• 한국철도학회논문집
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• 제15권2호
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• pp.116-121
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• 2012

DC/DC스위칭 전력 컨버터는 임의의 직류전원을 부하가 요구하는 형태의 직류전원으로 변환시킨다. DC/DC 컨버터는 PWM-IC를 이용하여 주기적으로 입력측에서 출력측으로 전달되는 에너지를 제어하는 기능을 수행하는데, PWM-IC(펄스폭 변조-집적회로), MOSFET(산화물-반도체 전계 효과 트랜지스터), 인덕터, 콘덴서, 저항 등으로 구성되어 있다. 방사선의 영향으로 DC/DC 컨버터의 PWM-IC 를 구성하는 비교기(comparator)와 연산증폭기(OP-Amp.) 등 전자소자의 열화 효과(radiation effects)가 발생되는데, PWM-IC 동작에서 SPICE 시뮬레이션과 실험을 통해 펄스의 상실, 펄스폭의 변화, 그리고 출력파형의 변화를 연구하는데 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.403-406
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• 1987

CMOS operational amplifier is most useful building bloch in analog circuit. This paper represents the analysis and design method of CMOS OP AMP to use general purpose such as the A/D and D/A converter, PCM encoder and decoder etc. The required specifications is obtained by changing W/L ration of CMOS devices. The design procedure must be iterative in as much as it is almost impossible to relate all specifications simultaneously. This is performanced with IBM-PC XT by using SPICE(SIMULATION PROGRAM WITH INTEGRATED CIRCUIT EMPHASIS)program.

• International Journal of Aeronautical and Space Sciences
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• 제11권3호
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• pp.201-205
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• 2010

DC/DC Switching power converters are commonly used to generate regulated DC output voltages with high-power efficiencies from different DC input sources. A switching converter utilizes one or more energy storage elements such as capacitors, or transformers to efficiently transfer energy from the input to the output at periodic intervals. The fundamental boost converter studied here consists of a power metal-oxide semiconductor field effect transistor switch, an inductor, a capacitor, a diode, and a pulse-width modulation circuit with oscillator, amplifier, and comparator. A buck converter containing a switched-mode power supply is also studied. In this paper, the electrical characteristics of DC/DC power converters are simulated by simulation program with integrated circuit emphasis (SPICE). Furthermore, power efficiency was analyzed based on the specifications of each component.

• 센서학회지
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• 제14권2호
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• pp.96-100
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• 2005

The planar Schottky diodes were fabricated and modeled to probe the device applicability of the cracked GaN epitaxial layer on a (111) silicon substrate. On the unintentionally n-doped GaN grown on silicon, we deposited Ti/Al/Ni/Au as the ohmic metal and Pt as the Schottky metal. The ohmic contact achieved a minimum contact resistivity of $5.51{\times}10.5{\Omega}{\cdot}cm^{2}$ after annealing in an $N_{2}$ ambient at $700^{\circ}C$ for 30 sec. The fabricated Schottky diode exhibited the barrier height of 0.7 eV and the ideality factor was 2.4, which are significantly lower than those parameters of crack free one. But in photoresponse measurement, the diode showed the peak responsivity of 0.097 A/W at 300 nm, the cutoff at 360 nm, and UV/visible rejection ratio of about $10^{2}$. The SPICE(Simulation Program with Integrated Circuit Emphasis) simulation with a proposed model, which was composed with one Pt/GaN diode and three parasitic diodes, showed good agreement with the experiment.

• IEIE Transactions on Smart Processing and Computing
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• 제5권1호
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• pp.10-16
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• 2016

In this paper, a design for a fully digital voltage sensor using a 32-nm fin-type field-effect transistor (FinFET) is presented. A new characteristic of the double gate p-type FinFET (p-FinFET) is examined and proven appropriate for sensing voltage variations. On the basis of this characteristic, a novel technique for designing low-power voltage-to-time converters is presented. Then, we develop a digital voltage sensor with a voltage range of 0.7 to 1.1V at a 50-mV resolution. The performance of the proposed sensor is evaluated under a range of voltages and process variations using Simulation Program with Integrated Circuit Emphasis (SPICE) simulations, and the sensor is proven capable of operating under ultra-low power consumption, high linearity, and fairly high-frequency conditions (i.e., 100 MHz).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.685-692
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• 2011

DC/DC switching power converters produce DC output voltages from different DC input sources. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The current mode DC/DC converter is composed of a PWM (pulse width modulation) controller, a MOSFET, and inductor, etc. Pulse width modulation is applied to control and regulate the total output voltage. It is shown that the variation of threshold voltage at MOSFET and the offset voltage increase caused by radiation effects make the PWM pulse unstable. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by simulation program with integrated circuit emphasis (SPICE) and experiments.

• 제어로봇시스템학회논문지
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• 제18권4호
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• pp.371-374
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• 2012

DC/DC switching power converters produce DC output voltages from different stable DC input sources regulated by a bi-polar transistor. The converters can be used in regenerative braking of DC motors to return energy back in the supply, resulting in energy savings for the systems containing frequent stops. The voltage mode DC/DC converter is composed of a PWM (Pulse Width Modulation) controller, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an inductor, and capacitors, etc. PWM is applied to control and regulate the total output voltage. It is shown that the output of DC/DC converter depends on the variation of threshold voltage at MOSFET and the variation of pulse width. In the PWM operation, the missing pulses, the changes in pulse width, and a change in the period of the output waveform are studied by SPICE (Simulation Program with Integrated Circuit Emphasis) and experiments.

• 한국항공우주학회지
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• 제41권1호
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• pp.79-84
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• 2013

DC/DC 컨버터는 임의의 직류전원을 부하가 요구하는 형태의 직류전원으로 변환시키는 효율이 높은 전력변환기이다. DC/DC 컨버터는 PWM-IC(펄스폭 변조 집적회로) 제어기, MOSFET(산화물-반도체 전계 효과 트랜지스터), 인덕터, 콘덴서 등으로 구성되어있다. 코발트 60 ($^{60}Co$) 저준위 감마발생기를 이용한 TID실험에서 방사선의 영향으로 PWM-IC의 전기적 특성중에 문턱전압과 옵셋전압이 증가되고, SEL에 적용된 4종류의 중이온 입자는 PWM-IC의 파형을 불안정하게 만든다. 또한, 입/출력관계의 파형을 SPICE 시뮬레이션 프로그램으로 관찰하였다. PWM-IC의 TID 실험은 30 Krad 까지 수행하였으며, SEL 실험을 제어보드를 구현한 후 LET($MeV/mg/cm^2$)별 cross section($cm^2$)으로 연구하였다.