Deconvolution-based capacitive touch detection circuit and method

A method for measuring a capacitance, comprising:

• (a) operating row drive circuitry of analog-digital circuitry coupled to row conductors and column conductors of a touch screen panel for producing a first digital signal representative of cross-coupling capacitances of the touch screen panel so as to superimpose charge transfers from cross-coupling capacitances of at least a plurality of the row conductors to a first column conductor thereby causing the first digital signal to be a convoluted signal which is a function of the cross-coupling capacitances of at least the plurality of row conductors;
• (b) producing a second digital signal which represents digital touch-induced capacitance change values caused by the presence of a touch near a cross-coupling capacitance of the touch screen panel by subtracting base line data representing the cross-coupling capacitances from the first digital signal;
• and
• (c) deconvoluting the second digital signal to produce a third digital signal which represents a magnitude map of the touch-induced capacitance change values.

A system for measuring a capacitance, comprising:

• (a) means coupled to row conductors and column conductors of a touch screen panel for producing a first digital signal representative of cross-coupling capacitances of the touch screen panel so as to superimpose charge transfers from cross-coupling capacitances of at least a plurality of the row conductors to a first column conductor thereby causing the first digital signal to be a convoluted signal which is a function of the cross-coupling capacitances of at least the plurality of row conductors;
• (b) means for producing a second digital signal which represents digital touch-induced capacitance change values caused by the presence of a touch near a cross-coupling capacitance of the touch screen panel by subtracting base line data representing the cross-coupling capacitance changes from the first digital signal;
• and
• (c) means for deconvoluting the second digital signal to produce a third digital signal which represents a magnitude map of the touch-induced capacitance change values.