• Proceedings of the KIEE Conference
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• summer
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• pp.443-445
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• 2004

본 논문에서는 22.9kV급 Shunt Capacitor Bank 내부 고장으로 인한 불평형 요소를 검출하기 위하여 기존의 차동전압의 크기만을 이용한 보호 방식을 검토하고, 이 보호 방식에서 발생되는 여러 문제점들을 해결하기 위한 개선 방안을 제안한다. 기존의 차동전압의 크기를 이용한 보호 방식에서는 인입단 근처에서의 고저항 아크 고장이나 접지단 근처에서의 지락 고장 등에 의해 Capacitor 소자에 손상을 입을 수 있지만, 이에 대한 고장 판정이 용이하지 않다. 따라서 이를 해결하기 위하여 본 논문에서는 차동전압의 주파수 계전 방식 및 접지단 전압 등을 도입하였다. 특히, 주파수 계전 요소를 도입할 경우에 비선형 부하 둥으로부터 발생되는 고조파의 영향이 없다는 것을 입증하여 부하의 종류와는 무관하게 본 논문에서 제안한 방법이 적용될 수 있음을 보였다 본 논문에서 제안한 알고리즘은 사례 연구를 통하여 그 타당성이 입증되었다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.113-118
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• 2005

This paper shows a satellite battery cell voltage monitor system to make differential voltage measurements when one or both measurement points are beyond voltage range allowed by a conventional differential amplifier. This system is particularly useful for monitoring the individual cell voltage of series-connected cells that constitute a rechargeable satellite battery in which some cell voltages must be measured in the presence of high common mode voltage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.891-896
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• 2011

This paper describes the differential voltage-to-frequency converter which is realized current conveyor circuits. The output frequency of the differential voltage-to-frequency converter is proportional to the difference of two input voltages. The designed circuit is simulated by HSPICE. The range of input voltage difference is from several volts to several milli-volts. From the simulation results the error is less than from -1.9% to +1.8% compared to the calculated values.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.293-294
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• 2016

태양광 발전 시스템은 그 필요성이 늘어남에 따라 다양한 연구가 진행되고 있다. 기존에 태양광 발전 제어 방식인 스트링 방식이나, 마이크로 컨버터 같은 방식 이외에도 그늘짐 등으로 인해 발생한 태양광 모듈의 전력 차이만을 부담하는 컨버터를 이용한 차동 전력 조절 방식도 연구가 되고 있다. 차동 전력조절기는 담당하는 전력이 적고, 스트링 컨버터를 통해 많은 전력이 전달이 되어 기존의 방식 보다 효율이 높다. 하지만, 태양광 모듈 MPPT 전압으로 부터 DC_link 전압만큼의 승압이 필요하다. 따라서, 고승압, 고효율 컨버터를 차동 전력 조절기로 사용을 하면 기존의 차동 전력 방식보다 더 나은 동작 특성을 가질 수 있다. 따라서 본 논문에서는 차동 전력 조절기로 고승압의 컨버터 토폴로지를 사용하여, 기존의 방식보다 고효율을 유지하면서 차동 전력 조절기의 기능을 수행하는 구조를 제안한다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.6 s.360
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• pp.60-68
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• 2007

A technique is presented to extract differential second harmonic output from common source nodes of a cross-coupled P-& N-FET oscillator. Provided the impedances at the common source nodes are optimized and the fundamental swing at the VCO core stays in a proper mode, it is found that the amplitude and phase errors can be kept within $0{\sim}1.6dB$ and $+2.2^{\circ}{\sim}-5.6^{\circ}$, respectively, over all process/temperature/voltage corners. Moreover, an impedance-tuning circuit is proposed to compensate any unexpectedly high errors on the differential signal output. A Prototype 5-GHz VCO with a 2.5-Hz LC resonator is implemented in $0.18-{\mu}m$ CMOS. The error signal between the differential outputs has been measured to be as low as -70 dBm with the aid of the tuning circuit. It implies the push-push outputs are satisfactorily differential with the amplitude and phase errors well less than 0.34 dB and $1^{\circ}$, respectively.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.46-47
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• 2015

본 논문은 태양광 발전 시스템의 차동 전력 조절 방식 중 Feed-Foward 방식을 적용한 다중 출력 플라이백 컨버터를 이용하여 DC_Link 다중 출력 전압을 균등화 하는 회로에 대한 내용이다. DC_Link가 여러 단으로 되어 있을 경우, 전압을 일정하게 맞추어 줄 필요가 있는데, 이를 차동 전력 조절기(Differential Power Processing converter)를 통해서 DC_Link 출력 전압을 균등화 할 수 있다. 스트링 컨버터인 부스트 컨버터의 스트링 전류를 제어 하여 부스트 컨버터의 전력과 DPP역할을 하는 다중 출력 플라이백 컨버터로 전달되는 전력을 조정가능하다. 이를 통하여 전압 균등화가 이루어지게 할 수 있고, 각 DPP 컨버터는 PV 전압 제어를 하여 MPPT 동작을 하게 된다. PSIM 시뮬레이션과 150W급 하드웨어 프로토타입을 제작해 실험을 통하여 검증 하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.10
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• pp.70-78
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• 2009

This paper addresses the analysis and the design optimization of differential interconnects for high-speed Low-Voltage Differential Signaling (LVDS) applications. Thanks to the differential transmission and the low voltage swing, LVDS offers high data rates and improved noise immunity with significantly reduced power consumption in data communications, high-resolution display, and flat panel display. We present an improved model and new equations to reduce impedance mismatch and signal degradation in cascaded interconnects using optimization of interconnect design parameters such as trace width, trace height and trace space in differential printed circuit board (FPCB) transmission lines. We have carried out frequency-domain full-wave electromagnetic simulations, and time-domain transient simulations to evaluate the high-frequency characteristics of the differential FPCB interconnects. We believe that the proposed approach is very helpful to optimize high-speed differential FPCB interconnects for LVDS applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.8
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• pp.867-880
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• 1992

In this paper, a circuit design techniques for Improving the voltage gain of the GaAs MESFET single amplifier is presented. Also, various types of existing current mirror and proposed current mirror of new configuration are compared. To obtain the high differential mode gain and low common mode gain, bootstrap gain enhancement technique Is used and common mode feedback Is employed In the design of differential amplifier. The simulation results show that designed differential amplifier has differential gain of 57.66dB, unity gain frequency of 23.25GHz. Also, differential amplifier using common mode feedback with alternative negative current mirror has CMRR of 83.S8dB, stew rate of 3500 V /\ulcorners.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.761-764
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• 2007

This paper addresses the analysis and the design optimization of differential interconnects for Low-Voltage Differential Signaling (LVDS) applications. Thanks to the differential transmission and the low voltage swing, LVDS offers high data rates and improved noise immunity with significantly reduced power consumption in data communications, high-resolution display, and flat panel display. We present an improved model and new equations to reduce impedance mismatch and signal degradation in cascaded interconnects using optimization of interconnect design parameters such as trace width, trace height and πace space in differential flexible printed circuit board (FPCB) transmission lines. We have carried out frequency-domain full-wave electromagnetic simulations, time-domain transient simulations, and S-parameter simulations to evaluate the high-frequency characteristics of the differential FPCB interconnects.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.336-342
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• 2003

In this paper, a new differential detector is introduced, in which a solar cell is used to reduce the low frequency interference from environmental optical noise. The solar cell also supplies electrical power to the detector circuit using the optical noise power. The DC voltage from the solar cell is used as a power supply to the detector, and the AC voltage is used to reduce the optical noise in a photodiode with the differential detection method. The signal to noise ratio was improved by about 20 dB.