Deconvolution-based capacitive touch detection circuit and method

摘要

A capacitance measuring system includes analog-digital circuitry (15) coupled to row conductors (2i) and column conductors (3i) of a touch screen panel (13A) for producing a first digital signal (DATA) representative of cross-coupling capacitances (CSENij). Row drive circuitry (45) superimposes charge transfers from cross-coupling capacitances of the row conductors to a first column conductor to cause the first digital signal to be a convoluted signal. Calibration circuitry (39,40) subtracts base line data from the first digital signal to produce a second digital signal (&Dgr;DATA) representing touch-induced capacitance change values (&Dgr;CSENIJ). A deconvolution circuit (44) deconvolutes the second digital signal to produce a digital output (58) representing a magnitude map of the touch-induced capacitance change values.