Hybrid current conveyoroperational amplifier circuit

A high-performance hybrid transconductance amplifier circuit implemented in both inverting and non-inverting configurations is described. The circuit is based on an operational amplifier–current conveyor arrangement that produces greater accuracy than other circuit configurations.     

Logarithmic current electrometer using commercially available Current conveyor AD844

Logarithmic current measurements have been made with log ratio amplifier using commercially available current conveyor AD844. The proposed circuit is designed to measure currents from 1?μA to 0.1?mA. Temperature compensation is achieved using the thermistor technique in the temperature range 25–70°C. Variations in the scale factor as a function of the input current is also discussed.     

Current conveyor based electrometer

A current conveyor based electrometer is designed to improve the frequency response of the electrometer. The input current is current amplified by a current conveyor. Current conveyor is realized by operational amplifier/resistor configuration. The circuit has been tested for two set of resistor values in the circuit for the same current gain to improve the current range towards lower current range. The frequency response is improved by a current gain factor.     

Two digitally programmable gain amplifiers based on current conveyors

Two digitally programmable gain amplifiers based on current conveyors (CCIIs) are presented. The first digitally programmable gain amplifier consists of a CCII, an operational transconductance amplifier (OTA), and current mirrors. The second one is composed of current conveyor analogue switches (CCASs). Both proposed digitally programmable gain amplifiers do not need switches but they maintain the linear gain at any digital signal levels similar to the digitally programmable gain amplifier using switches; hence the proposed amplifiers are easier to realize, use narrower chip area, and consume lower power. The first proposed amplifier is verified by constructing the circuit using the CCII in an AD844 IC, the OTA in a CA3080 IC, and some bipolar current mirrors. The second proposed amplifier is verified by simulating the circuit using the parameters extracted from the layout (including parasitic capacitance) in the 0.25 μm MOS technology, the level 49 MOS model obtained through MOSIS is used. The results show that the operations of two proposed amplifiers are in accordance with the theories.     

New precision rectifier circuits with high accuracy and wide bandwidth

Two new circuits for precise full-wave rectification are presented. The first is based on a current feedback amplifier with a new current-mode absolute-value circuit in its feedback loop. The second utilizes an operational conveyor working in conjunction with a current-mode absolute-value circuit in a new configuration. Both circuits have high accuracy and wide bandwidth, giving undistorted rectified waveforms up to 500?kHz in the first case and 1?MHz in the other. Additionally, both systems have high sensitivity, being able to full-wave rectify signals with amplitudes as small as 5?mV peak at 100?kHz. Finally, the new systems have excellent temperature stability, low offset output voltage and are suitable for IC fabrication.     

Novel low-voltage ultra-low-power DVCC based on floating-gate folded cascode OTA

In this paper a novel low-voltage ultra-low-power differential voltage current conveyor (DVCC) based on folded cascode operational transconductance amplifier OTA with only one differential pairs floating-gate MOS transistor (FG-MOST) is presented. The main features of the proposed conveyor are: design simplicity; rail-to-rail input voltage swing capability at a low supply voltage of ±0.5 V; and ultra-low-power consumption of mere 10 μW. Thanks to these features, the proposed circuit could be successfully employed in a wide range of low-voltage ultra-low-power analog signal processing applications. Implementation of new multifunction frequency filter based on the proposed FG-DVCC is presented in this paper to take the advantages of the properties of the proposed circuit. PSpice simulation results using 0.18 μm CMOS technology are included as well to validate the functionality of the proposed circuit.     

A Novel Hybrid Active Inductor

In this brief, a novel hybrid inductor is proposed. The circuit is a hybrid of an operational amplifier and a current conveyor with three passive elements, and offers advantages over conventional current conveyor implementations in its ability to produce high quality factor inductors. Experimental and PSPICE simulation results are presented which verify the theoretical derivations.     

