First-generation Current Conveyor Research Articles

A New Active Device Namely S-CCI and Its Applications: Simulated Floating Inductor and Quadrature Oscillators

A new active building block namely, subtractor connected first-generation current conveyor (S-CCI) is introduced in this paper. A simulated floating inductor (SFI) and two new quadrature oscillators (QOs) employing only one S-CCI are introduced as application examples. The introduced SFI employs two resistors with a single matching requirement and a grounded capacitor. Each of the introduced QOs has one grounded resistor, one floating resistor, and two grounded capacitors without any matching problems. Non-ideality analyses are performed. Furthermore, a third-order filter application is given. A layout of the S-CCI in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18 \mu \text{m}$ </tex-math></inline-formula> technology occupying the area of about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$71\,\,\mu \text{m}\,\,\times 44\,\,\mu \text{m}$ </tex-math></inline-formula> is given. Also, numerous post layout simulations based on the SPICE program are accomplished. Moreover, several experiments are realized to confirm the theory.

High-performance CMOS CCI in a 0.35 $\mu $m CMOS technology and a new all-pass filter application

A differential pair-based, high-performance, first-generation current conveyor is proposed. The proposed circuit is laid out using the Mentor Graphics IC Station layout editor. The performance characteristics have been determined from HSpice postlayout simulations using the Austria Mikro Systeme 0.35 \mu m, 3.3 V process parameters. During the simulations, \pm 1.65 V supply voltages and a 25 \mu A biasing current are used. The power consumption is about 1.12 mW. The circuit also has very high voltage swings on ports X and Y, a very small impedance value on port X, high impedance values on ports Y and Z, and high-valued current and voltage transfer bandwidths. It is shown that the presented circuit can satisfy both the low-voltage/low-power and high-frequency performance current conveyor needs of the analog circuit applications. Furthermore, 2 new all-pass filter circuits as application examples are given and a procedure that can be used to search for the opportunities that would result from the use of the modified current conveyors is presented. Some special circuit topologies and new circuit function possibilities can be obtained by redesigning circuits with modified current conveyors, which is not possible with a standard current conveyor. The proposed approach is expected to allow deeper insight into circuit synthesis using modified current conveyors.

Response Mode Detection of a Linear-Logarithmic Image Sensor Using a Current-Mode Readout Circuit

A current-mode image sensor architecture using a linear-logarithmic pixel in order to improve the dynamic range is presented. The pixel cell is based on a 3T active pixel structure with a PMOS readout transistor in the linear region of operation and a PMOS reset transistor that allows for a linear-logarithmic response. An intrascene dynamic range of 90dB is obtained with a pixel fill factor of 37%. The readout circuit is composed of a first-generation current conveyor, a current memory employed as a delta reset sampling unit, a differential amplifier used as an integrator and a dynamic comparator. The pixel response operating mode is determined in the column readout. A signal is sent to the digital processing unit as an indicator to determine the pixel response operating mode in order to allow the proper analog to digital conversion. The image lag effect observed in the pixel output current is removed by the delta reset sampling circuit. Experimental results, obtained from a test structure, are presented. The circuit was fabricated in a CMOS 0.35um process from Austria Microsystems.

A new approach for high-input impedance in voltage mode filters using first-generation current conveyor in place of second-generation current conveyor

An advantage of the second-generation current conveyor (CCII) over the first-generation current conveyor (CCI) is its high-input impedance Y terminal. Thus, CCII offers cascadable voltage mode filter realisations with little efforts. However, in case of CCI this feature is difficult to achieve. This article presents a case where the CCI is able to provide cascadability for some voltage mode filter topologies, where the CCII is not. The presented approach is applied to some filter circuits from the literature and new circuits are derived with cascadability feature. Simulations are performed to verify the theoretical results.

