Better characterization of suspend current

Andy Green andy at
Fri Feb 8 13:17:15 CET 2008

Hash: SHA1

Somebody in the thread at some point said:

> (*) Note: some of the supplies you saw in the lab in Taipei are actually
>     extremely fast and should simulate a battery quite accurately. They
>     also cost about as much as a good oscilloscope ...

No they would simulate a battery badly, they have pretty much infinite
"stiffness" for any current below their limit threshold.  If you pull
300mA or 1mA the bench supply provides 4.00V or whatever you set.  A
battery doesn't act like that.

> Bench supply tests would still be useful for tracking down leaks and
> such.

It's fine for just assessing the different current drawn at different
supply voltages.

But the fact everyone was using them is a bigger problem in a different
way -- nobody but NOBODY was testing the device behaviours with a
battery as it will ship.  It was like a silent agreement nobody wanted
to "go there" because of the suspicion bad monsters were hiding.  That
sucks.  We are quite well armed to kill monsters now so its fine to let
us know where they might be hiding even if it sounds frightening to
start with.  For sure the guy that said he saw a bad thing isn't going
to get BLAMED for it, he's going to get THANKED.

- From now on every time we see development taking place in a different
way than the usage scenario, we should become immediately suspicious
somebody detected monsters and routed around the nest and go stick our
nose into what is going on.

- -Andy
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