Drawing that much current effectively mutes the 47uF capacitor.
It sounds like you want to drive a high current load, motor solenoid etc.
Driving such loads will likely cause problems with the controller as dips in Vin will effect the Arduino.
If you need external high current capability use 2 or more power supplies with common grounds.
I want to use a sim908 (gps/gsm modem). It can works with 3.3v and it has peaks of 2.5A (short duration peak) when it transmits data.
So I will use a DC/DC converter from 12v to 3.3v as power supply for the sim908. I want to use Vin pin as source of DC/DC because I want to use a proto shield. So I will solder the sim908 and dc/dc converter on the proto shield. I could also use a 2200uF capacitor for the peaks of current.
I could connect the powerjack directly to the dc/dc converter but i don't want to solder cables on the jack, I want a "clean" circuit.
But i think that I will connect the powerjack directly to my dc/dc converter.
The other thing to consider is that the copper traces on the pcb between the power
jack and the Vin pin, and also various ground pins, may not even be able to handle
3A without burning. Who knows? Probably best to just route power to the GSM module
externally.
oric_dan:
The other thing to consider is that the copper traces on the pcb between the power
jack and the Vin pin, and also various ground pins, may not even be able to handle
3A without burning. Who knows? Probably best to just route power to the GSM module
externally.
Yes, I considered that. But the peaks are very very short duration (normal consumption is about 250mA)...
I have already use the sim908 in another project, the pcb tracks were very thin but the pcb has not burned (I used it for a long time). In that project I used some capacitors for a total of about 4700uF (my power supply was be able to give only 2A max).
I will try to power the gms module through the Vin pin (with also a "big" capacitor) because I'm curious now. I will let you know if I will burn Arduino Due
I want to understand the small circuit before the regulator which includes diode D1 and the ferrite bead.
Comparing the Due to the Uno, D1 is now parallel rather than in series, so current pull should not depend on the diode (correct me if I am wrong). Rather, between VIN and the Power Jack is the ferrite bead rated at 3A.
Going back to D1, I see that if there is a reverse voltage VIN and GND become shorted which is scary to me, but I guess it saves the electronics - but may destroy your power supply.
Now to summarize, assuming that power is wired correctly. VIN pin should be able to source 3A.
I am developing my on motor driver board so I am trying to understand if developing external power is necessary or I can just use VIN.
If there is anything I said wrong, please correct me.