• Journal of Power Electronics
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• 제18권2호
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• pp.640-650
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• 2018

A TRIAC dimmable LED driver with a wide tuning range and a two-stage uniform dimming scheme is proposed in this paper. To solve the restricted dimming range problem caused by the limited conduction ratio of TRIAC dimmers, a conduction ratio compensation technique is introduced, which can increase the output current up to the rated output current when the TRIAC dimmer turns to the maximum conduction ratio. For further optimization, a two-stage uniform dimming diagram with a rapid dimming curve and a slow dimming curve is designed to make the LED driver regulated visually uniform in the whole adjustable range of the TRIAC dimmer. The proposed control chip is fabricated in a TSMC $0.35{\mu}m$ 5V/650V CMOS/LDMOS process, and verified on a 21V/500mA circuit prototype. The test results show that, in the 90V/60Hz~132V/60Hz ac input range, the voltage linear regulation is 2.6%, the power factor is 99.5% and the efficiency is 83%. Moreover, in the dimming mode, the dimming rate is less than 1% when the maximum dimming current is 516mA and the minimum dimming current is only about 5mA.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.4.1-4.1
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• 2011

Recently, circuit printing technology has been considered as a promising alternative to conventional PCB fabrication, for it can greatly reduce the manufacturing costs. Even though printed circuit has many advantages over typical subtractive technology such as fewer processes, it has some disadvantages. The major problems are low adhesion and poor resolution. Efforts to overcome these problems have been mainly focused on ink developments with a limited success. And surface treatments showed some improvements. Therefore, various plasma treatments and primer coatings on plastic substrates have been tested. Plasma treatments using hydrocarbon gases including methane and propane improved the pattern quality of the inkjet printed circuit, which are further improved upon heating of substrate. On the other hand, there is little effect on the adhesion, which is improved only by a special primer coating. The adhesion of inkjet printed circuit has been increased more than 10 times upon treatment. As for the screen printed circuits, the overall effects are less significant since there is some organic binder in the ink. Nonetheless, the treatment has strong positive effects on pattern quality and adhesion. The adhesion of 1 kgf/cm2, which is comparable with those of the conventional PCB circuits, is possible through primer coating for both screen and inkjet printed circuits. The resulting circuit also showed good thermal, mechanical and electrical properties.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권5호
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• pp.713-718
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• 2016

Predicting precise specifications of differential mixed-signal circuits is a difficult problem, because analytically derived correlation between process variations and conventional specifications exhibits the limited prediction accuracy due to the phase unbalance, for most self-tests. This paper proposes an efficient prediction technique to provide accurate specifications of differential mixed-signal circuits in a system-on-chip (SoC) based on a nonlinear statistical nonlinear regression technique. A spectrally pure sinusoidal signal is applied to a differential DUT, and its output is fed into another differential DUT through a weighting circuitry in the loopback configuration. The weighting circuitry, which is employed from the previous work [3], efficiently produces different weights on the harmonics of the loopback responses, i.e., the signatures. The correlation models, which map the signatures to the conventional specifications, are built based on the statistical nonlinear regression technique, in order to predict accurate nonlinearities of individual DUTs. In production testing, once the efficient signatures are measured, and plugged into the obtained correlation models, the harmonic coefficients of DUTs are readily identified. This work provides a practical test solution to overcome the serious test issue of differential mixed-signal circuits; the low accuracy of analytically derived model is much lower by the errors from the unbalance. Hardware measurement results showed less than 1.0 dB of the prediction error, validating that this approach can be used as production test.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.82-82
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• 2008

One-dimensional (1D) nanowires have been received much attention due to their potential for applications in various field. Recently some logic applications fabricated on various nanowires, such as ZnO, CdS, Si, are reported. These logic circuits, which consist of two- or three field effect transistors(FETs), are basic components of computation machine such as central process unit (CPU). FETs fabricated on nanowire generally have surrounded shapes of gate structure, which improve the device performance. Highly integrated circuits can also be achieved by fabricating on nano-scaled nanowires. But the numerical and SPICE simulation about the logic circuitry have never been reported and analyses of detailed parameters related to performance, such as channel doping, gate shapes, souce/drain contact and etc., were strongly needed. In our study, NAND and NOT logic circuits were simulated and characterized using 2- and 3-dimensional numerical simulation (SILVACO ATLAS) and built-in spice module(mixed mode).

• 대한전자공학회논문지SD
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• 제42권2호
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• pp.15-22
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• 2005

System-on-Glass 아날로그 회로를 구현하기 위해 요구되는 저항 matching 및 poly-Si TFT 특성을 기존 아날로그 회로를 이용하여 조사하였다. 저항 값, poly-Si TFT의 문턱전압 및 이동도의 matching 조건을 디스플레이 시스템의 해상도에 따라 유도하였다. 또한, 소스 드라이버를 구현하기 위해 요구되는 poly-Si TFT의 유효 이동도를 다양한 패널 크기에 따라서 분석하였다.

