Re: Grounding Problem on AC and DC circuit

From: Fred Bartoli (fred._canxxxel_this_bartoli_at_RemoveThatAlso_free.fr_AndThisToo)
Date: 03/02/05 

Date: Wed, 2 Mar 2005 22:16:23 +0100

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> a écrit dans le message de
news:4R8LywFCiiJCFwdw@jmwa.demon.co.uk...
> I read in sci.electronics.design that Fred Bartoli <fred._canxxxel_this_
> bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote (in <422622fd$0$31344$6
> 36a15ce@news.free.fr>) about 'Grounding Problem on AC and DC circuit',
> on Wed, 2 Mar 2005:
> >Oh, another idea: just replace the power resistors by 2 diodes, and the
> >pb is solved.
> >
> >
> > +-+-----------------
> > A A
> > --------+-----+ | power
> > -----+--|-----(-+
> > | | A A
> > | | +-+-----------+-----
> > | | |
> > | | |
> > V V |
> > - - |
> > | | +-+-----------(-----
> > | | A A |
> > | '-----+ | | low power
> > '--------(-+ |
> > A A |
> > +-+-----------+-----
> >(created by AACircuit v1.28 beta 10/06/04 www.tech-chat.de)
> >
> >Be sure to have the AGND and GND well connected: if they get
> >disconnected, you've lost the low power supply.
>
> Doesn't that get you 320 V DC out of the 'low power' supply (assuming
> the bridge diodes and/or filter cap don't explode)?

Sure.
According to the OP, the low power supply is to be powered directly from
mains and have a non isolated stepdown converter thereafter. I don't know
why such an arragement, but that were the inputs. 

-- 
Thanks,
Fred.
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