This application claims the priority benefit of Taiwan application serial no. 100125601, filed on Jul. 20, 2011. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
1. Field of the Invention
The invention relates to a display apparatus and more particularly to a display panel driving apparatus, an operation method thereof, and a source driver thereof.
2. Description of Related Art
In a conventional display panel driving apparatus, the data/control signal transmission between the timing controller and the source driver is a one-way transmission; that is, from the timing controller to the source driver. The timing controller frequently transmits a large amount of display data to the source driver. In the transmission of the display data from the timing controller to the source driver, various types of interference, for example, electromagnetic interference (EMI) can alter the display data. When receiving the erroneous display data, the source driver drives the display panel with the erroneous driving signal. However, the conventional source driver fails to determine whether the display data received from the timing controller are correct or not.
The invention is directed to a display panel driving apparatus, an operation method thereof, and a source driver thereof. The source driver checks a display data provided from a timing controller to prevent writing an erroneous source driving signal into a display panel.
An embodiment is directed to a display panel driving apparatus including a timing controller and a source driver. The timing controller outputs a display data and an error-check data. The source driver is coupled to the timing controller. The source driver generates a source driving signal for driving a display panel in accordance with the display data and checks the display data in accordance with the error-check data.
An embodiment is directed to a method of operating a display panel driving circuit. The method includes: transmitting a display data and an error-check data from a timing controller to a source driver; generating a source driving signal used to drive a display panel with the source driver in accordance with the display data; and checking the display data with the source driver in accordance with the error-check data.
An embodiment is directed to a source driver including a plurality of channels and an error detector. The channels each generates a source driving signal used to drive a display panel in accordance with a display data output by a timing controller. The error detector checks the display data of the channels in accordance with an error-check data output by the timing controller.
In light of the foregoing, the source driver of the embodiment receives the display data and the error-check data from the timing controller. The source driver checks the display data in accordance with the error-check data to prevent writing the erroneous source driving signal in to the display panel.
In order to make the aforementioned and other features and advantages of the invention more comprehensible, several embodiments accompanied with figures are described in detail below.
The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention.
The invention can be applied in driving apparatuses of any types of displays. For example,
Referring to
The source drivers 121-124 are coupled between the timing controller 110 and the display panel 10. After the source drivers 121-124 receive a horizontal start signal STH provided by the timing controller 110, the horizontal start signal STH undergoes a successive transition in accordance with a timing of a source clock signal CK in the source drivers 121-124. The timing controller 110 outputs a plurality of line data (display data) to a data line bus DAT sequentially in series. The source drivers 121-124 can thus obtain the display data from the data line bus DAT. In the present embodiment, the data line bus DAT is exemplified as a bus satisfying the specification of mini low voltage differential signaling (mini-LVDS), for purpose of illustration.
A horizontal blanking period and a reset period are present between two adjacent line data. Since the source drivers 121-124 are connected in parallel at the data line bus DAT, each of a plurality of line data transmission periods is divided into four sub-periods for transmitting the display data of one of the source drivers respectively. For instance, referring to
Other than the display data, the timing controller 110 in the present embodiment also transmits the error-check data in the display data to the source drivers 121-124 through the data line bus DAT. After the display data of a source driver are received, this source driver then continues to receive the corresponding error-check data. For example, referring to
The error-check data can be a complement of the display data, a complement of a total sum of the display data, a total sum of the display data, or other error checking and correction (ECC) codes. For instance, the sub-period 211 corresponds to the first line data (display data) of the source driver 121, such that the error-check data CS1 are 2's complement of a total sum of the first line data of the source driver 121. The source driver 121 checks whether a sum value of a total sum of the error-check data CS1 and the display data equals to 0 to determine whether the display data are erroneous. Or, for example, the error-check data CS1 are a total sum of the first line data of the source driver 121. The source driver 121 cumulates the display data (the first line data) to obtain a cumulative value and compares the cumulative value and the error-check data CS1 to determine whether the display data (the first line data) are erroneous.
The source drivers 121-124 check the corresponding display data in accordance with the error-check data (i.e. the error-check data CS1-CS4) respectively. When any one of the source drivers 121-124 detects an error in the display data, the source driver feeds an error message back to the timing controller 110 through a feedback bus FB. When any one of the source drivers 121-124 feeds the error message back to the timing controller 110, the timing controller 110 transmits the output enable signal OE in the disable state (i.e. logic 0) to a gate drivers 131 and 132 through the control bus, so that the gate drivers 131 and 132 do not drive one of (or several of) a plurality of corresponding gate lines in the display panel 10.
