This book provides comprehensive coverage of the major gyrator circuits, simulated inductors and related synthetic impedances. It offers a thorough review of research in this field to date, and includes an exceptionally wide range and number of circuit examples, along with their relevant design equations, limitations, performance features, advantages and shortcomings. The book provides useful information for academics wishing to keep up-to-date with developments in the design of gyrators and other related synthetic impedances, and can also be used as a reference guide by electronics engineers looking to select appropriate circuits for specific applications. The book begins with an introduction to the key concepts of integrated and simulated inductors. Later chapters go on to cover the gyrators, simulated inductors and other related synthetic impedances realised with a wide variety of active devices ranging from bipolar and MOS transistors to the ubiquitous IC op-amps, operational transconductance amplifiers, current conveyors, current feedback op-amps and numerous other modern electronic circuit building blocks.
Inspec keywords: electric immittance; operational amplifiers; bipolar integrated circuits; feedback amplifiers; electric impedance; resistors; CMOS integrated circuits; current conveyors; gyrators; inductors; impedance convertors
Other keywords: op-amps; operational floating amplifiers; transistor-level realization; operational transconductance amplifier; modern active building blocks; floating resistors; four-terminal floating nullor; current feedback-op-amp; simulated inductors; impedance simulators; OMA; synthetic impedances; FTFN-OFA; operational mirrored amplifiers; bipolar active transformers; impedance synthesis; electronically controllable grounded resistors; CMOS active inductors; gyrators; related immittances; CMOS active transformers; current conveyors; integrated inductors; voltage-controlled impedances; bipolar active inductors
Subjects: Resistors; Bipolar integrated circuits; CMOS integrated circuits; Inductors and transformers; General electrical engineering topics; Amplifiers; Active filters and other active networks
This chapter first reviews the basic oneand two-port circuit elements and then highlights the basic characterization and impedance inverting property of the gyrator. To place the scope and the contents of this monograph in the right perspective, this chapter then discusses several other issues such as commercially available passive inductors and Coilcraft, difficulties in micro-miniaturization of inductors, integrated circuit spiral inductors on the chip and use of ANSYS and COMSOL software in the analysis and characterization of on-chip inductors. The chapter ends by highlighting the need for and the importance of the simulated inductors which constitute a dominating topic in this monograph.
This chapter deals with the realization of gyrators and other impedance simulation circuits using integrated circuit (IC) operational amplifiers (op-amps) as the main building blocks. The traditional voltage-mode op-amp is well recognized as the workhorse of analog circuit design, and therefore, it is no surprise that IC op-amps were considered to be the most appropriate building blocks for realizing gyrators and various other kinds of synthetic impedances. In this chapter, we present a wide variety of op-amp circuits for realizing grounded and floating synthetic impedances of various kinds. A number of general methods of synthesizing grounded and floating synthetic impedances have also been elaborated.
The operational transconductance amplifier-capacitor (OTA-C) circuits were evolved to provide analog signal processing/signal generation circuits which could be fully integrated in to bipolar or CMOS technology. Thus, apart from their applications in the realization of oscillators, multipliers, nonlinear waveform generators and analog continuous-time filtering, OTA-C circuits and sometimes a combination of OTAs and op-amps have been extensively employed in the realization of gyrators and synthetic impedances of various types. This chapter presents an account of the most prominent works done in this area and highlights certain common synthesis methodologies of deriving such circuits.
This chapter discusses prominent contributions made over the last five decades on the evolution of gyrators, synthetic inductances and other related immittances using current conveyors (CCs) and their numerous variants developed over the years. The various circuits using the most basic forms of CCs, namely the first-generation CCs (CCI) and the second-generation CCs (CCII) have been elaborated first. This is then followed by the circuits employing an electronically controllable version of CCII called controlled second-generation current conveyor. Finally, numerous recent circuits based on different variants of CCs such as dual-output CCIIs, differential voltage CCs, third-generation CCs, differential difference CCs, inverting CCII, dual-X CCII and fully differential CCII and numerous combinations thereof have been dealt with. A number of applications of the various synthetic impedances have been elaborated.
