RATIOMETRIC CIRCUIT

摘要

A ratiometric circuit (40) includes a differential capacitive sensor (42) for sensing a change in capacitance, a differential capacitive detector (46) operatively connected to the differential capacitive sensor for detecting a change in the capacitance of the differential capacitive sensor, an error voltage generator (48) operatively connected to the differential capacitive detector for generating a corrective voltage in response to the detected change in capacitance, and a bias circuit (50) operatively connected to the differential capacitive sensor for generating a bias voltage inversely proportional to and independent of a supply voltage for maintaining the ratiometricity between an output voltage of the differential capacitive sensor and the supply voltage.