• Journal of Power Electronics
• /
• v.19 no.3
• /
• pp.645-654
• /
• 2019

In this paper, a new high step up DC/DC converter with a modified super-lift technique is presented. The coupled inductor technique is combined with the super-lift technique to provide a tenfold or more voltage gain with a proper duty cycle and a low turn ratio. Due to a high conversion ratio, the voltage stress on the semiconductor devices is reduced. As a result, low voltage ultra-fast recovery diodes and low on resistance MOSFET can be used, which improves the reverse recovery problems and conduction losses. This converter employs a passive clamp circuit to recycle the energy stored in the leakage inductance. The proposed convertor features a high conversion ratio with a low turn ratio, low voltage stress, low reverse recovery losses, omission of the inrush currents of the switch capacitor loops, high efficiency, small volume and reduced cost. This converter is suitable for renewable energy applications. The operational principle and a steady-state analysis of the proposed converter are presented in details. A 200W, 30V input, 380V output laboratory prototype circuit is implemented to confirm the theoretical analysis.

• ETRI Journal
• /
• v.35 no.3
• /
• pp.554-557
• /
• 2013

This letter presents a power amplifier (PA) with an on-chip power detector for 2.4-GHz wireless local area network application. The power detector consists of a clamp circuit, a diode detector, and a coupled line directional coupler. A series inductor for an output matching network in the PA is combined with a through line of the coupler, which reduces the coupling level. Therefore, the coupler employs a metamaterial-based transformer configuration to increase coupling. The amount of coupling is increased by 2.5 dB in the 1:1 symmetric transformer structure and by 4.5 dB from two metamaterial units along the coupled line.

• Proceedings of the KIEE Conference
• /
• 1997.07f
• /
• pp.2016-2019
• /
• 1997

To solve the low efficiency problem of low-voltage power supplies, it has been studied to replace the schottky barrier diode with the MOSFET synchronous rectifier. In this paper, Phase Shift-Controlled Clamp Mode Zero Voltage Switching-Multi Resonant Converter with Synchronous Rectifier (PSC CM ZVS-MRC with SR) is presented to achieve high efficiency in low-voltage power supplies. The characteristics analysis of synchronous rectifier is established by using the MOSFET equivalent circuit and efficiency comparison is established between the Synchronous Rectifier and the schottky barrier diode. To verify the validity of the analysis, 33W(3.3V, 10A) PSC CM ZVS-MRC with self-driven synchronous rectifier at switching frequency of 1MHz is designed and tested. And it is confirmed that the experimental results are well consistent with the theoretical results. The maximum efficiency of the converter is 83.4% at full load, which is 3.3% higher than conventional schottky diode rectification.

• Development and Reproduction
• /
• v.16 no.4
• /
• pp.265-270
• /
• 2012

Ethanol actions in the amygdala formation may underlie in part the reinforcing effects of ethanol consumption. Previously a physiological phenomenon in the basolateral amygdala (BLA) that is dependent on neuronal network activity, compound postsynaptic potentials (cPSPs) were characterized. Effects of acute ethanol application on the frequency of cPSPs were subsequently investigated. Whole cell patch clamp recordings were performed from identified projection neurons in a rat brain slice preparation containing the amygdala formation. Acute ethanol exposure had complex effects on cPSP frequency, with both increases and decreases dependent on concentration, duration of exposure and age of the animal. Ethanol produces complex biphasic effects on synaptically-driven network activity in the BLA. These findings may relate to subjective effects of ethanol on arousal and anxiolysis in humans.

• Proceedings of the KIPE Conference
• /
• 2006.06a
• /
• pp.384-386
• /
• 2006

본 논문에서는 AC Plasma display panel(AC-PDP) 구동을 위한 Six-switch를 적용한 Three-level PDP Sustain 회로를 제안한다. 제안 회로는 기존 회로의 Sustain 스위치와 Clamp 다이오드의 내압이 절반이 되어 특성이 우수한 반도체 소자의 채택이 가능하며, 환류 전류가 저감되어 높은 전력 효율을 가지는 장점을 가지므로 AC-PDP 구동 회로 설계에 매우 적합하다. 본 논문에서는 기존 회로와 제안 회로의 전도 손실 계산 및 시뮬레이션과 실험 결과를 보였다.

• Proceedings of the KIPE Conference
• /
• 2003.11a
• /
• pp.149-153
• /
• 2003

In this paper, the design and implementation of a high power(300W) forward converter using a planar transformer is presented. The overall size and volume of the converter is decreased by replacing a planar transformer in stead of using a conventional winding transformer. Due to the decreased size and volume, power density of the applied forward converter is increased. Also, in this paper, the 300W ZVS forward converter with active clamp snubber circuit is compared to the 300W hard switching forward converter.

• Proceedings of the KIEE Conference
• /
• 2002.11d
• /
• pp.171-173
• /
• 2002

This paper describes the open frame type high power density switching converter. It is based on active clamp forward converter with synchronous rectifier, and packaged by using the open frame and multi-layer printed circuit board (PCB) techniques to achieve the high power density. Furthermore, windings of transformer and inductor are also realized by multi-layer PCB so that it achieves the higher power density. Through the experiment on the proto-type converter of 50[W], it is confirmed that power density of $50[W/in^3]$ and maximum efficiency of over 91 [%] are obtained.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.1057-1058
• /
• 2006

In this paper, the proposed power supply is based on a modified version of the zero-voltage switching(ZVS) full-bridge phase-shift DC-DC converter, which incorporates commutation auxiliary inductors to provide ZVS for the entire load range as well as a commutation aid circuit to clamp the output diode voltage. The control strategy is based on two control loops operating in cascade mode. The complete operating principles and simulation results in presented.

• Proceedings of the KIPE Conference
• /
• 2008.06a
• /
• pp.206-208
• /
• 2008

본 논문에서는 5kW급 이상의 연료전지 PCS를 위한 3상 DC-DC 컨버터를 제안한다. 제안한 컨버터는 승압비가 매우 높고 듀티를 0에서 1까지 사용하므로 변압기등 주요 소자를 최적으로 설계할 수 있다. 또한 전류원이면서도 클램프 회로와 스타트-업 회로가 필요 없을 뿐만 아니라 넓은 부하영역에서 영전압 턴 온이 가능하다. 기존 3상 컨버터와의 비교 분석을 수행하였으며 실험을 통해 본 방식의 타당성을 검증하였다.

• Journal of Power Electronics
• /
• v.16 no.3
• /
• pp.894-904
• /
• 2016

This study examines the zero-voltage switching (ZVS) operation of an active-clamped forward converter (ACFC) with a current-doubler rectifier (CDR). The ZVS condition can be obtained with a much smaller leakage inductance compared to that of a conventional ACFC. Due to the significantly reduced leakage inductance, the design is optimized and the circulating loss is reduced. The operation of the ACFC with a CDR is analyzed, and a detailed ZVS analysis is conducted on the basis of a steady-state analysis. From the results, a design consideration for ZVS improvement is presented. Loss analyses of the converters shows that enhanced soft-switching contributes to an efficiency improvement under light-load condition. Experimental results from a 100-W (5-V/20-A) prototype verify that the ACFC with a CDR can attain ZVS across an extended load range of loads and achieve a higher efficiency than conventional ACFCs.