• Title/Summary/Keyword: current-voltage

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LDO regulator with improved regulation characteristics using gate current sensing structure (게이트 전류 감지 구조를 이용한 향상된 레귤레이션 특성의 LDO regulator)

  • Jun-Mo Jung
    • Journal of IKEEE
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    • v.27 no.3
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    • pp.308-312
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    • 2023
  • The gate current sensing structure was proposed to more effectively control the regulation of the output voltage when the LDO regulator occurs in an overshoot or undershoot situation. In a typical existing LDO regulator, the regulation voltage changes when the load current changes. However, the operation speed of the pass transistor can be further improved by supplying/discharging the gate terminal current in the pass transistor using a gate current sensing structure. The input voltage of the LDO regulator using the gate current sensing structure is 3.3 V to 4.5 V, the output voltage is 3 V, and the load current has a maximum value of 250 mA. As a result of the simulation, a voltage change value of about 12 mV was confirmed when the load current changed up to 250 mA.

High Temperature Characteristics of submicron GaAs MESFETs (고온 동작 MESFET 의 온도특성 해석)

  • 원창섭;유영한;신훈범;한득영;안형근
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.379-382
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    • 2002
  • GaAs has wide band gap, Therefore that malarial can used high Temperature application. in this paper explain to current-voltage characteristics of thermal effect. we experiment on thermal test of current-voltage characteristics and gate leakage current with real device. As a result, we propose a current-volatage characteristics model. that model base on gate leakage current, and gate leakage current influence gate source voltage.

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Characteristic Analysis of Power Compensation Condenser Considering Voltage Harmonics (전압 고조파를 고려한 역률보상용 콘덴서의 특성 분석)

  • Kim, Jong-Gyeum;Lee, Dong-Ju
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.59 no.2
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    • pp.141-145
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    • 2010
  • Most of the industrial loads includes the non-linear load as well as the linear load because there are many kinds of power conversion equipments at the input stage of the load in distribution network. The non-linear load causes the distortion of voltage waveform at PCC because the non-linear load generates the harmonic current. As a result, various voltage harmonics are existed at PCC depending on the current harmonics from the non-linear load. And, a series reactor is generally connected to the power capacitor in series to attenuate the distortion of voltage waveform and to reduce an inrush current of power capacitor. Also, harmonic current of power capacitor is highly dependent on the series reactor because it is operated with the power capacitor as a passive filter against nonlinear loads. Then, these capacitors might be damaged by the excessive voltage and current harmonic components. In this paper, we presented how to select the capacitor and series reactor to meet the requirement of the voltage distortion at PCC and analyzed the voltage, current and capacity rating of the power capacitor by the computer simulation to ensure the safe operation of power capacitor when the voltage harmonics at PCC are existed. Also, the analysis data were compared with the experimental measurements for the verification.

Surge Characteristics Analysis of Three-phase Virtual Chopping at Vacuum Circuit Breaker (진공차단기 3상 동시 차단시의 서지 특성 분석)

  • Kim, Jong-Gyeum
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.9
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    • pp.1159-1164
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    • 2018
  • Vacuum circuit breakers(VCB) are widely used for current interruption of high-voltage inductive loads such as induction motors. This VCB can be chopped off before the current zero due to its high arc-extinguishing capability. One of the outstanding features of VCB is that it can cut off high frequency re-ignition current more than other circuit breakers. If the transient recovery voltage generated in the arc extinguishing is higher than the dielectric strength of the circuit breaker, a re-ignition phenomenon occurs. The surge voltage of the re-ignition is very high in magnitude and the steepness of the waveform is so severe that it can act as a high electrical stress on the winding. If the high frequency current of one phase affects the other two phases when the re-ignition occurs, it may cause a high surge voltage due to the virtual current chopping. If the magnitude of the voltage allowed in the motor winding is high or the waveform level is too severe, it may lead to insulation breakdown. Therefore, it is necessary to reduce the voltage to within a certain range. In this study, we briefly explain the various phenomena at the time of interruption, analyzed the magnitude of the dielectric strength and the transient recovery voltage at the simultaneous three-phase interruption that can give the greatest influence to the inductive load, proposed a method to reduce the impact.

Grid Current Control Scheme at Thee-Phase Grid-Connected Inverter Under Unbalanced and Distorted Grid Voltage Conditions (계통전압 왜곡 및 불평형시 3상 계통연계인버터의 계통전류제어 기법)

  • Tran, Thanh-Vu;Chun, Tae-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.11
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    • pp.1560-1565
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    • 2013
  • This paper proposes the control method for compensating for unbalanced grid current and reducing a total harmonic distortion (THD) of the grid current at the three-phase grid-connected inverter systems under unbalancd and distorted grid voltage conditions. The THD of the grid current caused by grid voltage harmonics is derived by considering the phase delay and magnitude attenuation due to the hardware low-pass filter (LPF). The Cauchy-Schwarz inequality theory is used in order to search more easily for a minimum point of THD. Both the gain and angle of a compensation voltage at the minimum point of THD of the grid current are derived. The negative-sequence components in the three-phase unbalanced grid voltage are cancelled in order to achieve the balanced grid current. The simulation and experimental results show the validity of the proposed control methods.

