Ultra-Low-Power Sensors and Receivers for IoT Applications

2019

Author : Haowei Jiang
Release : 2019
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Book Synopsis Ultra-Low-Power Sensors and Receivers for IoT Applications by : Haowei Jiang

Download or read book Ultra-Low-Power Sensors and Receivers for IoT Applications written by Haowei Jiang. This book was released on 2019. Available in PDF, EPUB and Kindle. Book excerpt: The combination of ultra-low power analog front-ends and CMOS-compatible transducers enable new applications, such as environmental monitors, household appliances, health trackers, etc. that are seamlessly integrated into our daily lives. Furthermore, wireless connectivity allows many of these sensors to operate both independently and collectively. These techniques collectively fulfil the recent surge of internet-of-things (IoT) applications that have the potential to fundamentally change daily life for millions of people. In this dissertation, the circuit and system design of wireless receivers and sensors is presented that explores the challenges of implementing long lifespan, high accuracy, and large coverage range IoT sensor networks. The first is a wake-up receiver (WuRX), which continuously monitors the RF environment to wake up a higher-power radio upon detection of a predetermined RF signature. This work both improves sensitivity and reduces power over prior art through a multi-faceted design featuring an impedance transformation network with large passive voltage gain, an active envelope detector with high input impedance to facilitate large passive voltage gain, a low-power precision comparator, and a low-leakage digital baseband correlator. Although pushing the prior WuRX performance boundary by orders of magnitude, the first work shows moderate sensitivity, inferior temperature robustness, and large area with external lumped components. Thus, the second work shows a miniaturized WuRX that is temperature-compensated, yet still consumes only nano-watt power and millimeter area while operating at 9 GHz. To further reduce the area, a global common-mode feedback is utilized across the envelope detector and baseband amplifier that eliminates the need for off-chip ac-coupling components. Multiple temperature-compensation techniques are proposed to maintain constant bandwidth of the signal path and constant clock frequency. Both WuRXs operate at 0.4 V supply, consume near-zero power and achieve ~-70 dBm sensitivity. Lastly, the first reported CMOS 2-in-1 relative humidity and temperature sensor is presented. A unified analog front-end interfaces on-chip transducers and converts the inputs into a frequency vis a high-linearity frequency-locked loop. An incomplete-settling switched-capacitor-based Wheatstone bridge is proposed to sense the inputs in a power-efficient fashion.

Ultra-Low Power Wireless Sensor Circuits for IOT Applications

2020

Author : Zhongxia Shang
Release : 2020
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Book Synopsis Ultra-Low Power Wireless Sensor Circuits for IOT Applications by : Zhongxia Shang

Download or read book Ultra-Low Power Wireless Sensor Circuits for IOT Applications written by Zhongxia Shang. This book was released on 2020. Available in PDF, EPUB and Kindle. Book excerpt: Wireless sensors, which are responsible for local data acquisition, processing and communication, play an important role in Internet of Things (IoT) applications. This research focuses on two basic components in wireless sensors, i.e., the low-power frequency tunable wireless receiver and the power management unit (PMU) for autonomous operation. In IoT applications, different sensors may need to operate in different frequency bands in order to meet environment constraints and industrial/medical standards. Thus, it is highly desirable to design a frequency configurable wireless receiver that provides flexibility in operation frequency. A 4-path filter based frequency shift keying (FSK) receiver is proposed to meet such a need, where the carrier frequency can be adjusted without changing the circuit. In addition, the proposed receiver requires no low-noise amplifier (LNA), which boosts the power efficiency. Frequency synthesizer is critical in FSK transceiver as it provides an accurate reference frequency. Based on 4-path mixer, a novel two-step calibration frequency synthesizer structure is proposed for low power consumption and wide locking range. Measurement results show that the proposed receiver achieves an energy per bit as 74pJ/bit with 2.5Mbps data rate and 184W power consumption. Post-layout simulation results show that the proposed frequency synthesizer has a figure of merit (FOM) value as 1.4W/MHz with 220MHz tuning bandwidth and 305W power consumption. Autonomous operation is another requirement for the sensors in many IoT applications, such as wearable sensors. Energy harvester is commonly used for autonomous sensors, where a PMU with low start-up voltage is necessary. To meet such a requirement, a novel controller for PMU is proposed to boost the power efficiency under very low load current. The proposed PMU can be started up with input voltage as low as several tens of millivolts. The novel controller costs little power and the overall efficiency is increased. Also, a hardware efficient maximum power point tracking (MPPT) algorithm which is suitable for energy source with fixed internal resistance is proposed. Measurement results show that the proposed system has a low controller power as 3.6W and the overall conversion efficiency is 83.9%.

Ultra-Low-Power and High-Sensitivity Wake-Up Receivers for IoT Applications

2020

Author : Po-Han Wang
Release : 2020
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Book Synopsis Ultra-Low-Power and High-Sensitivity Wake-Up Receivers for IoT Applications by : Po-Han Wang

