• Journal of IKEEE
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• v.13 no.3
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• pp.1-6
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• 2009

In this paper, the external matching circuits were designed in order to compensate the efficiency which decreases by human body effect in the internal antenna phone. Comparing the two types of matching circuit, we selected the structure to minimize the switch stress. RF MEMS switch using low voltage was compared with FET switch and measured the performance in the handset. Here, the detection circuit which can couple th reflection power from antenna was added in the handset and we set up the demonstration system that can compensate the loss of hand effect automatically. In this system, when hand effect occurred, the radiation power increased 2.5dB by operation the matching circuit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.155-159
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• 2004

This paper describes the design and the simulation of a single pole double throw(SPDT) FET switch for wireless LAN(IEEE802.11a ＆ IEEE802.11b) applications using drain impedance transformation network with Microstrip transmission line. At the receiving path insertion losses were from 0.8(㏈) to 1.462(㏈) between 2(㎓) and 4(㎓), from l.26(㏈) to 2.3(㏈) between 4.7(㎓) and 6.7(㎓) and the isolations were under 30(㏈) between 2(㎓) and 6.7(㎓). At the transmitting path insertion loss were from 1.18(㏈) to 2.87(㏈) between 2(㎓) and 4(㎓) from 0.625(㏈) to 1.2(㏈) between 4.7(㎓) and 6.7(㎓) and the isolations were under 30(㏈) between 2(㎓) and 6.7(㎓).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.88-96
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• 2016

In this paper, the GaN FET based phase-shift full-bridge dc-dc converter design is implemented. Switch characteristics of GaN FET were analyzed in detail by comparing state-of-the-art Si MOSFET. Owing to the low conduction resistance and parasitic capacitance, it is expected to GaN FET based power conversion system has improved performance. However, GaN FET is vulnerable to electric interference due to the relatively low threshold voltage and fast switching transient. Therefore, it is necessary to consider PCB layout to design GaN FET based power system because PCB layout is the main reason of stray inductance. To reduce the electric noise, gate voltage of GaN FET is analyzed according to operation mode of phase-shift full-bridge dc-dc converter. Two 600W phase-shifted full-bridge dc-dc converter are designed based on the result to evaluate effects of stray inductance.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.310-313
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• 2005

In this paper, four quadrant CBPS(Compact Bipolar Power Supply) which development and study using universal PWM controller. The CBPS has 24V DC-link voltage, +/-5A output current, 50kHz switching frequency and 30Hz full load bandwidth using FET device. Proposed system has two independent PWM controllers for each full-bridge switch leg drive and PI control loops for current regulations. It is shown experimental results that good step response of the current output.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.89-90
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• 2014

Recently, one of the switching rectifiers, Power Factor Correction Circuit is often applied in rectification stage to get high efficient conversion of AC-DC SMPS However, it becomes important to select optimal semiconductor switch as well as to design optimal rectifier for achieving higher power conversion. We performed experiments with MOSFET, SiC and GaN FET that are widely used in 600 W Interleaved CRM PFC and include the data in this report. The results are presented for discrete semiconductor and integrated implementations of interleaved CRM PFC.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.332-333
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• 2019

본 논문에서는 전기자동차용 단상 양방향 온보드 충전기를 위한 Cycloconverter-type high frequency link 컨버터에 Si-IGBT와 SiC-FET을 적용하여 전력반도체의 전력 손실을 예측하고 비교하고 분석한다. 와이드밴드갭 전력반도체 중 하나인 SiC-FET은 기존 Si기반의 IGBT를 대신하여 사용될 전력반도체로써 각광 받고 있다. 또한, 낮은 온-저항으로 인해 적은 전력손실과 고주파 스위칭을 통한 직류단 필터의 크기감소를 통해 높은 전력밀도를 달성할 수 있다. 이에 Si-IGBT와 SiC-FET을 Cycloconverter-type high frequency link 컨버터에 적용하여 전력손실을 PSIM thermal module을 통해 시뮬레이션하고 비교 분석한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.652-655
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• 2004

