• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.346-349
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• 1996

In application of high power IGBT PWM inverters, the treatable power range is considerably limited due to the overvoltage caused by the stray inductance components within the power circuit. This paper proposes a new gate drive circuit for IGBTs which can actively suppress the overvoltage across the driven IGBT at turn-off and the overvoltage across the opposite IGBT at turn-on while preserving the most simple and reliable power circuit. The turn-off driving scheme has adaptive feature to the amplitude of collector current, so that the overvoltage is limited much effectively at the larger collector current. The turn-on scheme is to decrease the rising rate of the collector current by increasing input capacitance during turn-on transient when the gate-emitter voltage is greater than threshold voltage. The experimental results under various normal and fault conditions prove the effectiveness of the proposed circuit.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.4
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• pp.286-290
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• 2020

The formation of inorganic thin films in low-temperature solution processes is necessary for a wide range of commercial applications of organic electronic devices. Aluminum oxide thin films can be utilized as barrier films that prevent the deterioration of an electronic device due to moisture and oxygen in the air. In addition, they can be used as the gate insulating layers of a thin film transistor. In this study, aluminum oxide thin film were formed using two methods simultaneously, a thermal process and the DUV process, and the properties of the thin films were compared. The result of converting aluminum nitrate hydrate to aluminum oxide through a hybrid process using a thermal treatment and DUV was confirmed by XPS measurements. A film-based a-IGZO TFT was fabricated using the formed inorganic thin film as a gate insulating film to confirm its properties.

• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.76-80
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• 2019

The characteristics of a titanium oxide layer prepared using a plasma electrolytic oxidation (PEO) process were investigated, using an extended gate ion sensitive field effect transistor (EG-ISFET) to confirm the layer's capability to react with hydrogen ions. The surface morphology and element distribution of the PEO-processed titanium oxide were observed and analyzed using field-emission scanning-electron microscopy (FE-SEM) and energy-distribution spectroscopy (EDS). The titanium oxide prepared by the PEO process was utilized as a hydrogen-ion sensing membrane and an extended gate insulator. A commercially available n-channel enhancement MOS-FET (metal-oxide-semiconductor FET) played a role as a transducer. The responses of the PEO-processed titanium oxide to different pH solutions were analyzed. The output drain current was linearly related to the pH solutions in the range of pH 4 to pH 12. It was confirmed that the titanium-oxide layer prepared by the PEO process could feasibly be used as a hydrogen-ion-sensing membrane for EGFET measurements.

• Journal of Sensor Science and Technology
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• v.31 no.3
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• pp.151-155
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• 2022

In this paper, we present a highly-sensitive gate/body-tied (GBT) metal-oxide semiconductor field-effect transistor (MOSFET)-type photodetector using multi-finger structure whose photocurrent increases in proportion to the number of fingers. The drain current that flows through a MOSFET using multi-finger structure is proportional to the number of fingers. This study intends to confirm that the photocurrent of a GBT MOSFET-type photodetector that uses the proposed multi-finger structure is larger than the photocurrent per unit area of the existing GBT MOSFET-type photodetectors. Analysis and measurement of a GBT MOSFET-type photodetector that utilizes a multi-finger structure confirmed that photocurrent increases in ratio to the number of fingers. In addition, the characteristics of the photocurrent in relation to the optical power were measured. In order to determine the influence of the incident the wavelength of light, the photocurrent was recorded as the incident the wavelength of light varied over a range of 405 to 980 nm. A highly-sensitive GBT MOSFET-type photodetector with multi-finger structure was designed and fabricated by using the Taiwan semiconductor manufacturing company (TSMC) complementary metal-oxide-semiconductor (CMOS) 0.18 um 1-poly 6-metal process and its characteristics have been measured.

