Title :
New fully differential variable gain instrumentation amplifier based on a DDA topology
Author :
Gano, António J. ; Franca, José E.
Author_Institution :
Dept. of Electron., INETI, Lisbon, Portugal
Abstract :
A two-stage Fully differential Differential Difference Amplifier (FDDA) cell is presented. The input linear transconductance ports and the two stage topology are referred and the open-loop characteristics discussed. Based on this fully differential analogue cell, a new fully differential variable gain instrumentation amplifier is proposed. This new topology is based on the previous described FDDA cell, with a voltage-controlled differential transconductance cell used on the feedback loop of the amplifier to control the amplifier´s gain. The gains can be continuously tuned within one decade variation range by a controlling voltage Vg. This decade range is set by two equal feedback resistors Rg. Simulation results are discussed and applications of these analogue building blocks in a modular architecture for smart sensor development are referred to
Keywords :
analogue processing circuits; feedback amplifiers; gain control; instrumentation amplifiers; transfer functions; analogue cell; analogue processing chains; class AB buffer; continuously tuned gain; differential difference amplifier topology; equal feedback resistors; feedback loop; folded cascode topology; fully differential; gain control; input linear transconductance ports; modular architecture; open-loop characteristics; smart sensor development; transfer function; two stage topology; variable gain instrumentation amplifier; voltage-controlled differential transconductance cell; Differential amplifiers; Feedback loop; Gain; Instruments; Intelligent sensors; Open loop systems; Resistors; Topology; Transconductance; Voltage control;
Conference_Titel :
Instrumentation and Measurement Technology Conference, 1999. IMTC/99. Proceedings of the 16th IEEE
Conference_Location :
Venice
Print_ISBN :
0-7803-5276-9
DOI :
10.1109/IMTC.1999.776720
