Re: for Anand Dhuru

[nobody@xxxxxxxxxxxx (Dave Houston)]

Anand,

If you look at p12 of the TDA5051A app note, it details coupling to 230V
mains with an LC bandpass filter (no transformer).

I've also seen AN236 (?) from Microchip which I think is the one you're
referring to. I've tried that coupling on a breadboard using a PIC12F683 and
found it difficult to get much signal to the powerline.

If you plan a serial interface to the PIC you'll need isolation.

I recalled another app note that uses the same Toko T1002N transformer but
with a transistor line amplifier. It's for the ST7537 which has been
replaced by the ST7538. These are FSK modems but I think you're mostly
interested in the line coupling.

     http://www.st.com/stonline/books/ascii/docs/1124.htm

Which PIC are you planning to use?

"Anand" <ardhuru@xxxxxxxx> wrote:

>Hi Dave, thank you very much for the pointer; I found it very
>informative and can certainly take some pointers from the math they
>have explained.
>
>BTW, some folks at the piclist also directed me to an app. note on the
>X10 site that essentially uses a 16F877A as an X10 controller. Of
>special interest was the way they had connected to the mains *without*
>a transformer. I wonder if the coupling would be as effecient?
>
>You might be surprised by my reluctance in using a transformer, but
>thats basically because trasnformers available here are kind of
>generic; they do not have any markings, nor brand mentioned. One just
>goes by the color of the slug, and hope for the best. In my case, I've
>found the one with the white slug (2nd stage IFT?) seems to work the
>best.
>
>Again, thanks.
>
>Anand
>
>>
>> I just referred someone else to an application note on the Philips TDA5051A
>> powerline modem. It's at...
>>
>>      http://www.michat.com/pdf/GB/5051_APP.pdf
>>
>> Page 19 shows coupling to the powerline using a Toko T1002 transformer. I
>> think you'll be able to find that one. While Digikey lists it as non-stock
>> you can order from them. You might also find it elsewhere.