Current-mode Multifunction Filter Research Articles

A Modern VDCCTA Active Element and Its Electronic Application

In this paper, a novel current mode (CM) building block termed Voltage differencing current conveyor transconductance amplifier (VDCCTA) is developed by combining the voltage differencing current conveyor (VDCC) and an operational transconductance amplifier (OTA). This modern active block VDCCTA is extended for applications such as a lossless inductor, filter design, and chaotic circuit design. An active inductor simulator (AIS) without any component matching is designed using the proposed VDCCTA block and a grounded capacitor as a first application that offers flexibility to model grounded positive active inductor (GPAI), grounded negative active inductor (GNAI), and floating positive active inductor (FPAI) circuits. Moreover, the proposed positive active inductor (PAI) can also be translated for multiple input single output (MISO) voltage mode (VM) universal filter with two external passive elements and chaotic circuitry. The characteristics of VDCCTA are verified with the CM multifunction filter, VM band-pass filter, and VM-MISO filter. A complete exercise of this newly reported VDCCTA block is analyzed for their port characteristics validation and the performance parameters using PSPICE simulation. Finally, experimental verification of the proposed AIS is tested to justify the theoretical and simulated results.

Realization of Generalized Current-Mode Multifunction Filter

In this work, a three-input single-output structure of current-mode second-order multifunction filter is presented. Two multiple-output second-generation current conveyors serve as the active building blocks. Additionally, two grounded resistors and two grounded capacitors are employed as passive components. On appropriate selection of the input values, all second-order filter functionalities, namely, low-pass, high-pass, all-pass, band-pass and band-reject, can be availed. Proposed filter shows good sensitivity performance and supports high frequency operation. Non-ideal analysis is presented to show the intactness of filter characteristics under runtime conditions. Simulation results show good correlation with the theoretical performance of the proposed filter.

An active inductor employing a new four terminal floating nullor transconductance amplifier (FTFNTA)

ABSTRACTIn this scientific study, a new analog active building block named as four terminal floating nullor transconductance amplifier (FTFNTA) is implemented. The FTFNTA design offers a combined essence of both traditional four terminal floating nullor (FTFN) and an operational transconductance amplifier (OTA). The FTFNTA design is extended for the design of a lossless floating and grounded inductor simulator with few passive components. In addition, the performance and usefulness of the proposed inductor topology are also expanded for active filter applications: higher-order Butterworth high-pass filter and current mode multifunction filter. The functionality of the CMOS-based FTFNTA is integrated with a 0.18 µm Taiwan Semiconductor Manufacturing Company (TSMC) CMOS technology. Moreover, the FTFNTA is also realised using the current feedback operational amplifier (CFOA/AD844) and OTA (OTA/CA3080) of a commercially available IC to test the viability of the proposed inductor design. Finally, an application based on the inductor topology and its impedance characteristics are well analysed via PSPICE simulation.

Novel CMOS Dual-X Current Conveyor Transconductance Amplifier Realization with Current-Mode Multifunction Filter and Quadrature Oscillator

This paper presents a novel active element, namely dual-X current conveyor transconductance amplifier. The CMOS implementation, parasitic model and characteristic performance parameters of the proposed dual-X current conveyor transconductance amplifier have been explored. The proposed active element has the advantages of good operational bandwidth, good dynamic range and low power consumption. Additionally, current-mode multifunction filter and quadrature oscillator are proposed to examine the applicability of the newly proposed active element. The proposed current-mode multifunction filter provides the responses, low-pass, high-pass and band-pass simultaneously without any circuit modification. The proposed quadrature oscillator circuit simultaneously generates three current outputs and three voltage outputs. The non-ideal analyses of both current-mode multifunction filter and quadrature oscillator are also included. Moreover, the active and passive sensitivities of both current-mode multifunction filter and quadrature oscillator are calculated which are found to be less than unity in magnitude. HSPICE simulation results are depicted to confirm the theoretical analyses. Moreover, practicality of novel dual-X current conveyor transconductance amplifier is examined through the experimental results of the proposed quadrature oscillator.

Minimum passive components based lossy and lossless inductor simulators employing a new active block

In this paper a new active element namely Dual X current conveyor differential input transconductance amplifier (DXCCDITA) is proposed. The DXCCDITA is utilized in designing eight topologies of lossy and lossless grounded inductor simulators and two topologies of floating inductor simulators. All the designed grounded simulators require only two passive elements and a single active block. The two floating inductor simulators require a single active block and one or three grounded passive elements. In addition, all the designs make use of only grounded capacitors for implementation which is advantageous for fabrication. All the proposed active inductors, except two, did not require any component matching conditions for realization and all the inductor simulators are perfectly tunable. The effect of non-idealities on the proposed grounded simulator structures is also studied. To demonstrate the workability of the inductor simulators they are used in design of second order low pass filter, parallel RLC resonance circuit, third order Butterworth high pass filter, parallel RLC current mode multifunction filter and a voltage mode band pass filter. The DXCCDITA is implemented in 0.35μm TSMC CMOS technology parameters and tested in Tanner EDA. Sufficient number of simulations are provided to establish the functionality of the active inductor structures.

