• Journal of Power Electronics
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• v.17 no.6
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• pp.1454-1468
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• 2017

In this study, a new dual-active soft-switching converter is proposed to improve conversion efficiency and extend the load range for an MTEM electromagnetic transmitter in geological exploration. Unlike a conventional DC/DC converter, the proposed converter can operate in passive soft-switching, single-active soft-switching, or dual-active soft-switching modes depending on the change in load power. The main switches and lagging auxiliary switches of the converter can attain soft-switching over the entire load range. The conduction and switching losses are greatly reduced compared with those of ordinary converters under the action of the cut-off diodes and auxiliary windings coupled to the main transformer in the auxiliary circuits. The conversion efficiency of the proposed converter is significantly improved, especially under light-load conditions. First, the working principle of the proposed converter is analyzed in detail. Second, the relationship between the different operating modes and the load power is given and the design principle of the auxiliary circuit is presented. Finally, the Saber simulation and experimental results verify the feasibility and validity of the converter and a 50 kW prototype is implemented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.277-280
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• 2005

This paper dealt with the development of a surge protection device (SPD) that can protect high speed computer network devices from overvoltages caused by switching operations or lightning surges. The designed SPD is a form of hybrid circuit which is composed of a gas tube having large current diverting capability, high response bi-directional avalanche diodes, and fast recovery diodes to reduce insertion loss on high frequency domain. Surge protection and signal transmission characteristics of the fabricated SPD was tested according to the international standards, IEC 61000-4-5 and IEC 61643-21. From the test results, the SPD is satisfied with the international standards and the high cut-off frequency was 204MHz. Also, the SPD showed a good performance without an insertion loss on a field test of 100Mbps class Local Area Network

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.381-386
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• 2013

A new resistance model for a Schottky Barrier Diode (SBD) in CMOS technology is proposed in this paper. The proposed model includes the n-well thickness as a variable to explain the operational behavior of a planar SBD which is firstly introduced in this paper. The model is verified using the simulation methodology ATLAS. For verification of the analyzed model and the ATLAS simulation results, SBD prototypes are fabricated using a $0.13{\mu}m$ CMOS process. It is demonstrated that the model and simulation results are consistent with measurement results of fabricated SBD.

• Applied Science and Convergence Technology
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• v.24 no.2
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• pp.41-46
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• 2015

Transparent conductive oxides (TCOs) are essential material in optoelectronics such as solar cells, touch screens and light emitting diodes. Particularly TCOs are attractive material for infrared cut off film due to their high transparency in the visible wavelength range and high infrared reflectivity. Among the TCO, Indium tin oxide has been widely used because of the high electrical conductivity and transparency in the visible wavelength region. But ITO has several limitations; expensive and low environmental stability. On the other hands, fluorine doped tin oxide (FTO) is well known for low cost, weather ability and stable in acidic and hydrogen. In this study, two different magnetron sputtering techniques with RF and DC modes at room temperature deposition of FTO thin film was conducted. The change of oxygen content is influence on the topography, transmittance and refractive index.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.6
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• pp.1253-1259
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• 2005

This paper dealt with the development of surge protection devices (SPDs) that can protect high speed computer network devices from overvoltages caused by switching operations or lightning surges. The designed SPD is a form of hybrid circuit which is composed of a gas tube having large current diverting capability, high response bi-directional avalanche diodes, and fast recovery diodes to reduce insertion loss on high frequency domain. Surge protection and signal transmission characteristics of the fabricated SPD was tested according to the international standards, IEC 61000-4-5 and IEC 61643-21. From the test results, the SPD is satisfied with the international standards and the high cut-off frequency was 204 MHz. Also, the SPD showed a good performance without an insertion loss on a field test of 100 Mbps class Local Area Network.

• Journal of the Korean Institute of Telematics and Electronics
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• v.7 no.2
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• pp.33-42
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• 1970

This report is concerned with the fahrication with the falricationof silicon VVC diode by the double diffusion planer technique. At first, some design charts for VVC diode were derived by considering the voltage-capacitance relations, the critical field intensity at the metallurgical junction, and the cut-off frequency of the diode. These charts enables the fabrication engineers to design VVC diode easily without going into the sophisticated design theory. We started with a 2.5 ohm-cm n-type epitaxial silicon wafer. The phosphorous was diffused by POCl3 impurity source. Then boron diffusion followed make hyperabrupt p-n junction by BN source. The maximum to minimum capacitance ratio of the diode as a tuning diode for a TV tuner made in these experiments was 4:1. Measured electrical characteristics of the sample diodes showed in good agreement with the theoretical expectations. Slicing and polishing technique of the silicon wafer and diffusion technique of the impurity atoms, which were employed in our study, are also stated briefly in this report.

• Journal of Fashion Business
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• v.25 no.1
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• pp.51-64
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• 2021

The purpose of this study was to develop smart bags that combining fashion-specific trends and smart information technologies such as light-emitting diodes(LED) and optic fibers by grafting marquage techniques that have recently become popular as part of eco-fashion. We applied e-textiles by designing leather tote bags that could show off LED luminescence. A total of two tote bags, a white-colored peacock design and a black-colored paisley design, divided the LED's light-emitting method into two types, incremental lighting and random light-emission to suit each design, and the locations of the optical fibers were also reversed depending upon the design. The production of circuits for the LEDs and optical fibers was based on the design, and a flexible conductive fabric was laser-cut instead of wire line and attached to the circuit-line location. A separate connector was underwent three-dimensional(3D)-modeling and was connected to high-luminosity LEDs and optic fiber bundles. The optical fiber logo part expressed a subtle image using a white-colored LED, which did not offset the LED's sharp luminous effects, suggesting that using LEDs with fiber optics allowed for the expression of each in harmony without being heterogeneous. Overall, the LEDs and fiber optic fabric were well-harmonized in the fashion bag using marquage techniques, and there was no sense of it being a mechanical device. Also, the circuit part was made of conductive fabric, which is an e-textile product that feels the same as a thin, flexible fabric. The study confirmed that the bag was developed as a smart wearable product that could be used in everyday life.

• Journal of Sensor Science and Technology
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• v.12 no.2
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• pp.66-71
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• 2003

Pt/AlGaN Schottky-type UV photodetectors were designed and fabricated. A low-temperature AlGaN interlayer buffer was grown between the AlGaN and GaN film in the diode structure epitaxy to obtain crack-free AlGaN active layers. A comparison was then made of the structural, electrical, and optical characteristics of two different diodes: one with an AlGaN($0.5\;{\mu}m$)/n+-GaN(2 nm) structure (type 1) and the other with an AlGaN($0.5\;{\mu}m$)/AlGaN interlayer($150\;{\AA}$)/n+-GaN($3\;{\mu}m$) structure(type 2). A crack-free AlGaN film was obtained by the insertion of a low-temperature AlGaN interlayer with an aluminum mole fraction of 26% into the $Al_xGa_{1-x}N$ layer. The fabricated Pt/$Al_{0.33}Ga_{0.67}N$ photodetector had a leakage current of 1 nA for the type 1 diode and $0.1\;{\mu}A$ for the type 2 diode at a reverse bias of -5 V. For the photoresponse measurement, the type 2 diode exhibited a cut-off wavelength of 300 nm, prominent responsivity of 0.15 A/W at 280 nm, and UV-visible extinction ratio of $1.5{\times}10^4$. Accordingly, the Pt/$Al_{0.33}Ga_{0.67}N$ Schottky-type ultraviolet photodetector with an AlGaN interlayer exhibited superior electrical and optical characteristics and improved UV detecting properties.