10W/20W High Power White LED

[DanPBP]

Hello Guys,

Thank you very much for your answers! I forgot to mention which LEDs I'm talking about. These are the ones:

http://cgi.ebay.com/1-PC-10W-WATT-ST...item27ada81b9d

http://cgi.ebay.com/20W-White-Led-10...item27ad5b8aec

I'm only going to use them for about 3 hours a week, so I don't need something expensive.

Thanks!

Daniel.

[DanPBP]

Hey Guys and Melanie,

Today, I got the 10W white LEDs I was talking about...



These things are too bright!!! And, also, too hot!!! The diameter is 22.5mm and they are huge!!!

I'll put some pictures soon, when I have the circuit for them (3S LiPo + heatsink + cooler) up and running...

Thanks!

Daniel.

[rsocor01]

These things are too bright!!! And, also, too hot!!!

Yes, they are bright. I bought a few 1.5W white power LEDs a few months ago for one of my projects and I was really surprised to see how bright they are.

They are also hot. You need to design your PCB board with some means to disipate the heat (heat sinks).

Robert

[DanPBP]

Hey Guys,

Which transistor or mosfet can I use to control (on/off/pwm) these LEDs?

They need 12v and 1A, if possible, I don't want to add a heatsink to the transistor.

Thanks!

Daniel.

[Byte_Butcher]

Hmmm... welll.... There's probably about a million devices that MIGHT be suitable.
What package styles are you willing to consider will narrow it somewhat. What's readily available to you might narrow it a lot more.

Look for an N-channel MOSFET that has a good low RDS(on) that's specified at a LOW gate voltage. (Vgs)
A PIC running on 5 volts may not put out much more than 4 volts on it's I/O pin, so it's important that you can turn the MOSFET on good and hard with a Vgs less than 4 volts.
It doesn't do any good to have a small RDS(on) if it takes 8 volts of gate drive to get it....

I use a lot of these but they are in an SOT223 package. They will handle over an amp easily if they are on a circuit board that has adequate pad area under the FET's
http://www.fairchildsemi.com/ds/FD/FDT439N.pdf

But you probably don't want SMD?
A TO-220 or similar package would easily dissipate enough heat for what you want without further heatsinking.


steve

[Ioannis]

Look for the BUK9575 from NXP. Logic driven MosFET.

http://www.nxp.com/documents/data_sh..._9675-100A.pdf

Ioannis

[alicesmile]

arrel produced the 1st version of the PID code to drive just one channel. I then compiled and ran it to see how it performed. Over the course of several evenings I managed to get the values tweaked enough to maintain a stable temperature that would drift no more than 0.5 a degree in the course of the evening.

Armed with the feedback, DT then went on to work on multiple channel PID loops, and after a few weeks of frantic PM's between him and Henrik came back with some further code for me to test and try. The result was that after some further tweaking at my end, we managed to have 4 independent channels all running at the same time and in the test rig, maintaining a constant temperature.