Current Control for Three Phase PWM Converter Using LQ Controller with Conditional Integrator (조건부 적분기를 가지는 LQ 제어기를 이용한 3상 PWM 컨버터의 전류제어)

  • 김홍성;전윤석;조영준;목형수;최규하;김한성
    • Proceedings of the KIPE Conference
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    • 1997.07a
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    • pp.345-351
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    • 1997
  • In this paper, controller for PWM converter considering unsymetrical input voltage is designed and current controller using LQ controller with conditional integrator is proposed. And the proposed current controller is compared with other current controller-predictive controller, decoupling PI controller. As simulation results, LQ controller with Conditional Integrator shows the improved performance for DC link voltage regulation through transient test of load variation. And when unsymeritrical input voltage is applied to converter with conventional current controller considering only symetrical input voltage, input current is distorted but it is showed that current controller considering unsymetrical input has robust control characteristics under phase voltage unbalance.

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Characteristics of Latch-up Current of the Dual Gate Emitter Switched Thyristor (Dual Gate Emitter Switched Thyristor의 Latch-up 전류 특성)

  • 이응래;오정근;이형규;주병권;김남수
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.8
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    • pp.799-805
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    • 2004
  • Two dimensional MEDICI simulator is used to study the characteristics of latch-up current of Dual Gate Emitter Switched Thyristor. The simulation is done in terms of the current-voltage characteristics, latch-up current density, ON-voltage drop and electrical property with the variations of p-base impurity concentrations. Compared with the other power devices such as MOS Controlled Cascade Thyristor(MCCT), Conventional Emitter Switched Thyristor(C-EST) and Dual Channel Emitter Switched Thyristor(DC-EST), Dual Gate Emitter Switched Thyristor(DG-EST) shows to have the better electrical characteristics, which is the high latch-up current density and low forward voltage-drop. The proposed DG-EST which has a non-planer p-base structure under the floating $N^+$ emitter indicates to have the better characteristics of latch-up current and breakover voltage.

A Voltage-controlled Frequency Tunable CMOS Current-mode Filter for Software Radio (Software Radio용 전압제어 주파수가변 CMOS 전류모드 필터)

  • Bang, Jun-Ho;Ryu, In-Ho;Yu, Jae-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.871-876
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    • 2011
  • In this paper, a voltage-controlled frequency tunable current-mode integrator and a 3rd-order current-mode Chebyshev filter in 1.8V-$0.18{\mu}m$ CMOS is realized for software radio applications in system-on-chips. This filter is used for reconstruction purposes between a current-steering DAC and a current-mode mixer. Power consumption of the designed filter can be reduced by using a current-mode small size integrator. And also, cutoff frequency of this filter is variable between 1.2MHz and 10.1MHz, the power consumption is 2.85mW. And the voltage bias compensated circuit is used to control the voltage variation.in the designed filter.

Effect of Stress on Current-Voltage Characteristics of ZnO Based Ceramics

  • Jung Ju-Yong;Kim Yeong-Cheol;Seo Hwa-Il;Chung Dong-Teak;Kim Young-Jung;Min Joon-Won
    • Journal of the Semiconductor & Display Technology
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    • v.4 no.4 s.13
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    • pp.1-4
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    • 2005
  • The chemical composition and uniaxial compressive stress are varied to observe their effect on the current-voltage characteristics of ZnO based ceramics. The variation of chemical composition produces two kinds of ceramics showing ohmic and nonohmic current-voltage characteristics. The current at a fixed voltage increased with the increase of the compressive stress for both ohmic and nonohmic ceramics. Ceramics showing nonohmic behavior exhibit better reversible return of current-voltage curve when the applied compressive stress is removed from the ceramics than those showing ohmic behavior do. We found an appropriate chemical composition showing linear relation between current and stress at a fixed voltage. The ceramic materials with an appropriate chemical composition can be used as a potential sensing material in pressure sensors.

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Study on Current Conditioning Process for Improving Withstand Voltage Performance of Vacuum Interrupter (진공인터럽터의 내전압 성능 향상을 위한 전류컨디셔닝 기법 연구)

  • Cha, Young-kwang;Lee, IL-Hoi;Jeon, Ki-Beom;Jang, Ji-Hoon;Ju, Heung-Jin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.5
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    • pp.480-487
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    • 2022
  • As a process to improve the insulation performance of VIs (Vacuum Interrupters), AC voltage conditioning is generally adopted by many manufacturers. Although the insulation performance is enhanced easily with AC Voltage conditioning, it has limitations when high recovery voltage is required due to high voltage rate or capacitive current switching. In particular, impurities such as oxides segregated on the electrode surface can be removed not by the energy level of the voltage conditioning but by the higher energy level achieved by the current conditioning process In this article, the current conditioning was carried out in various conditions and its validity was examined. The current conditioning was processed by changing the amplitude of applied current, arc time, the number of tests, and frequency. The insulation performance and the status of contact surface were checked as well. We concluded that as the applied charge quantity and the conditioning coverage area increase, the conditioning effect is much higher.