| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting circuit capable of controlling supply power with good reproducibility while suppressing the influence of a variation in voltage between electrodes caused by the individual difference or secular change of a discharge lamp. <P>SOLUTION: A discharge lamp lighting circuit 1 comprises a power supply unit 2 and a control unit 10a. The control unit 10a generates a control signal Sc for controlling an electric power value corresponding to a lamp voltage VL of a discharge lamp L. The power supply unit 2 supplies a power corresponding to a control signal Sc from the control unit 10a to the discharge lamp L. The control unit 10a includes a differential operation unit 15 which generates the first derivative signal Sd<SB>1</SB>(=dVS/dt) by temporal differentiation of a lamp voltage corresponding signal VS, and an integral operation unit 16 which generates the first integral signal Si<SB>1</SB>by time integration of the second differential signal Sd<SB>2</SB>which is monotonically increase and decrease with an increase and decrease of the first differential signal Sd<SB>1</SB>, and which generates a control signal Sc so as to decrease a supply power corresponding to an increase in the first integral signal Si<SB>1</SB>. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
