| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting circuit enabling a preferable gradually changing lighting in a low cost.SOLUTION: A control voltage generation part 30, when instructed to start lighting a light source 2, generates a control voltage Vthat increases with time. A drive circuit 20 supplies a lamp current Icorresponding to the control voltage Vto the light source. A potential of one end of a capacitor C11 is fixed, and the voltage between its both ends is the control voltage V. A charging circuit 32 supplies a variable charging current Ic to the capacitor C11. The charging circuit 32 reduces the charging current Ic more as the control voltage Vbecomes greater.SELECTED DRAWING: Figure 2 |
