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.

This book describes the analysis and design of precision temperature sensors in CMOS IC technology, focusing on so-called smart temperature sensors, which provide a digital output signal that can be readily interpreted by a computer. The text shows how temperature characteristics can be used to obtain an accurate digital temperature reading. The book ends with a detailed description of three prototypes, one of which achieves the best performance reported to date.

This book describes the theory and design of high-accuracy CMOS smart temperature sensors. The major topic of the work is the realization of a smart temperature sensor that has an accuracy that is so high that it can be applied without any form of calibration. Integrated in a low-cost CMOS technology, this yields at the publication date of this book one of the most inexpensive intelligent general purpose temperature sensors in the world. The first thermometers could only be read by the human eye. The industrial revolution and the following computerization asked for more intelligent sensors, which could easily communicate to digital computers. This led to· the development of integrated temperature sensors that combine a bipolar temperature sensor and an A-to-D converter on the same chip. The implementation in CMOS technology reduces the processing costs to a minimum while having the best-suited technology to increase the (digital) intelligence. The accuracy of conventional CMOS smart temperature sensors is degraded by the offset of the read-out electronics. Calibration of these errors is quite expensive, however, dynamic offset-cancellation techniques can reduce the offset of amplifiers by a factor 100 to 1000 and do not need trimming. Chapter two gives an elaborate description of the different kinds of dynamic offset-cancellation techniques. Also a new technique is introduced called the nested chopper technique. An implementation of a CMOS nested-chopper instrumentation amplifier shows a residual offset of less than lOOn V, which is the best result reported to date.

Thermal Sensors is intended as a comprehensive and accessible reference for designers and users of thermal sensors. Many different physical quantities can be converted easily and accurately into temperature differences using thermal techniques. These temperature differences can be detected with temperature and temperature-difference sensors. In a thermal sensor the thermal converter and the temperature sensor are combined in a single accurate device. This book gives an overview and deals with the design aspects of thermal and temperature sensors, with an emphasis on sensors based on silicon technology. The temperature sensors described are based on the use of various types of sensitive elements, such as platinum resistors, thermistors and special integrated circuits. The thermal sensors described include flow, conductivity, infrared, vacuum, humidity and calorimetric sensors, and ac-dc converters, thus providing a comprehensive overview of all thermal sensors, with practical examples of each type.

This book describes the design and theory of high-accuracy smart temperature sensors in CMOS technology. The book's major triumph is the realization of a smart temperature sensor of such high accuracy that it can be applied without any form of calibration. In addition, the authors provide the reader with an elaborate overview of dynamic offset-cancellation techniques and CMOS bandgap references, which are the basic techniques and building blocks that determine the overall accuracy of CMOS smart temperature sensors. The book's concluding chapters focus on realizations where other aspects like ultra low-design and remote temperature sensing are discussed. High-Accuracy CMOS Smart Temperature Sensors is essential reading for anybody with an academic or professional interest in semiconductor design.

This book describes the background, principles, implementations, characterization, and future trends of temperature sensors made from silicon resistors in CMOS technology, including their readout circuits. Readers will benefit from the latest research of CMOS temperature sensors, and could learn about various precision analog techniques such as phase detection, continuous-time ΔΣ ADC, zoom ADC, FIR-DAC, dynamic element matching, OTA linearization, etc.

This book presents innovative solutions in the design of precision instrumentation amplifier and read-out ICs, which can be used to boost millivolt-level signals transmitted by modern sensors, to levels compatible with the input ranges of typical Analog-to-Digital Converters (ADCs). The discussion includes the theory, design and realization of interface electronics for bridge transducers and thermocouples. It describes the use of power efficient techniques to mitigate low frequency errors, resulting in interface electronics with high accuracy, low noise and low drift. Since this book is mainly about techniques for eliminating low frequency errors, it describes the nature of these errors and the associated dynamic offset cancellation techniques used to mitigate them.