AC amplifiers with ultra‐low corner frequency by using bootstrapping

Authors :: Carlos A. De La Cruz-Blas
Alfonso Carlosena
Maite Martincorena-Arraiza
Antonio J. Lopez-Martin
Universidad Pública de Navarra. Departamento de Ingeniería Eléctrica y Electrónica
Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa. ISC - Institute of Smart Cities
Nafarroako Unibertsitate Publikoa. Ingeniaritza Elektriko, Elektroniko eta Telekomunikazio Saila
Source :: Electronics Letters, Vol 57, Iss 5, Pp 203-205 (2021), Academica-e. Repositorio Institucional de la Universidad Pública de Navarra, instname
Publication Year :: 2021
Publisher :: Wiley, 2021.
Abstract: A novel architecture for an AC (i.e. high-pass) amplifier is proposed allowing a drastic reduction of the cutoff frequency to the sub-Hertz range. It builds upon the classic AC configuration with a high gain amplifier and a parallel RC circuit in the feedback loop, by increasing the feedback resistance through bootstrapping. Resistance multiplying factors higher than four orders of magnitude are easily achievable. The basic principle can be applied to several practical implementations, though in this letter it is demonstrate with measurement results of an op-amp based discrete implementation. This work was financially supported by the following grants from the Spanish Research Agency: TEC2016-80396-C2-1-R and PID2019-107258RB-C32 (AEI/FEDER). M.Martincorena Arraiza was funded by the Ministry of Universities under grant BES-2017-080418.