| 摘要 |
PURPOSE:To effectively supply power without an unstable arc in a lighting device for alternately supplying high frequency power and DC current to a high pressure discharge lamp by specifying the frequencies of the high frequency power and DC power. CONSTITUTION:A high frequency power with a frequency fHF and a chopper DC current with a frequency fDC are alternately supplied to a high pressure discharge lamp la through a serial circuit of a capacitor C1 parallel to the lamp la, an inductance element L1 serial to the capacitor C1, and a transistor circuit Q1, respectively. A relation of fDC>fHC>fLC (where fLC is a resonance frequency) is maintained. A lighting device having stable arc due to high fre quency components and having high efficiency is obtained, and the mode of an oscillation current turns to be a delay phase mode even at the time of DC operation, so stress in an switching element is reduced. |
