• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.7-14
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• 2008

In this paper, we designed the HVIC(High Voltage Gate Driver IC) which has improved noise immunity characteristics and high driving capability. Operating frequency and input voltage range of the designed HVIC is up to 500kHz and 650V, respectively. Noise protection and schmitt trigger circuit is included in the high-side level shifter of designed IC which has very high dv/dt noise immunity characteristic(up to 50V/ns). And also, rower dissipation of high-side level shifter with designed short-pulse generation circuit decreased more that 40% compare with conventional circuit. In addition, designed HVIC includes protection and UVLO circuit to prevent cross-conduction of power switch and sense power supply voltage of driving section, respectively. Protection and UVLO circuit can improve the stability of the designed HVIC. Spectre and Pspice circuit simulator were used to verify the operating characteristics of the designed HVIC.

• Journal of IKEEE
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• v.15 no.4
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• pp.330-338
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• 2011

In this paper, a current-mode buck-boost converter using Multiple switching devices is presented. The efficiency of the proposed converter is higher than that of conventional buck-boost converter. In order to improve the power efficiency at the high current level, the proposed converter is controlled with PWM(pulse width modulation) method. The converter has maximum output current 300mA, input voltage 3.3V, output voltage from 700mV to 12V, 1.5MHz oscillation frequency, and maximum efficiency 90%. Moreover, this paper proposes watchdog circuits in order to ensure the reliability and to improve the performance of dc-dc converters. An electrostatic discharge(ESD) protection circuit for deep submicron CMOS technology is presented. The proposed circuit has low triggering voltage using gate-substrate biasing techniques. Simulated result shows that the proposed ESD protection circuit has lower triggering voltage(4.1V) than that of conventional ggNMOS(8.2V).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.586-592
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• 2018

In this paper, HIC with various functions is proposed for the design 140W LED power control circuit. The proposed HIC integrates constant voltage/constant current circuit, short circuit protection circuit, internal constant voltage circuit, and dimmer circuit, thereby reducing the horizontal length of the PCB by 16% comparing with the conventional system. Through various experiments, we verified the performance of each block implemented inside of HIC with numerical results. (Constant voltage variation ratio: 2.9%, dimmer circuit duty variation within 5%, stable short protection at 720 mA) Since the PCB area can be significantly reduced by applying the proposed HIC. It is possible to reduce the PCB manufacturing time which takes up most of the manufacturing time, however, It is expected that the faulted power module can be replaced without replacing the whole PCB, so that maintenance / repair can be made easier.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.333-334
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• 2014

Converters employing IGCTs usually require di/dt snubber and Over Voltage Protection (OVP) circuit for the protection of IGCTs and fast diodes. In these IGCT-based converters, conventional di/dt snubber and OVP circuit dissipates a significant amount of power loss. To reduce this loss of conventional di/dt snubber and OVP circuit, this paper proposes a flyback type snubber circuit with di/dt limiting characteristic for IGCT-based converters in medium voltage wind turbines. This flyback type snubber circuit simply consists of a flyback type transformer and diode. The proposed circuit reduces loss and simplifies conventional di/dt snubber by adopting the flyback type transformer. Loss analysis of conventional di/dt snubber and OVP circuit is performed for the 3-level NPC type back-to-back VSC supplied from grid voltage of 6.9kV. The proposed flyback type snubber circuit can save the loss of conventional snubber circuit in the 3L-NPC type back-to-back VSC in multi-MW MV wind turbine. The proposed snubber circuit has a fewer number of components and improved efficiency leading to a reliable and efficient wind turbine systems.

• 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.