Download or read book Ultra-Low-Power and High-Sensitivity Wake-Up Receivers for IoT Applications written by Po-Han Wang. This book was released on 2020. Available in PDF, EPUB and Kindle. Book excerpt: Wireless communication circuits often dominate the power consumption of Internet of Things (IoT) devices such as small battery-powered commercial wearables or low-power-wide-area-network (LPWAN) environmental sensors for infrastructure. More specifically, a large fraction of this power comes from node-to-hub or node-to-node networking requirements, especially when such devices communicate with low-to-medium average throughput. To reduce this power, instead of duty-cycling the main receiver, employing an auxiliary wake-up receiver (WuRX) that monitors the RF spectrum for a pre-defined wake-up signature either continuously or in duty-cycle fashion has been proved to be an effective solution. In this thesis, WuRX designs targeting ultra-low-power and high sensitivity for different usage scenarios are investigated. First, a WuRX for emerging LPWAN applications targeting to be used with the always-on WuRX communication protocol is presented. This design explores architecture-level and circuit-level techniques to operate with near-zero power consumption while achieving high sensitivity. Moreover, an active and a passive envelope detector (ED) that employ pseudo-balun architectures are also proposed, which further improve sensitivity and enable operation at a higher frequency band. On the other hand, WuRXs for commercial applications targeting to be used primarily with the duty-cycled WuRX communication protocol while being compatible with well-established wireless standards are also presented. First, a Bluetooth Low Energy (BLE) WuRX achieves low power, high sensitivity, interference-resiliency, and standard-compatibility through a combination of communication and circuit techniques, including high-Q filtering by a bank of FBAR resonators and a frequency-hopped mixer-first RF front-end that responds to a 4-dimensional (4-D) wake-up signature. This work is then further enhanced to achieve higher sensitivity while maintaining comparable interference-resiliency and power without the off-chip FBAR filters for a fully integrated solution. More importantly, this enhanced design is the first dual-mode WuRX compatible with both BLE and Wi-Fi transmitters, thanks to a carefully architected frequency plan that supports BLE advertisement channel hopping or a proposed subcarrier-based within-channel Wi-Fi frequency hopping scheme. As a result, the presented WuRX designs could potentially help enable new wireless IoT applications, particularly those that have low-to-medium average throughput requirements.

Ultra-Low Power FM-UWB Transceivers for IoT

2022-09-01 Technology & Engineering

Author : Vladimir Kopta
Release : 2022-09-01
Genre : Technology & Engineering
Kind : eBook
Book Rating : 490/5 ( reviews)

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Book Synopsis Ultra-Low Power FM-UWB Transceivers for IoT by : Vladimir Kopta

Download or read book Ultra-Low Power FM-UWB Transceivers for IoT written by Vladimir Kopta. This book was released on 2022-09-01. Available in PDF, EPUB and Kindle. Book excerpt: Over the past two decades we have witnessed the increasing popularity of the internet of things. The vision of billions of connected objects, able to interact with their environment, is the key driver directing the development of future communication devices. Today, power consumption as well as the cost and size of radios remain some of the key obstacles towards fulfilling this vision. Ultra-Low Power FM-UWB Transceivers for IoT presents the latest developments in the field of low power wireless communication. It promotes the FM-UWB modulation scheme as a candidate for short range communication in different IoT scenarios. The FM-UWB has the potential to provide exactly what is missing today. This spread spectrum technique enables significant reduction in transceiver complexity, making it smaller, cheaper and more energy efficient than most alternative options. The book provides an overview of both circuit-level and architectural techniques used in low power radio design, with a comprehensive study of state-of-the-art examples. It summarizes key theoretical aspects of FM-UWB with a glimpse at potential future research directions. Finally, it gives an insight into a full FM-UWB transceiver design, from system level specifications down to transistor level design, demonstrating the modern power reduction circuit techniques. Ultra-Low Power FM-UWB Transceivers for IoT is a perfect text and reference for engineers working in RF IC design and wireless communication, as well as academic staff and graduate students engaged in low power communication systems research.

Low Power Wireless Receivers for IoT Applications with Multi-band Calibration Algorithms

2021-04-03 Technology & Engineering

Author : Michael W. Rawlins
Release : 2021-04-03
Genre : Technology & Engineering
Kind : eBook
Book Rating : 286/5 ( reviews)

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Book Synopsis Low Power Wireless Receivers for IoT Applications with Multi-band Calibration Algorithms by : Michael W. Rawlins

Download or read book Low Power Wireless Receivers for IoT Applications with Multi-band Calibration Algorithms written by Michael W. Rawlins. This book was released on 2021-04-03. Available in PDF, EPUB and Kindle. Book excerpt: This book guides the reader through the design of circuits and wireless IoT devices deployed in applications demanding low power, small size, and high levels of integration. The design of a sub-1V wireless-LAN receiver is detailed along with associated calibration algorithms. Some of the key circuits detailed include a successive approximation analog-to-digital converter, a rail-to-rail comparator, a digitally programmable CMOS low-noise amplifier, an RF voltage to current converter, and a fifth-order Chebyshev analog programmable filter. Helpful appendices are included teaching operational amplifier design, CMOS and SiGe low-noise amplifier design, impedance matching, noise and distortion analysis. While theory and design equations are presented throughout the book for the various circuit designs, practical implementation and design tradeoffs are emphasized so the reader can immediately apply knowledge gained. Receiver and calibration circuits are designed in a standard CMOS technology using a 900mV power supply. Provides readers with analytical tools and practical help, conveyed in a clear and concise manner, which will assist not only in understanding the material, but also in practical and functional implementation of the concepts demonstrated; Focuses on long range and broad-band IoT applications with a wireless-LAN focus, emphasizing detailed design techniques, helping readers transition from theoretical understanding to practical application; Bridges the gap between system level understanding and practical design implementation, providing readers with tools and techniques which can be applied immediately to their designs; Serves as a handy technical resource for practical design techniques, as well as a quick reference guide for design equations and examples pertinent to realistic applications.

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