A Dimmable Light-Emitting Diode (LED) Driver With Mag-Amp Postregulators for Multistring Applications

Current imbalance should be avoided when multiple LED strings are connected in parallel. In this paper, a dimmable LED driver with magnetic-amplifier postregulators for multistring applications is presented. Powered by a common master source, parallel LED strings are individually regulated by their corresponding adaptive slave sources for current balancing in this proposal. Without linear current regulators, the proposed driver offers relatively high efficiency. Its structure is simpler than multiconverter structures for red, blue, and green LED applications, and is particularly suitable for LEDs with wide parameter variations. The performance of the proposed driver is experimentally verified by a 16.5-W prototype with a load of three 5.5-W LED strings.

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

[2]  Yu-Kang Lo,et al.  High-efficiency LED driver for street light applications , 2012, 2012 International Conference on Renewable Energy Research and Applications (ICRERA).

[3]  K. Schetters,et al.  A Power Management Unit With Integrated Stand-bySupply for Computer Motherboards:Control and VLSI Design , 2008, IEEE Transactions on Power Electronics.

[4]  Tsai-Fu Wu,et al.  Sequential Color LED Backlight Driving System for LCD Panels , 2007, IEEE Transactions on Power Electronics.

[5]  Y. T. Yau,et al.  Applying one-comparator counter-based sampling to current sharing control of multi-channel LED strings , 2010 .

[6]  Huang-Jen Chiu,et al.  LED Backlight Driving System for Large-Scale LCD Panels , 2007, IEEE Transactions on Industrial Electronics.

[7]  S. Muthu,et al.  Red, green and blue LED-based white light source: implementation challenges and control design , 2003, 38th IAS Annual Meeting on Conference Record of the Industry Applications Conference, 2003..

[8]  Simon S. Ang,et al.  A RGB-driver for LED display panels , 2010, 2010 Twenty-Fifth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[9]  Yu-Kang Lo,et al.  Design and Implementation of RGB LED Drivers for LCD Backlight Modules , 2009, IEEE Transactions on Industrial Electronics.

[10]  Yie-Tone Chen,et al.  Paralleling magamp-postregulator modules with sliding-mode-control method , 2006, IEEE Trans. Ind. Electron..

[11]  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).

[12]  S. Hui,et al.  A General Photo-Electro-Thermal Theory for Light Emitting Diode (LED) Systems , 2009, IEEE Transactions on Power Electronics.

[13]  Xiaohui Qu,et al.  Noncascading Structure for Electronic Ballast Design for Multiple LED Lamps With Independent Brightness Control , 2010, IEEE Transactions on Power Electronics.

[14]  S. Y. R. Hui,et al.  A novel passive off-line light-emitting diode (LED) driver with long lifetime , 2010, 2010 Twenty-Fifth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[15]  Xinbo Ruan,et al.  A Method of Reducing the Peak-to-Average Ratio of LED Current for Electrolytic Capacitor-Less AC–DC Drivers , 2010, IEEE Transactions on Power Electronics.

[16]  Regan Zane,et al.  Digital Architecture for Driving Large LED Arrays with Dynamic Bus Voltage Regulation and Phase Shifted PWM , 2007, APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition.

[17]  Tsai-Fu Wu,et al.  Multistring LED Backlight Driving System for LCD Panels With Color Sequential Display and Area Control , 2008, IEEE Transactions on Industrial Electronics.

[18]  S.-A. Liang,et al.  A new and simple structure of PC power supply with low cost and high efficiency to meet 80 plus requirement , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[19]  Xinbo Ruan,et al.  Means of Eliminating Electrolytic Capacitor in AC/DC Power Supplies for LED Lightings , 2009, IEEE Transactions on Power Electronics.

[20]  Dragan Maksimovic,et al.  Modeling of cross-regulation in multiple-output flyback converters , 1999, APEC '99. Fourteenth Annual Applied Power Electronics Conference and Exposition. 1999 Conference Proceedings (Cat. No.99CH36285).

[21]  Huang-Jen Chiu,et al.  A High-Efficiency Dimmable LED Driver for Low-Power Lighting Applications , 2010, IEEE Transactions on Industrial Electronics.

[22]  R. Zane,et al.  LED Driver Circuit with Series-Input-Connected Converter Cells Operating in Continuous Conduction Mode , 2010, IEEE Transactions on Power Electronics.

[23]  J. Pleite,et al.  PWM-PD multiple output DC/DC converters: operation and control-loop modeling , 2004, IEEE Transactions on Power Electronics.

[24]  C. K. Michael Tse,et al.  Temperature Measurement Technique for Stabilizing the Light Output of RGB LED Lamps , 2010, IEEE Transactions on Instrumentation and Measurement.

[25]  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.

[26]  C.K. Tse,et al.  On Driving Techniques for LEDs: Toward a Generalized Methodology , 2009, IEEE Transactions on Power Electronics.

[27]  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..

[28]  Yen-Shin Lai,et al.  Novel AC Driver and Protection Circuits with Dimming Control for Light Emitting Diodes , 2007, 2007 IEEE Industry Applications Annual Meeting.

[29]  Chin-Yang Wu,et al.  Fast Transition Current-Type Burst-Mode Dimming Control for the LED Back-Light Driving System of LCD TV , 2006 .

[30]  M.M. Jovanovic,et al.  LED Driver With Self-Adaptive Drive Voltage , 2008, IEEE Transactions on Power Electronics.

[31]  C.K. Tse,et al.  Bilevel Current Driving Technique for LEDs , 2009, IEEE Transactions on Power Electronics.