A level-crossing flash asynchronous analog-to-digital converter

Distributed sensor networks, human body implants, and hand-held electronics have tight energy budgets that necessitate low power circuits. Most of these devices include an analog-to-digital converter (ADC) to process analog signals from the physical world. We describe a new topology for an asynchronous analog-to-digital converter, dubbed LCF-ADC, that has several major advantages over previously-designed ADCs, including reduced energy consumption and/or a simplification of the analog circuits required for its implementation. In this paper we describe the design of the LCF-ADC architecture, and present simulation results that show low power consumption. We discuss both theoretical considerations that determine the performance of our ADC as well as a proposed implementation. Comparisons with previously designed asynchronous analog-to-digital converters show the benefits of the LCF-ADC architecture. In 180 nm CMOS, our ADC is expected to consume 43 muW at 160 kHz, and 438 muW at 5 MHz

[1]  T. Kealey,et al.  More is less , 2000, Nature.

[2]  S. O. Rice,et al.  Statistical properties of a sine wave plus random noise , 1948, Bell Syst. Tech. J..

[3]  B. Kedem,et al.  Spectral analysis and discrimination by zero-crossings , 1986, Proceedings of the IEEE.

[4]  A. Willsky,et al.  Signals and Systems , 2004 .

[5]  Gilles Sicard,et al.  A 120nm low power asynchronous ADC , 2005, ISLPED '05. Proceedings of the 2005 International Symposium on Low Power Electronics and Design, 2005..

[6]  E. W. Williams,et al.  Integrated converters : D to A and D architectures, analysis and simulation , 2001 .

[7]  Alain J. Martin.  Programming in VLSI: from communicating processes to delay-insensitive circuits , 1991 .

[8]  Alain J. Martin.  The limitations to delay-insensitivity in asynchronous circuits , 1990 .

[9]  F. Beutler.  Error-Free Recovery of Signals from Irregularly Spaced Samples , 1966 .

[10]  Alain J. Martin.  Compiling communicating processes into delay-insensitive VLSI circuits , 2005, Distributed Computing.

[11]  Rajit Manohar,et al.  BitSNAP: dynamic significance compression for a low-energy sensor network asynchronous processor , 2005, 11th IEEE International Symposium on Asynchronous Circuits and Systems.

[12]  Jens Sauerbrey,et al.  A 0.5-V 1-μW successive approximation ADC , 2003, IEEE J. Solid State Circuits.

[13]  Alexandre Yakovlev,et al.  Synchronous and asynchronous A-D conversion , 2000, IEEE Trans. Very Large Scale Integr. Syst..

[14]  Kristofer S. J. Pister,et al.  An ultra–low power ADC for distributed sensor networks , 2002 .

[15]  Kenneth L. Shepard,et al.  Continuous-time digital signal processors , 2005, 11th IEEE International Symposium on Asynchronous Circuits and Systems.

[16]  Jon W. Mark,et al.  A Nonuniform Sampling Approach to Data Compression , 1981, IEEE Trans. Commun..

[17]  Paul Jespers.  Integrated D/A and A/D converters , 1988 .

[18]  Henrik V. Sorensen,et al.  A level-crossing sampling scheme for A/D conversion , 1996 .

[19]  C. A. R. Hoare,et al.  Communicating sequential processes , 1978, CACM.

[20]  Ed. McKenzie.  10. Time Series Analysis by Higher Order Crossings , 1996 .

[21]  A. Scaglione,et al.  Dense sensor networks that are also energy efficient: when 'more' is 'less' , 2005, MILCOM 2005 - 2005 IEEE Military Communications Conference.

[22]  Roubik Gregorian,et al.  Introduction to CMOS OP-AMPs and Comparators , 1999 .

[23]  Gilles Sicard,et al.  A new class of asynchronous A/D converters based on time quantization , 2003, Ninth International Symposium on Asynchronous Circuits and Systems, 2003. Proceedings..

[24]  Kenneth L. Shepard,et al.  A Continuous-Time Programmable Digital FIR Filter , 2005, IEEE Journal of Solid-State Circuits.

[25]  Low power, low noise micropipelined flash A-D converter , 1999 .

[26]  Yannis P. Tsividis.  Digital signal processing in continuous time: a possibility for avoiding aliasing and reducing quantization error , 2004, 2004 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[27]  Hiroshi Inose,et al.  Asynchronous delta-modulation system , 1966 .

[28]  B. Logan.  Information in the zero crossings of bandpass signals , 1977, The Bell System Technical Journal.

[29]  Enrico Mach,et al.  FOR LOW POWER , 1997 .