Adjustable band-pass filter with current active elements: two fully-differential and single-ended solutions
Four adjustable band-pass filtering solutions are presented and also compared in this paper. Two of them are suitable for single-ended signal processing and the other two are their fully-differential equivalents. Filters are built with two types of active elements. First is a simple current follower with multiple outputs and second is a current amplifier with adjustable current gain that is used to control the quality factor of each of filters. Dependency between gain and quality factor is direct in two cases or inverse in other cases and that is why the range of adjustability varies. Simulations with CMOS-transistor structures are included. Values of quality factor obtained for each of solutions are assessed.
KeywordsCurrent-mode Current follower Current amplifier DACA Fully differential Single ended
Authors would like to thank referees for the detailed reviews and hints that helped to improve this paper. Authors would also like to thank Editor for choosing this paper for this Special Issue. The research described in this paper was supported by Czech Science Foundation, project No. 102/09/1681, and by project No. CZ.1.07/2.3.00/20.0007 (WICOMT) that is financed by European Social Fund and Ministry of Education, Youth and Sports of Czech Republic.
- 3.Herencsar, N., Koton, J., & Vrba, K. (2009). Differential-input buffered and transconductance amplifier (DBTA)-based new trans-admittance- and voltage-mode first-order all-pass filters. In 6th International conference on electrical and electronics engineering (ELECO 2009) (pp. 256–259).Google Scholar
- 4.Mahmoud, S. A. (2004) Low voltage fully differential CMOS current feedback operational amplifier. 47th IEEE Midwest International Symposium on Circuits and Systems (MWSCAS 2004), 1, 49–52.Google Scholar
- 8.Soliman, A. M., & Mahmoud, S. A. (2009). New CMOS fully differential current conveyor and its application in realizing sixth order complex filter. In IEEE international symposium circuits and systems (ISCAS 2009) (pp. 57–60).Google Scholar
- 9.Sobhy, E. A., & Soliman, A. M. (2010). Realizations of fully differential voltage second generation current conveyor with an application. International Journal of Circuit Theory and Applications, 38(5), 441–452.Google Scholar
- 12.Jerabek, J., Sotner, R., & Vrba, K. (2010). Fully-differential current amplifier and its application to universal and adjustable filter. In 2010 International conference on applied electronics (AE 2010) (pp. 141–144).Google Scholar
- 15.Koton, J., Herencsar, N., Jerabek, J., & Vrba, K. (2010). Fully differential current-mode band-pass filter: Two design solutions. In 33rd international conference on telecommunications and signal processing (TSP 2010) (pp. 1–4).Google Scholar
- 16.Jerabek, J., Vrba, K., & Jelinek, M. (2011). Universal fully-differential adjustable filter with current conveyors and current amplifier in comparison with single-ended solution. In 2011 International conference on applied electronics (AE 2011) (pp. 189–192).Google Scholar
- 17.Sun, B., & Yuan, F. (2002). New low-voltage fully-balanced wide-band differential CMOS current amplifier. 2002 45th Midwest Symposium on Circuits and Systems (MWSCAS 2002), 2, II-57–II-60.Google Scholar
- 18.Jerabek, J., & Vrba, K. (2011). Design of fully-differential filters with nth-order synthetic elements and comparison with single-ended solution. In 2011 International conference on computer and communication devices (ICCCD 2011) (pp. V1-48–V1-52).Google Scholar
- 20.Alzaher, H. A., Tasadduq, N., Al-Ees, O., & Al-Ammari, F. (2011). A complementary metal-oxide semiconductor digitally programmable current conveyor. International Journal of Circuit Theory and Applications. doi: 10.1002/cta.786.
- 27.Jerabek, J., & Vrba, K. (2009). Design of SIMO-type universal filter with adjustable parameters. In 32nd International conference on telecommunications and signal processing (TSP 2009) (pp. 38–42).Google Scholar
- 31.MOSIS parametric test results of TSMC LO_EPI SCN018 technology. Retrieved 24 May 2012 from ftp://ftp.isi.edu/pub/mosis/vendors/tsmc-018/t44e_lo_epi-params.txt.