Thank you all for quick replay.
I am looking for driver for Luxeon K2 leds. Input minimum voltage is 5v 6Amp
which makes it
30 watt and each Luxeon LED takes about 3.5v 1.5Amp but 90% of it 3.0v and
1.0A . There are 8 output LEDs so to make it work I need to Boost
5V to 28v and must be constant current 1.5A output. I was originally
thinking to use LM3485 but it is Buck converter
It looks like I need Boost wide input range IC. Any Idea will appreciate.

Thank you again.

Andre




-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
Robert Young
Sent: Monday, June 16, 2008 2:44 PM
To: Microcontroller discussion list - Public.
Subject: RE: [EE] Buck vs Boost




> Subject: [EE] Buck vs Boost
> Date: Mon, 16 Jun 2008 14:30:55 -0700
> From: aabelian@mason-electric.com
> To: piclist@mit.edu
> 
> Hi to all,
> 
> I like to know what's the different between Buck and boost?
> Both of them uses inductor. Reading some info on google search I still
> do not get it? Any info will appreciate.
> 
> Thanks
> 
> Andre 

http://en.wikipedia.org/wiki/DC_to_DC_converter

In general and greatly simplified :
Buck drops voltage.
Boost increases voltage.
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