Question about modification

[**DONOTDELETE**]

What is a DC/DC converter?

Which is the function of the DC/DC converter in the LS modifications?

Thanks for you response....

 

[Saaby]

LEDs are efficient, even Luxeon Stars, but that doesn't change the fact that they're diodes. Diodes are gates of sort, but they won't open unless enough electrons have backed up, it takes a certain ammount of energy to get the juices flowing, for a LS to be bright it takes a little more voltage than you can get out of 2 batteries...

AC/DC turns AC/DC power...
DC/DC turns DC into DC with more voltage but less current...the total ammount of "power" if you will, is the same with or without the DC/DC.

 

[lux0]

A DC/DC convertor converts DC, first to AC (or pulsating DC), steps the voltage up or down, then rectifies and filters it back to DC.

 

[Starlight]

DC/DC converter advantages; 1. Provides the higher voltages required by LED's with a lower voltage battery source 2. Gives a "flatter" output (light doesn't dim as much when batteries run down and allows you to get more useable light from the batteries), disadvantage; inefficiency of circuits waste about 10% of power available from battery

 

[remuen]

Although the page is not yet finished you will get some more information about DC-DC Converters

 

[MrAl]

Originally posted by superbright10:
What is a DC/DC converter?
Which is the function of the DC/DC converter in the LS modifications?

Thanks for you response....

<font size="2" face="Verdana, Arial">Hello,

A DC/DC converter converts one voltage level to
another voltage level, either higher or lower.

In the case of the LS, the dc/dc converter
takes a lower input like 2.4 volts and boosts
it up to 3.3 volts or so. Without the dc/dc
converter, you couldnt drive the LS with
only 2 batteries, but would require at least
3 batteries. The dc/dc converter thus makes it
possible to drive an LS with only one or two
alkaline, NiCd, or NiMH cells. The cost for
this luxury is usually about 15 to 25 percent
of the capacity of the cell(s) as this is wasted
in the converter circuit.

Good luck with your LED circuits,
Al

 

[Quickbeam]

Point of correction: you can drive an Luxeon Star (LS) on only 2 batteries - I have 2 mods that do just that.

The DC/DC converter boosts the voltage (at the expense of some amperage) so that it drives the LS brighter than would normally be possible with 2 cells.

 

[MrAl]

Originally posted by Quickbeam:
Point of correction: you can drive an Luxeon Star (LS) on only 2 batteries - I have 2 mods that do just that.

The DC/DC converter boosts the voltage (at the expense of some amperage) so that it drives the LS brighter than would normally be possible with 2 cells.

<font size="2" face="Verdana, Arial">Yes, but you cant get much brightness, which
means you need a dc/dc converter for most apps.

--Al

 

[Quickbeam]

MrAl -

True. You don't get brightness levels that even come close to "pushing" the Luxeon Star at all, however the Rayovac Adventurelite headlamp mod (2-AA) puts out as much light as a Lightwave Illuminator 4-LED headlamp (3-AA), but with 1 less battery. As a result the light-output-to-weight ratio is very nice (especially where weight is important, such as a headlamp). So here we see a very "passable" application of an underdriven Luxeon Star.

[EDIT: actually I just tested the lights with my light meter again - the lightwave puts out about 50 lux while the LS mod headlamp puts out 100 lux - DOUBLE the output on one less battery - pretty impressive for being underdriven!]

OTOH, the Lambda Ill Pill Minimag mod, with a Luxeon Star, the same 2 batteries (2-AA), and a DC/DC converter easily matches or exceeds the output of a Lightwave 4000 - a 10 LED light that runs on 3-D batteries. So the DC/DC converters can really boost output.

(Homer voice) Mmmmmmmmm... Lumens...

 

[jeff1500]

Originally posted by remuen:
Although the page is not yet finished you will get some more information about DC-DC Converters

<font size="2" face="Verdana, Arial">I looked at your web page. It's coming along nicely.