| 摘要 |
PROBLEM TO BE SOLVED: To enable to adapt to a wide operating temperature range required for lighting outdoors or for vehicle use and to realize compactness with a simplified circuit, in a discharge lamp lighting device using a piezoelectric transformer. SOLUTION: The device is provided with a piezoelectric transformer T1 supplying ac voltage impressed on a primary electrode after voltage conversion to discharge lamp load RL connected to a secondary electrode, a coil L1 connected in series with the primary electrode of the piezoelectric transformer T1, a power source circuit supplying ac voltage to a series circuit network consisting of the piezoelectric transformer T1 and the coil L1, a frequency control circuit 2 controlling so that the frequency fr of the ac voltage roughly coincide with that fp at which step-up ratio of the piezoelectric transformer gets maximum. Further, it is desirable that resonance frequency fk determined by the input capacitance Cp1 of the piezoelectric transformer T1 and inductance of the coil L1 satisfy fk<0.8fr against the frequency fr of the ac voltage. |
