• Journal of the Korea Society for Simulation
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• v.4 no.2
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• pp.41-60
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• 1995

The IGBT(Insulated Gate Bipolar Transistor) is a power semiconductor device that has gained acceptance among circuit design engineers for motor drive and power converter applications. IGBT devices(International Rectifier, Proposed proposed model etc) have the best features of both power MOSFETs and power bipolar transistors, i.e., efficient voltage gate drive requirememts and high current density capability. When designing circuit and systems that utilize IGBTs or other power semiconductor devices, circuit simulations are needed to examine how the devices affect the behavior of the circuit. The interaction of the IGBT with the load circuit can be described using the device model and the state equation of the load circuit. The voltage rise rate at turn-off for inductive loads varies significantly for IGBTs with different base life times, and this rate of rise is important in determing the voltage overshoot for a given series resistor-inductor load circuit. Excessive voltage overshoot is potentially destructive, so a snubber protection circuit may be required. The protection circuit requirements are unique for the IGBT and can be examined using the model. The IGBT model in this paper is verified by comparing the results of the model with experimented results for various circuit operating conditions. The model performs well and describes experimented results accurately for the range of static and dynamic condition in which the device is intended to be operated.

• Journal of Advanced Marine Engineering and Technology
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• v.16 no.4
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• pp.102-112
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• 1992

The three-phase full(6-pulse) bridge controlled rectifier is one of the most widely used types of solid-state converters in DC drive applications for higher performance. In most of the previous designs, the gate control circuits of the converter have been designed with analog method which can be easily affected by noise. Nowdays with advances of microelectronics and power electronics, microprocessor and pheripal LSIs are increasingly used for eliminating this problems. In this paper, a novel general-purpose microprocessor -based firing system and control scheme for a three-phase controlled rectifier bridge has been developed and tested. Using the phase relations between ${\Delta}$-Y transformer in power operation part, gate pulse of the converter is generated with real time process so that microprocessor may share its time to control algorithms efficiently. The firing angle of the converter is smoothly controlled in the range of 0 $^{\dirc}$ to 180$^{\dirc}$ with a fast respone and a constant open loop gain, even for the case where the converter is fed by a weak AC system of unregulated frequency. The hardware and software control circuit implementation built around a 80286 microprocessor is discussed, and the experimental results are given. This scheme uses less hardware components and has higher dynamic performance in variable speed DC drive applications.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.2
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• pp.135-144
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• 2008

A bootstrap circuit is widely used for the floating gate power supply of Intelligent power module (IPM). A bootstrap circuit is simple and inexpensive. However, the duty cycle and on-time are limited by the requirement to refresh the charge in the bootstrap capacitor. And the value of the bootstrap capacitor should be increased as the switching frequency decreases. A charge pump circuit can be used to overcome the problems. This paper deals with an analysis and design of a charge pump circuit for the floating gate power supply of an IPM. The simulation and experiment are carried out for an induction motor drive system. The results well verifies the validity of the proposed circuit and design method.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2061-2062
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• 2006

a-Si(amorphous silicon) TFT(thin film transistor)는 TFT-LCD(liquid crystal display)의 화소 스위칭(switching) 소자로 폭넓게 이용되고 있다. 현재는 a-Si을 이용하여 gate drive IC를 기판에 집적하는 ASG(amorphous silicon gate) 기술이 연구, 적용되고 있는데 이때 가장 큰 제약은 문턱 전압(Vth)의 이동이다. 특히 고온에서는 문턱 전압의(Vth) 이동이 가속화 되고, Ioff current가 증가 하게 되고, 저온($0^{\circ}C$)에서는 전류 구동능력이 상온($25^{\circ}C$) 상태에서 같은 게이트 전압(Vg)에 대해서 50% 수준으로 감소하게 된다. 특히 ASG 회로는 여러 개의 TFT로 구성되는데, 각각의 TFT가 고온에서 Vth shift 값이 다르게 되어 설계시 예상하지 못 한 고온에서의 화면 무너짐 현상 즉 고온 노이즈 불량이 발생 할 수 있다. 고온 노이즈 불량은 고온에서의 각 TFT의 문턱전압 및 $I_D-V_G$ 특성을 측정한 결과 고온 노이즈 불량에 영향을 주는 인자가 TFT의 width와 기생 capacitor비 hold TFT width가 영향을 주는 것으로 실험 및 시뮬레이션 결과 확인이 되었다. 발생 mechanism은 ASG 회로는 AC 구동을 하기 때문에 Voff 전위에 ripple이 발생 되는데 특히 고온에서 ripple이 크게 증가 하여 출력 signal에 영향을 주어 불량이 발생하는 것을 규명하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1466-1469
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• 2008

