• 한국전자파학회논문지
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• 제28권10호
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• pp.832-835
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• 2017

본 논문은 고속 무선 데이터 통신을 위한 V-band 차동 저잡음 증폭기를 65-nm CMOS 공정을 이용하여 설계한 결과를 제시한다. 설계한 저잡음 증폭기는 3단 공통소스 구조이며, MOS 커패시터를 이용한 커패시턴스 중화 기법을 적용하였고, 트랜스포머를 이용하여 각 단의 임피던스 정합을 구현하였다. 제작한 저잡음 증폭기는 63 GHz에서 최대 이득 23 dB을 보이며, 3 dB 대역폭은 6 GHz이다. 제작한 칩의 크기는 패드를 포함하여 $0.3mm^2$이며, 1.2 V 공급 전원에서 32 mW의 전력을 소비한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기설비전문위원
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• pp.77-79
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• 2004

It is caused that insulation paper, which had got a lot of thermal stress by over-load after installation, should have been deteriorated in electrical and mechanical characteristics. Beside, insulation material is decreased the insulating property and accelerated aging of them in case of dielectric loss when transformers are manufactured with some moisture or transformers would have been them because of moisture-permeation. Therefore, in this study we experienced the influence of moisture content in case of the thermal aged insulation paper. we have measured tan 6 and breakdown voltage in the ratio of paper' moisture content before the aging and then taken the same tests again after insulation paper thermally accelerating-aged. There is a purpose to gain data for a life-design and to establish aging mechanism in order to continuously study life expectancy of the insulation paper

• 전기학회논문지
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• 제65권6호
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• pp.1108-1114
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• 2016

The cause of failure in the AT feeding system is divided into grounding, short-circuit of feeding circuit and internal faults of the railway substation. Since the fault current is very high, real-time current is detected and the failure must be immediately removed. In this paper, a new DC offset elimination filter that can remove component to decrease in the form of exponential function using low-pass filter was proposed in order to extract the fundamental wave from distorted fault current. In order to confirm the performance of the proposed filter method, AT feeder system was modelled by simulation tool and simulations were performed under various conditions such as fault location, fault resistance and fault voltage phase angle in case of trolley-rail short-circuit fault. When applying the proposed DC-offset removal method, it can be seen that the phase delay and gain error did not appear.

• Journal of Power Electronics
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• 제9권2호
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• pp.215-223
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• 2009

A design methodology for transformers including integrated and center-tapped structures for LLC resonant converters is proposed. In the LLC resonant converter, the resonant inductor in the primary side can be merged in the transformer as a leakage inductance. And, the absence of the secondary filter inductor creates low voltage stress on the secondary rectifiers and is cost-effective. A center-tapped structure of the transformer secondary side is widely used in commercial applications because of its higher efficiency and lower cost than full-bridge structures in the rectifying stages. However, this transformer structure has problems of resonance imbalance and transformer inefficiency caused by leakage inductance imbalance in the secondary side and the position of the air-gap in the transformer, respectively. In this paper, gain curves and soft-switching conditions are derived by first harmonic approximation (FHA) and operating circuit simulation. In addition, the effects of the transformer including integrated and center-tapped structures are analyzed by new FHA models and simulations to obtain an optimal design. Finally, the effects of the air-gap position are analyzed by an electromagnetic field simulator. The proposed analysis and design are verified by experimental results with a 385W LLC resonant converter.

• 센서학회지
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• 제26권5호
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• pp.342-347
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• 2017

We present a precision instrument amplifier (IA) designed for bio-potential acquisition. The proposed IA employs a capacitively coupled instrument amplifier (CCIA) structure to achieve a rail-to-rail input common-mode range and low gain error. A positive feedback loop is applied to boost the input impedance. Also, DC servo loop (DSL) with pseudo resistors is adopted to suppress electrode offset for bio-potential sensing. The proposed amplifier was designed in a $0.18{\mu}m$ CMOS technology with 1.8V supply voltage. Simulation results show the integrated noise of $1.276{\mu}Vrms$ in a frequency range from 0.01 Hz to 1 KHz, 65dB SNR, 118dB CMRR, and $58M{\Omega}$ input impedance respectively. The total current of IA is $38{\mu}A$. It occupies $740{\mu}m$ by $1300{\mu}m$ including the passive on-chip low pass filter.

