| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To apply light stably, and to extend a lifetime by reducing stress to an LED. <P>SOLUTION: An LED drive detects voltage V3 in a resistor 42 and voltage V4 in a resistor 43 by a drive section 5. Then, a DC voltage V1 and a DC current I1 of a DC power supply 40 are converted to a drive voltage V2 and a drive current I2 so that the product of the drive voltage V2 and the drive current I2 supplied to an LED unit 3 in which a plurality of LEDs 31, 31, 31 are connected in series becomes constant, based on the voltages V3, V4. Then, the drive voltage V2 and the drive current I2 are supplied to the LED unit 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
