Interface Circuits for Microsensor Integrated Systems

ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms. [Recent advances in sensing technologies, especially those for Microsensor Integrated Systems, have led to several new commercial applications. Among these, low voltage and low power circuit architectures have gained growing attention, being suitable for portable long battery life devices. The aim is to improve the performances of actual interface circuits and systems, both in terms of voltage mode and current mode, in order to overcome the potential problems due to technology scaling and different technology integrations. Related problems, especially those concerning parasitics, lead to a severe interface design attention, especially concerning the analog front-end and novel and smart architecture must be explored and tested, both at simulation and prototype level. Moreover, the growing demand for autonomous systems gets even harder the interface design due to the need of energy-aware cost-effective circuit interfaces integrating, where possible, energy harvesting solutions. The objective of this Special Issue is to explore the potential solutions to overcome actual limitations in sensor interface circuits and systems, especially those for low voltage and low power Microsensor Integrated Systems. The present Special Issue aims to present and highlight the advances and the latest novel and emergent results on this topic, showing best practices, implementations and applications. The Guest Editors invite to submit original research contributions dealing with sensor interfacing related to this specific topic. Additionally, application oriented and review papers are encouraged.

SIRU development. Volume 1: System development

A complete description of the development and initial evaluation of the Strapdown Inertial Reference Unit (SIRU) system is reported. System development documents the system mechanization with the analytic formulation for fault detection and isolation processing structure; the hardware redundancy design and the individual modularity features; the computational structure and facilities; and the initial subsystem evaluation results

12.8 kHz Energy-Efficient Read-Out IC for High Precision Bridge Sensor Sensing System

