• Title/Summary/Keyword: High leakage current

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Gate Leakage Current of Power GaAs MESFET's at High Temperature

  • Won Chang-sub;Ahn Hyungkeun;Han Deuk-Young
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.44-46
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    • 2001
  • Increase of gate leakage current causes decrease of gain and increase of noise. In this paper, gate leakage current of GaAs MESEFTs' has been traced with different temperatures from $27^{\circ}C\;to\;350^{\circ}C$ to obtain the zero voltage saturation current $J_s$ which is critical to the temperature dependency of total current. From the results, thermal leakage current coefficient has been proposed to compensate for the total current due to the thermionic emission, tunneling, generation and/or hole injection.

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Development of Electric Instrument of Current and Leakage Current based on NI-9223 and Current Prove (NI-9223과 전류프로브를 이용한 전류 및 누설전류 측정장치 개발)

  • Kim, Sung-Chul;Kim, Un-Sul
    • Journal of the Korean Society of Safety
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    • v.27 no.6
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    • pp.48-53
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    • 2012
  • This paper is purposed to develop portable electric instrument to select NI-9223(National instrument comp.) and clamp meter(HIOKI comp.), which can be used in developing electric instrument, to detect leakage current(ZCT) and current(CT) signals. In this paper, The electric instrument that can interface with current and leakage current instrument(HIOKI 9283), is developed by NI-9223 of NI comp.. HIOKI clamp meter can measure current signals certainly by high-sensitivity of 10 ${\mu}A$ resolution(leakage current : at 10 mA range) and current 1~200A range. The NI-9223 use four 16-bit analog-to-digital converters(ADCs) for true simultaneous sampling at up to 1 MS/s per channel. NI-9223 can synchronize all analog input modules installed in the same chassis to share the same start clock and/or sample clocks. The monitoring program is developed by SignalExpress of LabVIEW. The monitoring program are developed to analyze at simultaneous sampling on electrical signals such as leakage current(ZCT) and current(CT). The developed system verification tests were conducted, and portable electric instrument can be used in place which requires analysis of the actual electrical signal.

The Effect of Transformer Leakage Inductance on the Steady State Performance of Push-pull based Converter with Continuous Current

  • Chen, Qian;Zheng, Trillion Q.;Li, Yan;Shao, Tiancong
    • Journal of Power Electronics
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    • v.13 no.3
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    • pp.349-361
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    • 2013
  • As a result of the advantages such as high efficiency, continuous current and high stability margin, push-pull converter with continuous current (PPCWCC) is competitive for battery discharge regulator (BDR) which plays an important role in power conditioning unit (PCU). Leakage inductance yields current spike in low-ripple current of PPCWCCs. The operating modes are added due to leakage inductance. Therefore the steady state performance is affected, which is embodied in the spike of low-ripple current. PPCWCCs which are suitable for BDR can be separated into three types by current spike characteristics. Three representative topologies IIs1, IIcb2 and Is3 are analyzed in order to investigate the factors on the magnitude and duration of spike. Equivalent current sampling method (ECSM) which eliminates the sampling time delay and achieves excellent dynamic performance is adopted to prevent the spike disturbance on current sampling. However, ECSM reduces the sampling accuracy and telemetry accuracy due to neglecting the spike. In this paper, ECSM used in PPCWCCs is summarized. The current sampling error is analyzed in quality and quantity, which provides the foundation for offsetting and enhancing the telemetry accuracy. Finally, current sampling error rate of three topologies is compared by experiment results, which verify the theoretical analysis.

