scholarly journals A Two Stage Buck Boost Converter With Isolation As A High Power Factor Supply For Power-LED Lamps

Author(s):  
Lekshmi Sasidharan, ◽  
Jeneesh Scaria
2014 ◽  
Vol 971-973 ◽  
pp. 1206-1209
Author(s):  
Ying Ying Song ◽  
Hong Min Wang ◽  
Ling Yu ◽  
Feng Wu Su

A 100W adaptor with universal voltage range 90-265VAC input and 20V/5A output is designed in this paper .The prototype adopted a new level two-stage high power factor power adapter, the PFC(Power Factor Correction) is a Boost converter operating in discontinuous current mode boundary,and the DC/AC using flyback converters. The experimental results showed that the effectiveness of the proposed approach.


Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1340
Author(s):  
Yih-Her Yan ◽  
Hung-Liang Cheng ◽  
Chun-An Cheng ◽  
Yong-Nong Chang ◽  
Zong-Xun Wu

A novel single-switch single-stage high power factor LED driver is proposed by integrating a flyback converter, a buck–boost converter and a current balance circuit. Only an active switch and a corresponding control circuit are used. The LED power can be adjusted by the control scheme of pulse–width modulation (PWM). The flyback converter performs the function of power factor correction (PFC), which is operated at discontinuous-current mode (DCM) to achieve unity power factor and low total current harmonic distortion (THDi). The buck–boost converter regulates the dc-link voltage to obtain smooth dc voltage for the LED. The current–balance circuit applies the principle of ampere-second balance of capacitors to obtain equal current in each LED string. The steady-state analyses for different operation modes is provided, and the mathematical equations for designing component parameters are conducted. Finally, a 90-W prototype circuit with three LED strings was built and tested. Experimental results show that the current in each LED string is indeed consistent. High power factor and low THDi can be achieved. LED power is regulated from 100% to 25% rated power. Satisfactory performance has proved the feasibility of this circuit.


1994 ◽  
Vol 114 (11) ◽  
pp. 1139-1148 ◽  
Author(s):  
Michihiko Nagao ◽  
Takashi Nakakohara ◽  
Masahito Jinno ◽  
Koosuke Harada

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