| 摘要 |
PROBLEM TO BE SOLVED: To reduce starting voltage applied to both ends of a lamp as viewed from a peak-to-peak value, reduce the cost of a lighting device, and realize the miniaturization by combining a lamp having uneven resistance distribution in the discharge path in a tube wall and a ballast circuit having asymmetric positive and negative output voltages, and decreasing the DC component at the start of lighting the lamp. SOLUTION: Only when starting voltage is applied, a switching element Q3 is turned off to make apply of DC voltage to a lamp zero. The switching element Q3 is controlled with a timer circuit IC3, at almost the same time as completion of preheating time, an off signal is given to the switching element Q3, and when prescribed starting voltage applied time is elapsed, an on signal is given to the switching element Q3. A state of starting is more surely conducted, and peak-to-peak voltage (VPP) at the opposite ends of the lamp at start is reduced. Preferably, impedance in a current line path where a CD component is superimposed on the lamp is controlled so as to increase at least at starting. |
