Patent ID: 8599169

Claim:
A noise touch sensing circuit for detecting electromagnetic (EM) noise at pads of a touch panel, the noise touch sensing circuit comprising: a first comparator with hysteresis having an input node coupled to a first pad of a touch panel, the first comparator with hysteresis outputting a first signal responsive to magnitude of EM noise at the first pad; a second comparator with hysteresis having an input node coupled to a second pad of the touch panel, the second comparator with hysteresis outputting a second signal responsive to magnitude of EM noise at the second pad; a first counter for counting toggling of the first signal; a second counter for counting toggling of the second signal; and a threshold controller, coupled to the first comparator with hysteresis and to the second comparator with hysteresis, wherein the threshold controller: sets a positive threshold (V p1 ) and a negative threshold (V m1 ) of the first comparator in response to a count outputted by the first counter, sets a positive threshold (V p2 ) and a negative threshold (V m2 ) of the second comparator in response to a count outputted by the second counter, and outputs a noise touch sensing signal in response to a difference between the count of the first counter and the count of the second counter.