|Keywords:||Electrical engineering; 3D; Active resonator; Bootstrap; Capacitive sensing; Oscillator; Touch screen control|
|Full text PDF:||http://www.escholarship.org/uc/item/363614nd|
An oscillator-based self-capacitance sensing front end system is designed for the commercial grade projected capacitive touch panel. The self-capacitance architecture has potential in terms of 3D extended-range sensing in the vertical (Z) direction however planar resolution (X and Y directions) resolution had to be compromised if it were directly applied to the panel, which is designed for change-transfer based sensors. Incorporating the technique of bootstrapping to null the coupling capacitance between sensing channels, planar resolution can be restored and better Z direction range can be achieved. The design is realized in 65nm and has submitted to TSMC for fabrication.