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Forum Index : Electronics : Diode ORing

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ryanm
Senior Member

Joined: 25/09/2015
Location: Australia
Posts: 203

Posted: 01:01am 24 Feb 2017

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Hi Guys,

Wondering if anyone on here might be able to give me a few pointers on diode ORing power supplies, in this case swapping from a wall plug unit to backup alkaline cells. Bit under the hammer so if someone relies I'll get you some details on the project.

Cheers.

davef
Guru

Joined: 14/05/2006
Location: New Zealand
Posts: 499

Posted: 08:01pm 24 Feb 2017

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I assume you know how to connect the diodes in series with each supply to a common load terminal.

You will get a voltage drop so if you want to keep that around 0.3V then you will need to use Schottky diodes. Also consider the amount of current the diodes can handle and the resultant IR drop. You may need heatsinks.

ryanm
Senior Member

Joined: 25/09/2015
Location: Australia
Posts: 203

Posted: 08:07pm 24 Feb 2017

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Thanks for the help Dave.

Found a nice (but a bit pricey) chip from Linear that does it with a fet.

http://www.linear.com/product/LTC4412

I'm only making a handful so I'll just get some of those.

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