• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.141-145
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• 2017

This paper presents a method to improve Li-ion battery charging speed for portable electronic devices maintaining stable operating temperature. The proposed method uses multiple chargers which consist of a master module and slave modules designed with single wire communication signal for parallel current path in order to simplify the additional hardware needs. A single wire communication signal control between a master module and slave modules makes the number of pins of parts lowered and the required area small, furthermore leading to lower cost. Therefore the proposed charging method can be practically used for implementing battery charging modules requiring high speed Li-ion battery charging.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.4
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• pp.73-76
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• 2010

A two-facet approach was used to investigate the parametric performance of functional high-speed DDR3 (Double Data Rate) DRAM (Dynamic Random Access Memory) die placed in different types of BGA (Ball Grid Array) packages: wire-bonded BGA (FBGA, Fine Ball Grid Array), flip-chip (FCBGA) and lead-bonded $microBGA^{(R)}$. In the first section, packaged live DDR3 die were tested using automatic test equipment using high-resolution shmoo plots. It was found that the best timing and voltage margin was obtained using the lead-bonded microBGA, followed by the wire-bonded FBGA with the FCBGA exhibiting the worst performance of the three types tested. In particular the flip-chip packaged devices exhibited reduced operating voltage margin. In the second part of this work a test system was designed and constructed to mimic the electrical environment of the data bus in a PC's CPU-Memory subsystem that used a single DIMM (Dual In Line Memory Module) socket in point-to-point and point-to-two-point configurations. The emulation system was used to examine signal integrity for system-level operation at speeds in excess of 6 Gb/pin/sec in order to assess the frequency extensibility of the signal-carrying path of the microBGA considered for future high-speed DRAM packaging. The analyzed signal path was driven from either end of the data bus by a GaAs laser driver capable of operation beyond 10 GHz. Eye diagrams were measured using a high speed sampling oscilloscope with a pulse generator providing a pseudo-random bit sequence stimulus for the laser drivers. The memory controller was emulated using a circuit implemented on a BGA interposer employing the laser driver while the active DRAM was modeled using the same type of laser driver mounted to the DIMM module. A custom silicon loading die was designed and fabricated and placed into the microBGA packages that were attached to an instrumented DIMM module. It was found that 6.6 Gb/sec/pin operation appears feasible in both point to point and point to two point configurations when the input capacitance is limited to 2pF.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.2
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• pp.137-146
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• 1998

The experimental study is concerned with two-phase closed thermosyphons, (i.e., wickless heat pipes) for the cooling of high power electronic components in telecommunication system. The thermosyphon which can deal with a high heat flux of up to $4.9W/cm^2$ is developed, and the cooling characteristics of thermosyphon is analyzed according to design parameters which are the types of and quantity of working fluid, number of pipes, wire insertion in pipe, inclination angle of thermosyphon, and cooling air velocity. Using water as working fluid is superior cooling performance compared to using acetone, and cooling performance is improved as the number of thermosyphon becomes larger, inserting wires in the pipes, and inclination of $30~60^{\circ}$.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.63-66
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• 1999

Echo and near-end crosstalk(NEXT) can be generated in two-wire duplex transmission. In this paper investigates how to cancel echoes of high speed communication. A pipeline algorithm is used to remove the echoes that high speed communication. It is least mean squared(LMS) algorithm based on the relaxed look-ahead concept, is focused on the pipelined LMS, and its performance is compared to that of the serial LMS algorithm. And we design pipelined adaptive filtering. In advanced of the hardware implementation with VHDL code the performance of pipelined LMS algorithm is verified by the computer simulation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.604-608
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• 2016

In recent years, research and development has been carried out in order to increase the economical efficiency and stability in terms of efficient use of energy for the heating apparatus. Especially, technology development for high performance and new functional materials is actively being carried out. This paper focuses on the development of exothermic products with excellent energy transfer characteristics. The heating element used for bedding or mattress uses a heating wire. Since the heating wire is thin, the distribution of heat is concentrated only around the heating wire,. In addition, electromagnetic induction is harmful to the human body and energy consumption is high. Therefore, it is aimed to develop a planar heating panel using SiC ceramics which can radiate far-infrared rays and anions to be harmless to the human body, but also has excellent heat conduction to enhance energy efficiency.

• Journal of IKEEE
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• v.26 no.4
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• pp.537-544
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• 2022

This paper analyzes the occurrence and cause of bond wires fusing used in the manufacture of pulsed high power amplifiers. Recently GaN HEMT has been spotlight in the fields of electronic warfare, radar, base station and satellite communication. In order to produce the maximum output power, which is the main performance of the high-power amplifier, optimal impedance matching is required. And the material, diameter and number of bond wires must be determined in consideration of not only the rated current but also the heat generated by the transient current. In particular, it was confirmed that compound semiconductor with a wide energy band gap such as GaN trigger fusing of the bond wire due to an increase in thermal resistance when the design efficiency is low or the heat dissipation is insufficient. This data has been simulated for exothermic conditions, and it is expected to be used as a reference for applications using GaN devices as verified through IR microscope.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.2
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• pp.31-37
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• 2015

Recently, mobile phones have become necessary tools for everyday life. In this study, a device that can serve as a separation between a touch panel and an LCD module in a mobile phone was devised for mass repair processes at a smaill business. We used a wire cutting method to separate the bonding plate area between the modules. The device is composed of DC motors and stepping motors that can deliver a precise cutting motion. The motor control system is connected by individual control modules to a CAN network. The developed device showed excellent performance at high temperature conditions.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.37-42
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• 2007

Clock grid networks are now common in most high performance microprocessors. This paper presents a new effective modeling and simulation methodology for the clock grid using scattering parameter. It also shows the effect of wire width and grid size on the clock skew of the grid. The interconnection of the clock grid is modeled by RC passive elements. The results show that the error is within 10 % comparing to Hspice simulation results.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.720-722
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• 2001

The high temperature superconductor transformer gains interests from the industries. This paper examined characteristics of the laboratory scale three phase HTS transformer and Brandt equation is used to calculate the loss by perpendicular magnetic field in transformer winding. To estimate the performance of the three phase HTS transformer no load characteristics, short circuit characteristics are calculated by using finite element method. Transient characteristics of sudden short circuit during full load operation have been examined. Effect of the resistance growth in the HTS wire from the quench of the wire is included in the calculation.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.413-415
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• 2006

Wire rods are carried by C-Hooks and are tracked by bringing the inspection sensors into contact with steel bars on the C-Hooks. However, the conventional system using mechanical equipment is not reliable due to aging, wearing and bending of steel bars. To overcome these problems, a non-contact type identification system is required. This paper introduces the radio frequency identification(RFID) technology which is one of the most popular non-contact identification methods, and evaluates its performance in the real environment of POSCO. Specifically, we use tags which are designed for operating on high temperature and allowing easy attaching and detaching on the C-Hook. A new monitoring program is developed for reacting upon the conventional system and showing the results of reading of reading tags.