Waveform analysis of leakage current on silicon insulator for various environment condition variation (환경조건변화에 대한 실리콘애자의 누설전류 파형분석)

  • Park, Jae-Jun
    • The Journal of Information Technology
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    • v.7 no.2
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    • pp.69-76
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    • 2004
  • This paper presents the results of spectral analysis about waveforms and leakage current waveforms on contaminated silicon insulators under various environment conditions.(salt fog, clean fog, rain). The larger the leakage current during 200ms, the higher the power spectrum at 60Hz. If contaminated insulators suffers from high salt density fog, the leakage current occurs with high crest value intermittently, results in the low spectrum. Analysis of leakage current data showed that this electrical activity was characterized by transient arcing behavior contaminants are deposited on the insulator surface during salt fog tests. This provides a path for the leakage current to flow along the surface of the insulator. It is important to have an indication of the pollution accumulation in order to evaluate the test performance of a particular insulator. If the drop in surface resistivity is severe enough, then the leakage current may escalate into service interrupting flashover that degrade power quality.

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Design and Simulation Technologies of Flat Transformer with High Power Current (대전류 출력형 Flat Transformer 설계 및 해석 기술)

  • Han, Se-Won;Cho, Han-Goo;Woo, Bung-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.05c
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    • pp.15-17
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    • 2002
  • Leakage inductance and temperature rise are two of the more impotent problems facing the magnetic core technology of today's high frequency transformers. Excessive leakage inductance increases the stress on the switching transistors and limits the duty-cycle, and excessive temperature rise can lead the design limitation of high frequency transformer with high current. The flat transformer technology provides a very good solution to the problems of leakage inductance and thermal management for high frequency power. The critical magnetic components and windings are optimized and packaged within a completely assembled module. The turns ratio in a flat transformer is determined as the product of the number of elements or modules times the number of primary turns. The leakage inductance increase proportionately to the number of elements, but since it is reduced as the square of the turns, the net reduction can be very significant. The flat transformer modules use cores which have no gap. This eliminates fringing fluxes and stray flux outside of the core. The secondary windings are formed of flat metal and are bonded to the inside surface of the core. The secondary winding thus surrounds the primary winding, so nearly all of the flux is captured.

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A New Approach to On-Line Monitoring Device for ZnO Surge Arresters

  • Lee Bok-Hee;Gil Hyoung-Jun;Kang Sung-Man
    • KIEE International Transactions on Electrophysics and Applications
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    • v.5C no.3
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    • pp.131-137
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    • 2005
  • This paper describes a new approach to the algorithm and fundamental characteristics of the device for monitoring the leakage currents flowing through zinc oxide (ZnO) surge arresters. In order to obtain a technique for a new on-line monitoring device that can be used in the deterioration diagnosis of ZnO surge arresters, the new algorithm and on-line leakage current detection device for extracting the resistive and capacitive currents using the phase shift addition method were proposed. The computer-based on-line monitoring device can sense accurately the power frequency leakage currents flowing through ZnO surge arresters. The on-line leakage current monitoring device of ZnO surge arresters proposed in this work has the high sensitivity compared to the third harmonic leakage current detection devices. As a consequence, it was found that the proposed leakage current monitoring device would be useful for forecasting the defects and degradation of ZnO surge arresters.

A Dual Gate AlGaN/GaN High Electron Mobility Transistor with High Breakdown Voltages (높은 항복 전압 특성을 가지는 이중 게이트 AlGaN/GaN 고 전자 이동도 트랜지스터)

  • Ha Min-Woo;Lee Seung-Chul;Her Jin-Cherl;Seo Kwang-Seok;Han Min-Koo
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.1
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    • pp.18-22
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    • 2005
  • We have proposed and fabricated a dual gate AlGaN/GaN high electron mobility transistor (HEMT), which exhibits the low leakage current and the high breakdown voltage for the high voltage switching applications. The additional gate between the main gate and the drain is specially designed in order to decrease the electric field concentration at the drain-side of the main gate. The leakage current of the proposed HEMT is decreased considerably and the breakdown voltage increases without sacrificing any other electric characteristics such as the transconductance and the drain current. The experimental results show that the breakdown voltage and the leakage current of proposed HEMT are 362 V and 75 nA while those of the conventional HEMT are 196 V and 428 nA, respectively.

