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

doi:10.1016/S0045-7906(01)00024-6

Computers & Electrical Engineering

Volume 29, Issue 1, January 2003, Pages 45-53

https://doi.org/10.1016/S0045-7906(01)00024-6 Get rights and content

Abstract

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.

Introduction

The interest in current-mode signal processing circuits is still growing [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14]. Universal or multifunction filters are a useful class of current-mode as well as voltage-mode filters since they permit realization of different filter functions with the same topology depending on the port used. They therefore bring versatility, simplicity and cost reduction to the integrated circuit manufacturer. The current-mode universal filters may be divided into subcategories considering the input and output ports. Some filters are single-input multiple-output type (SIMO) and others are multiple-input single-output (MISO) type. For both classes low input impedance and/or high output impedance is advantageous from cascadability point of view. For certain filters signal output is obtained on a passive element thus additional active elements will be needed for those filters to sense the output signal and to cascade [1], [2], [3], [4]. For cascadability to obtain higher order filters it is preferred that the structure should exhibit high output resistance.

For the cases where power consumption is an important parameter, the number of active elements employed will be important. Some multiple output current-mode filters with fewer number of active elements realize two filter functions simultaneously [2]. This paper presents a universal filter employing only a single second generation current conveyor and is of MISO type. The filter exhibits high output impedance and is canonical in the number of capacitors and resistors. For the cascade implementations to obtain high-even-order filters the number of active elements will only be equal to n/2, where n is the order of the filter.

Section snippets

Actual second generation current conveyor

The non-inverting current conveyor CCII+ is illustrated in Fig. 1. Its terminal relationship can be given as $V_{X} =V_{Y}, I_{Y} =0, I_{Z} =I_{X}$ Considering the non-idealities arising from the physical implementation of CCII+ its terminal relationships are modified to $V_{X} =βV_{Y}, I_{Y} =0, I_{Z} =αI_{X}$ where α and β are, respectively, current and voltage gains which can be expressed as α=1−ϵ_i, β=1−ϵ_v, with |ϵ_i|≪1, |ϵ_v|≪ 1; ϵ_i denotes the current tracking error and ϵ_v denotes voltage-tracking error, respectively. Another important

Proposed filter topology

The general form of the universal filter topology proposed is illustrated in Fig. 2. Setting the currents i₁=i₃=0 and applying an input current of i₂ to the circuit, a low-pass filter function can be obtained which is described by $i_{out} i_{2} = G_{2} G_{1} s^{2} C_{1} C_{2} +sG_{2} C_{1} +C_{2} +G_{2} G_{1}$ Taking the currents i₂=i₁=0 and applying an input current of i₃ to the circuit, a band-pass filter function is obtained. The BP transfer function is given by $i_{out} i_{3} = −sC_{1} G_{1} s^{2} C_{1} C_{2} +sG_{2} C_{1} +C_{2} +G_{2} G_{1}$ Providing the conditions $i_{2} =−i_{1}$ and $i_{3} =i_{1} G_{2} C_{1} +C_{2} G_{1} C_{1}$

Simulation results and discussion

To verify the above given theoretical analysis, multifunction filters realizing Butterworth characteristic with unity gain and a pole frequency of f₀≅225 kHz are designed using the proposed configuration of Fig. 2 with passive element values R₂=0.5 k $Ω$ , R₁=1 k $Ω$ , C₁=1 nF, C₂=1 nF for all type second-order filters. The active element used in this design is the commercially available CFOA AD844/AD of Analog Devices. The circuit was supplied with symmetrical voltages of V_DD=12 V and V_SS=−12 V.

Conclusion

A current mode MISO multipurpose filter configuration is proposed using CCII+ or CFOA as active component, which is suitable for high performance analog signal processing. Note that the proposed filter uses a reduced number of passive and single active elements, namely two resistors, two capacitors, as well as one CCII+ or CFOA. LP and BP filters do not require any matching condition, HP filter configuration does require a simple matching condition, which is quite important in mass production.

