| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an LED drive device that can stabilize LED luminance even when using an unstable supply voltage as from a battery, and can share a printed board even if the types of LEDs and the numbers of those used concurrently vary. <P>SOLUTION: A plurality of drive circuits 30 are formed on the single printed board 10. The drive circuits 30 have the same configuration and are connected to a common power terminal 40. An LED 50 is connected to the plurality of drive circuits 30 outside the printed board 10. A supply voltage Vb at the power terminal 40 is detected with voltage dividing resistors 60 and 61, and a microcomputer 20 changes the number of drive circuits 30 used for energization from the power terminal 40 to the LED 50 according to the supply voltage Vb at the power terminal 40. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
