• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.95-97
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• 2007

This paper studies on operating limit curve of low voltage electric machinery with respect to source voltage variation or sag. Also, it discusses electric machine and compensation equipment design methodology based on voltage quality effect assessment technology. Voltage quality standards, such as SEMI47, CBEMA, ITIC curve are regarded to examine the relation between time constants of load and sagging time of sag generator, the load(low voltage electric machinery) study. Voltage sag characteristics of loads, time constant and sag relation voltage-time operating limits are tested and verified.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.33-35
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• 2007

This paper studies on operating limit curve of low voltage electric machinery with respect to source voltage variation or sag. Also, it discusses electric machine and compensation equipment design methodology based on voltage quality effect assessment technology. Voltage quality standards, such as SEMI47, CBEMA, ITIC curve are regarded to examine the relation between time constants of load and sagging time of sag generator, the load(low voltage electric machinery) study. Voltage sag characteristics of loads, time constant and sag relation voltage-time operating limits are tested and verified.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.679-682
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• 2007

We have developed low voltage operating OLEDs with new electron transport layer. The device having a structure of ITO/2TNATA/HTL:Rubrene(1%)/HTL /new ETL/LiF/Al have been used. The voltage for achieving $1,000\;cd/m^2$ was 4.1 V, whereas the turn on voltage for the brightness of $1\;cd/m^2$ was 2.8 V. This high luminance at low operating voltage is caused by the high current density, resulting from high electron conduction property of the new electron transport layer.

• Journal of Advanced Information Technology and Convergence
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• v.8 no.2
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• pp.59-67
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• 2018

The minimum power supply voltage of a typical bandgap current reference (BGCR) is limited by operating temperature and input common mode range (ICMR) of a feedback amplifier. A new BGCR using a bandgap voltage generator (BGVG) is proposed to minimize the effect of temperature, supply voltage, and process variation. The BGVG is designed with proportional to absolute temperature (PTAT) characteristic, and a feedback amplifier is designed with weak-inversion transistors for low voltage operation. It is verified with a $0.18-{\mu}m$ CMOS process with five corners for MOS transistors and three corners for BJTs. The proposed circuit is superior to other reported current references under temperature variation from $-40^{\circ}C$ to $120^{\circ}C$ and power supply variation from 1.2 V to 1.8 V. The total power consumption is $126{\mu}W$ under the conditions that the power supply voltage is 1.2 V, the output current is $10{\mu}A$, and the operating temperature is $20^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.288-290
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• 2006

An efficiency improving method for Uninterruptible Power Supply System(UPS) was developed by using OP-AMP based application circuits such as voltage detection device, current detection device and static switch control device. The efficiency improving algorithm was made by mixing the operating concepts of On-Line type UPS with the operating concepts of Off-Line type UPS. The UPS' inverter does not work if the UPS' output load current is not higher than the low load operating current which is about 0-30(%) of the UPS' output load capacity. The low load operating current is adjustable within the half of the UPS' output load capacity. If the UPS' output load current is rising over than the low load operating current, the UPS' inverter starts working and the inverter output power feeds to the loads of UPS. If UPS' input power breaks out while UPS' inverter does not operate because the load current is low, the inverter starts working within 4(ms) with excessive output voltage which is ${\pm}$8(%) of normal UPS' output voltage. Like these. UPS can continuously feeds power to it's load device and reduce power consumptions.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.168-168
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• 2006

Low-operating voltage organic field-effect transistors (OFETs) have been realized with high dielectric constant (${\kappa}$) polymer such as cyanoethylated poly vinyl alcohol (CR-V, ${\kappa}=12$). Since the $high-{\kappa}$polymers are likely to contain water and ionic impurities, large hysteresis and considerable leakage current are frequently observed in OFETs. To solve these problems, we cross-linked the CR-V by using a cross-linking agent. Cross-linked CR-V dielectrics showed high dielectric constant of 11.1 and good insulating properties, resulting in a high capacitance ($81nF/cm^{2}$ at 1MHz) at 120 nm of dielectric thickness. Pentacene FETs with cross-linked CR-V dielectrics exhibited high carrier mobility ($0.72\;cm^{2}/Vs$), small subthreshold swing (185 mV/dec) and little hysteresis at low-operating voltage (${\Leq}-3V$).

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.170-170
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• 2006

[ ${\pi}-conjugated$ ] organic and polymeric semiconductors are receiving considerable attention because of their suitability as an active layer for electronic devices. An organic inverter with a full swing and a high gain can be obtained through the good qualities of the transfer characteristics of organic thin-film transistors (OTFTs); for example, a low leakage current, a threshold voltage ($V_{th}$) close to 0 V, and a low sub-threshold swing. One of the most critical problems with traditional organic inverters is the high operating voltage, which is often greater than 20 V. The high operating voltage may result in not only high power consumption but also device instabilities such as hysteresis and a shift of $V_{th}$ during operation. In this paper, low-voltage and little-hysteresis pentacene OTFTs and inverters in conjunction with PEALD $Al_{2}O_{3}\;and\;ZrO_{2}$ as the gate dielectrics are demonstrated and the relationships between the transfer characteristics of OTFT and the voltage transfer characteristics (VTCs) of inverter are investigated.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.6
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• pp.470-476
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• 1989

In order to develop a mathematical model which can predict the operating voltage and current of a discharge lamp, the properties and the physical phenomena of a low pressure gas discharge are investigated. Fluorescent lamp which uses a low pressure mercury-argon gas discharge is used in the model development. In a low pressure mercur-argon gas discharge, the continuity equation for each excited atom and electron, and the electron energy balance equation can predict the physical quantities of discharge. By coupling these equations and the circuit equation, the electrical characteristics of the discharge lamp can be predicted. To verify the validity of the suggested model, we calculated the voltage and current of a fluorescent lamp operating with inductor ballast for source frequency of 5KHz, 8KHz, 10KHz, and 13KHz. The results show good agreements in wave forms between the measured voltage and current, and the difference between the measured and calculated one is less than 5%.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.337-339
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• 2008

Recently, Note PCs have being widely used due to their features such as good mobility and low power consumption. In order to ensure the current market position, further improvement is required. Especially, the lower operating voltage is essential for the long operating time of Note PCs. For the achievement of lower operating voltage, possible contributions from LC materials side are to lower the viscosity and to increase the dielectric constant without sacrificing the reliability. In order to achieve lower driving voltage, new LC mixtures have been developed, optimizing theirs physical properties.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.637-640
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• 2009

The LCD based on Kerr effect is highly interesting because it uses an optically isotropic state with no need of alignment layer and it shows sub-millisecond response time. The problem of the device is that it requires very high operating voltage and the transmittance is relatively low compared with other LCDs that use nematic LC. In this work, we study on various electrode structures and driving method which can lower operating voltage.