A Study on Analysis of Thyristors by the Half-sine wave Voltage (Thyristor의 반파전압에 의한 특성분석에 관한 연구)

  • Park, H.C.;Won, H.J.;Han, S.M.
    • Proceedings of the KIEE Conference
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    • 2000.07b
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    • pp.1327-1329
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    • 2000
  • The thyristor among the power-semi-conductor elements, which has large current capacity and high voltage, is used widely nowadays. When the thyristor was being used to the long time, this element may be able to arise the system trip caused by changing the characteristic and dropping the performance. Therefore, it would be necessary to analyze the characteristic of element to maintain the stable operation of the system. In oder to analyze this characteristic, it would be need to test forward direction, reverse direction and leakage current by supplying the half-sine wave voltage. Among these testing, transient current condition is generated from the testing of leakage current. This transient current may be the main factor of the error in the precise measurement of leakage current. Therefore, this paper analyzes the relationship between supply voltage and transient current in measuring leakage current of the SCR, and then suggests the condition and cause of transient current as appearing the leakage current in the testing the leakage current.

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Effects of Deposition Pressure on the Phase Formation and Electrical Properties of BiFeO3 Films Deposited by Sputtering

  • Park, Sang-Shik
    • Korean Journal of Materials Research
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    • v.19 no.11
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    • pp.601-606
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    • 2009
  • $BiFeO_3$ (BFO) thin films were prepared on $Pt/TiO_2/Si$ substrate by r.f. magnetron sputtering. The effects of deposition pressure on electrical properties were investigated using measurement of dielectric properties, leakage current and polarization. When BFO targets were prepared, Fe atoms were substituted with Mn 0.05% to increase electrical resistivity of films. (Fe+Mn)/Bi ratio of BFO thin films increases with increasing partial pressure of $O_2$ gas. The deposited films showed the only BFO phase at 10 mTorr, the coexistence of BFO and $Bi_2O_3$ phase at 30-50 mTorr, and the only $Bi_2O_3$ phase at 70 mTorr. The crystallinity of BFO films was reduced due to the higher Bi contents and the decrease of surface mobility of atoms at high temperature. The porosity and surface roughness of films increased with the increase of the deposition pressure. The films deposited at high pressure showed low dielectric constant and high leakage current. The dielectric constant of films deposited at various deposition pressures was 84${\sim}$153 at 1 kHz. The leakage current density of the films deposited at 10${\sim}$70 mTorr was about $7{\times}10.6{\sim}1.5{\times}10.2A/cm^2$ at 100 kV/cm. The leakage current was found to be closely related to the morphology and composition of the BFO films. BFO films showed poor P-E hysteresis loops due to high leakage current.

Oxidation Process of GaN Schottky Diode for High-Voltage Applications (고전압 응용분야를 위한 GaN 쇼트키 다이오드의 산화 공정)

  • Ha, Min-Woo;Han, Min-Koo;Hahn, Cheol-Koo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.12
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    • pp.2265-2269
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    • 2011
  • 1 kV high-voltage GaN Schottky diode is realized using GaN-on-Si template by oxidizing Ni-Schottky contact. The Auger electron spectroscopy (AES) analysis revealed the formation of $NiO_x$ at the top of Schottky contact. The Schottky contact was changed to from Ni/Au to Ni/Ni-Au alloy/Au/$NiO_x$ by oxidation. Ni diffusion into AlGaN improves the Schottky interface and the trap-assisted tunneling current. In addition, the reverse leakage current and the isolation-leakage current are efficiently suppressed by oxidation. The isolation-leakage current was reduced about 3 orders of magnitudes. The reverse leakage current was also decreased from 2.44 A/$cm^2$ to 8.90 mA/$cm^2$ under -100 V-biased condition. The formed group-III oxides ($AlO_x$ and $GaO_x$) during the oxidation is thought to suppress the surface leakage current by passivating surface dangling bonds, N-vacancies and process damages.