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Kai-hui Chen - One of the best experts on this subject based on the ideXlab platform.

  • Control IC for Boost-Flyback Converter for Energy Harvesting Applications
    2018 International Power Electronics Conference (IPEC-Niigata 2018 -ECCE Asia), 2018
    Co-Authors: Kai-hui Chen, Jui-hung Lai, Jun-xian Huang
    Abstract:

    Conventionally, boost Converter is used for high step-up energy harvesting system, but it is needed to be operated in discontinuous conduction mode (DCM) because of the limitation of the topology. Therefore, it causes more conduction loss and current stress on the switch. In this thesis, the control IC for boost-Flyback Converter in energy harvesting applications is proposed. It can greatly increase the voltage conversion ratio with the cascode of boost Converter and Flyback Converter. In addition, this topology can recycle the energy of the leakage inductance produced from coupled inductor to load. Thus, the efficiency can be increased and the stress on the main switch can be reduced. Finally, The boost-Flyback Converter with input voltage of 0.2-0.3 V, output voltage of 5 V and output power of 20 mW is implemented to verify the feasibility of the proposed controller.

  • Design of Quasi-resonant Flyback Converter control IC with DCM and CCM operation
    2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA), 2014
    Co-Authors: Kai-hui Chen, Tsorng-juu Liang
    Abstract:

    A Quasi-resonant (QR) Flyback Converter control IC is design and implemented. Flyback Converter is applied in small to medium power rating applications mostly, due to low cost and simple circuit topology. The conventional fix frequency operated Flyback Converter is the most adapted power Converter, but the switching losses cause lower conversion efficiency. The Flyback Converter can be operated in BCM and DCM by quasi-resonant control. The quasi-resonant control utilizes the resonant action between magnetize inductor of transformer and parasitic capacitor of power MOSFET to achieve valley voltage turn-on and reduce the turn on losses increasing the conversion efficiency. The switching frequency increases with reducing load, and the switching losses will cause poor efficiency. Flyback Converter operated in BCM and DCM in heavy load condition will lead to higher conduction losses. To improve the conversion efficiency at light load and heavy load condition, the proposed control circuit is integrated with frequency clamp and maximum off-time limit functions.

  • ISCAS - Losses analysis and low standby losses quasi-resonant Flyback Converter design
    2012 IEEE International Symposium on Circuits and Systems, 2012
    Co-Authors: Guan-chun Huang, Tsorng-juu Liang, Kai-hui Chen
    Abstract:

    In this paper, an AC-DC Flyback Converter with low power loss during low load condition is designed and implemented. A power loss model and breakdown of the quasi-resonant Flyback Converter is not only derived, but also analyzed with mathematic analysis software, MathCAD®. A new efficiency oriented burst mode control method is proposed to improve the system efficiency under standby condition. A laboratory prototype quasi-resonant Flyback Converter with universal range input voltage of 90∼264 V rms and output 24V/4.17A is implemented to verify the theoretical analysis. The power loss of the quasi-resonant Flyback Converter at 0.25 W load and 264 V rms is 160 mW that achieve the Energy Star Standard.

Guan-chun Huang - One of the best experts on this subject based on the ideXlab platform.

  • ISCAS - Losses analysis and low standby losses quasi-resonant Flyback Converter design
    2012 IEEE International Symposium on Circuits and Systems, 2012
    Co-Authors: Guan-chun Huang, Tsorng-juu Liang, Kai-hui Chen
    Abstract:

    In this paper, an AC-DC Flyback Converter with low power loss during low load condition is designed and implemented. A power loss model and breakdown of the quasi-resonant Flyback Converter is not only derived, but also analyzed with mathematic analysis software, MathCAD®. A new efficiency oriented burst mode control method is proposed to improve the system efficiency under standby condition. A laboratory prototype quasi-resonant Flyback Converter with universal range input voltage of 90∼264 V rms and output 24V/4.17A is implemented to verify the theoretical analysis. The power loss of the quasi-resonant Flyback Converter at 0.25 W load and 264 V rms is 160 mW that achieve the Energy Star Standard.

