| 摘要 |
<p>PROBLEM TO BE SOLVED: To make feedback control of electric power supplied to a lamp from a battery while influence of a momentary change in the lamp current is well suppressed which is likely generated at changing over the direction of the discharge current. SOLUTION: In a lamp power circuit 10, a clamp circuit 69 is installed to maintain the voltage V1 fed to a lamp power control circuit 10 so that the lamp current IL becomes over a certain value. At changing over the discharge current of the lamp, the voltage V1 drops owing to a drop of the lamp current IL. Conventionally the feedback control has been made on the basis of the dropped V1, but according to the present invention, influence of a momentary change in the lamp current can be,, suppressed by maintaining V1 over the specified level by the clamp circuit 69.</p> |
