A low-voltage square-root domain n-th order multifunction FLF filter topology

Abstract

A novel n-th order Follow the Leader Feedback (FLF) multifunction low-voltage filter topology, realized by employing the concept of Square-Root Domain (SRD) filtering, is introduced in this manuscript. The realization of the SRD filter topology is achieved by utilizing the corresponding FLF conventional topology and performing a transposition into SRD, through an appropriate set of complementary operators. As a design example, a 5th-order SRD FLF filter has been designed and its performance has been evaluated through simulation results, where the most important performance factors have been considered.

Sinh-Domain linear transformation filters

“…The compression of the input current can be performed by the following ways: (a) through the logarithmic V-I relationship of bipolar transistor in active region or MOS transistor in weak inversion -the derived filters are known in the literature as log-domain filters Frey, 1993;Kontogiannopoulos & Psychalinos, 2005;Mahattanakul & Toumazou, 1999;Perry & Roberts, 1996;Psychalinos, 2006;Shah & Khanday, 2009a, 2009b;. (b) through the square-root V-I relationship of MOS transistor in strong inversion -the derived filters are known as square-root domain filters (Lopez-Martin & Carlosena, 2001;Psychalinos, 2007aPsychalinos, , 2007bPsychalinos, 2008a;Psychalinos & Vlassis, 2002a;Stoumpou, Khanday, Psychalinos, & Shah, 2009) and (c) through the inverse of the hyperbolic sine function realised by translinear loops formed by bipolar transistors in active region or MOS transistors in weak inversion -the derived filters are known as Sinh-Domain filters (Frey, 1999;Frey & Tola, 1999;Haddad & Serdijn, 2006;Kasimis & Psychalinos, 2012a, 2012bKatsiamis & Drakakis, 2005;Katsiamis, Glaros, & Drakakis, 2008;Lopez-Martin & Carlosena, 1999a, 1999bPoort, Serdijn, Mulder, & van der Woerd, 1999;Serdijn, Kouwenhoven, Mulder, & van Roermund, 1999). This type of companding filters offers an inherent class-AB operation, while in the cases of square-root domain and log-domain filters a class-AB pseudo-operation is achieved by utilising an input current splitter, two identical class-A signal paths and subtracting the intermediate output currents.…”

1.5 V square‐root domain universal biquad filters

“…A number of second‐order SRD filters have been already proposed in the literature . All of them are multifunction filters in the sense that they are not able to simultaneously realize all the aforementioned filter functions.…”