USB Power Delivery (USB-PD)
USB Power Delivery (USB-PD) is a fast-charging protocol introduced by the USB Implementers Forum (USB-IF) in 2012 to enhance the power delivery capabilities of USB connections. Unlike earlier standards, which provided limited power output (5V/0.5A for USB 2.0), USB-PD supports power delivery of up to 100W (20V/5A) over a single cable. This capability allows USB connections to charge a wider range of devices, from smartphones to laptops and even monitors, while simultaneously supporting high-speed data transfer.
https://en.wikipedia.org/wiki/USB_hardware
A key feature of USB Power Delivery is its dynamic power management. The protocol allows devices to negotiate the required power level in real time, optimizing charging efficiency and reducing energy waste. This flexibility is particularly beneficial for devices with varying power requirements, such as smartphones that fast charge at higher voltages and then taper off to avoid overheating. The integration of USB Type-C connectors with USB-PD has further enhanced its adoption, thanks to the connector's reversible design and robust power-handling capabilities.
https://www.usb.org/sites/default/files/usb_pd_r3_1200.pdf
USB Power Delivery has been widely adopted across consumer electronics, enabling features like rapid charging for laptops and support for dual-role devices that can both supply and consume power. For example, a laptop can charge a smartphone while simultaneously receiving power from an external charger. This universal approach to power delivery has simplified device connectivity, reducing the need for proprietary chargers and cables, and has become a key feature in modern USB standards like USB4.