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:
Jan. 27, 1987
Filed:
Nov. 06, 1984
David P Laude, Colorado Springs, CO (US);
Harris Corporation, Melbourne, FL (US);
Abstract
A low noise, high precision differential amplifier has an input bias and noise current cancellation circuit which includes a sensing device connected between common terminals of the differential pair and a reference potential. The sensing device is connected to a feedback circuit for supplying a bias and noise cancellation current to the amplifier inputs. The sensing device is constructed from a pair of matched transistors, which are also matched to the input differential pair. The feedback circuit includes two current mirrors constructed from four identically matched devices. A Darlington pair is located in the collector leg of each input transistor to improve the common mode rejection ratio. Added noise reduction is achieved by implementing the circuit with low surface noise transistors. A preferred embodiment of the circuit includes a resistance network for adjusting the bias voltages on the gates of the low surface noise transistors.