Extreme Low Power Research Articles

P‐75: Extreme Low Power a‐InGaZnO TFT Scan Driver with Extra Clock Signal Modulation

In this paper, a scan driver with extra clock signal using amorphous indium‐gallium‐zinc‐oxide (a‐InGaZnO) thin‐film transistors (TFTs) is proposed. Extra clock signal with variable frequency modulates the pull‐down unit of scan driver in order to reduce the power consumption. Proposed scan driver is suitable for operating extreme low‐power displays such as always on display.

A High Aperture Efficiency 1-bit Reconfigurable Reflectarray Antenna With Extremely Low Power Consumption

A High Aperture Efficiency 1-bit Reconfigurable Reflectarray Antenna With Extremely Low Power Consumption

Optimized design of an extreme low power datalogger for photovoltaic panels

<span lang="EN-US">The paper focuses on the design and implementation of a low cost and compact data logger prototype using an extreme low power (XLP) and low pin count programmable interface controllers (PIC) microcontroller using its own flash memory for the periodic data acquisition storage, while many other works focus in the Arduino Eco-system. It is planned to pick four important analog measures from the photovoltaic system, and store them directly as 10-bit numerical counts, this yields to faster data acquisition and storage (no time consuming for mathematical computation to convert each numerical count of raw data to meaningful real-world data). Avoiding the use of any kind of display and keypad, and keeping the ratio run time over sleep time as low as possible, has a maximum impact on lowering the power consumption. This prototype can be serially linked to a personal computer (PC) to view the acquisition of measurements in real time, and to retrieve all collected data through a terminal application. The experimental results are stored in comma-separated values (CSV) files to ease post data analysis with any spread sheet software, for statistical calculations and graphs drawing, in order for instance, to find the faults of the photovoltaic system and optimize its management and its performance.</span>

Communication by Means of Thermal Noise: Toward Networks With Extremely Low Power Consumption

In this paper, the paradigm of thermal noise communication (TherCom) is put forward for future wired/wireless networks with extremely low power consumption. Taking backscatter communication (BackCom) and reconfigurable intelligent surface (RIS)-based radio frequency chain-free transmitters one step further, a thermal noise-driven transmitter might enable zero-signal-power transmission by simply indexing resistors or other noise sources according to information bits. This preliminary paper aims to shed light on the theoretical foundations, transceiver designs, and error performance derivations as well as optimizations of two emerging TherCom solutions: Kirchhoff-law-Johnson-noise (KLJN) secure bit exchange and wireless thermal noise modulation (TherMod) schemes. Our theoretical and computer simulation findings reveal that noise variance detection, supported by sample variance estimation with carefully optimized decision thresholds, is a reliable way of extracting the embedded information from noise modulated signals, even with limited number of noise samples.

Stern-Gerlach effect of vector light bullets in a nonlocal Rydberg medium.

We show that stable (3+1)-dimensional vector light bullets with ultraslow propagating velocity and extreme low generation power can be realized in a cold Rydberg atomic gas. They can also be actively controlled by using a nonuniform magnetic field; especially, trajectories of their two polarization components can have significant Stern-Gerlach deflections. The results obtained are useful for revealing the nonlocal nonlinear optical property of Rydberg media and for measuring weak magnetic fields.

Monitoring Heart Rate Variability Based on Self-powered ECG Sensor Tag

This paper proposes a batteryless sensing and computational device to collect and process electrocardiography (ECG) signals for monitoring heart rate variability (HRV). The proposed system comprises of a passive UHF radio frequency identification (RFID) tag, an extreme low power microcontroller, a low-power ECG circuit, and a radio frequency (RF) energy harvester. The microcontroller and ECG circuits consume less power of only ~30 µA and ~3 mA, respectively. Therefore, the proposed RF harvester operating at frequency band of 902 - 928 MHz can sufficiently collect available energy from the RFID reader to supply power to the system within a maximum distance of ~2 m. To extract R-peak of the ECG signal, a robust algorithm that consumes less time processing is also developed. The information of R-peaks is stored into an Electronic Product Code (EPC) Class 1st Generation 1st compliant ID of the tag and read by the reader. This reader is functioned to collected the R-peak data with sampling rate of 100ms; therefore, the user application can monitor fully range of HRV. The performance of the proposed system shows that this study can provide a good solution in paving the way to new classes of healthcare applications.

