What is the difference between USB Type-C and USB Power Delivery (USB-PD)?
The fundamental difference between USB Type-C and USB-PD is that USB Type-C is a new reversible USB connector with a small form factor, whereas USB-PD is a power delivery protocol that supports power delivery up to 100W.
The following sections explain the USB IF specifications for the USB Type-C and USB-PD.
USB Type – C Specification
The USB Type-C Cable and Connector Specification defines a new receptacle, plug, cable, and detection mechanisms that are compatible with the existing USB interface. The specification covers various aspects such as the performance requirements of Type-C receptacles, plugs, and cable assemblies. It defines USB Type-C to legacy cable assemblies for compatibility with legacy USB designs. It also describes USB-PD, optimized for the USB Type-C connector. The USB Type-C ports by default can support the power of 5 V up to 3A without power delivery. The USB Type-C Cable and Connector Specification defines a standardized mechanism that supports Alternate Modes, such as repurposing the connector for docking-specific applications. Note that it is not an extension to the USB data protocol. The USB Type-C port can support USB 2.0, USB 3.1 Gen1, and USB 3.1 Gen2 data.
USB-PD 2.0 Specification
The USB-PD specification defines a power delivery system covering all elements of a USB system including hosts, devices, hubs, chargers, and cable assemblies. This specification describes the architecture, protocols, power supply behavior, connectors, and cabling required for managing power delivery over USB Type-C port at up to 100W. The USB-PD 1.0 specification defined a power delivery protocol using binary frequency shift keying (BFSK) signaling for legacy USB ports. The USB-PD 2.0 specification defines power delivery over USB Type-C connectors, which is based on biphase mark coding (BMC) signaling. This specification is intended to be fully compatible and extend the existing USB infrastructure. It is worthwhile to note that the USB Power Delivery is designed to operate independent of the existing USB bus defined mechanisms. The following figure compares the power capability of the legacy USB ports with those of the USB Type-C port with power delivery.
You can download the USB Type C and PD specifications from the USB-IF website.