is it possible to use a low voltage controller at higher voltage?

i want to make a isolated switching power supply intended to drop and convert 220VAC to 12VDC, but the only available controllers in my area can only handle 100VDC at maximum. is there a way where i can use those switching controllers at 220VAC?

Comments

[steveastrouk]

Not readily. The whole front end is designed for 100V operation.

MOST modern switchers though are designed to be universal input.

[codestroy7]

Not readily? Is there some way to do it? Like, having a first stage to provide proper voltage for the controller?

[steveastrouk]

How many VA ?

Where are you in the world anyway ?

[codestroy7]

where in the world? philippines
VA? i don't know exactly but i need 12V 1A.

[steveastrouk]

Get an ordinary transformer - something like 20VA will do, with a tapped or split primary. FORGET the secondary, but you need a transformer of at least 15VA.

Connect the supply input to the 230 V pins, connect the 110 V PSU from the 110 V pin and the neutral connection.

Here's a sketch

[codestroy7]

Using a 60Hz transformer might drastically increase the size of the project. Can i use a frequency transformer? i was thinking of applying an isolation after the controller where frequency is high.

[steveastrouk]

Are you sure you can't get universal input supplies ?

I wouldn't mess with the internals of a switcher.

[codestroy7]

i really don't have the resources for universal input.

[steveastrouk]

You're stuck then. Though, like I said, I haven't seen anything BUT univeral inputs for years.