Interface Circuit Research Articles

Perspectives in flow-induced vibration energy harvesting

Flow-induced vibration (FIV) energy harvesting has attracted extensive research interest in the past two decades. Remarkable research achievements and contributions from different aspects are briefly overviewed. Example applications of FIV energy harvesting techniques in the development of Internet of Things are mentioned. The challenges and difficulties in this field are summarized from two sides. First, the multi-physics coupling problem in FIV energy harvesting still cannot be well handled. There is a lack of system-level theoretical modeling that can accurately account for fluid–structure interaction, the electromechanical coupling, and complicated interface circuits. Second, the robustness of FIV energy harvesters needs to be further improved to adapt to the uncertainties in practical scenarios. To be more specific, the cut-in wind speed is expected to be further reduced and the power output to be increased. Finally, Perspectives on the future development in this direction are discussed. Machine-learning approaches, the versatility of metamaterials, and more advanced interface circuits should receive more attention from researchers, since these cutting-edge techniques may have the potential to address the multi-physics modeling problem of FIV energy harvesters and significantly improve the operation performance. In addition, in-depth collaborations between researchers from different disciplines are anticipated to promote the FIV energy harvesting technology to step out of the lab and into real applications.

Considerations for Neuromorphic Supercomputing in Semiconducting and Superconducting Optoelectronic Hardware.

Any large-scale spiking neuromorphic system striving for complexity at the level of the human brain and beyond will need to be co-optimized for communication and computation. Such reasoning leads to the proposal for optoelectronic neuromorphic platforms that leverage the complementary properties of optics and electronics. Starting from the conjecture that future large-scale neuromorphic systems will utilize integrated photonics and fiber optics for communication in conjunction with analog electronics for computation, we consider two possible paths toward achieving this vision. The first is a semiconductor platform based on analog CMOS circuits and waveguide-integrated photodiodes. The second is a superconducting approach that utilizes Josephson junctions and waveguide-integrated superconducting single-photon detectors. We discuss available devices, assess scaling potential, and provide a list of key metrics and demonstrations for each platform. Both platforms hold potential, but their development will diverge in important respects. Semiconductor systems benefit from a robust fabrication ecosystem and can build on extensive progress made in purely electronic neuromorphic computing but will require III-V light source integration with electronics at an unprecedented scale, further advances in ultra-low capacitance photodiodes, and success from emerging memory technologies. Superconducting systems place near theoretically minimum burdens on light sources (a tremendous boon to one of the most speculative aspects of either platform) and provide new opportunities for integrated, high-endurance synaptic memory. However, superconducting optoelectronic systems will also contend with interfacing low-voltage electronic circuits to semiconductor light sources, the serial biasing of superconducting devices on an unprecedented scale, a less mature fabrication ecosystem, and cryogenic infrastructure.

Supplementary control based on current source coupling for improving dynamic characteristics of active distribution network

Supplementary control (SC) technology is widely leveraged by power supply companies in active distribution networks (ADNs) to improve their stability and dynamic characteristics. Yet, the existed SCs are generally implemented from inside the converter controllers of distributed generators (DGs) or active loads, so there is a need to redesign the internal physical structure of the existing controller, resulting in the increasing work amount of assembling and workability. This paper studies the specific R & D process of a novel external coupling type SC (ECSC), which is based upon current source injection (CSI-ECSC) for improving the dynamic characteristics of ADN. The SC current signals are coupled to the current sampling loop from outside the converter controller. And the employment of the existing current sample makes it unnecessary to redesign the internal physical structure of the existing controller. As a result, the SC assembling is simplified and its workability is improved. In this paper, a detailed exemplary ADN with direct-drive permanent magnet synchronous generator (PMSG) is firstly set up in math for full eigenvalue analysis. Then, the CSI-ECSC is designed with its control loop, interface circuit, and parameter setting. Furthermore, by using PSCAD/EMTDC, groups of case studies are conducted in ADNs where photovoltaics (PVs) and energy storage (ES) are included. Finally, the real-time hardware-in-the-loop (HIL) testing validates the functionality of the realized CSI-ECSC in RTDS.

