SHF: Medium: Power-Adaptive, Event-Driven Data Conversion and Signal Processing Using Asynchronous Digital Techniques

Columbia University, New York NY

Investigators

Abstract

This research addresses an increasing demand and need for very low power and high-quality microelectronic systems that can continuously acquire and process information, as soon as it becomes available. Such data acquisition and real-time signal processing are used in a wide range of applications, such as environmental sensor networks (powered by solar cells or by energy harvesting using vibrational energy), and implantable or ingestible biomedical devices for prosthetics or for continuous diagnostics and monitoring. In these applications, new information is often generated infrequently, at irregular and unpredictable intervals. This event-based nature calls for a drastic re-thinking of how these signals are monitored and processed. Conventional synchronous (i.e. clocked) digital techniques, which use fixed-rate operation to evaluate data whether or not it has changed, are a poor match, often leading to high power consumption. This research aims instead to provide viable "event-based" systems: controlled not by a clock but rather by the arrival of each event. Such continuous-time data acquisition promises significant power and energy reduction, flexible support for a variety of signal processing protocols and encodings, high-quality output signals, and graceful scalability to future microelectronic technologies. Asynchronous (i.e. clockless) digital logic techniques, which are ideally suited for this work, are combined with continuous-time digital signal processing, to make this task possible; both of these areas have been researched by the principal investigators under prior NSF support. A series of silicon chips will be designed and fully evaluated, culminating in a fully programmable, event-driven data acquisition and signal processing system, which can be used as a testbed for a wide variety of real-world applications. This work is expected to have broad impact. The resulting chips and methodology will provide significant practical benefits in widely-used applications where energy resources are scarce, such as in biomedical electronics, sensor networks and portable communications devices, which must operate on a small battery for a long lifetime. The chip development will be directed towards these applications through close consultation with expert colleagues in biomedical engineering, and through the investigators? existing close ties with US microelectronics companies. In addition, the research is expected to provide fundamental new advances in ultra-low-power microelectronics systems, which can have an impact on such diverse areas as power electronics and new types of control systems for mechanical vibration control. Finally, the results of this work will be extensively disseminated to the research community, to promote and advance the practical use of these techniques, as well as to promote further research and education in this area, including through its incorporation into curricula at Columbia University and other leading universities.