A hybrid control scheme for driving current sources of pm-oled panel

This paper proposes a new amplitude width modulation (AWM) scheme for PM-OLED (passive matrix organic light emission device) data driver IC. The data driver controls brightness of OLED by adjusting the amplitude and width of the current through OLED. There are two conventional modulation schemes; pulse amplitude modulation (PAM) and pulse width modulation (PWM). The PWM suffers from lower light emitting efficiency at lower luminance levels. The PAM gives us large chip area, due to DACs for each column. The proposed AWM accurately controls the current level using MSB data and increases luminance using LSB data that improves inefficiencies of the PAM and PWM. We fabricated a one channel data driver chip with AWM using a 0.18 um standard CMOS process. The proposed scheme reduces power consumption 50% compared with PWM.