Electrical feedback control for driving mercury-free flat fluorescent lamp

Joung-Hu Park Jong-Bok Baek Bo-Hyung Cho Abstract — Recently, a mercury-free flat fluorescent lamp has been developed for LCD backlight application, utilizing a glow-discharge mode instead of a discharge contraction. This paper proposes a lamp-driving system with a feedback loop which prevents discharge contraction and stabilizes the operation of the lamp ignition and radiation. By measuring the current that flows through the lamp, the loop can adjust the current level to a normal operational level and suppress the long-term excitation that causes discharge contraction. The proposed method has been verified by hardware experiments which are compared to that of a conventional open-loop circuit by discharge contraction time and a change in luminance.