Besides the op-amp based and operational transconductance amplifier-based gyrators and impedance simulators, the current-feedback operational amplifier (CFOA)-based circuits of these elements are attractive because of the commercial availability of the CFOA AD844 as an off-the-shelf IC. In this chapter, we consider the prominent circuits for realizing gyrators, lossless grounded inductance (GI)/ lossless floating inductance (FI) circuits as well as the more generalized generalized positive impedance converter/inverter and generalized negative impedance converter/inverter elements using CFOAs. It is found that a class of economic impedance simulation circuits based on the use of single CFOA offer the attractive features of single resistance tunability which is not available in the well-known single op-amp-based simulators of the same kind of impedances. A number of inductors and resonators using CFOA poles and a class of GI/FI simulators using a modified CFOA have also been included.
This chapter presents an overview of the significant contributions made on the realization of gyrators and various other kinds of impedances with particular emphasis on floating inductance simulation for which a specific form of nullor namely the so-called four-terminal-floating-nullor (FTFN) and the operational floating amplifier and somewhat similar appearing element, namely the operational mirrored amplifiers (OMAs) have been found to be particularly versatile. Most of the FTFN-based circuits described in this chapter can be practically implemented using commercially available integrated circuit (IC) current feedback op-amps (CFOAs; such as AD844 from Analog Devices Inc.), while the OMA-based circuits can be implemented with commercially available IC op-amps such as mA741 or LF356 in conjunction with mixed transistor arrays such as CA3096/LM3096.
This chapter presents a variety of voltage-controlled impedance realizations most of which, apart from dealing with voltage-controlled resistances, also deal with voltage-controlled capacitances, voltage-controlled, inductances and voltagecontrolled frequency-dependent negative resistance. Such voltage-controlled, impedances have been realized so far using a variety of active integrated circuit building blocks such as operational amplifiers, operational transconductance amplifiers, second-generation current conveyors and current feedback operational amplifiers. Various configurations for realizing grounded/floating, positive/ negative voltage-controlled impedance circuits have been detailed out, and some of their representative applications have been illustrated.
In this chapter, we present some prominent contributions made in the realization of gyrators and related impedances using electronic circuit building blocks of relatively more recent origin. Thus, we discuss the impedance synthesis using electronic circuit building blocks such as operational transresistance amplifier, Unity gain voltage follower/current follower, current-differencing buffered amplifier, voltage-differencing current conveyor (CC), current-differencing CC, current-differencing transconductance amplifier, current-follower transconductance amplifier, CC transconductance amplifier, voltage-differencing differential input buffered amplifier, voltage-differencing buffered amplifier and many others. Since the work on the use of all these building blocks done so far is by no means complete, we would also highlight what has not been attempted so far.
Electronically controllable resistors find numerous applications in the realization of electronically controlled amplifiers, integrators, filters, oscillators and in a number of other linear/nonlinear functional circuits. This chapter presents the significant developments made in the realization of positive and negative, grounded and floating electronically variable resistors implementable in both bipolar and CMOS technology. Salient features of the various circuits have been pointed out and some applications have been outlined.
This chapter discusses methods and circuits of producing gyrators, simulated grounded and floating inductors and transformers in both bipolar and CMOS technology. While in the case of bipolar circuits, we have included only some of the prominent configurations from amongst the available works, the treatment of CMOS circuits has been restricted to the developments taken place from 2008 onwards. Thus, the circuits and techniques prior to 2008 have been treated in a somewhat concise manner only due to the fact that more detailed treatment of these is already available in some of the recent books on this topic. Wherever possible, the applications suggested by the proposers of the concerned circuits have also been highlighted.
This chapter first presents a retrospection of the developments on gyrators, simulated inductors and other impedances as presented in the preceding ten chapters of this monograph. In doing so, we present several general conclusions about a large number of circuits discussed in this monograph and reiterate a number of unresolved problems which are open to investigation for further research. Besides this, we also outline a number of interesting developments of relatively more recent origin and also give an overview of the impact of the circuits and techniques of impedance simulation on the areas of memristive circuits and fractional-order circuits - both of which are currently being rigorously investigated in the analog circuits' literature.
