Synaptics Incorporated
Transcapacitive and absolute capacitive sensing profiles

Abstract:

A processing system includes a sensor module configured to receive first and second signals from first and second sensor electrodes, respectively, and generate a combination signal. The processing system further includes a determination module configured to determine, using the first sensor electrode, an absolute capacitive coupling to an input object; determine, using the first and second sensor electrodes, a transcapacitive coupling; determine a ratio of the absolute to transcapacitive coupling; determine, using the combination signal, in absence of a predetermined low ground mass state, and when the ratio fails to exceed a predetermined threshold, first positional information regarding a location of the input object; and determine, when the ratio fails to exceed the predetermined threshold and in presence of the predetermined low ground mass state, second positional information regarding the location of the input object in the sensing region using an absolute capacitive scan.