Hello Henrique,
Am 2008-02-23 18:00:39, schrieb Henrique de Moraes Holschuh:
> Well, I recommend you go to extreme levels of output harmonics filtering,
> that alone will increase system stability a damn great deal. Some tests
> using memory bit-rot testing a few years go (either by Ars Technica, or
> Tom's, I don't recall) nicely illustrated why one would want to do so.
In the specification "ATX12V" version 2.2 from 2005 is all documented
what is required. Some of the requirements affect only the AC-PSUs and
not DC-PSU's...
I have for example a 3.3V Step-Down regulator which support 100A and you
can put a 100.000µF Electrolyt condensator on it and then PowerOn the PIG.
I was realy surprised about this High-Integrated MOSFET Step-Down
regulator and its stability. I am using an 60MHz Oszilloskope with
memory and the stabilization was inside the ATX12V requirements.
And yes, Filtering the 24Vin is heavy... since I have no real
experience with it and need some stuff to read.
Can you suggest Literature in english or german?
> And don't think for a single moment that you are designing for linear loads.
> Computers are !@#$!@#$#@$ unhelpful loads, and the more efficient the
I am simulation some PIGs on my programmable Load... :-)
OK, currently I have only 3.3V stuff availlable, but It seems, I have
to build a test-environement. (I am using an USB-connected 48-Port
IO-Card which drive programmable loads from 0 to 100A and can switch
in less then 5ms, which is maybe not enough)
> power-saving features in use in a system, the worse its load profile is when
> it comes to harmonics.
...
> > Does anyone know, where I can get the specifications for it?
>
> Yes. http://en.wikipedia.org/wiki/ATX, look at the external links section.
I have gotten from two peoples the ATX12V sepecs, one v1.1 from 2000
and one 2.2 from 2005 and it seems, there is all described what I
should know...
It rest only the REAL amperage on the several connectors...
I have already written it in a previosly (initial?) message that I want
to build the DC-PSU modular, which mean, if you want only to power the
Mainboard since it is a router and the HDD is a CF-Card on the MB, you
will need only the ATX-Module which could be between 60 and 100 Watt.
Oh, currently I am preparing some infos (only provisory) on
<http://freenet-homepage.de/linux4michelle/to_replace/>
since I have the need for complete 36 DC-PSU's and I do not realy like
to develop them only for me since it is quiet expnsive for only 36
DC-PSUs.
> > How many ampers must a cable support?
>
> Cable choice depends on cable length, and acceptable voltage drop at given
> load levels. And you need to factor in in-rush and start current too if
> they are non-trivial (and they are non-trivial for disks, fans, and anything
> with high-drain CPUs or huge ammounts of RAM).
There are some real weird things in the ATX12V specification, since some
cables of my 600W AC-PSU have only 0.75mm² or 1.0mm² cables (arround 40cm
long) which definitivly do not support more then 10A whithou being
transformed into a heating-cable but the connectors should support
3.3V/18A or 5V/24A on the AUX Power connector.
> If you play the el-cheap-o game with the cables and electronics, you will
> get "nice" surprises when your systems face their first thermal challenge on
> the form of an unusual hot (or cool) day.
Thats not my route...
I can buy DC-DC-Converters from China but I have never seen sone, which
have an efficiency OVER 80% (ATX12V is talking about 66% but for AC PSUs
which are a VRY BIG no for my usage in Photopholtaik-Systems)
In the USA there are some Manufacturer which have ATX-Style DC-PSUs but
they cost between 320 and 580 US$.
I have currently not checked the Link from the UK, but I will try it
today. (currently I have no HSDPA access... do not know why)
So, I have found my microchips (e.g., High-Efficiency Step-Down
Regulators, Sequencers, OVP, and more) from Maxim, Dallas, NXP, AD and
others which fit my requirements.
The MAX8655 is one example... But you need to solder them InfraRed or
something similar, which should no problem for me... guess why!
The only thing which is currently not solved is the 24 Vin (18-30V) to
12Vout (and between 10 and 50A) which must be very stable and resistible
agains voltage waveing from the input... If this problem is solved, it
is possible to produce an DC-PSU with 300W (out) for less then 60 Euro.
Also I try to get an experience with UPS-Electronic and I am searchin
for this highly intergated solutions, which mean, I wan to put an USB
connector into the PSU which can be connected to a free USB connector
on the Mainboard and be read like any other UPS... so the 24Vin can
be whatched. There would be an solution for a DS80C411 which can
controll the whole DC-PSU and pull the data out of the USB-Port but
I think, this can be an extra module in the C-PSU.
Thanks, Greetings and nice Day
Michelle Konzack
Systemadministrator
Tamay Dogan Network
Debian GNU/Linux Consultant
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