Test Circuit Research Articles

DESIGN, CONSTRUCTION AND TESTING OF CELLPHONE DETECTOR

A cell phone detector is a device specifically designed to detect and locate the presence of a cell phone in a specific area. Cell phone detection has been studied for a long time. Techniques have been developed or proposed on how to detect cell phones. Most of them are trying to exploit features such as audio systems, RF systems, and common materials in phones and study how these can be used as the basis for cell phone detection. This study uses the cell phone's RF system as a function to detect the presence of a cell phone. Using relatively inexpensive and available electronic components, a circuit that detects signals in the 0.9 GHz to 3 GHz range is used to detect a mobile phone in use. The constructed cell phone detector can detect the presence of various activated cell phones within 1.5 meters around it and indicate this by flashing a light emitting diode (LED) connected to its output. Even if the cell phone is in silent mode. The circuit test results show that the cell phone detector works well.

Efficient Zero-Sequence Impedance Measurement in Autotransformers Using Low-Voltage Excitation

In accordance with the IEEE standard, the zero-sequence impedance test of transformers necessitates an open or short circuit test on the high-voltage side winding. Power source excitation is applied to the high-voltage test winding using a high-capacity test power supply. To circumvent the need for a large-capacity, high-voltage test power supply in field tests, this paper proposes a method for measuring zero-sequence impedance in autotransformers based on low-voltage excitation and disconnection testing. By applying a three-phase power supply to the lowest voltage side of the autotransformer and creating a disconnection condition, an unbalanced test scenario is established. Subsequently, the composite sequence network equivalent circuit for one-phase and two-phase disconnections between the high-voltage side and the low-voltage side of the transformer is formulated. Calculation formulas for the zero-sequence impedance of the autotransformer under various conditions are derived. The accuracy of the zero-sequence impedance is verified using MATLAB/Simulink simulation software 2018b, evaluating double-winding and three-winding autotransformers in breaking tests under different connection modes. The error is found to be less than 3%. The results of this study affirm the high accuracy of the proposed method.

A Two-Dimensional Computer-Aided Design Study of Unclamped Inductive Switching in an Improved 4H-SiC VDMOSFET.

Due to its high thermal conductivity, high critical breakdown electric field, and high power, the silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) has been generally used in industry. In industrial applications, a common reliability problem in SiC MOSFET is avalanche failure. For applications in an avalanche environment, an improved, vertical, double-diffused MOSFET (VDMOSFET) device has been proposed. In this article, an unclamped inductive switching (UIS) test circuit has been built using the Mixed-Mode simulator in the TCAD simulation software, and the simulation results for UIS are introduced for a proposed SiC-power VDMOSFET by using Sentaurus TCAD simulation software. The simulation results imply that the improved VDMOSFET has realized a better UIS performance compared with the conventional VDMOSFET with a buffer layer (B-VDMOSFET) in the same conditions. Meanwhile, at room temperature, the modified VDMOSFET has a smaller on-resistance (Ron,sp) than B-VDMOSFET. This study can provide a reference for SiC VDMOSFET in scenarios which have high avalanche reliability requirements.

(Invited, Digital Presentation) 2-D Van Der Waal Materials for Advanced Interconnect Applications

Advanced interconnects require new materials to minimize high frequency signal loss and manage high temperature excursions due Joule heating. In this talk, we will review our on-going material selection modeling, and the thermo-mechanical reliability testing of interconnect prototypes that incorporate 2-D van der Waal thin films. Specifically, we will discuss our use of broadband microwave spectroscopy, that enables the accurate in-operando analysis of the electrical and magnetic properties without compromising the kinetic conditions of the experiment, to investigate high speed signal loss in 3-D integrated test circuits. The BDS method is sensitive to the actual electronic structure of the constituent materials and interfacial processes in the test structures. Using BDS, we have studied and characterized the 2-D van Der Wall, and other chalcogenide thin films in purposely built prototypical 3-D integrated circuit (3D-IC) during cycled high-temperature storage. We show that the microwave signal loss in these devices is attributable to the energy dissipation through the signal’s interactions with the copper barrier / cladding materials.

