This work continues our investigation regarding the philosophy and the implementation of a new technology entitled Solderless Assembly for Electronics Technology (SAFE) or Occam [1]. Are presented the results of thermal analysis and... more
This work continues our investigation regarding the philosophy and the implementation of a new technology entitled Solderless Assembly for Electronics Technology (SAFE) or Occam [1]. Are presented the results of thermal analysis and measurements of electronic circuits, realized in Occam technology, compared to “classical” electronic modules realized on FR4. In the first case the convection from the top of component is blocked by the molding process. In the second case, free convection from top of component is considered. In both cases, the interconnection of components should be realized using printed conductive paste, as in the modified variant proposed in [1]. In this way, the heat generation in electronic components, in our case mid power LEDs, will be added with the supplemental dissipation caused by the current flow. For comparison purposes, there were investigated structures containing fixed linear resistors and/or structures printed on flat substrates.
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The paper presents a method of modelling the optical behaviour of the optoelectronic devices, such as Light Emitting Diodes and Photo Diodes, in order to handle the optical signals in the PSpice environment.
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In mixed-signal integrated circuits, interference between digital noisy and sensitive analog/RF circuits is a challenging performance issue. The high cost of chip fabrication requires accurate simulation of the circuits’ performance... more
In mixed-signal integrated circuits, interference between digital noisy and sensitive analog/RF circuits is a challenging performance issue. The high cost of chip fabrication requires accurate simulation of the circuits’ performance versus signal and noise integrity. In this paper, a substrate crosstalk noise analysis flow is described and the characteristics of the substrate noise coupling mechanism are analyzed. The proposed noise integrity aware simulation flow properly estimates the substrate coupling effect and predicts the analog/RF victim circuit performance degradation due to noise coupling mechanisms. The methodology is implemented seamlessly in the current standard virtuoso-based design suite and is used in parallel with any commercial design tool, compatible with the standard analog/RF simulation process. The efficiency of the proposed methodology is validated by a full substrate crosstalk aware system on chip vehicle, designed in an RFCMOS 65 nm process. Silicon substrat...
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The paper presents virtual investigation studies of a stand-alone Photovoltaic (PV) system with a supercapacitor bank, used for powering an irrigation system. It powers two water pumps of 200W each, with input power varying from 50W to... more
The paper presents virtual investigation studies of a stand-alone Photovoltaic (PV) system with a supercapacitor bank, used for powering an irrigation system. It powers two water pumps of 200W each, with input power varying from 50W to 350W. An algorithm was developed for controlling the charging and discharging of supercapacitors, in order to optimize the operation of the water pumps. Next, an equivalent electric circuit is created, and SPICE simulations are performed in the Micro-Cap environment. Two scenarios are investigated, using 300F and 250F supercapacitor banks, rated at 27V and 32V, respectively. Furthermore, for each scenario, the capacitors charging/discharging currents during the different operation regimes are assessed. The results showed that the maximal currents during the worst-case scenarios are within (12.3–16.6) A. Another important parameter that was investigated is the minimum operating time of the pumps during “sudden absence of power” for the two scenarios −59s and 141s, respectively.
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Photovoltaic energy conversion is today a very hot topic. The technical solutions are already on the market, the silicon crystalline or amorphous being the most used solar cells. We present in the paper investigations on a promising... more
Photovoltaic energy conversion is today a very hot topic. The technical solutions are already on the market, the silicon crystalline or amorphous being the most used solar cells. We present in the paper investigations on a promising different type of solar cell called Dye-sensitized solar cell (DSSC)[1]. This cell presents different construction and operation principles from silicon cells and is presented as a possible solution for large area or flexible panels. We present here electrical measurements on three DSSC prototype samples, compared with a commercial silicon cell, for different illumination levels. The voltage-current characteristics and the main parameters of the cells, as short circuit current, open circuit voltages, maximum power point (MPP) are comparatively presented in the paper.
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The present paper continues our investigations in the field of Supercapacitors or Electrochemical Double Layer Capacitors, briefly named EDLCs. The series connection of EDLCs is usual in order to obtain higher voltage levels. The inherent... more
The present paper continues our investigations in the field of Supercapacitors or Electrochemical Double Layer Capacitors, briefly named EDLCs. The series connection of EDLCs is usual in order to obtain higher voltage levels. The inherent uneven state of charge (SOC) and manufacturing dispersions determine during charging at constant current that one of the capacitors reaches first the rated voltage levels and could, by further charging, be damaged. The balancing circuit with resistors and transistors used to bypass the charging current can be improved using the proposed circuit. We present here a complex variant, based on integrated circuit acting similar to a microcontroller. The circuit is adapted from the circuits investigated in the last 7–8 years for the batteries, especially for Lithium-ion type. The test board built around the circuit is performant, energy efficient and can be further improved to ensure the balancing control for larger capacitances.
