A 620-pF-Compensated Dual-Mode Capacitance Readout IC for Subdisplay Panel Applications

Abstract

This letter presents a touch readout integrated circuit (IC) integrating both mutual- and self-capacitance sensing capabilities. The proposed IC aims to compensate for self-capacitance up to 620 pF by employing a combination of current-mode and capacitive-mode compensation techniques. A noise-monitoring scheme, based on the orthogonality of multicapacitance driving sequences, enhances readout performance by selectively detecting external noises during mutual-capacitance sensing operation. The IC achieved the measured signal-to-noise ratio (SNR) of 47.3, 30.6, and 36.1 dB in mutual-capacitance sensing and self-capacitance sensing of T/RX electrodes, respectively. By applying the noise-monitoring scheme, a 7-times higher noise power compared to the absence of external noise were successfully detected.