• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.1
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• pp.70-77
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• 2005

A new converter to transfer energy from a low-voltage AC current source to a battery is proposed. It is focused to find operational modes of the converter. The low-voltage AC current source is an equivalent of the piezoelectric generator, which converts the mechanical energy to the electric energy. The converter consists of a full-bridge MOSFET rectifier and a MOSFET boost converter in order to make the converter small and efficient. The operational principle and modes of the converter are investigated with the consideration of effects of the parasitic capacitances of MOSFETs and diode. The results are proved with simulation studies using PSIM and Pspice.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.196-198
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• 2007

A circuit design technique to reduce the propagation time is proposed for the analog parallel processing-based Viterbi decoder. The analog Viterbi decoder implements the function of the conventional digital Viterbi decoder utilizing the analog parallel processing circuit technology. The decoder is for the PR(1.2,2.1) signal of DVD. The benefits are low power consumption and less silicon occupation. In this paper, a propagation time reduction technique is proposed by minimizing the parasitic capacitance components in the layout design of the analog Viterbi decoder. The propagation time reduction effect of the proposed technique has been shown via HSPICE simulation.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2151-2155
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• 1998

The traveling wave type ultrasonic motor(USM) has no electro-magnetic circuits( coil or core). The driving principle of the USM is based on high-frequency mechanical vibrations and frictional force. The USM, thus, is fed by two-phase high - frequency sinusoidal inverter using its series resonant parasitic components. For the using of series resonant type inverter, it should be needed to a USM parasitic capacitance and a proper inductor chosen. In this paper, the values of optimal inductance are designed and the efficiency of USM drives is achieved. The effectiveness of the proposed design is demonstrated by experiments.

• Journal of Power Electronics
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• v.9 no.1
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• pp.18-25
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• 2009

Conventional series-resonant pulse frequency modulation controlled DC-DC high power converters with a high-frequency transformer link which is designed for driving the high power microwave generator has the problem of hard switching commutation at turn-on and turn-off of active power switching devices. This problem is due to the influence of the magnetizing current of the high-frequency transformer. This paper presents a novel prototype for a high-frequency transformer using parasitic parameters with a lossless inductive snubber and a series resonant capacitor assisted series-resonant zero current switching pulse frequency modulated DC-DC power converter, which is designed using a high power magnetron for microwave ovens. In order to implement a complete and efficient soft switching commutation, the performance of the new converter topology is practically confirmed and evaluated in the prototype of a power microwave generator.

• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.938-944
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• 2013

In this paper, we propose a method for suppressing shaft voltage by modifying the shape of the rotor and the permanent magnets in interior permanent magnet-type-high-voltage motors. Shaft voltage, which is induced by parasitic components and the leakage flux in motor-driven systems, adversely affects their bearings. In order to minimize shaft voltage, we designed a magnet rearrangement and rotor re-structuring of the motor. The shaft voltage suppression effect of the designed model was confirmed experimentally and by comparative finite element analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.4
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• pp.71-78
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• 2005

This paper proposes a novel multi-level energy recovery sustaining driver for AC PDP(Plasma Display Panel), which solves the problems of the conventional multi-level sustaining driver. While the conventional circuit improves the voltage md current stress of the switching elements in Weber circuit not only there are parasitic resonant currents between resonant inductors and parasitic capacitance and hard switching, but also the changing period between 0 and sustain voltage is too long. Comparing the proposed circuit with the conventional circuit, the number of components are reduced and the parasitic resonant currents in resonant inductors are eliminated Moreover the hard switching problem is solved by using CIM(Current Injection Method) and the operating frequency will be high as much as possible by removing Vs/2 sustain period. And the circuit operations of the proposed circuit are analyzed for each mode and the validity is verified by the simulations using PSpice program.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.79-84
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• 2007

Recently it is strongly required to develop the better fuel economy as well as basic power performance based on strict emission legislation. This paper focuses on studies of the engine cooling and ancillaries system among fuel economy factors in the developing stage. Firstly through the analysis of the current specifications, it is assessed whether each components may be designed properly, not overdesigned. Secondly, it is predicted how the fuel economy of each components can be improved. Finally the results are confirmed by vehicle field test equppted with the updatedcomponents. This study found good agreementbetween the prediction and the field test on the vehicle fuel economy improvements of the heavy duty engine vehicle with updated components such as engine cooling and ancilliaries.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.11
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• pp.25-31
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• 2016

Parasitic capacitance and resistance of FinFET transistors are the important components that determine the frequency performance of the circuit. Therefore, the researchers in our group developed more accurate parasitic capacitance and resistance for FinFETs than BSIM-CMG. To verify the RF performance, proposed model was applied to design an LNA that has $S_{21}$ more than 10dB and center frequency more than 60GHz using HSPICE. To verify the accuracy of the proposed model, mixed-mode capability of 3D TCAD simulator Sentaurus was used. $S_{21}$ of LNA was chosen as a reference to estimate the error. $S_{21}$ of proposed model showed 87.5% accuracy compared to that of Sentaurus in 10GHz~100GHz frequency range. The $S_{21}$ accuracy of BSIM-CMG model was 56.5%, so by using the proposed model, the accuracy of the circuit simulator improved by 31%. This results validates the accuracy of the proposed model in RF domain and show that the accuracies of the parasitic capacitance and resistance are critical in accurately predicting the LNA performance.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.501-504
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• 2000

In this paper the PC power supply is studied from the point of system stability. The power stage model of a multiple output forward converter with weighted voltage mode control is derived including all the major parasitic components and the small signal model is also derived. Determination of the weighting factors and a design procedure for the loop compensation are presented. Finally the model is verified through the simulation of three output forward converter with SABER.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1512-1515
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• 1987

The buffer circuit having minimum delay time is designed and analyzed in this paper. Considering the parasitic components of the MOS transistor, the optimal transistor size ratio between the individual buffer stages is presented. This paper's result is better than that of the Mead and Conway's analysis [1] with respect to both delay time and total area that buffer occupies.