Sadri Özcan received his B.Sc., MSc., and Ph.D. degrees from İstanbul Technical University in 1971, 1974 and 1989, respectively. In 1973 he joined as research assistant to the Electronics and Communication Engineering Department of Electrical and Electronics Faculty of İstanbul Technical University. Since 1993 he is a Associate Professor in the Same department. He teaches Electronic Devices and Components, Analog electronics, Digital electronics. His research interests include the active

References (15)

M. Higashimura
Current-mode lowpass, bandpass and highpass filters using an FTFN
Microelectron J
(1993)
M.T. Abuelma'atti et al.
A novel current-conveyor-based universal current-mode filter
Microelectron J
(1996)
E.O. Güneş et al.
Realization of current-mode universal filter using CFCCIIps
Electron Lett
(1996)
C.M. Chang
Current-mode lowpass bandpass and highpass biquads using two CCIIs
Electron Lett
(1993)
A. Fabre et al.
Universal current-mode biquad implemented from 2 2nd generation current conveyors
IEEE Trans Circuits Systems. I. Fundamental Theory Appl
(1995)
R. Senani
New current-mode biquad filter
Int J Electron
(1992)
C.M. Chang
Novel universal current-mode filter with single-input and 3 outputs using only 5 current conveyors
Electron Lett
(1993)

There are more references available in the full text version of this article.

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In this section, a comparison of a recently reported similar type multi-input single-output (MISO) current-mode biquadratic filter and the proposed circuit is described. Over the last decade, several current-mode MISO-type universal biquadratic filters using a single high-performance active element have been reported in [10–26]. However, for certain filters in [10,11]], both BP and HP output signals are obtained on the grounded capacitors, and thus some extra buffers are needed for those filters to sense the output signals.
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Oğuzhan Çiçekoğlu was born in 1963 in İstanbul, Turkey. He received the B.Sc., and M.Sc. degrees from Boğaziçi University and the Ph.D. degree from İstanbul Technical University all in Electrical and Electronics Engineering in 1985, 1988 and 1996, respectively. He served as teaching assistant in Computer Engineering Department, as lecturer at the School of Advanced Vocational Studies Electronics Prog. of Boğaziçi University where he held various administrative positions between 1993 and 1999, and as part time lecturer at various institutions. He is currently Associate Professor at the Biomedical Engineering Department of Boğaziçi University. His current research interests include analog circuits, active filters, analog signal processing applications and current-mode circuits. He is the author or co-author of more than 80 papers published or accepted for publishing in scientific journals or conference proceedings. Oğuzhan Çiçekoğlu is a member of the IEEE.

Hakan Kuntman was born in İstanbul, Turkey, 1949. He received his B.Sc., M.Sc. and Ph.D. degrees from İstanbul Technical University in 1974, 1977 and 1982, respectively. In 1974 he joined the Electronics and Communication Engineering Department of İstanbul Technical University. Since 1993 he is a professor of electronics in the same department. His research interest include design of electronic circuits, modelling of electron devices and electronic systems, active filters, design of analog IC topologies. He is the author or the coauthor of 57 journal papers published or accepted for publishing in international journals, 56 conference papers presented or accepted for presentation in international conferences, 66 turkish conference papers presented in national conferences and 10 books related to the above mentioned areas.

¹: Tel.: +90-263-1540/1338; fax: +90-212-265-9813.

²: Tel.: +90-212-285-3647; fax: +90-212-285-3679.

View full text

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

Abstract

Introduction

Section snippets

Actual second generation current conveyor

Proposed filter topology

Simulation results and discussion

Conclusion

Microelectron J

Microelectron J

Realization of current-mode universal filter using CFCCIIps

Electron Lett

Current-mode lowpass bandpass and highpass biquads using two CCIIs

Electron Lett

Universal current-mode biquad implemented from 2 2nd generation current conveyors

IEEE Trans Circuits Systems. I. Fundamental Theory Appl

New current-mode biquad filter

Int J Electron

Novel universal current-mode filter with single-input and 3 outputs using only 5 current conveyors

Electron Lett