Balanced Driving System for Multiple Cold-Cathode Fluorescent Lamps

A novel circuit with dual-high-voltage topology to drive cold-cathode fluorescent lamps (CCFLs) for liquid crystal display (LCD) backlight modules is proposed in this paper. In the proposed circuit topology, all the lamps are connected in series to alleviate the influence of parasitic capacitance induced between the lamps and the aluminum backplank. Balance lamp current and uniform light output can be achieved without using any current balancing circuit. The circuit topology is capable of driving arbitrarily even numbers of lamps with same lamp current while achieving significant reduction in size, weight, and cost. The circuit is verified by experimenting on a backlight module with four L-type lamps in a 19-inch LCD. The experimental results demonstrate the effectiveness and feasibility.

[1]  Yi-Hwa Liu,et al.  Design and Implementation of an FPGA-Based CCFL Driving System With Digital Dimming Capability , 2007, IEEE Transactions on Industrial Electronics.

[2]  R.-L. Lin,et al.  Current-Equalization Techniques for Electronic Ballasts , 2007, IEEE Transactions on Power Electronics.

[3]  F.T. Wakabayashi,et al.  An improved design procedure for LCC resonant filter of dimmable electronic ballasts for fluorescent lamps, based on lamp model , 2005, IEEE Transactions on Power Electronics.

[4]  Gyu-Hyeong Cho,et al.  Mixed Mode Excitation and Low Cost Control IC for Electronic Ballast , 2007, IEEE Transactions on Power Electronics.

[5]  C. S. Moo,et al.  Electronic ballast with piezoelectric transformer for cold cathode fluorescent lamps , 2003 .

[6]  H.S.H. Chung,et al.  Self-oscillating dimmable electronic ballast for fluorescent lamps , 2004, IEEE Power Electronics Letters.

[7]  Three-Phase Electronic Ballast With Current-Equalization Function , 2006, Journal of Display Technology.

[8]  Fred C. Lee,et al.  New continuous-input current charge pump power-factor-correction electronic ballast , 1999 .

[9]  S. Hui,et al.  Practical evaluation of dimming control methods for electronic ballasts , 2003, 38th IAS Annual Meeting on Conference Record of the Industry Applications Conference, 2003..

[10]  S. Ben-Yaakov,et al.  Cold Cathode Fluorescent Lamps Driven by Piezoelectric Transformers: Stability Conditions and Thermal Effect , 2007, IEEE Transactions on Power Electronics.

[11]  Bo-Hyung Cho,et al.  Analysis of Current Distribution in Driving Multiple Cold Cathode Fluorescent Lamps (CCFL) , 2007, IEEE Transactions on Industrial Electronics.

[12]  C. Branas,et al.  Microcontroller Power Mode Stabilized Power Factor Correction Stage for High Intensity Discharge Lamp Electronic Ballast , 2007, IEEE Transactions on Power Electronics.

[13]  Eyup Akpinar,et al.  Transformerless Single Phase Inverter Design for LCD Television , 2007, IEEE Transactions on Consumer Electronics.

[14]  Wei-Chung Cheng,et al.  Power minimization in a backlit TFT-LCD display by concurrent brightness and contrast scaling , 2004, IEEE Transactions on Consumer Electronics.

[15]  Tsai-Fu Wu,et al.  Multiphase driving system for LCD back-light lamps with current balancing feature , 2006 .

[16]  Chang-Hua Lin.  The design and implementation of a new digital dimming controller for the backlight resonant inverter , 2005, IEEE Transactions on Power Electronics.

[17]  Gyu-Hyeong Cho,et al.  A control IC for electronic ballast with mixed-mode excitation , 2004, 2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551).

[18]  Henry Shu-Hung Chung,et al.  A comparative study on dimming control methods for electronic ballasts , 2001 .

[19]  Sang Kyung Kim,et al.  A Low-Cost High-Efficiency CCFL Inverter With New Capacitive Sensing and Control , 2006, IEEE Transactions on Power Electronics.

[20]  Wen-Jung Ho,et al.  A cold-cathode fluorescent lamp driver circuit with synchronous primary-side dimming control , 1998, IEEE Trans. Ind. Electron..