Retesting Schemes That Improve Test Quality and Yield Using a Test Guardband

The digital integrated circuit (IC) testing model module is applied in this study to simulate the fabrication and testing of integrated circuits. The yield and quality of ICs are analyzed by assuming that the wafer devices under test conditions are normal probability distributions. The difficulties of testing and verification become increasingly great as the design function of the chip becomes remarkably complex. Conversely, the automotive industry chip supply chain has been substantially affected since the COVID-19 outbreak. The shortage of chips in the auto-market has always existed; therefore, increasing available chips under a limited production capacity has become a top priority. Therefore, this study applies the digital integrated circuit testing model (DITM) and proposes a retest plan. This method does not require considerable time to collect large wafer data, nor does it require additional hardware equipment. Furthermore, the required test quality parameters are set, and the test is repeated on the device by adjusting the test guardband (TGB). Moreover, three retesting schemes are proposed to improve the IC test quality (Yq) and test yield (Yt) to meet the requirements of consumers for product quality. A set of 2021 IEEE International Roadmap for Devices and Systems (IRDS) parameters is used to demonstrate the three proposed retesting schemes. The simulation results from the 2021 IRDS data prove that the retest method can effectively improve the test yield (Yt). A comparison of the estimated results of the three retest methods shows that using the repeat test method can maximize the test yield without sacrificing the test quality (Yq). By contrast, repeat testing can indeed improve the test yield (Yt) by 14% or more. Moreover, the increase in sellable ICs not only increases additional earnings for corporations, but also alleviates the current global shortage of automotive ICs.

Integrated control strategy of semi-active suspension and in-wheel motors for handling limit of electric race car

An integrated control strategy is proposed to deal with extreme driving conditions for race cars using magnetorheological (MR) semi-active suspension and in-wheel motors. A novel controllable boundary is introduced as the vehicle state supervisor based on the phase portrait of yaw rate and side slip angle. Compared with the traditional stable region, it can better cope with the aggressive behaviors of racing drivers. The proposed integrated control algorithm consists of a controllable boundary-based hierarchy direct yaw moment controller (HDYC) and acceleration-based scheduling MR damper controller. The HDYC will generate the correct yaw moment based on the sliding mode method when vehicle states exceed the critical area of the controllable region. The MR damper controller includes vehicle attitude control (VAC) mode and maneuverability control (MC) mode. The switch of control mode is determined by vehicle states as well. According to the analysis of load transfer, the acceleration scheduling strategy based on the “g-g” ellipse is utilized to generate the desired current command. Three typical scenarios are conducted through co-simulation of Carsim and Simulink to verify the control strategy, including accelerating and hard braking test, double lane change test, and duration circuit test. Especially, the limit of actuators is taken into consideration. The simulation results show that the proposed integrated control strategy could reduce the lap time and increase the maneuverability as well as stability of race cars, compared with traditional direct yaw moment control. The ultimate acceleration of the vehicle is improved significantly.

Early Blood Clot Detection Using Forward Scattering Light Measurements Is Not Superior to Delta Pressure Measurements.