We have fabricated 2.5 inch QQCIF AM-OLED panel driven by ZnO-TFT on a plastic substrate for the first time. The number of photo mask for the whole panel process was 5 and the TFT structure was top gate with active protection layer as a first gate insulator. Optimizing the process for the substrate buffer layer, active layer, ZnO protection layer, and gate insulator was key factor to achieve the TFT performance enough to drive OLED. The ZnO TFT has mobility of $5.4\;cm^2/V.s$, turn on voltage of -6.8 V, sub-threshold swing of 0.39 V/decade, and on/off ratio of $1.7{\times}10^9$. Although whole process temperature is below $150^{\circ}C$ to be suitable for the plastic substrate, performance of ZnO TFT was comparable to that fabricated at higher temperature on the glass.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.87-96
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• 2019

Flexible organic light-emitting diode (OLED) displays with organic thin-film transistors (OTFTs) backplanes have been studied. A gate driver is required to drive the OLED display. The gate driver is integrated into the panel to reduce the manufacturing cost of the display panel and to simplify the module structure using fabrication methods based on low-temperature, low-cost, and large-area printing processes. In this paper, pseudo complementary metal oxide semiconductor (CMOS) logic gates are implemented using OTFTs for the gate driver integrated in the flexible OLED display. The pseudo CMOS inverter and NAND gates are designed and fabricated on a flexible plastic substrate using inkjet-printed OTFTs and the same process as the display. Moreover, the operation of the logic gates is confirmed by measurement. The measurement results show that the pseudo CMOS inverter can operate at input signal frequencies up to 1 kHz, indicating the possibility of the gate driver being integrated in the flexible OLED display.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.939-942
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• 2002

본문의 내용은 영구자석을 사용한 단상 브러시리스 모타의 구동을 위한 H-Brdige 구동회로에 적용된 전류제어 회로에 관한 실험결과이다. 부하전류가 목표치 이상인 경우 enable 를 차단하면 순간적으로 센서저항의 전위가 0 으로 되고 이로인해 다시 순간적으로 스위칭이 이루어 지므로 매우 빠른 주기로 스위칭을 반복한다. 이 문제점을 해결하기 위하여 래칭회로를 필요로 하는데, 본 제안에서는 두 개의 NAND GATE 와 하나의 NOT GATE, 그리고 RC network 를 조합하여 LIP-FLOP 과 시지연을 이루는 방법을 실현하였다. 이와 같은 전류제어회로는 constant off time 의 특성을 가지는데, 일반적으로 사용되는 PWM 제어회로에 비하여 매우 단순하면서도, 저항부하 및 모타부하에 대해 공히 능동적으로 작동함을 입증하고 있다. 본문에서는 제안된 전류제한회로의 구조와 H-bridge 구동모드, 그리고 전기적 특성에 대한 연구결과를 설명한다.

• ETRI Journal
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• v.38 no.4
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• pp.645-653
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• 2016

This paper demonstrates the performance of a metal-substrate power module with multiple fabricated chips for a high current electrical application, and evaluates the proposed module using a 1.5-kW sinusoidal brushless direct current (BLDC) motor. Specifically, the power module has a hybrid structure employing a single-layer heat-sink extensible metal board (Al board). A fabricated motor driver IC and trench gate DMOSFET (TDMOSFET) are implemented on the Al board, and the proper heat-sink size was designed under the operating conditions. The fabricated motor driver IC mainly operates as a speed controller under various load conditions, and as a multi-phase gate driver using an N-ch silicon MOSFET high-side drive scheme. A fabricated power TDMOSFET is also included in the fabricated power module for three-phase inverter operation. Using this proposed module, a BLDC motor is operated and evaluated under various pulse load tests, and our module is compared with a commercial MOSFET module in terms of the system efficiency and input current.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.815-818
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• 1998

The Insulated Gate Bipolar Transistor has the characteristics of MOSFET and BJT. The characteristics of proposed device exhibit high speed switching, the voltage controlled property, and the low ON resistance. This hybrid device has been used and developed continuously in the power electronic engineering field. We can simulate many IGBT circuits, such as the motor drive circuit, the switching circuits etc, with PSpice. However, some problems in PSpice is that the IGBT is old-fashioned and is very difficult to get it. In this paper, the IGBT in PSpice is considered as the basic structure. We changed the valuse of base width, gate-drain overlaping area, device area, and doping concentration, then calculated MOS transconductance, ambipolar recombination lifetime etc. Using this resultant parameter, we could predict the transient response characteristicsof IGBT, for examplex, voltage overshoot, the rising curve of voltage, and the falling curve of current.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1580-1581
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• 2011

The linear accelerator of Pohang Accelerator Laboratory(PAL) will drive a top-up mode operation in PLS-II(Pohang Light Source-II). Due to this kind of the operation mode, the electron gun is expected to have shorter life time of the cathode. Further in the PLS-II, two gate valves will be installed in front of the electron gun. The distance between the pre-bunching section and the electron gun will increase by 400 mm compared to the existing system due to the insertion of these gate valves. As a result the incident electron beam. One of the goals to improve the beam pulse width is by incorporating suitable biased voltage. In this paper, we will present test results of beam pulse width as a function of different biased voltage and focusing solenoid coil.