Changes in photovoltaic potential over China in a warmer future

Solar photovoltaic (PV) technology offers a promising path for addressing energy demand and mitigating climate change. However, climatic conditions relevant to the productivity of solar power may be changed in a warmer future. Here, we quantify the impact of climate change on PV potential over China based on high-resolution climate projections within the framework of the Coordinated Regional Climate Downscaling Experiment (CORDEX). Our results indicate that the annual mean PV power potential (PV POT) over China would decrease by several percent relative to the reference period (1986–2005) under a warmer climate, with the most pronounced decrease over the Tibetan Plateau, which is currently the most solar-rich region in China. However, beyond changes in the mean climate state, we demonstrate a substantial increase in events of extreme low PV power outputs (i.e. those falling below the 10th percentile of the probability distribution of the daily PV POT anomalies). For instance, the frequency of extreme low PV events is projected to reach nearly three times the reference period level over the Tibetan Plateau under the scenario of 3 °C global warming (similar to late-century warming projected based on current mitigation policies). Future changes in PV POT are dominated by changes in surface solar irradiance, while the warming condition further exacerbates the decrease in PV POT. Our results highlight that both the mean and extreme conditions of solar inputs should be considered simultaneously when assessing the impacts of climate change on PV power outputs.

Demonstration of Anti-ambipolar Switch and Its Applications for Extremely Low Power Ternary Logic Circuits.

Anti-ambipolar switch (AAS) devices at a narrow bias region are necessary to solve the intrinsic leakage current problem of ternary logic circuits. In this study, an AAS device with a very high peak-to-valley ratio (∼106) and adjustable operating range characteristics was successfully demonstrated using a ZnO and dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene heterojunction structure. The entire device integration was completed at a low thermal budget of less than 200 °C, which makes this AAS device compatible with monolithic 3D integration. A 1-trit ternary full adder designed with this AAS device exhibits excellent power–delay product performance (∼122 aJ) with extremely low power (∼0.15 μW, 7 times lower than the reference circuit) and lower device count than those of other ternary device candidates.

Unlocking the Hidden Dimension of the World’s Transmission and Distribution Power Losses through Fractal Statistical Inference

Various studies on the transmission and distribution power losses had been conducted but a global view of the transmission and distribution power loss rates had not been explored yet. This paper explained the fractal dimension of the global distribution and transmission power losses using fractal statistical analysis. Findings revealed that the computed fractal dimension of 1.08 means that power losses of countries across the globe deviated from uniformity by about 8 percent. The upper and bottom eight (8) percent of the dataset were analyzed and findings revealed that the ruggedness of the phenomenon was attributable to political and economic dimensions. The extreme high distribution and transmission power losses may be traced back to chaos, pilferage, and substandard materials. On the other hand, the economic stability and state control capacity contributed much to the extreme low distribution and transmission power losses. Keywords: fractal analysis, power loss, power transmission and distribution, xfractal.

Self-Powered Point-of-Care Device for Galvanic Cell-Based Sample Concentration Measurement

A novel self-powered point-of-care low-power electronics approach for galvanic cell-based sample concentration measurement is presented. The electronic system harvests and senses at the same time from the single cell. The system implements a solution that is suitable in those scenarios where extreme low power is generated from the fuel cell. The proposed approach implements a capacitive-based method to perform a non-linear sweep voltammetry to the cell, but without the need to implement a potentiostat amplifier for that purpose. It provides a digital-user readable result without the need for external non-self-powered devices or instruments compared with other solutions. The system conception was validated for a particular case. The scenario consisted of the measurement of a NaCl solution as the electrolyte, which was related to the conductivity of the sample. The electronic reader continuously measured the current with a transfer function gain of −1. The overall system exhibited a maximum coefficient of variation of %, which was an improvement compared with the state-of-the-art. The proof of concept of this electronics system was validated with a maximum power consumption of using commercial-off-the-self parts.

A New Extremely Low Power Temperature Insensitive Electronically Tunable VCII-Based Grounded Capacitance Multiplier

In this brief, a new circuit topology to realize an electronically tunable grounded capacitor multiplier with extremely low power consumption and low supply voltage requirement is investigated. The proposed circuit uses an electronically tunable second generation voltage conveyor (VCII) and a single floating capacitor. Owing to the translinear principle, current gain of VCII is varied through a control current and, as a result, the value of simulated capacitor is also varied. Favorably the obtained gain is temperature insensitive. Both of the required supply voltage and control currents are very low because all transistors are biased in subthreshold region: therefore, electronic tunability is achieved while the power consumption is kept at very low value. In addition, the circuit realization is very simple since only twelve transistors are required. Simulation results, performed at schematic level in 0.18 $\mu \text{m}$ CMOS technology and supply voltage of ±0.3V, are presented. It is shown that a multiplication factor from 1 to 100 is possible while the power consumption varies from 10 nW to 67 nW.

