Patent ID: 6731121
Filing Date: 2004-05-04
Classification: G01D

Abstract:
A capacitive transducer interface circuit that produces an output value that is proportional to a change in capacitance of a sense capacitor in a capacitive transducer comprising:an integrated circuit having: (1) a capacitive adjustment section that is electrically connected to the sense capacitor, including: (a) a capacitor array circuit; (b) means for configuring the capacitance of the capacitor array circuit and for combining the capacitance of the capacitor array circuit with the capacitance of the sense capacitor to provide a substantially null value when the capacitive transducer is in a null position; and (2) a capacitive trans-impedance amplifier section that is electrically connected to the sense capacitor and the capacitive adjustment section, including: (a) a trans-impedance amplifier means for producing an output signal that is proportional to the change in capacitance of the sense capacitor; and (b) means for configuring the gain of the capacitive trans-impedance amplifier to provide a desired dynamic range.