Robert Rieger
Scientific Tracks Abstracts: J Inform Tech Soft Engg
Advances in CMOS technology, communication, and low power circuit design have spurred the development of wearable
bio-monitoring devices, leading to miniaturized and highly integrated systems for continuous streaming of physiological
multi-source data including force patterns, electrocardiogram (ECG), electromyogram (EMG) or impedance tomogram to
name just a few. We propose a body-wearable sensor device with a low-power transmission back-end incorporating a customdesigned
integrated circuit (ASIC) for the sensing front-end and for analog-to-digital conversion (ADC). A key aspect of
the design is its flexibility which allows it to be programmed in the field to operate with different types of input signal so
that a single hardware design can be used in a multimedia environment. The front-end configuration, single-ended, doubledifferential,
DC-coupled, AC-coupled, offset trimming etc., is selectable in software. A counter-ADC design is discussed as it
provides adjustable digital gain, variable input range, resolution and conversion speed. The data processing and transmission
rate (which determines power and media quality) is controlled depending on a metric derived dynamically by the receiver
using information on the media type, ambient data (e.g. battery charging level) and desired quality. Measured results from
a system prototype are presented. The ASICs were fabricated in TSMC 0.35μm technology. The programmable front-end
consumes between 110 and 324 μW depending on configuration, and the ADC core requires 36 μW for 8-bit conversion
at 8 kHz. Currently, a mid-range CPU (PIC18LF2520) and a wireless radio (MRF49XA) from Microchip, Inc. serve as the
controller and transmission unit respectively with the plan of future integration on chip.
Robert Rieger received the PhD degree in Electronic and Electrical Engineering from University College London (UCL), London, U.K., in 2004. He then joined
the Industry and Medical Business Unit of Austria microsystems AG, Rapperswil, Switzerland, as a Design Engineer involved in the design of robust low-power
integrated circuits. Since 2006 he is with the Department of Electrical Engineering, National Sun Yat-sen University, Taiwan. He is now a Professor of Electronics
Engineering and the Head of the Bionics Integrated Systems Laboratory. His research interests are in the areas of integrated electronics for biomedical application
and embedded and digitally assisted low-power analog circuits.