Adaptive Backoff enabled WUR on non-cellular local IoT for extreme low power operation

A large number of edge devices employed for Internet of Things (IoT) technology require low-power operation to extend operating time. However, contention-based networks may cause channel collisions and throughput degradation as the number of devices increases. Furthermore, in a competition-based network in which different IoT devices coexist, one common channel access algorithm is required for effective spectrum access. Therefore, we propose an adaptive backoff enabled MAC operation of a common channel access algorithm for edge devices with different MAC protocols in a local IoT wireless environment to reduce power consumption and channel access latency. The discrete-event simulation results demonstrate that the proposed channel access scheme outperforms the existing EDCA channel access schemes in general MAC under different scenarios such as traffic load and packet arrival rate.

Large-Scale Wireless-Powered Networks With Backscatter Communications—A Comprehensive Survey

Massive and ubiquitous deployment of devices in networks of fifth generation (5G) and beyond wireless has necessitated the development of ultra-low-power wireless communication paradigms. Recently, wireless-powered networks with backscatter communications (WPN-BCs) has been emerged as a most prominent technology for enabling large-scale self-sustainable wireless networks with the capabilities of RF energy harvesting (EH) and of extreme low power consumption. Therefore, we provide a comprehensive literature review on the fundamentals, challenges and the on-going research efforts in the domain of WPN-BCs. Our emphasis is on large-scale networks. In particular, we discuss signal processing aspects, network design issues and efficient communication techniques. Moreover, we review emerging technologies for WPN-BCs to bring about the best use of resources. Some applications of this innovative technology are also highlighted. Finally, we address some open research problems and future research directions.

Bayesian Estimation for Item Factor Analysis Models with Sparse Categorical Indicators

ABSTRACTPsychometric models for item-level data are broadly useful in psychology. A recurring issue for estimating item factor analysis (IFA) models is low-item endorsement (item sparseness), due to limited sample sizes or extreme items such as rare symptoms or behaviors. In this paper, I demonstrate that under conditions characterized by sparseness, currently available estimation methods, including maximum likelihood (ML), are likely to fail to converge or lead to extreme estimates and low empirical power. Bayesian estimation incorporating prior information is a promising alternative to ML estimation for IFA models with item sparseness. In this article, I use a simulation study to demonstrate that Bayesian estimation incorporating general prior information improves parameter estimate stability, overall variability in estimates, and power for IFA models with sparse, categorical indicators. Importantly, the priors proposed here can be generally applied to many research contexts in psychology, and they do not impact results compared to ML when indicators are not sparse. I then apply this method to examine the relationship between suicide ideation and insomnia in a sample of first-year college students. This provides an important alternative for researchers who may need to model items with sparse endorsement.

An AdaBoost-Based Face Detection System Using Parallel Configurable Architecture With Optimized Computation

With the development of image sensor technology, the AdaBoost-based face detections are widely used in many monitoring sensor networks and mobile-camera-based applications. Fast face detection with high detection accuracy and low power consumption in such kinds of applications is very important. Since the AdaBoost-based face detection exhibits characteristics of data computation in dual direction and data diversity, we propose an AdaBoost-based face detection system using parallel configurable architecture with optimized computation. The architecture consists of parallel configurable arrays and two-level shared memory systems. It achieves dual-direction-based integral image computation that improves parallel processing efficiency and enables the subwindow adaptive cascade classification for data diversity, which further improves the detection efficiency in diverse face detection. Compared with the state-of-the-art works, this work achieves maximal performance of 30 frames/s at 1080p detection speed and extreme low power consumption.

Design of an Active Inductor-Based T/R Switch in 0.13 μm CMOS Technology for 2.4 GHz RF Transceivers

A high-performance transmit/receive (T/R) switch is essential for every radio-frequency (RF) device. This paper proposes a T/R switch that is designed in the CEDEC 0.13 μm complementary metal-oxide-semiconductor (CMOS) technology for 2.4 GHz ISM-band RF applications. The switch exhibits a 1 dB insertion loss, a 28.6 dB isolation, and a 35.8 dBm power-handling capacity in the transmit mode; meanwhile, for the 1.8 V/0 V control voltages, a 1.1 dB insertion loss and a 19.4 dB isolation were exhibited with an extremely-low power dissipation of 377.14 μW in the receive mode. Besides, the variations of the insertion loss and the isolation of the switch for a temperature change from - 25℃ to 125℃ are 0.019 dB and 0.095 dB, respectively. To obtain a lucrative performance, an active inductor-based resonant circuit, body floating, a transistor W/L optimization, and an isolated CMOS structure were adopted for the switch design. Further, due to the avoidance of bulky inductors and capacitors, a very small chip size of 0.0207 mm2 that is the lowest-ever reported chip area for this frequency band was achieved.

