Pages: [1]   Go Down
Author Topic: Smaller Darlington array replacement  (Read 517 times)
0 Members and 1 Guest are viewing this topic.
0
Offline Offline
Jr. Member
**
Karma: 0
Posts: 65
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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?
Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 524
Posts: 26466
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

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.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

United Kingdom
Offline Offline
Tesla Member
***
Karma: 224
Posts: 6593
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

If you want to go smaller still, how about http://uk.farnell.com/taiwan-semiconductor/tsm2314cx/mosfet-n-ch-20v-4-9a-sot23/dp/1864589.
Logged

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.

0
Offline Offline
Jr. Member
**
Karma: 0
Posts: 65
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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

Pages: [1]   Go Up
Jump to: