A Column-Parallel On-Programming Pixel-Current Readout Embedded in an OLED Display Driver IC

Abstract

This article presents an organic light-emitting diode (OLED) driver IC that embeds a column-parallel real-time pixel-current readout circuit for sensing current during actual display operation. It features a folding integrator (FI) for high sensitivity and wide dynamic range (DR) in current sensing, along with a source-driven pixel and an AFE-combined voltage driver (ACD) to facilitate current sensing during display data programming. A channel-shared common-mode noise rejection filter (CMRF) is also presented to effectively suppress channel-common panel noise. The 16-channel prototype chip was fabricated using a 180-nm CMOS process. Measurement results show that the FI achieves 80-mV/nA sensitivity and a 16-fold DR extension, while the CMRF offers up to 63 dB of noise rejection. The 11-bit current readout exhibits a maximum differential nonlinearity (DNL) of 0.33 LSB, an integral nonlinearity (INL) of 1.7 LSB, an rms noise of 1.98 digital number (DN), and a signal-to-noise ratio (SNR) of 60.3 dB. Real demonstrations with LED also validate the pixel-current sensing functionality and performance of the proposed chip.