• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.11-12
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• 2005

2 차원 MEDICI 시뮬레이터를 이용하여 CMOS 회로의 전기적 특성을 조사하였다. CMOS 인버터 회로는 LDMOSFET를 이용하였는데, LDMOSFET에서 전류 및 스위칭 특성에 많은 영향을 주는 곳은 채널이라고 생각되는데, 채널에서의 불순물 농도 변화에 의한 CMOS 회로의 voltage transfer특성, low input voltage($V_{IL}$), high input voltage($V_{IH}$)등을 조사하였다. LDMOSFET에서 N 채널의 농도는 $V_{IL}$에, P 채널의 농도는 $V_{IH}$에 많은 영향을 주었다.

• 한국정보통신학회논문지
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• 제18권5호
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• pp.1155-1161
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• 2014

본 논문에서는 DC-DC 부스트 컨버터의 최소 입력전압을 250mV 까지 낮출 수 있도록 하는 저전압 스타트업 전압 발생기를 제안 하였다. 제안된 스타트업 전압 발생기는 250mV의 입력전압을 500mV 이상으로 승압시켜 커패시터에 충전한다. 이후, 커패시터에 저장된 전압으로 부스트 컨버터를 시동시킴으로써, 250mV의 낮은 입력 전압에서도 부스트 컨버터가 동작을 시작할 수 있도록 하였다. 부스트 컨버터가 정상 동작한 후에는, 부스트 컨버터에 의하여 만들어지는 승압된 출력전압을 다시 부스트 컨버터의 전원으로 사용하게 함으로써, 스타트업 동작 후에는 기존 부스트 컨버터와 동일한 높은 전력 변환 효율로 동작 하도록 하였다. 제안된 스타트업 전압 발생기는 낮은 입력전압에서 트랜지스터의 바디전압을 조절하여 트랜지스터의 문턱전압을 낮춤으로써, 입력전압을 승압시키는 딕슨 차지펌프에 높은 클럭 주파수와 큰 전류를 공급하도록 하였다. 제안된 스타트업 전압 발생기는 $0.18{\mu}m$ CMOS 공정으로 제작되었으며, 250mV의 입력전압에서 생성된 클럭 주파수와 출력전압은 각각 34.5kHz와 522mV였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.210-212
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• 2018

A new switching mode has been proposed to obtain high power factor and low THD in single stage AC-DC converter. The conventional voltage mode control in critical conduction mode distorts input current shape with poor THD in flyback topology. Once TRIAC dimmer is connected, visible flicker in the LED lamp is easily detected due to a lack of TRAIC holding current near the input voltage zero cross. The newly proposed method can shape the input current by providing a desired reference voltage so that low THD is obtained by ideal sinusoidal input current in case of no dimmer connection and flat input current performs good TRIAC dimmer compatibility in phase-cut dimming condition. To confirm the validity of the proposed method, theoretical analysis and experimental result from 8W dimmable LED lighting system are presented.

• 전기학회논문지
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• 제66권12호
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• pp.1721-1724
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• 2017

This paper presents a numerical optimization technique to reduce input current and torque ripple of the low voltage BLDC motor using core, coil and switching angle optimization. The optimization technique is employed using the generalized response surface method(RSM) and sampling minimization technique with FEM. A 50W 24V BLDC motor is used to verify the proposed algorithm. As optimizing results, the input current is reduced from 2.46 to 2.11[A], and the input power is reduced from 59 [W] to 51 [W] at the speed of 1000 [rpm]. Also, applied the same optimization algorithm, the torque ripple is reduced about 7.4 %. It is confirmed that the proposed technique is a reasonably useful tool to reduce the consuming current and torque ripple of the low voltage BLDC motor for a compact and efficient design.

