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[SOLVED] What is this call ? 110-220 AC stepdown to 12 DC 1A without

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I looking for power supply circuit
that input 110to220V AC
output 12V DC 1A
but don't use transformer like mobile
wall charge, notebook.. etc.

a tiny circuit is very good.

How you call this circuit ?
I don't know keyword to search.
Because I am Thai.

Have a good day.

Try Calling it a "Switched Mode Power Supply"
Good luck.

For "Switching mode power supply" topology, it also need a large inductor for energy store, so a large "transformer" cannot be eliminated in Switching mode design.


Thanx all. Look very complicate for new hobbie.

How it auto detect input voltage 110-220V ?
or they use chip IC control ?

Maybe I have to buy small SMPS module kit
in my local area. Thailand.
or buy the old mobile wall charge.

Hi Tong,

I think you can name it as a "transformerless AC/DC converter" and search for it that way as well.
Switch-mode power supplies employ PWM control (Pulse-Width Modulation) and it can also be used for sensing the input AC from 85V to 240V. But these circuits do include a transformer so do not refrain from it. If so,I can suggest visiting the Power Integrations Inc's URL at the maker of clever control IC for such mains AC/DC converters the TOPSwitch family. They have application notes and even design ideas in Acrobat PDF format.



On 2001-11-14 12:25, tong wrote:
How you call this circuit ?
I don't know keyword to search.
Because I am Thai.

Withour a transformer or inductor for 1A I would call it impossible ! For up to about 100 ma you can drop the voltage using a capacitor. Over that you have to have a transformer or at least an inductor and a switching supply. Power integration has some nice IC's that are quite simple to use. But beware, you need the right components, specially for the transformer and diodes.

Best regards,

Have a look in the wdbsite for PICO transformers and dc dc converters..

Further have a look at new TI switching doesnot say your exact purpose but it will give you lot of information towards ur subject

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