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. 18, 1996
Filed:
Jun. 06, 1995
Douglas R Frey, Bethlehem, PA (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
A current mode VCA includes a negative feedback architecture around a gain core stage. An input signal is injected as a differential current into the signal path and is converted to a differential voltage by a transresistance stage having a dynamic impedance. The differential voltage is applied to a transconductance stage which limits the VCA's high frequency gain and stabilizes the feedback loop. The transconductance stage supplies a differential drive current to the gain core stage, which produces two differential output currents that sum to the differential drive current. The fraction of the drive current provided to each output current is controlled by the application of a control signal to the gain core stage. A current-to-voltage converter produces an output voltage in response to the output current. A differential feedback current is returned to the transresistance stage to complete the negative feedback loop and control the dynamic impedance of the transresistance stage to compensate for the gain extracted from the VCA and maintain constant loop gain.