Patent ID: 11867584
Assignee: PSEMI CORPORATION
Field: Basic communication processes (Electrical engineering)
Classification: CPC G  B  H | IPC B  G  H

Claim 16:
17. A method of measuring pressure in presence of a variable parasitic capacitor, the method comprising:
providing a sense capacitor with a variable sense capacitance;
providing an offset capacitor;
providing a readout circuit having an integrating capacitor;
in an initial state
configuring the offset capacitor to sample, based on an auto-zeroing techniques, an output of the readout circuit to compensate for the parasitic capacitance;

in a charging phase following the initial state,
storing first charges across the sense capacitor; and
storing second charges across the offset capacitor;

in an integration phase, transferring the first and the second charges to the integrating capacitor, thereby generating a readout circuit output signal in correspondence of an input pressure, and
configuring the offset capacitor to center variations of the sense capacitor to a center of a full-scale of the readout circuit,
wherein the storing the first and the second charges and the transferring the first and the second charges are performed such that a charging and discharging of the offset capacitor is out of phase with respect to the sense capacitor.