출력전류 제어 기능이 향상된 고휘도 LED 구동 IC 설계

송기남,한석붕,Song, Ki-Nam,Han, Seok-Bung 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.8

In this paper, High brightness LED (light-emitting diodes) driver IC (integrated circuit) using new current sensing circuit is proposed. This LED driver IC can provide a constant current with high current precision over a wide input voltage range. The proposed current-sensing circuit is composed of a cascode current sensor and a current comparator with only one reference voltage. This IC minimizes the voltage stress of the MOSFET (metal oxide semiconductor field effect transistor) from the maximum input voltage and has low power consumption and chip area by using simple-structured comparator and minimum bias current. To confirm the functioning and characteristics of our proposed LED driver IC, we designed a buck converter. The LED current ripple of the designed IC is in ${\pm}5%$ and a tolerance of the average LED current is lower than 2.43%. This shows much improved feature than the previous method. Also, protections for input voltage and operating temperature are designed to improve the reliability of the designed IC. Designed LED driver IC uses 1.0 ${\mu}m$ X-Fab. BiCMOS process parameters and electrical characteristics and functioning are verified by spectre (Cadence) simulation.

공정 및 공급전압 변화에 강인한 하프브리지 구동 IC의 설계

송기남,김형우,김기현,서길수,장경운,한석붕,Song, Ki-Nam,Kim, Hyoung-Woo,Kim, Ki-Hyun,Seo, Kil-Soo,Jang, Kyung-Oun,Han, Seok-Bung 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.10

In this paper, we propose a novel shoot-through protection circuit and pulse generator for half-bridge driver IC. We designed a robust half-bridge driver IC over a variation of processes and power supplies. The proposed circuit is composed a delay circuit using a beta-multiplier reference. The proposed circuit has a lower variation rate of dead time and pulse-width over variation of processes and supply voltages than the conventional circuit. Especially, the proposed circuit has more excellent pulse-width matching of set and reset signals than the conventional circuit. Also, the proposed pulse generator is prevented from fault operations using a logic gate. Dead time and pulse-width of the proposed circuit are typical 250 ns, respectively. The variation ratio is 68%(170 ns) of maximum over variation of processes and supply voltages. The proposed circuit is designed using $1\;{\mu}m$ 650 V BCD (Bipolar, CMOS, DMOS) process parameter, and the simulations are carried out using Spectre simulator of Cadence corporation.

잡음 내성이 향상된 300W 공진형 하프-브리지 컨버터용 고전압 구동 IC 설계

송기남(Ki-Nam Song),박현일(Hyun-Il Park),이용안(Yong-An Lee),김형우(Hyoung-Woo Kim),김기현(Ki-Hyun Kim),서길수(Kil-Soo Seo),한석붕(Seok-Bung Han) 대한전자공학회 2008 電子工學會論文誌-SD (Semiconductor and devices) Vol.45 No.10

본 논문에서는 1.0㎛ BCD 650V 공정을 이용하여 향상된 잡음 내성과 높은 전류 구동 능력을 갖는 고전압 구동 IC를 설계하였다. 설계된 고전압 구동 IC는 500㎑의 고속 동작이 가능하고, 입력 전압의 범위가 최대 650V이다. 설계된 IC에 내장된 상단 레벨 쉬프터는 잡음 보호회로와 슈미트 트리거를 포함하고 있으며 최대 50V/ns의 높은 dv/dt 잡음 내성을 가지고 있다. 또한 설계된 숏-펄스 생성회로가 있는 상단 레벨 쉬프터의 전력 소모는 기존 회로 대비 40% 이상 감소하였다. 이외에도 상ㆍ하단 파워 스위치의 동시 도통을 방지하는 보호회로와 구동부의 전원 전압을 감지하는 UVLO(Under Voltage Lock-Out) 회로를 내장하여 시스템의 안정도를 향상시켰다. 설계된 고전압 구동 IC의 특성 검증에는 Cadence사의 spectre 및 PSpice를 이용하였다. In this paper, we designed the HVIC(High Voltage Gate Driver IC) which has improved noise immunity characteristics and high driving capability. Operating frequency and input voltage range of the designed HVIC is up to 500㎑ and 650V, respectively. Noise protection and schmitt trigger circuit is included in the high-side level shifter of designed IC which has very high dv/dt noise immunity characteristic(up to 50V/ns). And also, power dissipation of high-side level shifter with designed short-pulse generation circuit decreased more that 40% to compare with conventional circuit. In addition, designed HVIC includes protection and UVLO circuit to prevent cross-conduction of power switch and sense power supply voltage of driving section, respectively. Protection and UVLO circuit can improve the stability of the designed HVIC. Spectre and Pspice circuit simulator were used to verify the operating characteristics of the designed HVIC.

