A Study on the equivalent model of an External Electrode Fluorescent Lamp based on equivalent resistance and capacitance variation

An External Electrode Fluorescent Lamp (EEFL) has longer lifespan, higher power efficiency and higher luminance than a Cold Cathode Fluorescent Lamp (CCFL). Moreover, it is easy to drive them in parallel. Therefore, the EEFL is expected to quickly replace the CCFL in LCD backlight systems. However, the EEFL has more complex characteristics than the CCFL with a resistive component, because it has both a resistive component by plasma and a capacitive component by external electrode. In this paper, values of resistance and capacitance are measured at several power levels and at several operating frequencies. They are expressed by a numeral formula based on a linear approximation that represents the equivalent resistance and capacitance as a function of power. Then we made block diagram of the equivalent circuit model using numerical expressions. Simulation waveforms and experimental results are presented to verify the feasibility of the equivalent model.

[1]  Tsai-Fu Wu,et al.  A PSpice model for fluorescent lamps operated at high frequencies , 1995, Proceedings of IECON '95 - 21st Annual Conference on IEEE Industrial Electronics.

[2]  E. Choi,et al.  Glow discharge in the external electrode fluorescent lamp , 2005, IEEE Transactions on Plasma Science.

[3]  E. Choi,et al.  Capacitive coupled electrodeless discharge backlight driven by square pulses , 2002 .

[4]  U. Mader,et al.  A dynamic model for the electrical characteristics of fluorescent lamps , 1992, Conference Record of the 1992 IEEE Industry Applications Society Annual Meeting.

[5]  R.N. do Prado,et al.  Fluorescent lamp model employing tangent approximation , 2002, 2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289).

[6]  Dong-Seok Hyun,et al.  A new control scheme of unified power quality compensator-Q with minimum power injection , 2004, 30th Annual Conference of IEEE Industrial Electronics Society, 2004. IECON 2004.

[7]  Guangsup Cho,et al.  Self-discharge synchronizing operations in the external electrode fluorescent multi-lamps backlight , 2003 .

[8]  A.R. Seidel,et al.  Fluorescent lamp model employing tangent approximation , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).