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:
Jul. 17, 1984
Filed:
Nov. 19, 1982
Richard E Hester, Eden Prairie, MN (US);
Control Data Corporation, Minneapolis, MN (US);
Abstract
The voltage output of a differential amplifier is adjusted using an active feedback loop so that there is no direct current potential difference between the differential outputs of the differential amplifier. A potential difference at the differential output of a differential amplifier due to inherent bias or operating characteristics of the system is referred to as direct current offset voltage and the need to correct this condition may be referred to as differential output direct current offset voltage compensation. The feedback loop to accomplish this compensation consists of one or more stages of isolation and amplification driven by the output voltages of the differential amplifier and having a high input impedance to diminish loading of the amplifier outputs. A voltage peak detection system is used in order to isolate direct current voltage values from alternating current voltage values appearing at the differential amplifier output. This direct current peak detected value controls a current source which sums its output current to the current output of the differential amplifier to drive any direct current differential output to a minimum or zero value.