CN103065574B - display driver - Google Patents

Abstract

A display driving apparatus includes an image data transmission interface, a frame buffer memory, and an overdrive processor. The image data transmission interface transmits image data. The frame buffer memory stores image data. The overdrive processor is coupled to the image data transmission interface to receive the current image data transmitted by the image data transmission interface, and coupled to the frame buffer memory to receive the previous image data stored in the frame buffer memory. The overdrive processor generates a display driving signal according to the current image data and the previous image data in a dynamic display mode.

Description

display driver

technical field

The present invention relates to a display driving device, and in particular to a display driving device with overdrive capability and a display device using the display driving device.

Background technique

In known display driving devices, in order to improve the display effect of dynamic images, a so-called overdriving technique is often adopted. The so-called overdrive technology is to use the way of excessively increasing (or reducing) the driving voltage to make The liquid crystal corresponding to the pixel can rotate more quickly, so that the gray scale value presented by the pixel can quickly reach the desired displayed color and brightness.

When implementing such an overdrive technique, it is known to configure two frame buffer memories in the display driver. The first framebuffer memory is used to provide new (current) image data. And another frame buffer memory temporarily stores the image data provided from the first frame buffer memory, so as to exclusively output old (previous) image data. The display driving device of the known technology calculates the gray scale change state of each pixel in the display image through the processor for the new and old image data in the two frame buffer memories, and thereby knows the required value of each pixel in the display image. The voltage value of the applied overdrive voltage. Typically, a single framebuffer must be able to store data for an entire frame. That is to say, a display driving device with a larger size requires a larger size of the frame buffer memory. Moreover, in order to cooperate with the implementation of the overdrive technology, the display driving device of the prior art requires a larger circuit area of the frame buffer memory, which increases the circuit cost of the display driving device.

Contents of the invention

The invention provides a display driving device, which can effectively reduce the area required by the circuit, and further reduce the production cost. In addition, the present invention also provides a display device using the display driving device.

The invention provides a display driving device, which includes an image data transmission interface, a frame buffer memory and an overdrive processor. The image data transmission interface is used to transmit image data. The frame buffer memory is coupled to the image data transmission interface for storing the image data. The overdrive processor is coupled to the image data transmission interface to receive current image data transmitted by the image data transmission interface, and coupled to the frame buffer memory to receive previous image data stored in the frame buffer memory. Overdrive the processor and generate a display driving signal according to the current image data and the previous image data in a dynamic display mode.

In an embodiment of the present invention, the above-mentioned display driving signals are provided to a plurality of source driving circuits.

In an embodiment of the present invention, the above-mentioned overdrive processor includes a look-up table and an arithmetic unit. The lookup table is coupled to the image data transmission interface and the frame buffer memory. The lookup table looks up the signal adjustment information according to the current image data and the previous image data. The arithmetic unit is coupled to the look-up table and the image data transmission interface. The arithmetic unit performs arithmetic operations on the current image data according to the signal adjustment information, so as to generate display driving signals.

In an embodiment of the present invention, the above arithmetic unit includes an adder for adding the signal adjustment information to the current image data to generate the display driving signal.

In an embodiment of the present invention, it further includes a mode selection switching circuit. The mode selection switching circuit selects whether to transmit the image data generated by the image data transmission interface to the overdrive processor according to whether the display drive device is in the dynamic display mode, and selects whether to transmit the image data stored in the frame buffer memory to the overdrive The processor or directly output as a display driving signal.

In an embodiment of the present invention, wherein the above-mentioned mode selection switching circuit does not transmit the image data generated by the image data transmission interface to the overdrive processor in the static display mode when the display driving device is in the non-dynamic display mode, And the previous image data stored in the frame buffer memory is directly output as a display driving signal.

In an embodiment of the present invention, it further includes a mode selection switching circuit, and the mode selection switching circuit includes a first output switching device and a second output switching device. The first output switching device is arranged between the arithmetic unit and the output terminal for outputting display driving signals. The first output switching device is turned on in the dynamic display mode and cut off in the static display mode. The second output switching device is arranged between the frame buffer memory and the output end. The second output switching device is cut off in the dynamic display mode and turned on in the static display mode.

