• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.9
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• pp.431-436
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• 2005

This paper studies a novel boost DC-DC converter operated high efficiency for discontinuous current mode (DCM) control. The converter worked in DCM eliminates the complicated circuit control requirement, reduces a number of components, and reduces the used reactive components size. In the general DCM converter, the switching devices are turned-on the zero current switching (ZCS), and the switching devices must be switched-off at a maximum reactor current. To achieve the zero voltage switching (ZVS) at the switching turn-off, the proposed converter is constructed by using a new loss-less snubber circuit. Soft-switched operation of the proposed boost converter is verified by digital simulation and experimental results. A new boost converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses. The result is that the switching loss is very low and the efficiency of boost DC-DC converter is high.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.99.2-99
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• 2001

An electronically tunable current-mode second-order multifunctional filter is described in this paper. The proposed filter consists of two four-terminal floating nullors (FTFNs), two dual-output OTAs and two grounded capacitors. The circuit can simultaneously realize the lowpass, bandpass and highpass current transfer functions from the same configuration without changing the circuit configuration and elements. The natural angular frequency we and the parameter wo/Q can be orthogonally controlled through adjusting the transconductance gain of OTA. PSPICE simulation results are employed to confirm the circuit performance.

• Journal of Welding and Joining
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• v.16 no.4
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• pp.39-46
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• 1998

$CO_2$ gas shielded arc welding has been characterized with its harsh arc compared to Ar-based shielding gases and with its high level of spattere specially in welding current range of 250~300 amperes. In this range of welding current, the metal transfer mode showed to be changed from short circuit to globular with the increase of welding voltage resulting in so-called the transitional mode in which both modes of transfer appeared together. To characterize the transitional mode, the short circuit events were divided into two groups, i.e. normal short circuit (N.S.C) which has short circuit time $(t_s)$ over 2msec and instantaneous short circuit (I.S.C) of $t_s$$\leq$2msec. The experimental results showed that the number of N.S.C decreased almost linearly with the increase of welding voltage and appeared to be not related with spatter generation rate. However I.S.C became to be pronounced in the transitional condition and its number reached the maximum value at around 29.0 volts. Considering the relation with the spatter generation rate, it was found that the number of I.S.C had a very strong correlation with the spatter generation rate of the transitional condition. It was further demonstrated that spatter generation rate decreased quite linearly with the decrease of I.S.C frequency. It implies that I.S.C is the most important waveform factor controlling the spatter generation of the transitional mode, i.e. in the middle range of welding current. Based on these results, It was discussed that in the transitional mode the basic concept of waveform control for suppressing spatter generation would be different from the one applied for typical short circuit transfer mode of low welding current.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.275-278
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• 2003

This paper presents a full-adder using current-mode multiple valued logic CMOS circuits. This paper compares propagation delay, power consumption, and PDP(Power Delay Product) compared with conventional circuit. This circuit is designed with a samsung 0.35um n-well 2-poly 3-metal CMOS technology. Designed circuits are simulated and verified by HSPICE. Proposed full-adder has 2.25 ns of propagation delay and 0.21 mW of power consumption.

• Journal of IKEEE
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• v.14 no.2
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• pp.1-8
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• 2010

In this paper, Green Mode Power IC is designed to reduce the standby power. The proposed and designed IC works for the Switch Mode Power Supply(SMPS) and has the function of PWM. To reduce the unnecessary electric power, burst mode and skip mode section are introduced and controlled by external power MOSFET to diminish the standby power. The proposed IC is designed and simulated by KEC 30V-High Voltage 0.5um CMOS Process. The structure of proposed IC is composed of voltage regulator circuit, voltage reference circuit, UVLO(Under Voltage Lock out) circuit, Ibias circuit, green circuit, PWM circuit, OSC circuit, protection circuit, control circuit, and level & driver circuit. Measuring the current consumption of each block from the simulation results, 1.2942 mA of the summing consumption current from each block is calculated and ot proved that it is within the our design target of 1.3 mA. The current consumption of the proposed IC in this paper is less than a half of conventional ICs, and power consumption is reduced to the extent of 1W in standby mode. From the above results, we know that efficiency of proposed IC is superior to the previous IC.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.186-190
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• 2000

This paper propose a "Active common-mode voltage damper circuit" that capable of a suppression of a common-mode voltage produced in the PWM VSI. The four level half-bridge PWM inverter circuit and common-mode transformer are incorporated into the "Active common-mode voltage damper" the design method of which is presented Effect of "Active common-mode voltage damper" in this paper verifies a propriety and effectiveness in 2.2[kW] induction motor drive using IGBT inverter. Experimental results show that "common-mode voltage damper" makes contributions to reducing a high frequency leakage current and common-mode voltage.leakage current and common-mode voltage.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.4
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• pp.55-61
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• 1994

The multiple valued logic(MVL) circuit with ROM type using current mode CMOS is presented in this paper. This circuit is composed of the multiple valued-to-binary(MV/B) decoder and the selection circuit. The MV/B decoder decodes the single input multiple valued signal to N binary signal, and the selection circuits is composed N$\times$N array of the selecion cells with ROM types. The selection cell is realized with the current mirror circuits and the inhibit circuits. The presented circuit is suitable for designing the circuit of MVL functions with independent variables, and reduces the number of selection cells for designing the circuit of symmetric MVL functions as many as {($N^2$-N)/2}+N. This circuit possess features of simplicity. expansibility for array and regularity, modularity for the wire routing. Also, it is suitable for VLSI implementation.

• Journal of IKEEE
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• v.17 no.1
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• pp.77-82
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• 2013

In this paper, dc-dc buck converter controled by the peak current-mode pulse-width-modulation (PWM) presented. Based on the small-signal model, we propose the novel methods of the power stage and the systematic stability designs. To improve the reliability and performance, over-temperature and over-current protection circuits have been designed in the dc-dc converter systems. To prevent electrostatic An electrostatic discharge (ESD) protection circuit is proposed. The proposed dc-dc converter circuit exhibits low triggering voltage by using the gate-substrate biasing techniques. Throughout the circuit simulation, it confirms that the proposed ESD protection circuit has lower triggering voltage(4.1V) than that of conventional ggNMOS (8.2V). The circuit simulation is performed by Mathlab and HSPICE programs utilizing the 0.35um BCD (Bipolar-CMOS-DMOS) process parameters.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.529-530
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• 2006

An efficient sensing scheme adoptable in DC-DC converter is described. The output voltage of the whole DC-DC converter is fed back to the input voltage of the sensor. The comparison in the sensor is accomplished by a current push-pull action. With a fixed reference, the comparator can be embodied based on (W/L) ratios. The current-mode scheme benefits the system better than a conventional voltage-mode one in terms of small area, low power consumption.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2570-2578
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• 2010

This paper presents a digital-controlled single-phase power-factor correction (PFC) converter operating in critical current conduction mode. The proposed converter utilizes the DC-DC boost converter topology for the PFC and operates the inductor current in critical conduction mode. Because the proposed converter is controlled digitally using a micom, its control circuit is simplified and the converter operates more effectively. This paper first explains the operational principles of the proposed converter and then analyzes the converter circuit. And this paper explains the implementation method of proposed converter with a detail design example, which is divided into software and circuit design parts. Also, it is shown through the experimental results of the prototype converter by the designed circuit parameters that the proposed converter has good performance as a single-phase PFC converter.