Broadband piezoelectric energy harvesting induced by mixed resonant modes under magnetic plucking

A piezoelectric device connected to the standard interface circuit is proposed for harvesting energy by inducing the mixed resonant modes of vibration under the two-point rotary magnetic plucking. It consists of a piezoelectric cantilever beam attached to a tip magnet and a second magnet placed on the middle of the beam. Both magnets are excited by another two magnets aligned radically and attached to a rotating host. The two impulsive forces from these magnets are made in opposite directions for the ease of inducing the second resonant mode. As a result, the harvester device exhibits the pronounced broadband energy harvesting which can not be achieved by the conventional design based on the one-point magnetic plucking for exciting a single resonant mode. The analysis is based on the Fourier decomposition of magnetic impulsive forces for realizing the phenomenon of frequency up-conversion. In addition, the estimate of harvested power is analytically derived based on using the equivalent load impedance which is originally proposed for analyzing harvester arrays. The result shows that the theoretical prediction agrees well with the experimental observation. Further, the rotary frequency response exhibits the remarkable feature of broadband energy harvesting as the output power is increased up to 2500% higher than that in the off-resonance region of the setup allowing plucking only on the tip magnet.

Synchronized switch piezoelectric energy harvesting using rotating magnetic ball and reed switches

Synchronized switch harvesting on inductor (SSHI) interface circuit has been developed to boost the harvesting capability of piezoelectric energy harvesters (PEHs). Although some electronic self-powered peak-detector and switching circuits have been proposed to support the practical realization of SSHI, the energy dissipation and voltage drops in transistors and diodes of the self-powered circuits might significantly deteriorate the actual energy harvesting performance. Some mechatronic designs were proposed as well. However, most of their switches are activated by touch impacts, which might introduce undesired high-order vibrations to the main structure. In this paper, rather than using the impact-engaged strategy discussed in the literature, a new mechanism using a magnetic ball for vibration synchronization and reed switches for switching operation is proposed. A PEH shunted to an SSHI interface circuit using the proposed mechatronic approach has been prototyped. Since the peak-detection and switching operations are completed by a mechanical mechanism, less passive electrical components, which consume extra energy, are required in our proposed design. Therefore, the overall energy harvesting performance is improved. Numerical simulations and experimental tests have validated the feasibility of the proposed design. The experimental results have shown that the power output produced by the proposed mechatronic self-powered SSHI design can be increased by and , as compared with the cases using a benchmark standard energy harvesting bridge rectifier and an electronic self-powered SSHI solutions, respectively. Moreover, owing to the new mechatronic design, the auxiliary mechanical components are embedded in the tip block of the cantilevered PEH, rendering the whole system to be a compact design.

A real-time ultra-low light color imaging system based on FPGA

This article shows a low light color image acquisition system, The core components of the system are the Fairchild’s SCMOS image sensor CIS1910F1111 and XILINX’s Artix-7 XC7A100T-2CSG324I FPGA, the remarkable advantage of the system is that it can obtain better color imaging effect under lower illumination environment, and the image noise is much less than other similar products. Based on the excellent imaging performance of the image detector, a high performance real-time low-light level color imaging system is developed. This imaging system can obtain the characteristic information of the targets under ultra-low illuminance environment, including the details, colors and so on. The hardware of the low light level imaging system mainly contains a color SCMOS image sensor and a FPGA, a driving circuit of a combination of DDR3, the ultra-low noise power conversion circuit and a Camera-Link and a 3G-SDI interface circuits. The SCMOS chip is used for photoelectric conversion of the shot scene and the FPGA is used for the control of the whole imaging system, image acquisition and image processing, etc, The FPGA software system consists of SCMOS initialize configuration and timing control module, automatic exposure control module, real-time color image processing module, imaging tone mapping module, image denoising module and image enhancement module. The automatic exposure control (AEC) module adaptively adjusts the average gray value of the region of interest. The module automatically calculates the exposure time and gain value of the next frame according to the current frame image data value. The real-time color image processing module includes color restoration, automatic white balance and color spaces conversion, etc. The image denoising module uses the advanced real-time guide-filter algorithm. The image tone mapping module and enhancement module are proposed based on an improved automatic threshold logarithmic and enhancement algorithm. Combining the hardware and FPGA soft algorithm with excellent performance, the imaging results show that the system can get good color image effect of the ultra-low light level about 10-2lx.

