Advanced receive channel architecture

摘要

This relates to an architecture of a receive channel circuit used during both a spectrum analysis phase and a touch panel detection phase. Various components of the receive channel can be used during both the spectrum analysis phase and the touch panel detection phase. For example, a plurality of digital signal mixers used in the receive channel circuit can be used to demodulate signals during both a spectrum analysis phase and a touch sensor panel detection phase. In addition, the number of digital mixers needed in the receive channel can be reduced by dividing groups of signals to be demodulated into multiple sets of signals and demodulating each set at different times.

主权项

1. A method of scanning a touch sensor panel, the touch sensor panel comprising a plurality of drive lines and a plurality of sense lines, the method comprising:
a first mode for identifying one or more scanning frequencies corresponding to low noise, the first mode comprising:
deactivating one or more of the plurality of drive lines;sensing a first plurality of outputs from the plurality of sense lines;demodulating the sensed first plurality of outputs using a first plurality of mixers with a demodulation frequency;summing the first plurality of outputs;comparing the summation at the demodulation frequency to one or more other summation values at other frequencies; anddetermining the one or more scanning frequencies of the touch sensor panel based on the comparison.