UHF RFID 태그 칩용 저전력, 저면적 비동기식 EEPROM 설계

백승면,이재형,송성영,김종희,박문훈,하판봉,김영희,Baek, Seung-Myun,Lee, Jae-Hyung,Song, Sung-Young,Kim, Jong-Hee,Park, Mu-Hun,Ha, Pan-Bong,Kim, Young-Hee 한국정보통신학회 2007 한국정보통신학회논문지 Vol.11 No.12

본 논문에서는 $0.18{\mu}m$의 EEPROM cell을 사용하여 수동형 UHF RFID 태그 칩에 사용되는 저전력, 저면적의 1Kbits 비동기식 EEPROM IP를 설계하였다. 저면적 회로 설계 기술로는 $0.18{\mu}m$ EEPROM 공정을 이용하여 비동기식 EEPROM IP를 설계하므로 command buffer와 address buffer를 제거하였고 separate I/O 방식을 사용하므로 tri-state 데이터 출력 버퍼(data output buffer)를 제거하였다. 그리고 저전압(low voltage)의 VDD에서 EEPROM cell이 필요로 하는 고전압(high voltage)인 VPP와 VPPL 전압을 안정적으로 공급하기 위해 기존의 PN 접합 다이오드 대신 Schottky 다이오드를 사용한 Dickson 전하펌프를 설계하므로 전하펌프의 펌핑단(pumping stage)의 수를 줄여 전하펌프가 차지하는 면적을 줄였다. 저전력 회로 설계 기술로 Dickson 전하 펌프(charge pump)를 이용하여 VPP generator를 만들고 Dickson 전하펌프의 임의의 노드 전압을 이용하여 프로그램과 지우기 모드에서 각각 필요로 하는 VPPL 전압을 선택하도록 하게 해주는 VPPL 전원 스위칭 회로를 제안하여 쓰기전류(write current)를 줄이므로 저전력 EEPROM IP를 구현하였다. $0.18{\mu}m$ 공정을 이용하여 설계된 비동기식 EEPROM용 테스트 칩은 제작 중에 있으며, 비동기식 1Kbits EEPROM의 레이아웃 면적은 $554.8{\times}306.9{\mu}m2$로 동기식 1Kbits EEPROM에 비해 레이아웃면적을 11% 정도 줄였다. In this paper, a low-power and small-area asynchronous 1 kilobit EEPROM for passive UHF RFID tag chips is designed with $0.18{\mu}m$ EEPROM cells. As small area solutions, command and address buffers are removed since we design asynchronous I/O interface and data output buffer is also removed by using separate I/O. To supply stably high voltages VPP and VPPL used in the cell array from low voltage VDD, Dickson charge pump is designed with schottky diodes instead of a PN junction diodes. On that account, we can decrease the number of stages of the charge pump, which can decrease layout area of charge pump. As a low-power solution, we can reduce write current by using the proposed VPPL power switching circuit which selects each needed voltage at either program or write mode. A test chip of asynchronous 1 kilobit EEPROM is fabricated, and its layout area is $554.8{\times}306.9{\mu}m2$., 11% smaller than its synchronous counterpart.

UHF RFID 태그 칩용 저전력 EEPROM설계

이원재,이재형,박경환,이정환,임규호,강형근,고봉진,박무훈,하판봉,김영희,Yi, Won-Jae,Lee, Jae-Hyung,Park, Kyung-Hwan,Lee, Jung-Hwan,Lim, Gyu-Ho,Kang, Hyung-Geun,Ko, Bong-Jin,Park, Mu-Hun,Ha, Pan-Bong,Kim, Young-Hee 한국정보통신학회 2006 한국정보통신학회논문지 Vol.10 No.3

