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. 30, 2009
Filed:
Nov. 01, 2007
Thomas L. Botker, Andover, MA (US);
Thomas L. Botker, Andover, MA (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
An amplifier topology includes an input stage comprising a differential pair which conducts respective output currents in response to a differential input signal. Bias current sources provide the pair's tail current and respective bias currents for the input stage in response to a drive voltage. After flowing through the input stage, most or all of the input stage bias currents are summed at a summing node, the summed currents being a current I. The input stage also has a feedback loop which includes a bias generator circuit arranged to receive I, and to provide the drive voltage to the bias current sources such that Iis maintained approximately constant. By so doing, the output impedance of the bias current sources is effectively increased, which serves to improve the amplifier's CMR and PSR characteristics.