Tunable baseline compensation scheme for touchscreen controllers

摘要

A method for compensating for panel capacitance the associated current is proposed, wherein the mutual capacitances of a capacitance sensing array are selectively coupled to drive voltages and to a self capacitance under test.

主权项

1. A capacitance sensing circuit comprising:
a first plurality of electrodes disposed along a first axis; a second plurality of electrodes disposed along a second axis such that a plurality of mutual capacitances are formed between at least one of the first plurality of electrodes and at least one of the second plurality of electrodes, wherein each of the first and second pluralities have a panel capacitance; a conversion circuit selectively coupled to the first and second pluralities of electrodes and configured to convert a self capacitance of at least one of the first plurality of electrodes or at least one of the second plurality of electrodes to a digital value; and a compensation circuit configured to produce a compensation signal for the conversion circuit based, in part, on at least one of the plurality of mutual capacitances.