• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.2
• /
• pp.282-289
• /
• 2008

To improve the efficiency of PDP TV, it should minimize the power losses transpired during AC-to-DC power conversion and PDP driving process. Generally the input power supply for PDP driving employes a two-stage power factor corrected converter, and it needs additional DC-to-DC converters to supply driving power for reset circuit ed sustain driver, which has high power consumption. However, such a circuit configuration has a difficulty for the PDP market requires low cost. To alleviate this problem, a new circuit composition is presented. It integrates input power supply with reset and sustain driver in a single power stack The input power supply of the proposed circuit has a single-stage structure to minimize power conversion loss, and it directly supplies power to the sustain driver so as to reduce the system size and cost.

• Journal of IKEEE
• /
• v.23 no.2
• /
• pp.517-523
• /
• 2019

Recently, researches about automobile seat having function to support the comfort to driver and passenger during the driving are conducted in various fields including automobile seat having massage function. The effect of massage depends on the pattern of massage such as time, magnitude, and shape. In this paper, linear motor actuator, which is used as driving method in the automobile massage seat, and electromagnetic analysis method, which is used to improve the magnetic efficiency in the design of autuator, is proposed. Electromagnetic analysis using finite element method is conducted in the design of linear motor actuator. Input voltage shape for massage pattern is calculated by simulation using mathematical model of actuator. Performance test for massage pattern generation is conducted with automobile massage seat having developed actuator and controller. It is verified that developed actuator system is applicable in the automobile massage seat.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.6
• /
• pp.9-13
• /
• 2019

In this study, a miniature thin film-patterned heater was fabricated on a silicon substrate using semiconductor process technology and the thermal characteristics of the applied voltage, power, and temperature of the thin film heater were measured and analyzed. The temperature of the thin film pattern heater increased with increasing power, but the temperature increase rate was gradual at high power intervals. The characteristics of the high temperature section of the platinum thin film-patterned heater were analyzed using the heat resistance model under atmospheric and vacuum conditions. The thermal resistance measured in a vacuum atmosphere was 0.79 [K/mW] higher than the heat resistance value 0.69 [K/mW] in air. The temperature of the thin film pattern heater can be maintained at a low power in a vacuum rather than in air, and these results are expected to be utilized in the structural design of a thin film-patterned heater element.

• The Journal of Korean Institute of Information Technology
• /
• v.16 no.11
• /
• pp.61-68
• /
• 2018

This paper describes design of a 10.525 GHz self oscillating mixer semiconductor IC chip combining voltage controlled oscillator and frequency mixer using silicon CMOS technology for Doppler radar applications. The p-core type VCO included in the self oscillating mixer minimizes the noise contained in the transmitted signal. This noise minimization increases the sensing distance and acts in a direction favorable to the reaching distance and the sensitivity of the motion detection sensor. Simulation results for phase noise show that a VCO designed as a P-core has a noise characteristic of -106.008 dBc / Hz at 1 MHz offset and -140.735 dBc / Hz at 25 MHz offset compared to a VCO designed with N-core and NP-core showed excellent noise characteristics. If a self-oscillating mixer is implemented using a p-core designed VCO in this study, a motion sensor with excellent range and reach sensitivity will be produced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.10a
• /
• pp.823-824
• /
• 2016

In general, distribution board, panel board and motor control center can be installed over a wide area such as residence of group, building, schools, factories, ports, airports, water service and sewerage, substation and heavy industries that are used to supply converts the voltages extra high voltage into optimal voltage. There are electrical accidents due to rise of contact temperature, loose contact of bus bar, deterioration of the contact resistance, overtemperatue of the bus bars. In this paper, we propose bus bar joints monitoring system with loose connection of bus bar, measuring the joint resistance of busbars and monitoring internal and external heat. The proposed system can be reduced the electrical accidents by maintenance of busbar joints and the temperature of the conductive contact surface of busbars.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.6
• /
• pp.129-135
• /
• 2020

