With the new habits of lifestyle, new health problems are arising and demands continuous
health monitoring. Wearable technology will revolutionize our lives in the upcoming years.
To enable widespread usage of such devices, it is important to maximize their functionality
while minimizing manual intervention, with extended life time, flexibility and at low-cost. The
advancement of miniature and flexible devices has fostered a dramatic growth of interest in
this technology. Currently, most of the wearable biomedical systems are c-Si based, which are
typically rigid, bulky (due to battery size), expensive in terms of fabrication cost and requires
some external interface. They limit mobility and comfort of the wearer. Typically in hospitals,
in order to monitor ECG signals, which is a part of routine for the cardiovascular patients, is
done through ECG measurement equipment with many electrodes and long wires, which limits
the patient's mobility. In the same way, BP measurement using cuffs is very inconvenient when
frequent measurements need to be recorded. Both these approaches need human interaction.
Though some commercial wearable devices are available for biomedical monitoring, which
are confined to few biological signal monitoring that includes ECG, EEG, temperature sensor
or for the measurement of pulse rate. Compact, reliable and light weight systems, that can
monitor the variety of biological signals is still an open challenge. Researchers have been
actively seeking for innovative solutions and new technologies that could improve the quality
of patient care meanwhile reduce the cost through early detection of serious health problems.
In order to address these issues, this work targets to build a self-contained noninvasive
flexible real-time health monitoring front-end, which is compact and do not limit the wearer's
mobility. The proposed system can be successfully used by many people ranging from infants,
sportsman, elderly people and post-hospitalized patients, where, continuous health monitoring
is vital. Further the idea can be extended to store the biological signals over a time period so
that doctor can have complete record of the patient's health condition.
In order to bring the proposed biomedical wearable front-end into a reality, many signal
conditioning and processing circuits need to be developed with oxide TFT technology (a-IGZO),
as it can facilitate fabrication of circuits on flexible substrates. The circuits that are included are
on-chip power supply (bootstrapping circuit), clock generators (ring oscillators), pre-amplifier
to amplify biomedical signals for pre-processing, low-pass filters (anti-aliasing filter) and ADC
(Analog-to-Digital Converter). The biological signals (output of the bio-sensors) need to be
processed through these analog and mixed signal blocks in order to transmit the data to the
server/smart phone so that in case of an emergency, an alert can be sent to the doctor/wearer in
order to provide immediate medical assistance. This type of remote monitoring of the important
biological signals in real-time data can significantly minimize health risks.
