Single Current Feedback Operational Amplifier Research Articles

Design of Lossless Negative Capacitance Multiplier Employing a Single Active Element

In this paper, a new negative lossless grounded capacitance multiplier (GCM) circuit based on a Current Feedback Operational Amplifier (CFOA) is presented. The proposed circuit includes a single CFOA, four resistors, and a grounded capacitor. In order to reduce the power consumption, the internal structure of the CFOA is realized with dynamic threshold-voltage MOSFET (DTMOS) transistors. The effects of parasitic components on the operating frequency range of the proposed circuit are investigated. The simulation results were obtained with the SPICE program using 0.13 µm IBM CMOS technology parameters. The total power consumption of the circuit was 1.6 mW. The functionality of the circuit is provided by the capacitance cancellation circuit. PVT (Process, Voltage, Temperature) analyses were performed to verify the robustness of the proposed circuit. An experimental study is provided to verify the operability of the proposed negative lossless GCM using commercially available integrated circuits (ICs).

Current feedback operational amplifier‐based fully orthogonal universal and multifunction filters

SummaryThis paper introduces a second‐order voltage‐mode (VM) multiple‐input single‐output (MISO) universal filter and a second‐order current‐mode (CM) single‐input multiple‐output (SIMO) multifunction filter. The introduced VM MISO universal filter includes a single current feedback operational amplifier (CFOA) and a single voltage follower as active elements, while the introduced CM SIMO multifunction filter contains two CFOAs. Both introduced circuits are orthogonally controllable. In other words, the quality factors can be controlled through a single resistor without affecting the resonance frequencies. Both circuits have low sensitivities and no passive element‐matching conditions. The introduced VM MISO universal filter has a low output impedance. Moreover, to extract the output currents of the proposed CM SIMO from high impedance terminals, second‐generation current conveyor‐based version of the circuit is introduced. Simulations are made through the PSPICE program, where 0.13‐μm IBM CMOS technology parameters are utilized. DC supply voltages are selected as ±0.9 V. In the experiments, AD844s are used, and DC supply voltages are chosen as ±7.5 V.

New negative‐grounded capacitance multiplier circuits

SummaryIn this communication, three new negative‐grounded capacitance multiplier (NGCM) circuits employing a single current feedback operational amplifier (CFOA), two resistors, and a grounded capacitor (which is most suitable for parasitic absorption and also IC implementation point of view) are investigated. No matching constraints are required for any of the proposed circuit realizations. Out of the three proposed circuits, multiplication factor of one of the capacitance multiplier can be controlled electronically as the controlling resistor is grounded, which can easily be replaced by a voltage‐controlled resistor (VCR). Error analysis of the proposed NGCMs has been carried out, and the results have been compared with those obtained from ideal analysis. To substantiate the feasibility of the proposed circuits, macro model of CFOA has been used, and the simulations have been performed in Personal Simulation Program with Integrated Circuit Emphasis (PSPICE). Simulation results for frequency analysis, Monte‐Carlo analysis, and temperature analysis have been included for the theoretical justification. Noise analysis and power supply rejection ratio analysis have also been carried out for the proposed circuits. The multiplication factors of the proposed NGCMs have been obtained up to a maximum value of 2001. The impedance and phase of the proposed NGCM structures are insensitive with temperature. The functionality of the proposed structures has also been validated experimentally using commercially available IC AD844‐type CFOA.

Single-CFOA-Single-External-Capacitor-Based Partially-Active-R SRCOs: The Fourth Missing Circuit

A new single-resistance-controlled-oscillator (SRCO) is presented which employs a single current feedback-operational amplifier (CFOA) along with four resistors but needs only a single external capacitor due to the incorporation of the CFOA-pole in the design. It provides independent control of the condition of oscillation and the frequency of oscillation through two separate resistors. To the best knowledge of the authors, this single-CFOA-based partially active-[Formula: see text] SRCO has not been reported explicitly in the technical literature earlier and hence is the fourth missing circuit of this class of SRCOs. Experimental results confirming the validity of the new proposition have been included and the comparative features of all the four circuits have been highlighted.

A novel lead and lag compensator circuit employing a single current feedback operational amplifier

In this study, a novel lead and lag type compensator circuit is proposed using a single active component, namely, the current feedback operational amplifier (CFOA). The proposed circuit has only one CFOA, two grounded resistors and two grounded capacitors. The input impedance of the proposed compensator is designed to be high whereas the output impedance is low. In terms of input and output impedance values, the proposed topology is suitable for a cascade connection with the voltage-mode structure not requiring buffer circuits, both at the input and output of the circuit. Moreover, the proposed circuit offers the advantage of controlling the poles and zeros orthogonally. The non-ideal effects depending on the active component are also presented in the paper.The commercially available AD844 integrated circuit component was used as the CFOA component in the proposed lead and lag compensator circuit and circuit simulations were performed using PSpice. Moreover, the electrical performance of the circuit was demonstrated by experimental studies. The achieved theoretical, simulation and experimental results are given with a comparison. Finally, a closed-loop control system application was given using the proposed compensator circuit and the operation of the circuit was demonstrated with PSpice simulations.

A Novel Floating/Grounded Meminductor Emulator

Meminductor is a nonlinear two-terminal element with storage energy and memory ability. To date, meminductor element is not available commercially as memristor and memcapacitor are. Therefore, it is of great significance to implement a meminductor emulator for breadboard experiment. In this paper, a flux-controlled floating/grounded meminductor emulator without a memristor is presented. It is built with commercially available off-the-shelf electronic devices. It consists of single operational transconductance amplifier (OTA), single multiplier, two second-generation current conveyors (CCIIs), single current-feedback operational amplifier (CFOA) and single operational amplifier. Using OTA device introduces an additional control parameter besides frequency and amplitude values of applied voltage to control the area of pinched hysteresis loop of meminductor. Mathematical model of proposed emulator circuit is given to describe the behavior of meminductor circuit. The breadboard experiment is performed using CA3080, AD844, AD633J and LM741 for OTA, CCII–CFOA, multiplier and operational amplifier, respectively. Simulation and experimental test results are given to verify the theoretical analyses. Frequency-dependent pinched hysteresis loop is maintained up to 5 kHz. The presented meminductor emulator tends to work as ordinary inductor for higher frequencies.

