A PDM-Based Digital Driving Technique Using Delta-Sigma (Delta Sigma) Modulation for QVGA Full-Color AMOLED Display Applications

Abstract

We propose a digital driving technique using pulse-density modulation (PDM) for an active-matrix organic light-emitting diode (AMOLED) to effectively suppress the false image contour in conventional pulsewidth modulation (PWM) while achieving considerably low operating frequency. A compact first-order digital Delta Sigma modulator provides the PDM signal to the panel. A 2.2-inch QVGA AMOLED system using the proposed technique shows no false image contour problem while allowing relaxed minimum gate scan time.