Low power consumption 4-channel variable optical attenuator array based on planar lightwave circuit technique

The power consumption of a variable optical attenuator（VOA） array based on a silica planar lightwave circuit was investigated. The thermal field profile of the device was optimized using the finite-element analysis. The simulation results showed that the power consumption reduces as the depth of the heat-insulating grooves is deeper, the up-cladding is thinner,the down-cladding is thicker, and the width of the cladding ridge is narrower. The materials component and thickness of the electrodes were also optimized to guarantee the driving voltage under 5 V. The power consumption was successfully reduced to as low as 155 mW at an attenuation of 30 dB in the experiment.

Study of a GaAs MESFET Model with Ultra-Low Power Consumption

A model of enhancement mode GaAs MESFET (EFET) for low power consumption and low noise applications has been obtained by using a small signal equivalent circuit whose component values are derived from the physical parameters and the bias condition. The dependence of the RF performance and DC power consumption on physical, material and technological parameters of EFET is also studied. The optimum range of the physical parameters is given which is useful for the design of active device of ultra low power consumption MMIC.

Low-noise,low-power-consumption seafloor vector magnetometer

The seafloor vector magnetometer is an effective tool for marine geomagnetic surveys and seafloor magnetotelluric(MT)detection.However,the noise,power consumption,cost,and volume characteristics of existing seafloor vector magnetometers are insufficient for practical use.Therefore,a low-noise,low-power-consumption seafloor vector magnetometer that can be used for data acquisition of deep-ocean geomagnetic vector components is developed and presented.A seafloor vector magnetometer mainly consists of a fluxgate sensor,data acquisition module,acoustic release module,glass sphere,frame,burn-wire release,and anchor.A new low-noise data acquisition module and a fluxgate sensor greatly reduce power consumption.Furthermore,compact size is achieved by integrating an acoustic telemetry module and replacing the acoustic release with an external burn-wire release.The new design and magnetometer characteristics reduce the volume of the instrument and the cost of hardware considerably,thereby improving the integrity and deployment efficiency of the equipment.Theoretically,it can operate for 90 days underwater at a maximum depth of 6000 m.The seafloor vector magnetometer was tested in the South China Sea and the Philippine Sea and obtained high-quality geomagnetic data.The deep-water environment facilitates magnetic field data measurements,and the magnetometer has an approximate noise level of 10 pT/rt(Hz)@1 Hz,a peak-to-peak value error of 0.2 nT,and approximate power consumption of 200 mW.The fluxgate sensor can measure the magnetic field in the lower frequency band and realize geomagnetic field measurements over prolonged periods.

A Study of Efficient Power Consumption Wireless Communication Techniques/ Modules for Internet of Things (IoT) Applications

A study of wireless technologies for IoT applications in terms of power consumption has been presented in this paper. The study focuses on the importance of using low power wireless techniques and modules in IoT applications by introducing a comparative between different low power wireless communication techniques such as ZigBee, Low Power Wi-Fi, 6LowPAN, LPWA and their modules to conserve power and longing the life for the IoT network sensors. The approach of the study is in term of protocol used and the particular module that achieve that protocol. The candidate protocols are classified according to the range of connectivity between sensor nodes. For short ranges connectivity the candidate protocols are ZigBee, 6LoWPAN and low power Wi-Fi. For long connectivity the candidate is LoRaWAN protocol. The results of the study demonstrate that the choice of module for each protocol plays a vital role in battery life due to the difference of power consumption for each module/protocol. So, the evaluation of protocols with each other depends on the module used.

A low power low noise analog front end for portable healthcare system

The presented analog front end （AFE） used to process human bio-signals consists of chopping in- strument amplifier （IA）, chopping spikes filter and programmable gain and bandwidth amplifier. The capacitor- coupling input of AFE can reject the DC electrode offset. The power consumption of current-feedback based IA is reduced by adopting capacitor divider in the input and feedback network. Besides, IA＇s input thermal noise is decreased by utilizing complementary CMOS input pairs which can offer higher transconductance. Fabricated in Global Foundry 0.35 μm CMOS technology, the chip consumes 3.96 μA from 3.3 V supply. The measured input noise is 0.85μVrms （0.5-100 Hz） and the achieved noise efficient factor is 6.48.

