A current-mode display driver IC using sample-and-hold scheme for QVGA full-color a MOLED displays

Abstract

A display driver IC based on a current-sink driving scheme has been developed for QVGA (240 x 320), 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 mu m. The controller block generates control signals for the source driver and UPS drivers (emission and scan driver), which are integrated on the panel glass. The current-mode driver IC was fabricated in a 0.18-mu m CMOS technology (two poly and four metals) with 5.3-V high-voltage transistor devices