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BBG and some PSU problem

Hello friends,
As you probably know know, for normal start BBG board need fast +5V voltage rise from PSU, if you use powerful transformer PSU you can have problem with autostart KiwiSDR after power outage.
Info from!topic/beagleboard/aXv6An1xfqI[151-175]: "The BBG uses the TPS65217 power management IC. Per the data sheet, it will not turn on if the applied power has a ramp of greater than 50 mSec."

I have this problem with one of my PSU's, when BBG don't start after power lost and I installed device with 10s delay for allow power from PSU and it was very helpful for me:

Maybe this info was halpfull for something else. :smile:

73! Yuri


  • Thanks Yuri. The price is certainly right. Linear power supplies are great for reducing noise. But one problem is that sometimes they use very large output capacitors to reduce ripple and noise. And at power-on that cap looks like a dead short to the power supply and can take considerable time to charge up. Hence you get an output ramp that violates the 50 ms slope spec of the Beagle PMIC and it refuses to power-on because it cannot properly start its own internal SMPS regulators under those conditions (a possible damaging condition to the Beagle CPU if the power cannot be sequenced properly).

    A device like this can also provide a delay for a router (e.g. providing DHCP) to recover after a power fail properly before the Kiwi attempts to access the network. This is also sometimes an issue, although the Kiwi software startup has a built-in 30 seconds delay just for this scenario.
  • I put these in service on my KiwiSDRs and today the power company had on and off conditions for awhile. I set the time on for a 90 second delay. All the boards came up 90 seconds after the power and were operational. Well worth the time and cost to put in the line.
  • Is there an easy way to encase it? I see some other devices have a box included or as option.
  • @Bjarne I use small plastic box from screws but may be seller can add original box if you ask him...
  • edited December 2019
    I used a plastic box (Waterproof Sealed Power Junction Box 100x68x50mm) that are sold on eBay, 6-32 x 5/8" STAINLESS STEEL PAN HEAD screws that I had on hand, and 50x DC022 2.1x5.5mm Headphones DC Power Jack Plug Panel Mount Connector for the power connections. I shortened the screws with side cutters and added little stick on feet to the bottom of the box. If you buy these things, be sure to get the 5v model. The 12v and 24v models won't work on 5vdc power. (DC 5V 12V 24V LED Display Cycle Delay Timer Switch Turn ON/OFF Relay Module PLC)

  • Thanks, I have a few plastic boxes at hand actually, and spacers too to lift the board a bit. Btw the seller informed me today that they would sell optional boxes "next year". Yeah, right...
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