LM5050-1: OR'ing two different level supplies

Thomas Phelps

Part Number: LM5050-1

Hi,

I'm looking to use two LM5050-1 Highside OR-ing FET controller in a new design to combine a primary and redundant supply and I have a question I hope you can help with.

The primary supply is 48V and the redundant is 28V, in normal operation both are present. It is OK to source current from either of these in normal operation. If the 48V fails the 28V will be required to source all of the current. Is it acceptable to OR two different voltage rails like this using the LM5050?

I think this kind of application is acceptable with a standard diode and can't see any issues with the LM5050 but would like to verify if possible with you.

Kind Regards,

Tom

over 7 years ago

0 Karikalan Selvaraj over 7 years ago

TI__Genius 16305 points

Hi

LM5050-1 can be used to OR 48V and 28V rails with 48V as primary source.
As long as the minimum operating voltage of 48V rail, does not fall below 28V, it should not be an isssue.

Regards,
Kari.

0 Thomas Phelps over 7 years ago in reply to Karikalan Selvaraj

Prodigy 40 points

Thanks for the answer Kari, much appreciated.

Out of interests is the worry over the 48V falling lower then the 28V due to current share/keeping the 48V as a primary? Just trying to understand fully why the 48V falling lower may be an issue?

Thanks,

Tom

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LM5050-1: OR'ing two different level supplies