Transformation of Voltage Mode Filter Circuit Based on Op-Amp to Circuit Based on CCII

In this paper, firstly we demonstrate the use of nodal admittance matrix to convert a low-pass band-pass filter based on operational amplifier (op-amp) to a circuit based on a second-generation current conveyor (CCII). This technique allows us to get eight presumptions of filter circuits. Secondly, we present a novel architecture circuit of CCII, which can operate at low supply voltage of 0.75 V. All simulations are performed by TSPICE models. The simulation results show that this circuit has a low impedance at terminal X (RX=1.01 ), a very high input impedance at terminal Y, and wide bandwidth current and voltage. The center frequency of the proposed filter is variable on the interval[157 kHz, 196 MHz].     

Operational floating conveyor

A new versatile analogue building block is described, termed an operational floating conveyor (OFC). The OFC has similar transmission properties to the current conveyor and current-feedback operational amplifier, but with a differential current output which allows accurate output current sampling. This feature improves circuit building block versatility and allows accurate closed loop current amplifiers and current convertors to be realised, including a closed loop current conveyor.<>     

电流传输器模拟电感的设计及其在振动控制中的应用

通过电流型运算放大器组成第二代电流传输器与RC元件实现模拟电路的设计,由此搭建压电分流阻尼系统控制机械结构振动.通过软件仿真测试模拟电感电路设计的正确性,并以根部粘贴压电陶瓷片的固支梁结构为例,对该结构的第三阶模态振动控制进行了实验研究和分析,结果表明:所设计的新型压电分流电路具有良好的减振效果.     

A Compact and Low-Power CMOS Circuit for Fully Integrated NEMS Resonators

This brief presents a fully integrated nanoelectromechanical system (NEMS) resonator, operable at frequencies in the megahertz range, together with a compact built-in CMOS interfacing circuitry. The proposed low-power second-generation current conveyor circuit allows detailed read-out of the nanocantilever structure for either extraction of equivalent circuit models or comparative studies at different pressure and dc biasing conditions. In this sense, extensive experimental results are presented for a real mixed electromechanical system integrated through a combination of in-house standard CMOS technology and nanodevice post-processing by nanostencil lithography. The proposed read-out scheme can be easily adapted to operate the nanocantilever in closed loop operation as a stand-alone NEMS oscillator     

A differential-input,differential-output current mode operational amplifier

A current operational amplifier with differential input and differential output is described. The amplifier is based on the parallel connection of a CCII+ current conveyor and a CCII? current conveyor followed by a differential output transconductance gain stage. The performance of the amplifier is analysed and experimental results obtained from an implementation using standard operational amplifiers and current mirrors realized using transistor arrays are presented and compared to the theoretical analysis. It is concluded that the static small signal open loop gain and the frequency response matches the performance of conventional voltage operational amplifiers. The input offset and bias errors and the common mode rejection are shown to be strongly dependent on the matching accuracy of the current mirrors used in the conveyors. The proposed configuration can easily be integrated into a monolithic amplifier in either CMOS or bipolar technology.     

Voltage-mode universal filter with one input and five outputs using DDCCTAs and all-grounded passive components

This paper presents a versatile voltage-mode universal active filter with one input and five output terminals. The proposed circuit is based on using the recently reported active building block, namely differential difference current conveyor transconductance amplifier (DDCCTA). It employs two DDCCTAs as active elements together with two resistors and two capacitors as passive elements, which are all grounded. The circuit simultaneously realizes all the five standard biquadratic filter functions; i.e., lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP), without changing circuit topology. The proposed circuit also has the advantage of high-input impedance terminal, and exhibits electronic tunability of its important parameters through the bias current of the DDCCTA as well as low sensitivity performance. PSPICE simulations using 0.5 μm MIETEC CMOS process are used to validate the theoretical predictions.     

