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What is USB PD (Power Delivery)?
We provide a detailed explanation of what USB PD (Power Delivery) is. We also offer a functional overview and basic information, including the PD standard USB PD3.0, the latest PD standard USB PD3.1, and the current state of USB technology.
目次
Since announcing our USB PD products at Techno-Frontier 2018, we have received many questions asking, "What is USB PD (Power Delivery)?" Therefore, we provide an explanation on this page. This device, which enables multi-device charging, automatically adjusts power according to the connected device, making it extremely convenient.
At the previous Techno-Frontier exhibition, we showcased two new USB PD (Power Delivery) products. We sincerely appreciate the very positive feedback from visitors. In response to recent customer demand, UNIFIVE has developed two USB PDProducts rated at 40W and 60W, and has since expanded the lineup to include a 65W model.
What is USB PD (Power Delivery)?
The Appeal of Next-Generation USB PD: Enabling Data Transfer and High-Power Supply
USB PD (USB Power Delivery) is a new USB technology that enables both data transfer and high-power delivery through a single cable. Compared to conventional USB, USB PD-compatible AC/DC Power Adapter have evolved to supply both power and data simultaneously via a USB Type-C cable, maximizing USB performance. This technology enables significantly higher power delivery than previous USB charging methods, making it possible to charge not only smartphones and tablets but also high-power devices such as laptops.
Below is a summary of USB PD features:
Compared to conventional USB 1.1 (2.5W), USB 3.0 (4.5W), and USB-BC1.2 (7.5W), USB PD can supply up to 100W of power.
- Eliminates fixed roles of power source and sink, allowing power supply and reception to be swapped (Role Swap). For example, a PC charging an external battery can, through role swap, be charged by the external battery instead (when using a Type-C cable).
- Enables power optimization across multiple external devices.
Automatically adjusts power according to the connected device.
Current USB Environment
Today, USB ports can be found everywhere - not only in cars, but also on public buses and airplanes. It has also become common to obtain power from a computer's USB port. USB has truly become a ubiquitous charging interface for small devices such as smartphones.
Traditional USB ports were primarily used for data transfer via USB drivers. However, users gradually began using them not only for data communication but also as a power source for charging and other purposes.
Safe and Reliable USB PD with USB PD 3.0
USB-PD 3.0, the latest standard established by the USB-IF (Implementers Forum), aims to eliminate inferior cables and substandard Products from the market to ensure safe and reliable use of USB PD.
Compared to version 2.0, USB-PD 3.0 enables faster role swaps, reducing the risk of data corruption even if power supply is temporarily interrupted.
It also introduces a mutual authentication function called C-AUTH (USB Type-C Authentication), which allows devices to verify whether connected devices or cables are trustworthy Products, and block functionality if issues are detected.
*Click here for an explanation of USB Type-C
USB PD 3.1: Evolution to Up to 240W Power Delivery
In today's market, USB PD 3.0 is mainstream; however, on May 26, 2021, the USB-IF (Implementers Forum) announced the new USB Power Delivery (USB PD) Revision 3.1 specification.
This major update enables power delivery of up to 240W via USB Type-C® cables and connectors. As explained above, previous USB PD solutions were limited to 100W using 20V with a rated 5A USB Type-C cable.
Accordingly, the USB Type-C specification was updated to Release 2.1, defining requirements for 240W cables. Updates to the USB PD protocol and power definitions now allow USB PD to be applied to many devices for which 100W was previously insufficient.
The new USB PD architecture defines significantly stricter power negotiation protocols to ensure safe access to and use of this higher power capability. Safety requirements for Products using 100-240W are stricter than those for low-power Products and are determined by safety specifications based on regulations in each country where the Products are sold.
With the new features of USB Power Delivery 3.1, high-power Products such as large laptops may transition from conventional power connectors to USB Type-C.
Three New Fixed Voltage Options: High Power Output with EPR (Extended Power Range)
A key feature of the USB PD 3.1 specification is the addition of three selectable fixed voltage levels. In addition to the existing SPR PDO and SPR APDO specifications of 5V, 9V, 15V, and 20V, new fixed voltages of 28V (over 100W), 36V (over 140W), and 48V (over 240W) are now available. With EPR (Extended Power Range), a major new feature of USB PD 3.1, power delivery above 20V is now possible. EPR adds fixed voltages of 28V, 36V, and 48V, supporting power delivery exceeding 100W, 140W, and 180W respectively.
EPR Mode: Safety Protocol for High-Power Delivery
EPR mode is a communication protocol designed for safely supplying high power. Before entering EPR mode, the source (power side) and sink (device side) confirm each other's capabilities and establish agreement for safe power delivery.
Below is a simplified table summarizing the history and specifications leading up to USB 3.1.
| Year Announced | 2010 | 2012 | 2014 | 2015 | 2017 | 2021 |
|---|---|---|---|---|---|---|
| USB Standard | BC1.2 | PD1.0 | PD2.0 | PD3.0 | PD3.0 PPS | PD3.1 |
| USB Connector | Type-A | Type-A, Type-B | Type-C | Type-C | Type-C | Type-C |
The Fastest and Most Optimal Charging Experience with USB PD
USB PD offers more than just high-power delivery. USB Type-C includes a dedicated signal line called CC (Configuration Channel). When a USB Power Delivery-compatible device is connected, it automatically detects the optimal power for the device and initiates rapid charging.
Evolution of Type-C Cables: Improved Safety with EPR Support
With the expansion of USB PD 3.1, the USB Type-C cable specification has also been updated to version 2.1. EPR-compatible cables include an E-Marker chip indicating support for 50V and 5A, improving safety and reliability during high-power delivery.
Higher Efficiency and Miniaturization with GaN Technology
GaN (Gallium Nitride) is gaining attention as a next-generation semiconductor material. Power devices using GaN feature lower power loss and faster switching speeds compared to conventional silicon-based devices. By adopting GaN technology in USB PD 3.1 power supplies, both high efficiency and compact size can be achieved.
The History of USB PD in Chronological Order
Before USB PD: Low-Power Charging and Fragmented Standards (1996-2012)
- 1996: USB 1.0 introduced. Initially intended for data transfer, it could supply 5V/100mA, which was insufficient for charging.
- 2000: USB 2.0 introduced. Power increased to 5V/500mA, enabling mobile phone charging.
- 2007: USB BC 1.1 introduced. Fixed at 5V with up to 1.5A (7.5W).
- 2010: USB BC 1.2 introduced with more robust charging specifications.
Birth and Evolution of USB PD: High Power and Bi-Directional Supply (2012-2021)
- 2012: USB PD 1.0 introduced, enabling up to 100W (20V/5A) for large devices such as laptops.
- 2014: USB PD 2.0 introduced PDO (Power Data Object) and USB Type-C connectors.
- 2015: USB PD 3.0 introduced PPS (Programmable Power Supply), improving charging efficiency and safety.
USB PD 3.1 and GaN Technology: Toward Even Higher Power and Efficiency (2021-)
- 2021: USB PD 3.1 introduced EPR, enabling up to 240W (48V/5A). Advances in GaN technology further improved efficiency and miniaturization.
The Future of USB PD: Powering All Devices
USB PD is expected to expand beyond mobile devices such as laptops, smartphones, and tablets to home appliances, industrial equipment, and many other fields. With the evolution of USB PD 3.1 and GaN technology, a future where all devices are charged via USB Type-C may soon become reality.
UNIFIVE offers a wide lineup of next-generation compact AC/DC Power Adapter incorporating GaN in the latest PD solutions.
We also support custom orders starting from small lots and provide flexible proposals. For samples or other inquiries, please feel free to contact our sales team.