Lumped Parameter Evaluation Model Analysis and Load Coupling Modeling of Piezoelectric Composite Cantilever Beam

In order to study the working mechanism of piezoelectric composite cantilever beam and improve the ability of predicting the power generation performance of piezoelectric composite cantilever vibration energy harvester (CVEH), the simple and high-precision analysis models of equivalent mass and equivalent stiffness of CVEH are proposed. The natural frequency method is used to compare the calculation results of the evaluation model, Rayleigh Ritz method and finite element simulation, and the results show that the consistency (Ω) between the evaluation model and the finite element simulation is more than 95%. The influence of the mass ratio (α) between the end mass of the beam and the weight of the beam itself on Ω is analyzed by using the proposed evaluation model, which shows that Ω increases with the increase of α, and the increase is more significant in the range of 0<α<4. The analysis of the influence of α on the natural frequency of the beam () shows that decreases with the increase of α, and the decrease is more obvious in the range of 0<α<2. According to the evaluation model, the electromechanical conversion analysis models of CVEH and its control equation with coupling of standard energy harvesting (SEH) interface circuit and Double synchronous switch harvesting (DSSH) interface circuit are established respectively, and the mathematical models of its output voltage are derived. The power generation experiment of CVEH is carried out, and the results show that the proposed models are in good agreement with the experimental results.

A 0.4 V, 19 pW subthreshold voltage reference generator using separate line sensitivity and temperature coefficient correction stages

Sensor nodes and IoT systems require blocks that not only consume low power but also have good accuracy. Voltage reference generators are also considered important building blocks in sensor interface circuits. This paper presents a solution to increase the accuracy of low power subthreshold voltage generators by lowering the circuit sensitivity to temperature and supply voltage variations. The enhancement is achieved by using two separate stages for temperature coefficient (TC) and line sensitivity (LS) correction. A 0.18 µm standard CMOS process has been used for the proposed structure. The effects of parameter variations in the fabrication process are investigated using post-layout simulation and Monte Carlo analysis. In the supply voltage of 0.4–2 V, an LS of 143.8 ppm/V is obtained. In typical corner conditions, the achieved TC is 7.45 ppm/°C over the temperature range of 0–80 °C. Due to process changes, and mainly affected by threshold voltage variations, the average TC can change to 39.2 ppm/°C. The minimum power consumption at 0 °C and at a supply voltage of 0.4 V is 3.25 pW while the power consumption increases to 2.84 nW in 80 °C and at the maximum supply voltage of 2 V.

A Novel Conditioning Circuit for Floating-Gate ISFET Bio-Sensor

Floating-Gate-Ions-Sensitive-Field-Effect-Transistors (FG-ISFETs) are becoming the sensor’s platform for various fields such as biomedical and chemical sensors. Despite many advantages like quick response, small size as well as wide measurement range, the efficiency of the output measurement is widely affected by temperature, This requires more safety in the measured results and the analysis’s tools. This study describes a novel integrated circuit that improves the thermal stability of the output signal of the ion-sensitive field effect transistors (ISFETs). After that, we investigate the temperature dependency of the FG-ISFET using the mentioned macro model and we shows that the temperature coefficient is about of 6 mV/°C. Afterward, a new integrated interface circuit that can perform great temperature compensation was developed. This operation aims to enhance stability of readout circuit for FG-ISFET. The achieved result of the FG-ISFET under different simulations shows that the readout circuit has a good temperature compensation i.e. :2.4 〖10〗^(-9) mV/°C.