• Parasites, Hosts and Diseases
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• v.58 no.1
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• pp.99-102
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• 2020

Two-point mutations (V419L and L925I) on the voltage-sensitive sodium channel of bed bugs (Cimex lectularius) are known to confer pyrethroid resistance. To determine the status of pyrethroid resistance in bed bugs in Korea, resistance allele frequencies of bed bug strains collected from several US military installations in Korea and Mokpo, Jeollanamdo, from 2009-2019 were monitored using a quantitative sequencing. Most bed bugs were determined to have both of the point mutations except a few specimens, collected in 2009, 2012 and 2014, having only a single point mutation (L925I). No susceptible allele was observed in any of the bed bugs examined, suggesting that pyrethroid resistance in bed bug populations in Korea has reached a serious level. Large scale monitoring is required to increase our knowledge on the distribution and prevalence of pyrethroid resistance in bed bug populations in Korea. Based on present study, it is urgent to restrict the use of pyrethroids and to introduce effective alternative insecticides. A nation-wide monitoring program to determine the pyrethroid resistance level in bed bugs and to select alternative insecticides should be implemented.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.281-286
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• 1997

Recent construction activities and maintenance of marine facilities have been accelerating to keep up with rapid economic growth in Korea. Marine concrete structures are exposed to salts an chloride from ocean environments. The corrosion of reinforcement steel caused by chloride-penetration into concrete may severely effect the durability of concrete structures. The objective of this research is to develop a durable concrete by investigating the corrosion resistance of various corrosion protection systems utilizing different water/cement ratio, silica fumes, corrosion inhibitors and etc. A tow-year verification test on various corrosion protection systems has been doing in the laboratory and at the seaside. Corrosion investigations on reinforcement steel are now under progress for more than 180 concrete specimen. Corrosion-related measurements include macrocell corrosion current, instant-off voltage between corroding and noncorroding reinforcement, chloride contents, the corroded surface areas on the reinforcement steel, and etc. A low level of corrosion is investigated on reinforcement steels in concrete specimen made with corrosion inhibitors or applied aqueous impregnating corrosion inhibitors into their surface, even though high chloride contents of concrete specimen.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.285-288
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• 2007

This article presents the change characteristics of induced noise whether the sheath layer of the cable is grounded or not. As what affects the induced noise, there are power influence or longitudinal transverse voltages and its weighted filtered voltage. The sheath ground is basicaly predicted to have the effects of alleviation on the power influence. But practically the effects may not happen in the case of common cable's sheath layer. Rather there are cases that the ground of sheath affects so that the noise level could increase. So we need to scrutinize the effects of the sheath gorund in the measures for the protection against electromagnetic induction by powerline or traction line system. And the evaluation of using the designated shielding purpose cable is needed.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.96-103
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• 1997

This paper deals with the malfunction characteristics of the earth leakage circuit breakers(ELBs) applied by a lightning impulse voltage. In the cases of the regulation of KS C 4613 and the simulated circuits with surge protection devices, the dead operation characteristics of the ELBs against lightning impulse voltages were experimentally investigated and discussed. As a result, all the specimens(ELBs) used in this work have a cutoff performance of the lightning impulse voltage when the differential mode surges were injected at the input terminals of the ELBs owing to a surge absorber installed at the power source side of amplification circuit. Four kinds of the specimens have brought about malfunction in the condition of the lightning impulse dead operation test defined in KS C 4613, and the malfunction voltages are relatively high and are about 5-6.5[kV]. In the case of the simulated test circuit with surge protection devicesthree kinds of the ELBs have led to malfunction. Also the voltage level causing the malfunction of the ELBs is decreased by operation of surge protection devices, and it ranges from 3 to 5(kV).

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.223-230
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• 2016

This paper presents data-driven thermal protection algorithm for preventing overheating of automotive sunroof motor. When a sunroof motor operates abnormally, its coil is overheated and it is failed. Besides, drivers and passengers are damaged. Hence, the sunroof motor observes its temperature and will be stoped when its temperature reach a predefined level. In order to implement low-cost thermal protection function, we drew a knowledge-based temperature increasing and decreasing curve from the result of experimental test. And then, we implemented data-driven thermal protection algorithm which prevents motor's On/Off operation according to motor operating voltage and motor speed. Finally, we implemented experimental test bed and evaluated its feasibility.