A Touch Sensor Controller IC Adopting Differential Measurement for Projected Capacitive Touch Panel Systems

Abstract

A touch sensor controller IC with a novel touch sensing scheme is proposed for projected capacitive touch panel. The proposed IC adopts the differential measurements to amplify the capacitance variation. By using the proposed scheme, the sensitivity to a touch object is increased and the immunities to power noise and display noise are improved. The signal-to-noise ratio (SNR) of the touch sensor controller IC is 20.1 dB. The proposed IC fabricated via 0.13 μm CMOS process occupies a silicon area of 1.9 mm × 2.2 mm and consumes a dynamic current of 470 uA when the analog and digital supply voltages are 3.3 V and 1.8 V, respectively.