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:
Aug. 10, 1999
Filed:
Aug. 04, 1997
Daniel D Alexander, Gilbert, AZ (US);
David J Anderson, Scottsdale, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A circuit and method control the common-mode potential at an output (17, 18) of a fully differential amplifier (32) by feeding forward a common-mode correction signal through the amplifier. An input signal (V.sub.IN+ -V.sub.IN-) is amplified in the amplifier to produce a differential output signal (V.sub.O- -V.sub.O+) at the output. A common potential of the differential inputs (37, 38) of the amplifier is sensed with a transistor (54, 56) biased to a reference voltage (V.sub.CM) and amplified through the amplifier to produce a common-mode correction signal to offset a common-mode component of the differential output signal. A feedback circuit (33-36) is used to develop the common potential from the common-mode component.