• The Transactions of the Korean Institute of Power Electronics
• /
• v.6 no.6
• /
• pp.564-571
• /
• 2001

This paper presents the VLSI design of highly efficient low voltage DC/DC converter for portable devices. All active devices are integrated on a single chip using a standard 0.65$\mu\textrm{m}$ CMOS process. The converter operates at the switching frequency of 1MHz for reducing the size of passive elements and uses a ZVS for minimizing the switching loss at high frequency. Simulation results show that the circuit can achieve a 95% efficiency when the output voltage is controlled to be 2V with the load of lW.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.05a
• /
• pp.270-274
• /
• 2005

The human beings have increased concern about Energy saving and alternative energy. The power demand has increased the growth of industry and the improvement of life. We have to explore alternate energy sources and utilize effectively domestic resources. The lighting equipments developed Energy saving by using an electric ballast. The load installation should be promoted to rational power management, according to the network, inteligent, and high-function. Therefore, this paper has studied the method of energy saving and consulting.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1277-1287
• /
• 2016

This study proposes a novel isolated high step-up galvanic converter, which is suitable for renewable energy applications and integrates a boost converter, a coupled inductor, a charge pump capacitor cell, and an LC snubber. The proposed converter comprises an input inductor and thus features a continuous input current, which extends the life of the renewable energy chip. Furthermore, the proposed converter can achieve a high voltage gain without an extremely large duty cycle and turn ratio of the coupled inductor by using the charge pump capacitor cell. The leakage inductance energy can be recycled to the output capacitor of the boost converter via the LC snubber and then transferred to the output load. As a result, the voltage spike can be suppressed to a low voltage level. Finally, the basic operating principles and experimental results are provided to verify the effectiveness of the proposed converter.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.587-591
• /
• 2004

This paper proposes a novel current compensation technique that can eliminate the harmonic currents included in line currents without computation of harmonic current components. A current controller with fast dynamics for an active filter is described. Harmonic currents are directly controlled without the need for sensing and computing the harmonic current of the load current, thus simplifying the control system. Current compensation is done in the time domain, allowing a fast time response. The DC voltage control loop keeps the voltage across the DC capacitor constant. High power factor control by an active filter is described. All control functions are implemented in software using a single-chip microcontroller, thus simplifying the control circuit. Any current-controlled synchronous rectifier can be used as a shunt active filter through only the simple modification of the software and the addition of current sensors. It is shown through experimental results that the proposed controller gives good performance for the shunt active filter.

• The korean journal of orthodontics
• /
• v.21 no.1 s.33
• /
• pp.7-16
• /
• 1991

To estimate the possibility of the application of TiN ion-plating to the orthodontic appliance, colorimetric properties, and characteristics of ion-plated film as well as adhesive strength of TiN film to the substrate and mechanical properties of ion-plated orthodontic appliance were investigated. The obtained results were as follows: 1) TiN ion-plated film had the colorimetric properties which were the hue of about 2.5 Y, the brightness of about 6, and the chroma of about 4 by the standard color chip of JIS. 2) TiN ion-plated film was $2{\mu}m$ in thickness and its deposition pattern was rather irregular. 3) TiN phase was confirmed on the X-ray diffraction pattern. 4) Critical load for delamination of ion-plated film from stainless steel band was 10N. 5) Tensile and yield strength of ion-plated specimen was increased about 10Kg $f/mm^2$, while elongation was decreased $1\%$ compairing to the values of the non ion-plated specimen.

• Proceedings of the KIPE Conference
• /
• 1999.07a
• /
• pp.522-525
• /
• 1999

This paper describes a simple but effective method for energy saving of ac motors having a widely variable load. The proposed method is based on an optimal efficiency control which is operated by voltage-current pattern such as to maintain the maximum efficiency on the efficiency-output characteristics of the motor, in voltage control with triac. In this paper, authors present the experimental results of the SPIM under controlling of current of main and auxiliary winding by using a one chip microcontroller. Experiments are focused on a capacitor stating single phase induction motor the optimal energy saving are proved by the proposed method.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.16 no.1
• /
• pp.80-90
• /
• 2016

Thanks to superior leakage energy efficiency compared to SRAM cells, STTRAM cells are considered as a promising alternative for a memory element in on-chip caches. However, the main disadvantage of STTRAM cells is high write energy and latency. In this paper, we propose a low-cost write filter (WF) cache which resides between the load/store queue and STTRAM-based L1 data cache. To maximize efficiency of the WF cache, the line allocation and access policies are optimized for reducing energy consumption of STTRAM-based L1 data cache. By efficiently filtering the write operations in the STTRAM-based L1 data cache, our proposed WF cache reduces energy consumption of the STTRAM-based L1 data cache by up to 43.0% compared to the case without the WF cache. In addition, thanks to the fast hit latency of the WF cache, it slightly improves performance by 0.2%.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.7
• /
• pp.1302-1308
• /
• 2002

Thermo-mechanical and flexural behavior of a wire-bond plastic ball grid array (WB-PBGA) package are characterized by high sensitive moire interferometry. Moire fringe patterns are recorded and analyzed for several bending loads and temperatures. At the temperature higher than $100^{\circ}C$, the inelastic deformation in solder balls become more dominant, so that the bending of the molding compound decreases while temperature increases. The deformation caused by thermally induced bending is compared with that caused by mechanical bending. The strain results show that the solder ball located at the edge of the chip has largest shear strain by the thermal load while the maximum average shear strain by the bending moment occurs in the end solder.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.857-862
• /
• 2003

In this paper, we concern for development of precise measuement system for civil structure by using one chip microprocessor based on communication system. The datalogger is developed by using 80C196KC microprocessor. It has RF communication modul and data acquisition function for several kinds of sensors such as load cell, tilt-meter, strain gauge, tension meter, themocouple and so on. The data is acquisited by datalogger is sent to a main server which is located at central monitoring office. The server has a function suppervising several data points located at civil structures, it analyzes the data and shows the data graphically. The effectiveness of the developed system is proven through experimental results by an application for the bridge of Nakdong river edge in Busan, Korea.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.3
• /
• pp.137-143
• /
• 2002

This paper presents the In-process compensation to control cutter runout and improve the machined surface quality. Cutter runout compensation system consists of the micro-positioning servo system with piezoelectric actuator which is embeded in the sliding table to manipulate radial depth of cut in real-time. Cutting force feedback control was proposed in the angle domain based upon repetitive learning control strategy to eliminate chip load variation in end milling process. Micro-positioning control due to adaptive actuation force response improves the machined surface quality by compensation runout effect induced cutting force variation. This result will provide lots of information to build-up the preciswion machining technology.