LED POWER SOURCE APPARATUS AND LED POWER CONTROLLING METHOD

摘要

PROBLEM TO BE SOLVED: To keep the lighting quantity of light in LED unchanged regardless of change of the number of the LED being lit in an LED head. SOLUTION: An LED power source controller part 102 is provided for the voltage control for correcting the voltage change due to the resistance between the power source and the LED head according to the current change to an LED head 103 comprising an LED array. The LED power controller part 102 comprises a current detecting part 106 for detecting the current change between a DC power source part 101 and the LED head, an output voltage controlling part 107 for outputting the voltage control value according to the output detected by the current detecting part based on the relationship between the current increase and the reduced voltage value per one LED lit in the LED array, and a regulator 105 for adjusting the power source voltage to the LED head according to the voltage control value. The voltage can be controlled also by predicting the voltage change based on the number of the LED emitting light expected by the image data.