• Title/Summary/Keyword: current sink

Search Result 134, Processing Time 0.029 seconds

The Analysis of Electrical Conduction and Corrosion Phenomena in HVDC Cooling System and the Optimized Design of the Heat Sink of the Semiconductor Devices (HVDC 냉각시스템의 전기전도현상 및 부식현상 기술 분석과 스위칭 소자의 방열판 최적 설계 검토)

  • Kim, Chan-Ki;Park, Chang-Hwan;Kim, Jang-Mok
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.22 no.6
    • /
    • pp.484-495
    • /
    • 2017
  • In HVDC thyristor valves, more than 95% of heat loss occurs in snubber resistors and valve reactors. In order to dissipate the heat from the valves and to suppress the electrolytic current, water with a high heat capacity and a low conductivity of less than 0.2 uS/cm must be used as a refrigerant of the heat sink. The cooling parts must also be arranged to reduce the electrolytic current, whereas the pipe that supplies water to the thyristor heat sink must have the same electric potential as the valve. Corrosion is mainly caused by electrochemical reactions and the influence of water quality and leakage current. This paper identifies the refrigerants involved in the ionization, electrical conductivity, and corrosion in HVDC thyristor valves. A method for preventing corrosion is then introduced. The design of the heat sink with an excellent heat radiation is also analyzed in detail.

Fabrication of GaAs Gunn Diodes With A Double Heat Sink (이중 방열 구조를 갖는 GaAs 건 다이오드 제작)

  • Kim, Mi-Ra;Rhee, Jin-Koo;Chae, Yeon-Sik;Lim, Hyun-Jun;Choi, Jae-Hyun;Kim, Wan-Joo
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.46 no.9
    • /
    • pp.1-6
    • /
    • 2009
  • We fabricated Gunn diodes with a double heat sink which has anode heat sink as well as cathode heat sink for efficient heat dissipation. We compared the DC characteristics of a double heat sink diode with a conventional cathode heat sink Gunn diode. It was shown that the Gunn diode with a single heat sink has the threshold voltage of 3 V, the peak current of 744 mA and the breakdown voltage of 4.8 V. Also, the Gunn diode with a double heat sink showed the threshold voltage of 2.5 V, the peak current of 778 mA and the breakdown voltage over 5 V.

Adaptive Reversal Tree Protocol with Optimal Path for Dynamic Sensor Networks

  • Hwang, Kwang-Il
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.32 no.10A
    • /
    • pp.1004-1014
    • /
    • 2007
  • In sensor networks, it is crucial to reliably and energy-efficiently deliver sensed information from each source to a sink node. Specifically, in mobile sink (user) applications, due to the sink mobility, a stationary dissemination path may no longer be effective. The path will have to be continuously reconfigured according to the current location of the sink. Moreover, the dynamic optimal path from each source to the sink is required in order to reduce end-to-end delay and additional energy wastage. In this paper, an Adaptive Reversal Optimal path Tree (AROT) protocol is proposed. Information delivery from each source to a mobile sink can be easily achieved along the AROT without additional control overhead, because the AROT proactively performs adaptive sink mobility management. In addition, the dynamic path is optimal in terms of hop counts and the AROT can maintain a robust tree structure by quickly recovering the partitioned tree with minimum packet transmission. Finally, the simulation results demonstrate that the AROT is a considerably energy-efficient and robust protocol.

Accuracy of Current Delivery System in Current Source Data-Driver IC for AM-OLED

  • Hattori, Reiji
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.4 no.4
    • /
    • pp.269-274
    • /
    • 2004
  • Current delivery system, in which the analog current produced by a unique DAC circuit is stored into a current-memory circuit and delivered in a time-divided sequence, shows variation of output current as low as 4% in a current source data-driver IC for AM-OLED driven by a current-programmed method without any fuse repairing after fabrication. This driver IC has 54 outputs and can sink constant current as low as 3 ${\mu}A$ with 6-bit analog levels. Such a low current level without variation can hardly be obtained by an ordinary MOS transistor because the current level is in the sub-threshold region and changes exponentially with threshold voltage variation. Thus we adopted a current mirror circuit composed of bipolar transistors to supply well-controlled current within a nano-ampere range.

Study on Thermal Characteristics of Smart LED Driver ICs Package (일체형 스마트 LED Driver ICs 패키지의 열 특성 분석)

  • Kang, Ey Goo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.29 no.2
    • /
    • pp.79-83
    • /
    • 2016
  • This research was analyzed thermal characteristics that was appointed disadvantage when smart LED driver ICs was packaged and we applied extracted thermal characteristics for optimal layout design. We confirmed reliability of smart LED driver ICs package without additional heat sink. If the package is not heat sink, we are possible to minimize package. For extracting thermal loss due to overshoot current, we increased driver current by two and three times. As a result of experiment, we obtained 22 mW and 49.5 mW thermal loss. And we obtained optimal data of 350 mA driver current. It is important to distance between power MOSFET and driver ICs. If thhe distance was increased, the temperature of package was decreased. And so we obtained optimal data of 3.7 mm distance between power MOSFET and driver ICs. Finally, we fabricated real package and we analyzed the electrical characteristics. We obtained constant 35 V output voltage and 80% efficiency.

