• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.577-583
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• 2011

In AC-PDP, it is necessary to achieve high luminance efficiency, high luminance and high definition by adopting technologies such as high xenon concentration and long gap. However, it is very difficult to apply above technologies because they make many problems such as mis-discharge and high driving voltage. Especially, the reactive power of PDP must be reduced for satisfaction in international standard IEC62087. In this paper, we proposed CLHS driving method which is half sustain driver without energy recovery capacitor. In the experimental results, CLHS driving method reduced reactive power consumption about 10%. Also, CLHS driving method improved the luminance efficiency in all discharge loads. Therefor, the more the discharge load decreases, the more the luminance efficiency improves. When the discharge load is 20%, CLHS driving method improved 5.35%.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.7
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• pp.1059-1065
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• 2017

In this paper, the energy harvester with a piezoelectric materials is modeled as the electric equivalent circuit, and performances of a standard DC method and a Parallel-SSHI method are verified through experiment under variable force and load conditions. Piezoelectric generator consists of mass, damper and spring constant, and it is modeled by electrical equivalent circuit with RLC components. Standard DC and Parallel-SSHI are used as power conversion methods, and standard DC consists of full-bridge rectifier and smoothing capacitor. Parallel-SSHI method is composed of L-C resonant circuit, zero-crossing detector and full-bridge rectifier. In case of simulation under $100k{\Omega}$ load condition, the harvested power is $500{\mu}W$ in Standard DC and $670{\mu}W$ in Parallel-SSHI, respectively. In experiment, the harvested power under $100k{\Omega}$ load condition is $420{\mu}W$ in standard DC and $602{\mu}W$ in Parallel-SSHI. Harvested power of Parallel-SSHI is improved by approximately 40% more than that of standard DC method.

• Journal of Electrical Engineering and Technology
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• v.6 no.5
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• pp.677-683
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• 2011

The present paper describes the setup of standard partial discharge calibrator for measuring partial discharge and estimating uncertainties. The standard PD calibrator was designed and set up, consisting of a digital pulse generator, capacitor modules, and a digital oscilloscope controlled by software developed in the laboratory. Using this software, averages of charges and rising times and their standard deviations in the measured pulses can also be calculated. The standard PD calibrator generates five types of pulses: single, double, random, oscillating, and long-rising. The coefficient sensitivities to estimate the uncertainties of pulses were extracted in the model circuit of the standard PD calibrator. The uncertainties of charges and rising times in pulses of the standard PD calibrator were estimated with single pulses. These values were 0.3%-1.4% in charges and 1.9%-7.0% in rising time; however, these values are lower than the limit values in IEC 60270.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.605-610
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• 2010

The devices based on electrically erasable programmable read-only memory (EEPROM) structure are proposed for the detection of external electric charges. A large size charge contact window (CCW) extended from the floating gate is employed to immobilize external charges, and a control gate with stacked metal-insulator-metal (MIM) capacitor is adapted for a standard single polysilicon CMOS process. When positive voltage is applied to the capacitor of CCW of an n-channel EEPROM, the drain current increases due to the negative shift of its threshold voltage. Also when a pre-charged external capacitor is directly connected to the floating gate metal of CCW, the positive charges of the external capacitor make the drain current increase for n-channel, whereas the negative charges cause it to decrease. For an p-channel, however, the opposite behaviors are observed by the external voltage and charges. With the attachment of external charges to the CCW of EEPROM inverter, the characteristic inverter voltage behavior shifts from the reference curve dependent on external charge polarity. Therefore, we have demonstrated that the EEPROM inverter is capable of detecting external immobilized charges on the floating gate. and these devices are applicable to sensing the pH's or biomolecular reactions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.197-204
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• 2010

This paper proposes a new body-effect compensated switch configuration for low voltage and low distortion switched-capacitor (SC) applications. The proposed circuit allows rail-to-rail switching operation for low voltage SC circuits and has better total harmonic distortion than the conventional bootstrapped circuit by 19 dB. A 2-1 cascaded sigma-delta modulator is provided for performing the high-resolution analog-to-digital conversion on audio codec in a communication transceiver. An experimental prototype for a single-stage folded-cascode operational amplifier (opamp) and a 2-1 cascaded sigma-delta modulator has been implemented m a 0.25 micron double-poly, triple-metal standard CMOS process with 2.7 V of supply voltage. The 1% settling time of the opamp is measured to be 560 ns with load capacitance of 16 pF. The experimental testing of the sigma-delta modulator with bit-stream inspection and analog spectrum analyzing plot is performed. The die size is $1.9{\times}1.5\;mm$.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.879-891
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• 2009

