A Gray-Level Dependent Pre-Emphasis Column Driver With Fast Settling for Active-Matrix LCD Applications

In this brief, simple analytical solutions for pre-emphasis driving conditions in active-matrix liquid crystal display (AMLCD) applications are presented. According to the solutions presented, the column driver with a gray-level dependent pre-emphasis (GLDP) function is designed for fast settling. The GLDP column driver is implemented without using additional frame memory. Also, modifications to the display system and integrated circuit fabrication process changes are not required. The GLDP column driver provides output voltage signals with variable pre-emphasis durations according to the magnitude of the gray-level shift to be driven. By applying the GLDP column driver, 8-mus reduction of the required one row line time was achieved on average. This one row line time reduction makes it possible to realize high performance and low cost AMLCDs. The 640 channel, full function GLDP column driver is fabricated by a 13.5-V 0.35-mum CMOS process.