[hpsdr] PicoPSU power supplies

[Dan Babcock]

Hi Pete,

Any observations on the noise generated by the wide input PicoPSU? 


73,

Dan N4XWE



________________________________
 From: n3evl <n3evl at townisp.com>
To: hpsdr at lists.openhpsdr.org 
Sent: Saturday, February 4, 2012 1:02 PM
Subject: Re: [hpsdr] PicoPSU power supplies
 
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Sounds like you'd have been better off with the PicoPSU-120-WI-25 converter whichaccepts 12 - 25V input.  I'm using one of these with my HPSDR equipment and supplying it with the usual 13.8V from a bench top PSU

Pete, N3EVL



On 2/4/2012 2:48 PM, John Ackermann N8UR wrote: 
***** High Performance Software Defined Radio Discussion List ***** 
>
>Sorry for the cross-post, but I know this is of interest to some
      folks on the HPSDR (high performance software defined radio) list,
      and I suspect it may be helpful for some time-nuts as well. 
>
>The important message first: the little "PicoPSU" switching power
      supplies that plug directly into an ATX socket say they are for
      12V input.  It turns out that they mean it -- the supply will shut
      down if the input voltage is more than 13 - 13.5 volts.  So using
      these in a typical battery-powered environment is potentially a
      problem unless you somehow drop a volt or so. 
>
>Here's the sad story... 
>
>I recently built several low power Atom-based computers that use
      the PicoPSU supplies.  The theory was that I'd run these machines,
      along with all the other 12V gear in the basement, off a couple of
      big batteries on a float charger.  The battery voltage varies from
      about 13.5 to 14.2 depending on the charger state. 
>
>Built the machine on the bench using an Astron supply, and
      everything was cool.  Put on the battery bus in the lab, and
      things got very funky.  Sometimes the power LED would come on, but
      nothing more would happen.  Take the machine to the bench,
      everything was fine.  Take it the lab, didn't work. 
>
>I checked all the power connections and found no problems, but the
      battery supply simply would not run the computer. 
>
>Finally, I found a manual for the PicoPSU on the web, and
      discovered that when they say it's a 12V supply, they mean it --
      there is an overvoltage shutdown that's supposed to trip between
      13.0 and 13.5 volts.  In practice, it seems that at least some of
      them are good for a little bit more than that, because the 13.8V
      from my bench supply worked OK.  But when the battery voltage hit
      about 14.1, that was too much and the supply shut down. 
>
>So, I now have the computers running from an Astron supply that I
      adjusted for good measure down to 12.6 volts, and all is well. 
      For the long term, I'm considering putting a diode or two in
      series with each computer's power lead to drop the voltage that
      way. 
>
>John 
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