230v AC to 5v DC converted (SMPS) with out transformer

Hello there,
I want to make a switch mode power supply (SMPS) which will deliver 5v DC from 230v AC.
I did Google the problem but all the solution and the datasheet offer solution which use transformer which I am not interested.
I find a small compact SMPS module which use 02 inductor, a 7pin integrated circuit (IC) and other components ( diode, capacitors, resistors). It is exactly what I was looking for but the guy made sure no one get his secret by scratching and deleting the writing ( label) on the IC.
I will be very pleased if any one know a chip which doesn’t use transformer to convert 230v AC to 5v DC.
Many thanks.
rabmerab

I give you suggest to use a buck-converter. But you don't give information about current

Thanks for the reply.
All the datasheet, I saw so far when using back-converter, you have to use a transformer of some kind which I can't due to resticted space. The PCB has to be 30mmx20mm and 10mm in hight ( it has been done before as I said in my previous post))
The current is 1A.

rabmerab said:

Thanks for the reply.
All the datasheet, I saw so far when using back-converter, you have to use a transformer of some kind which I can't due to resticted space. The PCB has to be 30mmx20mm and 10mm in hight ( it has been done before as I said in my previous post))
The current is 1A.

Click to expand...

You have to use transformer in order to have isolation. (Because input is 230V AC)
Look into "Quasi-resonant converter", it will have a transformer but small sizes, because of the high frequency, normally their frequency is above 500KHz rather well in several MHz.

Regards

Hi,
A possibility if you mean transformerless, is using an RCD-zener stepdown circuit, but you won't be able to get much current.
You could use LNK switch or TOP switch SMPS circuits and you'll get some good output at reasonably small sizes (depending on your PCB design).

Hope this helps.
Tahmid.

Tahmid said:

Hi,
A possibility if you mean transformerless, is using an RCD-zener stepdown circuit, but you won't be able to get much current.
You could use LNK switch or TOP switch SMPS circuits and you'll get some good output at reasonably small sizes (depending on your PCB design).

Hope this helps.
Tahmid.

Click to expand...

the RCD-zener stepdown circuit need a big capacitor to get 1A current , so the best solutions is back or sepic(two inductors)

pl clear me ,RCD-zener = ? ihave reqer.1 amp 12v &1amp 5v smps supply