The Realization of Current-Mode Electronically Tunable Square-Root Domain Low-pass Filter Based on CMOS Technology for Biomedical Applications

Abstract

In this study, a second-order low-pass filter with low-power and voltage, current mode and square-root domain was designed for biomedical implementations at low frequencies using the state-space-synthesis method. The filter, which is activated at 3V supply voltage, is formed using current mirrors, current-mode square-root circuits, and grounded capacitors. To indicate the performance of the filter, some simulations are carried out using process parameters of TSMC 0.25µm CMOS in the program of ORCAD Capture CIS. The results of these simulations show that the center frequency of low-pass filter can be tuned electronically between the range of 1 kHz and 120 kHz and that there appears to be a 0.5% total harmonic distortion. The proposed circuit has some advantages, such as activating at low-frequency operation, low power supply, tunability, and low total harmonic distortion.

Keywords

• Biomedical
• Companding
• Current-mode
• Low-frequency
• Low-pass
• Square-root-domain

Project Number

19087

References

1. [1]. R. W. Adams, “Filtering in Log Domain”, 63 rd AES Conf., s.1470, 1979.
2. [2]. E. Seevinck, “Companding current-mode integrator: A new circuit principle for continuous-time monolithic filters,” Electronics Letters, vol. 26, no. 24, p. 2046, 1990.
3. [3]. D. R. Frey, “Log-domain filtering: an approach to current-mode filtering”, IEE Proceedings G Circuits, Devices and Systems, 140(6), p.406., 1993.
4. [4]. C. Toumazou, J. Ngarmnil, and T. S. Lande, “Micropower log-domain filter for electronic cochlea,” Electronics Letters, vol. 30, no. 22, pp. 1839–1841, 1994.
5. [5]. M. H. Eskiyerli, A. J. Payne, and C. Toumazou, “State space synthesis of integrators based on the MOSFET square law,” Electronics Letters, vol. 32, no. 6, p. 505, 1996.
6. [6]. M. H. Eskiyerli and A. J. Payne., “Square Root Domain filter design and performance”, Analog Integrated Circuits Signal Process, 22, pp. 231–243, 2000.
7. [7]. Lopez-Martin, A. J., and Carlosena, A., “Systematic design of companding systems by component substitution”, Analog Integrated Circuits Signal Process, 28, pp. 91–106, 2001.
8. [8]. Yu, G.J., Liu, B.D., Hsu, Y.C., and Huang, C.Y., “Design of Square-Root Domain Filters”, Analog Integrated Circuits and Signal Processing, 43, 49–59, 2005.

