| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an illumination device not lowering control voltage of a voltage control circuit even when an input voltage is dropped, restraining generation of large current after the input voltage gets back to a normal voltage. <P>SOLUTION: The illumination device is composed of a light emitting element driving circuit 2 constituted by serially connecting a plurality of light emitting diodes LED1 to LEDn and driving elements T1 to Tn, a voltage control circuit 1 boosting input voltage of a power source 4, and impressing the boosted prescribed voltage on the light emitting diode driving circuit 2, and a current control circuit 3 controlling the driving current of the light emitting element driving circuit 2 in constant value by impressing a first prescribed voltage on the driving elements T1 to Tn when the input voltage is same with a set voltage or higher, and limiting the driving current by impressing a second voltage corresponding to the input voltage on the driving elements T1 to Tn when the input voltage becomes lower than the set voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
