What is the differences between USB Type-C and USB Power Delivery (PD)?
USB Type-C and USB-PD are essential technologies for modern connectivity. The main distinction between the two is that USB-C is a reversible USB connector with a small form factor, while USB-PD is a power delivery protocol allowing for up to 100W power delivery.
Understanding these technologies requires examining their USB-IF specifications, which are detailed in the following sections.
What is USB Type-C?
Type-C connectors are versatile, reversible connectors that support faster data transfer rates and are capable of delivering more power. They are becoming the standard charging port on newer devices, replacing the older USB Type-A and Type-B ports.
Benefits of USB Type-C:
- The USB Type-C connector is smaller in size compared to the Type-A and Type-B connectors that came before it.
- USB-C cable connectors can transfer data at speeds of up to 10 Gbps, making them faster than older USB Type-A and Type-B connectors.
- The connector is reversible and has a height of only 2.4 mm.
- The product is compliant with USB Power Delivery 2.0 and can provide up to 100 W of power.
USB Type-C Specification
The USB-C Cable and Connector Specification outlines a new set of standards for receptacles, plugs, cables, and detection mechanisms that are compatible with existing USB interfaces. It specifies the performance requirements of Type-C receptacles, plugs, and cable assemblies, as well as USB Type-C to legacy cable assemblies for backward compatibility with older USB designs.
The USB Power Delivery standard, designed for the USB-C connector, is included in this specification. By default, USB Type-C ports can provide up to 5V and 3A of power without Power Delivery. The USB-C specification also includes a standardized method for supporting Alternate Modes, allowing the connector to be used for specific docking applications. It's important to note that this does not extend the USB data protocol. The USB-C port is compatible with USB 2.0, USB 3.1 Gen1, and USB 3.1 Gen2 data transfer.
What is USB-C PD?
USB Power Delivery (USB-PD) is a standard that enables devices to provide increased power and quicker charging rates through USB-C cables. Using USB-PD allows for faster device charging and the powering of larger devices.
Benefits of USB-PD:
- USB-PD enables quicker charging speeds and increased power delivery compared to traditional USB charging methods.
- USB-PD is a versatile charging technology that can accommodate various charging requirements.
- USB-C PD is compatible with a wide range of devices and chargers.
USB-PD 2.0 Specification
The USB-PD specification outlines the power delivery system for all components of a USB system, including hosts, devices, hubs, chargers, and cables. It covers architecture, protocols, power supply behavior, connectors, and cabling needed to handle power delivery over USB Type-C ports up to 100W.
The USB-PD 1.0 specification used binary frequency shift keying (BFSK) signaling for older USB ports, while USB-PD 2.0 uses biph + ase mark coding (BMC) signaling for power delivery through USB Type-C connectors. This specification is meant to be fully compatible with and expand upon the current USB infrastructure. It's important to understand that USB Power Delivery operates independently from existing USB bus mechanisms. The figure below shows a comparison of power capability between legacy USB ports and USB Type-C ports with power delivery.
Figure 1 - USB Power Delivery VBUS Current/VBUS Voltage
Is the USB Type-C port compatible with only USB and standard 5 V on VBUS?
USB-C ports are compatible with USB-only devices and support standard 5-V VBUS.
The USB Type-C host can provide 5 V with either 3 A or 1.5 A, and indicates its current capabilities through pull-up resistors on both CC lines.
Devices utilizing USB C must include a 5.1K pull-down resistor Rd on the CC line for devices with only a USB Type-C connection. For devices with a Type-C receptacle, Rd should be advertised on both CC1 and CC2 lines.
What is the process for USB-C devices to manage VBUS voltages that are not 5 V?
For a device that requires a voltage other than 5 V, it must be able to communicate with USB PD. The USB PD source sends its power profiles to the device in the source capabilities. The device then selects one of the advertised power profiles based on its sink capabilities. Once a contract is established, the host delivers the requested voltage on VBUS.
Additionally, you can easily access and download the USB Type C and PD specifications directly from the official USB-IF website.
Translation from Japanese: USB Type-CとUSB-PDの違い - KBA204033 - Community Translated (JA)
Source: KBA204033