An Adaptive Output Current Estimation Circuit for a Primary-Side Controlled LED Driver

作者：Chou Hsiao Hsing^*; Hwang Yuh Shyan; Chen Jiann Jong

来源：IEEE Transactions on Power Electronics, 2013, 28(10): 4811-4819.

DOI：10.1109/TPEL.2012.2236581

• Flyback converter
• light-emitting diode (LED) driver
• line regulation
• primary-side controlled

A 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-mu m 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%.

• 出版日期2013-10