Searching \ for '[EE]: 1:1 Transformer...' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/power.htm?key=transformer
Search entire site for: '1:1 Transformer...'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: 1:1 Transformer...'
2002\12\04@182102 by TNT

flavicon
face
Hi All,

I want to build a BASIC FLYBACK to isolate the serial communication on a PCB
(485).  I want to supply the isolated section by a transformer.  Do you any
idea for the transformer...

I was using a MAX243 with a coilcraft transformer, but it is too
expensive...

Thanks a lot,


_____________________________________________________________________
Envie de discuter en "live" avec vos amis ? Tilicharger MSN Messenger
http://www.ifrance.com/_reloc/m la 1hre messagerie instantanie de France

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\12\09@025524 by Vasile Surducan

flavicon
face
I have never seen an 485 optoisolated at the output line...
Just because you'll have a lot of problems with line impedance.
Use optocouplers isolation ( you need three ) and a separate power supply
for line driver/receiver.
However, if it works with 1:1 transformers and at least 30 devices on one
1200m EIA485 line, please let me know ! It should be interesting !

If you mean by basic flyback, an isolated power supply, then computing the
transformer means only using the Faradys law at a known F and B

regards,
Vasile
http://www.geocities.com/vsurducan


On Wed, 4 Dec 2002, TNT wrote:

{Quote hidden}

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


2002\12\09@131330 by Spehro Pefhany

picon face
At 06:19 PM 12/4/02 -0500, you wrote:
>Hi All,
>
>I want to build a BASIC FLYBACK to isolate the serial communication on a PCB
>(485).  I want to supply the isolated section by a transformer.  Do you any
>idea for the transformer...

Why exactly would you select the flyback topology for this application?

>I was using a MAX243 with a coilcraft transformer, but it is too
>expensive...

Do you mean MAX253?  It's convenient, but can be replaced with some
standard parts at a component cost savings (not to mention availability).

Usually you design the transformer along with the rest of the circuit for
DC-DC converters. See Pressman, Billings etc. for the gory details.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
spam_OUTspeffTakeThisOuTspaminterlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics


More... (looser matching)
- Last day of these posts
- In 2002 , 2003 only
- Today
- New search...