• Proceedings of the IEEK Conference
• /
• 대한전자공학회 1999년도 추계종합학술대회 논문집
• /
• pp.340-343
• /
• 1999

In this paper, we propose a wide range PLL(Phase Locked Loop) for 64X CD-ROMs & l0X DVD-ROMs. The frequency locking range of the Proposed PLL is 75MHz~370MHz. To reduce jitters caused by large VCO gain and supply voltage noise, a new V-I converter and a differential delay cell are used in 3-stage ring VCO, respectively. The new V-I converter has a 0.6V ~ 2.5V wide input range. In addition, we propose a new charge pump which has perfect current matching characteristics for the sourcing/sinking current. This new charge pump improves the locking time and the locking range of the PLL. This Chip is implemented in 0.25${\mu}{\textrm}{m}$ CMOS process. It consumes 55㎽ in worst case with a single 2.5V power supply.

• Transactions on Electrical and Electronic Materials
• /
• 제14권3호
• /
• pp.160-163
• /
• 2013

We investigated the effect of light intensity and wavelength of a solar cell device by using photoconductive atomic force microscopy (PC-AFM). The $POCl_3$ diffusion doping process was used to produce a p-n junction solar cell device based on a Poly-Si wafer and the electrical properties of prepared solar cells were measured using a solar cell simulator system. The measured open circuit voltage ($V_{oc}$) is 0.59 V and the short circuit current ($I_{sc}$) is 48.5 mA. Also, the values of the fill factors and efficiencies of the devices are 0.7% and approximately 13.6%, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, was used for direct measurements of photoelectric characteristics in local instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics were observed. Results obtained through PC-AFM were compared with the electric/optical characteristics data obtained through a solar simulator. The voltage ($V_{PC-AFM}$) at which the current was 0 A in the I-V characteristic curves increased sharply up to 1.8 $mW/cm^2$, peaking and slowly falling as light intensity increased. Here, $V_{PC-AFM}$ at 1.8 $mW/cm^2$ was 0.29 V, which corresponds to 59% of the average $V_{oc}$ value, as measured with the solar simulator. Also, while light wavelength was increased from 300 nm to 1,100 nm, the external quantum efficiency (EQE) and results from PC-AFM showed similar trends at the macro scale, but returned different results in several sections, indicating the need for detailed analysis and improvement in the future.

• Korean Journal of Materials Research
• /
• 제28권11호
• /
• pp.680-684
• /
• 2018

We investigate the effect of light intensity and wavelength of a solar cell device using photoconductive atomic force microscopy(PC-AFM). A $POCl_3$ diffusion doping process is used to produce a p-n junction solar cell device based on a polySi wafer, and the electrical properties of prepared solar cells are measured using a solar cell simulator system. The measured open circuit voltage($V_{oc}$) is 0.59 V and the short circuit current($I_{sc}$) is 48.5 mA. Moreover, the values of the fill factors and efficiencies of the devices are 0.7 and approximately 13.6 %, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, is used for direct measurements of photoelectric characteristics in limited areas instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics are observed. Results obtained through PC-AFM are compared with the electric/optical characteristics data obtained through a solar simulator. The voltage($V_{PC-AFM}$) at which the current is 0 A in the I-V characteristic curves increases sharply up to $18W/m^2$, peaking and slowly falling as light intensity increases. Here, $V_{PC-AFM}$ at $18W/m^2$ is 0.29 V, which corresponds to 59 % of the average $V_{oc}$ value, as measured with the solar simulator. Furthermore, while the light wavelength increases from 300 nm to 1,100 nm, the external quantum efficiency(EQE) and results from PC-AFM show similar trends at the macro scale but reveal different results in several sections, indicating the need for detailed analysis and improvement in the future.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 2004년도 하계학술대회 논문집 A
• /
• pp.627-629
• /
• 2004

V type suspension string sets prevent instabilities from swing motion by the horizontal angle and by wind pressure. These installation conditions are controled mainly 3 items - normal swing angle by horizontal angle of line, unusual swing angle by strong wind, minimum vertical loads. We calculated and analysed that factors for the 765kV transmission line condition. And we were tested swing characteristics of V-string sets in real size test situation. So, we find to installation condition for the V type suspension string sets. This results will be used to design of V type suspension string set and to decision of the installation condition.

