A digitally driven pixel circuit with current compensation for AMOLED microdisplays

Yuan Ji, Feng Ran, Hongguang Xu, Weixin Shen, David J Lilja

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

A novel digitally driven pixel circuit for active-matrix organic light-emitting diode (OLED) microdisplays is proposed and evaluated. This circuit supports both pulse width modulation and pulse density modulation digital drive approaches. Only three transistors and one capacitor are required per pixel for the proposed circuit. A current mirror is used to compensate for the pixel current changes that occur because of the degradation of the OLEDs over time. The compensation current depends on the potential of the common cathode, the properties of the current mirror, and the Width/Length (W/L) ratio of the drive transistor. The proposed digital pixel circuit also has advantages in circuit layout compared with analog pixel circuits.

Original languageEnglish (US)
Pages (from-to)465-472
Number of pages8
JournalJournal of the Society for Information Display
Volume22
Issue number9
DOIs
StatePublished - Sep 1 2014

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Keywords

  • AMOLED (active-matrix organic light-emitting diode)
  • CMOS
  • OLED degradation compensation
  • digital drive
  • microdisplay
  • pixel circuit

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