EEFL (External Electrode Fluorescent Lamp) driving methods

EEFLs (External Electrode Fluorescent Lamps) are used as backlight source for large screen size LCDs. Since electrodes are outside of the discharge tube, lifetime is enhanced when compared with CCFLs (Cold Cathode Fluorescent Lamps) and a single inverter can drive multiple EEFL tubes and a compact design can be realized. EEFLs can be driven by both sinusoidal and square waveforms. Moreover, synchronizing the self-discharge time of the dielectric wall charge with the voltage rising and falling can enhance luminance. This paper presents luminance measurements for different driving alternatives and lamp voltages.