An Adaptive Output Current Estimation Circuit for a Primary-Side Controlled LED Driver
2012; Institute of Electrical and Electronics Engineers; Volume: 28; Issue: 10 Linguagem: Inglês
10.1109/tpel.2012.2236581
ISSN1941-0107
AutoresHsiao-Hsing Chou, Yuh‐Shyan Hwang, Jiann‐Jong Chen,
Tópico(s)Multilevel Inverters and Converters
ResumoA primary-side controlled method is commonly used in flyback LED driver to regulate output current by employing an auxiliary winding. However, owing to intrinsic propagation delay in real-world circuits, a primary-side controlled flyback converter experiences a worse line regulation. This paper proposes a smart output current estimation scheme to improve line regulation for constant on-time control, and it can be compatible with the current flyback topology. A 9.5-W prototype of the proposed flyback LED driver has been fabricated in Nuvoton Technology Corporation 0.6-μm 5-V/40-V CMOS process. The maximum switching frequency is set to around 100 kHz with universal-line input, single-stage power factor correction for LED lighting applications. Experimental results prove that the proposed scheme can improve the line regulation within 1.5% and the power efficiency can be up to 89.7%.
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