Homebrew_PCBs

----- Original Message -----
From: "J" <wyninejr@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, April 04, 2006 6:57 PM
Subject: [Homebrew_PCBs] fluorescent Bulbs


> Hello,
>
> Has anyone made a circuit that has something like some digital logic
> amd a pic with some long conductor paths that will drive a fluorescent
> bulb? Currently I am isolating the AC signal by having an analog
> ground plane that is isolated from the digital ground plane. There is
> a common ground area in which both planes are connected by a path that
> is at least .50 inches wide. Has anyone done something similiar and
> how much noise did the bulb create? Any ideas on how to keep the
> noise from traveling from the AC ground plane to the Digital ground
> plane via the common ground area? Should I keep the pathway to the
> common ground area to a certain minimum? Any help is appreciated!
> THANKS!

Try connecting the digital and analogue ground planes only at the supply
ground.

Leon

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> Hello,
>
> Has anyone made a circuit that has something like some digital logic
> amd a pic with some long conductor paths that will drive a fluorescent
> bulb? Currently I am isolating the AC signal by having an analog
> ground plane that is isolated from the digital ground plane. There is
> a common ground area in which both planes are connected by a path that
> is at least .50 inches wide. Has anyone done something similiar and
> how much noise did the bulb create? Any ideas on how to keep the
> noise from traveling from the AC ground plane to the Digital ground
> plane via the common ground area? Should I keep the pathway to the
> common ground area to a certain minimum? Any help is appreciated!
> THANKS!

--- In Homebrew_PCBs@yahoogroups.com, "J" <wyninejr@...> wrote:

............ >Currently I am isolating the AC signal by having an
analog
> ground plane that is isolated from the digital ground plane. There
is
> a common ground area in which both planes are connected by a path
that
> is at least .50 inches wide. ....... >Any ideas on how to keep the
> noise from traveling from the AC ground plane to the Digital ground
> plane via the common ground area? ........
>


Texas Instruments have numerous documents on PCB design on their site.
The following artical addresses keeping Analogue and Digital ground
planes seperated, amongst other points. There could be an answer here.
http://focus.ti.com/lit/an/slyt166/slyt166.pdf