Why USB-C Splitters Can Cause Magic Smoke Release

April 7, 2025 by Maya Posch 40 Comments

Using USB for powering devices is wonderful, as it frees us from a tangle of incompatible barrel & TRS connectors, not to mention a veritable gaggle of proprietary power connectors. The unfortunate side-effect of this is that the obvious thing to do with power connectors is to introduce splitters, which can backfire horribly, especially since USB-C and USB Power Delivery (USB-PD) were introduced. The [Quiescent Current] channel on YouTube recently went over the ways in which these handy gadgets can literally turn your USB-powered devices into a smoldering pile of ashes.

Much like Qualcomm’s Quick Charge protocols, USB-PD negotiates higher voltages with the power supply, after which this same voltage will be provided to any device that’s tapped into the power supply lines of the USB connector. Since USB-C has now also taken over duties like analog audio jacks, this has increased the demand for splitters, but these introduce many risks. Unless you know how these splitters are wired inside, your spiffy smartphone may happily negotiate 20V that will subsequently fry a USB-powered speaker that was charging off the same splitter.

In the video only a resistor and LED were sacrificed to make the point, but in a real life scenario the damage probably would be significantly more expensive.

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Need High-Power Li-Ion Charging? How About 100 W

October 4, 2024 by Arya Voronova 21 Comments

Ever want a seriously powerful PCB for charging a Li-Ion pack? Whatever you want it for, [Redherring32] has got it — it’s a board bearing the TPS25750D and BQ25713 chips, that lets you push up to 100 W into your 1S Li-Ion pack through the magic of USB Power Delivery (USB-PD).

Why do you need so much power? Well, when you put together a large amount of Li-Ion cells, this is how you charge it all at once – an average laptop might charge the internal battery at 30 W, and it’s not uncommon for laptop batteries to be dwarfed by hackers’-built packs.

A 4-layer creation peppered with vias, this board’s a hefty one — it’s not often that you see a Li-Ion charger designed to push as much current as possible into a cell, and the chips are smart enough for that. As far as the onboard chips’ capabilities go, the board could handle pack configurations from 1S to 4S, and even act as a USB-PD source — check the IC configuration before you expect to use it for any specific purpose.

Want a simpler charger, even if it’s less powerful? Remember, you can use PPS-capable PD chargers for topping up Li-Ion packs, with barely any extra hardware required.

HP WebOS TouchPad Gets With The USB-C Times

October 1, 2024 by Arya Voronova 9 Comments

Despite HP shuttering their WebOS project some time ago, the operating system has kept a dedicated following. One device in particular, the HP TouchPad, was released just a month before webOS went under and is still a favorite among hackers — giving the device the kind of love that HP never could. [Alan Morford] from the pivotCE blog shares the kind of hack that helps this device exist in a modern-day world: a USB-C upgrade for charging and data transfer.

The inline micro USB port used is a perfect fit for a USB-C upgrade, with only small amounts of PCB and case cutting required. Just make sure to get a breakout that has the appropriate 5.1 K resistors onboard, and follow [Alan]’s tutorial closely. He shows all the points you need to tap to let your TouchPad charge and transfer data to your computer, whether for firmware flashing or for daily use.

This hack doesn’t preserve the USB-OTG feature, but that’s fixable with a single WUSB3801. Apart from that, this mod is perfect for keeping your webOS tablet alive and kicking in today’s increasingly USB-C dominated world. Once you’ve done it, you might want to take care of your PlayStation 4 controllers and Arduino Uno boards, too.

Tiny ’90s Laptop Gets Modern Power

August 21, 2024 by Jenny List 20 Comments

The laptop to have here in the 2020s varies depending on who you ask, perhaps a Framework, or maybe a ThinkPad. Back in the 1990s the answer might have included a now-forgotten contender, because in that decade Toshiba made a range of legendarily tough chunky grey machines. Of these the smallest was the Libretto, a paperback book sized clamshell design which was an object of desire. It’s one of these that [Robert’s Retro] has upgraded to use USB-C power instead of the original power brick.

The full video is below the break, and while it first deals with replacing a defective screen, the power part starts just before 22 minutes in. As you’d expect it involves a USP-C PD trigger board, this time at 15 volts. It’s mounted in a small 3D printed adapter to fill the space of the original jack, and requires a tiny notch be removed from the corner of its PCB to fit round the motherboard. The rest of the video deals with reassembling the machine and tending to mishaps with the ageing plastic, but the result is a Libretto with a modern charging port.

