• 한국통신학회논문지
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• 제25권4B호
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• pp.624-628
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• 2000

본 논문에서는 CDMA 단말기의 전기적 성능에 관한 최소의 요구 사항을 명기한 IS-98B의 항목에서 CDMA 파형의 질(Waveform Quality)을 규정하는 항목인 트래픽로(Traffic Rho)가 최소 성능에 만족하지 않을 경우 CDMA 단말기에 나타나는 현상을 분석하고, CDMA단말기 디자인시 단말기 송신부의 IF(Intermediate Frequency)단에서 TX IF SAW FILTER의 매칭회로를 개선하고 송신단 전원인 3.0V -TX를 발생시키는 LDO(Low Dropout Regulator)의 노이즈 발생을 차단하여 트래픽로 문제 해결방법을 제안한다. 제안 방법을 적용한 후의 파형과 적용전의 파형을 HP8924C 와 HP8595E을 이용하여 비교하여 성능을 개선됨을 보였다.

• Transactions on Electrical and Electronic Materials
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• 제17권3호
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• pp.172-177
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• 2016

Miller feedback compensation is introduced in a low dropout regulator (LDO) in order to obtain a capacitor-free regulator and improve the fast transient response. The conventional LDO has a limited bandwidth because of the large-size output capacitor and parasitic gate capacitance in the power MOSFET. In order to obtain a stable frequency response without the output capacitor, LDO is designed with resistor-capacitor (R-C) compensation and this is achieved with a connection between the gain-stage and the power MOS. An R-C compensator is suggested to provide a pole and zero to improve the stability. The proposed LDO is designed with the 0.35 μm CMOS process. Simulation testing shows that the phase margin in the Bode plot indicates a stable response, which is over 100^o. In the load regulation, the transient time is within 55 μs when the load current changes from 0.1 to 1 mA.

• 한국통신학회논문지
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• 제40권12호
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• pp.2503-2510
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• 2015

본 논문에서는 전력 정보를 측정하기 위한 단상 에너지 측정용 IC의 구현 방법을 제안한다. 제안된 전력 측정용 IC는 2개의 PGA(Programmable Gain Amplifier), 2개의 ${\sum}{\Delta}$ modulator, reference 회로, LDO(Low-dropout) regulator, 온도 센서, 필터부, 계산 엔진, 보정 제어부, 레지스터, 외부 인터페이스로 구성된다. $0.18-{\mu}m$ CMOS 공정으로 제작되었고, 32-pin QFN package로 제작되었다. 구현된 IC는 3.3V 전원을 공급받아 동작하며, 동작 클럭 주파수는 4,096 kHz이고, IC 동작시 소비 전력은 10 mW이다.

• 전기전자학회논문지
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• 제21권2호
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• pp.154-157
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• 2017

본 논문에서는 하나의 입력 전압을 받아 두 개의 출력전압을 가지는 LDO 레귤레이터를 제안한다. 두 개의 출력은 각각의 피드백단을 갖는다. 또한 각각의 피드백 단은 서로 피드백 루프를 공유하며, 서로 피드백 루프를 공유 할 시 서로 미치는 영향을 최소화 하기 위하여 피드백 역할을 하는 PMOS를 추가하여 Load Transient Response를 완화 시켰다. 또한 하나의 바이어스 회로와 하나의 패스 트랜지스터를 사용함으로써 기존 두 개의 출력전압을 얻기 위해 두 개의 LDO 레귤레이터를 사용할 때 대비 면적이 절반으로 줄어들었다.

• Journal of Power Electronics
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• 제15권6호
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• pp.1673-1681
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• 2015

A low dropout (LDO) regulator with a wide-bandwidth is proposed in this paper. The regulator features a Human Body Model (HBM) 8kV-class high robustness ElectroStatic Discharge (ESD) protection circuit, and two error amplifiers (one with low gain and wide bandwidth, and the other with high gain and narrow bandwidth). The dual error amplifiers are located within the feedback loop of the LDO regulator, and they selectively amplify the signal according to its ripples. The proposed LDO regulator is more efficient in its regulation process because of its selective amplification according to frequency and bandwidth. Furthermore, the proposed regulator has the same gain as a conventional LDO at 62 dB with a 130 kHz-wide bandwidth, which is approximately 3.5 times that of a conventional LDO. The proposed device presents a fast response with improved load and line regulation characteristics. In addition, to prevent an increase in the area of the circuit, a body-driven fabrication technique was used for the error amplifier and the pass transistor. The proposed LDO regulator has an input voltage range of 2.5 V to 4.5 V, and it provides a load current of 100 mA in an output voltage range of 1.2 V to 4.1 V. In addition, to prevent damage in the Integrated Circuit (IC) as a result of static electricity, the reliability of IC was improved by embedding a self-produced 8 kV-class (Chip level) ESD protection circuit of a P-substrate-Triggered Silicon Controlled Rectifier (PTSCR) type with high robustness characteristics.

