Novel Canonic Current Mode DDCC Based SRCO Synthesized Using a Genetic Algorithm

A survey of the technical literature reveals that synthesis of Current Mode (CM) oscillators using single active building block (ABB) requires an additional identical or complementary current terminal to sense and take out the current output. The topologies of these oscillators are essentially based on the current mode approach. They use a Voltage Controlled Voltage Source (VCVS) and two current terminals to implement the CM oscillator. In the present paper, a novel DDCC (Differential Difference Current Conveyor, introduced in Chiu et al. (IEE Proc., Circuits, Devices, Syst., vol. 143, no. 2, pp. 91–96, 1996)) based canonic CM Single-Resistor Controlled Oscillator (SRCO) is presented, which uses a VCVS and a single current terminal to take out the output. Earlier, authors used DDCCC (Differential Difference Complementary Current conveyor), DVCCC (Differential Voltage Complementary Current Conveyor) to implement CM oscillators and hypothesized the requirement of an additional current terminal for the output. The synthesis of present topology indicates that DDCC is a versatile building block to implement canonic CM SRCOs and doesn't need any additional current terminal. This topology was synthesized using an innovative genetic algorithm. Spice simulations have been included and they verify theoretical results.     

MOS-C single amplifier biquads using the operational transresistance amplifier

A configuration for the realization of voltage-mode second-order filters employing a single operational transresistance amplifier (OTRA) as the active element is presented. This topology can synthesize lowpass, highpass, bandpass, notch and allpass filtering functions. The presented filters are suitable for MOS-C implementation, yielding the filter parameters to be electronically tunable. Theoretical analysis is verified with PSPICE simulation.     

Grounded-capacitor current-mode SRCO: novel application of DVCCC

An examination of the technical literature on grounded-capacitor (GC) single resistance controlled oscillators (SRCO) has revealed that no GC-SRCO has so far been published which uses only a single active building block (ABB), only two GCs and provides a current mode (CM) output with simple design equations and unconstrained tuning law. The authors not only introduce such a circuit which uses a single ABB called a `differential voltage complementary current conveyor' (DVCCC) but also indicate that a DVCCC is a versatile building block for realising SRCOs. The feasibility of the proposed formulation has been verified in PSPICE using a CMOS implementation of the DVCCC     

虚地反馈法设计GaAs HBT微波宽带VCO单片电路

给出了采用虚地和反馈等原理实现振荡器设计的方法,该方法改变了设计振荡器的传统观念,不同形式的振荡电路总是可以变成放大器和移相选频网络级联,后经反馈构成.并给出了完整的计算公式和设计过程,另外还对虚地法进行了改进,解决了设计微波振荡器电路难以找到反馈通路的困难.利用该方法成功设计了采用HBT工艺制作的宽带VCO单片电路,验证了该方法的有效性.本方法对设计VCO电路有一定的参考价值.     

New voltage controlled oscillators using CFOAs

In this paper, some new current feedback operational amplifier (CFOA)-based voltage-controlled oscillators (VCOs) have been introduced. The proposed circuits offer a number of advantageous features over previously known CFOA-based VCOs. The workability of the presented circuits has been demonstrated using AD844 CFOAs and BFW10 FETs.     

Carrier Travel Time in Transistors

A recently reported two current feedback operational amplifier (CFOA)-based oscillator is converted to a family of 16 current mode oscillators using CCII or ICCII or combination of both. A transformation method based on nodal admittance matrix (NAM) expansion is used to transform the floating capacitor CFOA-based oscillator circuit to a family of 16 grounded capacitor oscillators using CCII or ICCII or combination of both. Two of the new grounded capacitor oscillator circuits have a floating property. Simulation results are included.     

A new design topology for low-voltage CMOS current feedback amplifiers

A new topology for designing low-voltage current feedback amplifiers (CFAs) is presented. By employing a second-generation positive current conveyor followed by an operational amplifier in an unconventional manner, the design circumvents the problem of trying to achieve large transimpedance in a low-voltage environment. It is shown that this CFA configuration also results in near gain independent closed-loop bandwidth defined by a single feedback resistor. The proposed amplifier was verified experimentally by a chip designed using Taiwan Semiconductor Manufacturing Company's 0.18-/spl mu/m digital CMOS process of a single-ended power supply of 1.8 V.     

Design of Integrable Desensitized Frequency Selective Amplifiers

Synthesis procedures are presented for the synthesis of prototype frequency selective amplifiers suitable for semiconductor integrated circuit realization. Constraints and degrees of freedom imposed by semiconductor integrated passive and active components are incorporated in feedback amplifier designs. In order to achieve desensitized response, first-order pole-sensitivity functions are used in the synthesis. This leads to procedures for the simultaneous realization of prescribed response and response invariance. The procedures require feedback structures with redundant transmission-loops to provide extra degrees of freedom needed in the design. Experimental results from prototype amplifiers are presented.     

