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ABSTRACT A complete over-current and short-circuit protection system for Low-Drop Out (LDO) regulator applications is presented. The system consists of a current-sense circuit, a current comparator, a D Flip-Flop, an OR logic gate and the... more
ABSTRACT A complete over-current and short-circuit protection system for Low-Drop Out (LDO) regulator applications is presented. The system consists of a current-sense circuit, a current comparator, a D Flip-Flop, an OR logic gate and the short-circuit sense topology. The protection circuit is able to shut down the LDO rapidly by producing a control signal when an over-current event occurs while during the normal operation of the LDO, the protection circuit is idle. The restart of the LDO has to be made manually and a master Reset signal is, also, available. The proposed protection system was designed by using a standard 0.18u CMOS technology using high-voltage transistors.
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User generated content and especially customer-generated reviews are becoming a prominent information source for travellers making hotel booking decisions. Building upon the dimensions of the SERVQUAL model, the aim of this study is to... more
User generated content and especially customer-generated reviews are becoming a prominent information source for travellers making hotel booking decisions. Building upon the dimensions of the SERVQUAL model, the aim of this study is to identify why hotel customers have disparate opinions regarding perceived service quality during their stays. In order to do so, we distinguish between high and low absolute priced hotels. We adopt this categorisation based on prior studies, which identify price as a strong determinant of hotel customers' perceptions and decisions. By applying qualitative data analysis methods on customer reviews from one of the world's leading online hotel reservation agencies (Booking.com), we show that absolute price has an impact on how customers perceive various dimensions of service quality. In particular, the number of positive reviews is significantly different for low and high priced hotels when examining the dimensions of tangibility and empathy. Addi...
Polysilicon thin-film technology has become of great interest due to the demand for large area electronic devices. Display applications, memories and optical copier are among the fields where polysilicon thin-film transistors (poly-Si... more
Polysilicon thin-film technology has become of great interest due to the demand for large area electronic devices. Display applications, memories and optical copier are among the fields where polysilicon thin-film transistors (poly-Si TFTs) are most commonly used. However the design of analogue blocks, by using Poly-Si TFTs, with constant specifications is very difficult because of the large variation of the
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In this paper the operation of the pass transistor for rising ramp signals in both terminal inputs, is analyzed. The differential equation of the circuit structure is solved, making the appropriate approximations, and analytical formulas... more
In this paper the operation of the pass transistor for rising ramp signals in both terminal inputs, is analyzed. The differential equation of the circuit structure is solved, making the appropriate approximations, and analytical formulas for the output voltage is derived. Second order effects for nanoscale devices are taking into account. Comparison results with SPICE simulations are shown for various circuit configurations. The proposed model presents very good accuracy for 90nm and 65mn technologies.
AbstractA new bias current generator (BCG) with threshold voltage compensation for analog circuit design implemented with low-temperature polycrystalline silicon thin-film transistors (LT poly-Si TFTs) is proposed. The proposed topology... more
AbstractA new bias current generator (BCG) with threshold voltage compensation for analog circuit design implemented with low-temperature polycrystalline silicon thin-film transistors (LT poly-Si TFTs) is proposed. The proposed topology can be used in AMOLED display ...
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ABSTRACT The performance of n-channel symmetrical double-gate (DG) polycrystalline silicon thin-film transistors (polysilicon TFTs) has been investigated with 2-D device simulations. The simulations were conducted based on device... more
ABSTRACT The performance of n-channel symmetrical double-gate (DG) polycrystalline silicon thin-film transistors (polysilicon TFTs) has been investigated with 2-D device simulations. The simulations were conducted based on device characteristic properties, extracted from fabricated single-gate (SG) polysilicon TFTs. Through fitting of the test SG devices, a unique set of density of states was identified, that characterizes the particular technology used. The obtained results reveal that DG TFTs, due to their enhanced gate controllability, exhibit steeper subthreshold slope, lower threshold voltage, higher driving current and better device uniformity compared to their SG counterparts. Implementation of DG TFTs in 2T1C active matrix circuit show that the response time of the circuit can be improved by eight times compared with the conventional SG TFTs and exhibit more stable driving capability due to the improved device uniformity.
