Solder Ninja Dabbles In USB Power Arcana

USB first hit the scene in the 1990s, and was intended to simplify connecting peripherals to PCs and eliminate the proliferation of various legacy interfaces. Over 20 years later, it’s not only achieved its initial goals, but become a de facto standard for charging and power supply for all manner of personal electronic gadgets. If you asked someone back in 1995 whether or not you could build a USB-powered soldering iron, they’d have politely asked you to leave the USB Implementers Forum. But times change, and Solder Ninja is just that!

With a maximum power draw of 40 W, the Solder Ninja required careful design to ensure practicality. It supports a variety of USB power standards, including USB-BC 1.2, USB Quick Charge, and USB Power Delivery. This enables it to draw the large amounts of current required for the heating element. To make it easy to use with a variety of chargers out in the wild, it displays the current negotiated voltage and maximum current draw. This enables the user to understand the varying performance of the device, depending on the charger it’s plugged into.

Given the multitude of different USB power standards, we imagine [Nicolas] has the patience of a saint to perfect a project like this. We’ve seen similar builds before, too. Video after the break.


22 thoughts on “Solder Ninja Dabbles In USB Power Arcana

    1. When it comes to quick charging over USB yes, this is currently the case.

      I though personally will always go for the USB IF’s own standard above all else. Power Delivery 2.0 is the USB IF’s standard and is able to give 100 watts via 5 amps at 20 volts, so plenty of power for most applications.

      So Qualcomm’s Quick Charge isn’t of interest as far as I am concerned. Same goes for other non USB IF solutions.

      And if other people follow the same mentality, then there is soon only one standard in practice, and that standard being USB IF’s own standard. (After all, USB implementers forum is the ones deciding on USB related things, so why not use their power delivery standard?)

      1. Except from the USB-IF you now also have PPS added as an optional extension to PD3.0. Slightly more fragmentation direct from the source.

        Qualcomms quick charge 4 is a PPS superset and is at least back compatible with PD1.0 (or at least, my phone negotiated 9v charging quite happily on a 1.0 charger), 2.0, 3.0 and PPS.

      2. I feel pretty much the opposite. I choose standards based on a quick Google to see what the devices I actually want to use do.

        If something becomes an unofficial standard that’s more popular than the official one, I go with that for compatibility with more common stuff.

        At the moment, there’s tons of QC3.0 power banks and phones, so I’m not entirely sure why the maker community doesn’t seem to like it as much.

          1. For real? Not sure I like that choice when QC3.0 was already the accepted standard for almost all cheaper gear, but I guess PD is a thing now.

            Probably better long term because PD itself is seriously amazing besides the fact phones don’t use it outside the high end. Maybe we can finally stop using 2.1mm barrel jacks for voltages above 12v.

      3. “After all, USB implementers forum is the ones deciding on USB related things, so why not use their power delivery standard?”

        That’s a great question… the Nexus 5X and 6P, now four years old, support USB-PD and do so admirably, yet my HTC U11, at just over two years, only supports QC 3.0 for fast charging. What gives, HTC? (I know they’re in shambles now, but they weren’t when they designed the U11.)

    1. That’s precisely what I was thinking – I want one of those, but without the soldering iron part. Though that does exist, sort of, except of course standards change and expand, the things you wish to power the same, and after a while, your ultimate WTF-is-this-port-doing status device is another USB gadget in the mix that kinda works, well enough at least, as long as you don’t bump into the wrong standard.

  1. Take. My. Money.

    Can’t wait, but why the 18watt limit? With support of 20v up to 100watt us in the realm of possibilities.

    What was the reason to limit the output? 40 watt would be amazing!

    1. Hi Oliver, and thank you for your interest!

      I’ll admit it was very tempting to design it to make use of the full 100W of the Power Delivery standard. And you’re raising a legitimate question that I’ll try to answer as best as possible below.

      The RT tips are rated for 55W. So that’s your first upper limit right there. With the latest Power Delivery standard, going above 27W implies using voltages of at least 15V. But the tips also have a rating of 12V. The goal here being long-term reliability over absolute performance, I didn’t feel confortable feeding the tips with a PWM-ed >12V supply. It might have worked just fine, but it might also have ended up slowly damaging tips over time. Instead, the current design makes use of a DC-DC converter. And there you have it, the real upper limit: there is only so much current that can flow through in a switching supply that fits in such a small form factor.

      Hope that makes sense.

      1. Thank you for taking ng the time to respond and explain.

        Ignoring the regulator for a moment, I think all your points are upr valid and sensible. But whatbif higher performance tips become available? I would rather have the iron to be future proof in that regard.

        Now for the regulator, that seems to be the hard limit then. That does make me sad, as having a bit more (future) power would be god. Also allowing potential overclocking, at my own choice and risk of course.

        Looking much forward however to this!

        18 Watt beats 0 ;)

        1. Haha. Yes, the 40W is a hard limit, although you could probably increase it slightly by changing a few resistors, I would need to do the math again.

          That being said, the results are already impressive at 5V x 2.4A = 12W. That was probably my biggest surprise of this entire project.

          More power only means faster heating time, and better ability to solder on surfaces with high dissipation. And I found out that most solder jobs actually require limited amounts of power in bursts, but it’s definitely nice to have the ability to go all the way up to 40W when needed.

          1. Wait what? How did I get confused by 18 watt? Where did I pull that number from. 40 watts is actually pretty good. Granted 100watt for the iron as a max would be amazing, but even at 40 its perfect for me.

            When and where can I buy it.

            I repeat,
            Please. Take. My

  2. Yes, I hope this catches on and becomes the standard. Looks like a very cool design.

    What should we do about the ESD protection, though?

    On the other hand I feed that USB is not in enough devices. It pisses me off that cameras, shavers and a multitude of other devices I carry while travelling still act like spoiled kids and want their own particular charger that is useless for something else.

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