How to connect 10x 10W Power LED?

I have 10x 10W LED, vf = 9V and fc=600mA.

I planned to conect them 2 in a row and 5 rows in parallel.

From this, i know that the overall row Vf = 18V and fc=600mA
overall current drawn from the source = 3A (min)

I plan to use 24V source to power this circuit, anyone can kindly advise me,

1. How I ensure the current into each row is constant at 600mA?
2. do I need voltage regulator or just a power resistor connect onto each row will do?

anyone pls kindly advise.. Thanks a million

PS: Happy new year to you all

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acidjc (author) 6 years ago
Thanks all for your kind advise, I planning to use this


any advise will this good enough for my 2x 10W running at 600mA , 24V DC supply

I computer to use a 2ohm 1W resistor + a LM317, as according to the instruction stated in the link above.
frollard6 years ago
Don't just use a passive resistor for 10 watts of power - you're burning off a quarter of the power to get down from 24 to 18, and it will vary with temperature. Resistor = bad!

Use a constant CURRENT source that self-adjusts to allow for temperature and voltage variation.


Step 6/7 has several...they advise (as always) find a power source that CLOSELY MATCHES your sum led forward voltages! Otherwise, you're just wasting power.
TO be honest, though clever, the circuits in there don't address the dissipation issues. For efficiency, and to be true switch mode, you need to use an inductor in the circuit. I have one or two designs I am going to put up on here sometime.
tis true -- they still rely on good source choice to reduce waste -- but they do provide protection from the perils of over-current -- the cheapest win-lose scenario that is easy to pull off. True win-win (as described in the ible) requires smart switch-mode electronics, and more skill than most people have.
Granted. Its not actually hard, using National's Simple Switchers to make a constant current drive - I've done it myself. Linear do a really nice driver for 3V LEDs, it needs their chip, and an inductor !

I really can't wait to see your incarnation! I've been hankerin for a smps that is accessible to 'us' :)
aelias366 years ago
Google is your friend. I've already used it for you, though:


You only need LEDs and resistors.
not for ten watt leds -- it gets too complex on these huge ones: the logistics of small leds make it feasable to just use a resistor -- on big leds, you're asking for trouble using a big resistor.
Oh, sorry! I misread. I thought it was 10 *mW* . My bad!
yeah, easy mistake - its what I thought at first.