A touch controller using differential sensing method for on-cell capacitive touch screen panel systems

Abstract

A touch controller is proposed for on-cell capacitive touch screen panel systems. The proposed IC adopts the differential sensing method to enhance the dynamic range of sensing voltage and to be robust to display noise. The measurement results show that the maximum reporting rate, jitter tolerance, and signal-to-noise ratio (SNR) are 140 Hz, ±0.3 mm, and 12 dB, respectively, when evaluated with a 13.3-inch wide extended graphics array (WXGA) liquid crystal display (LCD) panel with the on-cell touch screen. The proposed IC fabricated via 0.35 μm CMOS process technology occupies a silicon area of 4 mm x 5 mm and consumes a power of 19 mW when the supply voltage is 3.3 V.