| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an LED lighting device and a luminaire therewith which reduce a switching loss during normal operation. <P>SOLUTION: The LED lighting device includes: a step-up section 2 that has a switching element Q1 and steps up and outputs an output voltage from a DC power supply 9 when the switching element Q1 is switched over; a step-down section 3 that has switching elements Q2, Q3, which constitute a series circuit connected between output ends of the step-up section 2, and steps down and applies the output voltage of the step-up section 2 to a light source unit 8 when the switching element Q2 connected on a high voltage side is switch-controlled while the switching element Q3 connected on a low voltage side is in a turned-off state; and a control section for switch-controlling the switching elements Q1, Q2, Q3. A drain-source parasitic capacity Cds2 of the switching element Q2 is made larger than a drain-source parasitic capacity Cds3 of the switching element Q3. <P>COPYRIGHT: (C)2012,JPO&INPIT |
