Energy-Efficient Smart Temperature Sensors in CMOS Technology

This book describes the design and implementation of energy-efficient smart (digital output) temperature sensors in CMOS technology. To accomplish this, a new readout topology, namely the zoom-ADC, is presented. It combines a coarse SAR-ADC with a fine Sigma-Delta (SD) ADC. The digital result obtained from the coarse ADC is used to set the reference levels of the SD-ADC, thereby zooming its full-scale range into a small region around the input signal. This technique considerably reduces the SD-ADC's full-scale range, and notably relaxes the number of clock cycles needed for a given resolution, as well as the DC-gain and swing of the loop-filter. Both conversion time and power-efficiency can be improved, which results in a substantial improvement in energy-efficiency. Two BJT-based sensor prototypes based on 1st-order and 2nd-order zoom-ADCs are presented. They both achieve inaccuracies of less than ±0.2°C over the military temperature range (-55°C to 125°C). A prototype capable of sensing temperatures up to 200°C is also presented. As an alternative to BJTs, sensors based on dynamic threshold MOSTs (DTMOSTs) are also presented. It is shown that DTMOSTs are capable of achieving low inaccuracy (±0.4°C over the military temperature range) as well as sub-1V operation, making them well suited for use in modern CMOS processes.

• Presents a new readout technique (the zoom-ADC) to address the implementation of energy-efficient temperature sensors in CMOS technology;
• Shows how this technique can be used to design energy-efficient temperature sensors without compromising other key specifications, such as accuracy and resolution;
• Shows how this technique can be used to design general-purpose incremental ADCs that can achieve both high resolution and state-of-the-art energy efficiency;
• Presents DTMOST-based temperature sensors, which achieve significantly higher accuracy than previous all-CMOS temperature sensors.

Auteur

Dr. Kamran Souri received his M.Sc. (cum laude) from the Electronic Instrumentation Laboratory, Delft University of Technology, in 2009. Between 2009 and 2014 he was a Ph.D. candidate in the same faculty, focusing on the design of ultralow-power/energy-efficient CMOS smart temperature sensors for RFID applications. He is currently a Principal Circuit Designer with SiTime Corporation, Santa Clara, CA, USA, where he is working on circuit design for MEMS-based (temperature-compensated) oscillators. His current research interests include the design of low-power, energy-efficient sensor interfaces, data converters, precision mixed-signal and reference circuits.

Dr. Souri managed to improve the energy-efficiency of integrated temperature sensors by nearly two orders of magnitude, thus enabling the realization of practical temperature-sensing RFID (Radio Frequency Identification) tags. His work has resulted in one US Patent, many international publications and a number of commercial products. In Feb. 2013, he received the IEEE Solid-State Circuit Society Predoctoral Achievement Award. Dr. Souri has also served as a technical reviewer for the Journal of Solid-State Circuits (JSSC), the Journal of Analog Integrated Circuits and Signal Processing (AICSP), the IEEE Transactions on Circuits and Systems I (TCAS-I), the IEEE International Symposium on Circuits and Systems (ISCAS) and the Journal of Semiconductor Technology and Science (JSTS).

Prof. Dr. Kofi A. A. Makinwa received the B.Sc. (1st class honours) and M.Sc. degrees from Obafemi Awolowo University, Nigeria in 1985 and 1988 respectively. In 1989, he received the M.E.E. degree (cum laude) from the Philips International Institute, The Netherlands and in 2004, the Ph.D. degree from Delft University of Technology, The Netherlands.

From 1989 to 1999, he was a Research Scientist with Philips Research Laboratories, Eindhoven, The Netherlands, where he worked on interactive displays and digital recording systems. In 1999, he joined Delft University of Technology, where he is currently an Antoni van Leeuwenhoek Professor and Head of the Microelectronics Department. His main research interests are in the design of precision mixed-signal circuits, sigma-delta modulators, smart sensors and sensor interfaces. This has resulted in 12 books, 25 patents and over 200 publications.

Kofi Makinwa is the Analog Subcommittee Chair of the International Solid-State Circuits Conference (ISSCC). He also serves on the program committees of the VLSI Symposium, the European Solid-State Circuits Conference (ESSCIRC) and the Advances in Analog Circuit Design (AACD) workshop. He has been a three-time guest editor of the Journal of Solid-State Circuits (JSSC) and a distinguished lecturer of the IEEE Solid-State Circuits Society. For his doctoral research, he was awarded the 2005 Simon Stevin Gezel Award from the Dutch Technology Foundation. He is a co-recipient of 14best paper awards, from the JSSC, the ISSCC, the VLSI Symposium and Transducers, among others. At the 60th anniversary of ISSCC, he was recognized as a top-10 contributor. He is an IEEE Fellow, an alumnus of the Young Academy of the Royal Netherlands Academy of Arts and Sciences and an elected member of the IEEE Solid-State Circuits Society AdCom, the society's governing board.

Contenu

Introduction.- Readout Methods for BJT-Based Temperature Sensors.- Energy-Efficient BJT Readout.- BJT-Based, Energy-Efficient Temperature Sensors.- All-CMOS Precision Temperature Sensors.- Conclusions.- Summary.- Index.