Signal Flow Graph Synthetical Implement the Current-Mode Multifunction Filter Based on CDTA

In this paper, a signal flow graph structure of current-mode multifunction filter using current differencing transconductance amplifier (CDTA) is presented. The proposed configuration is comprised of two grounded capacitors and four CDTAs. They exhibit low-input and high-output impedances, which is very convenient for integrated circuit implementation. The presented filter configuration can realize all the standard filter functions simultaneously, lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP), without any component matching conditions. The natural frequency () and the bandwidth () of the proposed filter can be electronically tuned by varying the bias current of the CDTA. PSPICE simulation results are included to confirm the theory.

CDTAs based Current-Mode Multifunction Filter Employing Grounded Capacitors

In this paper, a new current-mode multifunction filter based on current differencing transconductance amplifier(CDTA) is presented. The proposed filter employs two current differencing transconductance amplifier (CDTA) and only two passive elements to realize lowpass and bandpass filter functions. The proposed filter have been tested with PSPICE simulation program. PSPICE simulation result confirms the theoretical analysis. The active and passive sensitivities are quite low General Terms Analog Filters , Active Building Blocks

Cascadable Current-Mode First-Order and Second-Order Multifunction Filters Employing Grounded Capacitors

A configuration for realizing low input and high output impedances current-mode multifunction filters using multiple output second-generation current conveyors (MOCCIIs) is presented. From the proposed circuit configuration, first-order allpass, highpass, lowpass and second-order allpass, notch, bandpass filters can be obtained. The simulation results confirm the theoretical analysis.

Novel low-voltage low-power high-precision CCII± based on bulk-driven folded cascode OTA

This paper presents possible approaches to the design of a novel low-voltage, low-power, and high-precision current conveyor of the second generation (CCII±) based on the bulk-driven folded cascode operational transconductance amplifier (OTA) with extended input common-mode voltage range. This CCII± utilizes bulk-driven differential pairs to obtain a nearly rail-to-rail input stage at a low supply voltage. The proposed conveyor operates at a low supply voltage of ±400mV with a reduced power consumption of only 64μW. A current-mode multifunction filter is presented as an application of the CCII±. This filter provides five transfer functions simultaneously, namely low-pass, band-pass, high-pass, notch, and all-pass. The filter has the following properties and advantages: it employs three bulk-driven current conveyors BD-CCII±, three grounded resistors, and two grounded capacitors, which is suitable for integrated circuit implementation. Furthermore, the input signal is connected to the low-impedance X terminal of the BD-CCII± whereas the output signals are taken from the high-impedance output terminals Z+ and Z−. Finally, the pole frequency and quality factor of the designed filter are tunable independent of each other. PSpice simulation results using the 0.18μm CMOS technology are included to prove the results.

Voltage/Current-Mode Multifunction Filters Using One Current Feedback Amplifier and Grounded Capacitors

One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions; low active and passive sensitivities; employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.

New lossless inductance simulators realization using a minimum active and passive components

In this paper, five new lossless grounded inductance simulators are presented. All proposed inductor simulator circuits employ with only a single Fully Differential Second-Generation Current Conveyor (FDCCII), two resistors and a capacitor are proposed. Moreover, all passive components are grounded therefore the proposed inductance simulator circuits offer ease of integration and tuning advantages with low sensitivities. To demonstrate the performance of the proposed FDCCII-based inductance simulators, we use one of the circuits to construct a current-mode multifunction filter. The proposed inductance simulator circuits and current-mode multifunction filter are simulated with SPICE program. Simulation results are given to verify the theoretical analysis.

Voltage/Current-Mode Multifunction Filters Using Current-Feedback Amplifiers and Grounded Capacitors

One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters each using two current-feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibits simultaneously lowpass, bandpass, and highpass filters. The proposed current-mode circuit also exhibits simultaneously lowpass, bandpass, and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions, low active and passive sensitivities, employing only grounded capacitors, and the ability to obtain multi-function filters from the same circuit configuration.

Current-tunable current-mode multifunction filter based on dual-output current-controlled conveyors

In this paper, a current-tunable current-mode multifunction filter with two inputs and two outputs employing only four dual-output current-controlled conveyors (DO-CCCIIs) and two grounded capacitors is proposed. By appropriately connecting the input and output terminals, the proposed circuit can provide lowpass, bandpass, highpass, bandstop and allpass current responses. The filter also offers an independent electronic control of the natural frequency ( ω o ) and the quality factor ( Q) through adjusting the bias currents of the DO-CCCIIs. No critical matching conditions are imposed for realizing all the filter responses, and all the incremental parameter sensitivities are low. The characteristics of the proposed circuit are simulated using PSPICE to confirm the theory.

