USB Power Delivery (PD) Receptacles
The USB Power Delivery (USB PD) is a fast-charging technology based on the USB-C standard. It utilizes its high power output and an adjustable voltage supply to optimize charging based on your device’s consumption needs. Whether you are charging your headphones or a laptop, the USB PD, can safely and quickly recharge your device’s battery.
Why is the USB power delivery receptacle rated in watts? Not amps?
Standard USB devices (non-power delivery) use constant voltage (5V) to charge your device. Current is the only variable in this situation (1-5 Amps typically) so it makes sense to rate these devices in Amps.
A USB PD enabled device however, can provide different voltages (5V-20V) based on the capacity and charging profile of your device. It can also vary its current similar to a standard USB device. As a result, it makes more sense to measure the charging capability of a USB PD device in Watts vs. Amps.
Rating the device in Watts also helps better correlate with power supplies of larger devices such as laptops.