학위논문(박사) -- 서울대학교대학원 : 공과대학 전기·정보공학부, 2022.2. 김수환.In the thesis, a high energy-efficient read-out integrated circuit (read-out IC) for a high-precision bridge sensor sensing system is proposed. A low-noise capacitively-coupled chopper instrumentation amplifier (CCIA) followed by a high-resolution incremental discrete-time delta-sigma modulator (DTΔΣΜ) analog-to-digital converter (ADC) is implemented. To increase energy-efficiency, CCIA is chosen, which has the highest energy-efficiency among IA types. CCIA has a programmable gain of 1 to 128 that can amplify the small output of the bridge sensor. Impedance boosting loop (IBL) is applied to compensate for the low input impedance, which is a disadvantage of a CCIA. Also, the sensor offset cancellation technique was applied to CCIA to eliminate the offset resulting from the resistance mismatch of the bridge sensor, and the bridge sensor offset from -350 mV to 350 mV can be eliminated. In addition, the output data rate of the read-out IC is designed to be 12.8 kHz to quickly capture data and to reduce the power consumption of the sensor by turning off the sensor and read-out IC for the rest of the time. Generally, bridge sensor system is much slower than 12.8 kHz. To suppress 1/f noise, system level chopping and correlated double sampling (CDS) techniques are used. Implemented in a standard 0.13-μm CMOS process, the ROIC’s effective resolution is 17.0 bits at gain 1 and that of 14.6 bits at gain 128. The analog part draws the average current of 139.4 μA from 3-V supply, and 60.2 μA from a 1.8 V supply.본 논문에서는 고정밀 브리지 센서 센싱 시스템을 위한 에너지 효율이 높은 Read-out Integrated Circuit (read-out IC)를 제안한다. 저 잡음 Capacitively-Coupled Instrumentation Amplifier (CCIA)에 이은 고해상도 Discrete-time Delta-Sigma 변조기(DTΔΣΜ) 아날로그-디지털 변환기(ADC)를 구현하였다. 에너지 효율을 높이기 위해 IA 유형 중 에너지 효율이 가장 높은 CCIA를 선택하였다. CCIA는 브리지 센서의 작은 출력을 증폭할 수 있는 1 에서 128의 프로그래밍 가능한 전압 이득을 가진다. CCIA의 단점인 낮은 입력 임피던스를 보상하기 위해 Impedance Boosting Loop (IBL)을 적용하였다. 또한 CCIA에 센서 오프셋 제거 기술을 적용하여 브리지 센서의 저항 미스매치로 인한 오프셋을 제거 기능을 탑재하였으며 -350mV에서 350mV까지 브리지 센서 오프셋을 제거할 수 있다. Read-out IC의 출력 데이터 전송률은 12.8kHz로 설계하여 데이터를 빠르게 채고 나머지 시간 동안 센서와 read-out IC를 꺼서 센서의 전력 소비를 줄일 수 있도록 설계하였다. 일반적으로 브리지 센서 시스템은 12.8kHz보다 느리기 때문에 이것이 가능하다. 하지만, 일반적인 CCIA는 입력 임피던스 때문에 빠른 속도에서 설계가 불가능하다. 이를 해결하기 위해 demodulate 차핑을 앰프 내부가 아닌 시스템 차핑을 이용해 해결하였다. 1/f 노이즈를 억제하기 위해 시스템 레벨 차핑 및 상관 이중 샘플링(CDS) 기술이 사용되었다. 0.13μm CMOS 공정에서 구현된 read-out IC의 Effective Resolution (ER)은 전압 이득 1에서 17.0비트이고 전압 이득 128에서 14.6비트를 달성하였다. 아날로그 회로는 3 V 전원에서 139.4μA의 평균 전류를, 디지털 회로는 1.8 V 전원에서 60.2μA의 평균 전류를 사용한다.CHAPTER 1 INTRODUCTION 1 1.1 SMART DEVICES 1 1.2 SMART SENSOR SYSTEMS 4 1.3 WHEATSTONE BRIDGE SENSOR 5 1.4 MOTIVATION 8 1.5 PREVIOUS WORKS 10 1.6 INTRODUCTION OF THE PROPOSED SYSTEM 14 1.7 THESIS ORGANIZATION 16 CHAPTER 2 SYSTEM OVERVIEW 17 2.1 SYSTEM ARCHITECTURE 17 CHAPTER 3 IMPLEMENTATION OF THE CCIA 19 3.1 CAPACITIVELY-COUPLED CHOPPER INSTRUMENTATION AMPLIFIER 19 3.2 IMPEDANCE BOOSTING 22 3.3 SENSOR OFFSET CANCELLATION 25 3.4 AMPLIFIER OFFSET CANCELLATION 29 3.5 AMPLIFIER IMPLEMENTATION 32 3.6 IMPLEMENTATION OF THE CCIA 35 CHAPTER 4 INCREMENTAL ΔΣ ADC 37 4.1 INTRODUCTION OF INCREMENTAL ΔΣ ADC 37 4.2 IMPLEMENTATION OF INCREMENTAL ΔΣ MODULATOR 40 CHAPTER 5 SYSTEM-LEVEL DESIGN 43 5.1 DIGITAL FILTER 43 5.2 SYSTEM-LEVEL CHOPPING & TIMING 46 CHAPTER 5 MEASUREMENT RESULTS 48 6.1 MEASUREMENT SUMMARY 48 6.2 LINEARITY & NOISE MEASUREMENT 51 6.3 SENSOR OFFSET CANCELLATION MEASUREMENT 57 6.4 INPUT IMPEDANCE MEASUREMENT 59 6.5 TEMPERATURE VARIATION MEASUREMENT 63 6.6 PERFORMANCE SUMMARY 66 CHAPTER 7 CONCLUSION 68 APPENDIX A. 69 ENERGY-EFFICIENT READ-OUT IC FOR HIGH-PRECISION DC MEASUREMENT SYSTEM WITH IA POWER REDUCTION TECHNIQUE 69 BIBLIOGRAPHY 83 한글초록 87박

Radiation-Hardened Data Acquisition System Based on a Mask-programmable Analog Array

Data acquisition systems capable of extreme temperature and radiation environments are of dire need in an era of great nuclear energy generation. Efforts to respond to recent nuclear accidents, such as those caused by natural disasters at Fukushima, have suffered in promptness and effectiveness due to the lack of information gathered from these sites. Currently, there are no systems available that accurately acquire, digitize, and remotely report this data in the presence of harsh radiation. Using a mask-programmable analog array prototype chip designed for Triad Semiconductor and an FMI frequency synthesizer, both verified to beyond 300 kRad and 125ºC and capable of analog signal conditioning and digitization, a radiation-hardened data acquisition system is produced. This system will report three parameters of importance to the assessment of a nuclear reactor environment: gamma radiation, temperature, and pressure. Through a three-task development process, the discrete part selection and overall system will be outlined, detailed board design will be shown, and end-to-end system calibration and radiation testing will be performed and analyzed. The evaluation of target environments will provide specifications for system performance, as well as determine successful completion of the work