RF MEMS is a miniature device or an array of integration devices and mechanical components and fabricated with If batch-processing techniques. RF MEMS application area are in phased arrays and reconfigurable apertures for defence and telecommunication systems, switching network for satellite communication, and single-pole double throw switches for wireless application. Recently, RF MEMS switches have been developed for the application to the milimeter wave system. RF MEMS switches offer a substantilly higher performance than PM diode or FET switches. In this paper, SPDT(single-pole-double-throw) switch are designed to use 10 GHz. Actuation voltage and displacement are simulated by tool. And stress and distribution are simulated.

• Journal of Digital Contents Society
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• v.10 no.2
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• pp.199-207
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• 2009

The Q-switching the shutter or the different optical science element puts in within the laser light resonator and the storehouse departs from the within the resonator it loses the mortar and the reversal distribution which when is sufficient creates from within the active medium, opens the shutter instantaneously and it is to do to be made to emit with the light where the energy which is accumulated within the resonator is strong very. Like this Q-switching of laser resonator--It decreases factor increasing suddenly to make. To method of Laser Q-switching mechanical switching methods, electro-optic switching methods and switching by saturable absorber methods, acousto-optic switching method etc. 4 kind are being used on a large scale. In these people the conversion which is electric in compliance with the effect which is electrooptics is widely being used the Q-switching pulse of short pulse width because being it will be able to create. Consequently, Pockel cell where it has the quality of electrooptics effect) the Q-it is become known that it is suitable it uses with switch. From the research which it sees FET and one-chip microprocessor where it is a switching element and pulse transfomer to plan and produce pockel cell Q-switch driving gears, pulse style Nd: It applied in YAG Laser system and it investigated and researched the operating characteristic of the Q-switch. Also, the Q-switch leads and Nd where it is output: YAG with forecast in compliance with a theoretical calculation it comes to buy laser beam side politics it compared and laser beam qualities which had become Q-switching it analyzed.

• Journal of Power Electronics
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• v.18 no.6
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• pp.1912-1919
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• 2018

The output capacitance of power semiconductor devices is important in determining the switching losses and in the operation of some resonant converter topologies. Thus, it is important to be able to accurately determine the output capacitance of a particular device operating at elevated power levels so that the contribution of the output capacitance discharge to switch-on losses can be determined under these conditions. Power semiconductor switch manufacturers usually measure device output capacitance using small-signal methods that may be insufficient for power switching applications. This paper shows how first principle methods are applied in a novel way to obtain more relevant large signal output capacitances of Gallium-Nitride (GaN) FETs using the drain-source voltage transient during device switch-off numerically. A non-linear capacitance for an increase in voltage is determined with good correlation. Simulations are verified using experimental results from two different devices. It is shown that the large signal output capacitance as a function of the drain-source voltage is higher than the small signal values published in the data sheets for each of the devices. It can also be seen that the loss contribution of the output capacitance discharging in the channel during switch-on correlates well with other methods proposed in the literature, which confirms that the proposed method has merit.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.300-301
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• 2018

본 논문에서는 인덕션 쿠커의 스위칭 전력반도체에서 발생되는 스위치 손실을 비교 분석한다. Si-기반 전력반도체의 효율 상승이 한계점에 도달함에 따라 고속 스위칭 및 저손실 특성을 지닌 SiC, GaN와 같은 와이드밴드갭 소자를 활용한 고전력밀도 컨버터의 연구가 활발히 진행되고 있다. 이에 소비자 가전분야의 인덕션쿠커 공진형 하프-브릿지 전력회로의 기존 Si-IGBT를 GaN-FET과 SiC-FET으로 구성하여 스위치 손실모델을 유도하고 이를 통해 세 가지의 전력반도체가 적용된 인덕션 쿠커의 스위치 손실을 비교분석한다. 분석된 손실모델은 PSIM Thermal Module을 통하여 검증한다.