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A simple current-voltage model for polysilicon thin-film transistors (TFTs) is proposed, including the sixth-order polynomial function coefficients fitted to the effective mobility versus gate voltage data, the channel length modulation... more
A simple current-voltage model for polysilicon thin-film transistors (TFTs) is proposed, including the sixth-order polynomial function coefficients fitted to the effective mobility versus gate voltage data, the channel length modulation and the impact ionization effect. The model possesses continuity of current in the transfer characteristics from weak to strong inversion and in the output characteristics throughout the linear and saturation
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A simple unified analytical compact drain current model for undoped (or lightly doped) triple-gate FinFETs is presented, functional for all regions of operation. A unified normalized sheet charge density is used where the behavior of the... more
A simple unified analytical compact drain current model for undoped (or lightly doped) triple-gate FinFETs is presented, functional for all regions of operation. A unified normalized sheet charge density is used where the behavior of the subthreshold region is embedded within the expressions commonly used to describe the inversion region. The model can be used as a basis for the
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An analytical compact drain current model for undoped (or lightly doped) short-channel triple-gate (TG) FinFETs is presented, taking into account quantum mechanical and short-channel effects such as threshold voltage shift, drain-induced... more
An analytical compact drain current model for undoped (or lightly doped) short-channel triple-gate (TG) FinFETs is presented, taking into account quantum mechanical and short-channel effects such as threshold voltage shift, drain-induced barrier lowering and subthreshold slope degradation. In the saturation region, the effects of series resistance, surface-roughness scattering, channel-length modulation and saturation velocity were also considered. The proposed model has
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This paper studies the operation of the pass transistor structure taking into account secondary effects which become intense in nanoscale technologies. The different regions of operation are determined and the differential equation which... more
This paper studies the operation of the pass transistor structure taking into account secondary effects which become intense in nanoscale technologies. The different regions of operation are determined and the differential equation which describes the pass transistor ...
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ABSTRACT A new current-programmed pixel design for AMOLED displays is presented in this manuscript. The proposed pixel is designed by using organic thin-film transistors and it exhibits high immunity to the threshold voltage variations of... more
ABSTRACT A new current-programmed pixel design for AMOLED displays is presented in this manuscript. The proposed pixel is designed by using organic thin-film transistors and it exhibits high immunity to the threshold voltage variations of the transistors threshold voltage shift, caused by the bias stress and the intrinsic properties of the organic materials. The pixel's main advantages are the fact that it can be designed by using entirely n- type or p-type TFTs meaning that all the organic TFTs technologies can be applied and the small settle time. Therefore, the proposed pixel can be used in high performance displays with high refresh rate.
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ABSTRACT In this paper the operation of the pass transistor driving RC loads is investigated for nanoscale technologies. The widely accepted CRC π-model is used for the representation of RC loads. The different operational conditions of... more
ABSTRACT In this paper the operation of the pass transistor driving RC loads is investigated for nanoscale technologies. The widely accepted CRC π-model is used for the representation of RC loads. The different operational conditions of the circuit are determined and the differential equations which describe its operation are solved analytically. Appropriate approximations are used for the current waveforms to simplify the modeling procedure without significant influence in the accuracy. The evaluation of the model is made through comparisons with HSpice simulation results and by using three different technologies: CMOS 65 nm, 32nm and 32 nm with high-k dielectric.
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ABSTRACT A new method for the extraction of the backscattering coefficient in nanoMOS devices has been demonstrated. The method, which relies on mobility measurements in linear operation, proves very simple and reliable for the... more
ABSTRACT A new method for the extraction of the backscattering coefficient in nanoMOS devices has been demonstrated. The method, which relies on mobility measurements in linear operation, proves very simple and reliable for the determination of the ballistic rate of transport. Moreover, it allows to obtain the drift-diffusion mobility corrected from ballistic effects and therefore to make a diagnostic of the scattering mechanisms at small gate length.
