minature transformers wanted

I have a small project that needs both 5vdc and 12vdc.
I have a dual voltage power supply but it is way to big to fit in the box.
I can get a 5vdc usb charger that is about 1 inch square easy enough,
but finding a 12vdc one about the same size is not so easy.

So, just build a little one perhaps?
Finding a very small transformers for a dollar or two
with a 120vac input and outputs of about 7vac and 15vac is proving not to be so easy either.
Yes, there are deals out there, but will I be able to get another one 6 months from now and
another one a year from now.

Anyone know of any?
For lack of a better idea at this time,
miniature transformers wanted.

A 5VDC USB power supply probably makes more power than you need. I would use a PWM IC to boost the 5V to 12V. In my case I would build it but here is one built.
Boost Supply $6 (that's 3 supplies for $6)

Here is another one. Have not looked at it. link

Or a very different way.
Get a 120Vac to 12Vdc supply and then add a small 12V to 5V buck power supply. (looks much like the above supply, but works differently)

You can get leads, a usb connector one end with a 5v to 12v inverter inside, and a dc barrel jack at t'other, a little doctoring would give you a 12v and a 5v o/p.

I'd go with the 12V wall wart and 5V regulator. What current is required?

Mike.

Thanks for the replies.

Pommie said:

I'd go with the 12V wall wart and 5V regulator. What current is required?

Mike.

Click to expand...

Not much current is needed. At present, I think I'd go your way. Thanks, Mike.

Look at a Meanwell IRM-03 12V
That's a tiny encapsulated PSU that gives 12V at up to 3W from AC mains (world standard).

Add either a switching or linear 5V regulator and you have both supplies.

And they are cheap! https://uk.farnell.com/mean-well/irm-03-12/power-supply-ac-dc-12v-0-25a/dp/2815483

rjenkinsgb said:

Look at a Meanwell IRM-03 12V
That's a tiny encapsulated PSU that gives 12V at up to 3W from AC mains (world standard).

Add either a switching or linear 5V regulator and you have both supplies.

And they are cheap! https://uk.farnell.com/mean-well/irm-03-12/power-supply-ac-dc-12v-0-25a/dp/2815483

Click to expand...

Thanks. I like this idea. Meanwell also makes a 5vdc version.
Thinking I can use one of each and just connect the grounds together.
Does that seem workable?

jack0987 said:

Thanks. I like this idea. Meanwell also makes a 5vdc version.
Thinking I can use one of each and just connect the grounds together.
Does that seem workable?

Click to expand...

Yes, certainly - that would work fine.
The only reason for suggesting a 5V regulator with the 12V one was to save cost and space, if the power requirements were low enough.

rjenkinsgb said:

Yes, certainly - that would work fine.
The only reason for suggesting a 5V regulator with the 12V one was to save cost and space, if the power requirements were low enough.

Click to expand...

These are working great for me. Found out, they also make a 3.3vdc version which will work even better.
They make other voltages as well.