power supply adpter(AC to DC) selection

[jigar.patel]

Hello All,
I don't have 5V, 5A power supply adapter (AC to DC ).
I have 12V, 3A power supply adapter.

my current requirement is 5A at 5V.

So, can (12V,3A) adapter replace (5V,5A) adapter?
because 12V power supply adapter has only 3A current capability & i require 5A current & 5V.

this adapter will be used to source the power to step down DC DC converter.

so can i use (12V,3A) power supply adapter instead of (5V,5A) adapter?

 

[nitishn5]

If you are using a switched type DCDC converter to convert 12V to 5V you can theoretically get 5V at 5A.

Max Power input = 12Vx3A = 36W.
Max Power output = 5Vx5A = 25W.

You cannot use a linear converter since the 12V adaptor cannot handle more than 3A.

 

[tpetar]

You can get both 5V and 12V from PC PSU on higher currents. Search for small PC Micro PSU, its around 100W and very small.

 

[jigar.patel]

Thanks to all for helping me to choose right adapter for my 12V to 5V step down DC DC converter.
I will use 12V, 3A (AC to DC) power supply adapter for (12V to 5V,5A) step down DC DC converter.

Once again thanks to All.