For instance, referring to
In other words, when the gate drivers 131 and 132 receive the output enable signal OE in the disable state (i.e. logic 0) through the control bus, the gate drivers 131 and 132 do not turn on the pixels on the aforementioned corresponding gate lines. Therefore, when any one of the source drivers 121-124 detects an error in the display data, the erroneous display data are not written into the pixels of the display panel 10. The source drivers 121-124 have the ability of detecting errors. The display panel driving apparatus shown in
On the other hand, each of the channels 310-330 generates a source driving signal used to drive the display panel 10 in accordance with the display data output by the timing controller 110. In the present embodiment, each of the channels 310-330 of the source driver 121 includes a sample register, a hold register, a digital-to-analog converter (DAC), and an output buffer. Take the channel 310 as an example, the channel 310 includes a sample register 311, a hold register 312, a digital-to-analog converter 313, and an output buffer 314. The implementation of other channels 320-330 can be referred to relevant descriptions of the channel 310. According to a trigger timing of the shift register 350, the sample register 311 records the display data output by the timing controller 110 through the data line bus DAT and the sample register 360 records the error-check data output by the timing controller 110 through the data line bus DAT. The hold register 312 responds to the latching signal LD of the timing controller 110 to determine whether or not to latch the display data output by the sample register 311. The digital-to-analog converter 313 converts a digital display data output by the hold register 312 into an analog source driving signal. Here, the polarity control signal POL determines whether the source driving signal output by the digital-to-analog converter 313 has positive polarity or negative polarity. The source driving signal output by the digital-to-analog converter 313 can be transmitted to the display panel 10 through the output buffer 314.
For example, in the present embodiment, the error-check data provided by the sample register 360 can be 2's complement. Therefore, if the display data of the channels 310-330 are correct, then all output bits (not including carry bits) of the full adder circuit 341 are “0”. Consequently, the error-check circuit 342 can check whether the output bits of the full adder circuit 341 are all “0”. The error-check circuit 342 can be an OR gate, where each of a plurality of input ends of the OR gate receives one of the output bits of the full adder circuit 341 respectively, and an output end of the OR gate connects to the feedback bus FB. When all of the output bits of the full adder circuit 341 are “0”, the display data received by the channels 310-330 are then correct, and the error-check circuit 342 does not raise the feedback bus FB to high logic “H”. When any one of the bits in all of the output bits in the full adder circuit 341 is “1”, then the display data received by the channels 310-330 are abnormal. When the display data received by the channels 310-330 are erroneous, the error-check circuit 342 raises the feedback bus FB to high logic “H”, so that the timing controller 110 can disable the output of the gate drivers 131 and 132 to prevent the driving of the corresponding scan lines in the display panel 10. Thus, even though the source driver 121 outputs the erroneous display data, since the corresponding scan line is not driven and the pixels are not turned on, the erroneous display data are not displayed on the display panel 10. Accordingly, all of the pixels in the corresponding scan lines maintain the display data of the last frame.
For example, in other embodiments, the error-check data provided by the sample register 360 can be 1's complement. Therefore, if the display data of the channels 310-330 are correct, then the output bits (not including carry bits) of the full adder circuit 341 are all “1”. The error-check circuit 342 can be an NAND gate, where each of a plurality of input ends of the NAND gate receives one of the output bits of the full adder circuit 341 respectively, and an output end of the NAND gate connects to the feedback bus FB. Accordingly, the error-check circuit 342 can determine whether the display data received by the channels 310-330 is incorrect in accordance with the output of the full adder circuit 341. The error-check circuit 342 can then feed the error message back to the timing controller 110 through the feedback bus FB.
