HYBRID LARGE DYNAMIC RANGE CAPACITANCE SENSING

摘要

A processing system that includes a charge integrator, a compensation unit, and a fine signal processing unit. The compensation unit detects when the output of the charge integrator is outside of a certain range related to the dynamic range of the charge integrator and adds or subtract charge from an input of the charge integrator in response. The compensation unit records a count of the number of times that charge is added or subtracted and produces a coarse sensing result from this count. The fine signal processing unit processes the output of the charge integrator after charge is added or removed. The compensation unit processes the coarse sensing result and adds the processed value to fine sensing result from the fine signal processing unit to obtain a final output value. This final output value is the same value as if a charge integrator with a larger dynamic range were used.

主权项

1. A processing system for processing a signal received from a capacitive touch sensor driven with a sensing signal, the processing unit comprising:
a charge integrator coupled to the capacitive touch sensor at a first node; a fine signal processing unit configured to perform signal processing on an output of the charge integrator to generate a fine logic output; and a compensation unit configured to:
subtract charge from or add charge to the first node in discrete amounts of large during a sensing half period of the sensing signal,perform signal processing on a coarse sensing result that is based on the charge that is added to or subtracted from the first node during the sensing half period to generate a coarse logic output, andadd the coarse logic output to the fine logic output to generate a processed signal output.