SERIES OFFSET CAPACITOR FOR INTERNAL REFERENCE BASED CAPACITIVE SAMPLING

摘要

A system and method for reducing the power required for a capacitive sensing measurement and for simplifying a sample capacitor signal offset while reducing charge injection during synchronous rectification by enabling the touch sensor to begin a measurement cycle at an arbitrary voltage rather than forcing the touch sensor to have a precise known voltage.

主权项

1. A method for reducing power consumption of a capacitive sensing touch sensor, said method comprising:
providing a plurality of electrodes disposed in an orthogonal and co-planar array of two sets of electrodes, wherein the two sets of electrodes always perform different functions from each other, switching between a drive function and a sense function; providing a touch controller that transmits drive signals to the plurality of electrodes and which receives sense signals from the plurality of electrodes, wherein the touch controller includes a signal sampling circuit for receiving the sense signals; initializing the signal sampling circuit by enabling the signal sampling circuit to use an arbitrary voltage that is present on the signal sampling circuit before receiving the sense signals; receiving the sense signals by the signal sampling circuit; and determining a position of at least one object in contact with the plurality of electrodes using the sense signals.