• Journal of IKEEE
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• v.19 no.3
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• pp.304-310
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• 2015

A SCALDO(Supercapacitor Assisted LDO) regulator is a new regulator having advantages of a SMPS(Switch Mode Power Supply) which has a good efficiency and a LDO(Low Drop-out) regulator which has stable output characteristics and good EMI(Electro Magnetic Interference) characteristics. However, a conventional SCALDO regulator needs a lot of power consumption to control its switches and it drops an efficiency of the circuit. In this paper, to reduce switching power consumption and improve an efficiency of the circuit, a new SCALDO regulator adopting MOSFETs as its switching parts is proposed and it is found out that the proposed SCALDO regulator has the maximum 9.5% higher efficiency than the conventional SCALDO regulator. We also try to simplify production process of the circuit by changing switching control method of the circuit from MCU(Micro-controller unit) based firmware control to hardware control using a comparator and a T-F/F(Flip Flop).

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1954-1956
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• 2005

본 논문에서는 SMPS(Switch-Mode Power Supply)의 역률을 개선할 수 있는 power factor correction(PFC) IC를 설계하였다. 설계된 PFC IC에는 전원장치의 power MOSFET을 구동할 수 있는 기능 이외에도 과전압, 과전류 및 단락보호 기능이 포함되어 있다. 또한 시스템이 대기상태에 있는 경우, 전압 및 전류 feedback 제어에 의해 효과적으로 대기전력을 절감할 수 있도록 설계하였다. 설계된 PFC IC는 시스템이 대기상태에서 일정시간동안 부하변동이 없을 경우 이를 감지하여 자동으로 시스템을 off 시켜 대기전력 소모를 최소화 하는 기능을 포함하고 있다.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.97-105
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• 2020

Recently, as the data speed and operating frequencies of Ethernet keeps increasing, electro magnetic interference (EMI) also becomes increasing. The generation of such EMI will cause malfunction of near electronic devices. In this study, EMI filters were applied to reduce the EMI generated by DC-DC SMPS (switching mode power supply), which is the main cause of EMI generation of Ethernet switch. As the EMI filter, MLCCs with excellent withstanding voltage characteristics were used, which had advantages in miniaturization and mass production. Two types of EMI MLCC filters were used, which are X-capacitor and X, Y-capacitor. X-capacitor was composed of 2 MLCCs with 10 nF and 100 nF capacity and 1 Mylar capacitor. Y-capacitor was consisted of 6 MLCCs with a capacity of 27 nF. When only X-capacitor was applied as EMI filter, the conductive EMI field strength exceeded the allowable limit in frequency range of 150 kHz ~ 30 MHz. The radiative EMI also showed high EMI strength and very small allowable margin at the specific frequencies. When the X and Y-capacitors were applied, the conductive EMI was greatly reduced, and the radiation EMI was also found to have sufficient margin. In addition, X, Y-capacitors showed very high insulation resistance and withstanding resistance performances. In conclusion, EMI X, Y-capacitors using MLCCs reduced the EMI noise effectively and showed excellent electrical reliability.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.12
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• pp.624-630
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• 2001

The trend of the regulations on environmental issues are getting tight. Responding to this trend new technologies such as moving electrodes, wide pitch and pulsed power supply are also introduced in the electrostatic precipitator(EP) systems. The introduction of wide pitch and moving electrodes enhances the system performance of the EPs by improving air-flow and by improving the ash reentrainment on rapping. The power supplies for the EPs developed up to date include thyristor-based dc or intermittent type, SMPS(switching mode power supply) type and the pulsed-power supply type. The use of the pulsed ones is known to improve dust-collecting efficiency of high resistivity ash and reduces back corona occurrence in the collecting plate. There are two kinds of pulsed-power supplies; one with pulsed transformers and the other with direct dc switching devices. The latter uses rotary spark gap switches or semiconductor switches. Both have the merits and demerits: the spark gap switches are simple and robust but has short life time, hence, high maintenance cost, whereas the semiconductor switches have long life time but are costly. In this study, A high voltage power supply with superimposing voltage pulse on dc source was developed for EPs. This study describes circuit topology, operating principle of the scheme, and analysis of experimental results on Dong-Hae Power Plant. The pulsed power supply consists of a variable dc power supply with ratings of 60kV, 800mA and pulse generator which is made of high voltage thyristor-diode switch strings, an LC resonant tank and a blocking inductor. The pulse generator generates variable pulse-voltage up to 70kV using a high frequency resonant inverter with a variable dc source. Two prototypes were built and tested on 250MW DongHae power plant to verify the possibility of the commercial use and the normal operation in the transient states.