• Korean Journal of Remote Sensing
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• v.18 no.5
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• pp.273-280
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• 2002

This paper describes a mathematical model and its utilization algorithm for calculating the accurate target position on the ellipsoidal earth surface which corresponds to a range-azimuth coordinates of unprocessed synthetic aperture radar (SAR) images. A geometrical model which is a set of coordinate transformations is described. The side-looking directional angle (off-nadir angle) is determined in an iterative fashion by using the model and the accurate slant range which is calculated from the range sampling timing of the instrument. The algorithm can be applied not only for the geolocation of SAR images but also for the high quality SAR image generation by calculating accurate Doppler parameters.

• IEMEK Journal of Embedded Systems and Applications
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• v.6 no.5
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• pp.319-325
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• 2011

Recently, collision avoidance systems are under development to reduce the traffic accidents and driver comfort for automotive radar. Pulse radar can detect their range and velocities of moving vehicles using range gate and FFT(Fast Fourier Transform) of the doppler frequency. We designed the real time DSP(Digital Signal Processing) based automotive UWB(Ultra Wideband) radar, and implemented DSP to detect the range and velocity within 100ms for real time system of the automotive UWB radar. We also measured the range and velocity of a moving vehicle using designed automotive UWB radar in a real road environment.

• Journal of IKEEE
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• v.24 no.3
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• pp.901-908
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• 2020

This paper describes a method for scalable hardware implementation of modular inversion. The proposed scalable architecture has a one-dimensional array of processing elements (PEs) that perform arithmetic operations in 32-bit word, and its performance and hardware size can be adjusted depending on the number of PEs used. The hardware operation of the scalable processor for modular inversion was verified by implementing it on Spartan-6 FPGA device. As a result of logic synthesis with a 180-nm CMOS standard cells, the operating frequency was estimated to be in the range of 167 to 131 MHz and the gate counts were in the range of 60,000 to 91,000 gate equivalents when the number of PEs was in the range of 1 to 10. When calculating 256-bit modular inverse, the average performance was 18.7 to 118.2 Mbps, depending on the number of PEs in the range of 1 to 10. Since our scalable architecture for computing modular inversion in GF(p) has the trade-off relationship between performance and hardware complexity depending on the number of PEs used, it can be used to efficiently implement modular inversion processor optimized for performance and hardware complexity required by applications.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1644-1651
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• 1989

In this paper, a two-dimensional numerical analysis of HEMT's with gate length of 0.6um is performed. In this case, Control Volume Formulation method which has been used in the analysis of heat transfer and fluid flow is used as a numerical method. As a mobility model, empirical formula including the velocithy overshoot phenomena is used instead of two-piece mobility model. The results obtained from this numerical analysis(i.e., the region in which cahnnel is formed, the strength of electric field in the channel, the distribution of potential, and the distribution of electron concentration etc.)are in good agreement with the previous analytic results. And our results also show the parasitic MESFET's operation in the range of the high gate voltage.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.350-353
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• 2006

We enhance the stability of SaeManGeum Drainage Sluice Gate Bridge. We prevent a destruction disaster of it. We extend the life cycle of it. So We have developed the safety control system to manage the facility of bridge to the continuance. In this study, sensitive sensor and measuring instrument has been taken to consider the characteristic of the box-girder type concrete bridge. And CDMA type has adapted for wireless communication. Control program has been developed on web base. In this program, the advanced systems have applied like this; the setup of control range for management from the statistical analysis, the evaluation system for force and deformation and the control system for a heavy vehicle permit.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.56-60
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• 2006

We review our studies on the growth of microcrystalline silicon films by the standard PECVD technique. In situ spectroscopic ellipsometry studies allow the optimization of the complex film structure with respect to competing aspects of the growth process. Fine tuning the hydrogen flux, the ion energy, and the nature of the species contributing to deposition produces unique films with a fully crystallized interface with silicon nitride. These materials have been successfully incorporated in bottom gate TFTs which present mobility values in the range of 1 to 3 $cm^2/V.s$, and stable characteristics when submitted to a bias stress. The stability of these TFTs makes them suitable for driver applications in AMLCDs as well as pixel elements in OLED displays.