INPUT COMMON MODE CONTROL USING A DEDICATED COMPARATOR FOR SENSOR INTERFACES

摘要

Various embodiments of the invention allow for low-noise, high performance input common mode voltage control in capacitive sensor front end amplifiers. In certain embodiments overcome the shortcomings of the prior art by implementing a full voltage swing common mode voltage comparator in a parallel feed-forward path to compensate large common mode input signal variations.

主权项

1. A comparator-based common mode voltage control circuit comprising:
a differential amplifier comprising a differential amplifier input to receive a differential input signal that carries an input common mode voltage; and an input common mode feedback comparator comprising a first reference signal input to receive a first reference signal, the feedback comparator compares the differential input signal to the first reference signal to generate a comparison result that indicates when the input common mode voltage exceeds a predetermined threshold value with respect to the first reference signal; and a correction signal that is applied to the differential amplifier input to control the input common mode voltage based on the comparison result.