Competition for micro-puck?

[tonyb]

I was wondering if anyone would be interested in a Luxeon driver board that would run a 1 Watt or 5 Watt with a adjuster pot on the board to allow for current adjustment or an external pot to allow for user adjustment/ dimmability. What are your thoughts I'm open for suggestions/ comments. Thanks.

 

[Rothrandir]

who wouldn't want one?!

what kind of power would it require?

 

[tonyb]

It would run on 3 volts for 1 Watt and 6 volts for a 5 Watt.

 

[zmoz]

That would be great...especially if it was competitively priced with the micropuck. /ubbthreads/images/graemlins/grin.gif What I would really love is something like whatever is in the base of an everled. Give it almost any voltage and get perfect light...

 

[tonyb]

I dont think the everled works that way, the voltage has to be within a certain range and the ouput of the led still fluctuates, correct me if I am wrong. The everled uses a buck-boost converter, I'm engineering a step-up converter so the input voltage is lower than the output voltage, maybe someone else would like to take on that challenge of making a buck-boost converter.

 

[Jonathan]

I have a circuit that does what you describe. I use the LT1618 as a boost converter (using the reference design from the datasheet), with the adjust pin brought out. If I add a three terminal regulator (to get a fixed low voltage) and run a pot from the regulator to ground with the wiper connected to ADJ, then I get nice variable output.

I don't know how happy the 1618 would be at the currents needed for a 5W, but with 6V in it _should_ be happy. I have run 1W LS leds from this circuit using a pair of AA cells.

-Jon

 

[tvodrd]

tonyb,

Second sources would be much appreciated. How about as small as possible, circular form factor /ubbthreads/images/graemlins/grin.gif .

Larry

 

[PhotonBoy]

Would it work as low as 2.4 volts? i.e. for NiMH cells.

 

[tonyb]

Roger that tvodrd as small as possible and round form factor I know what your thinking he-he. I should have said 2 cell for 1 Watt and 4 cell for 5 Watt. Yes it will work down to 2 volt for two cells and 4 volt for four cells (NiMh).

 

[shiftd]

great. Is this going to be current regulated or voltage regulated? How hard this going to drive the luxeons?

 

[tonyb]

Current regulated mode and at least 100mA or more past luxeons ratings.

 

[shiftd]

Could it be at least as small as the puck? What is the price range? I think it should be at least the same price if not cheaper than the puck, except of course, it can do better, right?

 

[Rothrandir]

100ma or more is good...specifically the or more /ubbthreads/images/graemlins/grin.gif

 

[paulr]

I think "as small as possible" doesn't mix with "5W Luxeon" because of heat issues. You need two separate converters. Yes, please make one for tvodrd's CR2 light. It's fine if the current only goes up to 300 mA or so, I'd say.

I'd also like to be able to get a converter that can run a Nichia LED at 30 mA or so on 1 volt, like an Arc AAA converter, or better yet two or three such LED's. It would be great for making a mini-headlamp with one AA or AAA, for modifying other 1-cell keychain lights, etc.

 

[Lucien]

[ QUOTE ]
tonyb said:
I dont think the everled works that way, the voltage has to be within a certain range and the ouput of the led still fluctuates, correct me if I am wrong. The everled uses a buck-boost converter, I'm engineering a step-up converter so the input voltage is lower than the output voltage, maybe someone else would like to take on that challenge of making a buck-boost converter.

[/ QUOTE ]

Actually, on that note, Linear Tech recently released the LTC3440, a proper buck-boost converter with very nice (paper) efficiency figures. Only problem is it regulates on output voltage, and needs a fair amount of control theory understanding to work with.

I doubt I could pull it off, and I'm busy with another circuit at the moment, but if anyone else wants to try..... /ubbthreads/images/graemlins/wink.gif

Back to the original topic:
An adjustable 5W driver sounds interesting, I would imagine it would be useful in situations where runnning a 5W at full choke isn't desirable, or on the fly adjustment of intensity would be very useful.

I don't quite get what you mean by a pot on the board + an external pot though...

 

[tonyb]

Re: Competition for micro-puck? *DELETED*

Post deleted by tonyb

 

[Lucien]

[ QUOTE ]
tonyb said:
Not weed, and not something you cook with! A variable Potentiometer.

[/ QUOTE ]


Yes, that part I understand /ubbthreads/images/graemlins/yellowlaugh.gif

What I mean is why one inside and one outside? Wouldn't just one pot suffice?

 

[shiftd]

I think it is either inside or outside, not both.

 

[tonyb]

Hey it was late! Man what the hell was I trying to say! Well shiftd figured it out, are you a social worker, the reason I ask is because you could figure out my rant.

 

[Lucien]

Whoops, misread the first post /ubbthreads/images/graemlins/blush.gif My bad.

In that case I guess an external pot would be good, except for waterproofing issues.

[ QUOTE ]
tonyb said:
... are you a social worker, the reason I ask is because you could figure out my rant.

[/ QUOTE ]

Me or shiftd? Well I'm not anyway...