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These days many variants for lighting systems are available on the market, and new solutions are about to emerge. Most of the new lamps are offered in form to be retrofitted to existing sockets and luminaires. In this paper, are presented... more
These days many variants for lighting systems are available on the market, and new solutions are about to emerge. Most of the new lamps are offered in form to be retrofitted to existing sockets and luminaires. In this paper, are presented some systematically investigations on different lamps as LEDs, Compact Fluorescent Lamps (CFLs), tungsten, and new available Cold Cathode Fluorescent Lamps (CCFLs), regarding the light level, dimming performances and also the resulting flicker and power distortion performances. The light level was expressed by the illuminance level, measured for all lamps in the same conditions, at the same distance and on the same surface represented by the photometer probe.
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The paper is a part of a larger study regarding reliability aspects of high power DMOS (Double-diffused MOS) transistors, as part of automotive integrated electronics. When submitted to high transient loads, the junction temperature of... more
The paper is a part of a larger study regarding reliability aspects of high power DMOS (Double-diffused MOS) transistors, as part of automotive integrated electronics. When submitted to high transient loads, the junction temperature of these devices suffers large excursion from ambient to 350°C, strongly influencing the reliability. Authors present in the paper the results of thermal transient analysis of a PCB (Printed Circuit Board) test structure containing 8 CERDIP (CERamic Dual In line Package) components on the board. The investigations are performed using FEM (Finite Element Method) analysis, the main results being the time evolutions of temperature in different locations of the board, including the chip active area. These time results are used as input data for thermal impedance calculations and for further simulations based on SPICE type programs.
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This paper presents some results of European projects for improvement and innovation of engineering education. It summarizes the application of performance support systems, previously used only for company training, in higher education... more
This paper presents some results of European projects for improvement and innovation of engineering education. It summarizes the application of performance support systems, previously used only for company training, in higher education and discusses its advantages. The development of distributed in four European countries performance-centred learning system for information technology, telecommunication, and microelectronics is also presented. As the practice in engineering education is crucial, virtual laboratories with demonstrations, animations and simulations were developed as well as laboratories with remote access to real experiments. Finally, our recent work on the creation of microelectronics Cloud system in nine European countries is presented by an example of building cloud nodes at an installation site.
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In this paper, a sensor using modified Split Ring Resonators (SRRs) is designed, simulated, fabricated, and used for advanced investigation and precise measurements of the real part and imaginary part solid dielectrics’ permittivity.... more
In this paper, a sensor using modified Split Ring Resonators (SRRs) is designed, simulated, fabricated, and used for advanced investigation and precise measurements of the real part and imaginary part solid dielectrics’ permittivity. Adding vertical strips tightly coupled to the outer ring of the SRR leads to the appearance of two resonant frequencies at 1.24 GHz and 2.08 GHz. This modified geometry also assures an improved sensitivity. Using the full wave electromagnetic solver, both the unloaded and loaded sensors are investigated. The numerical simulations are used to develop a mathematical model based on a curve fitting tool for both resonant frequencies, allowing to obtain analytical relations for real and imaginary parts of permittivity as a function of the sample’s thickness and quality factor. The sensor is designed and fabricated on 1.6 mm thick FR-4 substrate. The measurements of different samples, such as transparent glass, acrylic glass, plexiglass, and Teflon, confirm t...
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ABSTRACT This paper continues the study in the field of microheaters on flexible substrates. The idea of using flexible substrates comes together with the need for low manufacturing costs, having in mind the applications of sensors for... more
ABSTRACT This paper continues the study in the field of microheaters on flexible substrates. The idea of using flexible substrates comes together with the need for low manufacturing costs, having in mind the applications of sensors for home usage and other possible applications as monitors for buildings or basements where possible toxic gases can be accumulated, for instance mathane, carbon monoxide or carbon dioxide. In the current paper we propose the use of poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonic acid (PEDOT:PSS) as active heating element. The data from literature and our previous experiments have proven that this material can be used as resistive material having the possibility to operate within the desired range of temperatures for sensor applications, between 80 and 100 °C. The test samples with different patterns will be prepared by ink-jetting, with silver ink used as terminations.