Current mode multifunction filter using two CDBAs

This paper presents a cascadable current-mode (CM) multifunction biquadratic filter. The proposed circuit realizes all five different filter transfer functions employing only two current differencing buffered amplifiers (CDBAs), while previously reported CM multifunction filters require more CDBAs and more passive component count for the same number of filter transfer function realizations. Examples for different filter transfer functions are given along with the results of circuit simulations. It is shown that theoretical and simulation results are in good agreement.

High impedance voltage- and current-mode multifunction filters

This paper presents a voltage- and current-mode multifunction filters based on and employing two four-terminal floating nullors (FTFNs) and a single operation transconductance amplifier (OTA). The high-input impedance voltage-mode configuration can simultaneously realize lowpass (LP), bandpass (BP) and notch filtering functions from the same configuration. The circuit employs two grounded capacitors which suits contemporary IC design techniques. The resonance frequency ω 0 and bandwidth ω 0 / Q can be independently tuned while as resonance frequency ω 0 and quality factor Q are orthogonally controllable. The current-mode configuration can simultaneously realize LP and highpass (HP) from which notch filtering signal can also be obtained. The input impedance of the circuit is very low while the output currents are available at very high impedances. The resonance frequency ω 0 and bandwidth ω 0 / Q can be orthogonally tuned. The high impedance of both the topologies in the two modes facilitates easy cascading for higher-order filter construction. Passive sensitivity figures are low. PSPICE simulation results are also included.

New Realizations of Current-Mode and Voltage-Mode Multifunction Filters without External Passive Elements

Abstract In this paper new voltage-mode and current-mode multifunction filters using internally compensated operational amplifiers (OP-AMPs) and single output operational transconductance amplifiers (OTAs) are presented. The proposed voltage mode multifunction filter can realize lowpass, bandpass, highpass responses simultaneously and the current-mode multifunction filter can realize lowpass, bandpass, highpass and bandstop responses simultaneously all at high output impedances. No external passive elements are required thus the circuit is suitable for monolithic implementation either with CMOS or bipolar technologies. All of active sensitivities are low. The performances of the circuits are tested using SPICE simulation program.

Novel Grounded Parallel Immittance Simulator Topologies Employing Single OTRA

Abstract In this study, six novel grounded parallel immittance simulator topologies employing single OTRA are proposed. Some of the presented topologies require fewer passive components than the counterparts in the literature. The proposed new immittance simulator topologies provide further possibilities for the designers in the realization of filters, oscillators and cancellation of parasitic elements. The performance of the proposed immittance simulators is demonstrated on a current-mode multifunction filter. PSPICE simulation results are included to verify theory.

Multi-input single-output filter with reduced number of passive elements employing single current conveyor

A new biquadratic universal filter configuration realising second-order low-pass, band-pass, and high-pass functions employing single current conveyor is proposed. Using this configuration high-pass, low-pass and band-pass filters can be realized with little modifications. The circuit employs a second-generation current conveyor (CCII+), and only four passive components. Since the current conveyor is a high performance active element, the circuit proposed is suitable for wide band applications. The derived filters can be easily cascaded and use reduced number of passive components compared to previously reported counterparts. To illustrate the design possibilities provided by the introduced circuit current mode multifunction filters are constructed and tested.

Wide Dynamic Range High Output Impedance Current-mode Multifunction Filters with Dual-output Current Conveyors

Summary This paper reports five new single-input multiple-output current-mode multifunction filter circuits which can simultaneously realise three basic filter functions all at high impedance outputs. The circuits employ only the same type of active elements, grounded passive components, andno element matching conditions are imposed. The filters permit orthogonal adjustment of the quality factor Q and angular resonant frequency ω 0 . The active/passive sensitivities are shown to be low.

Current-Mode High Output Impedance Multifunction Filters Employing Minimum Number of FTFNs

In this study, five current-mode FTFN-based multifunction filters are proposed, which realize the same transfer functions in ideal case. All circuits employ two capacitors and three resistors. For each circuit R-C:C-R transformation increases the number of realization possibilities to ten. The proposed topologies simultaneously realize three basic filtering functions using minimum number of FTFNs and provide high output impedances that enable easy cascading in current mode. Sensitivity analysis of the filters show that they have low passive sensitivities, \omega_0, Q and \omega_0/Q of the filters are insensitive to current tracking errors, furthermore \omega_0 of the filters are insensitive to voltage tracking errors of the FTFNs. The proposed circuits do not require component matching condition except for notch and allpass responses and permit independent adjustment of \omega_0 without disturbing \omega_0/Q. Experimental and simulation results are given to verify the theoretical analyses.