• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2006.11a
• /
• pp.53-81
• /
• 2006

A COG(Chip on Glass) bonding process that is one of display packaging technology and bonds between driver IC chip and a glass panel using ACF(Anisotropic Conductive Film)has been investigated by using diode laser. This method is possible to raise cure temperature of ACF within one second and can reduce the total process time for COG bonding by a conventional method such as a hot plate. Also we can get good pressure mark on the surface of electrodes and higher bonding strength than that by convention method. Results show that laser COG bonding can give low pressure bonding and decrease a warpage of panel. We believe that it can be applied to fine pitch module.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2537-2540
• /
• 2001

The purpose of this study is to examine the calculated method of loss characteristics of full-bridge eletronic ballast for 250Watt HID lamps by approximated modeling. These lamps have the most emit effiency and color rendering. Especially, the majority of losses appear to the MOSFET do full-bridge, L of output terminal and driver IC, besides losses occur to the R in the ballast. These losses cause heating and breakage of MOSFET. When HID-lamp arrivals the steady-state, loss of ballast is measured 9% and analyzed value is 8% approximately. Accordingly it is not too much to say that greater part of losses is examined.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.359-361
• /
• 2007

본 논문은 CNT(Carbon Nano Tube) FEL(Field Emission Lamp)에서 애노드(Anode)-캐소드(Cathode) 구동용 고전압 구동 회로 구현에 관한 것이다. 본 논문에서 제안하는 고전압 DC 전원 회로는 턴비가 높은 고전압 트랜스포머의 Leakage 인덕턴스를 이용하는 Series-Resonant 형태의 Full Bridge 컨버터를 적용하고 고전압 트랜스포머와 Voltage Multiplier를 이용한다. 고전압 트랜스의 절연전압을 줄이기 위해서 두개의 트랜스포머와 Voltage Multiplier를 이용하여 애노드 전극에는 Positive 고전압, 캐소드 전극에는 Negative 고전압을 인가한다. 이 경우 애노드와 캐소드 사이의 아크 방전 시에도 구동 IC 및 스위칭 소자를 보호할 수 있는 장점이 있다.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.144-146
• /
• 2007

본 논문에서는 고효율 LCD Backlight 구동을 위해 주로 사용하던 Phase shift Full bridge 방식을 대신할 수 있는 Dual Half Bridge Inverter를 제안하였다. 제안된 회로는 일반적인 Push-Pull 인버터 구동용 제어 IC의 출력 신호 2개로 스위치 4개를 제어할 수 있으며 넓은 범위의 ZVS(zero voltage switching)을 보장하여 소자 발열 및 효율 상승의 이점을 가진다. 제안된 Inverter Topology를 소개하며 동작모드 해석과 시뮬레이션 및 실험을 통한 검증결과를 제시 한다.

• Proceedings of the KIPE Conference
• /
• 2017.07a
• /
• pp.577-595
• /
• 2017

${\bullet}$ Silicon Carbide (SiC) had excellent material properties as the base material for next generation of power semiconductor. In developing SiC MOSFET, gate oxide reliability issues had to be first overcome before commercial application. Besides, a high and stable gate-source voltage threshold $V_{GS(th)}$ is also an important parameter for operation robustness. SiC MOSFET with such characteristics can directly use existing high-speed IGBT gate driver IC's. ${\bullet}$ The linear voltage drop characteristics of SiC MOSFET will bring lower conduction loss averaged over full AC cycle compared to similarly rate IGBT. Lower switching loss enable higher switching frequency. Using package with auxiliary source terminal for gate driving will further reduce switching losses. Dynamic characteristics can fully controlled by simple gate resistors. ${\bullet}$ The low switching losses characteristics of SiC MOSFET can substantially reduce power losses in high switching frequency operation. Significant power loss reduction is also possible even at low switching frequency and low switching speed. in T-type 3-level topology, SiC MOSFET solution enable three times higher switching freqeuncy at same efficiency.

• Smart Media Journal
• /
• v.8 no.3
• /
• pp.47-52
• /
• 2019

In this paper, we designed HW / SW interfaces for processing the signals of capacitive sensors like Electric Potential Sensor (EPS) to detect the surrounding electric field disturbance as feature signals in motion recognition systems. We implemented a smart light control system with those interfaces. In the system, the on/off switch and brightness adjustment are controlled by hand gestures using the designed and fabricated interface circuits. PWM (Pulse Width Modulation) signals of the controller with a driver IC are used to drive the LED and to control the brightness and on/off operation. Using the hand-gesture signals obtained through EPS sensors and the interface HW/SW, we can not only construct a gesture instructing system but also accomplish the faster recognition speed by developing dedicated interface hardware including control circuitry. Finally, using the proposed hand-gesture recognition and signal processing methods, the light control module was also designed and implemented. The experimental result shows that the smart light control system can control the LED module properly by accurate motion detection and gesture classification.