본 논문에서 는 플래쉬 셀을 사용하여 수동형 UHF RFID 태그 칩에 사용되는 저전력 1Kb 동기식 EEPROM을 설계하였다. 저전력 EEPROM을 구현하기 위한 방법으로 다음과 같은 4가지 방법을 제안하였다. 첫째, VDD(=1.5V)와 VDDP(=2.5V)의 이중 전원 공급전압 방식을 사용하였고, 둘째, 동기식 회로 설계에서 클럭(clock) 신호가 계속 클럭킹(clocking)으로 인한 스위칭 전류(switching current)가 흐르는 것을 막기 위해 CKE(Clock Enable) 신호를 사용하였다. 셋째, 읽기 사이클에서 전류 센싱(current sensing) 방식 대신 저전력 소모를 갖는 clocked inverter를 사용한 센싱 방식을 사용하였으며, 넷째, 쓰기 모드시 Voltage-up 변환기(converter) 회로를 사용하여 기준전압 발생기(Reference Voltage Generator)에는 저전압인 VDD를 사용할 수 있도록 하여 전력 소모를 줄일 수가 있었다. $0.25{\mu}m$ EEPROM 공정을 이용하여 칩을 제작하였으며, 1Kb EEPROM을 설계한 결과 읽기 모드와 쓰기 모드 시에 소모되는 전력은 각각 $4.25{\mu}W$와 $25{\mu}W$이고, 레이아웃 면적(layout area)은 $646.3\times657.68{\mu}m^2$이다. In this paper, a low-power 1Kb synchronous EEPROM is designed with flash cells for passive UHF RFID tag chips. To make a low-power EEPROM, four techniques are newly proposed. Firstly, dual power supply voltages VDD(1.5V) and VDDP(2.5V), are used. Secondly, CKE signal is used to remove switching current due to clocking of synchronous circuits. Thirdly, a low-speed but low-power sensing scheme using clocked inverters is used instead of the conventional current sensing method. Lastly, the low-voltage, VDD for the reference voltage generator is supplied by using the Voltage-up converter in write cycle. An EEPROM is fabricated with the $0.25{\mu}m$ EEPROM process. Simulation results show that power dissipations are $4.25{\mu}W$ in the read cycle and $25{\mu}W$ in the write cycle, respectively. The layout area is $646.3\times657.68{\mu}m^2$.

저전압 SoC용 밴드갭 기준 전압 발생기 회로 설계

이태영,이재형,김종희,심외용,김태훈,박무훈,하판봉,김영희,Lee, Tae-Young,Lee, Jae-Hyung,Kim, Jong-Hee,Shim, Oe-Yong,Kim, Tae-Hoon,Park, Mu-Hun,Ha, Pan-Bong,Kim, Young-Hee 한국정보통신학회 2008 한국정보통신학회논문지 Vol.12 No.1

The band-gap reference voltage generator which can be operated by low voltage is proposed in this paper. The proposed BGR circuit can be realized in logic process by using parasitic NPN BJTs because a $Low-V_T$ transistors are not necessary. The proposed BGR circuit is designed and fabricated using $0.18{\mu}m$ triple-well process. The mean voltage of measured VREF is 0.72V and the three sigma$(3{\sigma})$ is 45.69mv. 본 논문에서는 $Low-V_T$ 트랜지스터가 필요 없는 로직공정으로 Parasitic NPN BJT를 이용하여 저 전압에서 동작 가능한 밴드갭 기준전압 발생기 회로를 제안하였다. $0.18{\mu}m$ triple-well 공정을 사용한 BGR회로를 측정 한 결과 VREF의 평균전압은 0.72V $3{\sigma}$는 45.69mV로 양호하게 측정되었다.

TFT -LCD 구동 IC용 커패시터 내장형 DC-DC 변환기 설계

임규호,강형근,이재형,손기성,조기석,백승면,성관영,이용진,박무훈,하판봉,김영희,Lim Gyu-Ho,Kang Hyung-Geun,Lee Jae-Hyung,Sohn Ki-Sung,Cho Ki-Seok,Baek Seung-Myun,Sung Kwan-Young,Li Long-Zhen,Park Mu-Hun,Ha Pan-Bong,Kim Young-Hee 한국정보통신학회 2006 한국정보통신학회논문지 Vol.10 No.7