Tsorng-juu Liang - One of the best experts on this subject based on the ideXlab platform.

  • Design of Quasi-resonant Flyback Converter control IC with DCM and CCM operation
    2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA), 2014
    Co-Authors: Kai-hui Chen, Tsorng-juu Liang
    Abstract:

    A Quasi-resonant (QR) Flyback Converter control IC is design and implemented. Flyback Converter is applied in small to medium power rating applications mostly, due to low cost and simple circuit topology. The conventional fix frequency operated Flyback Converter is the most adapted power Converter, but the switching losses cause lower conversion efficiency. The Flyback Converter can be operated in BCM and DCM by quasi-resonant control. The quasi-resonant control utilizes the resonant action between magnetize inductor of transformer and parasitic capacitor of power MOSFET to achieve valley voltage turn-on and reduce the turn on losses increasing the conversion efficiency. The switching frequency increases with reducing load, and the switching losses will cause poor efficiency. Flyback Converter operated in BCM and DCM in heavy load condition will lead to higher conduction losses. To improve the conversion efficiency at light load and heavy load condition, the proposed control circuit is integrated with frequency clamp and maximum off-time limit functions.

  • ISCAS - Losses analysis and low standby losses quasi-resonant Flyback Converter design
    2012 IEEE International Symposium on Circuits and Systems, 2012
    Co-Authors: Guan-chun Huang, Tsorng-juu Liang, Kai-hui Chen
    Abstract:

    In this paper, an AC-DC Flyback Converter with low power loss during low load condition is designed and implemented. A power loss model and breakdown of the quasi-resonant Flyback Converter is not only derived, but also analyzed with mathematic analysis software, MathCAD®. A new efficiency oriented burst mode control method is proposed to improve the system efficiency under standby condition. A laboratory prototype quasi-resonant Flyback Converter with universal range input voltage of 90∼264 V rms and output 24V/4.17A is implemented to verify the theoretical analysis. The power loss of the quasi-resonant Flyback Converter at 0.25 W load and 264 V rms is 160 mW that achieve the Energy Star Standard.

Jeongpyo Park - One of the best experts on this subject based on the ideXlab platform.

  • quasi resonant qr controller with adaptive switching frequency reduction scheme for Flyback Converter
    IEEE Transactions on Industrial Electronics, 2016
    Co-Authors: Jeongpyo Park, Young Jin Moon, Mingyu Jeong, Jingyu Kang, Sanghyun Kim, Jungchul Gong, Changsik Yoo
    Abstract:

    A quasi-resonant (QR) controller with an adaptive frequency reduction scheme has been developed for a Flyback Converter. While maintaining the valley switching, the QR controller reduces the switching frequency for lighter load by skipping some valleys to reduce the power loss and thereby achieve better light-load efficiency. If the QR controller cannot detect any valley due to the damped oscillation of switch voltage, then the valley switching is given up and the nonvalley switching is employed to keep reducing the switching frequency for lighter load. The proposed QR controller has been implemented in a $\text{0.35}\hbox{-}\upmu\text{m}$ 700-V BCDMOS process and applied to a 40-W Flyback Converter. The power efficiency of the Flyback Converter is improved by upto 3.0% when the proposed QR controller is employed compared to the one employing the conventional QR controller.

  • a ccm dcm dual mode synchronous rectification controller for a high efficiency Flyback Converter
    IEEE Transactions on Power Electronics, 2014
    Co-Authors: Jeongpyo Park, Young Jin Moon
    Abstract:

    A dual-mode synchronous rectification (SR) controller supporting both the continuous-conduction mode and discontinuous-conduction mode is developed to improve the power efficiency of a Flyback Converter. The dual-mode SR controller ensures nonoverlapped turning-on of the primary and secondary switches by monitoring the voltage level of the secondary switch. The dual-mode SR controller requiring four pins and only one external resistor has been implemented in a 0.35-μm BCDMOS process and applied to a 50-W Flyback Converter. The efficiency of the Flyback Converter is improved by upto 6.8% when the dual-mode SR controller is employed compared to the one employing the conventional SR controller.

