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power distribution for an application

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hi all !!
I'm currently working on a module which requires to be powered on by more than or equal to 5(may go up to 8 ) inputs of 12V,4A each.My requirement is that it should be powered on by one source at a time while rest of the sources remain silent.If input1 went off or switched off then it automatically switches to the second source .
Is that thing feasible?could you suggest me a circuit or any power distribution switch or any kind of multiplexer sort of stuff that meets my criteria.

would be obliged



Seems to me that you need to decide exactly what sort of relay or electronically controlled switch will be able to handle the current and voltage of each individual unit.
Maybe you could use a mosfet, or possibly a bipolar transistor.
The idea is that you should be able to use a standard logic gate ... maybe TTL .... to control the on and off status of each one. Then the problem resolves to just finding a counter or whatever other arrangement of gates will comply with your requirements.
... Sorry about not being specific .... getting a little late here .....


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How about just tying the five supplies through five diodes with the cathodes of the diodes tied to your common load. That way, the load is always on if at least one of the supplies is on. Its still on even if multiple supplies are on, although it will draw current from the supply with the highest voltage output. Schottky diodes have the lowest forward drop (~0.3V)
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