잡음 내성이 큰 단일 출력 레벨 쉬프터를 이용한 500 V 하프브리지 컨버터용 구동 IC 설계

박현일,송기남,이용안,김형우,김기현,서길수,한석봉,Park, Hyun-Il,Song, Ki-Nam,Lee, Yong-An,Kim, Hyoung-Woo,Kim, Ki-Hyun,Seo, Kil-Soo,Han, Seok-Bung 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.8

In this paper, we designed driving IC for 500 V resonant half-bridge type power converter, In this single-ended level shifter, chip area and power dissipation was decreased by 50% and 23.5% each compared to the conventional dual-ended level shifter. Also, this newly designed circuit solved the biggest problem of conventional flip-flop type level shifter in which the power MOSFET were turned on simultaneously due to the large dv/dt noise. The proposed high side level shifter included switching noise protection circuit and schmmit trigger to minimize the effect of displacement current flowing through LDMOS of level shifter when power MOSFET is operating. The designing process was proved reasonable by conducting Spectre and PSpice simulation on this circuit using 1${\mu}m$ BCD process parameter.

충격과 마모를 고려한 원자로 핵연료봉 지지격자의 설계

이현아,김종기,송기남,박경진,Lee, Hyun-Ah,Kim, Chong-Ki,Song, Kee-Nam,Park, Gyung-Jin 대한기계학회 2007 大韓機械學會論文集A Vol.31 No.10

The spacer grid set is a component in the nuclear fuel assembly. The set supports the fuel rods safely. Therefore, the spacer grid set should have sufficient strength for the external impact forces such as earthquake. The fretting wear occurs between the spring of the fuel rod and the spacer grid due to flow-induced vibration. Conceptual design of the spacer grid set is performed based on the Independence Axiom of axiomatic design. Two functional requirements are defined for the impact load and the fretting wear, and corresponding design parameters are selected. The overall flow of design is defined according to the application of axiomatic design. Design for the impact load is carried out by using nonlinear dynamic analysis to determine the length of the dimple. Topology optimization is carried out to determine a new configuration of the spring. The fretting wear is reduced by shape optimization using the homology theory. The deformation of a structure is called homologous if a given geometrical relationship holds before, during, and after the deformation. In the design to reduce the fretting wear, the deformed shape of the spring should be the same as that of the fuel rod. This condition is transformed to a function and considered as a constraint in the shape optimization process. The fretting wear is expected to be reduced due to the homology constraint. The objective function is minimizing the maximum stress to allow a slight plastic deformation. Shape optimization results are confirmed through nonlinear static analysis.

대기전력 절감을 위한 원격 전력모니터링 및 제어 기능을 갖는 임베디드 웹서버의 설계

이용안(Yong-An Lee),송기남(Ki-Nam Song),임동민(Dong-Min Lim),한석붕(Seok-Bung Han) 제어로봇시스템학회 2009 제어로봇시스템학회 합동학술대회 논문집 Vol.2009 No.12

최근 에너지 절약에 대한 관심이 높아지면서 대기전력을 줄이기 위한 다양한 기술 개발이 진행되고 있다. 본 논문에서는 이러한 기술 개발의 일환으로 대기전력 절감 기능을 갖는 임베디드 웹서버를 제안한다. 제안한 임베디드 웹서버는 실시간 전력모니터링 기능 및 원격 제어 기능을 제공한다. 또한 대기 전력 자동 차단 알고리즘을 적용하여 가전기기의 대기전력을 자동 차단하는 기능을 갖는다. 제안한 임베디드 웹서버를 적용한 테스트 보드를 구현하고, 실제 가전기기와 연동하여 실시간 테스트 보드를 구현하고, 실제 가전기기와 연동하여 실시간 전력모니터링 및 원격제어 기능과 대기전력 자동 차단 기능을 검증한다. 그리고 대기전력을 측정함으로써 대기전력 절감 효과가 있음을 확인하다.

