| 摘要 |
PURPOSE:To stabilize the output light in a short period of time by supplying the power at the time of starting, first in an amount several time as large as the rating until the lamp voltage attains the No.1 specified value, and then according to a specific formula until the lamp voltage attains the No.2 specified value, and thereafter decreasing the power by a certain amount at each unitary interval time until the converter output power becomes a specified value. CONSTITUTION:At starting, a high voltage generator circuit 10 generates a high voltage to light up a discharge lamp 8, and a lap state sensing circuit 7 senses the lamp current while a power sensing circuit 4 senses power information. A control circuit 3 controls a DC-DC converter 2 in conformity to information of circuits 4, 7 to supply the lamp 8 with a power several times as large as the rating until the lamp voltage attains the specified value. The control circuit 3 also controls so that the converter 2 power becomes the starting power subtracted by the lamp voltage which is multiplied with specified current until the lamp voltage becomes the No.2 specified value. Thereafter the control circuit 3 decreases the output power of the converter 2 by a certain amount at each until interval time so as to maintain the rated power finally. Thereby the output light is stabilized in a short period of time. |
