• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.4
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• pp.215-220
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• 2007

Leakage current of CMOS circuits has become a major factor in VLSI design these days. Although many circuit-level techniques have been developed, most of them require significant amount of designers' effort and are not aligned well with traditional VLSI design process. In this paper, we focus on technology mapping, which is one of the steps of logic synthesis when gates are selected from a particular library to implement a circuit. We take a radical approach to push the limit of technology mapping in its capability of suppressing leakage current: we use a probabilistic leakage (together with delay) as a cost function that drives the mapping; we consider pin reordering as one of options in the mapping; we increase the library size by employing gates with larger gate length; we employ a new flipflop that is specifically designed for low-leakage through selective increase of gate length. When all techniques are applied to several benchmark circuits, leakage saving of 46% on average is achieved with 45-nm predictive model, compared to the conventional technology mapping.

• ETRI Journal
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• v.44 no.3
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• pp.504-511
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• 2022

Monte Carlo simulations show that, as temperature increases, the average kinetic energy of channel electrons in a GaN transistor first decreases and then increases. According to the calculations, the relative energy change reaches 40%. This change leads to a reduced barrier height due to quantum coupling among the three-dimensional motions of channel electrons. Thus, an analysis and physical model of the gate leakage current that includes drift velocity is proposed. Numerical calculations show that the negative and positive temperature dependence of gate leakage currents decreases across the barrier as the field increases. They also demonstrate that source-drain voltage can have an effect of 1 to 2 orders of magnitude on the gate leakage current. The proposed model agrees well with the experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.5
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• pp.336-344
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• 2018

This study proposes a new PWM method for leakage current reduction and neutral point (NP) current control in three-phase three-level converter employed in bipolar DC distribution systems. The proposed PWM method uses medium vectors only when there is no need to control the NP current. Thus, common mode voltages are held constant to realize zero leakage current. Some space vectors that produce low-frequency common mode voltages are employed to minimize leakage currents when the average NP current needs to be a positive or negative value. The proposed space vector PWM is implemented based on barycentric coordinate. The validity of the proposed PWM method is verified by simulations and experiments.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1969-1971
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• 2000

This paper presents a data acquisition and analysis program modules that has been developed using the Labview program. These program modules can use to acquire and analyze leakage current data of insulator under different contamination conditions. The experimental hardware made up salt fog chamber, AC/DC power supply, transducer (shunt resistor), measurement devices and PC with the GPIB (General Purpose Interface Bus). And analysis program modules can calculate pulse level count, accumulated charge, average leakage current, power spectrum, and harmonics. The result of applying these analytical program modules to polymeric insulator is available for evaluation of leakage current characteristic of outdoor insulators.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.598-606
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• 2000

In this paper we investigated the relation between the surface degradations and anti-pollution characteristics of Room Temperature Vulcanized(RTV) silicone rubber coating that has different roughness through immersing into saline water. We utilized several analytic techniques such as atomic force microscopy(AFM) scaning electron microscopy(SEM) contact angle Salt Deposit Density(SDD) and average leakage current under the condition of salt fog. It is found that the surface roughness of treated RTV silicone rubber increased and the hydrophobicity of sample surface decreased with increasing the duration o immersion into water due to the erosion of base polymer the melting down alumina trihydrate(ATH) and the diffusion of Low Molecular weight(LMW) fluid. Despite the roughness of surface had been increased by water immersion excellant anti-pollution and recovery characteristics were maintained and SDD saturated to 0.1~0.14mg/cm$^2$. The average leakage current under salt fog increased with surface roughness. Measurement of average leakage current will be helpful to investigate surface degradation and lifetime expectation of RTV silicone coating.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.509-512
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• 1999

