Analysis of Inverter Circuit with External Electrode Fluorescent Lamps for LCD Backlight

The circuit of the EEFL system and the inverter has been analyzed into the resistance RL, the capacitance C of the EEFL-backlight system, and the inductance of transformer in the inverter. The lamp resistance and capacitance are deter-mined from the phase difference is between the lamp current and voltage and from the Q-V diagram, respectively. The single Lamp of EEFL for 32' LCD-BLU has the resistance of and the capacitance of 21.61 pF. The resistance, which is connected by parallel in the 20-EEFLS BLU, is and the capacitance is 402.1 pF. The matching frequency in the operation of lamp system is noted as , where is the inductance of secondary coil and k is the coupling coefficient between primary and secondary coil. The lamp current and voltage has maximum value at the matching frequency in the LCD BLU system. The results of analytic solutions are in good agreement with the experimental results.