• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.560-567
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• 2004

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 planar transformer, the decreased size and volume, the 300W ZVS forward converter with active clamp snubber circuit, 30W hard switching forward converter.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.110-113
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• 1993

The MOSFET synchronous rectification in the Active-Clamp Forward converter is presented. The Active-Clamp Forward converter has little dead time during the off time of the main switch and it is suitable for the MOSFET synchronous rectification comparing to the other Forward converter topologics. Using the MOSFET synchronous rectification on the Active-Clamp Forward converter with 3.3[V] output and 500[kHz] switching frequency, the improvement of efficiency is achieved comparing with the conventional Schottky barrier diode rectification.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.64-65
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• 2008

The topology of active clamp forward converter provides ZVS characteristic and also the stress of voltage and current is smaller than that of the conventional forward converters. The benefits of this technique include a higher efficiency at a high switching frequency, lower EMI/RFI. In this paper, the active clamp forward converter is designed for operation in wide range voltage and has 19.5V/120W ratings with efficiency more than 90%.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.5
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• pp.350-354
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• 2003

This study proposes a new self-driven active clamp forward converter eliminating the extra drive circuit for the active clamp switch. The converter used the auxiliary winding of the power transformer to drive the active clamp switch and a simple R-C circuit to get the dead time between the two switches. The operation principle was presented and experimental results were used to verify theoretical predictions. A 100-W (5V/20A) prototype converter built that only exhibited 1.5-turn winding number in the auxiliary winding was sufficient to drive the active clamp switch on the input of 50V. Finally, the measured efficiency of the converter was presented and the maximum efficiency of 91% was obtained.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.386-389
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• 2002

This paper proposes the boost input type active clamp forward ZVS(zero voltage switching) DC-DC converter which can provide high efficiency and improved EMI characteristics. Moreover, it has active clamp circuit for reducing the voltage stress and zero voltage switching technique for minimizing switching loss. The detailed operation principles and the simulation results are presented.

• Proceedings of the KIEE Conference
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• summer
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• pp.1235-1238
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• 2004

This paper presents the large-signal transient analysis of a self-driven active-clamp forward converter, eliminating the extra drive circuit for the active clamp switch. The operation principle of the converter was presented and experiential results were used to verify the analyzed results. A 50-W prototype converter built and tested it. From the tested results, input transient response and load transient response of the converter were established.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.6
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• pp.1064-1069
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• 2010

Active clamp forward converter provides zero voltage switching, low voltage stress and wide input voltage range. The design technique leads to getting a higher efficiency under high switching frequency and optimal operating range. It is designed for notebook computer adapter with free input voltage and 19.5V/120W output ratings. The efficiency is measured to more than 90%. One of the most important circuit parts is the filter inductor besides the transformer in active clamp forward converter. In this paper, the process of inductor design is listed optimally.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.3
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• pp.302-311
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• 2005

We propose an improved active forward converter by adding a non-dissipative snubber circuit to the secondary of the conventional active clamp forward converter in this paper. The snubber circuit is composed of a tapped inductor, a snubber capacitor, and two diodes. Comparing with the conventional one, the proposed one makes it possible ZVS to operate in a smaller magnetizing current condition. The operational principles and the equivalent mode analysis of an improved active forward converter are mentioned in this paper. In conclusion, we constructed the prototype of the modified active forward converter with 300W output capacity and verified higher efficiency compared to the conventional one.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.963_964
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• 2009

This paper presents an output ripple reduction of Active-Clamp Forward Converter, which is mainly composed of interleaving two active-clamping forward converters. By interleaving, Output ripple is reduced. The leakage inductance of the transformer or an additional resonant inductance is employed to achieve ZVS during the dead times. The duty cycles are not limited to be equal and within 50%. The complementary switching and the resulted interleaved output inductor currents diminish the current ripple in output capacitors. Accordingly, the smaller output chokes and capacitors lower the converter volume and increase the power density. Detailed analysis of this ouput reduction of Active-Clamp Forward Converter is described.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2020-2022
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• 1997

An active clamp forward converter is proper for minimization and basically makes high efficiency of the system because of soft switching type. Especially, when applied to forward converter, it widens the control range of duty ratio and is suitable for high input voltage. In other hand, the current doubler has high utility efficiency of transformer and reduces output current ripple because it always transfers the power through the transformer and has two inductor with opposite slope. So, this paper explained the conduction mode of an active clamp forward converter with the current doubler rectifier.