Cevdet Acar

A new versatile building block : current differencing buffered amplifier suitable for analog signal-processing filters

A new multi-terminal active component with two inputs and two outputs, namely current differencing buffered amplifier (CDBA) is proposed. It is derived from current feedback amplifier (CFA) which is commercially available as AD844. It has been shown by realising high-order voltage transfer function that it is beneficial to use this element as a building block to realize analog signal-processing filters.

Current-mode all-pass filters using current differencing buffered amplifier and a new high-Q bandpass filter configuration

A new configuration realizing first-order canonical current processing all-pass filters based on current differencing buffered amplifier, a recently introduced active element, is proposed. Using this configuration, two types of first-order current-mode all-pass filters are derived. They employ only a single active element and a bare minimum number of passive components. No component-matching constrains are required. Because of the high performance of the current differencing buffered amplifier, they are suitable for wideband applications. The derived filters are cascadable because of their high output impedances and they use fewer active and/or passive components compared to their previously reported counterparts. As an application of the proposed first-order all-pass networks, a new current-mode high-Q bandpass filter, which offers a number of advantages over its counterparts, is also given.

Single resistance-controlled sinusoidal oscillators employing current differencing buffered amplifier

Abstract The basic aim of this paper is to present several of a newly introduced current differencing buffered amplifier (CDBA)-based oscillator topologies achieving orthogonal control of oscillation condition b and oscillation frequency ω 0 with a reduced number of components. A single resistor is used for adjusting their frequency, and further, this resistance is grounded, which is important from the integration point of view. Taking these considerations into account they are very suitable for voltage-controlled oscillator (VCO) implementation.

On the realization of OTA‐C filters

A synthesis procedure based on the signal flow graph is given for generating second-order active filters using a minimum number of operational transconductance amplifiers and grounded capacitors. the pole quality factor and pole frequency sensitivities are studied for the proposed filters. Furthermore, the limitations on input signal amplitude are studied and a simple formula is derived for the input signal amplitude not causing clipping and slew-rate-limiting problems.

Realization of nth-order current transfer function using current-differencing buffered amplifiers

The authors propose two new configurations suitable for high-order filter response. It is possible to realize the most general nth-order current-mode transfer function using these configurations, involving a single or two current-differencing buffered amplifiers (CDBAs) and the RC:–RC decomposition technique. With the proposed configurations, the number of active elements is reduced to one or two, which is a significant reduction in comparision with the previously reported methods.

Quadrature Oscillator Using Current Differencing Buffered Amplifiers (CDBA)

This paper proposes a current differencing buffered amplifier (CDBA)-based quadrature oscillator (QO) circuit which has only grounded and virtually grounded capacitors, and good sensitivity properties. Oscillation frequency of this configuration can be made adjustable by using voltage controlled elements (MOSFETs). Its performance is analysed and results of circuit simulations that verify theoretical predictions are presented. Index Terms – Quadrature oscillator, CDBA, all-pass filter

A New Floating Inductor Circuit Using Differential Voltage Current Conveyors

Ein neuer Schaltkreis f r hochliegende Induktivit ten unter Verwendung von Strom bertragern mit differentiellem Spannungseingang Abstract A new floating inductor circuit is proposed using two differential voltage current conveyors and a minimum number of passive elements. Since passive elements are all grounded, this circuit is suitable for fully integrated circuit design. Moreover it does not require any element matching condition. It has a good sensitivity performance due to tracking errors. The proposed inductor circuit can be controlled through with grounded resistors.

nth-order current transfer function synthesis using current differencing buffered amplifier : signal-flow graph approach

The authors present a general synthesis method for the realisation of nth-order current transfer function using current differencing buffered amplifier which can easily be derived from a commercially available active component, AD844. The use of this active component simplifies the implementation of analogue signal processing filters and hence makes the proposed circuit attractive.

Limitations on input signal level in voltage-mode active-RC filters using current conveyors

Abstract The current conveyors (CCIIs) operate linearly under certain conditions. Violation of these conditions causes nonlinear distortion in active filters involving CCIIs. On the other hand, voltage-mode active-RC filters are considerably important in filter design. Considering these facts, a simple formula is derived for maximum input signal amplitude preventing nonlinear distortion in voltage-mode active-RC filters involving current conveyors. Derived formula are verified by SPICE simulations on chosen active filter examples. Using the formula presented in this study and the impedance scaling property, the input signal level can be optimized and the behaviour of the active filters can be improved.

Current-controllable fully-integrated inductor simulator using CCCIIs

A novel current controllable floating or grounded inductor simulator circuit with minimum elements is proposed. The circuit uses two dual output- second generation current controlled conveyors (DO-CCCIIs) with parasitic resistance at terminal X and one grounded capacitor externally connected. Proposed circuit is suitable for fully integrated circuit design. Analysis and simulation results are included.