The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 04, 2004
Filed:
Aug. 19, 2002
Ying Hsu, Huntington Beach, CA (US);
Christ Saunders, Laguna Niguel, CA (US);
Kirk Su, Irvine, CA (US);
Microsensors Corp., Costa Mesa, CA (US);
Abstract
A transducer interface circuit ( ) for use with a capacitive sensor ( ). The interface circuit ( ), provided on application specific IC, includes numerous trims and adjustments that permit it to operate with a differential, balanced-pair sensors ( A) or a singled-ended sensor ( ). In particular, the circuit ( ) provides a capacitive adjustment section ( ) and a capacitive trans-impedance amplifier section ( ) that are configured with capacitor adjustment controls ( ) and gain adjustment controls ( ) that, along with other controls, are provided as control registers. The capacitive trans-impedance amplifier section ( ) periodically reverses the voltages across the sensor ( ), and the capacitive adjustment section ( ), after blanking a feedback capacitance (CF) that is used to integrate excess charge caused by a difference in capacitance. A low pass filter section provides bandwidth adjustment without requiring any external components. An output buffer section ( ) includes further trim controls for gain and offset, is also governed by an offset selection bit SOFF that adjusts the output range to be optimally suited for the balanced-pair sensors ( A) or a singled-ended sensor ( B).