Selective DC power supply

[oy1987]

Hello,

I am looking for a module that selects automatically between the main power supply (DC supplier), and the backup supply (battery) when my main source is off.
I tried searching for mini power converters or BMS but didn't find what i needed.
If i had more time I would design one myself, but I'm affraid i don't have the time needed (maybe in the future).

Thank you,
Or

 

[E-design]

What about a simple relay that when the power drops away will switch through the battery?

 

[oy1987]

That's an option.
I thought of this solution, but I thought that a relay may not be quick enough to switch and I need an immediate response.
If you know of a good relay that does that especially for FPGA/MCU boards, I open for suggestions.

Thanks,
Or

 

[E-design]

Depending on the power consumption of your circuit the hold-up time of capacitors on the input supply side of the circuit may be long enough for the relay to change states.

 

[oy1987]

That's something I wasn't thinking of. Since it is easy to try I will test it.
In the meanwhile I found this: https://goo.gl/zedJzO
It's something called a PicoUPS, and it's almost what I am looking for (I need 5V power supply and I am trying to avoid putting a voltage regulator).
Thanks,
Or

 

[chuckey]

How about using ORing diodes?
Frank

 

[Tihomir Grozev]

You can use any schottky diode instead of this thing for 35bucks
Also can put a resistor over the diode to charge the battery, when main is available.