The occurrence of thrombus formation within an extracorporeal membrane oxygenator is a common complication during extracorporeal membrane oxygenation therapy and can rapidly result in a life-threatening situation due to arterial thromboembolism, causing stroke, pulmonary embolism, and limb ischemia in the patient. The standard clinical practice is to monitor the pressure at the inlet and outlet of oxygenators, indicating fulminant, obstructive clot formation indicated by an increasing pressure difference (ΔP). However, smaller blood clots at early stages are not detectable. Therefore, there is an unmet need for sensors that can detect blood clots at an early stage to minimize the associated thromboembolic risks for patients. This study aimed to evaluate if forward scattered light (FSL) measurements can be used for early blood clot detection and if it is superior to the current clinical gold standard (pressure measurements). A miniaturized in vitro test circuit, including a custom-made test chamber, was used. Heparinized human whole blood was circulated through the test circuit until clot formation occurred. Four LEDs and four photodiodes were placed along the sidewall of the test chamber in different positions for FSL measurements. The pressure monitor was connected to the inlet and the outlet to detect changes in ΔP across the test chamber. Despite several modifications in the LED positions on the test chamber, the FSL measurements could not reliably detect a blood clot within the in vitro test circuit, although the pressure measurements used as the current clinical gold standard detected fulminant clot formation in 11 independent experiments.

Development of new colloid osmotic pressure measurement method using ultrafiltration membrane during cardiopulmonary bypass

Background: Clinical practice of measuring colloid osmotic pressure (COP) was abandoned after correcting hypoosmolarity did not improve overall patient outcomes. However, the use of albumin and colloidal solutions has contributed to maintaining intraoperative and postoperative fluid balance at lower levels. Reduced perioperative fluid balance is consistently reported to have positive effects on clinical outcomes. Priming solutions for cardiopulmonary bypass typically include colloids; however, the optimal type of priming solution has not yet been determined. Stricter COP management may further improve postoperative courses. To achieve this, the widespread adoption of a measurement method suitable for COP monitoring during cardiopulmonary bypass is required. Methods: A test circuit was made which measured COP using an ultrafiltration membrane method based on the changes in hydrostatic pressure that occurs across a semipermeable membrane. We then compared the measurements obtained using this method with colloidal osmometer measurements. Results: COP measurements were obtained for a total of 100 tests (10 times each for 10 test solutions). The evaluation parameters included simultaneous reproducibility, correlation with the colloid osmometer, and measurement time. The results demonstrated high accuracy of the ultrafiltration membrane method, simultaneous reproducibility within 3%, a high positive correlation with the colloid osmometer (correlation coefficient: R2 = 0.99; p < 0.01), and equal time required for measurement. Conclusion: Measuring COP using ultrafiltration membranes solves problems within existing measurement methods. Although further improvements in the method are necessary, it has implications for future research and clinical applications.

Towards digital twins for safety demonstrations: Interfacing strategies for FPGA-targeted applications

For facilitating a framework of digital twins for safety demonstrations, this research paper identifies feasible interfacing strategies to connect a digital twin of novel all-electric actuation systems with safety-critical functions targeted for an FPGA device. The framework can improve safety demonstrations with a lifecycle perspective and one-to-one twinning if the values of the framework are realizable. For selecting a suitable interfacing strategy, the paper proposes five performance criteria to preserve the framework’s values while interfacing the controller logic with a digital twin. The paper introduces a safety-critical case study, thereby establishing reasoning, literature, and simulation testing of the interfacing strategies regarding relevant interfacing considerations and the performance criteria. We recommend using behavioral models during the design of FPGA firmware and commercial tools for verification against a reference model during the synthesizing steps. For the final development stage, we propose an FPGA-based digital twin, which offers high computational speed, scalability for integration testing, and comprehensive testing of the digital logical circuits. Implementing the recommendation requires practical implications, including adhering to FPGA configuration constraints and developing custom resources for interacting with the FPGA-based digital twin.

OSSP-PTA: An Online Stochastic Stepping Policy for PTA on Reinforcement Learning

DC analysis is essential and still quite challenging in large-scale nonlinear circuit simulation. Pseudo transient analysis (PTA) is a widely-used and has great potential solver in the industry. However, the PTA convergence and simulation efficiency is still seriously affected by its stepping policy. This paper proposes an online stochastic stepping policy (OSSP) for PTA based on deep reinforcement learning (DRL). To achieve better policy evaluation and stronger stepping exploration ability, the dual soft Actor-Critic agents work with the proposed valuation splitting and online momental scaling, enabling our OSSP to intelligently encode PTA iteration status and online further adjust forward and backward time-step size for unseen test circuits without human intervention and domain knowledge, trained solely by RL from self-search. Our public sample buffer and priority sampling are also introduced to overcome the sparsity and imbalance of sample data. Numerical examples demonstrate that the proposed OSSP achieves a significant efficiency speedup (up to 47.0X less NR iterations) and convergence enhancement on unseen test circuits compared with the previous iter-based and SER-based stepping methods, in just one stepping iteration.