A unified equivalent circuit and impedance analysis method for galloping piezoelectric energy harvesters

In the past decade, galloping-based energy harvesters (GPEH) connected with various interface circuits have been developed and analytical models have been built. However, the power performances of these advanced structures and circuits are always treated separately, and a general model is missing to gain insights at a system level. To tackle this issue, this paper proposes a unified analysis framework for GPEHs. Its results are consistent with validated (but disconnected) results in the literature. The method provides an integrated view of the physics of linear GPEHs in multiple domains at the system level, and elucidates the similarities and differences among power behaviors of GPEHs connected with various interface circuits. The framework is based on two major elements: an equivalent circuit that represents the entire system, and an equivalent impedance that represents the interface circuit. Firstly, the electromechanical system is linearized and modeled in the electrical domain by an equivalent self-excited circuit with a negative resistive element representing the external aerodynamic excitation, and a general load impedance representing the interface circuit. Then, a closed-form, analytical expression of the harvested power is obtained based on the Kirchhoff’s Voltage Law, from which the optimal load, maximum power, power limit, and critical electromechanical coupling (minimum coupling to reach the power limit) are determined. In this unified analysis, the exact type of energy harvesting interface circuit is not assumed. After that, the power characteristics of a GPEH connected with five representative interface circuits are analytically derived and discussed, by using the particular equivalent impedance of the interface circuit of interest. It is shown that they are subjected to the same power limit. However, the critical electromechanical coupling depends on the type of circuit. Throughout the discussions, impedance plots are used to illustrate the relationship between the internal system characteristics and external load impedance, facilitating the understanding of system power behavior.

Ultrathin Solar Cells Based on Atomic Layer Deposition of Cubic versus Orthorhombic Tin Monosulfide

Tin monosulfide can be grown in cubic (π-SnS) and orthorhombic (α-SnS) polymorphs by low-temperature atomic layer deposition (ALD). The optical properties of these polymorphs make them attractive for the realization of plasmonic solar cells with ultrathin absorber layers down to 10 nm in thickness. SnS is also an earth-abundant and nontoxic compound semiconductor of high interest for regular thin-film photovoltaics. To better understand the behavior of the two SnS polymorphs in ultrathin solar cell configurations, we here fabricate, characterize, and analyze a range of such devices. ALD is used to grow SnS and form heterojunctions with zinc oxysulfide [Zn(O,S)], acting as a buffer layer with a composition-tunable bandgap. Apart from the roles of the SnS polymorph and Zn(O,S) composition, the effects of the back contact material and thicknesses of buffer and absorber layers are investigated. Devices using π-SnS and pure ZnO buffers yield the highest photocurrents (3.1 mA/cm2) and higher open circuit voltage (159 mV) than similar α-SnS-based devices. Analysis of the equivalent-circuit parameters suggests that interface recombination limits the voltage for these devices. While Zn(O,S) with a higher sulfur content provides chemical passivation of the SnS interface and excessive open circuit voltages above 600 mV, it also exhibits a too high conduction band offset, which hampers current collection. A growth delay during the ALD of Zn(O,S) on SnS initially amplifies the known sulfur–oxygen exchange reaction, such that a sulfur-rich Zn(O,S) region forms next to the SnS interface. This causes a thin ZnS-like barrier to form already for low cycle fractions of the H2S precursor in the ALD super-cycle. Voltage and fill factor trends suggest an optimal SnS absorber layer thickness in the range of 15–35 nm, presenting an opportunity for plasmonic absorption enhancement. Devices with π-SnS show most promise, but interface recombination versus current-blocking is a dilemma for the SnS/Zn(O,S) heterojunction.

P‐16.3: A Tactile Sensor Interface Formed by Two TFTs and One Capacitor to Enable Dynamic and Static Force Sensing

In this article, we propose an interface circuit formed by thin film transistor(TFT) for tactile sensing applications. This interface circuit is composed of two TFTs and a capacitor, in connection with a polyvinylidenefluoride (PVDF) transducer for force sensing. An analytical model is presented to explain the working principle of the interface circuit, and an experimental study of a 10×10 tactile sensing array is built to evaluate the feasibility of the circuit. Our study shows such interface circuit is promising to obtain the dynamic and static force sensing.