초고온헬륨루프 STS316 인쇄기판형 열교환기 예비 열해석

김찬수(Chan Soo Kim),송기남(Ki Nam Song),홍성덕(Sung-Deok Hong),김용완(YongWan Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

KAERI is operating a very high temperature Helium Experimental LooP(HELP) to verify the performance of bench-scale key-components for nuclear hydrogen production. A stainlee steel 316 printed circuit heat exchanger was installed in HELP. Its operation condition is high temperature and high pressure condition. Therefore, the thermal-stress analysis is required to assure the high temperature structural integrity. In this study, pre-thermal analysis at the effective heat-transfer region is performed to provide input data for the structural analysis. It was assumed that the conduction in the heat exchanger is negligible and the flow distribution of the channels is uniform. The calculated results show that the uniform flow distribution results in the non-uniform pressured drop distribution. In the future, the computational fluid dynamics analysis will be required at the uniform pressure drop distribution condition. The analytical results will be compared with the experimental results in HELP.

새로운 전류 감지기를 사용한 일반조명용 고휘도 LED 구동 IC 설계

한석붕(Seok Bung Han),송기남(Ki Nam Song),정상배(Sang Bae Jeong) 제어로봇시스템학회 2010 제어로봇시스템학회 합동학술대회 논문집 Vol.2010 No.6

본 논문에서는 일반조명용으로 사용하는 350mA급 고휘도 LED를 구동할 수 있는 LED 구동 IC를 제안한다 설계한 IC는 평균 LED 전류의 정밀도가 우수하고 간단한 구조의 새로운 전류 감지회로를 사용한다. 특히, 감지 전류 비교기는 하나의 기준 전압과 일반 비교기를 이용하여 구조가 간단하고 전력 소모가 적다, 설계한 IC를 사용한 벅 컨버터는 ±5% 의 LED 전류 리플을 가지고, 평균 LED 전류의 오차율이 최대 2.43%로써 우수하다. 그리고 동작의 신뢰성을 높이기 위해 입력 전압 및 동작 온도에 대한 보호회로를 설계한다. 설계한 LED 구동 IC는 BiCMOS 공정 파라미터를 사용하였고, Spectre(Cadence)를 이용한 시뮬레이션을 통해 전기적 특성을 검증하였다.

등가하중을 이용한 원자로 핵연료봉 지지격자 스프링의 비선형 응답 구조 최적설계

김도원(Do-Won Kim),이현아(Hyun-Ah Lee),송기남(Ki-Nam Song),김용일(Yong-Il Kim),박경진(Gyung-Jin Park) 대한기계학회 2007 大韓機械學會論文集A Vol.31 No.12

The spacer grid set is a part of a nuclear fuel assembly. The set has a spring and the spring supports the fuel rods safely. Although material nonlinearity is involved in the deformation of the spring, nonlinearity has not been considered in design of the spring. Recently a nonlinear response structural optimization method has been developed using equivalent loads. It is called nonlinear response optimization equivalent loads (NROEL). In NROEL, the external loads are transformed to the equivalent loads (EL) for linear static analysis and linear response optimization is carried out based on the EL in a cyclic manner until the convergence criteria are satisfied. EL is the load set which generates the same response field of linear analysis as that of nonlinear analysis. Shape optimization of the spring is carried out based on EL. The objective function is defined by minimizing the maximum stress in the spring while mass is limited and the support force of the spring is larger than a certain value. The results are verified by nonlinear response analysis. ABAQUS is used for nonlinear response analysis and GENESIS is employed for linear response optimization.

등가하중을 이용한 원자로 핵연료봉 지지격자 스프링의 비선형 응답 구조 최적설계

김도원(Do-Won Kim),이현아(Hyun Ah Lee),송기남(Ki-Nam Song),김용일(Yong-Il Kim),박경진(Gyung-Jin Park) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

The spacer grid set is a part of a nuclear fuel assembly The set has a spring and the spring supports the fuel rods safely Although material nonlinearity is involved in the deformation of the spring, nonlinearity has not been considered in design of the spring. Recently a nonlinear response structural optimization method has been developed using equivalent loads. It is called nonlinear response optimization equivalent loads (NROEL). In NROEL, the extemalloads are transformed to the equivalent loads (EL) for linear static analysis and linear response optimization is carried out based on the EL in a cyclic manner until the convergence criteria are satisfied. EL is the load set which generates the same response field of linear analysis as that of nonlinear analysis. Shape optimization of the spring is carried out based on EL. The objective function is defined by minimizing the maximum stress in the spring while mass is limited and the support force of the spring is larger than a certain value. The results are verified by nonlinear response analysis. ABAQUS is used for nonlinear response analysis and GENESIS is employed for linear response optimization.