CALIBRATING CHARGE MISMATCH IN A BASELINE CORRECTION CIRCUIT

Various embodiments provide a processing module that calibrates a current-mode baseline correction system to account for features in an input device that lead to "offset" in output of a charge integrator used for sensing presence of an input object. The offset is a difference between a com...

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Bibliographic Details
Main Authors CHUNG Tae-Song, LIU Chunbo, LO Steve Chikin, BETANCOURT Rafael
Format Patent
LanguageEnglish
Published 08.12.2016
Subjects
CALCULATING
COMPUTING
COUNTING
ELECTRIC DIGITAL DATA PROCESSING
PHYSICS
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Summary:Various embodiments provide a processing module that calibrates a current-mode baseline correction system to account for features in an input device that lead to "offset" in output of a charge integrator used for sensing presence of an input object. The offset is a difference between a common mode voltage, which is the average voltage output of the charge integrator over a sensing cycle and a mid-rail voltage midway between high and low power supply voltages. Calibration is performed by adjusting an N-side and/or P-side current flow duration parameter until common mode voltage falls within a low offset window in which the offset is deemed to be sufficiently close to the mid-rail voltage. The resulting duration parameters are stored and used for current-mode baseline corrections when operating an associated sensor electrode for capacitive sensing.
Bibliography:Application Number: US201514731385