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how does blackdog's PSU work?
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T3sl4co1l:
Now that's much more reasonable, 1.5A step and a simple blip.

I don't get why it looks so ragged, if that's a noise thing or a trigger thing or what.  Or why the trigger is off at 239ms, maybe that has something to do with it?  Dunno.

But this doesn't resolve the inconsistency of the earlier screenshot.  If I had never seen that at all, I'd have no reason to doubt this!  But with?  I don't know.



--- Quote from: Kleinstein on March 19, 2018, 05:03:59 pm ---The load test at 9 A is rather short - it's only 200 µs.  The current limiting needs some time to respond and in this example it looks like the 200 µs are shorter than the response time of the current regulation.

--- End quote ---

Shouldn't be a problem here -- offhand, if the current error amp has to slew 5V (it should really only be about 2V), it can do that, in and of itself, in less than a microsecond; and with about 100pF effective integration capacitance and a few kohms connected thereto, it'll only take about a microsecond.

So I'm still perplexed how the circuit (if it was, in fact, built and measured as shown) could do that.



--- Quote from: blackdog on March 19, 2018, 06:24:13 pm ---The points that Tim touches I have a different opinion, and yes Tim, like me, is entitled to his opinion.
And yes, I think that Tim does have good knowledge of electronics, but I am not crazy either.

--- End quote ---

Please understand:

I don't give a shit about opinions.  My opinion doesn't matter.  Nor do other's.  Brains conflate or fabricate all sorts of things.  Brains filter everything through their own experiences.  Everyone's opinion is so different as to be useless noise.  And that is why, as they say: "talk is cheap".  Because it's not worth anything.

What I'm after is hard data.  Numbers.  Measurements.  Facts.

Instruments don't lie.  They might be connected wrong, they might be set wrong, but once all of those factors are determined, there can be no lie.

I mean no offense by my frankness.  I just don't find pleasantries useful.  Circuits certainly don't care; you can stick them with a burning hot soldering iron and they beg for more. ;D

HTH,
Tim
BravoV:

--- Quote from: blackdog on March 19, 2018, 10:09:06 am --- I am from XXXXX in the ZZZZZZZZ, that means that I am direct and do not lie , and no bullshit.

--- End quote ---

For you actually its never about electronics, its all about attitude, and pretty bad one.  :--
BravoV:

--- Quote from: T3sl4co1l on March 19, 2018, 07:11:56 pm ---I mean no offense by my frankness.  I just don't find pleasantries useful.  Circuits certainly don't care..........
--- End quote ---

This  :-+, which my self and also believe a lot of others here looking at their responses to you, don't mind at all, and I have learned a lot from you here in this forum, thank you.   :clap:
exe:
Guys, please be polite and respectful to each other.

Concerning PSU, there are tiny bits that could be done differently, but who cares? Final performance is that matters. Also, as I understand, each building block was comprehensively evaluated. So, I guess, if I start substituting components it's not granted I'll get the same performance (quite likely the opposite). No offence, but I think not everyone knows/understands/appreciates how much effort was put into design of this PSU (I know this because I read that circuitsonline.net thread, as well many others to better understand this circuit). Because it's so popular, people like to challenge this circuit, but not always with enough respect, imho.

It's that I'm defending blackdog (although I would), it's my personal opinion based on my personal experience in designing power supplies (I designed 4 or 5 of them, all garbage, to be honest). That's why I'm looking for a good not-too-overcomplicated PSU that I could "enhance" with an MCU :).

Aaanyway, it's time for silly questions :)  Is a separate isolated power supply needed? Can I just use a charge pump to generate some voltage above the output? Let's say I can sacrifice some noise performance (my PSU enclosure is not shielded (plastic), so I'm not going to get microvolts of noise even if I try hard).
Cerebus:
While we're on the subject of testing PSUs with step loads: A while back I was comparing specs of a bunch of bench power supplies on the typical 50% to 100% current load step recovery time test. The reason for this was to develop a set of target test specifications for a PSU I was designing. What was conspicuous by its absence in those specs were specified slew rates for the waveform of the applied test load.

What I'd found testing my own design in simulation was that I could get as stable as I liked but if I went to too fast an edge for the test load then it would (kind of obviously) all go to hell in a handbasket. So I wanted to know what slew rate was reasonable to test against. (Obviously in simulation I was able to apply physically improbable/impossible edge speeds.)

So, the question is: What is a reasonable slew rate for an applied step load when testing PSU regulation recovery times? Are there industry standards? (I couldn't find evidence of any.) Or do people just test with whatever slew rate the electronic loads available to them support?
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