• Journal of Korean Society of Transportation
• /
• v.27 no.2
• /
• pp.95-105
• /
• 2009

Traffic accidents on highways are likely to happen when there is an imbalance in the complex relationships among key elements such as road geometries, driver related factors, and mechanical performances. The Demand-Effort Model (DEM), which evaluates highway safety, can be explained by the imbalance, which occurs when the level of demand of the driver's attention to the road environment exceeds that of the response from the driver. This study suggests a new model that improves the reliability of the current DEM through the reinterpretation on the physiological signals with the help of the Neural Network Model (NNM). The data were collected from 149 subjects, who drove a test vehicle on the Yongdong, Honam, and Seohaean Expressways in Korea. Three important results could be drawn from the recursive tests as follows; (1) Only 5 out of 10 parameters on the physiological signals which are currently used were proven to be meaningful through the Normality Test, Cluster Analysis, and Mann-Whitney Analysis. (2) The revised DEM, which internally uses the NNM, showed more reliable results than existing DEM. Group 1, which is based on the new DEM showed 80.0% of accuracy in measuring the level of driver's efforts, however, that of Group 2 based on the current DEM was 74.3%. (3) Field tests on the Honam Expressway showed lower 'type II error' with the new DEM (40.5%) than the old DEM (58.8%). The DEM is designed as a quick and easy way to determine highway safety prior to the minute road safety audit (RSA) by a professional audit team. Then a new DEM, which is based on the NNM, needs to be considered since it showed higher reliability and lower error.

• Journal of IKEEE
• /
• v.19 no.2
• /
• pp.168-175
• /
• 2015

In this paper, we propose FPGA design technique for rotating LED display device which is capable of displaying videos with the use of the afterimage effect. The proposed technique is made up of image data correction process based on inverse gamma correction and error diffusion, block interleaving process, and data serial output process. The data correction process based on inverse gamma correction and error diffusion is an image data correction step in which image data received are corrected by inverse gamma correction process to convert the data into linear brightness characteristics, and by error diffusion process to reduce the brightness reduction phenomenon in low-gray-level which is caused by inverse gamma correction. In the block interleaving process, the data of the frames entered transversely are first saved in accordance with entrance order, and then only the longitudinal image data are read. The data serial output process is applied to convert the parallel data in a rotating location into serial data and send them to LED Driver IC, in order to send data which will be displayed on high-speedy rotating LED Bar. To evaluate the accuracy of the proposed FPGA design technique, this paper used XC6SLX45-FG484, a Spartan 6 family of Xilinx, as FPGA, and ISE 14.5 as a design tool. According to the evaluation analysis, it was found that goal values were consistent with simulation values in terms of accurate operation of inverse gamma and error diffusion correction, block interleaving operation, and serialized operation of image data.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.1
• /
• pp.59-67
• /
• 2007

This paper presents a low power dual-level low voltage differential signaling (DLVDS) technique using current source switching for LCD driver ICs in portable products. The transmitter makes dual level signal that has two different level signal 400mVpp and 250mVpp while keeping the advantages of LVDS. The decoding circuit recovers the primary signal from DLVDS. The low power DLVDS is implemented using a $0.25{\mu}m$ CMOS process under 2.5V supply. The proposed circuit shows 800Mbps/2-line data rate and 9mW, 11.5mW power consumptions in transmitter and receiver, respectively. The proposed DLVDS scheme reduce power consumption dramatically compare with conventional one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.05a
• /
• pp.713-716
• /
• 2008

This paper presents an automatic back-light brightness control system for mobile displays. One of the most important factors in mobile display is the power consumption due to the limited and movable power source. More than 80% of power of the LCD display is consumed by LED bark-light unit (BLU). The target brightness also becomes higher because of its moving picture and high resolution image, so there are some side effects for not only excessive power consumption but also ergonomic inconvenience in dark environment. To prevent this discomfort and reduce power consumption, this paper proposes automatic brightness control (ABC) technique in mobile displays. Developed system contains TFT-LCD panel with built-in photo sensor, driver IC capable of controlling photo sensor, and BLU. Since the photo sensor array built in panel detects automatically outdoor ambient light intensity, the power of BLU in dark environment is reduced. Developed ABC system showed reduced power consumption of 50% in dark environment. We believe that the proposed system is very useful to control power of mobile TFT-LCD.