A Dual-Mode Multifunctional Pulsed Radio-Frequency Stimulator for Trigeminal Neuralgia Relief and its Animal Model.

This work proposed a programmable pulsed radio-frequency (PRF) stimulator for trigeminal neuralgia (TN) relief on demand. The implantable stimulator is a miniaturized micro-system which integrates a wireless interface circuit, a sensor interface circuit, a PRF pattern generation circuit and a logic controller. The multifunctional stimulator capable of delivering current/voltage stimulation provides the choice of the biphasic sinusoidal, square and patterned waveform for PRF treatment researches. The external handheld device can wirelessly transmit the parameters of frequency, amplitude, pulse duration and repetition rate of the pulse train to the implanted stimulator. While stimulating, the temperature sensor can monitor the operating temperature. The feedback signal is transmitted in medical implanted communication system (MICS). The micro-system is fabricated in a 0.35 μm CMOS process with a chip size of 3.1 × 2.7 mm2. The fabricated chip was mounted on a 2.6 × 2.1 cm2 test board for studying the in vivo efficacy of pain relief by PRF. Animal studies of PRF stimulation and commonly-used medication for trigeminal neuralgia are also demonstrated and the presented results prove that PRF stimulation has greater effectiveness on trigeminal neuralgia relief comparing to the medication. The effectiveness period lasts at least 14 days. The results of neural recording show that the PRF stimulation of trigeminal ganglion (TG) attenuated neuron activities without being severely damaged. Pathology also revealed no lesion found on the stimulated area.

Data transmission system of networked digital voice room based on Internet of Things technology

In order to solve the problem of poor transmission performance caused by data congestion in network digital language lab, its data transmission system is designed based on the technology of internet of things. In the hardware part, the main control circuit and transmission interface circuit are designed to reduce the signal reflection caused by the change of line width and angle. In the software part, the data transmission compression algorithm is designed to reduce the communication overhead. The internet of things technology is used to set data transmission nodes, and the weighted fairness data transmission protocol is set to control the energy efficiency of transmission. The random key pre-distribution scheme based on the hash key chain is used to construct the data security transmission model. The experimental results show that, compared with the data transmission system based on data mining and cloud computing, the designed system achieves the lowest word error rate and sentence error rate, and has better data transmission performance.

Demonstration of Interface Circuits Between Half- and Single- Flux- Quantum Circuits

We demonstrated interface circuits between a half-flux-quantum (HFQ) circuit and a rapid single-flux-quantum (RSFQ) circuit to obtain SFQ/HFQ and HFQ/SFQ converters. These converters were created by simply inserting a resistor between an RSFQ circuit and the adjacent HFQ circuit, where both circuits are based on pulse logic. These converters enable us to create combinatory circuits that make the best use of the features of the two circuits. Using a DC/SFQ, SFQ/HFQ, HFQ/SFQ, and SFQ/DC converter, we measure an HFQ Josephson transmission line (JTL) composed of eight 0-0-π superconducting quantum interference devices (SQUIDs), which are the essential elements of an HFQ circuit. The 0-0-π SQUIDs are composed of two conventional Josephson junctions and a π-shifted ferromagnetic junction. The HFQ JTL demonstrated in this study is driven by a bias current 11-fold lower than that of a similar RSFQ JTL. These experimental results indicate that the HFQ circuit requires power that is two or more orders of magnitude lower than that of an RSFQ circuit.

OTN Technology Development and Application in Metropolitan Electronic Power Network

Based on the relevant meaning, advantages and characteristics of the OTN technology, the OTN equipment can be applied in man, including the application in the convergence layer, in building circuit scheduling and CPRI interface circuit loading of the access layer. As a transmission network technology in the metropolitan electronic power, the OTN has a broad prospect in development and application in the future.

Nonlinear dynamic analysis of a reciprocative magnetic coupling on performance of piezoelectric energy harvester interfaced with DC circuit

In this article, a nonlinear piezoelectric harvester coupled with a standard rectifying circuit is developed. Contrary to traditional Duffing-type magnetic harvester mechanism, the nonlinear effect in the system is induced by a dynamic tipmass with embedded magnet. Further, dynamic equation of the system is derived and subsequently, its equivalent circuit model is devised to evaluate its performance with a conventional harvester. Simulation and experimental results exhibit that the nonlinear effect due to the force coupling has a profound effect on peak output power and operational bandwidth of the harvester as compared to linear system with DC interface circuit.