A non-overlap boosted-clock charge pump(NBCCP) with internal pumping capacitor, an advantageous circuit from a minimizing point of TFT-LCD driver IC module, is proposed in this paper. By using the non-overlap boosted-clock swinging in 2VDC voltage, the number of pumping stages is reduced to half and a back current of pumping charge from charge pumping node to input stage is also prevented compared with conventional cross-coupled charge pump with internal pumping capacitor. As a result, pumping current of the proposed NBCCP circuit is increased more than conventional cross-coupled charge pump, and a layout area is decreased. A proposed DC-DC converter for TFT-LCD driver IC is designed with $0.18{\mu}m$ triple-well CMOS process and a test chip is in the marking. 본 논문에서는 TFT-LCD 구동 IC 모듈의 소형화측면에서 유리한 DC-DC 변환기 회로인 펌핑 커패시터 내장형 비중첩 부스트-클락 전하펌프 (Non-overlap Boosted-Clock Charge Pump: NBCCP) 회로가 제안되었다 .2VDC 전압으로 스윙하는 비중첩 부스트-클럭의 사용으로 기존의 펌핑 커패시터 내장형 크로스-커플드 전하펌프에 비해 펌핑 단의 수를 반으로 줄일 수 있었고, 전하 펌핑 노드의 펌핑된 전하가 입력 단으로 역류되는 현상을 방지하였다 . 그 결과 제안된 펌핑 커패시터 내장형 비중첩 부스트-클럭 전하펌프 회로는 기존의 펌핑 커패시터 내장형 크로스-커플드 전하펌프에 비해 펌핑 전류가 증가하였고, 레이아웃 면적은 감소되었다. 제안된 TFT-LCD 구동 IC용 DC-DC 변환기 회로를 $0.18{\mu}m$ Triple-Well CMOS 공정을 사용하여 설계하고, 테스트 칩을 제작 중에 있다.

넓은 전압 범위와 개선된 파워-업 특성을 가지는 밴드갭 기준전압 발생기의 스타트-업 회로

성관영,김종희,김태호,카오투안부,이재형,임규호,박무훈,하판봉,김영희,Sung, Kwang-Young,Kim, Jong-Hee,Kim, Tae-Ho,Vu, Cao Tuan,Lee, Jae-Hyung,Lim, Gyu-Ho,Park, Mu-Hum,Ha, Pan-Bong,Kim, Young-Hee 한국정보통신학회 2007 한국정보통신학회논문지 Vol.11 No.8

본 논문에서는 넓은 동작전압 범위와 저소비 전력 그리고 개선된 파워-업 특성을 가지는 캐스코드 전류 거울형 CMOS 밴드갭 기준전압 발생기의 스타트-업 회로를 제안하였다. 새롭게 제안된 스타트-업 회로는 기존의 스타트-업 회로에 비해 안정적인 파워-업 특성을 가지며 공급전압(VDDA)이 높아지더라도 밴드갭 기준전압 발생기 회로의 동작에 영향을 미치지 않는 것을 모의실험을 통하여 확인하였고 $0.18{\mu}m$ tripple-well CMOS 공정을 이용하여 테스트 칩을 제작하고 측정하였다. 측정 된 기준전압 Vref는 평균값이 738mV이고 $3{\sigma}$는 29.88mV이다. A start-up circuit of the bandgap reference voltage generator of cascode current mirror type with wide operating voltage range and enhanced power-up characteristics is proposed in the paper. It is confirmed by simulation that the newly proposed start-up circuit does not affect the operation of the bandgap reference voltage generatory even though the supply voltage(VDDA) is higher and has more stable power-up characteristic than the conventional start-up circuit. Test chips are designed and fabricated with $0.18{\mu}m$ tripple well CMOS process and their test has been completed. The mean value of measured the reference voltage(Vref) is 738mV and The three sigma value($3{\sigma}$) is 29.88mV.

정상 인체 멜라닌세포 및 B-16 흑색종 세포주에서 상지(桑枝) 추출물의 티로시나제 활성 억제 효과에 관한 연구

송무현,황재영,박영립,황규왕 순천향의학연구소 2000 Journal of Soonchunhyang Medical Science Vol.6 No.2

Background : Recently, the undesirable effects of UV exposure have been increasing because of destruction of ozone layer and excessive solar exposure in enjoying leisure. Therefore, the chance to have uneven skin pigmentations has been increasing. To keep away from the unwanted skin pigmentation, melanogenesis inhibitors have been developed for use in cosmetic preparations for the purpose of skin whitening. Plant extracts having an inhibitory effect in melanin synthesis may be a good choice as a cosmetic ingredient because they have relatively fewer side effects. Objective : In this study, the inhibitory effects of ramulus mori (young twigs of Morus alba L) on tyrosinase activity were investigated cultured normal human melanocytes and B-16 melanoma cells by using enzyme assay and RT-PCR. Methods : Tyrosinase activity was determined by spectrophotometry. The effects of whitening agents (kojic acid, arbutin, licorice extracts and ramulus mori extracts) on mushroom tyrosinase was compared by measuring the IC_(50), the concentration of the compound at which half of the original tyrosinase activity is inhibited. Normal human melanocytes taken from neonatal foreskin and B-16 melanoma cells, tyrosinase activity inhibition was measured by spectrophotometry. We observed tyrosinase volume in B-16 melanoma cells by using PT-PCR. Results : Ramulus mori extracts showed strong inhibitory effect on tyrosinase activity in both normal human melanocytes and B-16 melanoma cells. We also confirm that they have a inhibitory effect on tyrosinase expression in the RT-PCR. Conclusion : This study showed that ramulus mori extracts had strong inhibitory effect against tyrosinase activity. The results suggests that ramulus mori extracts can be used as a new whitening agent.