In an embodiment of the present invention, the above-mentioned mode selection switching circuit further includes a first input switching device, a second input switching device and a third input switching device. The first input switching device is arranged between the image data transmission interface and the look-up table. The second input switching device is arranged between the image data transmission interface and the computing unit. The third input switching device is arranged between the frame buffer memory and the look-up table. Wherein, the first to the third input switching devices are all turned on in the dynamic display mode and cut off in the static display mode.

In an embodiment of the present invention, it further includes a controller and a mode command register. The controller is coupled to the mode selection switching circuit for generating a mode setting command. The mode command register is coupled to the controller for temporarily storing the mode setting command and transmitting a mode setting signal according to the mode setting command to indicate whether the display driving device is in a dynamic display mode or a static display mode.

The present invention also proposes a display device, which includes a display panel; and the above-mentioned display driving device, configured to generate a driving signal to drive the display panel.

Based on the above, the display driving device proposed by the present invention uses the current image data transmitted by the image data transmission interface and the previous image data stored in the frame buffer memory to directly receive the current image data and the current image data when performing the dynamic display mode. The previous image data is processed to obtain a display driving signal for image display. In this way, the current image data does not need to be temporarily stored in the buffer, which effectively reduces the memory usage of the display driving device, saves the area of the circuit, and further reduces the cost of the display driving device.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram of a display driving device according to an embodiment of the present invention.

FIG. 2 shows a detailed architecture of the overdrive processor of the embodiment of the present invention.

FIG. 3 is a schematic diagram of an implementation of an arithmetic unit according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a display driving device according to another embodiment of the present invention.

FIG. 5 is a schematic diagram of an implementation of the mode selection switching circuit of the embodiment of FIG. 4 .

[Description of main component labels]

100, 400: display drive device 110, 410: image data transmission interface

120, 420: frame buffer memory 130, 430: overdrive processor

140, 440: source drive circuit 131, 431: arithmetic unit

132, 432: lookup table 460: mode selection switching circuit

470: controller 480: mode command register

490: control circuit CDATA: current image data

PDATA: previous image data DDS: display drive signal

INFS: Signal adjustment information ADD1: Adder

MS: mode setting command DSIND: mode setting signal

OSW1, OSW2: Output switching device INSW1～INSW3: Input switching device

OT: output terminal

detailed description

Please refer to FIG. 1 , which is a schematic diagram of a display driving device 100 according to an embodiment of the present invention. The display driving device 100 is used, for example, in a display device for driving a display panel (not shown) to display images. The display driving device 100 includes an image data transmission interface 110 , a frame buffer memory 120 and an overdrive processor 130 . The display driving device 100 may further include a source driving circuit 140 . It should be noted that the source driver circuit 140 can be combined with the image data transmission interface 110 , the frame buffer memory 120 and the overdrive processor 130 to form an integrated circuit, or be disposed in another integrated circuit.

The image data transmission interface 110 , such as an RGB interface or a host (Host) interface, is coupled to the frame buffer memory 120 and the overdrive processor 130 for transmitting image data. In this embodiment, the current image data CDATA transmitted by the image data transmission interface 110 will be transmitted to the frame buffer memory 120 and the overdrive processor 130 at the same time. The frame buffer memory 120 temporarily stores the current image data CDATA first, and transmits the previously stored image data, ie, the previous image data PDATA, to the overdrive processor 130 . It should be noted that the so-called previous image data PDATA and current image data CDATA refer to older image data and newer image data among the image data transmitted by the image transmission interface 110 . In addition, since the current image data CDATA output from the image data transmission interface 110 does not need to pass through any memory or data temporary storage device, it generally meets the special specifications of the image data transmission interface 110 . In contrast, the previous image data PDATA output from the frame buffer memory 120 no longer meets the above special specification.

When the display driver 100 is in the dynamic display mode, the overdrive processor 130 will generate a display according to the current image data CDATA received directly from the image data transmission interface 110 and the previous image data PDATA provided from the frame buffer memory 120. Drive signal DDS.

The detailed operation of the overdrive processor 130 is further described below. When the display driver 100 is in the dynamic display mode, the overdrive processor 130 will compare the difference between the current image data CDATA and the previous image data PDATA, for example, by calculating the difference between the current image data CDATA and the previous image data PDATA. The gray scale value difference between pixels at the same display position is used to obtain the value of the display driving signal DDS required to drive each pixel. Taking pixel A as an example, when the grayscale value of pixel A in the current image data CDATA is equal to a relatively high grayscale value of 200, and the grayscale value of pixel A in the previous image data PDATA is equal to a relatively low grayscale value When 50, the overdrive processor 130 obtains the value of the display driving signal DDS required to drive the pixel A according to the difference (=150) of the gray scale value of the pixel A.

