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A time‐delay technique to improve GBW on negative feedback amplifiers
Author(s) -
Alves Luis Nero,
Aguiar Rui L.
Publication year - 2008
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.441
Subject(s) - negative feedback amplifier , amplifier , bandwidth (computing) , gain–bandwidth product , computer science , feedback loop , operational amplifier , current feedback operational amplifier , negative feedback , electronic engineering , positive feedback , direct coupled amplifier , control theory (sociology) , open loop gain , fully differential amplifier , electrical engineering , engineering , telecommunications , voltage , computer security , control (management) , artificial intelligence
This paper presents a new method to improve the GBW (gain‐bandwidth product) on negative feedback amplifiers. The proposed method is based on the introduction of time‐delay elements in the feedback loop, which can be exploited to retrieve significant bandwidth enhancements. This delayed feedback concept is analyzed, and considerations are presented for first‐order amplifiers, based on theoretical analysis. The concept is simulated and further demonstrated in a practical example using a series‐shunt feedback amplifier with a TL081 operational amplifier (OA) and a 36‐m‐long coaxial cable as a delay element. Measured experimental results show a maximum bandwidth improvement of almost 90%, from a theoretical maximum of 141%. Copyright © 2007 John Wiley & Sons, Ltd.