• 한국광학회지
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• 제4권3호
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• pp.294-300
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• 1993

표면광 마이크로 레잊, heterojunction phototransistor 그리고 저항을 단일 결정으로 성장시켜 집적시킨 NOR와 INVERTER 능동형 광 논리 소자에 대한 동작 특성을 조사하였다. 능동형 광 놀리 소자를 구성하는 개개 소자 중에서, 780 nm에서 발진하는 특정한 AlGaAs 초격자 마이크로 레이저의 미분 양자 효율은 15%로 나타났고, heterojunction phototransistor의 전류 이득은 에미터-컬렉터 전압이 4V이고, 입력 광의 세기가 $50{\mu}W$일 때 57으로 측정되었다. 직렬 저항이 370 ohm인 광 논리 소자의 출력은 입력광세기사 $47{\mu}W$일 때 $57{\mu}W$에서 $0{\mu}W$으로 감소하였다.

• 항공우주기술
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• 제3권1호
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• pp.251-256
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• 2004

적외선 소자로부터 생성되는 신호와의 비교에 의한 잡음 특성의 향상, 즉 좋은 영상을 얻기 위해서 적외선 영상신호 취득회로(ROIC)에서는 안정적인 기준 전압원이 필요하다. 본 논문은 극저온인 77K에서 동작하는 적외선 영상신호 취득회로(readout integrated circuit)를 위한 밴드갭 기준회로에 대해서 제안하고 있다. 기본에 발표된 대부분의 밴드갭 기준회로는 실온에서 동작하는 것이며, 액체질소 온도 77K에서 동작하는 적외선 영상 ROIC에는 적합하지 않다. 본 논문에서는 극저온에서 동작하는 밴드갭 기준회로 설계를 위하여, 온도변화에 따른 사용되는 소자들의 parameter에 대한 특성을 살펴본 후, 이러한 특성들을 고려하여 밴드갭 기준 회로를 제안하였으며 이것은 그 실용 가능성을 입증하고 있다.

• 한국전자파학회논문지
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• 제13권6호
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• pp.514-520
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• 2002

본 논문에서는 L-band용 이동통신 단말기에 적용 가능한 수신단 MMIC 믹서의 설계 및 제작에 관한 연구를 다룬다. 단일 칩으로 집적하기 적절한 LO 및 RF balun을 능동소자를 이용하여 구성하였으며 각 능동소자의 공정상의 변화를 보상하기 위하여 새롭게 제안된 바이어스 회로를 적용하였다. 믹서의 변환이득은 -14 dB이며 IP3는 약 4 dBm, 포트간 격리도는 25 dB 이상의 값을 가진다. 제안된 새로운 바이어스 회로는 FET와 저항으로 구성되며 공정상의 변화와 온도의 변화 등에 의한 문턱전압의 변화를 보상해 줄 수 있다. 설계된 칩의 사이즈는 1.4 mm$\times$1.4 mm이다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권3호
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• pp.144-148
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• 2001

For the purpose of developing capacitive humidity sensor having interdigit electrodes, interdigit electrode was modeled and simulated to obtain capacitance and sensitivity as a function of geometric parameters like the structural gap and thichness. For the development of ASIC, switched capacitor signal conditioning circuits for capacitive humidity sensor were designed and simulated by cadence using 0.25um CMOS process parameters. The signal conditioning circuits are composed of amplifier for voltage gain control, and clock generator for sensor driving and switch control The characteristics of the fabricated sensors are; 1) sensitivity is 9fF/%R.H., 2) temperature coefficient of offset(TCO) is 0.4%R.H./$^{\circ}C$, 3) nonlinearity is 1.2%FS, 4) hysteresis is 1.5%FS in humidity range of 3%R.H. ${\sim}$ 98%R.H.. The response time is 50 seconds in adsorption and 70 seconds in desorption. Fabricated process used in this capacitive humidity sensor having interdigit electrode are just as similar as conventional IC process technology. Therefore this can be easily mass produced with low cost, simple circuit and utilized in many applications for both industrial and environmental measurement and control system, such as monitoring system of environment, automobile, displayer, IC process room, and laboratory etc..

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 기술교육전문연구회
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• pp.8-11
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• 2003

We propose that when combustible burn with contain carbon, introduce fire detector with sensor of private-use detectable light energy as infrared and ultraviolet in energy of electromagnetic-wave type radiate from flame, method for correct discrimination to resemble fire produce false alarm of detector such as sun light, hot object radiation, are welding. This research using infrared sensor is pyroelectric infrared sensor based black body radiation theory. Ultraviolet sensor is uv Tron using gas multiplication effect to current discharge and photoelectric effect of metal. To have high sensibility and to gain proper output voltage, it has high responsive performance. This research introduced UV/IR compound type flame detector and proposed method of false alarm reduced to resemble fire. The result propres the prevention and extinction of fire technique degree, certificated operation of detector.