| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a structure causing no breakage of an LED even if a common-mode noise voltage ( noise voltage to ground) is superimposed on an ac power source AC to which the power supply unit 1 is connected, in a separately set up power supply type LED lighting device having an LED unit 2 and a power supply unit 1 as separately set up units. <P>SOLUTION: In this LED lighting device, a DC current is supplied from the power supply unit 1 containing a rectifier circuit DB and a DC-DC converter circuit 5 in a metal case 6 to the LED unit 2 through a pair of power supply lines 3a and 3b, a ground noise voltage bypass capacitor 5C connecting a secondary side ground G2 of the DC-DC converter circuit 5 to the metal case 6 is provided, and an earth line 7 connecting the metal case 6 to the conductive part 4 of the LED unit 2 is provided. The capacitance of the capacitor C5 is set larger than combined floating capacitance Cy between each LED and the conductive part 4 of the LED unit 2. The conductive part 4 of the LED unit 2 is used as an aluminum heat sink also serving as a casing. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