Referring to
When the error detector 340 of the source driver 121 determines the display data of the channels 310-330 to be correct, the control circuit 610 transmits the latching signal LD to the hold registers of the channels 310-330 (for example, the hold register 312) as the control signal LD′. When the error detector 340 of the source driver 121 detects an error in the display data of the channels 310-330, the control circuit 610 stops the output of the control signal LD′ in accordance with the error message of the feedback bus FB. Since the latching signal LD is masked and fails to trigger the hold registers of the channels 310-330, the erroneous display data is not written into the hold registers, such that the hold registers maintain the display data of the last scan line. Accordingly, the source driver 121 depicted in
In other embodiments, the control circuit 610 further connects to a plurality of output buffers of the channels 310-330 (for example, the output buffer 314). When the error detector 340 identifies the display data of the channels 310-330 to be correct, the control circuit 610 transmits the control signal LD′ and enables the output buffers of the channels 310-330. When the error detector 340 detects an error in the display data of the channels 310-330, the control circuit 610 stops the output of the control signal LD′ in accordance with the error message of the feedback bus FB. The latching signal LD is masked, such that the output buffers of the channels 310-330 are disabled. In other words, when the display data of the channels 310-330 are erroneous, the source driver 121 stops outputting the source driving signal to the display panel 10 so as to prevent the writing of erroneous source driving signal (display data) into the display panel 10. Further, when the display data of the channels 310-330 are erroneous, the power consumption can be reduced since the output buffers of the channels 310-330 are disabled.
The control circuit 610 can be a controlled switch. A control terminal of the controlled switch is connected to the error detector 340 through the feedback bus FB. A first terminal of the controlled switch is connected to the timing switch 110 to receive the latching signal LD. A second terminal of the controlled switch is connected to the hold registers of the channels 310-330 to provide the control signal LD′.
Other than the display data, the source drivers 121-124 in the present embodiment can receive the error-check data CS1, CS2, CS3, and CS4 from the display data DAT1-DAT4 respectively. The source drivers 121-124 check the corresponding display data in accordance with the error-check data CS1-CS4 respectively. When any one of the source drivers 121-124 detects an error in any one of the display data DAT1-DAT4, the source driver feeds an error message back to the timing controller 810 through a feedback bus FB. When any one of the source drivers 121-124 feeds the error message back to the timing controller 810, the timing controller 810 can send the output enable signal OE in the disable state (i.e. logic 0) to a gate drivers 131 and 132 through the control bus, so that the gate drivers 131 and 132 do not drive one (or several) of a plurality of corresponding gate lines in the display panel 10.
For instance, referring to
In the embodiments aforementioned, the source drivers 121-124 adopt the feedback bus FB as the transmission interface when feeding the error message to the timing controller 110 (or 810). In other embodiments, the feedback bus FB can be omitted and the error message can be fed back to the timing controller 110 through other conventional buses. For example, referring to
For instance, referring to
In summary, a method of operating a display panel driving circuit is illustrated herein. The method includes: sending the display data and the error-check data from the timing controller to the source drivers 121-124; generating a source driving signal used to drive the display panel 10 with the source drivers 121-124 in accordance with the display data; and checking the display data with the source drivers 121-124 in accordance with the error-check data.
In some of the embodiments, the timing controller 110 transmits the corresponding error-check data to the source driver after the complete transmission of the display data of all of the channels in one of the source drivers. After completing the reception of the error-check data, the source driver checks the display data of the channels in accordance with the error-check data and feeds the checking result back to the timing controller 110. It should be noted that in other embodiments, the timing controller 110 can transmit the error-check data to one of the source drivers and transmit the corresponding display data to all of the channels in the source driver.
In some of the embodiments, when an error is detected in the display data, one of the source drivers 121-124 feeds the error message back to the timing controller 110. When the source drivers 121-124 feed the error message back to the timing controller 110, an output enable signal is transmitted from the timing controller 110 to the gate drivers 131 and 132. When the gate driver 131 and 132 receive the output enable signal in the disable state (i.e. logic 0), the gate drivers 131 and 132 do not drive a corresponding gate line in the display panel 10. In other embodiments, when detecting an error in the display data, the source drivers 121-124 stop outputting the source driving signal to the display panel 10.
In some of the embodiments, the step of checking the display data includes: summing the error-check data and the display data to obtain a sum value; and checking whether the sum value equals to 0 to determine whether the display data is erroneous. In some of the embodiments, the step of checking the display data includes: cumulating the display data to obtain a cumulative value; and comparing the cumulative value and the error-check data to determine whether the display data is erroneous.
The source drivers 121-124 in the embodiments receive the display data and the error-check data from the timing controller 110. The source drivers 121-124 check the display data in accordance with the error-check data to prevent writing the erroneous source driving signal into the display panel 10.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
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100125601 | Jul 2011 | TW | national |