Development and performance evaluation of reduced graphene oxide based all-flexible supercapacitors with open and short circuit tests

Development and performance evaluation of reduced graphene oxide based all-flexible supercapacitors with open and short circuit tests

Department of Elementary School Education Teacher Education, Satya Wiyata Mandala University, Nabire, Indonesia

Based on the problems that occur in badminton athletes for Merauke Regency PBSI, namely the difficulty for athletes to master badminton footwork and stroke movements due to the lack of badminton training facilities and infrastructure owned by PBSI Branch Merauke, so there is a need for a solution to overcome these problems. This research has the meaning: Knowing the effect of the Shadow Lamp Badminton Model as a Footwork and Stroke Training Tool for PBSI Merauke Badminton Athletes. The method in this research uses an experimental method in the form of a Quasi Experiment, namely the Non Randomized Control Group Pretest-Posttest Design. The subjects of this study were 14 PBSI Badminton Athletes in Merauke Regency, with male and female gender criteria. this research will find out the difference in these levels of ability of athletes in using the application of electronic knowledge in badminton sports to help athletes practice footwork and badminton strokes through shadow lamps and using conventional models. The instrument to measure the ability of footwork and stroke is the foot circuit test. the results of this research namely, footwork and stroke skills increased. get a significance result of 0.000 <0.05. This Badminton Model Shadow Lamp is effective as a Footwork and Stroke Training Tool for PBSI Merauke Badminton Athletes.

Polypyrrole/MoO3 composite as an appropriate anode of microbial fuel cell in both pulsed and permanent polarization with excellent performance

The surface of the graphite sheet is electrochemically modified with MoO3/polypyrrole composite (MoO3/PPy/Gr) to improve the performance of the anode of the microbial fuel cell (MFC) via strengthening the growth of the biofilm and increasing connection between the biofilm and the anode surface. Surface characterization of modified bioanode is investigated by Attenuated total reflection (ATR), The Energy Dispersive X-ray (EDX), and Field emission scanning electron microscopy (FE-SEM) analysis, where electrochemical evaluations are investigated with various tests such as various test circuits (VCR) test, chronopotentiometry, chronoamperometry, Electrochemical Impedance Spectroscopy (EIS). The MoO3/PPy/Gr bioanode, compared to PPy/Gr and MoO3/Gr bioanodes shows excellent performance given the capacitive behavior, generation of transient and permanent currents, and momentary intensity of the oxidation of organic materials. MFC equipped with MoO3/PPy/Gr bioanode shows a maximum power density of 380 mW/m2 in permanently current mode, 1.65 and 3.3 times the power density obtained using PPy/Gr and Gr bioanodes, respectively. Chronopotentiometry evaluations display that the specific capacitance for MoO3/PPy/Gr bioanode is 1454 mF/cm2, more than PPy/Gr and Gr (1000 and 695 mF/cm2, respectively).

