• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.147-150
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• 2014

In this paper, pulse current type power supply for laser diode dirver is discussed. High speed high power laser has been using widely because it becomes using on medical or manufacturing equipment, but researches have not being occurred actively. Current profiling method is proposed for improved lifetime expectancy of laser diode(LD). The current waveform of driving LD is most important factor of the performance and lifetime of LD. The proposed method improves shape and stability of current waveforms, thus will effect right direction of lifetime expectation.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.244-250
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• 2012

In this paper, The next Generation High Speed Railway Inverter system using RCF-PWM(Random Carrier Frequency Pulse Width Modulation) was developed to reduce electromagnetic noise. RCF-PWM method is randomized the switching frequency in the range between Semiconductor switching devices' maximum switching frequency and minimum switching frequency, Simulation program has been built using MATLAB/Simulink to verify the validity of study. Finally, the simulation results of Next Generation High Speed Railway inverter system using the RCF method was compared with the conventional SVPWM method.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.95-95
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• 2007

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.2
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• pp.168-172
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• 2014

A new sustain driving method is proposed to improve luminous efficiency by the generation of the self-erasing discharge during a sustain period in AC plasma display panel. As one subfield time in the conventional AC PDP is divided into the reset, address, and sustain period. Among them, as the square sustain waveform is alternately applied to the X and Y electrodes on the front plate during the sustain period, the plasma discharge for displaying the image is continuously produced. Meanwhile, in the conventional driving method, the address waveform applied to the A electrode on the rear plate is only driving during an address period and grounded during a sustain period. In this experiment, the negative pulse is applied to the A electrode at the latter part of the sustain pulse for improving the luminous efficiency producing the self-erasing discharge during the sustain period. The negative pulse on the A electrode can change from the space to the wall charge and induce the additional discharge by the accumulated wall charge when the voltages of three electrodes are grounded. As a result, the luminous efficiency will be measured with changes in the voltage level of the A electrode and the new driving method can be improved to the luminous efficiency about 32 % compared with the conventional driving method.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.23-30
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• 2009

A new high performance and low cost unified power system is proposed through investigating conventional Power-Integrated Drive(PID) system and Power-Separated Drive(PSD) system applied to LCD TV. Since the proposed system consists of two stage, namely power and inverter stage it features high efficiency and cost effectiveness. To satisfy the safety standard of the High voltage transformer, 1:1 transformer is employed between inverter and high voltage transformer. Moreover, to ensure the Zero Voltage Switching(ZVS) of all power switches and the Pulse Count Modulation(PCM) method is employed, which controls the number of pulse at the fixed frequency and fixed duty cycle. Therefore, it features high efficiency, improved heat generation, cost effectiveness and good EMI performance including no additional current balancing coil. To confirm the validity of proposed system, comparison of conventional system, verification of experimental results are presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.80-86
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• 2011

This paper presents an integrated variable amplitude high voltage pulse generation circuit with low power and small size for driving industrial piezoelectric printer heads. To solve the problems of large size and power overhead of conventional pulse generators that usually assembled with multiple high-cost discrete ICs on a PCB board, we have designed a new integrated circuit (IC) chip. Since all the functions are integrated on to a single-chip it can achieve low cost and control the high-voltage output pulse with variable amplitudes as well. It can also digitally control the rising and falling times of an output high voltage pulse by using programmable RC time control of the output buffer. The proposed circuit has been designed and simulatedd in a 180[nm] Bipolar-CMOS-DMOS (BCD) technology using HSPICE and Cadence Virtuoso Tools. The proposed single-chip pulse generation circuit is suitable for use in industrial printer heads requiring a variable high voltage driving capability.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.26-29
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• 2008

In the fields of electronics and displays where inkjet printing has demonstrated its capability to fabricate colorant subpixels of thin film transistor liquid crystal(TFT LCD) color filters and organic light emitting diode (OLED) displays, conducting tracks and TFTs, the production of satellite droplets is one of primary things to eliminate because they generally deteriorate the pattern quality. To understand the production mechanism of satellite droplets in this paper, driving waveforms such as monopolar and bipolar were employed and the influence of the pulse duration time were investigated in both experimental and numerical aspects.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.195-198
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• 2000

In this paper the insulation characteristics test results of 25 low-voltage induction motors($3\phi$, 5HP, 380V) are presented. Five different types of insulation techniques are applied to 25 motors. The maximum partial discharge (PD) magnitude ($\textrm{Q}_{m}$) discharge inception voltage (DIV) dissipation factor tip-up ($\Delta$tan$\delta$) and rate of change in AC current($\Delta$I) are measured by PD and AC current tests. Also the insulation breakdown tests by high voltage pulse are performed and the corresponding breakdown voltage are obtained.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.228-230
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• 2004

This paper describes a new method of detecting rotor position in switched reluctance motor(SRM). Some strategies of position sensorless control methods for the motor include the measurement of phase current and applied pulse voltage in an unexcited phase. The principle of the estimation of a rotor position is based on the detection of inductance by pulse currents. Suggested method is verified by some experimental tests.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.205-210
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• 2006

어드레스-표시 동시 구동방식에 의한 고속 구동기술을 개발하기 위하여 PDP의 어드레스 기간에 인가하는 주사 펄스의 폭에 의한 방전특성을 실험용 PDP를 사용하여 실험하였다. 본 연구에서는 주사 펄스의 폭과 주사 펄스와 이어서 인가되는 첫 번째 서스테인 펄스 사이의 시간간격을 변화시키면서 어드레스 방전특성을 측정하였다. 실험결과 주사펄스의 폭이 $1.3{\mu}s$ 이하로 좁아지면 어드레스 방전의 벽전하 대신에 공간전하로 서스테인 방전이 유도되므로 각 전극에 인가하는 펄스의 전압조건이 달라져야 한다는 것을 알았다 또한 주사 펄스폭이 좁아지면 어드레스 방전개시전압이 크게 상승함을 알았다. 실험결과 12개의 서브필드를 가지며 1080개의 주사선을 가지는 full-HDTV급 PDP를 구동시킬 수 있는 조건인 $0.7{\mu}s$ 수준의 주사 펄스폭 이상에서 약 10V의 일정한 서스테인 구동마진이 얻어짐을 알았다.