LIGHTING DEVICE, ILLUMINATING FIXTURE, METHOD OF DESIGNING LIGHTING DEVICE, AND METHOD OF MANUFACTURING LIGHTING DEVICE

摘要

PROBLEM TO BE SOLVED: To stabilize an optical output with a simple configuration, in a lighting device for a solid light-emitting element using a DC/DC converter.SOLUTION: A lighting device 1 connected with a DC power supply 2 to supply current to a solid light-emitting element (an LED 3) whose forward voltage is in a range of Vfmin or more and Vfmax or less, comprises a DC/DC converter (a buck converter BC1) and a controller CNTL. The DC/DC converter has a switching element SW1. The controller CNTL controls and turns off the switching element 1 by peak current control, and in a case where the forward voltage of the solid light-emitting element connected to the lighting device 1 is Vfmax, the DC/DC converter controls and turns on the switching element SW1 at such a fixed cycle that a BCM operation is performed.