Re: power supply discharge

On Fri, 27 Sep 2024 08:07:29 -0700, 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.

Twiddling the adjustment knob on a bench supply doesn't
represent a dramatic change - and most adjustible
supplies don't load their output terminals with a
lot of capacitance.

DC coupled programable supplies, or bipolar programmable
supplies are made to drive loads in the first and third
quadrants.

There are issues in the second and fourth quadrants, where
the supply is expected to absorb power.

An amplifier driving a pure reactance experiences the same
losses as driving a dead short.

RL