A Network Camera with a Nose

Some network cameras have already several other sensors besides the image sensor to extend the capabilities of the camera. It is then only natural to think what can be achieved when air sensors are added into the mix. In this master thesis the applications of air sensors coupled together with network cameras have been investigated. Considering the network infrastructure is already in place, having camera units collecting air quality data is certainly attractive in cities where pollution is a problem. Not only will it help localise the source, it will also aid urban planning. Of course, this is only one of the many application areas of air sensors. Having accurate data is also important as the price of air sensors usually have a relation with their accuracy. Two prototypes for an low-cost NO2 electrochemical sensor, Alphasense NO2-B43F, were built that can be connected to a I/O-interface of a network camera for data transmission and power. Another low-cost sensor, the Alphasense OPC-N2, was evaluated, as measurement of particles are interesting. The evaluation was based on comparison with the more expensive counterparts of the low-cost sensor. Climate test were performed for the Alphasense NO2-B43F. It was concluded that these low-cost sensors have many uncertainties and require various tests, such as long term tests and precision tests. From the performed tests and comparison, the Alphasense NO2-B43F has shown to correlate well enough with the reference measurements to have the potential to supplement the reference with local measurements. The transmission of data and power through a network camera has been successful with the prototype.En nätverkskamera med en näsa Dagens nätverkskameror innehåller i många fall redan idag flera sensorer utöver bildsensorer. De kan ta upp ljud och känna vibrationer bland annat. Utöver detta, kan en gassensor också vara ett komplement? Lågkostnadssensorer för gasmätning är något som börjar att sticka upp på marknaden och öppnar upp för många applikationer. De lägre priserna möjliggör även att de kan integreras i uppkopplade enheter som nätverkskameror utan att produkternas kostnad sticker iväg allt för mycket. Funktionaliteter som kan komplettera kameran är bland annat att detektera när hälsokritiska nivåer av gaser i slutna utrymmen, såsom industrilokaler eller gruvor. Gassensorer kan även detektera mänsklig närvaro genom att analysera förändringar av koldioxidhalten i rummet, detta kan vara relevant i situationer där bildsensorn inte har en heltäckande vy. En annan applikation för gassensorer är att samla in data om hur luften ser ut i världen där vi rör oss. I begreppet luftkvalitet ingår även halter av partiklar. Idag har de flesta kommuner mellan 1-5 mätstationer där de mäter luftkvalitet och detta ger en viss översikt, men det kan finnas stora lokala variationer. Nätverkskameror finns idag överallt i miljöer där vi rör oss och ofta i anslutning till trafikleder. Att då komplettera dessa med en luftkvalitetssensor istället för att ha en separat enhet som också behöver ström och nätverk vore ett kostnadseffektivt sätt att få en bättre bild över de lokala utsläppsnivåerna. Lågkostnadssensorer för mätning av gaser och partiklar som är tillräckligt bra för att utvärdera luftkvaliteten i utomhusmiljöer finns redan idag, i alla fall enligt specifikationerna som står i tillverkarnas datablad. Men hur presterar de i verkligheten? För att få en indikation om detta jämfördes två lågkostnadsenheter, en kvävedioxidsensor och en mätare för partikelmasskoncentration med avsevärt dyrare referenser. Lågkostnadsenheterna som utvärderades visade en tydlig korrelation mot referenserna vilket tyder på att enheterna redan idag kan vara mogna för att ge kompletterande luftkvalitetsdata. Vidare och mer ingående studier behöver dock göras innan ett definitivt uttalande kan göras. Andra aspekter som bör undersökas är hur sensorerna påverkas av omgivande faktorer som luftfuktighet och vindar. Kan detta karakteriseras är det möjligt att förbättra mätresultaten ytterligare

Integrated Circuits and Systems for Smart Sensory Applications

Connected intelligent sensing reshapes our society by empowering people with increasing new ways of mutual interactions. As integration technologies keep their scaling roadmap, the horizon of sensory applications is rapidly widening, thanks to myriad light-weight low-power or, in same cases even self-powered, smart devices with high-connectivity capabilities. CMOS integrated circuits technology is the best candidate to supply the required smartness and to pioneer these emerging sensory systems. As a result, new challenges are arising around the design of these integrated circuits and systems for sensory applications in terms of low-power edge computing, power management strategies, low-range wireless communications, integration with sensing devices. In this Special Issue recent advances in application-specific integrated circuits (ASIC) and systems for smart sensory applications in the following five emerging topics: (I) dedicated short-range communications transceivers; (II) digital smart sensors, (III) implantable neural interfaces, (IV) Power Management Strategies in wireless sensor nodes and (V) neuromorphic hardware

