Path: ...!2.eu.feeder.erje.net!feeder.erje.net!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: liz@poppyrecords.invalid.invalid (Liz Tuddenham)
Newsgroups: sci.electronics.design
Subject: Re: power supply discharge
Date: Fri, 27 Sep 2024 20:19:24 +0100
Organization: Poppy Records
Lines: 43
Message-ID: <1r0k861.zkmnet7s02tcN%liz@poppyrecords.invalid.invalid>
References: <c5idfjp9miqru154ei6tnmg8m14qd30m6d@4ax.com> <1r0jx0j.1upucutkl7g4iN%liz@poppyrecords.invalid.invalid> <n5pdfjdp453652lsud1gi03tpsd3r9r96n@4ax.com>
X-Trace: individual.net TN5fb70xMNniNOUbm6SZwQO7BIZjQ+9V/60H/zRl9nlCq/D4Us
X-Orig-Path: liz
Cancel-Lock: sha1:yvx8xFOqcdjNv4aDR6jI3fNawdI= sha256:L73PuhbeJsGS+D6OICauH3qZfk1SZ2lThSG1yPZShEU=
User-Agent: MacSOUP/2.4.6
Bytes: 2558

john larkin <jl@glen--canyon.com> wrote:

> On Fri, 27 Sep 2024 16:17:42 +0100, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:
> 
> >john larkin <JL@gct.com> wrote:
> >
> >> Given a benchtop power supply, you can turn the voltage up and then
> >> down, and it goes down. Most have a substantial amount of output
> >> capacitance, and can be driving an external cap too. So something
> >> pulls the output down.
> >> 
> >> I guess that there are no standards for this, but I've never seen a
> >> supply that just hangs high when it's cranked down.
> >> 
> >> I'm designing some programmable multi-channel power suplies and that
> >> is one of many tangled issues in the project.
> >
> >A DC-coupled audio amplifier chip might work as a fully-controllable
> >bi-directional power supply if your current and voltage requirements
> >were fairly modest.  They have the advantage of being relatively cheap,
> >well-protected and very fast (by power supply standards).  Some of them
> >have the tab at input earth voltage, so they don't require isolation
> >from the heat sink.
> 
> Unfortunately, it has to be a switching regulator.

Years ago there were power supplies with a linear regulator fed from a
thyristor chopper, the voltage to the linear stage being held just above
the required output.  This gave all the benefits of a linear power
supply without the dissipation.  

Perhaps you could use the switcher to power the audio amplifier?

....or were you thinking of using the switcher in reverse to feed excess
power back into the supply?  (That's where dynamotors and rotary
converters scored.)


-- 
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk