MFFL driving system with current feedback maintaining glow discharge mode

Recently, a mercury-free flat fluorescent lamp has been developed, utilizing glow discharge mode instead of discharge contraction. This paper proposes a lamp-driving system with a feedback loop which prevents the 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 in a normal operation level and suppress the long-term excitation causing the operation transfer to the contraction. The proposed method has been verified by hardware experiments which are compared to a conventional open-loop circuit by a discharge contraction time and the change of luminance.