Capacitive touchscreen system with touch position encoding during analog-to-digital conversion

Abstract

Disclosed herein are various embodiments of circuits and methods in a capacitive touchscreen system that eliminate the need to digitize an entire array of pixel signals obtained from a touchscreen. Instead, regions of interest, or projections of object or touch signal clusters, from touchscreenare employed to encode the coordinates or positions of objects or touches in an analog-to-digital converter (ADC). Encoding of object positions occurs during digitization of the analog signal clusters, which eliminates the need to separately digitize individual touchscreen signals. The disclosed circuits and methods reduce the number of signal processor channels that might otherwise be required, and lead to power consumption reduction in the capacitive touchscreen system, as well as in reducing the area required to implement the circuit architecture in an integrated circuit.