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:
Jun. 10, 2003
Filed:
Nov. 06, 2001
Frank G. Cooper, Dix Hills, NY (US);
Keystone Thermometrics, St. Marys, PA (US);
Abstract
An impedance converter module has a phase reversal circuit to receive a 2-wire excitation signal at first and second terminals, and to provide a polarized excitation signal with a predetermined polarity based on the 2-wire excitation signal. A series current path has a sense resistor connected in series with a variable impedance source. The polarized excitation signal is applied across the series current path. An output-voltage-sense circuit provides an output-voltage-sense signal based on a voltage across the series current path. A current mirror provides a drive signal to a ratiometric device based on current flowing through the series current path. Differential amplifiers receive a ratiometric response signal from the ratiometric device, and output measurement signals based on the ratiometric signal. A summing node combines the measurement signals to provide a single-ended ratiometric signal. The variable impedance source is controlled to provide a two-wire response signal at the 2-wire terminals based on the single-ended ratiometric signal and the output-voltage-sense signal.