• 전자공학회논문지A
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• 제33A권2호
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• pp.173-183
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• 1996

In this paper, a new structure that can do fault detection and location of digial logic circuits more efficiently using current testing techniques is proposed. In the conventional method, observation point for steady state power supply current was only one, but in the proposed method more fault classes are divided for fault detection and location through the ovservation of steady state power supply current at two points. Also, it is shown that this structure can be easily applied in detection of stuck-open fault which is not easy to do testing with conventional current testing techniques. In the presented mehtod, an extra trasnistor is used, and current path is made compulsorily in the CMOS circuits in which no current path can be established in steady state, then it can be known that stuck-open tault is in the MOS transistor on the considering current path, if this path disappears due to stuck-open fault. The validity and the effectiveness is shwon, thorugh the SPICE simulation of circuits with fault and the current path search experiment using current path search program based on transistor short model wirtten in C language on SUN sparc workstation.

• Molecules and Cells
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• 제40권6호
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• pp.379-385
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• 2017

Drug addiction is a severe psychiatric disorder characterized by the compulsive pursuit of drugs of abuse despite potential adverse consequences. Although several decades of studies have revealed that psychostimulant use can result in extensive alterations of neural circuits and physiology, no effective therapeutic strategies or medicines for drug addiction currently exist. Changes in neuronal connectivity and regulation occurring after repeated drug exposure contribute to addiction-like behaviors in animal models. Among the involved brain areas, including those of the reward system, the striatum is the major area of convergence for glutamate, GABA, and dopamine transmission, and this brain region potentially determines stereotyped behaviors. Although the physiological consequences of striatal neurons after drug exposure have been relatively well documented, it remains to be clarified how changes in striatal connectivity underlie and modulate the expression of addiction-like behaviors. Understanding how striatal circuits contribute to addiction-like behaviors may lead to the development of strategies that successfully attenuate drug-induced behavioral changes. In this review, we summarize the results of recent studies that have examined striatal circuitry and pathway-specific alterations leading to addiction-like behaviors to provide an updated framework for future investigations.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1131-1134
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• 2003

Unknown parameters of a nonlinear system were estimated using a signal compression method. The estimated parameters were natural frequency and tile damping coefficient. This study applied a algorithm using tile comparison of the cross-correlation coefficient between the impulse response from a model and it from the signal compression method. The impulse through linear element included in a nonlinear system could be obtained by the signal compression method. The unknown parameters of the linear element could be estimated by comparing the Bode plots of system's impulse response with them of model's response. In this study, a LSCM(LabVIEW-Signal-Compression-Method) was developed to identify a nonlinear system. The LSCM consisted of National Instrument's (NI) Data Acquisition (DAQ) Board (Model PCI-1200), a monitoring program using LabVIEW software package, DAQ Signal Accessory Board, and 2nd-order electric circuits. The designed electric circuits consisted of resistors, inductors and capacitors. To evaluate the performance of the LSCM, the response from model with known parameters is compared with the response from the real system using the monitoring program. The results from simulation of experiment showed that the developed LSCM provided a reliable estimation performance.

• 제어로봇시스템학회논문지
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• 제3권1호
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• pp.101-108
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• 1997

The initial token value required to the optimal performance of discrete event systems can be decided by Sum of Delay Time and Synchronic Time ratio, which are new synchronic variables in Timed Place Petri Nets. For the system consisting of two Live-and-Bounded circuits(LB-circuits) fused in common Transition-Transition-Path or common Place-Place-Path, we prove that the Synchronic Time Ratio is the initial token ratio between two LB-circuits to optimally perform system functions. These results are generalized and formulated as a theorem. The initial tokens of a specific place can imply shared resources. Using the theorem, we can decide the minimum number of the shared resources to obtain the optimal performance, and minimize the idling time of resources. As an example, an automated assembly system is modeled by Timed Place Petri Net, and the initial tokens to achieve the optimal system performance are identified. All the values are verified by simulation.

• 설비공학논문집
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• 제22권5호
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• pp.259-267
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• 2010

An experiment has been performed in order to investigate the characteristics of multiple thermoelectric modules (TEMs) with electrical circuits. The open circuit voltage of TEM connected parallel circuit is equal to the sum of individual TEMs. In contrast, the open circuit voltage is equal to the average of that individual TEM for a series circuit. The power output and conversion efficiency of TEM for both parallel and series circuits increase as the operating temperature conditions for individual TEMs becomes identical. Comparing parallel with series circuits, the power generation performance is more excellent for series circuit than parallel circuit. This result is attributed to the power loss from the TEM with better power generation performance.