Junction temperature prediction method of GaN HEMT power devices based on accurate on-voltage testing

Compared with Si devices, GaN HEMT has lower on-resistance, lower junction capacitance, higher switching frequency, higher switching speed and higher junction temperature capability. It is widely used in automotive, aerospace and other fields. Severe environments may cause the junction temperature of GaN-HEMT to be too high, and excessive temperature is the main reason for power device failure. In order to ensure stable operation of GaN devices under harsh conditions, it is important to extract junction temperature information of semiconductor devices simply and effectively. However, most of the existing junction temperature prediction methods are not applicable to GaN HEMT devices due to its high switching speed and high requirement of prediction accuracy. Thus, we proposed a new method based on an accurate on-voltage clamp circuit to predict the junction temperature of GaN HEMT devices. The interrelation between the on-resistance and the junction temperature is analyzed, and the temperature coefficient is calibrated to obtain the corresponding relationship between the characterization quantity and the junction temperature. The on-resistance testing circuit suitable for GaN device is given and analyzed in detail. Finally, the conduction resistance testing circuit is used to predict the junction temperature of GaN devices, achieving extremely high accuracy. Experiments have verified under 100 ℃, the predicted junction temperature and the actual junction temperature have achieved more than 90% coincidence.

Adolescent neurostimulation of dopamine circuit reverses genetic deficits in frontal cortex function

Dopamine system dysfunction is implicated in adolescent-onset neuropsychiatric disorders. Although psychosis symptoms can be alleviated by antipsychotics, cognitive symptoms remain unresponsive and novel paradigms investigating the circuit substrates underlying cognitive deficits are critically needed. The frontal cortex and its dopaminergic input from the midbrain are implicated in cognitive functions and undergo maturational changes during adolescence. Here, we used mice carrying mutations in Arc or Disc1 to model mesofrontal dopamine circuit deficiencies and test circuit-based neurostimulation strategies to restore cognitive functions. We found that in a memory-guided spatial navigation task, frontal cortical neurons were activated coordinately at the decision-making point in wild-type but not Arc-/- mice. Chemogenetic stimulation of midbrain dopamine neurons or optogenetic stimulation of frontal cortical dopamine axons in a limited adolescent period consistently reversed genetic defects in mesofrontal innervation, task-coordinated neuronal activity, and memory-guided decision-making at adulthood. Furthermore, adolescent stimulation of dopamine neurons also reversed the same cognitive deficits in Disc1+/- mice. Our findings reveal common mesofrontal circuit alterations underlying the cognitive deficits caused by two different genes and demonstrate the feasibility of adolescent neurostimulation to reverse these circuit and behavioral deficits. These results may suggest developmental windows and circuit targets for treating cognitive deficits in neurodevelopmental disorders.

Adolescent neurostimulation of dopamine circuit reverses genetic deficits in frontal cortex function.

Dopamine system dysfunction is implicated in adolescent-onset neuropsychiatric disorders. Although psychosis symptoms can be alleviated by antipsychotics, cognitive symptoms remain unresponsive and novel paradigms investigating the circuit substrates underlying cognitive deficits are critically needed. The frontal cortex and its dopaminergic input from the midbrain are implicated in cognitive functions and undergo maturational changes during adolescence. Here, we used mice carrying mutations in Arc or Disc1 to model mesofrontal dopamine circuit deficiencies and test circuit-based neurostimulation strategies to restore cognitive functions. We found that in a memory-guided spatial navigation task, frontal cortical neurons were activated coordinately at the decision-making point in wild-type but not Arc-/- mice. Chemogenetic stimulation of midbrain dopamine neurons or optogenetic stimulation of frontal cortical dopamine axons in a limited adolescent period consistently reversed genetic defects in mesofrontal innervation, task-coordinated neuronal activity, and memory-guided decision-making at adulthood. Furthermore, adolescent stimulation of dopamine neurons also reversed the same cognitive deficits in Disc1+/- mice. Our findings reveal common mesofrontal circuit alterations underlying the cognitive deficits caused by two different genes and demonstrate the feasibility of adolescent neurostimulation to reverse these circuit and behavioral deficits. These results may suggest developmental windows and circuit targets for treating cognitive deficits in neurodevelopmental disorders.