Selective Filters and Sinusoidal Oscillators Using CFA Transimpedance Pole

Using a single current feedback amplifier (CFA) device, two new variable frequency sinusoidal RC oscillators are presented. The transadmittance pole of the device (AD-844) has been utilized in the design for generating sine wave signals covering a range of 1 MHz≤f ₀≤31 MHz. Under open-loop conditions, both circuits exhibit resonance characteristics at moderate Q-values (1≤Q≤9). These responses have been experimentally verified with hardware circuit implementation and PSPICE macromodel simulation.     

Topological synthesis using Boolean algebra

This letter describes a method for synthetising the topologies of a wide class of lumped linear circuits. The method is presented by means of an example, namely the synthesis of all the minimum-element oscillators using a single positive-gain amplifier.     

Realization of n‐th Order Voltage Transfer Function Using a Single Operational Transresistance Amplifier

4 new configuration to realize the most general n‐th order voltage transfer function is proposed. It employs only one operational transresistance amplifier (OTRA) as the active element. In the synthesis of the transfer function, the RC:–RC decomposition technique is used. To the best of the author's knowledge, this is the first topology to be used in the realization of an n‐th order transfer function employing a single OTRA.     

A Realization of a Low-Voltage Differential-Output OTA Using a Simple CM Amplifier

A technique for realization of low-voltage OTAs is presented in this letter. A very low-voltage differential-output OTA is realized by employing a new common-mode amplifier in the common-mode feedback circuit. The results of PSpice simulations are shown. The proposed OTA can operate at a 0.9 V supply voltage.     

减小电容分布的单放大器开关电容带通滤波器

本文将正反馈引入到单放大器无限增益负反馈结构中,提出了四个新的带有部分正反馈的单放大器开关电容带通滤波器,得到了这些电路在给定极点频率ω_0和(?)值的设计方程和最小电容分布的最佳设计。同文献中的电路相比,本文电路的电容分布得到大幅度地减小。     

Transfer function synthesis using a finite-gain amplifier

An active RC circuit employing a single finite–gain amplifier, one two–port and two ono–ports, has been presented here for the realization of n general voltage transfer function without positive real axis zeros. The comparative merits of the scheme with respect to that proposed by Rao (1969) are that the synthesis procedure is simpler and the number of passive circuit elements required is smaller. The coefficient of realization of the synthesized transfer function can always be made equal to unity with the scheme. A few examples are included to illustrate the synthesis procedure.     

Single element controlled oscillators: A network synthetic approach

A network synthetic approach is employed for deriving a number of new circuits for single element controlled RC oscillators using a single operational amplifier.     

Realization of SRCOs: another new application of DDAs

Since the introduction of differential difference amplifier (DDA) in 1987, several CMOS implementations of the DDA have been evolved, as well as, a number of applications for realizing linear and non-linear functions using DDAs have been reported. However, to the best of authors’ knowledge, any circuit for realizing single-resistance-controlled oscillator (SRCO) using DDAs has not been reported so far. The objective of this paper is to report four new DDA-based SRCOs using DDAs, as another new application of DDAs. The workability of the derived SRCOs has been verified by PSPICE simulation as well as realizing the DDAs by commercially available video differencing amplifier AD830.     

Generation of CCII and ICCII based Wien oscillators using nodal admittance matrix expansion

This paper introduces a new generation method of the grounded capacitor Wien oscillator circuits using current conveyors (CCII) or inverting current conveyors (ICCII) or combination of both of them. The nodal admittance matrix (NAM) of the single Op Amp Wien oscillator is taken as the starting point in the new approach of systematic synthesis of equivalent oscillators. The synthesis procedure is based on the generalized systematic synthesis framework using NAM expansion. The resulting derived 32 oscillators include many novel oscillators, using current conveyors or inverting current conveyors or both. Comparison between the generated oscillators based on the effect of parasitic elements on the oscillator performance is discussed.     

On the design of CCII+ based relaxation oscillator employing single grounded passive element for linear period control

There have been an increasing number of publications on current conveyor oscillator structures in recent years. For most topologies presented, independent frequency and oscillation condition control by a single element is possible, they use minimum number of components employing grounded passive elements, but none of them allow linear period control which is essential for numerous applications. The oscillator presented here based on the nonlinear behavior of the CCII+ allows single element linear period control over three decades of the period, is suitable for integration, and is free from high frequency limitations of operational amplifier counterparts.     

Minimum component SRCO and VFO using a single DVCCC

Two oscillator topologies each employing a single differential voltage complementary current conveyor (DVCCC) are presented. The first oscillator uses a single active element, five passive components, grounded capacitors, has independent control of frequency and condition of oscillation. It has a current mode output and can be extended to provide a voltage mode output. It combines all the features of the current state-of-art oscillators. The second oscillator uses a single DVCCC, four passive elements, grounded capacitors and provides independent control of frequency. This oscillator not only has all the desired oscillator features, but requires lesser passive components. Theoretical analysis of these oscillators was verified with SPICE simulations.