• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.4 s.334
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• pp.53-60
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• 2005

This work Proposes and describes an LCD backlight driver IC using a voltage feedback circuit which improves the brightness uniformity. The proposed circuit controls the brightness of a backlight by amplifying of sampling voltage at a lamp. To keep the uniformity of brightness, the circuit has a reference lamp. The output voltage of the reference lamp is supplied commonly to each lamp that reduces a resistance deviation of the lamps. As a result, the proposed circuit shows brightness uniformity improvement of about $40\%$ compared to the conventional ones.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1275-1282
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• 2012

This paper proposes the 16-channel LED Driver IC for Full color LED display system. The proposed LED driver IC in this paper can draw current independent of temperature and supply voltage in each channel. Current flow in the channel is configurable via an external resistor. LED brightness is adjusted by 12-Bit PWM(Pulse Width Modulation) and 8-Bit DC(Dot Correction). A real-time monitoring of IC temperature ($130^{\circ}C/150^{\circ}C$) and LED status (open/short) is provided by LED driver IC and the user can receive warning and get information on problems. A 16-channel LED driver IC is produced using 0.35 um BCD process and the size is $2.5mm{\times}2.5mm$. In this paper, channel current characteristic and channel current control function were measured in order to verify am embodied 16-channel LED driver IC by producing a single IC test board.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.996-997
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• 2023

시각 장애인들의 시각 정보에 대한 낮은 접근성은 문화, 예술 활동에 큰 제약을 가져다 주고 있다. 실제로 시각 장애인 중 약 절반 이상이 문화, 여가생활에 만족하지 못한다고 답하였고 전시회, 미술품 감상 또는 관람 활동은 약 5%만이[1] 참여하고 있는 것으로 나타났다. 이러한 한계를 극복하기 위해 시각이라는 감각의 한계를 뛰어넘어 시각 미디어를 즐길 수 있게 하는 서비스를 제작하였고, 이는 크게 웹서비스인 web view editor와 물리적인 촉각 디스플레이로 구성된다. 시각 미디어인 이미지는 8×8로 나눠 각 영역을 OpenCV 라이브러리와 K-means clustering 알고리즘을 이용하여 9 level로 분류시키고, 구분된 level에 맞게 cell의 높낮이 차이를 두기 위하여 Arduino를 통한 회전-선형 변환기를 제작했다. Arduino의 PWM 기능을 이용해 모터의 속도와 방향을 제어하며, 각 모터의 드라이버는 Arduino와 연결되어 있어 모터의 회전을 제어하게 했다. 결과적으로 본 연구에서는 cell의 높낮이 차이를 9 level로 구분하여 시각 정보를 촉각으로 수용할 수 있는 장치를 제작하였고, 이 장치를 통해 기존의 시각 장애인들이 문화 생활을 쉽게 향유하고 이를 바탕으로 창의성과 상상력을 증대시켜 더욱 밀접하게 사회와 연결되고 소통 할 수 있는 기회의 초석이 되기를 기대하는 바이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.587-592
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• 2018

Because the brightness of an AMOLED is determined by the flowing current, each pixel of AMOLED operates via A current driving method. Therefore, it is necessary to supply power to adjust the amount of current according to THE user's requirement for AMOLED driving. In this study, an IP driver block was designed and a simulation was conducted for an AMOLED display, which supplies power as selected by users. The IP driver design focused on regulating the output power due to the OLED characteristics for the diode electric current according to the voltage to be activated by pulse-skipping mode (PSM) under low loads, and 1.5 MHz pulse-width modulation (PWM) for medium/high loads. The IP driver was designed to eliminate the ringing effects appearing from the dis-continue mode (DCM) of the step-up converter. The ringing effects destroy the power switch within the IC, or increase the EMI to the surrounding elements. The IP driver design minimized this through a ringing killer circuit. Mobile applications were considered to enable true shut-down capability by designing the standby current to fall below $1{\mu}A$ to disable it. The driver proposed in this paper can be applied effectively to the same system as the AMOLED display dual power management circuit.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.1-7
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• 2020

In recent years, as LED display systems are actively spread, study on effective control methods for an LED driver for driving the systems has been in progress. The most representative among them is the uniform brightness control method for the LED driver channel. In this paper, we propose an LED driver IC for BLU with current compensation and system protection functions to minimize channel luminance deviation. It is designed for current accuracy within ±3% between channels and a channel current of 150 mA. In order to satisfy the design specifications, the channel amplifier offset was canceled out by a chopping operation using a channel-driving PWM signal. Also, a pre-charge function was implemented to minimize the fast operation speed and luminance deviation between channels. LED error (open, short), switch TR short detection, and operating temperature protection circuits were designed to protect the IC and BLU systems. The proposed IC was fabricated using a Magnachip 0.35-um CMOS process and verified using Cadence and Synopsys' Design Tool. The fabricated LED driver IC has current accuracy within ±1.5% between channels and 150-mA channel output characteristics. The error detection circuits were verified by a test board.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.1019-1025
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• 2003

There are many kinds of seam trackers in the industrial welding field. We are proposed the contact seam tracking sensor applying strain gauges kind of contact sensor that mostly used in welding part now. For this seam tracking experiment, we made the strain gauges sensor by ourselves and tested how well the sensor tracks the seam. The experiment device consist of strain gauges sensor, amplifier circuit of strain gauges signal, saw wave generator, MOSFET power diving circuit and X-Y slide by moved DC motor. The tracking areas are X-Y planes(left, right, up and down) and the change of strain gauge resistance causes to move DC motor that connected to X-Y slide. As a result of experiment, we confirmed that the strain gauges sensor tracks a seam well, and X-Y slide DC motor was controlled by PWM control.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.7
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• pp.17-22
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• 2008

This paper presents a low-power and small-area pulse width modulator by light intensity for photoflash. Light intensity controller is achieved by using capacitor, photodiode, and comparator. The proposed circuit designs digital circuit to reduce static power consumption except comparator. And IGBT driver has short circuit protection using delay cell. The pulse width modulator has the operating range of $V_{MS}$ from 0.5V to 2.5V and pulse width of output from 0.14ms to 1.65ms at 300Hz. The pulse width modulator fabricated in $0.35-{\mu}m$ CMOS technology occupies $0.85mm{\times}0.56mm$. This circuit consumes 3.0mW at 300Hz and 3.0V.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3385-3390
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• 2015

In this paper, we constructed using a Cortex M3 microcontroller developed by ARM Inc. as a way to control the LED light more efficiently. And Using the short-range wireless communication by the Bluetooth communication method applied to control the LED light was configured to wirelessly control the wireless circuits. In this paper, users can easily download and easy to wirelessly control the LED lighting control circuit to design an Android application from Android-based smartphone so that you can control with your smartphone to have anyone to control the LED lighting control circuit wirelessly. If the LED lights radio control circuit is configured with the Cortex M3 in this paper is applicable to both indoor and outdoor and eco-friendly technology, is using LED driver to enhance the efficiency of the LED becomes stable voltage supply is made, the brightness of LED lighting control.