A Design of Variable-Cutoff-Frequency CMOS High-Pass Filter using Low-Bias Current Control

Xuan Thanh Pham

doi:10.21553/rev-jec.431

A Design of Variable-Cutoff-Frequency CMOS High-Pass Filter using Low-Bias Current Control

Xuan Thanh Pham

Abstract

This paper presents a variable-cutoff-frequency CMOS high-pass filter, which is designed for low-power analog front-end applications. The filter employs a weak-inversion MOSFET network to synthesize a GΩ-range equivalent resistance, enabling low-frequency operation without relying on large on-chip resistors. The cutoff frequency is adjusted by a low-bias current control scheme consisting of four selectable 300 pA branches, which tune the effective equivalent resistance while maintaining minimal power consumption. A comparator utilizes a folded cascode stage for common-mode stabilization and accurate bias control. Implemented in a 180 nm CMOS technology, the proposed prototype occupies 0.0045 mm2, consumes 0.749 µW, and provides five programmable high-pass corner frequencies ranging from 50 Hz to 100 kHz. The aforementioned features make the proposed architecture suitable for compact, energy-efficient front-end systems requiring reliable and tunable high-pass filtering.

References

Q. Lin, S. Song, I. D. Castro, H. Jiang, M. Konijnenburg, R. van Wegberg, D. Biswas, S. Stanzione, W. Sijbers, C. Van Hoof, F. Tavernier, and N. Van Helleputte, “Wearable multiple modality bio-signal recording and processing on chip: A review,” IEEE Sensors Journal, vol. 21, no. 2, pp. 1108–1123, 2021.

D. Csipkes, R. Groza, G. Csipkes, E. Stetco, A. Fodor, and O. A. Pop, “Low-power analog front end for ecg signal acquisition,” in 2025 IEEE 31st International Symposium for Design and Technology in Electronic Packaging (SIITME), 2025, pp. 245–248.

M. Jusko and P. Lukacs, “Design of analog front end for measuring bioimpedance,” in 2025 International Spring Seminar on Electronics Technology (ISSE), 2025, pp. 1–5.

B. Lee and M. Ghovanloo, “An overview of data telemetry in inductively powered implantable biomedical devices,” IEEE Communications Magazine, vol. 57, no. 2, pp. 74–80, 2019.

S. Gayathri, M. S. Pradeep, and N. S. S. L. V. Prasad, “Manas: Integrating advanced ai for personalized mental health support, crisis intervention, and medical insights,” in 2025 3rd International Conference on Intelligent Data Communication Technologies and Internet of Things (IDCIoT), 2025, pp. 2253–2262.

H. Yin, X. Mu, H. Li, X. Liu, and A. J. Mason, “Cmos monolithic electrochemical gas sensor microsystem using room temperature ionic liquid,” IEEE Sensors Journal, vol. 18, no. 19, pp. 7899–7906, 2018.

M. Cai, H. Sun, T. Yang, H. Hu, X. Li, and Y. Jia, “Continuous monitoring with ai-enhanced biomems sensors: A focus on sustainable energy harvesting and predictive analytics,” Micromachines, vol. 16, no. 8, 2025.

R. F. Yazicioglu, S. Kim, T. Torfs, H. Kim, and C. Van Hoof, “A 30 µ w analog signal processor asic for portable biopotential signal monitoring,” IEEE Journal of Solid-State Circuits, vol. 46, no. 1, pp. 209–223, 2011.

T. Zeng, Y. Wu, and M. Lei, “Review: Developments and challenges of advanced flexible electronic materials for medical monitoring applications,” Advanced Composites and Hybrid Materials, vol. 7, no. 5, p. 141, Sep. 2024.

H.-Q. Chen and Z.-C. Hao, “Varactor-based tunable high-pass filter with symmetrically cascaded quasielliptic sub-filters,” in 2025 IEEE MTT-S International Wireless Symposium (IWS), 2025, pp. 1–3.

D. Y. C. Lie, V. Das, W. Hu, Y. Liu, and T. Nguyen, “A low-power cmos analog front-end ic with adjustable on-chip filters for biosensors,” Open Journal of Applied Biosensor, vol. 02, no. 04, p. 104–111, 2013.

P. Horowitz and W. Hill, The art of electronics, third edition, 21st printing with corrections ed. Cambridge, New York: Cambridge University Press, 2024.

B. Razavi, Design of analog CMOS integrated circuits, second edition ed. New York, NY: McGraw-Hill Education, 2017.

J. A. De Lima and W. A. Pimenta, “A fully integrated high-pass filter for very low frequency applications,” in 2009 IEEE International Symposium on Circuits and Systems, 2009, pp. 257–260.

C. C. Enz, F. Krummenacher, and E. A. Vittoz, “An analytical mos transistor model valid in all regions of operation and dedicated to low-voltage and low-current applications,” Analog Integrated Circuits and Signal Processing, vol. 8, no. 1, p. 83–114, Jul. 1995.

M. Choi, B. Kim, S. Lee, K. Kim, M. Yoo, J. Wi, G. Nam, M. Son, I. Yoo, J. Bae, and H. Ko, “Implantable cardiovascular biopotential acquisition and stimulation circuit with body-channel communication for transcatheter leadless pacemaker,” IEEE Transactions on Biomedical Circuits and Systems, vol. 19, no. 5, pp. 920–935, 2025.

DOI: http://dx.doi.org/10.21553/rev-jec.431

Copyright (c) 2026 REV Journal on Electronics and Communications

ISSN: 1859-378X

Username
Password
Remember me