Low voltage,high CMRR,and wide bandwidth novel current mode current controlled instrumentation amplifier

In this paper, a new current controlled instrumentation amplifier structure is proposed. The introduced circuit uses three current controlled conveyors and a single grounded resistor. This structure offers several enhanced advantages in comparison with other current and voltage modes instrumentation amplifiers. It provides attractive features such as: wide bandwidth independent to the differential gain, current tuned gain, high common mode rejection ratio without requiring matched resistors and low supply voltage equal to ±0.75 V. Accordingly, the proposed amplifier is a suitable element for integrated circuit implementation in the medical field. The used second-generation current controlled conveyor has a very simple structure. It is generally constituted of two NPN and seven CMOS transistors and it has numerous interesting characteristics. Theoretical analysis is carried out taking into consideration the non-ideality parameters of the conveyors. The circuit features are corroborated via a PSPICE simulation; the results are also compared to those of the previous structures presented in the literature.     

Novel chaotic oscillator configuration using a diode-inductor composite

A general sinusoidal oscillator configuration is designed and then modified for chaos using a second-order nonlinear grounded diode-inductor composite. The configuration has an operating frequency that can be electronically tuned by varying the gain of an inverting amplifier stage. In addition to this amplifier, a single positive-type second generation current conveyor (CCII+), two noninverting integrators and two grounded resistors are required. The case where one of the integrators is replaced with an all-pass filter is investigated. Since the configuration is designed at a functional level, different circuit realizations are possible. Experimental results and PSpice simulations of a constructed implementation based on current feedback op amps are included. Numerical simulations of the derived chaotic mathematical models using a piecewise linear approximation of the diode current-voltage characteristics are also shown.     

New Fully‐Differential CMOS Second‐Generation Current Conveyer

This paper presents a new CMOS fully‐differential second‐generation current conveyor (FDCCII). The proposed FDCCII is based on a fully‐differential difference transconductor as an input stage and two class AB output stages. Besides the proposed FDCCII circuit operating at a supply voltage of ± 1.5 V, it has a total standby current of 380 µA. The applications of the FDCCII to realize a variable gain amplifier, fully‐differential integrator, and fully‐differential second‐order bandpass filter are given. The proposed FDCII and its applications are simulated using CMOS 0.35 µm technology.     

Current-controlled translinear impedance converter

A current-controlled impedance converter is described which is implemented using two translinear active devices: a current conveyor with unity gain and an adjustable differential current-mode amplifier. It has low parasitic input impedance and useful properties when the amplifier gain is near unity. To characterize the circuit, SPICE simulation results are given and discussed.     

一种基于CMOS CCDVCC Ⅱ的可编程多功能滤波器及可编程测量放大器

介绍了一种新型的电调谐差分电压输入第二代电流传输器.并且用其构成一种电压模式多功能滤波器,可以获得:低通、高通、带通、带阻、全通传输函数.且这种滤波器可以通过调节电流传输器偏置电流独立改变传输函数的品质因素和固有频率.这种多功能滤波器仅仅使用两个CCDVCCⅡ、一个电阻和两个电容构成,且不需要任何元件匹配.而且,可以利...     

CMOS fully differential second-generation current conveyor

The design of a CMOS fully differential second generation current conveyor is presented. The proposed circuit was designed to incorporate the current sensing technique into a fully differential version of a differential difference amplifier (DDA). A low power class AB circuit realisation has been implemented in 1.2 μm CMOS technology. A variable gain amplifier (VGA) designed to incorporate the circuit has been shown to exhibit constant, low power consumption and constant, wide bandwidth at different gain settings. Experimental results of the proposed circuits are presented     

一种新型的宽线性范围差分电压输入电流传输器及其应用

设计了一种带有共模检测电路的宽线性范围差分电压输入电流传输器(DVCCⅡ).所提出的电路具有动态的长尾电流的差分对,可获得较大的动态线性输入范围.所提出的电路可以得到精确跟随特性和宽线性输入范围,且比较已有电路具有低电压低功耗等特点.采用SMIC 0.18μm工艺,用Spectre对电路进行仿真,电源电压是1.8 V,...