• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.166-170
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• 2003

This paper presents the TTFC(Two Transistor Forward Converter) using Synchronous Rectifier of Compulsory Control-driver. The two transistor forward circuit is used to decrease voltage stress of primary side and the synchronous rectifier is used to reduce current stress of secondary side. Previous synchronous rectifier's MOSFET of TTFC have long dead time This paper presents synchronous rectifier of compulsory control-driver for minimized dead time. This paper compared with diode rectifier, self-driven synchronous rectifier and compulsory control-driver synchronous rectifier of TTFC. The principle of operation, feature and design considerations are illustrated and verified through the experiment with a 200W 100kHz MOSFET based experimental circuit.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.178-181
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• 2005

This paper presents a synchronous rectifier in a LLC half bridge topology. The proposed synchronous rectifier is used to a current driven synchronous rectifier(SR). If FET is driven without dead times. Voltage driven synchronous rectifier may introduce voltage and current surge during the zero dead times. To solve this problem, we propose to use modified current driven synchronous rectifier. Finally, the prototype is built and comparison on the current and voltage driven synchronous rectifier(SR).

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

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.112-120
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• 1997

The clamp mode (CM) forward zero voltage switching multi resonant converter (ZVS-MPC) with self-driven synchronous rectifier is studied. The loss at the synchronous rectification stage of the converter is analyzed using MOSFET piecewise linear model and is compared with the loss at the conventional schottky diode rectification stage of th econverter. From the results of the analysis, it is known that the use fo MOSFETs as a synchronous rectifier reduces the loss at the rectification stage overthe whole load range comparing the use of schottky diodes as a conventional rectifier in the converter. In order to verify the validit of the analysis, we have built a 33W(3.3V/10A) CM forward ZVS-MRC with self-driven synchronous rectifier, in which switching frequency is 1MHz, and tested. FRom the experimental results, it is known that the synchronous rectification achieved about 1W improvement in the loss at the rectification stage and about 3% in the efficiency at the converter as compared with the conventional schottky diode rectification.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.295-297
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• 2005

This paper presents a novel current driving method for the synchronous rectifier (SR) in a Flyback topology. The proposed current driven synchronous rectifier features low Power loss, good performance and the gate voltage of FET in the synchronous rectifier is easily controlled by zener voltage. The proposed SR driving method is implemented in a 200W Flyback converter with 400Vdc input and achieved excellent performance at full load.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1395-1397
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• 2005

This paper presents a novel current driving method for the synchronous rectifier(SR) in a flyback topology. The proposed current driven synchronous rectifier features low power loss, good performance and the gate voltage of FET in the synchronous rectifier is easily controlled by resistor ratio. The proposed SR driving method is implemented in a 200W Flyback converter with 400Vdc input and achieved excellent performance at full load.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.79-86
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• 2016

In this paper, we propose a current-driven synchronous rectifier driver circuit for LLC resonant half-bridge converters. The proposed driver circuit detects a relatively low current in the primary side of the transformer although a large current is flowing in the secondary side. Due to this feature, the driver circuit has a simple circuit structure and stabilizes the switching operation with a logic-level switching voltages for the synchronous rectifier. The operation and performance of the proposed driver circuit are confirmed with a prototype of 1kW class LLC resonant half-bridge converter. The experimental results proved that the proposed synchronous rectifier driver method improves the power conversion efficiency by around 1% and reduces the internal power loss by 17W.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.361-370
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• 2006

A single-stage single-switch flyback converter with synchronous rectifier is proposed. The proposed single-stage single-switch technique meets the IEC 61000-3-2 harmonic requirements. The proposed SR is the voltage driven synchronous rectifier (VDSR) which operates depending on the voltage drop across the drain and source of the MOSFET. Experimental results for the 85W (12V /7.1A) proposed converter are shown.

• Journal of Power Electronics
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• v.18 no.2
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• pp.604-614
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• 2018

This paper proposes a synchronous switching technique for a Vienna rectifier that uses carrier-based pulse width modulation (CB-PWM). A three-phase Vienna rectifier, similar to a three-level T-type converter with three back-to-back switches, is used as a PWM rectifier. Conventional CB-PWM requires six independent gate signals to operate back-to-back switches. When internal switches are operated synchronously, only three independent gate signals are required, which simplifies the construction of gate driver circuits. However, with this method, total harmonic distortion of the input current is higher than that with conventional CB-PWM switching. A reactive current injection technique is proposed to improve current distortion. The performance of the proposed synchronous switching method and the effectiveness of the reactive current injection technique are verified using simulations and experiments performed with a set of Vienna rectifiers rated at 5 kW.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.395-399
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• 1996

The Clamp Mode(CM) Forward Zero Voltage Switching Multi Resonant Converter(ZVS-MRC) with self-driven synchronous rectifier in studied. The loss at the synchronous rectification stage of the converter is analyzed using MOSFET linear model and is compared with the loss at the conventional schottky diode rectification stage of the converter. From the results of the analysis, it is known that the use of MOSFETs as a synchronous rectifier reduces the loss at the rectification stage over the whole load range comparing the use of schottky diodes as a conventional rectifier in the converter. In order to verify the validity of the analysis, we have built a 33W(3.3V/10A) CM Forward ZVS-MRC with self-driven synchronous rectifier, in which switching frequency is 1MHz, and tested. From the experimental results, it is known that the synchronous rectification achieved about 1W improvement in the loss at the rectification stage and about 3% in the efficiency at the converter as compared with the conventional schottky diode rectification.