Development of Switching Power Module with Integrated Heat Sink and with Mezzanine Structure that Minimizes Current Imbalance of Parallel SiC Power Semiconductors (SiC 전력반도체의 병렬 구동 시 전류 불균형을 최소화하는 Mezzanine 구조의 방열일체형 스위칭 모듈 개발)

  • Jeong-Ho Lee;Sung-Soo Min;Gi-Young Lee;Rae-Young Kim
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.28 no.1
    • /
    • pp.39-47
    • /
    • 2023
  • This paper applies a structural technique with uniform parallel switch characteristics in gates and power loops to minimize the ringing and current imbalance that occurs when a general discrete package (TO-247)-based power semiconductor device is operated in parallel. Also, this propose a heat sink integrated switching module with heat sink design flexibility and high power density. The developed heat dissipation-integrated switching module verifies the symmetry of the parasitic inductance of the parallel switch through Q3D by ansys and the validity of the structural technique of the parallel switch using the LLC resonant converter experiment operating at a rated capacity of 7.5 kW.

Comparative Analysis of Heat Sink Performance At 1U Rack Mountable Server (1U 렉마운터블 서버에서의 힛싱크 성능에 대한 비교 분석)

  • Shin, Jung-Yong;Lee, In-Ho
    • Proceedings of the KSME Conference
    • /
    • 2004.11a
    • /
    • pp.1472-1475
    • /
    • 2004
  • Current processor power consumption has dramatically increased and already reached 115 Watts. Therefore, Heat sink design needs more high accuracy in 1U server. The target performance of heat sink is very dependent of fin geometry and it is also seriously affected by design conditions such as fan type, air duct shape and heatsink design parameters. The present paper investigates the behavior of heat sink performance under various conditions. The present work addresses pressurized type plane fin heat sinks having dimension of 40 mm by 40 mm by 56 mm fan.

  • PDF

Efficient Mobile Sink Location Management Scheme Using Multi-Ring in Solar-Powered Wireless Sensor Networks

  • Kim, Hyeok;Kang, Minjae;Yoon, Ikjune;Noh, Dong Kun
    • Journal of the Korea Society of Computer and Information
    • /
    • v.22 no.10
    • /
    • pp.55-62
    • /
    • 2017
  • In this paper, we proposes a multi-ring based mobile sink location scheme for solar-powered wireless sensor network (WSN). The proposed scheme maintains the multi-rings in which nodes keep the current location of sink node. With the help of nodes in multi-rings, each node can locate the sink node efficiently with low-overhead. Moreover, because our scheme utilizes only surplus energy of a node, it can maintain multiple rings without degrading any performance of each node. Experimental results show that the proposed scheme shows much better latency and scalability with lower energy-consumption than the existing single-ring based scheme.

Heat Pipe Heat Sink Development for Electronics Cooling (전자냉각용 히트파이프 히트싱크 개발)

  • 이기우;박기호;이석호;유성연
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.14 no.8
    • /
    • pp.664-670
    • /
    • 2002
  • A heat sink (HS) system using heat pipes for electronics systems was studied. The experimental results indicate that a cooling capacity of up to 150w at an overall temperature difference of $50^{\circ}C$ can be attainable. The heat sink design program also showed that a computer simulation can predict the most of the parameters involved. To do so, however, the interior temperature distribution had to be verified by experimental results. The current simulation results were close to the experimental results in acceptable range. The simulation study showed that the design program can be a good tool to predict the effects of various parameters involved in the optimum design of the heat sink.

DC Characteristics of AlGaN/GaN HFETs Using the Modeling of Piezoelectric and Thermal Effects (Piezoelectric효과와 열 효과 모델링을 고려한 AlGaN/GaN HFET의 DC 특성)

  • Park, Seung-Wook;Hwang, Woong-Joon;Shin, Moo-Whan
    • Korean Journal of Materials Research
    • /
    • v.13 no.12
    • /
    • pp.769-774
    • /
    • 2003
  • In this paper, we report on the DC characteristics of the AlGaN/GaN HFETs using physical models on piezoelectric and thermal effects. Employing the models was found to be essential for a realistic prediction of the DC current-voltage characteristics of the AlGaN/GaN HFETs. Though use of the implementation of the physical models, peak drain current, transconductance, pinch-off voltage, and most importantly, the negative slope in the current were accurately predicted. The importance of the heat sink effect was demonstrated by the comparison of the DC characteristics of AlGaN/GaN HFETs fabricated from different substrates including sapphire, Si and SiC. Highest peak current was achieved from the device with SiC by an effective suppression of heat sink effect.