The warning is purely because dubious quality USB-C cables won't be able to safely carry 90W. The USB-A doesn't have the warning because it can't do 90W.Admittedly it might be a compliance issue but no such warning is given for the USB-C/USB-A cable. It is capable of proving 90W for a laptop power/charge.
Looking at other info, the cable appears to have some signalling, whether that is a couple of resistors or an active device isn't clear.
It'll be an active cable. To get 90W you need a PD source that supports it, a PD sink that supports it and a smart/active/e-marked cable that supports it. And they all have to agree.
You can put more than 15W (3A @ 5V) down a USB C cable without USB PD. With PD you can't put more than 25W down it without raising the voltage above 5V as both cable and connectors are only rated for 5A.
Resistors may also be present on the monitor end but only to tell a non-PD USB host device whether it should provide power to it.
Statistics: Posted by thagrol — Sat Dec 21, 2024 9:08 pm
