Duet 3 powering via ext 5v



  • Looking for some clarification on using an external 5V power supply with Duet3 v0.6 board. The SBC that I am planning on using can pull 3-4A + screen usb etc. I plan to direct wire 5v to the SBC and to the Duet3 so that neither is pulling power through the board but parallel.

    I see the [ext_5v] 5V in and ground to connect the external 5V supply.

    Then for the jumpers I have become confused. Internal 5v En jumper (off) / SBC->5V (on?) / 5V->SBC (off).

    Or maybe just power the SBC separately from external 5V supply and leave the internal 5v enabled for Duet. Like 5V En jumper (on) / SBC->5V (off) / 5V->SBC (off)?



  • If you're direct wiring 5v to both the duet3 and sbc you want NO jumpers installed on any of the 5v options pins.



  • @gtj0 Thanks. Do you think that's the best way to go in my situation (direct wire both)?

    Seems that I could keep the internal 5v powering the duet (keeping protection intact) and external power the SBC. Also removing the +5V (pin2,4) from the ribbon cable.

    Is there a board schematic somewhere? I'm only seeing the duet2.sch on github



  • @Hutch118

    As long as the same power supply is powering both boards I think it's fine. That's how I have it. If you use the internal supply, you lose the ability to turn on or off the Vin supply from the ATX_PWR pin. If you're worried about protection, you could always place in-line fuses in the supply lines to each board. Don't worry about removing the 5v lines on the ribbon cable. As long as you have no jumpers on the 5v->SBC or SBC->5v headers, you're OK.

    I don't think @T3P3Tony has published the Duet3 schematics yet.


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  • @dc42 If I configure like the second option- "If you want the SBC to provide 5V to the Duet then remove the jumper from 5V->SBC and from Internal 5v En. Place a jumper on SBC-5V". Then power is going to the SBC then up the ribbon cable (pin 2,4) to power the Duet? Where does ext_5v fit here?



  • @Hutch118 Actually those instructions from the Wiki are incorrect.
    To power the Duet from the SBC you need both the 5v -> SBC and the SBC -> 5v jumpers installed.
    ext_5v does not fit at all. You can still use the ATX_PWR pin on that connector to control the Vin power supply though.



  • @gtj0 Thanks. And just to rest my mind [both the 5v -> SBC , SBC -> 5v jumpers installed and 5v En jumper (off)]. The power will go to SBC, up the ribbon cable to power the duet.

    I keep getting distracted on wanting to use those ext_5v pins because they are there. I don't know why this was so difficult for me. I've wired up a few other Duets honest 0-o.



  • @Hutch118 Yep, that's it!



  • @gtj0 !celebrations! ᕕ( ՞ ᗜ ՞ )ᕗ