Modeling and estimating leakage current in series-parallel CMOS networks

Author(s):  
Paulo F. Butzen ◽  
Andre I. Reis ◽  
Chris H. Kim ◽  
Renato P. Ribas
Keyword(s):  
Author(s):  
I.V. Frolov ◽  
◽  
V.A. Sergeev ◽  
A.M. Hodakov ◽  
S.A. Zaytsev ◽  
...  

The paper presents the results of studies of changes in the characteristics of LED COB matrices of the GW P9LR31.EM - DURIS S 8 type as part of a LED luminaire when tested under the direct current in a continuous mode and in an electrocycling mode. The arrays consist of eight InGaN/GaN LED dies connected in series, coated with a phosphor. Calculation in the Comsol Multiphtsics environment of the temperature field of the luminaire at the rated operating current and free convection heat transfer showed that the maximum overheating of the matrices does not exceed 46 K, and the difference in their temperatures is 2 K. At the same time, the experimental values of the thermal resistances of the matrices of a real lamp vary from 42 to 58 K/W. Before testing, the I-V characteristics of the matrices differ markedly in the level of leakage current in the voltage range from 14 V to 19 V, and the LEDs in the luminaire matrices have a significant spread in the brightness of emission in the microcurrent mode. The degree of this scatter within each matrix was estimated by measuring the luminescence brightness of each die of the matrix and calculating the coefficient of variation γ. It was found that the coefficient of variation of the emission brightness of the COB matrix dies measured at a current of 100 nA strongly correlates with the leakage current. When testing a luminaire under the direct current, the most significant changes in the electrophysical and optical characteristics of COB matrices are observed in the range of microcurrents: the distribution of the emission brightness of the matrix dies at a current of 100 nA becomes more uniform. The greatest changes in matrix characteristics were observed after the first 700 hours of testing, that is, at the running-in stage. At the same time, no correlation was found between the degree of change in the characteristics of the matrices during tests and their thermal resistances.


Author(s):  
Raphael Borges Nobrega ◽  
Valmir Nascimento Júnior ◽  
Ítalo Oliveira Medeiros ◽  
Edson Guedes Costa ◽  
Ronimack Trajano Souza

<p>This paper aimed at the design and development of a data acquisition and control system using the Arduino open-source platform to automate equipment responsible for the IEC 60587 electrical tracking and erosion test. The developed system allows the selection of protection resistors specified by the standard from the voltage value informed by the operator, monitoring of the leakage current flowing over five samples simultaneously tested and automatically interrupts the samples if the leakage current exceeds 60 mA for more than two seconds. The leakage current values are measured indirectly from the voltage drop across 50 Ω shunt resistors installed in series with each sample. The voltage values on the shunt resistors are conditioned by a measuring circuit that allows the voltage level to be adjusted to the analog inputs of the microcontroller, ie, between 0 V and 5 V. The microcontroller treatment performs the voltage signal obtained by the measuring circuit, the calculation of the RMS value of the current and stop criterion monitoring the leakage current. The calibration of the leakage current measurement circuit was performed by comparing voltage values measured by a digital oscilloscope for four different alternate waveforms and values up to 5 Vrms, corresponding to currents up to 100 mA. The results showed that the circuit provided measurements close to the values measured by the oscilloscope, with errors below 11%. For current values between 30 mA and 80 mA, the errors were less than 6%.</p>


2016 ◽  
Vol 839 ◽  
pp. 114-118
Author(s):  
Nopphadol Sitthiphol ◽  
Chatchai Sirisamphanwong ◽  
Nipon Ketjoy ◽  
Kobsak Sriprapha

Thailand is located in the tropical zone dominated by monsoons for more than six months in a year. These climatic conditions illustrate elevated relative humidity and temperature that contributes to Potential Induced Degradation (PID). Humidity has been reported to be potential cause of degradation in the systems with high voltages. Moisture helps leakage currents in passing through laminate permeation and back sheet from cell to ground frame. The PID occure in PV systems when connected in series using DC voltages of high orders. This research shows comparisons of both PV systems, with negative grounding and floating grounding with a system voltage about 800 Vdc. Investigations of insulation resistance (MΩ) in PV strings and modules after two years operation has been done. It was found that the decrement in average insulation resistance (MΩ) of PV string using negative grounding, floating grounding was 14.5 MΩ, 11.0 MΩ and average leakage current per string was 68.9 µA, 90.9 µA respectively. Moreover, the wet leakage current per module showed the decrement in average insulation resistance (MΩ.m2) was 174 MΩ.m2, 133 MΩ.m2 and average leakage current per module was 5.75 µA, 7.51 µA respectively.


1991 ◽  
Vol 240 ◽  
Author(s):  
J. M. Freund ◽  
V. Swaminathan ◽  
M. W. Focht ◽  
G. D. Guth ◽  
G. J. Przybylek ◽  
...  

The self-electro-optic effect device (SEED) and the symmetric SEED (S-SEED) have demonstrated considerable applications for photonic switching and logic functionality. A SEED consists of a p-i-n, mesa diode, with a multiple-quantum-well structure for the i region. The symmetric SEED consists of two p-i-n mesa diodes connected in series. The S-SEED has been fabricated in functional arrays containing as many as 32×64 elements. The SEED and S-SEED are operated under a reverse bias, thus low reverse leakage is desired. As the magnitude of the reverse leakage current increases, more incident laser power is required to switch device states and then hold that state. Therefore, understanding the origins of the reverse leakage current and its dependence on mesa and array size is imperative for optimizing device performance.


2010 ◽  
Vol 56 (6) ◽  
pp. 362-366 ◽  
Author(s):  
Vaibhav Neema ◽  
Shailesh Singh Chouhan ◽  
Sanjiv Tokekar

2020 ◽  
Vol 63 (9) ◽  
pp. 2921-2929
Author(s):  
Alan H. Shikani ◽  
Elamin M. Elamin ◽  
Andrew C. Miller

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance ( R airflow ) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow ( Q ) amplitude and R airflow , as indicated by a pressure drop ( P Drop ) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T 0 ) and after 24 hr of moisture testing (T 24 ) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T 0 and T 24 ). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.


Author(s):  
S. P. Bersenev ◽  
E. M. Slobtsova

Achievements in the area of automated ultrasonic control of quality of rails, solid-rolled wheels and tyres, wheels magnetic powder crack detection, carried out at JSC EVRAZ NTMK. The 100% nondestructive control is accomplished by automated control in series at two ultrasonic facilities RWI-01 and four facilities УМКК-1 of magnetic powder control, installed into the exit control line in the wheel-tyre shop. Diagram of location, converters displacement and control operations in the process of control at the facility RWI-01 presented, as well as the structural diagram of the facility УМКК-1. The automated ultrasonic control of rough tyres is made in the tyres control line of the wheel-tyre shop at the facility УКБ-1Д. The facility enables to control internal defects of tyres in radial, axis and circular directions of radiation. Possibilities of the facility УКБ-1Д software were shown. Nondestructive control of railway rails is made at two facilities, comprising the automated control line of the rail and structural shop. The УКР-64Э facility of automated ultrasonic rails control is intended to reveal defects in the area of head, web and middle part of rail foot by pulse echo-method with a immersion acoustic contact. The diagram of rail P65 at the facility УКР-64Э control presented. To reveal defects of the macrostructure in the area of rail head and web by mirror-shadow method, an ultrasonic noncontact electromagnetic-acoustic facility is used. It was noted, that implementation of the 100% nondestructive control into the technology of rolled stuff production enabled to increase the quality of products supplied to customers and to increase their competiveness.


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