(Wiley, 2021) Martincorena Arraiza, Maite; Carlosena García, Alfonso; Cruz Blas, Carlos Aristóteles de la; Beloso Legarra, Javier; López Martín, Antonio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
A family of capacitively coupled alternating current (AC) amplifiers featuring ultra-low (below 1 Hz) corner frequency is presented. This is achieved by using high-gain devices which actively boost feedback resistance and thus reduce corner frequency. This procedure is often termed, though with a different purpose, as 'bootstrapping'. The proposed architectures are very general and admit several possible practical implementations. To demonstrate their usefulness, the circuits are implemented with two operational amplifiers (OA), but other active devices such as operational transconductance amplifiers (OTAs) can be alternatively used. All circuits have been theoretically analyzed, extensively simulated and measured, exhibiting high-pass cutoff frequencies as low as 30 mHz.
