• Proceedings of the KIEE Conference
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• 1979.08a
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• pp.138-141
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• 1979

The purpose of this paper is to develop an efficient model for the analysis of a John's Chopper Circuit. In the John's Chopper Circuit analysis, the open branches are removed from the associated graph to formulate the modified incidence matrix. An algorithm for the generation of a modified proper tree and fundamental cut set matrix from a network graph is developed, which utilizes much less computer storage space and computation time compared to the classical methods.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.334-336
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• 2002

This study is concerned with the operation algorithm and power switch drive circuit for DC Reactor Type High-Tc Superconducting Fault Current Limiter (SFCL). In the case of SFCL, Power switching operation algorithm are very important problem. So, this driving will determine the performance of SFCL. In this paper, we provide a simple algorithm and easy drive circuit. Through experiment we found that ideal is right.

• Electrical & Electronic Materials
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• v.9 no.5
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• pp.506-511
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• 1996

This paper deals with an inexpensive, simple and fast Langmuir probe sweeping circuit and its application. This sweeper completes a probe trace in a 1 ms order. Futhermore, the circuit drives a maximum probe voltage of $\pm$30V and has a maximum probe current capability of a few amperes. The plasma parameters are successfully determined using the fast Langmuir probe method.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1093-1096
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• 2008

The circuit simulation has been done on the current-programmed AMOLED and shows that the circuit which behaves as a negative capacitance can reduce the effect of parasitic capacitance fixed on the data-line and can accelerate the current programming speed as high as that required in Full HD AMOLED.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.46.4-46
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• 2001

This paper presents a Five-Switch Converter (FSC) circuit that can operate like a full-bridge PWM converter for driving the DC motor in bidirectional. One of the main advantages of this circuit is to reduce the on-off switching number of power MOSFET. In stead of turning on-off simultaneously two of the four power MOSFET´s in a switching period, this circuit operates only one power MOSFET, while continuously leaving another two on and the other two off in the switching period. Consequently ...

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.323-327
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• 1998

Under high power IGBTs Switching, a large overvoltage is induced across the IGBT module due to the stray inductance in the circuit. This paper proposes a new gate drive circuit for high power IGBTs which can actively suppress the overvoltage across the driven IGBT at turn-off while preserving the most simple and reliable power circuit. The turn-off driving scheme has adaptive feature to the amplitude of collector current, so that the overvoltage can be limited much effectively at the fault collector current. Experimental results under various normal and fault conditions prove the effectiveness of the proposed.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.36-38
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• 2002

Low voltage circuit breakers which interrupt rapidly and raise the reliability of power supply are widly used in power distribution systems. In the paper, it was investigated how much Interrupting capability was improved by correcting the shape of the contact system in molded case circuit breaker(below MCCB), Prior to the interrupting testing, it was necessary for the optimum design to analyze magnetic forces on the contact system, generated by current and flux density. This paper presents both our compuational analysis and test results contact system in MCCB.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.474-480
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• 2003

We designed and tested a new scan driver output stage. Compared to conventional CMOS structured scan driver IC′s, the new NMOSFET-only scan driver circuit can reduce the chip area and therefore, the chip cost considerably. We confirmed the circuit operation with open drain power NMOSFET IC′s by driving 2"PDP test panel. We defined critical device parameters and their optimization methods lot the best circuit performance.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.3
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• pp.223-231
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• 2015

LEDs have been widely used in lighting displays, automobiles, and airplanes owing to their excellent light output characteristics and long lifespan. Though LEDs are manufactured under the same process, variations in impurity concentrations cause electrical deviation among LEDs. The resulting electrical deviation can not only reduce the life time of the LED but also cause non-uniform luminance of LEDs connected in parallel. LED driving circuit is required to solve these problems. In this paper, we propose a LED driving system using Y-type current balancing transformer to maximize the efficiency of the system by removing output stage Schottky diodes. Experimental results are presented to verify the performance of proposed LED driving system that is applied to 80 W LED modules.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1418-1421
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• 2003

The Vacuum circuit breaker is a kind of power circuit breaker and protect electric devices from over-current. In this paper we built a dynamic model of VCB driving mechanism using ADAMS. The development of the new circuit breaker with less energy and more compactable mechanism is focused. Through the dynamic model, the concept design of the new circuit breaker with less energy and more compactable mechanism is proposed, and then the detailed design is carried out through the design process based on the dynamic model.