A low power cyclic ADC design for a wireless monitoring system for orthopedic implants

This paper presents a low power cyclic analog-to-digital convertor （ADC） design for a wireless monitoring system for orthopedic implants. A two-stage cyclic structure including a single to differential converter, two multiplying DAC functional blocks （MDACs） and some comparators is adopted, which brings moderate speed and moderate resolution with low power consumption. The MDAC is implemented with the common switched capacitor method. The 1.5-bit stage greatly simplifies the design of the comparator. The operational amplifier is carefully op- timized both in schematic and layout for low power and offset. The prototype chip has been fabricated in a United Microelectronics Corporation （UMC） 0.18-μm 1P6M CMOS process. The core of the ADC occupies only 0.12 mm2. With a 304.7-Hz input and 4-kHz sampling rate, the measured peak SNDR and SFDR are 47.1 dB and 57.8 dBc respectively and its DNL and INL are 0.27 LSB and 0.3 LSB, respectively. The power consumption of the ADC is only 12.5 μW in normal working mode and less than 150 nW in sleep mode.

One-step solvothermal synthesis of indium oxide as liquefied petroleum gas sensor

A liquefied petroleum gas （LPG） sensor with high selectivity, sensitivity and low power consumption has been developed based on indium oxide with very low resistance. Nanocrystalline In203 gas sensing materials were directly synthesized through a one-step controllable solvothermal process at 210 ℃ for 24 h, using InCI3.4H2O as the starting material, cetyltrimethyl ammonium bromide （CTAB） as additive and ethanol as the solvent. The obtained samples were characterized by X-ray diffraction （XRD）, and transmission electron microscopy （TEM）. The results showed that indium oxide takes on uniform cubic shape with range size of 10~30 nm and fine dispersivity. Gas sensitivity was measured in a mixing static gas. The results indicated that 3.0 V is the best working voltage of the sensor to LPG. Sensitivity is 12.6. The response-time and recovery-time are 3 s and 10 s respectively. Power consumption is only around 200 mW.

An Improved Wireless Sensor Network Routing Algorithm

High performance with low power consumption is an essential factor in wireless sensor networks （WSN）. In order to address the issue on the lifetime and the consumption of nodes in WSNs, an improved ad hoc on-demand distance vector routing （IAODV） algorithm is proposed based on AODV and LAR protocols. This algorithm is a modified on-demand routing algorithm that limits data forwarding in the searching domain, and then chooses the route on basis of hop count and power consumption. The simulation results show that the algorithm can effectively reduce power consumption as well as prolong the network lifetime.

Design of transit-time difference ultrasonic heat meter based on TDC-GP21

According to the transit-time difference measurement method,we proposed a design scheme of ultrasonic heat meter based on TDC-GP21.The measurement unit TDC-GP21 mainly completes transit-time measurement and inlet,outlet temperature measurement functions.Control unit and data processing unit based on MSP430F4152 of TI corporation complete functions including peripherals control,data analysis,temperature compensation algorithm,flow pattern compensation algorithm and low power consumption control.The design meets the Town Construction Professional Standard CJ 128-2007,and furthermore,some performances can be improved.

An Overview of the Miniaturization and Endurance for Wearable Devices

The miniaturization and endurance of wearable devices have been the research direction for a long time.With the development of nanotechnology and the emergence of microelectronics products,people have explored many new strategies that may be applied to wearable devices.In this overview,we will summarize the recent research of wearable devices in these two directions,and summarize some available related technologies.

Indium-organic framework CPP-3(In)derived Ag/In_(2)O_(3) porous hexagonal tubes for H_(2)S detection at low temperature

There is a great demand for high-performance hydrogen sulfide(H_(2)S)sensors with low operating temperatures.Ag/In_(2)O_(3)hexagonal tubes with different proportions were prepared by the calcination of Ag+-impregnated indium-organic frameworks(CPP-3(In)),and the developed sensors exhibit enhanced gas-sensing performance toward H_(2)S.Gas sensing measurements indicate that the response of Ag/In_(2)O_(3)(2.5 wt%)sensor to 5 ppm H_(2)S has the highest response(119),operated at 70℃.The Ag/In_(2)O_(3)(2.5 wt%)based sensor exhibits short response time(20 s),low detection limit(300 ppb),and good selectivity toward H_(2)S gas,which imply that the CPP-3(In)-derived Ag/In_(2)O_(3)hexagonal tube is a promising candidate to be constructed a low power-consumption H_(2)S sensor.

