NNTP-Posting-Date: Sun, 24 Nov 2002 09:52:17 -0600
From: "James Jackson"
Subject: Re: luxeon star leds
Date: Sun, 24 Nov 2002 09:52:20 -0600
X-Newsreader: Microsoft Outlook Express 6.00.2600.0000
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
Just to add a bit of confusion to the mix...
The company I work for is using these Luxeon Star LEDs.
I helped design several PC Boards to mount them on.
I have, so far, designed 4x LED PCBs, 5x LED PCBs, 10x LED PCBs and 12x LED
The LEDs do get a tad warmish - but seem to do okay.
If anyone is interested in obtaining these PCBs, or details on them, I may
be able to put you in touch with a fella who would be intrested in talking
BTW: There is a class held by the folks at Luxeon - that may be helpful to
some. I know that the fella at the company went to it, and came away with a
notebook full of information, and a more clear idea of how these LEDs work.
"R. Lewis" wrote in message
> I seem to have a problem with the luxeon star - or its data.
> Luxeon quote a tempco of forward voltage of -2mV/degC and a theta
> to board) of 17 degC/watt.
> However, with a constant current source, if I power up a device (in free
> air- no additional heatsinking) and measure the forward voltage (takes
> 30mS for the first reading) and subsequently monitor the forward voltage
> the temp on the aluminium pcb I get a far greater temp rise on the pcb
> the temp rise of the junction.
> How is this so -- or what am I doing wrong.
> How can I otherwise determine junction temp?