power led drivers circuits?

Discussion in 'The Projects Forum' started by gimon_1982, Aug 20, 2009.

  1. gimon_1982

    Thread Starter New Member

    Aug 20, 2009
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    can i ask you a questions?
    how can be produced small size power supply? i need small size power led driver circuit as DX-04350V and DX-MU38-5 like these models in link which is given below.

    http://www.diox.com.tr/led_suruculeri_01.asp

    if anyone helps me so i will be so glad.
    Anyone has circuit diagrams for like these product?
    i need 230 Vac input, 350ma constant current small size power led driver.I know there are many led driver ICs but how can be make like DX-04350V and DX-MU38-5 products.?They are small size and they can connect to electric network directly.
    Thanks for your kindness.
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    I don't read ?Turkish?, and the english side is under construction. If you take the time to think it out homebrewed power drivers are easy, and you can get power supplies pretty cheap.

    Define the job. How many LEDs? Color? Special effects? And work from there.

    Have you read this?

    LEDs, 555s, Flashers, and Light Chasers
     
  3. gimon_1982

    Thread Starter New Member

    Aug 20, 2009
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    Just one white power led. it can be so cheap but i want to know what kind of circuits they use. my led properties: 350ma ,3-4 Voltage rate, and 1 watt white power led. how can be make small size power supply as i gave in my links. i think they dont use transformers.
     
  4. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Take a look at the LM3407 led driver.

    Greetings,
    Bertus
     
  5. jj_alukkas

    Well-Known Member

    Jan 8, 2009
    751
    5
    Or drive it using a regulator like LM317 in constant current mode.
     
  6. bertus

    Administrator

    Apr 5, 2008
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    Hello jj,

    A LM317 as current source will have a very low efficiency.
    The switched LM3407 will have a much better rendement.

    Greetings,
    Bertus
     
  7. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    The 230VAC requirement is a bit touchy.
     
  8. gimon_1982

    Thread Starter New Member

    Aug 20, 2009
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    i understood all of your answers but i want to connect 230 Vac to input.and i will use this product for lighting so it will work long time.
     
  9. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    There are not many driver IC's for 230 VAC.
    The ones I found are for high power like street lights.( > 25 Watts).

    Greetings,
    Bertus
     
  10. Wendy

    Moderator

    Mar 24, 2008
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    Think wall wart, and go from there. It's safer in the long run.

    How many of these are you planning on making?
     
  11. jj_alukkas

    Well-Known Member

    Jan 8, 2009
    751
    5
    Bertus you are perfectly right. I just suggested an alternative as a last option in case he couldn't find the chip you suggested.

    This same topic has come on this forum in the last few weeks. Everone suggested him to get a cell phone smps charger or a wallwart as Bill suggested. It is the most cheap, efficient and worthy solution.
     
  12. gimon_1982

    Thread Starter New Member

    Aug 20, 2009
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    may be 100 may be 500 . is there any wall wart circuit s shematics? high AC voltage input, 3V-6V output voltage, 300-350ma output current. output power must be 1 Watt or 2 watt. and i want to learn how driver producer firms make small size power led driver circuits?
     
  13. jj_alukkas

    Well-Known Member

    Jan 8, 2009
    751
    5
    Why don't you try getting a simple cell phone charger? Then if it works well for you, you can buy more or try building one yourself. Chinese people make cheap drivers for ordinary LED's using a capacitor in series. But you can't do that with 1 W led's.
     
  14. gimon_1982

    Thread Starter New Member

    Aug 20, 2009
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    Is there any constant current cell phone power supply circuits. i mean current feedback . anyone has like these cell phone power supply? small size and can give between 250-320 ma current, between 3-6 Volt output voltage. do you know any information about power leds?i know that their resistance change by time so i need constant current feedbacl power supply.
     
  15. Wendy

    Moderator

    Mar 24, 2008
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    If you have a constant voltage power supply a simple resistor would suffice. But first you must have a power supply, be it a wall wart or phone charger (which is much the same thing). After you have a good source of power the rest is easy. Really easy.
     
  16. gimon_1982

    Thread Starter New Member

    Aug 20, 2009
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    ok i understood you. But why people produce led driver circuits? Led driver circuits have high price about 5-6 dollars for 1.4 watt power led driver. i cant understand that if it was so easy why people buy special led driver circuits? i cant solve this:).
     
  17. Wendy

    Moderator

    Mar 24, 2008
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    Because the majority of people don't do it yourself. Electronics intimidates a lot of people, and most just want to get it done. A few, like most on this site, want to understand electronics. It is one of those cases where understanding can save money, but most folks have better things to do.
     
  18. gimon_1982

    Thread Starter New Member

    Aug 20, 2009
    8
    0
    But there s a magic point that power leds have dinamical resistance. it means if they heat much so their resistance rise.i think constant voltaged power supply cant be usefull for power led project. power supply must have current feedback.
     
  19. Wendy

    Moderator

    Mar 24, 2008
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    OK, but first the power supply. It is the starting point for all else.
     
  20. jj_alukkas

    Well-Known Member

    Jan 8, 2009
    751
    5
    A 1 watt LED is no different than an ordinary LED except for the fact that it consumes more power and produces more light. The structure and basics are the same. 90% of the 20mA LED's on this planet run on power supplies which can produce atleast 300mA current and their current limited using resistors. If you have a powersupply, you can do it the easy way. The more closer the power supply is to the LED's forward voltage (Vf), the more efficient your circuit will be so it doesn't need to waste energy as heat either on regulators or resistors. But the supply must not be less than Vf of the LED.
    LED drivers are for people who desn't care how the world rotates, just it does thats it.
     
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