Smart Sensor Systems 2008

!!! Extended registration date: April 13, 2008!!!
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Contents of the course

2. Where and How to Apply Smart Sensor Systems
Johan H. Huijsing, TU Delft
This lecture explains the need for non-expensive smart sensor systems for application in industrial production machines and consumer appliances.
Smart sensor systems will lead to a third automation revolution. After the mechanization and information, “sensoration” will lead to full self-operating production means and consumer appliances. One will be able to tell his car to bring him to work in the morning and the car will do so, while the one being transported can read the newspaper in paper or on Internet.

3. Measurement techniques for smart sensor systems
Gerard C.M. Meijer, TU Delft
The architecture and design of low-cost high-performance sensor systems is reviewed. The sensor systems consist of a number of multiplexed sensor elements, sensor-specific front-ends modifiers and microcontrollers or DSPs. Important design targets are: a high accuracy, a high dynamic range, a high speed, low power consumption, an excellent reliability and low costs. It is shown that A/D conversion can be implemented in the microcontroller or DSP.

4. Silicon sensors: an introduction
Paddy J. French, TU Delft
In general, a sensor as a device forms the interface between the physical and chemical world to the electrical domain. The five measurand domains are: thermal, magnetic, mechanical, radiant, chemical. Silicon technology has made considerable advances in recent years and this is leading to increasing possibilities for silicon sensors. Silicon does not always make the best sensing element, but the possibility of integrating with electronics in a single device presents many advantages over the traditional approach. This lecture will give a general introduction to sensors and sensor principles leading to the sensor possibilities using silicon technology. technology.

5. Physical chemosensors
Michael J. Vellekoop, Vienna University of Technology, Austria
The measurement of fluid properties, for example in medicine or in the production of chemicals, is of high societal and economic relevance. The research efforts in the field of fluid (chemo)sensors are significant. Some of the typical problems of chemosensors are the fabrication of a reproducible and stable chemical-active interface, and reducing the effects of aging, clogging and contamination of the interface. By applying measurement methods based on physical effects instead of on chemical effects, the above-mentioned problems can be circumvented. The miniaturization of analysis systems by silicon integration yields other advantages such as high-speed handling and low costs, and the possibility of adding integrated electronics. Examples of integrated systems that will be discussed are nanoliter arrays for high-speed screening (HSS), gas chromatograph thermal detectors, a multiparameter sensor system for oil condition monitoring, liquid conductivity detection in ion separators, and optical particle detectors. Also, developments in particle separation and sorting based on dielectrophoresis will be discussed. The usability of such systems for cell analysis is currently a topic with high interest. Direct and SU-8 Wafer-bonding technology will be described as an example of specific technology developments for the fabrication of fluidic devices including microsensors and –actuators.

6. Introduction to CMOS-based DNA Microarrays
Roland Thewes, Infineon, Munich, Germany
Fully electronic DNA sensors and CMOS-based DNA sensor arrays have gained huge interest in recent years since they provide advantages compared to state-of-the-art commercially available tools for the same purpose using optical principles.
In this lecture, an overview is given starting with the general operation principle of DNA microarrays, optical and electronic functionalization techniques, optical and electronic detection principles, labeling-based and label-free read-out. Then, CMOS integration issues and the related processing requirements are briefly discussed.
Special emphasis is put on the related CMOS circuit design requirements in terms of sensitivity, stability, and further parameters depending on the particular application. Examples from the literature are considered to demonstrate opportunities and limitations of CMOS chips applied in that field.

7. Integrated Hall magnetic sensors
Pavel Kejik, EPFL, Lausanne, Switzerland
The lecture starts with a brief introduction into the Hall effect and Hall elements. Then the problems and good practices in the realization of integrated Hall magnetic sensors will be reviewed. The main issues are offset, temperature cross-sensitivity, switching noise, and drift related to the packaging stress. By combining Hall elements with well-adapted interface electronics some of the problems can be dramatically reduced. It will be shown that integration of magnetic flux concentrators on the sensor chip will further decrease the equivalent magnetic noise and offset.

8. Capacitive Sensors
Xiujun Li, TU Delft
A systematic approach towards the design of reliable smart low-cost high-performance capacitive sensors is presented. The basis problems and their solutions of both the physical and the electrical signal processing are discussed. The examples concern capacitive sensors in position detectors, liquid-level detectors and personnel detectors.

9. Smart temperature sensors
Gerard C.M.Meijer, TU Delft
An overview of existing temperature sensors will be given. Specific advantages and disadvantages will be discussed. Special attention will be given to the architecture and performance of integrated temperature sensors. As a result of the ongoing computerization and reduction of IC-costs these sensors have a rapidly growing market. Some case studies of integrated sensors in practical applications will be presented.

10. Optical Sensors Based on Photon Detection
Reinoud F. Wolffenbuttel, TU Delft
Optical photon detectors fabricated in CMOS can be designed for operation in the UV, visible and near-IR spectral range. Their opto-electrical performance and co-integration with readout circuits has promoted use in a wide range of applications. This presentation discusses the limitations and merits of CMOS-compatible photon detectors. The emphasis is on the main design conside¬rations, such as detection limit and spectral operating range, and their dependence on transmission through the surface passivation layer, doping profile and detector internal gain. Moreover, the operating mechanisms of devices such as the photoconductor, the photodiode and the avalanche photon detector are outlined. Finally, application examples such as a bi-chromatic color sensor for object identification and MEMS-based micro spectrometers are presented.