The main problem in porcelain as a high voltage insulator is that the water film is felled on the insulator surface due to rain, flog, and dew. In the presence of contamination. leakage current increases which may lead to flashover that could be followed by an outage of the power system. These days, high voltage polymer outdoer insulators have been studied and widely used, because they have excellent electrical and mechanical properties, superior performance of flashover for contamination. light weight, easy installation or handling. no maintenance during service, competitive price, and so on. First of a1l the excellent performance of the silicone rubber in polluted and wet conditions is attributed to the ability of the material to maintain the hydrophobicity of the surface in the presence of severe contaminants and wet conditions. This is due to a low surface energy of the silicone rubber. But the leakage current and some surface discharge occurs on the surface of insulator when the insulator is used for a long time. So the leakage current and the surface discharge current are important lo estimate the condition of the silicone rubber surface. In this paper, the average leakage current the surface discharge current the surface rubber surface with the salt fog condition for the first stage.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.2
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• pp.312-317
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• 1994

We studied the fabrication and electrical characteristics of high voltage hydrogenerated amorphous silicon thin film transistor using plasma enchanced chemical vapor deposition(PECVD). The device shows 2500${\AA}$ SiOS12T, 400-1500${\AA}$ a-Si tickness, 350V output voltage and 9.55${\times}$10S04T average on/off current ratio. We found that the leakage current of high voltage TFT occurred 0-70V drain voltage. As the leakage current depend on the a-Si thickness, the leakage current of high voltage TFT decreased by reduction of the a-Si thickness.

• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.27-32
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• 2018

Nowadays, to prevent electrical accidents in Korea, inspectors directly performed checking general electrical facilities as a cycle from every one to three years. It is difficult to presuppose an omen because intact conditions of electrical equipments are not kept at the time of inspection. In this paper, in order to ensure effectiveness of an online basis electric inspection, we developed an electrical safety IoT system using LoRa communication technology to enable monitoring mainly electrical safety components such as overcurrent, overvoltage, resistive leakage current, and power. Then we proposed a method for verifying performances of the prosed electrical safety IoT system. Resistive leakage currents are calculated by using difference of phase between voltages and currents. We verified that average errors are 0.97%, which reference goal is ${\pm}5%$ for a device, through reliability test according to conditions. Results of this research can be used as basic study materials to develop technologies for measuring three phase leakage current and for implementing public electrical safety. platform.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.886-889
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• 2001

Silicone rubber is being used for the housing material of outdoor high voltage insulators such as composite insulator, bushing, surge arrestor and cable terminator because of good tracking and erosion resistance, good hydrophobicity and recovery of hydrophobicity and chemical stability. But, the leakge current occurs on surface of the composite polymeric insulation materials when the insulator is used for a long time with severe contaminative condition and it can lead the contamination flashover. So the leakage current is important to estimate the condition of the silicone rubber surface. In this paper, aging characteristics of silicone rubber used for outdoor insulation have been hydrophobicity of silicone rubber in salt fog chamber with average leakage current monitoring for observing the transformation of surface degradation properties of silicone rubber with different ATH(alumina trihydrate, A1$_2$O$_3$$.$3H$_2$O) filler contents. The experimental results show that a higher peak leakage current and to raise a long time for tracking with increasing amount of ATH by the salt fog and heat recycle ageing.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.345-353
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• 2013

This paper discusses the experimental results in an effort to understand the tracking and erosion resistance of the micro and nano size $Al_2O_3$ filled silicone rubber (SIR) material which has been studied under the AC voltages, with ammonium chloride as a contaminant, as per IEC 60587 test procedures. The characteristic changes in the tracking resistance of the micro and nano size filled specimens were analyzed through leakage current measurement and the eroded masses were used to evaluate the relative erosion and tracking resistance of the composites. The fundamental, third and fifth harmonic of the leakage current during the tracking study were analyzed using moving average current technique. It was observed that the harmonic components of leakage current show good correlation with the tracking and erosion resistance of the material. The thermogravimetry-derivative thermo gravimetric (TG-DTG) studies were performed to understand the thermal degradation of the composites. The physical and chemical studies were carried out by using scanning electron microscope (SEM), Energy Dispersive X-ray analysis (EDAX) and Fourier Transform Infra-red (FTIR) Spectroscopy. The obtained result indicated that the performance of nano filled SIR was better than the micro filled SIR material when the % wt. of filler increased.