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:
Feb. 15, 1994
Filed:
Nov. 20, 1992
John A Olmstead, Cape May Court House, NJ (US);
Salomon Vulih, Neshanic, NJ (US);
Harris Corporation, Melbourne, FL (US);
Abstract
A differential amplifier embodying the invention includes a differential stage whose total output current is sensed and whose 'tail' and output current is maintained relatively constant over a large common mode voltage range by means of a current feedback loop. This feature eenables the differential amplifier to accurately amplify low amplitude signals riding on a very large common mode signal. The tail current to the differential amplifier is supplied by a controllable current source. The tail current flows via two differentially connected transistors in two differential output terminals and is divided between them as a function of the voltage applied to two differential signal input terminals. The amplitude of the tail current is set by a current level setting current source connected to a summing node. An amplifier and current mirroring network is connected between the summing node and the controllable current source. A current sensing and mirroring network is connected to the two differential outputs for sensing the total current flowing and feeding back a current proportional thereto to the summing node for maintaining the tail current relatively constant over wide variations in the voltage applied to the signal input terminals.