| 摘要 |
PROBLEM TO BE SOLVED: To prevent dying out half-lit, activate light output rapidly, and curb electrode consumption. SOLUTION: Lamp applied voltage is controlled such that power value is, in starting, not more than nearly equal level with lamp applied power when a normal lamp is stably lit and is to be nearly equal level with lamp applied power when stably lit in a predetermined lamp voltage range. An output current I of a voltage-current converting circuit 100 is determined according to the following two equations expressing a continuous line; I=aV<SB>L</SB>+b (a, b: plus constant) when lamp voltage V<SB>L</SB>is not more than voltage V<SB>a</SB>lower than lamp voltage when the normal lamp is stably lit; I=cV<SB>L</SB>+d (c, d: plus constant, c<a, d>b) when the lamp voltage V<SB>L</SB>is not less than the voltage V<SB>a</SB>. The output current I of the voltage-current converting circuit 100 is expressed by I=I<SB>1</SB>+I<SB>2</SB>+I<SB>3</SB>. The fixed current I<SB>3</SB>of a current output part 400 is larger than output currents I<SB>1</SB>, I<SB>2</SB>of a first and a second converting parts 200, 300. COPYRIGHT: (C)2007,JPO&INPIT |