9. [9]. Menekay, S., Tarcan, R.C., and Kuntman, H., “The Second-order low-pass filter design with a novel higher precision square-root circuit”, Istanbul Univ., J. Electr. Electron., 7, 1, 323–729, 2007.
10. [10]. Eskiyerli, M. H., Payne,A.J., and Toumazou, C., “State-Space Synthesis of Biquads Based on The MOSFET Square Law”, Circuits and Systems, 1996. ISCAS '96, vol. 1.pp. 321–324, Atlanta, GA, USA, 12–15 May 1996.
11. [11]. Keserlioglu, M. S., and Kircay, A., “The design of current-mode electronically tunable first-order square-root domain filters using state-space synthesis method”, International Review on Modelling and Simulations, Vol.2, N.2, pp.124-128, April 2009.
12. [12]. Mulder, J., “Static and dynamic translinear circuits”, Delft University Press, Netherlands, 1998.
13. [13]. Lopez-Martin,A. J., and Carlosena, A., “Very low voltage CMOS companding filters based on the MOS translinear principle”, Mixed-Signal-Design, 2001, SSMSD, Southwest Symposium on, pp. 105-109.
14. [14]. Menekay, S., Tarcan, R. C., and Kuntman, H., “Novel high-precision current-mode-circuits based on the MOS-translinear principle” IntJElectronCommun(AEU) DOI:10.1016/j.aeue.2008.08.010, 2008.
15. [15]. Lopez-Martin, A. J., and Carlosena, A., “1.5 V CMOS companding filter”, Electronics Letters, Vol.: 38, Issue: 22, pp.: 1346-1348, 2002.
16. [16]. A. Kircay, M. S. Keserlioglu, and F. Z. Adalar, “Electronically tunable current-mode third-order square-root-domain filter design,” Journal of Circuits, Systems and Computers, vol. 27, no. 09, p. 1850136, 2018.
17. [17]. Kircay, A., and Keserlioglu, M. S., “Novel Current-Mode Second-Order Square-Root-Domain Highpass and Allpass Filter”, 6th Int. Conf. on Elecrical and Electronics Engineering, 5-8 November 2009, Bursa, Türkiye
18. [18]. A. Kircay, M. S. Keserlioglu, and F. Z. Sagi, “Design of third-order square-root-domain filters using state-space synthesis method,” 2015 9th International Conference on Electrical and Electronics Engineering (ELECO), 2015.
19. [19]. Kircay, A., Keserlioglu, M. S., and Cam, U., “Current-Mode Square-Root-Domain Notch Filter” Europen Conference on Circuit Theory and Design 2009 Antalya, August 23–27, 2009
20. [20]. D. Thakur, K. Sharma and R. Sharma, "Ultra Low-Power Low-Pass Filter Design for Wearable Biomedical Applications," 2021 Devices for Integrated Circuit (DevIC), Kalyani, India, 2021, pp. 629-632, doi: 10.1109/DevIC50843.2021.9455815.
21. [21]. R. Bagavathiyammal and T. Muruganantham, "A Design of Cmos based 4th Order Low Pass Biquad Filter for Biomedical Applications," 2020 Second International Conference on Inventive Research in Computing Applications (ICIRCA), Coimbatore, India, 2020, pp. 1152-1155, doi: 10.1109/ICIRCA48905.2020.9182851.
22. [22]. G. K. Soni, H. Singh, H. Arora and A. Soni, "Ultra Low Power CMOS Low Pass Filter for Biomedical ECG/EEG Application," 2020 Fourth International Conference on Inventive Systems and Control (ICISC), Coimbatore, India, 2020, pp. 558-561, doi: 10.1109/ICISC47916.2020.9171138.
23. [23]. M. B. Elamien and S. A. Mahmoud, “An 114Hz–12MHz digitally controlled low‐pass filter for biomedical and wireless applications,” IET Circuits, Devices & Systems, vol. 12, no. 5, pp. 606–614, 2018.
24. [24]. J. R. Machha Krishna and T. Laxminidhi, “Widely tunable low‐pass Gm−c filter for biomedical applications,” IET Circuits, Devices & Systems, vol. 13, no. 2, pp. 239–244, 2019.
25. [25]. E. Alaybeyoglu and H. Kuntman, “Reconfigurable low-pass filter for analog baseband of Bluetooth Low Energy and biomedical applications,” Electrica, vol. 21, no. 1, pp. 142–150, 2021.
26. [26]. Yu, G-J, Tsao Y-J, and Lin, Y-S., “1V Square-Root Domain Low-pass Filter using Translinear Loop Technology in Biomedical Engineering”, Life Science Journal, vol 6, no 4, p. 92-96, 2009.
27. [27]. Yu, G-J, and Lin, Y-S., “Low Voltage Tunable Square-Root Domain Band-Pass Filter with Translinear Loop Technique in Biomedical Engineering”, Life Science Journal, vol 7, no 1, p. 30-33, 2010.
28. [28]. F. Z. Sagi, “Karekök ortamda akım modlu devre tasarımı” M.S. thesis, Harran Univ.,2015. Availible: https://tez.yok.gov.tr/UlusalTezMerkezi/TezGoster?key=WY5CM7tPNE2z_YM6pBu0tyt4OTxj8HNwskyrMaxF3CfBegacFrvyrYhxsZyeGWSY
29. [29]. C. Sakul, “A CMOS Square-Rooting Circuits.” The 23rd International Technical Conference on Circuits and System, Computer and Communications (ITC-CSCC 2008), 537-540, 2008.
30. [30]. Wıegerınk, R. J., 1993. Analysis and Synthesis of MOS Translinear Circuits (1st ed.). Kluwer Academic Publishers Norwell, USA.