A New Realization of Electronically Tunable Multiple-Input Single-Voltage Output Second-Order LP/BP Filter Using VCII

Leila Safari,Gianluca Barile,Vincenzo Stornelli,Giuseppe Ferri,Mattia Ragnoli

doi:10.3390/electronics11040646

Abstract

In this paper, a new realization of electronically tunable voltage output second-order low-pass (LP) and band-pass (BP) filter is presented. The circuit has a multiple-input single-output structure, and LP and BP outputs are provided using the same structure. One electronically variable second-generation voltage conveyor (VCII), whose impedance at the Y port can be electronically varied using a control current (Icon), two capacitors, and one resistor are used. By changing the value of Icon, the impedance value at the Y port can be electronically varied; therefore, the value of ω0 can be tuned. This feature helps to reduce the number of passive components used. Interestingly, the LP and BP outputs are provided at the low-impedance Z port of the VCII, and there is no need for an extra voltage buffer for practical use. The circuit enjoys a simple realization consisting of only 24 MOS transistors. Simulation results using PSpice and 0.18 μm CMOS parameters are provided. The value of ω0 can be varied from 1.2 MHz to 1.7 MHz, while Icon varies from 0 to 50 µA, with a power consumption variation from 244 µW to 515 µW.

Highlights

Filter design represents a widespread and important topic, due to the interesting application in communication, measurement, instrumentation, control, and signal processing [1,2,3]
Current mode signal processing has been the focus of researchers in the design of various types of active filters
Current mode signal processing provides the opportunity of realizing electronically tunable filters, which are highly suitable for the requirements of full integration

Summary

Introduction

Filter design represents a widespread and important topic, due to the interesting application in communication, measurement, instrumentation, control, and signal processing [1,2,3]. Current mode signal processing provides the opportunity of realizing electronically tunable filters, which are highly suitable for the requirements of full integration. The current mode active filters reported in [1,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,22] suffered from a common weakness of applications requiring voltage signals In these circuits, the output signal was either in current form, making them unsuitable for applications requiring voltage signals, or in voltage form provided on a high impedance port, necessitating additional voltage buffers for practical use. SRI (poSRsiIt(ivpoes, intievgea, ntievgea)tive) SRV (pSoRsViti(vpoe,sintievgea, ntievgea)tive)

48 Ω244 kΩ

Conclusions