Design and Optimization of Power-Gated Circuits With Autonomous Data Retention

Jun Seomun,Youngsoo Shin IEEE 2011 IEEE transactions on very large scale integration Vol.19 No.2

<P>Power gating has been widely employed to reduce subthreshold leakage. Data retention elements (flip-flops and isolation circuits) are used to preserve circuit states during standby mode, if the states are needed again after wake-up. These elements must be controlled by an external power management unit, causing a network of control signals implemented with extra wires and buffers. A power-gated circuit with autonomous data retention (APG) is proposed to remove the overhead involved in control signals. Retention elements in APG derive their control by detecting rising potential of virtual ground rails when power gating starts, i.e., they control themselves without explicit control signals. Design of retention elements for APG is addressed to facilitate safe capturing of circuit states. Experiments with 65-nm technology demonstrate that, compared to standard power gating, total wirelength, and average wiring congestion are reduced by 8.6% and 4.1% on average, respectively, at a cost of 6.8% area increase. In order to fast charge virtual ground rails, a pMOS switch driven by a short pulse is employed to directly provide charges to virtual ground. This helps retention elements avoid short-circuit current while making transition to standby mode. The optimization procedure for sizing pMOS switch and deciding pulse width is addressed, and assessed with 65-nm technology. Experiments show that, compared to standard power gating, APG reduces the delay to enter and exit the standby mode by 65.6% and 28.9%, respectively, with corresponding energy dissipation during the period cut by 46.1% and 36.5%. Standby mode leakage power consumption is also reduced by 15.8% on average.</P>

Synthesis of Active-Mode Power-Gating Circuits

Jun Seomun,Shin, Insup,Youngsoo Shin IEEE 2012 IEEE transactions on computer-aided design of inte Vol.31 No.3

<P>Active leakage is transient, which can be suppressed by design techniques such as dual-<I>Vt</I>. Active-mode power-gating (AMPG) can further reduce active leakage by power-gating groups of gates that perform computations with results that are not loaded due to clock-gating. AMPG involves several challenges; the grouping of gates must take circuit timing into account, and current switches need to be sized to preserve power network integrity as well as circuit timing. We propose solutions to these problems in the content of the entire process of synthesizing AMPG circuits. The physical design of AMPG circuits is also difficult due to the large number of virtual ground rails that must be mutually isolated. We address these issues by integrating placement with power network synthesis. Experiments on several test circuits implemented in 45-nm technology demonstrate the effectiveness of AMPG in the circuits that we synthesized, in terms of power consumption, area, wirelength, and timing.</P>

인버터 TIG 용접기의 펄스전류 제어에 관한 연구

서문준(Jun Seomun),김규식(Gyu-Sik Kim),원충연(Chung-Yuen Won),민명식(Myung-Sik Min),최규하(Gyu-Ha Choi),목형수(Hyung-Su Mok) 전력전자학회 1998 전력전자학술대회 논문집 Vol.- No.-

In this paper, the inverter TIG (Tungsten Inert Gas) welding system with high power efficiency by means of pulse current control of welding process is presented In TIG welding, pulse current control is utilized in order to attain less spatter and high welding performance. The four factors which determine the welding performance of the pulse current are frequency, base current, peak current, and peak current duty ratio, The input power depends on base current, peak current, and peak current duty ratio, In this paper, we analyze these three factors should be controlled to achieve minimum power input. To demonstrate the practical significance of our results, we present some experimental results as well as simulation results.<br/> <br/>

반응부의 유동해석을 통한 열플라즈마 가스처리기의 효율 개선

서문준(Jun SeoMun),정진도(Jin-Do Chung),구경완(Kyung-Wan Koo) 대한전기학회 2011 전기학회논문지 Vol.60 No.3

This study explores the numerical analysis method of fluid dynamics in the reaction section to improve the gas processing efficiency in the hazardous gas removal by atmospheric thermal plasma. This study also intends to contribute in technology advance to improve the processing efficiency and make the process more stable. Numerical analysis of temperature distribution in the reaction section dependent on the change in flow velocity of Ar and plasma temperature change, which are major control variables in the cracking process of HFC-23 using arc plasma, was done. The characteristic of incoming oxygen by temperature suggested that when temperature increased to 1600K, 1700K, 1800K respectively, the range of cracking temperature 1500K increased to 75.0%, 83.3%, 90.2% respectively. The temperature change of Ar by velocity change was widest in the area higher than 1500K when the velocity was 2.5m/s; however, since there was no big difference when the velocity was 2m/s, it is believed that 2 m/s would be most proper.

저항 스폿 용접 시스템의 고성능 전력 제어

서문준(Jun Seomun),김규식(Gyu-Sik Kim),원충연(Chung-Yuen Won),최규하(Gyu-Ha Choe),목형수(Hyung Soo Mok) 제어로봇시스템학회 1998 제어로봇시스템학회 합동학술대회 논문집 Vol.1998 No.3

