| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To realize stable light control in extremely low luminance, in a backlight driving device using a switching current source generating a high current. <P>SOLUTION: A current output from a switching current source 3 becomes the fixed minimum Imin when luminance is not more than prescribed low luminance, a fixed-cycle pulse width current Ib corresponding to a luminance setting signal Vs flows in a light emitting element 4 by a switching means 6, and a dummy current Id having a phase opposite to the pulse width current flows in a constant current load 7. Since the duty ratio of the pulse width current Ib falls as the luminance setting voltage (s) is lowered, light can be stably controlled in extremely low luminance. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
