For LCD TV technology solutions TFT Display Module

Based on the above reasons, the response time of LCD TV must be compensation (RTC) overdrive circuit module, in order to slow the optical response of the liquid crystal display to provide compensation. This response time compensation circuit module provided in the timing controller (TCON) within the digital video stream is responsible for the interception, then each pixel of the previous instruction with a grayscale gradation command to compare the latest, and then from a lookup table (LUT) select another preset gradation. The lookup table previously written an alternate gray value is selected through experiments in order to enhance the brightness of the tail section of the frame to the target value. If the new gray level gray scale than the previous one more shallow, the system will issue an order requiring the first to provide a lighter gray level. If the new darker gray levels, the system will first issue a grayscale depth than this instruction.
Liquid crystal display monitors and notebook systems and structures used in 192x64 lcd V technology can not meet the stringent requirements (see Figure 1). Multi-branch structure of differential bus transmission lines using different digital video data to the column driver, but this structure is difficult to cope with the heavy workload of the LCD TV. For example, the transmission signal, the signal waveform must remain perfectly to a television to transmit data at higher speeds. However, due to the signal transmission line is longer, with a larger screen TV, using the column driver will more branches, so the data transmission rate would be difficult to meet the requirements. To solve these problems, some companies are developing cascade solutions. The advantage of this approach is the use of conventional bus connector end of the column driver, after the data is buffered and then transferred to the next column driver. Such a bus into the traditional point to point transmission mode, the advantage of a higher signal integrity, but the drawback is that you want to add more column driver input / output terminal and associated circuitry. Cascade structure using the re-transformation of the bus signal integrity can be improved though, but still can not meet the other requirements, such as more accurate grayscale, contrast, brightness enhancement, improved color management, and to add other more advanced features.
The first and most important is for the use of a resistor string DAC (RDAC) and column driver conventional structure, the cost-effective to provide on the basis of each color 10 gray is a very difficult challenge. All along, the only notebook system monitors and displays it using RDAC general structural design. The advantage of this structure is that the digital gray-scale data is transmitted through the differential transmission bus to the column drivers. By mapping the column driver will send the relevant value to the serial resistor string voltage on one of the nodes. According to the original design of the column drivers, each node voltages are set at a specified level, and to ensure that the set voltage can be adjusted to the brightness of the graphic lcd 128x64 monitor can be matched with a gray-scale levels . In other words, RDAC responsible not only for implementation of digital-analog conversion function, but also for implementation of the inverse gamma conversion function, which can be obtained by mapping ensures that the liquid crystal display with a supply voltage to each of the gray-scale brightness of the display as required.
RDAC on 64 gray levels (6) environment quickly perform both functions. But with 256 gray levels (8 bits) of the system, due to the increase of gray level, so the column driver 256 to the two electrodes voltage to one end of the transmission from the chip to the other end, with each of the output terminal need a circuit for decoding and pick and choose a suitable voltage, so the column driver die area will take up most of the overall die area. If the gray level increased to 1024 (10), and assuming other conditions remain unchanged, the die area occupied is too great, the whole design can not play its due role.