Jing-yuan Lin - One of the best experts on this subject based on the ideXlab platform.

  • An active-clamping ZVS Flyback Converter with integrated transformer
    2014 International Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE ASIA), 2014
    Co-Authors: Jing-yuan Lin, Chao-fu Wang, Huang-jen Chiu, Chien-yu Lin
    Abstract:

    This paper propose an active-clamping Flyback Converter using a integrated transformer. The proposed Converter is composed of two active-clamp Flyback Converter. The presented Converter can equally share the total load current between two secondaries so that the rectifier diode conduction loss can be decreased. Otherwise, the main switch of any Converter as auxiliary switch for the other one, so that only two switches are required and both can achieve zero-voltage-switching (ZVS) operation. The transformers of Converter are integrated into one magnetic core, therefore, the volume and copper loss of transformer can be reduced. Detailed analysis and design of this integrated magnetic active-clamping Flyback Converter are described. Experimental results are recorded for a prototype Converter with an AC input voltage ranging from 85 to 135 V, an output voltage of 24 V and an output current of 5 A, operating at a switching frequency of 100 kHz.

  • Analysis and design of a dual‐mode control Flyback Converter
    International Journal of Circuit Theory and Applications, 2012
    Co-Authors: Jing-yuan Lin, Chao-fu Wang
    Abstract:

    SUMMARY This letter presents a dual-mode control scheme to improve the efficiency of a Flyback Converter in a wide load range. The proposed Flyback Converter features a novel dual-mode operation. The valley-switching technique is adopted to reduce the switching loss at light load. On the other hand, the fixed off-time (FOT) controls with continuous conduction mode operations decrease the conduction losses at heavy load. The principles and design procedures of the proposed dual-mode controller are discussed and analyzed. Finally, a 140-W dual-mode Flyback Converter with an output voltage of 19 V is implemented. Experimental results agree with the theoretical analysis. Copyright © 2012 John Wiley & Sons, Ltd.

  • Analysis and design of a dual-mode Flyback Converter
    2010 IEEE International Conference on Sustainable Energy Technologies (ICSET), 2010
    Co-Authors: Jing-yuan Lin, Chao-fu Wang, Chien-yu Lin
    Abstract:

    This letter presents a dual-mode control scheme to improve the efficiency of a Flyback Converter in a wide load range. The proposed Flyback Converter features a novel dual-mode operation. The valley-switching technique is adopted to reduce the switching loss at light load. On the other hand, the fixed off-time (FOT) control with continuous conduction mode (CCM) operations decrease the conduction losses at heavy load. The principles and design procedures of the proposed dual-mode controller are discussed and analyzed. Finally, a 140-W dual-mode Flyback Converter with an output voltage of 19 V is implemented. Experimental results agree with the theoretical analysis.

  • active clamping zvs Flyback Converter employing two transformers
    IEEE Transactions on Power Electronics, 2007
    Co-Authors: Yukang Lo, Jing-yuan Lin
    Abstract:

    This paper presents a two-transformer active-clamping zero-voltage-switching (ZVS) Flyback Converter, which is mainly composed of two active-clamping Flyback Converters. By utilizing two separate transformers, the proposed Converter allows a low-profile design to be readily implemented while retaining the merits of a conventional single-transformer topology. The presented two-transformer active-clamping ZVS Flyback Converter can approximately share the total load current between two secondaries. Therefore, the transformer copper loss and the rectifier diode conduction loss can be decreased. Detailed analysis and design of this new two-transformer active-clamping ZVS Flyback Converter are described. Experimental results are recorded for a prototype Converter with an ac input voltage ranging from 85 to 135 V, an output voltage of 24 V and an output current of 8 A, operating at a switching frequency of 180 kHz.