A Multifunctional Voltage Mode Fractional Order Filters using a Single CFOA

A multifunction voltage mode fractional order filter structure is described using a single current feedback operational amplifier (CFOA). This configuration realizes three fractional order filters (FOFs) namely fractional order low pass (FOLP), fractional order band pass (FOBP) and fractional order high pass (FOHP) filters. The performance of the proposed structure has been verified through PSPICE and MATLAB simulation results using macro model of AD844 type CFOA.

A Class of Single-CFOA-based Sinusoidal Oscillators

A class of second order sinusoidal oscillators is presented which employs a single Current feedback-operational amplifier, four capacitors and four to five resistors which can be realized by CMOS linear voltage controlled resistors (VCR). The proposed circuits are simultaneously single resistance controlled oscillators (SRCO) as well as single capacitor controlled oscillators (SCCO) providing independent control of condition of oscillation and frequency of oscillation through independent resistors as well as independent capacitors. To the best knowledge of the authors, any single-CFOA-based oscillators which are simultaneously SRCOs as well as SCCOs have not been reported in the literature earlier. SPICE simulation results using 0.18μm CMOS technology have been given which confirm the validity of the proposed circuits.

A voltage-mode PID controller using a single CFOA and only grounded capacitors

A new voltage-mode (VM) proportional integral derivative (PID) controller employing only a single active component named Current Feedback Operational Amplifier (CFOA), two resistors and two grounded capacitors is proposed. The proposed PID controller employs a canonical number of only grounded capacitors without requiring any critical passive component matching conditions and cancellation constraints. It has high input and low output impedances; thus, it can be easily cascaded with other VM structures. It can be easily constructed by a single commercially available active element. Frequency-dependent non-ideal gain and parasitic impedance effects on the performance of the proposed PID controller are investigated. The performance of the proposed PID controller circuit is demonstrated by using PSPICE circuit simulation program and an experiment. Also, 0.18 μm CMOS TSMC technology parameters with ±2 V supply voltages are used. Total power dissipation of the proposed PID controller is 1.64 mW.

Synthesis of New Single CFOA-Based VCOs Incorporating the Voltage Summing Property of Analog Multipliers

Recently, current feedback operational amplifier (CFOA) and analog multiplier-(AM-) based-voltage controlled oscillators (VCOs) have been published in the literature which require 2 CFOAs and 2 AMs for linear tuning law between control voltage and frequency of oscillation. In this paper, a family of eight new voltage-controlled oscillators (VCOs), with linear tuning laws, employing only a single CFOA in conjunction with two analog multipliers (AMs), has been derived through a systematic state-variable methodology. This has been made possible by exploiting the voltage summing property of the multiplier chosen which has never been done in the literature earlier. The workability of the presented VCOs has been verified by experimental results based on AD844 type CFOAs and AD534 type AMs, and the advantages of new circuits over the previously known CFOA-AM-based VCOs have been highlighted.

New grounded immittance function simulators using single current feedback operational amplifier

Using unified representations for single current-feedback operational amplifier based immittance function simulators, new circuits can be systematically discovered. In this article a catalogue of t...

Two Simple Analog Multiplier Based Linear VCOs Using a Single Current Feedback Op-Amp

Two simple voltage-controlled-oscillators (VCO) with linear tuning laws employing only a single current feedback operational amplifier (CFOA) in conjunction with two analog multipliers (AM) have been highlighted. The workability of the presented VCOs has been demonstrated by experimental results based upon AD844 type CFOAs and AD534 type AMs.

On the oscillator implementations using a single current feedback op-amp

New oscillator topologies starting from a six nodes plus ground parent network and employing a single current feedback op-amp are presented. The circuits are the results of a systematic circuit generation. Many of these circuits can easily be derived from the previously proposed circuits however four single resistance controlled circuits are found to be new. Two of them can also be realized as current feedback operational amplifier (CFOA) pole oscillator. The frequency stability properties of the presented circuits are also investigated. Furthermore a comparison of the single-resistance-controlled oscillators presented previously and in this paper employing single CFOA is given. For the new proposed oscillators experimental tests are performed to verify theory.

Current Feedback Operational Amplifier Based Oscillators

This paper demonstrates the practicality of the current feedback operational amplifier (CFOA) in realizing grounded capacitor (or grounded resistor) oscillator circuits. The paper begins with a description of the minimum passive component oscillators, using one or two CFOAs. Next, two new single CFOA oscillators with independent control on the condition of oscillation are generated from the single CFOA minimum component oscillator. Three new oscillator circuits using two CFOAs are introduced. Grounded capacitor and grounded resistor oscillators using three CFOAs with independent control on the condition of oscillation and on the frequency of oscillation are also included. The proposed grounded component oscillators are suitable for VLSI implementation. PSpice simulations and experimental results demonstrating the performance of some of the proposed oscillators are given.

A Minimum Component Grounded-Capacitor CFOA-Based RC Oscillator

A minimum-component grounded-capacitor single-frequency RC-sinusoidal oscillator circuit using the current feedback operational amplifier (CFOA) is presented. The circuit uses a single CFOA, two resistors, and two grounded capacitors. The circuit enjoys low active and passive sensitivity characteristics.