| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a light emitting element driving device which can always output a minimum voltage satisfying driving qualifications and whose light emission efficiency is high and power dissipation is low, and to provide a portable unit using it. <P>SOLUTION: In an LED driving device 10, LEDs 20-1 to 20-n of different driving voltages required for light emission are connected parallel and it drives one or a plurality of LEDs. It has driving circuits 13-1 to 13-n which performs current drive for a corresponding LED with luminance based on a set point and power supply circuits 14, 15 which distinguish a driving voltage value required for highest light emission of one or a plurality of LEDs which are subjected to light emission driving based on driving condition (for example, a terminal voltage of a current source) of each driving circuit, and supply the driving voltage of at least the distinguished value to a plurality of LEDs parallel. <P>COPYRIGHT: (C)2004,JPO</p> |