• 전력전자학회논문지
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• 제25권3호
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• pp.157-161
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• 2020

High voltage gain converters are essential for distributed power generation systems with renewable energy sources, such as fuel cells and solar cells, because of their low voltage characteristics. This paper introduces a novel nonisolated DC-DC converter topology developed by combining an inverting buck-boost converter and voltage multipliers. In the proposed converter, the input voltage is connected in series with the output, and the majority of the input power is directly delivered to the load. The voltage multipliers are stacked in series to achieve high step-up voltage gain. The voltage stress across all of the switches and capacitors can be significantly reduced. As a result, the switches with low voltage ratings can be used to achieve high efficiency and low cost. To verify the validity of the proposed topology, a 360-W prototype converter is built to obtain the experimental results.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.85-90
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• 2012

This paper presents a topology structure and control method for an input-parallel-output-series(IPOS) inverter system which is suitable for high input current, high output voltage, and high power applications. In order to ensure the normal operation of the IPOS inverter system, the control method should achieve input current sharing(ICS) and output voltage sharing(OVS) among constituent modules. Through the analysis in this paper, ICS is automatically achieved as long as OVS is controlled. The IPOS inverter system is controlled by a three-loop control system which is composed of an outer common-output voltage loop, inner current loops and voltage sharing loops. Simulation results show that this control strategy can achieve low total harmonic distortion(THD) in the system output voltage, fast dynamic response, and good output voltage sharing performance.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.706-711
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• 2014

A low power 6-bit flash ADC that uses an input voltage range detection algorithm is described. An input voltage level detector circuit has been designed to overcome the disadvantages of the flash ADC which consume most of the dynamic power dissipation due to comparators array. In this work, four digital input voltage range detectors are employed and each input voltage range detector generates the specific clock signal only if the input voltage falls between two adjacent reference voltages applied to the detector. The specific clock signal generated by the detector is applied to turn the corresponding latched comparators on and the rest of the comparators off. This ADC consumes 68.82 mW with a single power supply of 1.2V and achieves 4.3 effective number of bits for input frequency up to 1 MHz at 500 MS/s. Therefore it results in 4.6 pJ/step of Figure of Merit (FoM). The chip is fabricated in 0.13-um CMOS process.

• E2M - 전기 전자와 첨단 소재
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• 제9권2호
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• pp.138-145
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• 1996

A multilayer piezoelectric transformer (MPT) which generates a high voltage dc power with low driving voltage and high voltage setup ratio was made by the tape casting method. The measured electrical characteristics of the MPT agreed with the results simulated from the equivalent circuit of the MPT. With increasing the number of layer in the MPT, the resonance curve of the input cur-rent revealed an asymmetry due to the increasing input capacitance, while that of output dc voltages revealed symmetry. The MPT which has very thin layer was excellently characterized as low driving voltage and high voltage setup ratio. The output dc voltage is nonlinearly influenced by the number of layer in the MPT.

• Journal of Power Electronics
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• 제10권1호
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• pp.9-13
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• 2010

This paper proposes an input-series-output-parallel connected ZVS full bridge converter with interleaved control for photovoltaic power conditioning systems (PV PCS). The input-series connection enables a fully modular power-system architecture, where low voltage and standard power modules can be connected in any combination at the input and/or at the output, to realize any given specifications. Further, the input-series connection enables the use of low-voltage MOSFETs that are optimized for a very low RDSON, thus, resulting in lower conduction losses. The system costs decrease due to the reduced current, and the volumes of the output filters due to the interleaving technique. A topology for a photovoltaic (PV) dc/dc converter that can dramatically reduce the power rating and increase the efficiency of a PV system by analyzing the PV module characteristics is proposed. The control scheme, consisting of an output voltage loop, a current loop and input voltage balancing loops, is proposed to achieve input voltage sharing and output current sharing. The total PV system is implemented for a 10-kW PV power conditioning system (PCS). This system has a dc/dc converter with a 3.6-kW power rating. It is only one-third of the total PV PCS power. A 3.6-kW prototype PV dc/dc converter is introduced to experimentally verify the proposed topology. In addition, experimental results show that the proposed topology exhibits good performance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.646-649
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• 1999

A new isolated boost dc to dc convertor suitable for a low input voltage application is proposed. The proposed convertor features the low switch current stresses, the wide input voltage range operation, and the inherent inrush current protection characteristics, essential to design a low to high voltage conversion circuit. A comparative analysis and experimental results are presented to show the validity of the proposed convertor.