A Readout IC for Capacitive Touch Screen Panels With 33.9 dB Charge-Overflow Reduction Using Amplitude-Modulated Multi-Frequency Excitation

This article presents a readout integrated circuit (ROIC) for capacitive touch-screen panels (TSPs) employing an amplitude-modulated multiple-frequency excitation (AM-MFE) technique. To prevent charge overflow, which occurs periodically at the beat frequency of frequencies, ROIC modulates amplitude voltages mixing derived from frequencies. Thus, can sense signal without overflow and maximize signal-to-noise ratio (SNR) by increasing up to sensing range circuit. The proposed was fabricated in 0.13- $\mu \text{m}$ standard CMOS process measured with 32-in 104 notation="LaTeX">$\times $ 64 panel using 1 10 mm metal pillars. It reduces 33.9 dB compared operation AM-MFE. In addition, achieves frame rate 2.93 kHz, SNRs 41.7 61.6 pillars, respectively.