Help for convert 12v 3A DC to 5v 3A DC!

[rozeh]

Hi everybody
I have a charger that it give me 12v 3A DC output. now I want to change it untill give me 5v 3A DC but when see to it, it mix up me. look at it:











in below picture, you can see to IC that I determinated by number 1 and 2.
the number 1 IC is smk0760
and the number 2 is mbrf20100ct


in your opinion, How can I do it?

[mariush]

There are some resistors and capacitors on the back near the optical isolator. By adjusting those, you can make the power supply change the output voltage slightly.
However, it don't think it would be safe to lower the voltage to 5v, it's a bit of a stretch. It would probably be safe to do about 9-14v.

smk0760 is a simple mosfet, mbrf20100ct is a common cathode schottky power rectifier 20a maximum, 100v maximum (a bit oversized for this adapter but it's a good thing). Nothing you can adjust.

[Riotpack]

You would have to change the number of turns on the secondary of the transformer AND modify the feedback loop to do it properly. Would be easier to add a small high frequency buck converter to the output.

[rozeh]

Thanks mariush and Riotpack
What's your opinion about LM2596T-ADJ 3A? for regulate the voltage in output of the power supply?