This study relates to a characteristic change and frequency correction method according to the temperature sensor position of an oven-controlled crystal oscillator (OCXO) using a 10 MHz SC-CUT crystal. Although there are several methods of manufacturing the previous high-precision 10MHz OCXO, the present study shows that the frequency stability characteristics against external temperature changes can be improved simply by adjusting the position of the temperature sensor. Factors that affect the frequency characteristics of the OCXO include the temperature transmitted to the crystal, the voltage applied to the crystal, and the capacitance constituting the oscillation circuit. The amount of change in frequency due to these factors was measured, and the change in the correction value of the OCXO output frequency was investigated by measuring the temperature inflection point and changing the capacitor value.

• Journal of IKEEE
• /
• v.25 no.2
• /
• pp.381-387
• /
• 2021

As Head-Mounted Displays(HMDs), which are mainly used to maximize realism in games and videos, have experienced increased demand and expanded scope of use in education and training, there is growing interest in methods to enhance the performance of conventional HMDs. In this study, a methodology to utilize Carbon NanoTubes(CNTs) to improve the performance of gate drivers that send control signals to each pixel circuit of the HMD is discussed. This paper proposes a new circuit design method that replaces the transistors constituting the buffer part of the conventional gate driver with transistors incorporating CNTs and compare the performance of the suggested gate drive with that of a gate driver comprising only conventional transistors via simulations. According to the simulation results, by including CNTs in the gate driver, the output voltage can be increased by approximately 0.3V compared to the conventional gate driver high voltage(1.1V) at a speed of 12.5 GHz and the gate width also can be reduced by up to 20 times.

• Journal of Adhesion and Interface
• /
• v.23 no.3
• /
• pp.75-79
• /
• 2022

Graphene is a two-dimensional carbon allotrope composed of honeycomb sp² hybrid orbital bonds. It shows excellent electrical and mechanical properties and has been spotlighted as a core material for next-generation electronic devices. However, it exhibits low environmental stability due to the easy penetration or adsorption of external impurities from the formation of an unstable interface between the materials in the electronic devices. Therefore, this work aims to improve and investigate the low environmental stability of graphene-based field-effect transistors through direct growth using solid hydrocarbons as a precursor of graphene. Graphene synthesized from direct growth shows high electrical stability through reduction of change in charge mobility and Dirac voltage. Through this, a new approach to utilize graphene as a core material for next-generation electronic devices is presented.

• Journal of IKEEE
• /
• v.26 no.4
• /
• pp.659-670
• /
• 2022

An 830-Mb/s/pin transceiver for a controller supporting ×32 LPDDR2 memory is designed. The transmitter consists of eight unit circuits has an impedance in the range of 34Ω ∽ 240Ω, and its impedance is controlled by an impedance correction circuit. The transmitted DQS signal has a phase shifted by 90° compared to the DQ signals. In the receive operation, the read time calibration is performed by per-pin skew calibration and clock-domain crossing within a byte. The implemented transceiver for the LPDDR2 memory controller is designed by using a 55-nm process using a 1.2V supply voltage and has a maximum signal transmission rate of 830 Mb/s/pin. The area and power consumption of each lane are 0.664 mm² and 22.3 mW, respectively.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.4
• /
• pp.617-624
• /
• 2022

The small electric vehicles equipped with V2X(vehicle to everything) systems may provide more information and function to the existing navigation system of the vehicle. The key components of V2X technology include V2V (vehicle to vehicle), V2N(vehicle to network) and V2I (vehicle to infrastructure). This study is to design and implementation of VI type E-PTO which is interfaced with external equipments, the work designs the components of E-PTO such as DC/DC converter, DC/AC converter, battery bidirectional charging system etc. Also, it implements the devices and control systems for driving. The test results of VI type E-PTO components showed allowable 10% requirements of transient voltage variation rate and recovery time within 100ms for start/stop and normal operation.