Parasitic compensation in CCI-based circuits for reduced power consumption

In this paper, the compensation advantage of the first-generation current conveyor (CCI) over the second-generation current conveyor (CCII) in tunable circuits is shown. For this purpose, a new floating frequency dependent negative resistor (FDNR) simulator using three CCIs is presented and employed in a third-order high-pass filter. The compensation feature of the CCI is shown for the proposed high-pass filter. As a second example, the presented compensation method is tested in a second-order band-pass filter constructed with two CCIs. Applying the proposed compensation technique, the CCI-based circuits can operate in lower biasing currents, which result in lower power consumption.

Inductor implementation using a canonical number of active and passive elements

There is quite a large number of active simulated inductor realizations in the literature, but all of these presented topologies except the recently proposed inductor simulators have either more than one active component or more than a minimum number of passive components. Two resistors and one capacitor are the required canonical number of passive elements to implement a simulated inductor. In this study, a new topology using a single minus-type modified inverting first-generation current conveyor (MICCI-) as a novel active device and a minimum number of passive elements is proposed. The MICCI- is a voltage gain-variable current conveyor (GVCC). Simulation results and non-ideal voltage and current gains effects for the proposed circuit are given.

Novel SRCOs using first generation current conveyor

This paper presents two new single-resistance-controlled-oscillators (SRCOs), that employ a single first-generation current conveyor (CC) along with one/two voltage buffer(s) and a minimum of (five) passive components. Apart from providing noninteractive controls for both frequency of oscillation and condition of oscillation, a novel feature of these circuits is that they provide voltage-mode as well as currentmode outputs explicitly from the same structures, which is not available in any of the single-CC-based SRCOs published previously.

Novel CCI-based single-element-controlled oscillators employing grounded resistors and capacitors

Novel single-element controlled oscillator circuits using two negative first-generation current-conveyors, two (or three) grounded capacitors and three (or two) grounded resistors are presented. The proposed circuits enjoy oscillation control through a single grounded passive element and independent frequency control through another single grounded passive element.

Class AB CMOS first-generation current conveyor

First-generation current conveyors are usually implemented with feedback from the x-input branch to the y-input branch to obtain the input relation of Iy = Ix. In a class AB implementation this feedback causes imprecise control of the quiescent current of the conveyor. Here we present a modified class AB circuit with significantly improved control of the quiescent current.

Current-Mode Grounded-Capacitor Single-Element-Controlled Bandpass and Lowpass Filters

New circuit configurations for realizing bandpass and iowpass current-mode second-order filters are proposed. Each configuration uses a single first-generation current conveyor, a transconductance amplifier, three grounded capacitors, and two resistors at most. The parametersω0andω0/Q0of the bandpass and lowpass realizations are not interdependent and, therefore, single element control of the bandpass and lowpass characteristics is possible. Also, the feasibility of realizing a single element current-controlled sinusoidal oscillator is considered.

Programmable Current-Conveyor-Based Oscillator Employing Grounded Resistors and Capacitors

A new programmable oscillator using two negative first-generation current-conveyors, three grounded capacitors, and two grounded resistors is presented. The proposed circuit enjoys independent oscillation control through a single grounded resistor and independent frequency control through a single grounded capacitor. Replacing one of the grounded resistors by a digitally programmable resistor results in a programmable oscillator.

Novel Current-Conveyor-Based Single-Element-Controlled Oscillator Employing Grounded Resistors and Capacitors

A novel single-element-controlled oscillator using two negative first-generation current-conveyors, two grounded capacitors and three grounded resistors is presented. The proposed circuit enjoys independent oscillation control through a single grounded resistor and independent frequency control through a single grounded resistor or a single grounded capacitor.

Applications of a first-generation current conveyor in current-mode circuits

In current-mode filter circuits which utilise a single current conveyor as the only active device, the first-generation current conveyor permits feedback of the response without connecting filter elements to the output port. Complex poles can be realised in such circuits while maintaining high output impedance. The utility of this observation is illustrated by the derivation of new second-order, complex-pole, current-mode, all-pass networks that employ a single current conveyor. Laboratory and simulation results are compared