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Thread: Help in drive 92*Cree XRE P4 leds.

  1. #1

    Default Help in drive 92*Cree XRE P4 leds.

    Hi all
    My name is Murilo, im from Brazil and im trying to turn on at same time 92 Cree P4 leds.

    Im was thinking about using 5 or 6 Lm3404HV but i dont know if its the best option, can someone give me some tips? ^^
    In Lm3404Hv i was thinking in use a 73v x 6Ah supply to drive 3 rails with 18 leds and 2 rails with 19 leds, each one at 1A of current.

    Someone have a better way to do this array?

    http://img152.imageshack.us/my.php?i...sc09400qe9.jpg
    http://img143.imageshack.us/my.php?i...sc09391mq7.jpg


    Tks all
    Hugs
    Murilo

    PS: (sorry for my english )
    Last edited by Murilo; 04-03-2008 at 07:27 AM.

  2. #2

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Can you give us more info on the use?

  3. #3

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Quote Originally Posted by Mash View Post
    Can you give us more info on the use?

    Sure,

    Im making a little led blade, in this form:
    http://img521.imageshack.us/img521/91/dsc09431bw6.jpg

    But i dont know which is the best way to drive then, maybe someone have a better idea then my (using lm3404hv)

    the heatsink
    http://img527.imageshack.us/img527/4...sinkyq8.th.jpg

    the blade with glue on heatsink
    http://img262.imageshack.us/my.php?i...adefullcb5.jpg

    not necessary this wiring...
    http://img527.imageshack.us/my.php?i...edbladerk7.jpg


    can someone help me please? :$

  4. #4

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Are they all in series? Won't that be like 300V+ input? Thats pretty high.

  5. #5

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Quote Originally Posted by Murilo View Post
    Hi all
    My name is Murilo, im from Brazil and im trying to turn on at same time 92 Cree P4 leds.

    Im was thinking about using 5 or 6 Lm3404HV but i dont know if its the best option, can someone give me some tips? ^^
    In Lm3404Hv i was thinking in use a 73v x 6Ah supply to drive 3 rails with 18 leds and 2 rails with 19 leds, each one at 1A of current.

    Someone have a better way to do this array?

    http://img152.imageshack.us/my.php?i...sc09400qe9.jpg
    http://img143.imageshack.us/my.php?i...sc09391mq7.jpg


    Tks all
    Hugs
    Murilo

    PS: (sorry for my english )
    What is the supply range? You mention 73V. If that is a battery what is the full charge state and what is the fully discharged state voltage?

    You might be better off with a linear regulator for some of the strings and the odd remainder a LM3404HV for the balance.

    Another possibility if Vin doesn't vary too much is just a plain resistor.

    Wayne

  6. #6

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Quote Originally Posted by Shaocaholica View Post
    Are they all in series? Won't that be like 300V+ input? Thats pretty high.
    Not, on 5*lm3404hv im thinking in 3 lines with 18 leds in series and 2 lines with 19 leds in series, i will use exactly 92 leds, so maybe i need a 74v @6A suplly.


    Or can use 6*lm3404hv with 4 lines with 15 leds in series and 2 lines with 16 leds in series, in this configuration i need a ~65v @6/7A supply.


    I was thinking in use computer power suplly with mod for higher output, i think i easy get about 20v 8A(i have 5 ps in my hands :P), but the problem is the current of it.... i dont know how i can control it..

    A friend in China found the lm3404hv for ~8 USD, and just for tell i buy a 300w AT power suplly for less then 8 USD, so idk what i can use





    Someone can help me? has some better idea?

    Tks
    Murilo

  7. #7
    Enlightened
    Join Date
    Mar 2006
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    Brwinów/PL
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    67

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Quote Originally Posted by Murilo View Post

    Put off 2 LEDs, you got 90 pieces then.
    Make 30 x 3 in series (each "three" with a resistor) fed from appropriate SLA. It will eat about 30 amps .

    If you *must* use 92, the extra 2 can also be fed from the same SLA but with another resistor.

    Just my idea.

    -- M.

  8. #8

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Quote Originally Posted by Mel_PL View Post
    Put off 2 LEDs, you got 90 pieces then.
    Make 30 x 3 in series (each "three" with a resistor) fed from appropriate SLA. It will eat about 30 amps .

    If you *must* use 92, the extra 2 can also be fed from the same SLA but with another resistor.

    Just my idea.

    -- M.

    Tks for ur idea, and yes i need all 92

    From the power pc supply i can easy drain 13,8v@15A maybe 11,1v@15A too or try get 14,8 - 15v@10A, if i use to much resistors my final power will be too high i think but my fear is about the current on leds, that on the driver can be regullated to constant 1A thats why im think in lm3404.

  9. #9

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Someone plx???

  10. #10
    Flashaholic* Data's Avatar
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    Feb 2005
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    PA, USA
    Posts
    2,933

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Murilo

    Looks like a fun project.

    What does the bank of lights do? If you do not need to strictly regulate the light output then just direct drive the Cree XR-E emitters. They can take 2amps and still hang in there fine (see DB70 link below). If you design the power supply to within +-20% of one amp to each emitter that will be fine. The Cree emitter does not care about amps as much as heat. Just keep it cool. If you run the XR-E at around one amp and keep it cool, it will last for a long time.


    my DB70 thread



    Cheers
    Dave

  11. #11

    Default Re: Help in drive 92*Cree XRE P4 leds.

    Quote Originally Posted by Data View Post
    Murilo

    Looks like a fun project.

    What does the bank of lights do? If you do not need to strictly regulate the light output then just direct drive the Cree XR-E emitters. They can take 2amps and still hang in there fine (see DB70 link below). If you design the power supply to within +-20% of one amp to each emitter that will be fine. The Cree emitter does not care about amps as much as heat. Just keep it cool. If you run the XR-E at around one amp and keep it cool, it will last for a long time.


    my DB70 thread



    Cheers
    Dave
    Tks for showing ur great job in this bank, my 92 leds will be drive to take light trough one lcd display for a diy projector, so, like u say, so if i can keep it cool i can drive it to 1,2A , so i think i will try use 2 of that pc power supply in 15v in parallel with high current diodes in output to give about 15v @25A

    Do u have some other idea?

    Tks!
    Murilo
    Brazil

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