• Title/Summary/Keyword: Logic circuits

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A Fault Simulator for IDDQ Testing (IDDQ 테스트를 위한 고장 시뮬레이터)

  • 배성환;김대익;이창기;전병실
    • The Journal of the Acoustical Society of Korea
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    • v.18 no.1
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    • pp.92-96
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    • 1999
  • As CMOS technologies have been rapidly developed, bridging faults have been relatively increased. IDDQ testing is a current testing methodology which can enhance reliability of the circuit since it efficiently detects bridging faults that are difficult to detect by functional testing. In this paper we consider internal bridging faults occurred in each gate of logic circuits under test and finally develop a fault simulator for IDDQ testing to detect assumed bridging faults.

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A Study on Short Channel Effects of n Channel Polycrystalline Silicon Thin Film Transistor Fabricated at High Temperature (고온에서 제작된 n채널 다결정 실리콘 박막 트랜지스터의 단채널 효과 연구)

  • Lee, Jin-Min
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.5
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    • pp.359-363
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    • 2011
  • To integrate the sensor driver and logic circuits, fabricating down scaled transistors has been main issue. At this research, short channel effects were analyzed after n channel polycrystalline silicon thin film transistor was fabricated at high temperature. As a result, on current, on/off current ratio and transconductance were increased but threshold voltage, electron mobility and s-slope were reduced with a decrease of channel length. When carriers that develop at grain boundary in activated polycrystalline silicon have no gate biased, on current was increased with punch through by drain current. Also, due to BJT effect (parallel bipolar effect) that developed under region of channel by increase of gate voltage on current was rapidly increased.

Controllability of Threshold Voltage of ZnO Nanowire Field Effect Transistors by Manipulating Nanowire Diameter by Varying the Catalyst Thickness

  • Lee, Sang Yeol
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.3
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    • pp.156-159
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    • 2013
  • The electrical properties of ZnO nanowire field effect transistors (FETs) have been investigated depending on various diameters of nanowires. The ZnO nanowires were synthesized with an Au catalyst on c-plane $Al_2O_3$ substrates using hot-walled pulsed laser deposition (HW-PLD). The nanowire FETs are fabricated by conventional photo-lithography. The diameter of ZnO nanowires is simply controlled by changing the thickness of the Au catalyst metal, which is confirmed by FE-SEM. It has been clearly observed that the ZnO nanowires showed different diameters simply depending on the thickness of the Au catalyst. As the diameter of ZnO nanowires increased, the threshold voltage of ZnO nanowires shifted to the negative direction systematically. The results are attributed to the difference of conductive layer in the nanowires with different diameters of nanowires, which is simply controlled by changing the catalyst thickness. The results show the possibility for the simple method of the fabrication of nanowire logic circuits using enhanced and depleted mode.

An Intelligent Fire Detection Algorithm for Fire Detector

  • Hong, Sung-Ho;Choi, Moon-Su
    • International Journal of Safety
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    • v.11 no.1
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    • pp.6-10
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    • 2012
  • This paper presents a study on the analysis for reducing the number of false alarms in fire detection system. In order to intelligent algorithm fuzzy logic is adopted in developing fire detection system to reduce false alarm. The intelligent fire detection algorithm compared and analyzed the fire and non-fire signatures measured in circuits simulating flame fire and smoldering fire. The algorithm has input variables obtained by fire experiment with K-type thermocouple and optical smoke sensor. Also triangular membership function is used for inference rules. And the antecedent part of inference rules consists of temperature and smoke density, and the consequent part consists of fire probability. A fire-experiment is conducted with paper, plastic, and n-heptane to simulate actual fire situation. The results show that the intelligent fire detection algorithm suggested in this study can more effectively discriminate signatures between fire and similar fire.

ALU Design of CMOS Single Chip Microcomputer (CMOS 단일칩 마이크로 컴퓨터의 ALU 설계)

  • Park, Yong-Su;Ryou, Gee-Chul;Kim, Tae-Gyung;Chung, Ho-Sun;Lee, Wu-Il
    • Proceedings of the KIEE Conference
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    • 1987.07b
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    • pp.1481-1484
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    • 1987
  • The ALU of CMOS microcomputer have been designed with the 3um design rule for CMOS polysilicon gate and Its cells were layed out. The operation of circuits were simulated with EDAS_P. The widths and lengths of gates In the circuit were determined using SPlCE. The carry delay of the ALU was Improved by Manchester carry method. The results of logic and circuit simulation were in good agreement with expected circuit characteristics.