Serrated periodic electrode for high energy efficiency and large bandwidth acousto-optic modulators

In an acousto-optic modulator,the electrode shape plays an important role in performance,since it affects the distribution of the acoustic field.The acousto-optic modulator based on the conventional rectangular electrode has the problems of low energy efficiency and small modulation bandwidth due to an imperfect acoustic field.In this paper,a new serrated periodic electrode has been proposed for using acousto-optic modulator transducers.The proposed electrode has the following advantages.By using serrated periodic electrodes to suppress the sidelobes,the collimation of the acoustic field in the direction perpendicular to the light incidence is improved.This makes the acousto-optic modulator have a stable diffraction efficiency fluctuation and high energy efficiency.In addition,the electrode has a large divergence angle in the direction of light incidence,so a large bandwidth can be obtained.The simulations and experiments demonstrate that the serrated periodic electrode has an increased bandwidth and high energy efficiency.

A linear stepping PGA used in CMOS image sensors

A low power linear stepping digital programming gain amplifier （PGA） is designed for CMOS image sensors. The PGA consists of three stages with gain range from one to nine, The gain is divided into four regions and each range has 128 linear steps. Power consumption of the PGA is saved by good tradeoff between variation of amplifier feedback coefficient, pipeline stages and gain regions. With thermometer-binary mixed coding and linear pipeline gain stepping, the load capacitance keeps constant when the gain of one stage is changed. The PGA is designed in the SMIC 0.18 μm process. Simulation results show that the power consumption is 3.2 mW with 10 bit resolution and 10 MSPS sampling rate. The PGA has been embedded in a 0.3 megapixel CMOS image sensors and fabricated successfully.

Capping CsPbBr3 with ZnO to improve performance and stability of perovskite memristors

The rapid development of information technology has led to an urgent need for devices with fast information storage and processing, a high density, and low energy consumption. Memristors are considered to be next-generation memory devices with all of the aforementioned advantages. Recently, organometallic halide perovskites were reported to be promising active materials for memristors, although they have poor stability and mediocre performance. Herein, we report for the first time the fabrication of stable and high-performance memristors based on inorganic halide perovskite （CsPbBr3, CPB）. The devices have electric field-induced bipolar resistive switching （ReS） and memory behaviors with a large on/off ratio （〉105）, low working voltage （〈1 V） and energy consumption, long data retention （〉104 s）, and high environmental stability, which are achieved via ZnO capping within the devices. Such a design can be adapted to various devices. Additionally, the heterojunction between the CPB and ZnO endows the devices with a light-induced ReS effect of more than 103 with a rapid response speed （〈1 ms）, which enables us to tune the resistance state by changing the light and electric field simultaneously. Such multifunctional devices achieved by the combination of information storage and processing abilities have potential applications for future computing that transcends traditional architectures.

Graphene-based all-optical modulators

All-optical devices,which are utilized to process optical signals without electro-optical conversion,play an essential role in the next generation ultrafast,ultralow power-consumption optical information processing systems.To satisfy the performance requirement,nonlinear optical materials that are associated with fast response,high nonlinearity,broad wavelength operation,low optical loss,low fabrication cost,and integration compatibility with optical components are required.Graphene is a promising candidate,particularly considering its electrically or optically tunable optical properties,ultrafast large nonlinearity,and high integration compatibility with various nanostructures.Thus far,three all-optical modulation systems utilize graphene,namely free-space modulators,fiber-based modulators,and on-chip modulators.This paper aims to provide a broad view of state-of-the-art researches on the graphene-based all-optical modulation systems.The performances of different devices are reviewed and compared to present a comprehensive analysis and perspective of graphene-based all-optical modulation devices.

DSOI—a novel structure enabling adjust circuit dynamically

A double silicon on insulator（DSOI） structure was introduced based on fully depleted SOI（FDSOI）technology.The circuit performance could be adjusted dynamically through the separate back gate electrodes applied to N-channel and P-channel devices.Based on DSOI ring oscillator（OSC）,this paper focused on the theoretical analysis and electrical test of how the OSC＇s frequency being influenced by the back gate electrodes（soi2n,soi2p）.The testing results showed that the frequency and power consumption of OSC could change nearly linearly along with the back gate bias.According to the different requirements of the circuit designers,the circuit performance could be improved by positive soi2 n and negative soi2 p,and the power consumption could be reduced by negative soi2n and positive soi2p.The best compromise between performance and power consumption of the circuit could be achieved by appropriate back gate biasing.