數學科 問題解決 學習의 指導에 關한 硏究

林在圭,金俊茂,金昭延,李海榮 경북대학교 과학교육연구소 1989 科學敎育硏究誌 Vol.13 No.-

The purpose of this article is to establish some principles in helping students study in order to enhance the ability of solving problems reasonably by using fundamental mathematical skills, and to bring forth the improvement of mathematics education by using the above mentioned principles. In this work we investigate the following subjects ; (1) Fundamental concepts and strategies of teaching students for mathematics problem solving achieved in nineteen eighties in and out of Korea. (2) Current status of problem solving ability of middle and highschool students and teachers. (3) We first made 「motivation-advice cards」 about the problem solving strategy according to the classification of problem solving thought format, and then we used them in highschool classes. We test the result. We obtained the following conclusions ; (1) The style of test problems has to be changed from multiple choice form which is widely used in various evaluation examinations to writing style. (2) Studies of teaching method to help students extend their creativity, and making good problems and invention of instructive devices are required. (3) After making the students aware of the importance of problem solving strategy and of the way how to use it, we have to lead the students to acquire the habit of using them.

USLE 계열모형의 매개변수 산정에 관한 연구

임재영,서규우,송일준,송무효 동의대학교 산업기술개발연구소 2000 産業技術硏究誌 Vol.14 No.-

In this study, USLE series parameter's characters are assessed each parameter. Main topic is propose for Assesment method. In case of Soil erosion energy factor for single storm, return period is commended 5 year. In case of Soil Erodibility factor, Percentage of Clay is increase then K value is decrease. In case of Slope Steepness-length factor, If the homogeneous slope length divide into short length, Sediment yield become exaggerated estimation. In condition of low steepness Slope basin, As the sensibility of Slope gradient, estimation of slope gradient must to be exceedingly careful. Also, the average slope where is low slope gradient basin is to be prudent. In spite of the same site, design engineer understood that site is convex configuration, soil erosion is estimated very much. In this study proposed cover factor estimation process. In case of soil conservation practice factor, I proposed that P factor substituted for delivery ratio, developed by US Forest Service.

KISTI-ACOMS를 기반으로 한 대한치과보존학회 온라인논문투고관리시스템 개발

박재원,강무영 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.6

Societies are important sources of new information for users. However. most of these societies still rely on traditional. or rather ancient methods for gathering and servicing the information. Furthermore. most of the societies are trying to electrify processes such as managing members and paper submission as well as the process managing the information for service but are limited due to financial and technical reasons. Therefore. KISTI(Korea Institute of Science and Technology Information) has developed the 『KISTI ACOMS(KISTI Article COntribution Management System)』 as part of the national project for automating the process of processing academic information by societies. in order to convert journals published by academic societies in Korea into an electronic form and make them accessible on the Internet. This system has been developed in the year 2001 and has since been distributed to societies free of charge. The number of societies requesting the service has risen recently. which prompted us to take more recommendations of the societies that adopt this system into account in expanding and standardizing the area of service being provided by the system.

관계 데이타베이스에서의 불확정 정보에 대한 질의어 최적화에 관한 연구

李在舞,吳廉德 釜山敎育大學 1988 부산교육대학 논문집 Vol.24 No.1

There are many types of information occurred in real-world which are required not only definite information but also indefinite information. We define tables to represent various kinds of indefinite information which are applicable to any relational operators and show that this tables are well-defined. Also, we define relational algebraic operations or indefinite infromation under these tables and consider query optimization algorithm and propose various types of answers for a query under the defined IIRS(Indefinite Information Representation System). Consequently, we show that if any query is transformed into reltional algebraic expression and is applied to these table, many kinds of answer types which include definite type, indefinite type, and indefinite type condition, can be given to the users.