1、附录 A Low Power 260k Color VGA TFT LCD One-chip Driver IC Abstract - In this study, we present a 260k Color VGA TFT one-chip LCD Driver IC that consumes low power in module.To reduce power consumption and a chip size, we used a sub-pixel rendering and a data compression algorithm.The currently, in or
2、der to display the bigger and higher resolution, the imbedded graphic SRAM size becomes bigger.But, because the mass-production size has limitation, the driver IC of a VGA resolution is normally two or three chip solution.The study is the first time made VGA one-chip IC in world. The IC is implement
3、ed in a 0.15um process. I. INTRODUCTION Current telecommunication technology has improved amazingly.These improvements have revitalized hand-held modules and increased multi-media services.To use a hand- held module for a longer time, each chip needs to become smaller and consume less power.The size
4、 of display equipment has become bigger and the resolution higher. Due to this, power consumption of display equipment has also become higher. Power reduction for display equipment has become a very important issue. The multi-color display panel is implemented by arranging an RGB (red, green, blue)
5、color filter.The color rectangular panel is supplied by row-direct voltage and column-direct voltage. The difference of the two direct voltages is the driving voltage of the pixels. This method is called multiplex addressing. The LCD driver IC generates and supplies the voltage level. This paper pre
6、sents a 260 k-color TFT LCD one-chip driver module that consists of a gate driver and source driver. The gate driver generates the driving voltage of column direction and common voltage. The gate driving voltage is of two types: a selected level and a non-selected level. The level of these voltages
7、is determined by the characteristics of each panel. When one gate line is selected, the source IC drives data voltage levels that are valued by decoding stored data. The different voltage of the gates selected level and sources data level determine the display material arrangement. With a higher col
8、or resolution, the embedded memory capacity needs to be bigger in the LCD driver IC. The power consumption of the merged memory also becomes a very important issue. With a higher resolution and bigger panel， a bigger embedded memory size is necessary. Because of this, shrinking the RAM size is a dom
9、inant factor in the chip size of a driver IC. In this paper, section II presents the architecture of graphic driving IC. Section III discusses the algorithm of sub-pixel rendering. Section IV discusses the image data compression. Section V, the implemented sample is compared in VGA driver IC. The ch
10、ip samples are implemented in a 0.15 um process and tested in manual test board and probing machine (T6371 Advantest). II. STRUCTURE OF THE DRIVER IC Generally, the driver IC is composed of a logic part, an analog part, and a memory part. The analog part is composed of the LCD driver, DCDC converter
11、, voltage divider, and oscillator. The oscillator circuit generates a clock for display. The DCDC converter circuit receives the generated clock and generates the highest/lowest voltage level. The voltage divider circuit divides between the highest and lowest level. The driver block supplies the var
12、ious voltages to the panel.The 260k TFT one-chip IC is composed of a logic, a embedded memory, an oscillator, a DCDC converter block, a source/gate driver block and a common voltage generating block. The logic part is composed of an MPU interface block, memory-addressing block, and timing control bl
13、ock. The MPU interface block interfaces between the driver IC and the external MPU.The memory-addressing block receives the decoded signal in the MPU interface and generates the memory address.The resister array is included in the gray scale generator.The implemented driving IC has three types of ad
14、justment: a gradient adjustment, an amplitude adjustment, and a fine adjustment. The timing control block generates a signal, which controls the display panel. The embedded memory is the same as normal memory. The output data from memory is transferred to the source driver. The driver has the sub-pi
15、xel rendering and compressing process in order to decrease the embedded memory size. A data form external chip is received by the system interface block, the internal format converted data of a processed in system interface is sent to GMA block (Input gamma block), the pre-SPR formatted data is sent
16、 to SPR (Sub-Pixel Rendering) block. The SPR block calculates the one pixel with around pixel data and then output processed a sub-pixel data. Because the sub-pixel data has the around pixel information, the stored data can be lower data quantity.The sub-pixel is sent to compressing block and the co
17、mpressed output is stored in the embedded memory. The stored data is decompressed and output to the source driver in the display clock. The display data in the source driver block is not same with normal RGB strips type. The data type is called the Pentile Matrix type. The Pentile Matrix type can be
18、 had original visibility in a human eye.The sub-pixel rendering and the compression processing can be had lower memory size and low power consumption than the normal processing. III. SUB-PIXEL RENDERING The sub-pixel rendering algorithm in out chip is used a Clair Voyantes algorithm 3, 4. The presen
19、t application relates to the conversion of graphics data formats from one form to another, and specifically to the conversion of (red-green-blue) RGB graphics to improved color pixel arrangements used in displays. The present state of the art of color single plane imaging matrix, for flat panel disp
20、lays, use the RGB color triad or a single color in a vertical stripe as shown in prior art Figure. 1. The system takes advantage of the Von Bezold color blending effect by separating the three colors and placing equal spatial frequency weight on each color. However, these panels are a poor match to
21、human vision. Graphic rendering techniques have been developed to improve the image quality of prior art panels.Benzchawel,etal.in3 teaches how to reduce an image of a larger size down to a smaller panel. In so doing, Benzchawel, et al. teach how to improve the image quality using a technique now kn
22、own in the art as sub-pixel rendering. More recently Hill, etal. in 4 teach how to improve text quality by reducing a virtual image of text, one character at a time, using the very same sub-pixel rendering technique. The above prior art pay inadequate attention to how human vision operates. The prio
23、r arts reconstruction of the image by the display device is poorly matched to human vision. The dominant model used in sampling, or generating,and then storing the image for these displays is the RGB pixel ( or three-color pixel element), in which the red, green,and blue values are on an orthogonal
24、equal spatial resolution grid and are co-incident. One of the consequences of using this image format is that it is a poor match both to the real image reconstruction panel,with its spaced apart, non-coincident, color emitters, and the human vision.This effectively results in redundant, or wasted, i
25、nformation in the image. Full color perception is produced in the eye by three-color receptor nerve cell types called cones. The three types are sensitive to different wave lengths of light: long, medium, and short (red, green, and blue, respectively). The relative density of the three wavelengths d
26、iffers significantly form one another. There are slightly more red receptors than green receptors. There are very few blue receptors compared to red or green receptors. In addition to the color receptors, there are relative wavelength insensitive receptors called rods that contribute to monochrome n
27、ight vision. The human vision system processes the information detected by the eye in several perceptual channels: luminance, chrominance, and motion. Motion is only important for flicker threshold to the imaging system designer. The luminance channel takes the input from only the red and green rece
28、ptors. It is color blind. It processes the information in such a manner that the contrast of edges is enhanced. The chrominance channel does not have edge contrast enhancement. Since the luminance channel uses and enhances every red and green receptor, the resolution of the luminance channel is seve
29、ral times higher than the chrominance channel. The blue receptor contribution to luminance perception is negligible. Thus, the error introduced by lowering the blue resolution by one octave will be barely noticeable by the most perceptive viewer, if at all, as experiments at Xerox and NASA, AmesResearchCenter (R Martin, J. Gille, J. Larimer, Detectability of Reduced Blue Pixel Count in Projection Displays,SID Digest 1993)had demonstrated. Color perception is influenced by a process called assimilation or the Von
