A Current-Mode Display Driver IC Using Sample-and-Hold Scheme for QVGA Full-Color AMOLED Displays

A display driver IC based on a current-sink driving scheme has been developed for QVGA (240times320), low-temperature poly-silicon (LTPS) active matrix organic light-emitting diodes (AMOLEDs) displays. The current-mode driver IC consists of a source driver block and a controller block. It uses a sample-and-hold scheme in the source driver block. The source driver block has 720 channel outputs, an 8-bit segmented DAC, a pre-charge generation block, and a 64-level gray scale (64 selections out of 256 gray levels for Gamma correction) per channel. The source driver output current ranges from 10 nA to 10 mum. The controller block generates control signals for the source driver and LTPS drivers (emission and scan driver), which are integrated on the panel glass. The current-mode driver IC was fabricated in a 0.18-mum CMOS technology (two poly and four metals) with 5.3-V high-voltage transistor devices