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Topic: Smaller Darlington array replacement (Read 655 times) previous topic - next topic

jfenwick

I'm looking to control some LEDs that could be between 1W and 3W.
I've been using the ULN2803A but it's kind of big, I only need 3 channels.
ULN2001 is slightly smaller but not by much.
What would be a good replacement?

CrossRoads

3 transistors with a base current limiting resistor for each.
At 5V, 3W = 600mA current flow.
N-Channel Logic Level MOSFET with low Rds would be best choice.
http://www.digikey.com/product-detail/en/NTD5867NL-1G/NTD5867NL-1GOS-ND/2401422
with 10K resistor from Gate to Gnd to keep it turned off while Arduino resets, and 180 ohm resistor from Arduino to Gate to limit Arduino drive current to ~25mA.

3W, you would have smoked the ULN2803 eventually.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

dc42

Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

jfenwick

Thanks!
What about with a 1W LED?
Would a ULN2803A be able to handle that?

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