Kevin W. Warren

Low-power circuits and technology for wireless digital systems

As CMOS technology scales to deep-submicron dimensions, designers face new challenges in determining the proper balance between aggressive high-performance transistors and lower-performance transistors to optimize system power and performance for a given application. Determining this balance is crucial for battery-powered handheld devices in which transistor leakage and active power limit the available system performance. This paper explores these questions and describes circuit techniques for low-power communication systems which exploit the capabilities of advanced CMOS technology.

A 10.5-in.-diagonal SXGA active-matrix display

A 157-dot-per-inch, 262K-color, 10.5-in.- diagonal, 1280 × 1024 (SXGA) display has been fabricated using a six-mask process with Cu or Al-alloy thin-film gates. The combination of high resolution and gray-scale accuracy has been shown to render color images and text with paperlike legibility. The low-resistivity gate metallization and trilayer-type TFTs with a channel length of 6-8 µm were fabricated with a six-mask process which is extendible to larger, higher-resolution displays. A combination of double-sided driving and active line repair was used so that open gate lines or data lines did not result in visible line defects. A flexible drive-electronics system was developed to address the display and characterize its performance under different drive conditions.

Active line repair for thin-film-transistor liquid crystal displays

A new method for repairing line defects during panel fabrication is described for high-resolution thin-film-transistor liquid crystal displays (TFT/LCDs). This approach uses electronic means in conjunction with physical rewiring to supply the appropriate data signal to the undriven segment of an open data line. Active line repair is simple and inexpensive, with the capacity for repairing numerous line defects. We have successfully implemented this repair approach on 10.4-in.-diagonal, 157-dpi prototype TFT/LCDs. This method is particularly suited for lower-volume, large-area, high-resolution TFT/LCDs, which are difficult to produce with high yield.