Analysis and design considerations of LLCC resonant Dc-Dc converter with precise current sharing for two-channel LED driver

In this paper, a LLCC resonant converter with automatic precise current-sharing is proposed for two-channel LED driver. With a resonant capacitor connected in series with the transformer secondary winding, the currents of the two channels are precisely shared even for different LED strings with different voltage drops. The circuit operation principle, DC gain deduction and design considerations are discussed. A prototype of 140W two-channel LED driver is built to verify the proposed current sharing circuit.

[1]  M.M. Jovanovic,et al.  A novel LED driver with adaptive drive voltage , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[2]  Junming Zhang,et al.  A Simple Two-Channel LED Driver With Automatic Precise Current Sharing , 2011, IEEE Transactions on Industrial Electronics.

[3]  Pankaj Agarwal,et al.  Symmetric current balancing circuit for multiple DC loads , 2010, 2010 Twenty-Fifth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[4]  D.S. Zinger,et al.  Parallel connected LEDs operated at high to improve current sharing , 2004, Conference Record of the 2004 IEEE Industry Applications Conference, 2004. 39th IAS Annual Meeting..

[5]  Ke-Horng Chen,et al.  A high accuracy current-balanced control technique for LED backlight , 2008, 2008 IEEE Power Electronics Specialists Conference.

[6]  F. Lee,et al.  LLC resonant converter for front end DC/DC conversion , 2002, APEC. Seventeenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.02CH37335).

[7]  Heinz van der Broeck,et al.  Power driver topologies and control schemes for LEDs , 2007, APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition.

[8]  Zhaoming Qian,et al.  A Precise Passive Current Balancing Method for Multioutput LED Drivers , 2011, IEEE Transactions on Power Electronics.

[9]  Lilly Huang,et al.  Sensorless Current Sharing Analysis and Scheme For Multiphase Converters , 2008 .

[10]  S.Y.R. Hui,et al.  A comparative study on the circuit topologies for offline passive light-emitting diode (LED) drivers with long lifetime & high efficiency , 2010, 2010 IEEE Energy Conversion Congress and Exposition.

[11]  S. Hui,et al.  Comparative study on the structural designs of led devices & systems based on the general photo-electro-thermal theory , 2009, 2009 IEEE Energy Conversion Congress and Exposition.

[12]  S.Y.R. Hui,et al.  Comparative Study on the Structural Designs of LED Devices and Systems Based on the General Photo-Electro-Thermal Theory , 2010, IEEE Transactions on Power Electronics.

[13]  K. I. Hwu,et al.  A Simple Current-Balancing Converter for LED Lighting , 2009, 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exposition.