Copyright © 2007 The Institute of Electronics, Information and Communication Engineers
Regular Section -- Papers -- Electronic Circuits |
An Ultra-Low Power Variable-Resolution Sigma-Delta Modulator for Signals Acquisition of Biomedical Instrument
1 The authors are with the Wireless Mixed Biochip Laboratory, EE, NCKU, Tainan 70146, Taiwan. E-mail: robinluo{at}mail.ncku.edu.tw
In this paper, an ultra-low power variable-resolution sigma-delta (
) modulator for biomedical application is presented. The resolution of proposed modulator can be adjusted by switching its sampling frequency and architecture. The architecture is switched between second-order single-loop modulator and fourth-order cascaded second stage noise shaped modulator to reach different resolution requirement. The proposed sigma-delta modulator is implemented by single phase integrators based on a fully differential switched-capacitor circuit. The digital cancellation logic is embedded in the chip so that it would easily be integrated with biomedical instrument for effective acquisition. Experimental results of the proposed variable-resolution modulator fabricated in standard CMOS 0.18µm technology confirm the expected specifications from 65 dB signal-to-noise distortion to 96 dB with 1 kHz bandwidth and power consumption range from 48µW to 360µW with a 1.8 V battery supply.
Key Words: sigma-delta modulator, variable-resolution, ultra low power, biomedical
Manuscript received November 30, 2006. Manuscript revised March 14, 2007.
References
[1] E.N. Bruce, Biomedical Signal Processing and Signal Modeling, John Wiley & Sons, New York, 2001. [2] G. Bondini, A.S. Brogna, C. Garbossa, L. Colombibi, M. Bacci, S. Chicca, F. Bigongiari, N.C. Guerrini, and G. Ferri, "An ultralow-power switched opamp-based 10-B integrated ADC for implantable biomedical applications," IEEE Trans. Circuits Syst., vol.51, no.1, pp.174–178, Jan. 2004. [3] J. and G. Webster, eds., Medical Instrumentation — Application and Design, pp.258–259, Wiley, New York, 1998. [4] J. Goes, N. Paulino, H. Pinto, R. Monteiro, B. Vaz, and A.S. Garcao, "Low-power low-voltage CMOS A/D sigma-delta modulator for bio-potential signals driven by a single-phase scheme," IEEE Trans. Circuits Syst., vol.52, no.12, pp.2595–2604, Dec. 2005. [5] A. Gerosa, A. Maniero, and A. Neviani, "A fully integrated two-channel A/D interface for the acquisition of cardiac signals in implantable pacemakers," IEEE J. Solid-State Circuits, vol.39, no.7, pp.1083–1093, July 2004. [6] Z. Lu, Y. Hu, and M. Sawan, "A 900 mV 66µW sigma-delta modulator dedicated to implantable sensors," IEICE Trans. Inf.& Syst., vol.E88-D, no.7, pp.1610–1617, July 2005. [7] E. Kyriacou, S. Pavlopoulos, A. Berler, M. Neophytou, A. Bourka, A. Georgoulas, A. Anagnostaki, D. Karayiannis, C. Schizas, C. Pattichis, A. Andreou, and D. Koutsouris, "Multi-purpose HealthCare Telemedicine Systems with mobile communication link support," BioMedical Engineering OnLine 2003, 2:7. [8] V. Peluso, M. Steyaert, and W. Sansen, Design of Low-Voltage Low-Power CMOS Delta-Sigma A/D Converters, Kluwer Academic Publishers, Boston, MA, 1999. [9] J. Crols and M. Steyaert, "Switched-opamp: An approach to realize full CMOS switched-capacitor filters at very low power supply," IEEE J. Solid-State Circuits, vol.29, no.8, pp.936–942, Dec. 1997. [10] S.R. Norsworthy, R. Schreier, and G.C. Temes, Delta-Sigma Data Converters Theory, Design, and Simulation, IEEE Press, New York, 1997. [11] A. Marques, V. Peluso, M.S. Steyaert, and W.M. Sansen, "Optimal parameters for [12] A. Marques, V. Peluso, M. Steyaert, and W. Sansen, "Optimal peramters for cascade [13] C. Renato T. de Mori, P.C. Crepaldi, and T.C. Pimenta, "A 3-V12-bit second order sigma-delta modulator design in 0.8-µm CMOS," Grupo de Microelectronica-Escola federal de Engenharia de Itajuba, pp.124–129, 2001. [14] T. Kajita, G.C. Temes, and U.-K. Moon, "Correlated double sampling integrator insensitive to parasitic capacitance," Electron. Lett., vol.37, no.3, pp.151–153, Feb. 2001. [15] P. Malcovati, S. Brigati, F. Francesconi, F. Maloberti, P. Cusinato, and A. Baschirotto, "Behavioral modeling of switched-capacitor sigma-delta modulators," IEEE Trans. Circuits Syst., vol.50, no.3, pp.352–364, Sept. 1998. [16] A. Yukawa, "A CMOS 8-bit high-speed A/D converter," IEEE J. Solid-State Circuits, vol.SC-20, no.3, pp.775–779, June 1985.
modulator topologies," IEEE Trans. Circuits Syst., vol.45, no.9, pp.1232–1241, Sept. 1998. modulator," Proc. ISCAS'97, pp.61–64, 1997.
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