11. Visit to Dimes Technology Center
Cassan Visser, TU Delft

12. Discussions and demonstrations
Dafina Tanase & Maureen Meekel, TU Delft

13. Interface electronics and busses
Frank Riedijk, Xensor Integration, Delfgauw
The lecture will review the most important developments in smart-sensor interface technology and the applied transmission methods. Especially A/D conversion technology, such as duty-cycle and sigma-delta conversion and communication trends on sensor-component level will be highlighted. Examples of the applied techniques in today’s products will be presented.

14. Smart pressure transducer interface for high-temperature application
Paul C. de Jong, ECN, Petten
It is shown, how to design a transducer interface for high-temperature applications. Application of the discussed design techniques could also be of benefit to improve the reliability of "normal" electronics. Special circuit techniques developed to reduce maintenance effort and to improve long-term stability are presented. The design of an opamp able to withstand temperatures up to 300º C is discussed. Finally, a pressure-transducer interfacing ASIC, that does not require any calibration, will be presented.

15. Universal asynchronous sensor interfaces
Gerard C.M. Meijer, TU Delft
In this lecture it is shown that relaxation oscillators are very suited to be applied as modifiers for many types of sensor signals at their input. The modulated output signals can directly be read out by microcontrollers and DSPs.
To connect different types of sensing elements at the modulator input different types of sensor-specific front-ends are required. The features of the overall systems are discussed for capacitive and resistive (bridge) transducers.

16. Introduction to CMOS Image Sensor
Albert Theuwissen, Harvest Imaging, Bree, Belgium
Today, solid-state image sensor can be found everywhere : from mobile phones to broadcast cameras, from optical mise to medical cameras. Most of the high-end cameras are based on CCD sensors, but imagers made in standard CMOS technologies got their place already in the low-end markets. CMOS imagers are characterized by a higher on-chip functionality, low power, random accessability and in many case a low price. CCDs are still superior in image quality, but CMOS imagers are improving as well !
This short presentation will give an overview of the CMOS imager applications and the technologies in which these devices are being fabricated.

17/22. Hands-on Demonstrations Part 1 and Part 2
Zu-Yao Chang
, Ger de Graaf, Ali Heidary, Xiujun Li, Guijie Wang
, TU Delft
About 15 demonstrations (µC + PC based) will be available in the hands-on midday. Assisted by instructors, the participants will play with each demonstration. Questions can be raised and discussed during the hands-on activity.
The demonstrations include: Smart temperature measurement systems, temperature control systems, ethernet sensor systems, smart sensor systems applying universal transducer interfaces for rapid prototyping, a capacitive humidity measurement system, a capacitive liquid-level detector, a resistive pressure measurement system, multiple-sensor systems, magnetic angular encoders.

18. Digital tuning reduces gyroscope drift and power
Bernhard E. Boser, University of Berkeley, USA
Matching sense and drive resonances in gyroscopes significantly increases sensitivity at the expense of increased sensitivity to fabrication tolerances and environmental effects. This work overcomes these problems with digital tuning loops that continually monitor and electrostatically tune the sense resonance. A digital feedback loop eliminates the susceptibility of the gyroscope transfer function to Q-factor variations and enables the use of low power open-loop sensing. The measured spot noise is 14deg/h/rt-Hz at 1mW power dissipation, representing more than an order-of-magnitude improvement over the state-of-the-art.

19. Calibration and Self-Calibration of Smart Sensors
Michiel A.P. Pertijs, National Semiconductor, Delft
This lecture introduces the concepts of calibration, trimming, and self-calibration in the context of smart sensors. The role of calibration in defining the accuracy of a smart sensor will be discussed. The trade-off between guaranteeing accuracy by calibration and by design will be illustrated using a smart temperature sensor. Various interpretations of the term ‘self-calibration’ will be discussed. The concept of a self-calibrating sensactor (a combination of a sensor and actuator) will be illustrated using a smart wind sensor and a Hall sensor.

20. Dynamic offset-cancellation techniques
Kofi A. A. Makinwa, TU Delft
An introduction to dynamic-offset-cancellation techniques will be given. It will be shown that, in combination with smart sensor interfaces, new topologies can be developed which have less offset and noise than existing solutions. A smart spinning-current Hall plate interface will be shown which has sub-µV input offset. Also shown, will be a precision comparator for use in a thermal sigma-delta modulator with less than 10 µV offset.

21. Automotive sensors
T. Tiek, Sensata, Almelo
The lecture gives an overview of design considerations for Application Specific Integrated Circuit development for automotive sensors. Today’s automotive sensor ASICs need to provide increased functionality and accuracy under extreme conditions (e.g. temperature, EMC…) at a very low cost.
Automotive ASIC development will first be explained in general, followed by a specific example of a mixed mode pressure sensor ASIC that is actually being produced in high volume for modern passenger cars.