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The present stage of development of electronics technology there is an increased interest in the study of new materials used as solder that replaces the already banned tin-lead alloy. Many investigations were done in direction of... more
The present stage of development of electronics technology there is an increased interest in the study of new materials used as solder that replaces the already banned tin-lead alloy. Many investigations were done in direction of metallurgic compatibility between the printed circuit board finishing, component terminal finishing and solder itself. Other studies are taken in direction of mechanical characterization of lead free alloys. We propose a study from electrical point of view. So we will analyze the current capabilities of solder joints by thermographical investigations. The finite conductivity of the solder alloy will act as a dissipating media and will heat the adjacent region to the joint. In order to make this effect more pregnant it is necessary to dispose of very precise low-ohm resistors and to pass through them relatively high currents. Based on a high resolution infrared camera the temperature gradient will be better observed. The measured results are compared to the results derived from finite element modeling and simulation. In the simulations, the whole D structure of solder joint is modeled. It has practically a very complex shape and is difficult to be analyzed using other methods. Our tests will be realized on organic rigid substrates using a configuration that was intended to characterize the solder joint dissipation. The data derived from this analysis will be very useful in the design process of high power circuits that could be used in advanced electronic modules.
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Teaching the design of microsystem packages is one of the most important topics in the BSc and MSc level university education of electronic engineering. Special emphasis should be laid on teaching design, according to the general opinion... more
Teaching the design of microsystem packages is one of the most important topics in the BSc and MSc level university education of electronic engineering. Special emphasis should be laid on teaching design, according to the general opinion that industrial companies are suffering from a shortage of design engineering staff. In addition to providing courses on CAD design in regular university curricula, courses and training should be developed and provided for industrial engineers. The aim of such courses is to bridge the gap between the knowledge that is provided by the different undergraduate modules and that which is necessary and relevant for the industrial labor market and/or requested by the graduate educational modules for further qualification. Internet accessible, interactive, multimedia equipped, distant learning virtual laboratory experiments have to be offered for exploratory training to improve the knowledge of industrial engineers. The present paper reviews a part of a course that tries to meet these requirements.
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Extremely quick progress in miniaturisation of electronic components determine PCB producers to research of new material and technological solutions. Indispensable element of present HDI PCB's are interlayer connections by using... more
Extremely quick progress in miniaturisation of electronic components determine PCB producers to research of new material and technological solutions. Indispensable element of present HDI PCB's are interlayer connections by using microvia techniques. Drilling by laser beam is one from manners of formation microvia. The use of UV laser permit sequentionally but in one technological operation, to open window in copper
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ABSTRACT The need for low cost gas sensors has been required especially for home usage. Possible applications are, in buildings or basements where possible toxic gases can be accumulated, for example carbon monoxide, carbon dioxide,... more
ABSTRACT The need for low cost gas sensors has been required especially for home usage. Possible applications are, in buildings or basements where possible toxic gases can be accumulated, for example carbon monoxide, carbon dioxide, methane. This paper presents a first step in developing gas sensors based on impedance measurements. For optimal sensor operation a heater that should ensure uniform heating of the structure is required. We have proposed and realized a series of three geometries with different materials that will serve as heaters for future sensor development. The element of novelty consists in the use of flexible substrates. The heater will be supplied with appropriate voltage in order to obtain a working temperature between 80 and 100 °C. The temperature distribution was firstly simulated and subsequently measured by thermographical methods.
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ABSTRACT The organic electronics products becomes every day more and more present, especially known being organic light emitting diodes (OLED), organic photovoltaic cells (OPV) or organic thin film transistors (OFET). It is very important... more
ABSTRACT The organic electronics products becomes every day more and more present, especially known being organic light emitting diodes (OLED), organic photovoltaic cells (OPV) or organic thin film transistors (OFET). It is very important to have a reliable solution for interconnection of these devices in a manner similar to printed circuit boards. This paper will present results on electrical and thermal tests of organic conductors based on poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonic acid (PEDOT:PSS) that can be used for data and power tracks. The samples are, and will be prepared by screen printing and ink-jetting, having silver paste and respectively ink based terminations. The results have shown that the current capabilities of PEDOT:PSS organic conductive tracks are limited by the dissipated power, due to relatively large resistance. As expected, the screen printed tracks having a higher thickness will have lower resistance. The temperature coefficient (TCR) has been found negative around -1000 ppm/°C.