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1 Electronics Lab., Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 2 Solid State Section, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 3 Institute of... more
1 Electronics Lab., Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 2 Solid State Section, Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 3 Institute of Microelectronics, Electromagnetic ...
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A new source follower type analog buffer used as an output buffer for the data / column driver of an Active Matrix display is presented in this paper. The proposed buffer is implemented with low temperature polycrystalline silicon thin... more
A new source follower type analog buffer used as an output buffer for the data / column driver of an Active Matrix display is presented in this paper. The proposed buffer is implemented with low temperature polycrystalline silicon thin film transistor (LT poly-Si TFTs) and the main advantage of the buffer is its high immunity to the threshold voltage variation of the LT poly-Si TFTs. The functionality of the buffer is verified through simulation with HSpice, using for the simulations parameters extracted from fabricated LT poly-Si TFTs in order to obtain realistic simulation results.
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A simple current-voltage model for polycrystalline silicon thin-film transistors (polysilicon TFTs) is proposed, including the sixth-order polynomial function coefficients fitted to the effective mobility versus gate voltage data, the... more
A simple current-voltage model for polycrystalline silicon thin-film transistors (polysilicon TFTs) is proposed, including the sixth-order polynomial function coefficients fitted to the effective mobility versus gate voltage data, the channel length modulation, and impact ionization effects. The model possesses continuity of current in the transfer characteristics from weak to strong inversion and in the output characteristics throughout the linear and
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AbstractThe static bias-stress-induced degradation of hydro-genated amorphous/nanocrystalline silicon bilayer bottom-gate thin-film transistors is investigated by monitoring the turn-on voltage (Von) and ON-state current (Ion) in the... more
AbstractThe static bias-stress-induced degradation of hydro-genated amorphous/nanocrystalline silicon bilayer bottom-gate thin-film transistors is investigated by monitoring the turn-on voltage (Von) and ON-state current (Ion) in the linear region of operation. Devices of constant ...
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ABSTRACT An analytical model for the drain current above threshold voltage, based on an exponential energy distribution of band tail states, has been applied to bottom-gated nanocrystalline silicon (nc-Si) thin-film transistors (TFTs).... more
ABSTRACT An analytical model for the drain current above threshold voltage, based on an exponential energy distribution of band tail states, has been applied to bottom-gated nanocrystalline silicon (nc-Si) thin-film transistors (TFTs). Analysis of the model shows that the slope of the exponential band tails determines the behavior of the device current-voltage characteristics. Comparison with experimental data shows that few fundamental model parameters, related to the material quality and different physical effects, can be used to describe consistently both output and transfer characteristics of nc-Si TFTs over a wide range of channel lengths.
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ABSTRACT The influence of the light illumination on the drain current of polycrystalline silicon thin-film transistors has been studied and mathematically modeled in our previous work [1]. This paper introduces a simple circuit model for... more
ABSTRACT The influence of the light illumination on the drain current of polycrystalline silicon thin-film transistors has been studied and mathematically modeled in our previous work [1]. This paper introduces a simple circuit model for the integration of the mathematical model in the SPICE circuit simulation program, making, thus, possible its immediate exploitation for circuit design. Comparative results between measurements and simulated performance are presented, showing the efficient accuracy of the circuit model.
ABSTRACT User Generated Content (UGC) and especially customer-generated reviews are becoming a prominent information source for travelers making hotel purchase decisions. In this study, the dimensions of the wellknown SERVQUAL construct... more
ABSTRACT User Generated Content (UGC) and especially customer-generated reviews are becoming a prominent information source for travelers making hotel purchase decisions. In this study, the dimensions of the wellknown SERVQUAL construct were combined with the general and important dimension of convenience in order to address perceived service quality. As prior studies have revealed that room price influences hotel customers' decisions, customer-generated reviews were used to measure differences between cheap and ...