After the overdrive processor 130 obtains a suitable display driving signal DDS, it transmits the display driving signal DDS to the source driving circuit 140, and the source driving circuit 140 can generate a driving signal (such as a driving current or driving voltage) to drive the display panel. Here, the display driving signal DDS can be, for example, a digital signal, and the source driving circuit 140 can correspondingly generate an analog driving signal through its built-in digital-to-analog conversion circuit (not shown) to drive the display panel.

Please refer to FIG. 2 below. FIG. 2 shows a detailed architecture of the overdrive processor 130 according to an embodiment of the present invention, which can be applied to the display driving device shown in FIG. 1 . The overdrive processor 130 may include a computing unit 131 and a lookup table 132 . The computing unit 131 can be coupled to the image data transmission interface 110 , and the look-up table 132 can be coupled to the computing unit 131 , the image data transmission interface 110 and the frame buffer memory 120 . The lookup table 132 receives the current image data CDATA and the previous image data PDATA from the image data transmission interface 110 and the frame buffer memory 120 respectively, and performs a table lookup action according to the current image data CDATA and the previous image data PDATA to generate signal adjustment information INFS. In this embodiment, the lookup table 132 may be a two-dimensional lookup table, and receives the current image data CDATA and the previous image data PDATA as two inputs. And according to the input of the current image data CDATA and the previous image data PDATA as the index value, find out the value therein as the signal adjustment information INFS.

Taking the aforementioned pixel A as an example, if the grayscale value of pixel A in the current image data CDATA is the same as the grayscale value of pixel A in the previous image data PDATA, it means that pixel A does not need to be driven by overdrive , therefore, the lookup table 132 correspondingly generates the signal adjustment information INFS equal to 0. In contrast, when the grayscale value of pixel A in the current image data CDATA is very different from the grayscale value of pixel A in the previous image data PDATA, it means that the response time of pixel A needs to be accelerated, that is, a higher overdrive voltage. Therefore, the look-up table 132 corresponds to generate higher value signal adjustment information INFS. Incidentally, when the grayscale value of the pixel A in the current image data CDATA is greater than the grayscale value of the pixel A in the previous image data PDATA, the signal adjustment information INFS may be a positive value. In addition, when the grayscale value of the pixel A in the current image data CDATA is smaller than the grayscale value of the pixel A in the previous image data PDATA, the signal adjustment information INFS can also be a negative value.

In addition, the relative relationship between the signal adjustment information INFS generated in the lookup table 132 and the current image data CDATA and the previous image data PDATA can be obtained by the designer conducting experiments on the display driving device 100 . In the digitally constructed look-up table 132, if the look-up table 132 only provides the relationship between the current image data CDATA, the previous image data PDATA and the signal adjustment information INFS with limited bits, it can also be converted by interpolation. Higher resolution signal adjustment information INFS.

The arithmetic unit 131 receives the current image data CDATA and the signal adjustment information INFS, and uses the signal adjustment information INFS to adjust the current image data CDATA to obtain the display driving signal DDS.

Please refer to FIG. 3 below. FIG. 3 is a schematic diagram of an implementation of the computing unit 131 according to the embodiment of the present invention. The arithmetic unit 131 includes an adder ADD1. The adder ADD1 is coupled to the look-up table 132 and the image data transmission interface 110, and receives the signal adjustment information INFS and the current image data CDATA respectively. The adder ADD1 can add the signal adjustment information INFS and the current image data CDATA to generate a display driving signal DDS. It can be seen that, when the signal adjustment information INFS is a large positive value, the arithmetic unit 131 correspondingly generates a display driving signal DDS with a large value, so as to speed up the response speed of the corresponding pixel.

Next, please refer to FIG. 4 , which is a schematic diagram of a display driving device 400 according to another embodiment of the present invention. The display driving device 400 includes an image data transmission interface 410 , a frame buffer memory 420 , an overdrive processor 430 , a source driver circuit 440 , a mode selection switching circuit 460 , and a control circuit 490 . In other words, the main difference between the display driving device 400 and the display driving device 100 of FIG. 1 is that the former adds a mode selection switching circuit 460 and a control circuit 490 .

