A Fully Differential Direct Sampling Touch Screen Readout With a Touch Vector Calibration for Ultrathin Organic Light-Emitting Diode Display

Abstract

This article presents a touch screen panel (TSP) readout IC (ROIC) for an ultrathin organic light-emitting diode (OLED) display, where display noise injection is severely increased. We adopted a fully differential (FD) and direct sampling receiver (RX) structure that supports digital in-phase and quadrature (IQ) demodulation to improve tolerance over display noise harmonics intermodulation. Furthermore, we present a touch vector calibration technique that reduces the digital processing burden originating from processing FD touch signals. The proposed IC consists of two chips fabricated in 55 and 130 nm CMOS processes and then packaged into a single package. The signal-to-noise ratio (SNR) is 54.03 dB with a 240 Hz frame rate for the 6.1-inch 16 × 34 ultrathin OLED TSP, while consuming 65.65 mW. IEEE