Application of imaging pyrometry for remote temperature measurements

The radiometric model of an IR image sensor has been developed. Based on this model, the application of imaging pyrometry to remote temperature measurements has been investigated. This analysis provides the estimation of temperature accuracy achievable by imaging pyrometry in conjunction with a number of radiometric methods. The detection of radiation emitted across the full spectral bandwidth of the imager as well as utilization of narrow-passband filters was analyzed for a target with known emissivity. The methods of two-wavelength ratio radiometry and multi-wavelength radiometry were considered for the targets with unknown emissivity. The optimal selection of the wavelengths for the method of ratio radiometry was investigated. It was shown that in the case of a blackbody radiator at 1000 °C the ratio radiometry yields temperature resolution of 0.5 °C for the 106 electrons per pixel signal level detected by 320x244 IR imager with PtSi Schottky-barrier detectors and operated with 100-nm-wide Gaussian filters positioned at 1.5 μm and 3.0 µ. The temperature accuracy achievable by least-squares-based multi-wavelength imaging pyrometry (MWIP) was analyzed for linear and quadratic emissivity models. The presented results have shown that for targets with quadratic spectral emissivity at 1000 °C the 6-filter MWIP is capable of providing temperature resolution of about 1 °C for target temperature of 1000 °C and the maximum signal of 4x106 electrons per pixel. For targets at 500 °C the corresponding accuracy is equal to 0.4 °C

Three Realizations and Comparison of Hardware for Piezoresistive Tactile Sensors

Tactile sensors are basically arrays of force sensors that are intended to emulate the skin in applications such as assistive robotics. Local electronics are usually implemented to reduce errors and interference caused by long wires. Realizations based on standard microcontrollers, Programmable Systems on Chip (PSoCs) and Field Programmable Gate Arrays (FPGAs) have been proposed by the authors for the case of piezoresistive tactile sensors. The solution employing FPGAs is especially relevant since their performance is closer to that of Application Specific Integrated Circuits (ASICs) than that of the other devices. This paper presents an implementation of such an idea for a specific sensor. For the purpose of comparison, the circuitry based on the other devices is also made for the same sensor. This paper discusses the implementation issues, provides details regarding the design of the hardware based on the three devices and compares them.This work has been partially funded by the Spanish Government under contracts TEC2006-12376 and TEC2009-14446

A wireless RF CMOS mixed-signal interface for soil moisture measurements

This paper describes a wireless RF CMOS interface for soil moisture measurements. The interface basically comprises a Delta-Sigma (ΔΣ) modulator for acquiring an external sensor signal, and a RF section where data is transmitted to a local processing unit. The ΔΣ modulator is a single-bit, second-order modulator and it is implemented using switched-capacitors techniques in a fully-differential topology. With a sampling frequency of 423.75 kHz and an oversampling ratio (OSR) of 256, the modulator achieves a dynamic range of 98.7 dB (16.1 bit). The output of the modulator is applied to a counter, as a first-order decimation filter, and the result is stored. Prior to transmission, data is encoded as a pulse width modulated signal and assembled in a frame containing preamble and checksum control fields. This frame is then transmitted through a power amplifier operating at 433.92 MHz in class-E mode. To evaluate the ΔΣ modulator performance, the bitstream was acquired and transferred to a personal computer to perform digital filtering and decimation using MATLAB. The soil moisture sensor is based on dual-probe heat-pulse (DPHP) method and is implemented by using an integrated temperature sensor and a heater. After applying a heat-pulse for a fixed period of time, the temperature rise, that is a function of soil moisture, generates a differential voltage that is amplified and applied to the mixed-signal interface input. The described interface can also be used with other kinds of environmental sensors in a wireless sensors network. The CMOS mixed-signal interface has been implemented in a single-chip using a standard CMOS 0.7 μm process (AMI C07M-A, n-well, 2 metals and 1 poly)