D/A converter for current-driven type source driver circuit in AM-OLED

摘要

A D/A converter applied in current-driven type source driver circuits for producing the data current with different gray levels is disclosed. The D/A converter comprise the following components. A column decoder is applied to transform input digital control signals (Dx) to column selecting signals (Cj). A row decoder is applied to transform the digital control signals (Dx) to row selecting signals (Ri). A unit cell array has current cells arranged in array form. Each current cell has a local current source and a local decoder, the local current source is chosen from at least three ones of different current intensity, and the local decoder can decode the column selecting signals and the row selecting signals for deciding to switch on or off the local current source thereof. The output currents of all the current cells switched on are summed up to produce the data current with a selected gray level.