Touch sense interface circuit

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 (Vp1) and a negative threshold (Vm1) of the first comparator in response to a count outputted by the first counter,
• sets a positive threshold (Vp2) and a negative threshold (Vm2) 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.

A method with a touch panel, the touch panel including a plurality of pads, comprising:

• measuring power of electromagnetic (EM) noise in a first pad and measuring power of EM noise in a second pad;
• comparing the power of EM noise measured in the first pad to the power of EM noise measured in the second pad;
• and
• providing an indication of a touch occurring at the first pad when the power of the EM noise measured in the first pad is a pre-selected amount greater than the power of the EM noise measured in the second pad.