| > When plugged in, it's in a very limited 5V state. Depending on what's on the other end, it's actually even better than that would imply most of the time. If both sides of the cable are in spec-compliant USB-C ports, then the power pins will be left at 0v for the initial connection, and only the CC pins will have a minuscule amount of power coming from the source (charger) - just enough to detect specific levels of resistance on the sink (phone/laptop/etc.) for 5v power and/or negotiate a higher voltage for USB PD. Once they've established that one side is a source and the other side is a sink, then the source will provide power on the power pins of the cable. If a USB-C cable is used to connect one charger to another, for example, then the negotiation will fail and neither charger will provide power on the main power pins. USB-A ports, on the other hand, always provide 5v, so USB-A to USB-C cables always provide 5v on the main power pins. The reason some cheep chineese electronics with USB-C connectors can only charge with USB-A to USB-C cables, not with USB-C to USB-C cables, is that they skipped the CC pins entirely. I actually modded one device by adding in two half-cent resistors to make it able to charge from a USB-C port: https://www.nfriedly.com/techblog/2021-10-10-v90-usb-c/ |
If anyone has a usb-c pass through adapter that can negotiate for 5v out, please please please share. Ideally for me it'd be a like 3 inch cable that that a male & female connector.
Extra credit if it uses usb-pd to try to ask for 5v 5a.
(these would be incredibly out of spec & could cause damage to systems, but mercy they'd be useful! I find this problem to happen on a bunch of devices, alas not just cheap/rare ones)