Prof. Yannis Tsividis
Columbia Integrated Systems Lab
Many new and emerging applications require extremely low power dissipation in order to preserve scarce energy resources; such applications include sensor networks and wearable/implantable/ingestible biomedical devices. In such cases, uniform sampling, as used in conventional, clocked circuits, represents undesirable and unnecessary energy waste. We review techniques in which the signal itself dictates when it needs to be sampled and processed, thus causing energy use only when demanded by the information in it. Methods for implementing event-driven A/D converters and DSPs in this context, without using any clock, are reviewed. It is shown that, compared to traditional, clocked techniques, the techniques reviewed here produce circuits that completely avoid aliasing, respond immediately to input changes, result in better error spectral properties, and exhibit dynamic power dissipation that goes down when the input activity decreases. Recent test chips, operating at kHz to GHz signal frequencies, fully confirm these properties.
Yannis P. Tsividis is Bachelor Professor of Electrical Engineering at Columbia University in New York. Starting with the first fully integrated MOS operational amplifier, which he demonstrated in 1976, he has worked in analog and mixed-signal integrated circuits at the device, circuit, system, and computer simulation level. He received the 1984 IEEE W.R.G. Baker Award for the best IEEE publication, and is recipient or co-recipient of best paper awards from the IEEE International Solid-State Circuits Conference in 2003 and the IEEE Circuits and Systems Society (Darlington Award, 1987; Guillemin-Cauer Award, 1998 and 2008). He has received Columbia’s Presidential Award for Outstanding Teaching in 2003, the IEEE Undergraduate Teaching Award in 2005, and the IEEE Circuits and Systems Society Education Award in 2010. He is a Fellow of the IEEE, and received the IEEE Gustav Robert Kirchhoff Award in 2007.