Patent ID: 6516672
Filing Date: 2003-02-11
Classification: G01L,H03M

Abstract:
A process pressure transmitter having hysteresis compensation, comprising:an output circuit configured to provide an output related to a sensed pressure; a pressure sensor comprising: a pressure cell having an interior to form a main cell cavity; a deflectable diaphragm which deflects in response to an applied pressure having a first side and a second side configured to divide the main cell cavity into first and second cavities; first and second electrodes in the first cell cavity proximate the diaphragm configured to form respective first and second capacitors therewith; third and fourth electrodes in the second cell cavity proximate the diaphragm configured to form respective third and fourth capacitors therewith; an analog to digital converter coupled to the first, second, third and fourth electrodes, comprising: a sigma delta converter having a first input coupled to the first electrode and a second input coupled to the third electrode and having an output related to the applied pressure; and at least one charge inverter amplifier including a switch capacitor to couple the second electrode to the first input of the sigma delta converter.