will compare the current accessed second row of image data R 2  with the previous accessed first row of image data R 1  to determine whether the second row of image data R 2  is the same with the first row of image data R 1 . If the data comparator  44  determines that the second row of image data R 2  is the same with the first row of image data R 1 , as shown in  FIG. 3B , the data comparator  44  will output a disable signal DIS to the second data processor  45 , and the second data processor  45  will stop operating according to the disable signal DIS and output an indicating signal K to the source driver  46 . When the source driver  46  receives the indicating signal K from the second data processor  45 , the source driver  46  will still output the first row of output image data R 1 ′ to the display panel PL according to the indicating signal K. By doing so, the invention can effectively stop the unnecessary and power consumptive data processing procedure performed in prior art to reduce the digital electrical power consumption. 
     If the data comparator  44  determines that the second row of image data R 2  is different from the first row of image data R 1 , as shown in  FIG. 3C , the data comparator  44  will output the second row of image data R 2  to the second data processor  45  to replace the previous first row of image data R 1 . When the second data processor  45  receives the second row of image data R 2  from the data comparator  44 , the second data processor  45  will perform data processing on the second row of image data R 2  to generate a second row of output image data R 2 ′ to the source driver  46 . When the source driver  46  receives the second row of output image data R 2 ′ from the second data processor  45 , the source driver  46  will stop outputting the first row of output image data R 1 ′ to the display panel PL. Instead, the source driver  46  will output the second row of output image data R 2 ′ to the display panel PL. 
     In practical applications, as shown in  FIG. 5 , the display panel driving circuit  5  can further include a row buffer LB. The row buffer LB is coupled among the first data processor  42 , the data comparator  44  and the second data processor  45  and used for receiving and temporarily storing the first row of image data R 1  or the second row of image data R 2  in the frame of image data SF in order. 
     In the frame of image data SF, since there is no other row of image data previous to the first row of image data R 1 , the row buffer LB will directly transmit the first row of image data R 1  to the second data processor  45  and the second data processor  45  will perform data processing on the first row of image data R 1  to generate the first row of output image data R 1 ′. 
     As to the data comparator  44 , two input terminals of the data comparator  44  are coupled to an input terminal and an output terminal of the row buffer LB respectively. Since the first row of image data R 1  is previous to the second row of image data R 2  in the frame of image data SF, the data comparator  44  will compare the first row of image data R 1  with the second row of image data R 2  to determine whether the first row of image data R 1  is the same with the second row of image data R 2 . 
     If the first row of image data R 1  is different from the second row of image data R 2 , as shown in  FIG. 3C , the row buffer LB will use the second row of image data R 2  to replace the temporarily stored first row of image data R 1 . 
     If the first row of image data R 1  is the same with the second row of image data R 2 , as shown in  FIG. 3B , the row buffer LB will maintain the temporarily stored first row of image data R 1  unchanged. 
     Another embodiment of the invention is a driving circuit operating method. In this embodiment, the driving circuit operating method is used for operating a driving circuit disposed in a display apparatus. The driving circuit is coupled to a display panel. The driving circuit includes a data comparator, a data processor and a driver. The data processor is coupled to the data comparator. The driver is coupled between the data processor and the display panel. 
     Please refer to  FIG. 6 .  FIG. 6  illustrates a flowchart of the driving circuit operating method in this embodiment. As shown in  FIG. 6 , the driving circuit operating method includes the following steps (S 10 )˜(S 14 ) of: 
     (S 10 ) using the data comparator to determine whether a second row of image data is the same with a previous first row of image data, wherein if the second row of image data is different from the first row of image data, the data comparator outputs the second row of image data to replace the first row of image data; 
     (S 12 ) if the second row of image data is the same with the first row of image data, the method outputs a disable signal to control the data processor to stop operating and to output an indicating signal to the driver, and the driver outputs a previous first row of output image data to the display panel according to the indicating signal; and 
     (S 14 ) if the second row of image data is different from the first row of image data, the method outputs the second row of image data to the data processor to replace the previous first row of output image data, the data processor performs data processing on the second row of image data to generate a second row of output image data to the driver, and the driver outputs the second row of output image data to the display panel to replace the first row of output image data. 
     Compared to the prior art, the display panel driving circuit and operating method thereof of the invention will determine whether the current row of image data is the same with the pervious row of image data according to the input image data. If the current row of image data is the same with the pervious row of image data, the display panel driving circuit and operating method thereof of the invention will stop the data processing of the back-end digital image processing circuit and directly output the row image data stored in the data driving circuit (namely the source driver). Therefore, the unnecessary and power consumptive data processing procedures can be effectively stopped to achieve the effect of reducing digital electrical power consumption. 
     With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.