Micropower Mixed-signal VLSI Independent Component Analysis for Gradient Flow Acoustic Source Separation.

A parallel micro-power mixed-signal VLSI implementation of independent component analysis (ICA) with reconfigurable outer-product learning rules is presented. With the gradient sensing of the acoustic field over a miniature microphone array as a pre-processing method, the proposed ICA implementation can separate and localize up to 3 sources in mild reverberant environment. The ICA processor is implemented in 0.5 µm CMOS technology and occupies 3 mm × 3 mm area. At 16 kHz sampling rate, ASIC consumes 195 µW power from a 3 V supply. The outer-product implementation of natural gradient and Herault-Jutten ICA update rules demonstrates comparable performance to benchmark FastICA algorithm in ideal conditions and more robust performance in noisy and reverberant environment. Experiments demonstrate perceptually clear separation and precise localization over wide range of separation angles of two speech sources presented through speakers positioned at 1.5 m from the array on a conference room table. The presented ASIC leads to a extreme small form factor and low power consumption microsystem for source separation and localization required in applications like intelligent hearing aids and wireless distributed acoustic sensor arrays.

D2ART: Direct Data Accessing from Passive RFID Tag for infra-less, contact-less, and battery-less pervasive computing

A wireless IoT device is getting more and more popular. The device may communicate with other devices without any communication infrastructure whenever these devices are sufficiently close. In view of energy consumption, this approach, i.e., infra-less communication is considerably cheaper and more efficient since energy dissipation grows with at least the square of the distance. With this “energy wise” approach, battery-less and contact-less communication nodes are becoming increasingly attractive for future pervasive computing. In this paper, we study important design considerations and technical limitations for realizing such a device, and then we propose D2ART (Direct Data Accessing from Passive RFID Tag) that not only performs as a normal passive RFID tag for identification, but also provides rich information such as multimedia to a reader with extreme low power consumption. Our fabricated D2ART IC is operational within 7–8 cm at data transmission rate of 5 Mbps by interfacing with a conventional flash memory according to the measurement and post-layout simulation results with reasonable assumptions.

A Novel Low Power Bitcell Design Featuring Inherent SEU Prevention and Self Correction Capabilities

The pursuit of continuous scaling of electronic devices in the semiconductor industry has led to two unintended but significant outcomes: a rapid increase in susceptibility to radiation induced errors, and an overall rise in power consumption. Operating under low voltage to reduce power only aggravates radiation related reliability issues. The proposed “SEU Hardening Incorporating Extreme Low Power Bitcell Design” (SHIELD) addresses these two major concerns simultaneously. It is based on the concept of gating the conventional cross-coupled inverters while introducing a novel “cut-off” network. This creates redundant storage nodes and eliminates the internal feedback loop during radiation particle impact. The SHIELD bitcell tolerates upsets with charge deposits over 1 pC. Simulations confirm its advantages in terms of leakage power, with more than twofold lower leakage currents than previous solutions when operated at a 700mV supply voltage in a 65 nm process. To validate the bitcell’s robustness, several test cases and special concerns, including multiple node upsets (MNU) and half-select, are examined.

Operation Modes Analysis and Limitation for Diode-Assisted Buck–Boost Voltage Source Inverter With Small Voltage Vector

Diode-assisted buck-boost voltage source inverter (VSI) boosts the dc source voltage by introducing diode-assisted capacitor network. With parallel capacitive charging and series capacitive discharging, the new topology extends voltage regulation range and avoids extreme duty ratio of switching devices in the front boost circuit. As for the unique structure, various novel pulse-width modulation strategies are provided to obtain the linear voltage gain with regard to the chopped intermediate dc-link voltage of the inverter bridge in one switching time period. It provides a competitive solution for high voltage gain applications. However, when the inverter supplies inductive or capacitive load with extreme low load power factor, the unidirectional current flow of the diode may limit the application of the converter utilizing small voltage vectors for ac output voltage extension. As a result, diode-assisted buck-boost VSI exhibits new operation mode that has not been discussed before. This paper makes a detailed circuit analysis of the relationship between the undesired operation condition and load power factor. Then, a simple approach to totally eliminate the undesired limitation by replacing the diodes with controlled switching devices is provided. Finally, the related simulations and experiments are implemented to verify all the theoretical findings and solutions.