By now we’re well under way with the consolidation of low-voltage power supplies under the USB-C standard, and the small reversible connector has become the de facto way to squirt some volts into our projects. But for all this standardization there are still a few places where the harmony of a unified connector breaks down, and things don’t work quite the way they are supposed to. One such case has occupied [James Ide] — devices which will accept power from a USB-A to USB-C cable, but not from a USB-C to USB-C one. His solution? A small flexible PCB upgrade.
The problem lies with how different power supplies and peripherals identify each other, and quite likely in device manufacturers skimping on a few components here and there. A compliant USB-C power supply expects to see pull-down resistors on the data lines, and will thus refuse to serve power to devices that don’t possess them. Meanwhile the USB-A supply will quite happily serve juice without such checks, which is what the manufacturer is relying on. The solution is a tiny flexible PCB with the resistors, designed to be retrofitted behind a USB-C socket. On one hand it’s probably one of the simplest circuits we’ve ever shown you, and on the other it’s a cleverly designed solution to the issue at hand.
If the nitty-gritty of USB-C interests you, then we’ve taken a much closer look in the past.
Thanks to [Andrea] for the tip.
nice one!
Oh neat. I got a set of really good AKG wireless headphones I got from Samsung with my phone that really needs this mod.
I got probably the same headphones with my Note 10+ 5G preorder. I was baffled that the headphones didn’t include a charger (A2C cable only inc) and wouldn’t charge from the phones charger. I keep them in the car but can’t charge them from my PD C2C charger in the car that I use for my phone.
So much for simple standard that supports all the things. USBC is the most difficult connector to predict what will happen when you connect 2 given devices with it…
I’ve got an S8 which from looking on ebay seems to suffer a not that uncommon issue that is the reverse of here. With an A-C cable, it screams ‘water in the charger port’ and refuses to charge, regardless of what cable you use and what charging device, always the same. C-C cable always charges without issue!
The S8 can charge from a USB A to C (I do it all the time).
https://www.amazon.co.uk/Samsung-EP-TA20UBE-TWO-THREE-Packaging-Black/dp/B09QBC7C9X/ref=sr_1_3?keywords=Charger+for+Samsung+S8&qid=1660745800&sr=8-3
I’m not saying it can’t, but it seems to be somewhat common issue on some S8s that they say water detected when charging from an A charger (yes the original Samsung charge & cable do this). Initially it was fine, happened a few months down the line.
If stuck with an A charger, the ‘fix’ is to power off the phone, connect the charger then turn on.
You just need to clean your phone port. It’s the combination of the resistance on the crap in the port and the voltage used by the charger to detect the pull down resistors on the data pins. The phone is calibrated to report water if there is any greater voltage than what we normally there for the detection. If you have any conductive dirt in the port area it will cause it to detect water. A USB a2c cable only uses one side of the side is the port, where c2c uses both, the there is likely only enough crap on one side. On my S8 active it would do it sometimes with a2c cables and sometimes with c2c and a2c. Just use the eye end of a needle and clean the crap out of the port. The try again.
What he said … Except use something nonconductive like a toothpick
That’s definitely not normal. I’ve had 2 s8+ since launch and my mother still uses one of them. Only charges from a-c never got that message on it. Got it once in my s22 ultra but I just cleaned the port and the magnetic tip I use and it’s working fine.
Very useful article, thank you, I was unaware of this issue but it explains a lot of problems I have observed when mixing and matching chargers, cables and devices.
Very good idea. I can see uses for this way of making mod-pcbs for all sort of uses. Like adding probes or debug port to fine pitch ICs.
You solder this on your device and not the powered port, correct???
This is a wonderful hack and exactly the spirit I look for from this site! Kudos!