노인장기요양보험 재가서비스의 문제점과 개선방안

이준우(Lee, Jun Woo),서문진희(Jin Hee Seomun) 한국노년학회 2009 한국노년학 Vol.29 No.1

본 연구는 제도 시행 초기인 2008년 10월 현재 여러 부분에서 동시다발적으로 발생하는 노인장기요양보험 재가서비스의 다양한 문제점과 원인을 파악하여 분석한 후, 그에 대한 개선방안을 마련하는 데 목적이 있다. 연구방법은 크게 선행 연구된 2차 자료를 분석하는 문헌조사와 관련 전문가를 대상으로 하는 서베이 조사방식을 통해 진행되었다. 자료의 분석은 길버트와 스펙트의 정책분석틀에 근거하여 대상자체계, 급여(서비스)체계, 재정체계, 전달체계의 영역으로 구분하여 분석하였다. 본 연구를 통해 도출된 노인장기요양보험 재가서비스의 문제점은 첫째, 대상자체계에서는 가입대상자와 서비스 대상자의 불일치, 수요자 추계의 문제점 및 등급판정 관련 문제 등이 있으며, 둘째, 서비스 체계에서는 서비스 인력의 전문성 결여, 방문요양기관 인력기준 완화로 인한 서비스 질 저하, 서비스 이용시간 제한의 불합리성 및 방문요양 수가의 등급별 균등지급의 문제가 있는 것으로 나타났다. 셋째, 재정체계에서는 본인부담금과 비급여항목으로 인한 이용자 부담과중, 기존운영비 지원기관에 대한 지원중단으로 인한 서비스의 사각지대 발생 및 구조조정 및 파트타임 증가로 서비스 질 저하 문제가 나타났으며, 마지막으로 전달체계에서는 서비스의 질 관리체계 미비, 재가장기요양기관 남설로 인한 과다 경쟁, 영리적 운영으로 인한 서비스 공공성과 질저하, 대상자 모집의 어려움으로 인한 운영난 및 요양보호사 교육기관 난립으로 인한 과다배출과 부실교육 등의 문제가 있는 것으로 조사되었다. 이상의 결과에 근거하여 다음과 같이 제언하였다. 첫째, 장기적으로 가입자와 서비스 대상자를 일치시킬 필요가 있다. 둘째, 공단직원의 전문성 향상 및 인력충원이 필요하며, 셋째, 등급외자에 대한 효율적 서비스 연계, 넷째, 체계적인 요양보호사 관리시스템 구축 및 서비스 표준지침서 개발, 다섯째, 서비스 내용과 절차에 관한 일부 법규의 수정이 필요하며, 여섯째, 본인부담금의 일부 조정도 필요하다. 일곱째, 노인복지법에 의한 재가시설에 운영비를 지원해야 하며, 여덟째, 관리감독 기관의 모니터링 시스템 강화 및 서비스 제공 기관과 서비스 인력에 대한 평가 체계마련, 그리고 마지막으로 기관설치 기준의 강화가 필요하다. The purpose of this research is to analyze the overall problems at the moment of October 2008, and then to find the improvements of home-help services of the Long-Term Care Insurance(LTCI), which has been revealed many problems since it was released in July 2008. The research uses the literature survey which analyzes 2nd-hand materials studied by other people already, and survey research was executed from active social workers in the area of LTCI. Based on the policy analysis framework of Gilbert and Specht, all the data are analyzed in the scopes of clientㆍbenefit(service)ㆍfinanceㆍtransferring system. This research has found the problems in each scope of home-help services of the LTCI. Firstly, the client system has some problems in mismatching between registered and service clients, estimating client number, and judging service levels. Secondly, the service system reveals deficiency in professionality of social workers, service quality lowering by loose qualification criteria on workers, non-reasonable limitation of service time available, and the same fare system applied to visiting-help service in spite of different levels. Thirdly, in financing system, clients need to pay additional money to get extra services such as meal, hair cutting, bathing etc., due to government financial support stopped, some organizations have to reduce services and replace full-time workers to part-time ones, which makes the service quality worse. Lastly, in the transferring system, the management system for service quality is not well prepared. There are too much competion because of allowing too many home-help service organizations and care worker academies. The suggestions that this research has found to improve the policy are as follows. ① It is desirable to make the registered clients the service ones as many as possible in the long term perspective. ② The LTCI organization requires more workers and higher professionality. ③ Many elderly people who are not eligible now require connection system to be more served. ④ Management system and service manual for care worker are to be developed. ⑤ Laws related to the service contents and process should be modified, the proportion of client charge needs to adjust. ⑥ Home-help service organization licensed by the LTCI needs to be financially supported publicly. ⑦ Monitoring system to home-help service organization needs to be strengthened. ⑧ Evaluation tools to home-help service organization and workers is required. ⑨ Specification to open the home-help service organization needs to be more strict.

Maximizing Frequency and Yield of Power-Constrained Designs Using Programmable Power-Gating

Nam Sung Kim,Sinkar, A.,Jun Seomun,Youngsoo Shin IEEE 2012 IEEE transactions on very large scale integration Vol.20 No.10

<P>A large spread of leakage power due to process variations impacts the total power consumption of integrated circuits (ICs) substantially. This in turn may reduce frequency and/or yield of power-constrained designs. Facing such challenges, we propose two methods using power-gating (PG) devices whose effective width can be adjusted during a post-silicon tuning process. In the first method, we consider processors exhibiting substantial core-to-core frequency and leakage power variations while only a global voltage/frequency domain is supported. Since each core in a processor often has its own PG device, the total width each PG device and the global voltage are tuned jointly to maximize the global frequency for a given power constraint. Our experiment demonstrates that the maximum frequency of 2-, 4-, 8-, and 16-core processors is improved by 5%-21%. In the second method, we take rejected dies due to excessive leakage power. We adjust the width of PG devices such that the dies satisfy their given power constraint. Our experiment shows that 88%-98% of discarded dies violating their power constraint are recovered.</P>

열플라즈마 반응부의 유동해석에 관한 연구

구경완(Kyung-wan Koo),정진도(Jin-do Chung),서문준(Jun SeoMun) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.11