• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.1
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• pp.27-34
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• 2010

To dissipate the heat generated from the switching devices in the inverter system of HEV, the water cooling structure is proposed. The bolt type cooling structure has a problem such as water leakage for high pressure of water, therefore the proposed cooling structure applied pipe structure in the heat sink. The heat dissipation characteristics for various structures of water channel and distance between heat source and water channel was analyzed through the simulation. heat dissipation effect for two types of water cooling structures was investigated. Based on the simulation results, two types of water cooling system for 30kW inverter system of HEV were manufactured and the heat dissipation effect was verified.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.38-41
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• 2001

To reduce the wasted power with using an OP-AMP, 3 circuit supplying the same amount of power to load through overall voltage range can able proposed. With this type of design, the power that induced to the devices in the circuit will be reduced, we can also develope a small size power supply with the OP-AMP developed using this design. If we need a OP-AMP needed to handle higher power than usual, another design technique can be proposed. With substituting one device with the devices connected in series, the power loaded to each devices in the series devices can be reduced. This thesis contents the design of an OP-AMP to use in high power fields with small thermal dissipation.

• Journal of Industrial Technology
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• v.35
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• pp.41-45
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• 2015

This paper presents a development of the ELB (Electronic Leakage Breaker) based on a reduction of standby power dissipation as with maintaining conventional performance. In order to minimize the standby power consumption of the conventional circuit, we analyze the cause of 0.3W dissipation of the circuit. By employing the TR-triggered circuit to secure the standby power of 0.10W after testing and evaluation while CRD inserted circuit showed the performance of 0.17W levels. Implementing SMPS IC and TNR device circuit was designed and showed of its power to less than 0.06W. Developed ELB is expected much standby power savings in large power distributor or heavy users.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1988-1989
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• 2007

Polyethylene is widely used as the insulator for power cable. To investigate the conduction mechanism for power cable insulation under ac high field, it is very important to acquire the dissipation current under actual running field. Recently, we have developed the unique system, which make possible to observe the nonlinear dissipation current waveform. In this system, to observe the nonlinear properties with high accuracy, capacitive current component is canceled by using inverse capacitive current signal instead of using the bridge circuit for canceling it. We have already reported that the dissipation currents of $40\;{\mu}m$ thick LDPE film at 10 kV/mm and over 140 Hz, it starts to show nonlinearity and odd number's harmonics were getting large. To investigate the conduction mechanis ms in this region, especially space charge effect, various kinds of estimation, such as time variations of instantaneous resistivity for one cycle, FFT spectra of dissipation current waveforms and so on, has been examined. As the results of these estimations, it was found that the dissipation current will depend on not only the instantaneous value of electric field but also the time differential of applied electric field due to taking a balance between applied field and internal field. Furthermore, two large peaks of dissipation current for each half cycle were observed under certain condition. In this paper, to clarify the reason why it shows two peaks for each half cycle, the film thickness dependences of dissipation current waveforms were observed by using the three different thickness LDPE films.

• Journal of IKEEE
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• v.25 no.3
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• pp.528-533
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• 2021

This paper presents the PCB heat dissipation characteristics of high density DC-DC converter for electric vehicles. This paper also analyzes the heat dissipation structure of the high density DC-DC converter and optimizes the PCB heat dissipation design of the high density power system through thermal analysis simulation. Based on heat transfer theory, the thermal path of general electronic devices is analyzed and the thermal resistance equivalent circuit is modeled in this paper. Additionally, the thermal resistance equivalent circuit of the 500W synchronous buck converter, which is addressed in this paper, is modeled to present a structural heat dissipation path for better thermal performance. The validity of the proposed scheme is verified through the thermal analysis simulation results and experiments applying multi-surface heat dissipation structure to a 500[W](12[V], 41.67[A]) synchronous buck converter prototype with an input voltage 72[V].

• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.18-21
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• 2017

We report a method for improving heat exchange between cryo-cooled large-power-dissipation devices and liquid cryogen. Micro-machined monolithic heat sinks were fabricated on a high integration density superconducting Josephson device, and studied for their effect on cooling the device. The monolithic heat sink showed a significant enhancement of cooling capability, which markedly improved the device operation under large dc- and microwave power dissipation. The detailed mechanism of the enhancement still needs further modeling and experiments in order to optimize the design of the heat sink.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.699-702
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• 1998

This paper presents a 500MHz 1.1㎱ 32kb synchronous CMOS SRAM macro using $0.35\mu\textrm{m}$ CMOS technology. In order to operate at high frequency and reduce power dissipation, the designed SRAM macro is realized with optimized decoder, multi-point sense amplifier(MPSA), selective precharge scheme and etc. Optimized decorder and MPSA respectively reduce 50% and 40% of delay time. Also, a selective precharge scheme reduces 80% of power dissipation in that part.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.1
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• pp.10-14
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• 1998

In this paper a double edge triggered (DET) filp-flop is proposed which changes its output state at both the positive and the negative edge transitions of the triggering input. DET filp-flop has advantages in terms of speed and power dissipation over single edge triggered (SET) filp-flop has proposed DET flip-flop needs only 12 MOS transistors and can operate at clock speed of 500 MHz. Also, the power dissipation has decreased about 33% in comparison to SET flip-flop.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.113-114
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• 2006

In this paper, dual-gate mixer has been designed and optimized to have variable conversion gain for WiBro and WLAN applications and to save power. With the LO power of 0dBm and RF power of -50dBm, the mixer shows 15dB conversion gain. When RF power increases from -50dBm to -20dBm, the conversion gain decreases to -2dB with bias change. The variable conversion gain can reduce the high dynamic range requirement of AGC burden at IF stage. Also, it can save the dc power dissipation of mixer up to 90%.

• ETRI Journal
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• v.33 no.6
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• pp.880-886
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• 2011

With the introduction of high-current 8-inch solar cells, conventional Schottky bypass diodes, usually adopted in photovoltaic (PV) panels to prevent the hot spot phenomenon, are becoming ineffective as they cause relatively high voltage drops with associated undue power consumption. In this paper, we present the architecture of an active circuit that reduces the aforementioned power dissipation by profitably replacing the bypass diode through a power MOS switch with its embedded driving circuitry. Experimental prototypes were fabricated and tested, showing that the proposed solution allows a reduction of the power dissipation by more than 70% compared to conventional Schottky diodes. The whole circuit does not require a dedicated DC power and is fully compatible with standard CMOS technologies. This enables its integration, even directly on the panel, thereby opening new scenarios for next generation PV systems.