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Functional Simulation of Logic Circuits by Prolog (Prolog를 이용한 논리회로의 기능적 시뮬레이션)

  • Kim, J.S.;Cho, S.B.;Park, H.J.;Lim, I.C.
    • Proceedings of the KIEE Conference
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    • 1987.07b
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    • pp.1467-1470
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    • 1987
  • This paper proposes a functional simulation algorithm which decrease the internal memory space and run time in simulation of VLSI. Flip-flop, register, ram, rom, ic and fun are described as functional elements in the simulator. Especially icf is made as new functional element by combining the gate and the functional element, therefore icf is used efficiently in simulation of VLSI. The proposed algorithm is implemented on PC-AT(MS-DOS) in by Prolog-1.

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Array of SNOSFET Unit Cells for the Nonvolatile EEPROM (비휘방성 EEPROM을 위한 SNOSFET 단위 셀의 어레이)

  • 강창수;이형옥;이상배;서광열
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1991.10a
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    • pp.48-51
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    • 1991
  • Short channel Nonvolatile EEPROM memory devices were fabricated to CMOS 1M bit design rule, and reviews the characteristics and applications of SNOSFET. Application of SNOS field effect transistors have been proposed for both logic circuits and nonvolatile memory arrays, and operating characteristics with write and erase were investigated. As a results, memory window size of four terminal devices and two terminal devices was established low conductance stage and high conductance state, which was operated in “1” state and “0”state with write and erase respectively. And the operating characteristics of unit cell in matrix array were investigated with implementing the composition method of four and two terminal nonvolatile memory cells. It was shown that four terminal 2${\times}$2 matrix array was operated bipolar, and two termineal 2${\times}$2 matrix array was operated unipolar.

Design of A On-Chip Caches for RISC Processors (RISC 프로세서 On-Chip Cache의 설계)

  • 홍인식;임인칠
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.8
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    • pp.1201-1210
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    • 1990
  • This paper proposes on-chip instruction and data cache memories on RISC reduced instruction set computer) architecture which supports fast instruction fetch and data read/write, and enables RISC processor under research to obtain high performance. In the execution of HLL(high level language) programs, heavily used local scalar variables are stored in large register file, but arrays, structures, and global scalar variables are difficult for compiler to allocate registers. These problems can be solved by on-chip Instruction/Data cache. And each cycle of instruction fetch, pad delay causes the lowering of the processors's performance. Cache memories are designed in CMOS technology and SRAM(static-RAM), that saves layout area and power dissipation, is used for instruction and data storage. To speed up and support RISC processor's piplined architecture efficiently, hardwired logic technology is used overall circuits i cache blocks. The schematic capture and timing simulation of proposed cache memorises are performed on Apollo DN4000 workstation using Mentor Graphics CAD tools.

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Microprocessor Control in D-4 Channel Bank (D-4PCM 단말장치에의 마이크로프로세서 응용)

  • 송상훈;김영균
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.16 no.6
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    • pp.40-47
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    • 1979
  • In the recent developent of D-4 Channel Bank which is the basic PCM multiplex terminal, we utilized the one-chip microprocessor in the design of the Alarm and Trunk processing unit besides we could add more flexible functions, we simplified the logic circuits and the discrete parts. Since in Korea, we are lacking in the semiconductor technology, the microprocessor applications in the communication systems desist give us the meaningful advantages in the a aspects of economy, reliability and new technology.

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Approximate-SAD Circuit for Power-efficient H.264 Video Encoding under Maintaining Output Quality and Compression Efficiency

  • Le, Dinh Trang Dang;Nguyen, Thi My Kieu;Chang, Ik Joon;Kim, Jinsang
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.5
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    • pp.605-614
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    • 2016
  • We develop a novel SAD circuit for power-efficient H.264 encoding, namely a-SAD. Here, some highest-order MSB's are approximated to single MSB. Our theoretical estimations show that our proposed design simultaneously improves performance and power of SAD circuit, achieving good power efficiency. We decide that the optimal number of approximated MSB's is four under 8-bit YUV-420 format, the largest number not to affect video quality and compression-rate in our video experiments. In logic simulations, our a-SAD circuit shows at least 9.3% smaller critical-path delay compared to existing SAD circuits. We compare power dissipation under iso-throughput scenario, where our a-SAD circuit obtains at least 11.6% power saving compared to other designs. We perform same simulations under two- and three-stage pipelined architecture. Here, our a-SAD circuit delivers significant performance (by 13%) and power (by 17% and 15.8% for two and three stages respectively) improvements.