| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a LED drive device for a vehicle, capable of ensuring the current amount supplied to an apparatus performing a more important function than LED by reducing the current amount supplied to the LED when a power supply voltage is lower than a predetermined voltage value. <P>SOLUTION: The LED drive device for a vehicle is provided with LEDs and switching devices connected to a power wiring in series; voltage measurement means of measuring a voltage value of a power supply; and control means of controlling a duty ratio of a driving signal input into the switching device, based on the voltage value of the power supply measured by the voltage measurement means and outputting the driving signal to the switching device. The control means, when the voltage value of the power supply is larger than a predetermined voltage value, controls the duty ratio of the driving signal so that the brightness of the LED is constant, and when the voltage value of the power supply is lower than the predetermined voltage value, controls the duty ratio of the driving signal so that the brightness of the LED lowers. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
