| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique which allows for stable variable control of the output voltage from a PFC circuit, while preventing temperature rise of the circuit components.SOLUTION: When starting to light a lamp 96, a reference voltage for high voltage in a memory 1345 is outputted to a difference calculation unit 1342 by a reference voltage calculation unit 1343, and time measurement is started in a clock unit 1344. The output voltage from a PFC circuit 13 is controlled so as to become the reference voltage for high voltage, and inputted to a high voltage circuit 951 for lighting the lamp. A high voltage lamp voltage is outputted, from the high voltage circuit 951 for lighting the lamp, by the reference voltage for high voltage and discharged in the lamp 96. When the fact that a predetermined time has reached from the starting to light a lamp is notified from the clock unit 1344, a normal reference voltage corresponding to an input AC voltage is outputted from the memory 1345 to the difference calculation unit 1342 by the reference voltage calculation unit 1343, and the output voltage from the PFC circuit 13 is controlled to the normal reference voltage. A ballast circuit 952 performs constant power control of the lamp voltage by the normal reference voltage. |
