| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a light source driving voltage control device with small circuit scale alleviating flicker of a light source at the time of restoration to its normal state after a drastic change of power source voltage. <P>SOLUTION: An initial drive voltage is set for setting required brightness of the light source below the power source voltage. After the light source 12 is driven with the initial drive voltage as a light source drive voltage, a CPU 11 judges whether a power source voltage Vin has fallen below the initial drive voltage V<SB>LAMP</SB>or not. When the power source voltage gets below the initial drive voltage, the CPU retains a power source voltage fall information to the effect that the power source voltage has fallen with the power source voltage as the light source drive voltage, and after the power source voltage fall information is retained, the light source driving voltage is gradually restored back to the initial driving voltage, at the instant the power source voltage is judged to be restored to a voltage higher than the initial driving voltage. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