• Journal of IKEEE
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• v.8 no.1 s.14
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• pp.152-159
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• 2004

In this study, we design the one-chip PWM IC with high voltage power switch (300V class LDMOSFET) for SMPS (Switching Mode Power Supply) application. Reference circuits generate constant voltage(5V) in the various of power supply and temperature condition. Error amp. is designed with large DC gain $({\simeq}65dB)$, unity frequency $({\simeq}190kHz)$ and large $PM(75^{\circ})$. comparator is designed with 2 stage. Saw tooth generators operate with 20kHz oscillation frequency. Also, we optimize drift concentration & drift length of n-LDMOSFET for design of high voltage switching device. It is shown that simulation results have the breakdown voltage of 350V. (using ISE-TCAD Simulation tool). PWM IC with power switching device is designed with 2um design rule and Bi-DMOS technology.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.3
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• pp.63-69
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• 2017

This paper presents a highly efficient power management system for UAV-drones. For free from the battery cell-balancing issue, the proposed system allows the drone to utilize a single-cell Li-Po battery. To realize low-voltage input of 3.7V, the switch-mode step-up DC-DC converter is optimally designed with high power efficiency. The prototype DC-DC converter was implemented with an output voltage of 5V, which will be provided to digital parts of the drone. The power efficiency was measured to be max. 91.3% with low surface temperature. The measured line and load regulations were 0.02V/V and 0.15V/A, respectively. Thanks to the proposed power management system, the available time-to-fly of the drone is expected to be significantly extended in virtue of the enhanced power efficiency.

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.387-392
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• 1990

In this papers, SPICE which is widely used in analysis of general circuit and simulation in electric and electrical field is applied to DC-DC converter. Be selected Forward which is widely used as SMPS(Switched Mode Power Supply) amang DC-DC converter, and showed the aveformer, we know that the converter is operated in normal. Including the control circuit in converter, by controlling the duty ratio of switch, we know that the output voltages is staple from the transient state of convwrter. Also, comparing SPICE simulation with experiment, the validity of simulate is showed.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.411-420
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• 1991

In this paper, SPICE program which is widely used in analysis of general circuit on electronic and electrical field has been applied to DC-DC converter. We have selected Forward type which is widely used us SMPS(Switched Mode Power Supply) of various electronic equipments, and have confirmed the waveforms of circuit operation, transfer of energy and resetting in transformer. And the procedure which the output voltage of converter, including the control circuit, has been stabilized from the transient state to the steady state by controlling the duty ratio of switch is presented. We have compared SPICE simulation with experiment and have verified the validity of SPICE simulation.

• Journal of IKEEE
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• v.15 no.4
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• pp.319-323
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• 2011

In this paper presents a new model of dual-mode synchronous buck converter with dynamic control for mobile applications was proposed. The proposed circuit can operate at 2.5MHz with supply voltage 2.5V to 5V for low ripple and minimum inductor and capacitor size, which is suitable for single-cell lithium-ion battery supply mobile applications. For high efficiency, the proposed circuit adopts synchronous type and dynamic control. The proposed circuit is designed by using the device parameter of TSMC 0.18um BCD process and the performance is evaluated by Cadence spectre. Experimental board level results show the maximum conversion efficiency is 96% at 100mA load current.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.4
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• pp.275-284
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• 2017

As the high-level of the industrial and information age, the electricity become the indispensable element in the daily life including OA, FA, and computer, electric home appliances, and etc. In particular, The continuous use of the high capacity power supply system by applying a Switching Mode Power Supply(SMPS) according to the increase of the secondary side output terminal of the power load of the refrigerator of the home appliance or automation of the plant is pressed. The purpose using the way with this kind of high-capacity altogether is to supply the output voltage and output current regardless of the input voltage or to the external environmental conditions of the secondary-side load fluctuation. In this paper, a combination of a Buck Converter with Boost Converter by making a constant current source to control the inductor current and maintain stable power supply side operating characteristics, when load variations. While maintaining the same characteristics as conventional Buck Converter, and offer a DC-DC Converter system with the new switch pattern having a wide output range capable of operating in Buck-Boost Converter. In addition, after theoretical analysis, we carry out simulations and experiments to verify the validity and performance comparing with a conventional DC-to-DC converter.