I am designing two boost converters ,one 3.3v to 5V and the other 3.3v to 12v. (2A)
I have already finalised my 5V design how ever for the 12v one i have a design (credits to 'Bordodynov') which is in slighty different layout to my 5v one.
I need some advice to make the 12v one into the same layout of 5v (which makes things easire while making the PCB).

I have attached the schematics below:

3.3-5V:




3.3-12V:

 

Why can't you just use the 5V design and increase R3 to give a higher voltage out?

 

Why can't you just use the 5V design and increase R3 to give a higher voltage out?

I have already tried that , in that case i cant get near enough current out!

 

I have already tried that , in that case i cant get near enough current out!

Then change the inductor and use a Slave mosfet, as per the datasheet.

 

Is C3 in the 5 volt version really 47 microfarads? If it is, it will make the dynamic performance absolutely dismal.

How much current? What are you using for an inductor?

The way those schematics are drawn the circuit is barely recognizable as a boost converter.

 

You may be able to get away with just buying one of these...
https://www.ebay.com.au/p/100w-DC-3...m=232323026259&_trksid=p2047675.c100010.m2109
From the printed specs, it might just scrape in for the 12V 2A.
But if you are going to design them yourself, that is a good project. I would recommend a bit of over design to make them a bit more reliable.