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US 2014/0176482 A1Published application
Capacitive touch sensing system with interference rejection
AssigneeBroadcom Corporation
InventorsGuo Wen Wei, Tom W. Kwan
Life of this patent
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AssigneeBroadcom Corporation
InventorsGuo Wen Wei, Tom W. Kwan
Estimating the term…
An interference tolerant capacitive touch sensor readout circuit having improved power and area efficiency is disclosed. Interference rejection for the capacitive touch sensing system is realized by transferring charge between a capacitive touch sensor and the readout circuit at frequencies outside bands where a level of interference is unacceptable. Improved power and area efficient come from the simplicity of the readout circuit which comprises a switched-capacitor integrator, a comparator, a digital accumulator and number of switches for driving a touch sensor and a capacitive feedback loop. The readout circuit is capable of interfacing with both self and mutual capacitance sensor to achieve compatibility with a larger collection of sensors and provides additional sensing and diagnostic functionalities.
A method of sensing capacitance of a capacitive touch sensor and rejecting interference coupled-in through the touch sensor during a conversion cycle, the method comprising:
A circuit for sensing capacitance of a capacitive touch sensor and rejecting interference coupled-in through the touch sensor during a conversion cycle, the circuit comprising:
A circuit for sensing capacitance of a capacitive touch sensor and rejecting interference coupled-in through the touch sensor during a conversion cycle, the circuit comprising:
Dependencies are inferred from the claim text.