• 한국인터넷방송통신학회논문지
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• 제21권4호
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• pp.123-127
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• 2021

밀리미터파 추적 레이더는 다양한 환경조건에서 운용 가능해야하므로 기존의 추적 레이더에 비해 동등 이상의 연산능력 및 소형화를 요구한다. 본 논문에서는 밀리미터파 추적 레이더에 적용하기 위한 소형 전원공급기 설계 및 구현방안에 대해 기술한다. FPGA/DSP 등 디지털회로의 저전압/고전류 및 전압 정밀도 요구사항 충족을 위해 Point of Load (POL) 컨버터를 적용하였으며, 전력밀도를 향상시키고 시스템 효율을 개선할 수 있다. 부하가 크지 않은 출력전압에는 LDO (Low Dropout) 등을 적용하여 최대 출력 375 W, 출력 전원 8종의 단일 입력-다중 출력 전원공급기를 개발하였다. 최대 부하 조건에서 전압정밀도 <±2 %, 잡음레벨 <50 mVpp 특성을 확인하였다.

• 공학교육연구
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• 제14권3호
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• pp.3-8
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• 2011

Women in the predominantly male-oriented college of engineering which is afflicted by the high dropout rate and the low employment rate of coeds in their majoring fields because of the die-hard male dominant culture. In order to resolve the related problems, P University has been actively engaged in a movement called "Women into Engineering" (WIE) to raise the gender cognitive awareness and to train women engineers for highly qualified work force. As part of the movement, a subject called "Women in Engineering" that focuses on the gender cognitive perspective is effective to reduce the dropout rate and to land a job inside their fields by stimulating their interest in their specialty and masting soft/hard skills. The study was conducted a survey of the coeds who have completed the "Women in Engineering" course to evaluate the degree of satisfaction perceived, and a t-test through comparing the group of the coeds and a group of coeds who have not taken the course. The results showed statistically significant responses indicating that both groups of coeds would like to see WIE offer more basic engineering courses like "Women in Engineering". This may lay the foundation to offer other major engineering courses for juniors and seniors that emphasize the gender cognitive approach.

• 공학교육연구
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• 제17권5호
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• pp.8-12
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• 2014

Women in engineering subject were developed for women included engineering education in Korea. Women in the predominantly male-oriented college of engineering which is afflicted by the high dropout rate and the low employment rate of coeds in their majoring fields because of the die-hard male dominant culture. In order to resolve the related problems, Our University has been actively engaged in a movement called "Women into Engineering" (WIE) to raise the gender cognitive awareness and to train women engineers for highly qualified work force. As part of the movement, a subject called "Women in Engineering" that focuses on the gender cognitive perspective is effective to reduce the dropout rate and to land a job inside their fields by stimulating their interest in their specialty made soft/hard skills. The study was conducted a survey of the coeds who have completed the "Women in Engineering" course to evaluate the degree of satisfaction perceived, and a t-test through comparing the group of the coeds and a group of coeds who have not taken the course. The results showed statistically significant responses indicating that both groups of coeds would like to see WIE offer more basic engineering courses like "Women in Engineering." This may lay the foundation to offer other major engineering courses for juniors and seniors that emphasize the gender cognitive approach.

• 한국산학기술학회논문지
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• 제12권6호
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• pp.2729-2734
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• 2011

본 논문에서는 DC 정합회로를 갖는 능동 Replica LDO 레귤레이터에 대하여 나타내었다. Replica단과 출력단의 DC전압을 정합하기 위하여 DC정합회로를 설계하였다. 능동 Replica LDO 레귤레이터의 PSR특성은 일반적인 레귤레이터 보다 큰 값을 가질 수 있다. 설계된 DC정합회로는 Replica 레귤레이터에서 발생할 수 있는 단점을 줄여준다. 또한 전체회로를 능동회로로 설계함으로써 칩면적을 줄이고 수동저항을 사용할 때 발생하는 열잡음을 제거할 수 있다. 0.35um CMOS 파라미터를 사용하여 HSPICE 시뮬레이션한 결과, DC정합회로를 이용하여 설계된 레귤레이터의 PSR특성은 -28dB@10Hz로써 DC정합회로를 사용하지 않는 일반적인 레귤레이터의 -17dB@10Hz보다 개선될 수 있음을 확인하였다. 레귤레이터의 DC출력 전압은 3V이다.

• Educational Technology International
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• 제17권2호
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• pp.229-251
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• 2016

This study was designed to investigate the relationship between middle school students' smart media competency and online learning outcomes. The context of this study was on online inquiry-based mathematics and science learning environment, and four-hundred and fifty-five (455) 7^th to 9^th grade students in Korea participated in this research. To assess students' smart device competency, Smart Media Literacy Quotient (SMLQ) which consisted of 18 items regarding the operation ability of smart media and its application (14 items) and positive beliefs of smart media (4 items) was administered to each student. The findings of this study first showed that students' smart media literacy varied according to their characteristics such as gender, grade, class (subject), and socio-economic status. Female students' scores were higher in overall smart media literacy operation and learning ability of smart media than male students. 7^th grade middle school students represented lower smart media literacy scores, compared to 8^th and 9^th graders. Also, minority students were significantly lower in smart media literacy, operation and learning ability of smart media, and positive belief of smart media than the non-minority students. Second, overall smart media literacy and operation and learning ability of smart media varied among high, medium, and low score achievers in inquiry tasks. Low scored students in inquiry tasks were significantly lower in overall smart media literacy and operation and learning ability of smart media than medium scored students. Lastly, smart media literacy also varied by students' dropout/completion. Students who dropped out reported significantly lower scores in overall smart media literacy, operation and learning ability of smart media, and positive belief of smart media.