tmmlrd:
I have to drive some high power LEDs (using TIP122 darlingtons), for a total current around 2 A on 12 V input. I'm wandering if I can drain this current from the V_in and GND pins of the Arduino Uno board, just connecting a 12 V supply to the Arduino board and using it to power both board and loads, or if there is a (lower than 2 A) current limitation on V_in. In the former case I presume I have to "duplicate" the power supply connection and provide current directly from supplier to loads, without using V_in pin...
Hope my question is clear enough.
Thank you very much for help.P.S. There was a similar question here http://arduino.cc/forum/index.php/topic,16348.0.html but I don't think the answer given there is right since there should not be any regulator between supply and V_in on Arduino board. However, there is between supply and +5V (this was the answer) but that's a different story... My concern is mainly about burning some traces on the PCB with a current as high as 2 A or so.
The problem with drawing 2 amps or more from the Vin pin is there is a series polarity protection diode wired between the external power connector's positive terminal to the Vin and input to the +5vdc regulator. This is a nominal rated 1 amp forward current diode, you might get away with drawing 2 amps through it but it would be exceeding it's rating, so probably not a good idea.
Lefty