Naturally a machine with a Pentium CPU and 32 megabytes of RAM is in of limited use in modern terms, but these Librettos remain very well-designed tiny PCs to this day. It’s great to see them still being modified and upgraded, even if perhaps there’s a limit to how far you can push their computing power. We’ve encountered the Libretto before a few times, such as when one was used to retrieve data from an old Flash card.

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A devboard with the CH32V003, with a few resistors and bodges, with a USB-C cable plugged into it, and a programmer plus an extra probe attached.

USB PD On CH32V003 Teaches You Everything

July 2, 2024 by Arya Voronova 5 Comments

How do you talk USB Power Delivery (PD)? Grab a PHY? Use a MCU with one built-in? Well, if you’re hardcore enough, you can do it with just a few resistors and GPIOs. [eeucalyptus] shows you their implementation of USB-PD on a CH32V003, which has no PD peripheral. This includes building a PD trigger, completely open source, and walking you through the entire low-level PD basics, too!

It helps that CH32V003 is a 32-bit MCU with a good few resources and peripherals, for instance, an internal comparator. Other than that, you don’t need much in terms of hardware resources, but you do need a steady hand — parts of the firmware had to be written in assembly to keep up with PD timing. Want to tinker with the fruit of this research, perhaps, further build upon the code? There’s an example board on GitHub, too!

Want to try your own luck with this method? There’s a schematic, and logic analyzer captures, and a board to refer to. Again, more than enough information on every single low-level detail! Otherwise, grab an MCU pre-programmed to talk PD, maybe a trigger board chip, or maybe even a PD PHY and implement PD communications with it directly – it’s pretty easy!

We thank [Julianna] for sharing this with us!

The splitter with a 3D-printed case and three yellow cables coming out of it, powering two phones and one powerbank at the same time

Split A USB-C PD Port Into Three Port-ions

July 1, 2024 by Arya Voronova 9 Comments

There’s no shortage of USB-C chargers in all sorts of configurations, but sometimes, you simply need a few more charging ports on the go, and you got a single one. Well then, check out [bluepylons]’s USB-C splitter, which takes a single USB-C 5V/3A port and splits it into three 5V/1A plugs, wonderful for charging a good few devices on the go!

This adapter does things right – it actually checks that 3A is provided, with just a comparator, and uses that to switch power to the three outputs, correctly signalling to the consumer devices that they may consume about 1A from the plugs. This hack’s documentation is super considerate – you get detailed instructions on how to reproduce it, every nuance you might want to keep in mind, and even different case options depending on whether you want to pot the case or instead use a thermal pad for a specific component which might have to dissipate some heat during operation!

This hack has been documented with notable care for whoever might want to walk the journey of building one for themselves, so if you ever need a splitter, this one is a wonderful weekend project you are sure to complete. Wonder what kind of project would be a polar opposite, but in all the best ways? Why, this 2kW USB-PD PSU, most certainly.

Design Review: USB-C PD Input For Yaesu FRG7700

May 23, 2024 by Arya Voronova 21 Comments

Today is another board from a friend, [treble], who wants to convert a Yaesu FRG7700 radio to USB-C PD power. It’s yet another review that I’ve done privately, and then realized I’ve made more than enough changes to it, to the point that others could learn from this review quite a bit. With our hacker’s consent, I’m now sharing these things with you all, so that we can improve our boards further and further.

This board’s idea is thought-out and executed well – it replaces a bespoke barrel jack assembly, and is mechanically designed to fit the screw holes and the free space inside the chassis. For USB-PD, it uses a CH32V003 coupled with FUSB302 – I definitely did help pick the latter! For mechanical reasons, this board is split into two parts – one has the USB-C port, whereas the other has the MCU and the PD PHY.

In short, this board is a PD trigger. Unlike the usual PD triggers, however, this one is fully configurable, since it has a 32-bit MCU with good software support, plus, the PD PHY is also well known and easily controllable. So, if you want special behavior like charger-power-dependent profile selection for powering a static resistance load, you can implement it easily – or, say, you can do PPS for variable voltage or even lithium ion battery charging! With a bit of extra code, you could even do EPR (28 V = 140 W power) with this board, instantly making it into a pretty advanced PD trigger, beyond the ones available on the market.

Also, the board has some PCB art, and a very handy filter to get some of the USB-C charger noise out. Let’s take a look at all of these!