| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device and an illumination device with stability improved at the time of light-control lighting of a discharge lamp. <P>SOLUTION: A direct-current superimposition circuit 1 superimposes a direct-current voltage on an alternating current voltage impressed on a fluorescent lamp FL. A light control signal correction circuit K1 inputs a detection value of a direct-current voltage detection circuit 2 and a light control signal Vs1 from outside. If the detection value of the direct-current voltage detection circuit 2 surpasses a first threshold value Vth1, it outputs a light control signal VsO of a higher level than the light control signal Vs1, and if the detection value of the direct-current voltage detection circuit 2 falls short of a second threshold value Vth2 which is less than the first threshold value Vth1, it decreases a level of the light control signal VsO to be outputted down to the light control signal Vs1 inputted. Then, in accordance with variations of levels of the light control signal VsO outputted by the light control signal correction circuit K1, an inverter circuit INV varies power volumes of alternating currents supplied to the fluorescent lamp FL to control light of the fluorescent lamp FL. <P>COPYRIGHT: (C)2008,JPO&INPIT |
