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I have two very simple assembled voltage regulators using AMS 1117-5. They are a 5 VDC output @ 1 Amp (I have seen some paperwork state 5 VDC @ 0.8 Amp). The current draw of the Raspberry Pi with attached load is 0.65 Amps.

I need to keep things small and simple so I would like to connect the output of each regulator in parallel. The voltage is more important than the current draw. I cannot use OR Diodes or anything that would drop the voltage.

Do you think there would be any issues in just hooking them in parallel?

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  • \$\begingroup\$ a) Why parallel when your load is less than the capability of a single regulator. b) One regulator will likely take the majority of the load anyway, though you might get some droop regulation. c) It's asking for trouble because even though it MIGHT work you may also have stability issues since they are not designed to work in parallel. \$\endgroup\$ Commented Jan 18, 2017 at 0:27
  • \$\begingroup\$ With the old classic LM78xx regulators, it was possible to slightliy increase the output voltage by adding one or two diodes between the ground pin and the ground. Maybe this way you can use the OR diodes to parallel the regulators. I've not tested it with the 1117, though... \$\endgroup\$ Commented Jan 18, 2017 at 20:38

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No two regulators are alike and have small offsets from the nominal voltage, this can cause one regulator to take more of the load than the other. The easiest way is to put a small resistor to limit some of the current between the regulators if you don't have too much of a load. See this article for more info. There are other ways to balance the input if they have a feedback pin, but in your application resistors should be fine.

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