• Herbal Formula Science
• /
• 제19권1호
• /
• pp.35-49
• /
• 2011

Objectives : This study aims to reveal the characteristics of formulas in "Xi$\v{a}$o' Er Y$\`{a}$o Zh$\`{e}$ng Zh$\'{\i}$ Ju$\'{\e}$. Methods : For that objectives, We analyzes formulas in "Xi$\v{a}$o' Er Y$\`{a}$o Zh$\`{e}$ng Zh$\'{\i}$ Ju$\'{\e}$. In the text, 132 formulas were described. To comprehend the formulas, we classified them as several bases. Results : After those analyses, we bring to a conclusion as follows. 1. 30 formulas are described that treated convulsive diseases (j$\={i}$ngf$\={e}$ng, 惊風). Next, g$\={a}$n(疳), parasite infection, diarrhea/dysentery, dermatosis and etc were in the order. 2. Classified by the formulation, Yu$\'{\a}$nj$\`{i}$(圓劑) was the best(70 kinds of formulas, 53%). S$\v{a}$nj$\`{i}$(散劑) was a form of 41 formulas(31%). T$\={a}$ngj$\`{i}$(湯劑) and g$\={a}$oj$\`{i}$(膏劑) were a form of 5 formulas each. 10 formulas were assumed the form of w$\`{a}$iy$\`{o}$ngj$\`{i}$(外用劑). 3. We researched in-depth analysis of Yu$\'{\a}$nj$\`{i}$. As a results, dosage, additive(輔料) and the time to take of Yu$\'{\a}$nj$\`{i}$ were decomposed. Also, the formulas that treated convulsive diseases were analyzed by the herbs classification. Conclusions : Though the formulas that treated convulsive diseases were hard to application at local clinic, overall nosology of pediatrics was reflected comparatively. "Xi$\v{a}$o' Er Y$\`{a}$o Zh$\`{e}$ng Zh$\'{\i}$ Ju$\'{\e}$ was expected to play a role for reconsideration of formulas' formulation.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• 제37권6호
• /
• pp.24-33
• /
• 2000

Switching behaviour of the ferroelectric thin film and device characteristics of the MFSFET(Metal-Ferroelectric-Semiconductor FET) are simulated with taking into account the accumulation of oxygen vacancies near interface between the ferroelectric thin film and the bottom electrode caused by the progress of fatigue. In our switching model, relative switched charge is 0.74 nC before fatigue, but after the progress of fatigue it reduces to 0.15 nC with the generation of oxygen vacancies. It indicates that the generation of oxygen vacancies strongly suppresses polarization reversal. $C-V_G\;and\;I_D-V_G$ curves in our MFSFET device model exhibit the memory window of 2 V and show the accumulation, the depletion and the inversion regions in capacitance characteristic clearly. The difference of saturation drain current of the device before fatigue in shown by the dual threshold voltages in $I_D-V_G$ curve as 6nA/$cm^2$ and decreases as much as 50% after fatigue. Decrease of the difference of saturation drain currents by fatigue implies that the accumulation of oxygen vacancies with the fatigue should be avoided in the device application. Our simulation model is expected to play an important role in estimation of the behavior of MFSFET device with various ferroelectric thin films.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 2005년도 춘계학술대회 논문집 전기설비전문위원
• /
• pp.31-34
• /
• 2005

The 765kV transmission line will be maintained by live-line works for efficient operation, In order to maintain the 765kV transmission lines safely by live-line works, lineman have to know flashover characteristics of the insulator strings with damaged insulators. This paper suggests flashover characteristics of the 765kV insulator strings from experimental test results directly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집
• /
• pp.194-197
• /
• 2002

Applying dual layer insulator on plastic substrates improved electrical characteristics of organic thin film transistor(TFT). A high-quality silicon dioxide(SiO$_2$) suitable for a insulator was deposited on plastic substrates by e-beam evaporation at 110$^{\circ}C$. The insulator film which was treated by N$_2$ annealing at 150$^{\circ}C$ showed excellent I-V, C-V characteristics. The dual layer insulator structure of polyimide-SiO$_2$ improved the roughness of SiO$_2$ surface and showed very low leakage current. In addition, the flat band voltage has been reduced from -2.5V to about 0.5V.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제12권1호
• /
• pp.59-65
• /
• 2012

A study on the electrical characteristic analysis of solar cell diodes under experimental conditions of varying temperature and frequency has been conducted. From the current-voltage (I-V) measurements, at the room temperature, we obtained the ideality factor (n) for Space Charge Region (SCR) and Quasi-Neutral Region (QNR) of 3.02 and 1.76, respectively. Characteristics showed that the value of n (at SCR) decreases with rising temperature and n (at QNR) increases with the same conditions. These are due to not only the sharply increased SCR current flow but the activated carrier recombination in the bulk region caused by defects such as contamination, dangling bonds. In addition, from the I-V measurements implemented to confirm the junction uniformity of cells, the average current dispersion was 40.87% and 10.59% at the region of SCR and QNR, respectively. These phenomena were caused by the pyramidal textured junction structure formed to improve the light absorption on the device's front surface, and these affect to the total diode current flow. These defect and textured junction structure will be causes that solar cell diodes have non-ideal electrical characteristics compared with general p-n junction diodes. Also, through the capacitance-voltage (C-V) measurements under the frequency of 180 kHz, we confirmed that the value of built-in potential is 0.63 V.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
• /
• pp.105-108
• /
• 1989

For the purpose of fabricating of LB Ultra Thin Films. (N-docosyl pyridinium)-TCNQ(l: 1) Complex is synthesized. This specimen is verified by U.V. I.R and elemental analyzer. In fabricated LB films with this, as a measurements of electrical conduction characteristics in perpendicular direction, this films have characteristics of insulator(about $10^{-14}S/cm$). And negative resistance phenomena are observed in I-V characteristics of this films.