Preliminary observations of a system for determination of phototherapy exposure over a neonate body shape

While it is possible to determine the irradiance and spectral content for a given neonatal phototherapy device at various locations over a neonate's surface, this does not allow estimation of the total rate of energy delivery within a specific spectral range over the neonate's exposed body surface. A series of 192 blue wavelength enhanced silicon photodiodes was distributed over the surface of a commercially available newborn body shape and connected to a specially designed interface circuit. Placement of photosensors over the surface of the baby shape was determined with consideration of the surface area of twelve specific anatomical areas where each was allocated 16 individual photodiodes. Calibration of detection channels for specific wavelength intervals was undertaken using a Bentham dmc150 spectroradiometer system and also a separate hand held spectroradiometer. This made it possible to estimate the effective integrated dose rate in Watts for specific wavelength intervals such as 460 nm to 490 nm as identified by the American Academy of Pediatrics for phototherapy lamp devices. This allowed identification of dose rate contributions from specific anatomical areas. Initial observations are reported for a range of phototherapy lamp systems and the findings are discussed in terms of their predicted relative clinical effectiveness. Options are also discussed in relation to the future development of the reported measurement system.

KINEMATICS ANALYSIS AND IMPLEMENTATION OF THREE DEGREES OF FREEDOM ROBOTIC ARM BY USING MATLAB

The kinematics modeling of the robot arm plays an important role in robot control. This paper presents the kinematic model of a three-degree of freedom articulated robot arm, which is designed for picking and placing an application with hand gripper, where a robot has been manufactured for that purpose. The forward kinematic model has been presented in order to determine the end effector’s poses using the Denavit-Hartenberg (DH) convention. For inverse kinematics, an algebraic solution based on trigonometric formulas mixed with geometric method was adopted for a 3 DOF modular manipulator taking into account the existence of a shoulder offset. MATLAB software was used as a tool to simulate and implement the motional characteristics of the robot arm, by creating a 3D visual software package under designing a Graphical User Interface "GUI" with a support simulation from robotic Toolbox (Rtb 10.3). Finally, an electronic interfacing circuit between the GUI program and the robot arm was developed using Arduino microcontroller to control the robot motion. The presented work can be applicable for learning the reality interface design methodology of the other kinds of robot manipulators and achieve a suitable solution for the motional characteristics

Complex event detection for commodity distribution Internet of Things model incorporating radio frequency identification and Wireless Sensor Network

This paper discusses the key technologies for the fusion of Radio Frequency Identification (RFID) technology and wireless sensor networks through a fusion approach; meanwhile, it addresses the problem of energy imbalance infusion networks. This paper introduces the network energy consumption calculation methods under direct transmission and minimum energy multi-hop routing protocols, and designs an improved network structure model to improve the communication scale. The RFID reading and writing system based on Zig Bee technology is developed, and focuses on the hardware interface circuit design of the fusion system, the development of compatible communication protocols, the anti-collision algorithm, and the transmission performance of the system under two outdoor environments. The design of the environmental collection terminal uses relevant sensors to collect the transport environment data in the carriage. And Wireless Sensor Network (WSN) combined with General Packet Radio Service (GPRS) technology realizes the function of the main aggregation node of wireless sensors. The method achieves data aggregation and data transmission, and the development of the application platform of the monitoring system uses software technology. Based on the browser/server (B/S) architecture, the development of the monitoring system is finally realized. Finally, the cold chain transportation simulation experiment was conducted to test the system, and the results showed that the hardware of the cold chain coordination monitoring system can work normally and the software design of the monitoring system can meet the basic requirements of the system for the third-party logistics enterprises. The efficiency of our results is improved by about 10% compared to other studies, and their accuracy is improved to a higher degree, which makes our model more practical.