Impedance of rails is increased by the magnetic coupling between rails and reinforcing bars in the concrete slab track. Currently, the current of track circuit has been compensated by installing the compensation capacitors on track circuit because of increasing the impedance of rails. In case of a rapid transit railway, the compensation capacitors are installed every 20[m] to compensate the current of track circuit in the concrete slab track. Because the interval of one block for a rapid transit railway is as long as 1500[m], the compensation capacitors are installed about the number of 70$\sim$75 on track circuit. However, in case the compensation capacitors are broken over the number of three, it is a problem that the amplitude of current is under standard amplitude of current which is 0.8[A]. In this paper, it was suggested installing a compensation capacitor by using resonance phenomenon on the concrete slab track. We represent the electrical model of track circuit and the four terminal network, calculate the parameters demanded for the electrical model in the concrete slab track. Also, we computed the position and capacitance of the compensation capacitor about 2040[Hz], 2400[Hz], 2760[Hz], 3120[Hz] which currently is the track circuit frequency in the Gyeongbu rapid transit railway and demonstrated the validity of it, using the Matlab and PSpice program.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1214-1217
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• 2004

현재 전기용량의 국가표준은 1 kHz, 1592 Hz에서만 유지 및 보급이 되고 있다. 그러나 전기용량 및 임피던스를 측정하는 브리지와 LCR meter들은 비교적 넓은 주파수 범위에서 측정이 가능하도록 생산이 되고 있다. 따라서 이러한 기기들의 교정은 실제적으로 사용되고 있는 주파수 전 영역이 아닌 1 kHz 만 되고 있어서 완전한 교정이라고 할 수 없다. 본 논문에서는 이를 해결하기위하여 임피던스 analyzer의 one-port 측정기술을 사용하여 4-terminal-pair(이하 4TP) 전기용량 표준기 각각의 terminal에서 임피던스를 필요 주파수에서 측정하고, 측정된 임피던스 matrix를 이용하여 4TP의 transfer 어드미턴스와 출력임피던스를 계산 하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.85-90
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• 2013

In this paper, 6bit SAR ADC tolerant to ionizing radiation is presented. Radiation tolerance is achieved by using the Dummy Gate Assisted (DGA) MOSFET which was proposed to suppress the leakage current induced by ionizing radiation and its comparing sample is designed with the conventional MOSFET. The designed ADC consists of binary capacitor DAC, dynamic latch comparator, and digital logic and was fabricated using a standard 0.35um CMOS process. Irradiation was performed by Co-60 gamma ray. After the irradiation, ADC designed with the conventional MOSFET did not operate properly. On the contrary, ADC designed with the DGA MOSFET showed a little parametric degradation of which DNL was increased from 0.7LSB to 2.0LSB and INL was increased from 1.8LSB to 3.2LSB. In spite of its parametric degradation, analog to digital conversion in the ADC with DGA MOSFET was found to be possible.

• Fire Science and Engineering
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• v.29 no.6
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• pp.91-97
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• 2015

Skyscrapers, large business buildings, and IT consumers use many appliances, and the electrical power stems can cause fires by overheating. This can result in damaged capacitors, lost data, rising ground potential, and communication obstacles from linear or nonlinear high frequency. To make sure of that we investigated 7 spots of a building, among which 6-spots were fair but the other one needed high frequency control. Spots 3, 6, and 7 needed diagnostic workup, and spots 2, 3, and 5 considered 5 high frequency currents. A phase is all of good but the high frequency current is greater than the standard level except for spot 1. As a result, a zigzag transformer or active filter needs to be installed, and the efficiency needs to be upgraded by investigating load unbalance factors and power factors.

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.1
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• pp.27-39
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• 1967

The fabrication of the barium titanate ceramic capcitors has been studied. The effects of the impurities for alumina and silica upon mechanical and electrical characteristics have been examined in detail. The preparation of equimolar titanium oxide and barium carbide in addition two percent of alumina and point two five perdcent of silica has shown the best results. This is fired up to thirteen hundred degrees Celsius with the rate of two hundred degrees Celsius per hour and soaked three hous at this temperature. The dielectric constant of this sample is approximately equal with the standard and theoretical values at room temperature. The insulation resitances of the most fabricated capacitors are in the order of twenty thousand megohms, the dielectric constant and the dissipation factor are almost flat up to just below of curie temperature, and the porosities of the most ceramics are less than point one percent and well close or equal to zero percent.