Study on debugging of lightning impulse voltage waveform for large capacity ±800kV converter transformer in high altitude area

The Qinghai-Henan ±800kV UHV DC power transmission project is an UHV channel specially constructed for clean energy delivery, ±800kV converter transformers of the project are assembled and tested in Xining at an altitude of 2500 m, full-wave lightning impulse test is one of the main means to evaluate converter transformer insulation performance, its valve side lightning impulse voltage waveform parameters often fail to meet IEC60076-3 standards because of the large winding to the ground capacitance. In order to effectively assess the lightning tolerance of converter transformer, a simulation model of impulse test circuit of ±800kV converter transformer was built based on the existing 6000kV/560kJ impulse voltage generator and ATP-EMTP simulation software, three kinds of optimization methods are proposed, which include increasing the wavetail resistance, increasing load capacitor, and connecting the wave head in parallel with different inductors, the results show that the single optimization method can not meet the waveform requirements. Therefore, a combinatorial optimization test method of increasing the wavetail resistance and connecting the wave head in parallel with different inductors is proposed, which is completed and verified in the full-wave lightning impulse test on the valve side of Qinghai ±800kV high-end converter transformer, the results show that the optimized test waveform parameters meet the standard requirements.

Design of current steering logic CMOS circuit

The current-mode CMOS technology has many positive identities, while traditional current-mode CMOS circuits designing methods is comparatively more complex than voltage-mode CMOS. In this paper, using threshold logic, a current-mode CMOS circuits designing method based on spectral techniques is proposed. The proposed method is capable of designing combinational logic current-mode CMOS circuits. The sequential logic current-mode CMOS circuits can also be designed with the designed combinational logic current-mode CMOS circuit. The designed circuit is steered only by current signals. By using both simulations and real circuit tests, we proved the effectiveness of the proposed circuit designing method. Using HSPICE simulations, the designed circuit is proven to have advantages including lower circuit power consumption and higher stability of the current through power supply compared with voltage-mode CMOS and other main current-mode CMOS circuits, and the designed circuits require less control signals than other major current-mode CMOS circuits.

Research on the Co-simulation System of Subway Control Circuits

In order to solve the problems of complex control logic and the difficulty of simulating function modules due to the high coupling degree of subway control circuits, a subway control circuit co-simulation system is designed in this paper. By analysing the components data and connection relationship in the subway control circuit schematic diagrams, the network topologies are automatically generated, and the mathematical relationships between nodes, branches and components states are established, so as to build a complete logical control model. The depth-first search (DFS) algorithm is adopted to search the effective path across the topology, the event management unit is added to solve the linkage control of the relay, and the logic function simulation of the function module is realized by embedded script. Finally, the feasibility of the simulation system is verified through the simulation test of the subway door control circuits and the analysis of the simulation results. The system is conducive to the functional test and algorithm verification at the subway design stage, and has a good application prospect in the field of subway driver training.

Switching Strategy to Reduce Inductor Current Ripple and Common Mode Voltage in Quasi Z-Source Ultra Sparse Matrix Converter

This paper aims to reduce the ripple current in the inductor used in a Quasi Z-source Ultra Sparse Matrix Converter (QZSUSMC). The main limitations of the conventional Ultra Sparse Matrix Converter (USMC) are limited voltage gain <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$(\leq 0.866)$</tex-math></inline-formula> and high common mode voltage (CMV). By integrating a quasi Z-source network in the DC link of USMC and providing a shoot-through (ST) state in a switching cycle, a voltage gain greater than unity can be achieved. Inductors are magnetised during the ST state and demagnetized during the nonshoot-through (NST) state. Hence with a proper arrangement of the ST and NST states, ripple in the inductor current can be minimised. In the proposed modulation, the total ST time is divided into six unequal parts and arranging them to minimize the inductor ripple current. in addition to it, proposed method also offers proper switching arrangements by using active vectors to attenuate peak-peak common mode voltage (CMV). As compared to the earlier reported methods, the proposed method produces a better inductor current ripple and a reduced peak of the CMV. Simulation and developed testing circuit results show the effectiveness of the proposed method.