|
Title:
|
An intelligent ISFET sensory system with temperature and drift compensation for long-term monitoring.
|
|
Author:
|
Chen, D. Y.; Chan, Pak Kwong.
|
|
Copyright year:
|
2008 |
|
Abstract:
|
This paper presents a new intelligent ISFET sensory
system dedicated to a precision pH sensory function, as well as
a long-term monitoring capability without being jeopardized by
temperature and drift fluctuations in the water-quality monitoring
environment. It includes the novel compensation technique for
counteracting a simultaneous change of temperature and drift,
the design of the sensory system incorporating hardware and
software co-design for enhancing the performance stability of a
standard ISFET device and a new programmable current source
with reduced dynamic current error for a dedicated temperature
compensation process. The proposed ISFET sensory system, with
about a 0.01 pH resolution in system design at a 3.3 V supply,
has been validated by the experiments, exhibiting a maximum
accuracy error of 0.02 pH at 23°C and 0.05 pH at 40°C with dual
compensation. The compensation results show a maximum time
drift of 0.003 pH/°hour (0.166 mV/°hour) at 23°C and an average
temperature drift of 0.00049 pH hour°C (0.0245 mV hour°C)
for a reference temperature increase from 23°C to 40°C, with
the value of the pH solution ranging from 4 to 9 in six-hour
measurements. These measured results outperform those of the
reported drift reduction techniques, suggesting that the ISFET
sensory system using novel compensation can provide significant
immunity against temperature change, time drift, and temperature
drift, which are favorable towards robust measurements in
environmental monitoring applications. |
|
Subject:
|
DRNTU::Engineering::Electrical and electronic engineering. |
|
Type:
|
Journal Article |
|
Series/ Journal Title:
|
IEEE sensor journal |
|
School:
|
School of Electrical and Electronic Engineering |
|
Rights:
|
© 2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder. http://www.ieee.org/portal/site This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder. |
|
Version:
|
Published version |