The image data transmission interface 410 is coupled to the frame buffer memory 420 and the mode selection switching circuit 460 . Wherein, the image data transmission interface 410 transmits the current image data CDATA to the frame buffer memory 420 and the mode selection switching circuit 460 . The frame buffer memory 420 stores the current image data CDATA and transmits the previously stored image data, that is, the previous image data PDATA, to the mode selection switching circuit 460 .

The mode selection switching circuit 460 is further coupled to the overdrive processor 430 and the mode command register 480 . The mode selection switching circuit 460 selects to transmit the current image data CDATA generated by the image data transmission interface 410 to the overdrive processor 430 according to when the display driving device 400 is in the dynamic display mode, and selects to transmit the CDATA stored in the frame buffer memory 420 The previous image data PDATA is sent to the overdrive processor 430 , and the output signal DSS1 generated by the overdrive processor 430 is used as the display driving signal DDS to be sent to the source driving circuit 440 . Alternatively, when the display driving device 400 is in the static display mode, the mode selection switching circuit 460 can also cut off the transmission path of the current image data CDATA and the previous image data PDATA to the overdrive processor 430, and directly output the previous image data PDATA to the source The pole driver 440 serves as the display driving signal DDS.

The mode selection switching circuit 460 receives the mode setting signal DSIND generated from the control circuit 490, wherein the mode setting signal indicates whether the display driving device is in the dynamic display mode or the static display mode controller 470 and the mode command temporary storage device 480. The controller 490 may include a controller 470 and a mode command register 480 . The mode setting signal DSIND can be generated by the mode setting command MS sent by the controller 470 and is temporarily stored in the mode command register 480 . Specifically, when the display driving device 400 detects that it is about to enter the static display mode or the dynamic display mode, the controller 470 correspondingly generates a mode setting command MS to the mode command register 480 . After the mode command register 480 receives the mode setting command MS, it generates a mode setting signal DSIND correspondingly, and transmits the mode setting signal DSIND to the mode selection switching circuit 460, and is used to indicate that the display driving device 400 is in the dynamic display mode. mode or static display mode.

Please note that the display driver 400 can know whether the image to be displayed is a dynamic image or a static image through user settings or by automatically detecting pixel changes between multiple consecutive frames in the image data to be displayed, and based on this It is detected that the display driving device 400 is about to enter the static display mode or the dynamic display mode. The display detection of related dynamic images or static images is a technology well known to those skilled in the art, and will not be described in detail below.

Please refer to FIG. 4 and FIG. 5 at the same time, wherein FIG. 5 shows a schematic diagram of an implementation of the mode selection switching circuit 460 in the embodiment of FIG. 4 . The mode selection switching circuit 460 includes a first output switching device OSW1 , a second output switching device OSW2 and first to third input switching devices INSW1 - INSW3 .

The first output switching device OSW1 can be disposed between the computing unit 431 of the overdrive processor 430 and the output terminal OT for outputting the display driving signal DDS. The second output switching device OSW2 can be disposed between the frame buffer memory 410 and the output terminal OT. Wherein, the on and off states of the first and second output switching devices OSW1 and OSW2 can be controlled by the mode setting signal DSIND, and when the display driving device 400 is in the dynamic display mode, the first output switching device OSW1 is turned on and the second output switching device OSW2 is turned off, and when the display driving device 400 is in the static display mode, the second output switching device OSW2 is turned on and the first output switching device OSW1 is turned off.

In addition, the first input switching device INSW1 is disposed between the image data transmission interface 410 and the look-up table 432 , and is used to switch on or off the path between the current image data CDATA and the look-up table 432 . The second output switching device INSW2 is disposed between the image data transmission interface and the computing unit 431 , and is used to switch on or off the path between the current image data CDATA and the computing unit 431 . In addition, the third input switching device INSW3 is disposed between the frame buffer memory 420 and the look-up table 432 to switch on or off the path between the previous image data PDATA and the look-up table 432 . The input switching devices INSW1˜INSW3 can all be controlled by the mode setting signal DSIND. Moreover, when the display driving device 400 is in the dynamic display mode, the input switching devices INSW1 - INSW3 are simultaneously turned off, and when the display driving device 400 is in the static display mode, the input switching devices INSW1 - INSW3 are simultaneously turned on.

