J
Joerg
Guest
D from BC wrote:
Sluggish? How fast do you need it to be? I haven't seen loops much past
a couple hundred kHz in switcher.
I had used optos up to 10Mb/sec, no problem. The only reason I kicked
some out and replaced them with signal transformers was because the
signal transformers were multi-sourceable and 5c cheaper back then. That
has changed though.
--
Regards, Joerg
http://www.analogconsultants.com/
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On Fri, 27 Feb 2009 16:11:49 -0800, Joerg
notthisjoergsch@removethispacbell.net> wrote:
qrk wrote:
On Thu, 26 Feb 2009 19:40:45 -0800, D from BC
myrealaddress@comic.com> wrote:
I've seen a few schematics of opto's being used in linear mode for
smps designs..
But what about those digital isolators? Are they just for digital
circuits?
Right now I'm working on applying a digital isolator for a smps
design..
http://focus.ti.com/lit/ds/symlink/iso721.pdf
Note that the datasheet doesn't mention smps applications. hmmm
Anybody know some design examples of smps's using digital isolators
(opto digital, galvanic, GMR or RF)?
D from BC
myrealaddress(at)comic(dot)com
BC, Canada
Posted to usenet sci.electronics.design
I use both in switching power supplies. The analog opto for voltage
feedback, the digital isolator (Analog Devices ADuM1200 series) for
setting power supply voltage.
Three bucks for an isolator in a switcher? Yikes.
Relative to sluggish optos, the galvanic ISO721 is not cheap.
Probably the only reason I'm using it is to dodge modelling a fast
opto in ltspice.
Sluggish? How fast do you need it to be? I haven't seen loops much past
a couple hundred kHz in switcher.
<scratching head>Another reason I'm dodging a linear opto is that my smps design is
experimental and a poorly applied opto may cause loop stability
problems. If anything goes wrong, I can't blame an opto if it's not
there.
It's a tradeoff.. So the parts are expensive, but I get the design
done earlier.
I had used optos up to 10Mb/sec, no problem. The only reason I kicked
some out and replaced them with signal transformers was because the
signal transformers were multi-sourceable and 5c cheaper back then. That
has changed though.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.