TBH that’s what charger is for. Another name for charger is adapter, as the role of it is to adapt your 240V AC into the minuscule 5V DC.

The actual output from charger is only 5V (or 20V in 100W PD charger sense) DC.

Now back on TS’ query. The main concern here is the Voltage. Legacy phones only support 5V charging, eventually Qualcomm quick charge came out and mainstream started supporting 9V and eventually now 12V, 15V or even 20V. If the 100W charger have 5V modes, I don’t see why it wouldn’t work. Likewise, if it didn’t have 5V mode, your phone is also not that dumb to trigger the higher voltage mode than it’s designed to take. Both sides actually will communicate with each other and engage protocols (PD/QC/FastCharging/SuperCharge and etc, each brands have own protocols) check (charger, device and cable all need to comply with said protocols) before able to engage the high wattage charging.

This post has been edited by msacras: Aug 17 2023, 12:19 PM