That is to say, in this embodiment, when the display driving device 4000 is in the static display mode, the mode selection switching circuit 460 cuts off the transmission path of all signals transmitted to the overdrive processor 430, and directly transmits the previous image data PDATA as Display drive signal DDS. Moreover, when the display driving device 4000 is in the dynamic display mode, the mode selection switching circuit 460 turns on the transmission paths of all signals sent to the overdrive processor 430, and selects the output signal DDS1 of the overdrive processor 430 as the display drive signal DDS.

To sum up, in the above embodiments, the image data output by the image data transmission interface is directly transmitted to the overdrive processor and the frame buffer memory without passing through any temporary data storage device. Therefore, only one frame buffer memory is required, and the overdrive processor can calculate the overdrive voltage based on the previous image data provided by the frame buffer memory and the current image data provided by the image data transmission interface, and generate a display drive Signal. In this way, when displaying dynamic pictures, the display driver can effectively implement the overdrive technology to improve the display quality without increasing the cost due to the setting of additional frame buffer memory, effectively improving the competitiveness of the product .

Although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims (11)

1. A display driving device, comprising: An image data transmission interface for transmitting image data; a frame buffer memory, coupled to the image data transmission interface to store the image data; and An overdrive processor, coupled to the image data transmission interface and the frame buffer memory, in a dynamic display mode, the overdrive processor receives the current image data directly transmitted by the image data transmission interface without going through any a data temporary storage device, and receive the previous image data stored in the frame buffer memory, and in the dynamic display mode, generate a display driving signal according to the current image data and the previous image data; Wherein, in a static display mode, the image data stored in the frame buffer memory is directly output as the display driving signal. 2. The display driving device according to claim 1, wherein the display driving signal is provided to a plurality of source driving circuits. 3. The display driving device according to claim 1, wherein the overdrive processor comprises: a lookup table, coupled to the image data transmission interface and the frame buffer memory, to find a signal adjustment information according to the current image data and the previous image data; and An arithmetic unit, coupled to the look-up table and the image data transmission interface, performs an arithmetic operation on the current image data according to the signal adjustment information, so as to generate the display driving signal. 4. The display driving device according to claim 3, wherein the calculator comprises an adder for adding the signal adjustment information to the current image data to generate the display driving signal. 5. The display driving device according to claim 1, further comprising: A mode selection switching circuit, according to whether the display driving device is in the dynamic display mode, selects whether to transmit the image data generated by the image data transmission interface to the overdrive processor, and selects whether to transmit the image data generated by the frame buffer memory The stored image data is sent to the overdrive processor or directly output as the display driving signal. 6. The display driving device according to claim 5, wherein the mode selection switching circuit does not transmit the image data generated by the interface when the display driving device is in the static display mode other than the dynamic display mode Send to the overdrive processor, and directly output the previous image data stored in the frame buffer memory as the display drive signal. 7. The display driving device according to claim 3, further comprising a mode selection switching circuit, the mode selection switching circuit comprising: a first output switching device, arranged between the arithmetic unit and an output terminal for outputting the display driving signal, turned on in the dynamic display mode and cut off in a static display mode; and A second output switching device is arranged between the frame buffer memory and the output terminal, which is cut off in the dynamic display mode and turned on in the static display mode. 8. The display driving device according to claim 7, wherein the mode selection switching circuit further comprises: a first input switching device, arranged between the image data transmission interface and the look-up table; a second input switching device, arranged between the image data transmission interface and the computing unit; and A third input switching device is arranged between the frame buffer memory and the look-up table, wherein the first to third input switching devices are all turned on in the dynamic display mode and cut off in the static display mode. 9. The display driving device according to claim 4, further comprising: a control circuit, coupled to the mode selection switching circuit, to generate a mode setting signal to indicate whether the display driving device is in the dynamic display mode or is the static display mode. 10. The display driving device according to claim 9, wherein the control circuit comprises: a controller for generating a mode setting command; and A mode command register, coupled between the controller and the mode selection switching circuit, is used to temporarily store the mode setting command, and transmit the mode setting signal to the mode selection switching circuit according to the mode setting command . 11. A display device comprising: a display panel; and The display driving device as claimed in claim 1, used for generating a driving signal to drive the display panel.