• Proceedings of the KSR Conference
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• 2000.05a
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• pp.336-343
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• 2000

This paper proposes the failsafe control logic. which has applied to the voting on the TMR system by using FPGA The self-detection circuit is also designed for detecting a characteristic of fault at TMR system. The fault producing in the self-detection system is largely classified among an intermittent fault, a transient fault and a permanent fault. If it is happened to the permanent fault, the system can be failed. Therefore, it is designed the logic circuit which is not transferred the permanent fault to the system after shut off output. The control logic of the Fail Safe proposed in the paper is required for a circuit integrate of device to minimize the failure happened. Therefore, it makes to design FPGA with modeling of VHDL. The circuit of the Fail Safe of TMR system is able to apply to nuclear system, rail-way system, aerospace and aircraft system which is required for high reliability.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.1-9
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• 1996

In the following paper, new architectural algorithm of clock and data recovery circuit is proposed for 622.08 Mbps optical communication receiver. New algorithm makes use of charge pump PLL using voltage controlled ring oscillator and extracts 8-channel 77.76 MHz clock signals, which are delayed by i/8 (i=1,2, ...8), to convert and recover 8-channel parallel data from 662.08 Mbps MRZ serial data. This circuit includes clock genration block to produce clock signals continuously even if input data doesn't exist. And synchronization of data and clock is doen by the method which compares 1/2 bit delayed onput data and decided dta by extracted clock signals. Thus, we can stabilize frequency and phase of clock signal even if input data is distorted or doesn't exist and simplify receiver architecture compared to traditional receiver's. Also it is possible ot realize clock extraction, data decision and conversion simulataneously. Verification of this algorithm is executed by DESIGN CENTER (version 6.1) using test models which are modelized by analog behavior modeling and digital circuit model, modified to process input frequency sufficiently, in SPICE.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.1
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• pp.1-8
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• 2008

A dynamic model for II-SEPIC(Isolated Inverse-SEPIC) is developed based on the state-space averaging method and its control characteristics are investigated in this paper. Equations for circuit design of II-SEPIC are derived through steady state analysis and the resulted circuit parameters are used in the consequent simulation and experiment works. A structure of control system is devised to obtain better control performance. In order to verify validity and effectiveness of the design equations and dynamic model derived, dynamic control responses of II-SEPIC system against line and load variation are illustrated in both simulation and experiment.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.9
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• pp.1308-1316
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• 1989

A simplified 10-element GaAs MESFET equivalent circuit model has been presented which is suitable for the design of ultrabroad-band microwave small-signal amplification, the these circuit element values are extracted from measured S-parameters using complex-curve fitting algorithm. Packaged GaAs MESFET equivalent circuits are composed of intrinsic \ulcornermodel and several extrinsic elements at microwave frequencies, of which the largest effects are caused by package lead inductances. If these are eliminated from measured S-parameters, newly obtained S-parameters are closed to intrinsic \ulcornermodel, and the rest element values can be easily extracted. The modeling results applied to the packaged GaAs MESFET NE71083 are almost equal between the measure S-parameters and the mideled S-parameters within b 2% errors from DC to 8GHz, and errors are increased to \ulcorner% upto 12GHz wide bandwidth.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.12
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• pp.49-57
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• 2001

In this paper, equivalent circuit model and novel model parameter extraction method of a silicon(Si) substrate are presented. Substrate coupling through Si-substrate is quantitatively investigated by analyzing equivalent circuit with operating frequency and characteristic frequencies (i.e., pole and zero frequency) of a system. For the experimental verification of the equivalent circuit and parameter extraction method, test patterns are designed and fabricated in standard CMOS technology with various isolation distances, substrate resistivity, and guard-ring structures. Then, these are measured in l00MHz-20GHz frequency range by using vector network analyzer. It is shown that the equivalent-circuit-based HSPICE simulation results using extracted parameters have excellent agreement with the experimental results. Thus, the proposed equivalent circuit and parameter extraction methodology can be usefully employed in mixed-signal circuit design and verification of a circuit performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.6
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• pp.42-50
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• 2006

This paper addresses the optimized thermal modeling methodology for spacecraft board level thermal analysis. A direct thermal modeling of external and internal structure of active parts which have high power dissipation is newly proposed, based on conventional plate modeling for Printed Circuit Board(PCB). The parts thermal modeling results were compared with other generic methodologies and verified by thermal vacuum test. This parts thermal modeling was directly applied to thermal analysis of CS(Communication Subsystem) board of HAUSAT-2 small satellite. As a result, it was confirmed that the parts thermal modeling can complement other conventional modeling methodologies. A parts thermal modeling is very effective for thermal control design, since the existing thermal problems can be solved at the parts level in advance.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.4
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• pp.24-31
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• 2011

Double-color Injection molding machine is the assembly of many kinds of mechanical, fluid power part and electric electronic control system. From in these, fluid power is a part where becomes the first core of this machine. Fluid power systems of double-color injection molding machine are modelled and analyzed using a commercial program AMESim. Partial system models which is divided according to functional operation are made and its analysis results shows how design parameters work on operational characteristics like pressure, flow rates, displacement at each node and so on. Analysis modeling and compared the data which gets from experiment and the analysis result which has a reliability got data. The results made by analysis will be used design of fluid power circuit for developing a double-color injection molding machine.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.628-634
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• 1995

In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformer which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backash and friction. Therefore a dynamic modeling and stste sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensitivity snalysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensitivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design based on the results on the results of dynamic and state sensitivity.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1993.10a
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• pp.71-75
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• 1993

The Modeling analysis and design of a high frequency LC-type series and LLCC-type parallel resonant converter oprating in the continous conduction is presented. The state-plane diagram representation of the converter response gives and good insight into the converter operation. A set of characterisric frequency are plotted which design parameters can be obtained.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.2
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• pp.161-167
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• 2015

In this paper, a novel thermoelectric cooling system utilizing condensed water is introduced and its electrical equivalent circuit model is proposed. The introduced system can deals with the condensed water and improves efficiency by spraying the condensed water on heat sink. The electrical equivalent circuit model is derived by combining the circuit model of the classical thermoelectric cooling system with equation of heat exchange. Because the parameters of the model can be defined from not other experimental data but just the data sheet of the thermoelement, the model can be useful to design and develop the controller of the proposed system. We verify that the proposed model is valid and the introduced system is more efficient than the previous thermoelectric cooling system through simulations.