A Single-Stage High-Power-Factor LLC Resonant AC-DC Converter for Light Emitting Diode Driving

2012 ◽  
Vol 8 (1) ◽  
pp. 451-456 ◽  
Author(s):  
Chien-Hsuan Chang ◽  
Chun-An Cheng ◽  
Hung-Liang Cheng ◽  
Hung-Yi Chen
Keyword(s):  
Power Factor ◽  
High Power ◽  
Light Emitting Diode ◽  
Single Stage ◽  
Light Emitting ◽  
High Power Factor

scholarly journals A Single-Stage High-Power-Factor Light-Emitting Diode (LED) Driver with Coupled Inductors for Streetlight Applications

2017 ◽  
Vol 7 (2) ◽  
pp. 167 ◽  
Author(s):  
Chun-An Cheng ◽  
Chien-Hsuan Chang ◽  
Hung-Liang Cheng ◽  
Ching-Hsien Tseng ◽  
Tsung-Yuan Chung
Keyword(s):  
Power Factor ◽  
High Power ◽  
Light Emitting Diode ◽  
Single Stage ◽  
Led Driver ◽  
Light Emitting ◽  
Coupled Inductors ◽  
High Power Factor

scholarly journals A Novel Single-Switch Single-Stage LED Driver with Power Factor Correction and Current Balancing Capability

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1340
Author(s):  
Yih-Her Yan ◽  
Hung-Liang Cheng ◽  
Chun-An Cheng ◽  
Yong-Nong Chang ◽  
Zong-Xun Wu
Keyword(s):  
Power Factor ◽  
High Power ◽  
Pulse Width Modulation ◽  
Power Factor Correction ◽  
Harmonic Distortion ◽  
Boost Converter ◽  
Single Stage ◽  
Led Driver ◽  
Flyback Converter ◽  
High Power Factor

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.

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