A general domain CMOS companding integrator

ABSTRACT

This work presents a new architecture of companding integrator for application in CMOS current-mode filters. Since MOS transistors can operate in the whole inversion region, this circuit can be classified either as log-domain or as square-root domain. Due to the higher bias currents allowed, signal-to-noise(distortion) ratio is improved in comparison to the log-domain counterparts. Circuit complexity is intermediate between log-domain and square-root domain companding integrators.

REFERENCES

• 1: Tsividis, Y. Externally linear, time-invariant systems and their application to companding signal processors. IEEE Trans. Circuits and Systems - II: Analog and Digital Signal Processing, 44, (Feb. 1997), 65--85.
• 2: Seevinck, E. Companding current-mode integrator: a new circuit principle for continuous-time monolithic filters. Electronics Letters, .26, (Nov. 1990), 2046--2047.
• 3: Seevinck, E., Vittoz, E., du Plessis, M., Joubert, T.-H. and Beetge, W. CMOS translinear circuits for minimum supply voltage. IEEE Trans. Circuits and Systems - II: Analog and Digital Signal Processing, 47, (Dec. 2000), 1560--1564.
• 4: Zhang, X., Mekawi, W. and El-Masry, E. Leap-frog-based synthesis of CMOS micropower nth-order log-domain filters. In Proceedings of the 2nd Annual Northeast Workshop on Circuit and Systems (June, 2004), 305--308.
• 5: Fried, R. and Enz, C. A family of very low-power analog building blocks based on CMOS translinear loops. In Proceedings of the 2nd IEEE CAS Region 8 Workshop on Analog and Mixed IC Design (September, 1997), 73--78.
• 6: Redondo, X. and Serra-Graells, F. Exact design of all-MOS log filters. In Proceedings of the IEEE International Symposium on Circuits and Systems (Vancouver, May, 2004), 25--28.
• 7: J. Veerendra Kumar , K. Radhakrishna Rao, A Low-Voltage Low Power CMOS Companding Filter, Proceedings of the 16th International Conference on VLSI Design, p.309, January 04-08, 2003
• 8: Maniero,A., Gerosa, A. and Neviani, A. Performance optimization in micro-power, low-voltage log-domain filters in pure CMOS technology. In Proceedings of the IEEE International Symposium on Circuits and Systems, vol.I (Bangkok, May, 2003), 565--568.
• 9: Maniero, A., Gerosa, A. and Neviani, A. A fully integrated dual-channel log-domain programmable preamplifier and filter for an implantable cardiac pacemaker. IEEE Trans. Circuits and Systems - I: Regular Papers, 51, (Oct. 2004), 1916--1925.

INDEX TERMS

Primary Classification:
  B. Hardware
  B.7 INTEGRATED CIRCUITS
      B.7.0 General

General Terms:
Design, Performance, Theory

Keywords:
CMOS integrators, companding circuits, log-domain integrators, square-root domain integrators