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Authors Tai-Ji An; Moon-Sang Hwang; Won-Jun Choe; Jun-Sang Park; Gil-Cho Ahn; Seung-Hoon Lee
Page pp.347-356
ISSN 1598-1657
Keywords Active-matrix organic light emitting diodes (AMOLED) ; column driver integrated circuit (IC) ; digital-to-analog converter (DAC) ; ramp signal ; two-step interpolation. ;
Abstract This work proposes a ramp signal-based column driving technique to maximize the area efficiency of the column driver integrated circuit (IC) for high-resolution active-matrix organic light emitting diodes (AMOLED) panels. The proposed column driving technique replaces the 2n reference voltages coming from the conventional n-bit resistor digital-to-analog converters (RDAC) with a single ramp signal, thereby reducing the area of the column driver IC by 44.3%. A weighted two-step interpolation structure, composed of the first-stage 6-bit ramp signal and the second-stage 2-bit amplifier DAC, reduces the required operation speed of the ramp signal under a limited 1-horizontal (1-H) time, while processing 8-bit image signals. The performance of the proposed column driving technique is verified with a 96-channel prototype IC fabricated in a 0.18 μm CMOS process. The deviation of voltage output (DVO) of the prototype IC are within ±6 mV, and the unit channel area is 4200 μm2.