USB Power Delivery and Data Transfer Standards

This article lists the details of USB power delivery and data transfer standards and provides the logos and markings for ease of identification.

It is important to note that not every manufacturer uses the proper USB marks on each port, like in our featured photo above. As there are so many different USB standards, we could not remember the specifications for all our devices, and it would help if there were markings for every USB port. This is, so users will know if the port on the device is compatible with other devices and intended usage.

Table 1: USB Power Delivery

USB PD3.0 was released on 8 Jan 2018 and introduced the “Certified USB Fast Charger” logo for chargers with the Programmable Power Supply (PPS) protocol. The PPS helps to renegotiate non-standard currents and voltages between the device and the charger (Ref: Belkin). This means you can use the charger for various devices without other adapters.

USB PD 3.1 was released on 24 May 2021 on the USB-IF website. Due to the high voltage requirement, it must be used with supporting cable with the EPR marking that support up to 5A. The USB cables rated at 5A are thicker than the 3A cables.

• Support Adjustable Voltage Supply (AVS), from 15 to 48V in 0.1V steps
• Support Extended Power Range(EPR), with variable power up from 15V to 48V/5A (240W max)

(Ref: Wikipedia – USB hardware)

Without the USB Power Delivery, a USB connection provides a lower power as follows:

Read also:
Mobile Phone and Tablet Charging Specs

Table 1a: USB Power Supply Without PD

Table 2: USB Transfer Speed Table

Source: Wikipedia – USB

USB Type-C™ and USB-C™ are trademarks of USB Implementers Forum.

Table 3: Thunderbolt

Thunderbolt 3 and 4 support up to 100W charging speed (PD 3.0) and 15W for computer peripherals. Whereas Thunderbolt 1 and 2 are not

Thunderbolt is the brand name of a hardware interface for connecting external peripherals to a computer. Intel has developed it in collaboration with Apple.

Note that not all USB Type-C support Thunderbolt unless explicitly stated by the device manufacturer.

For backwards compatibility, some older devices, such as Surface Pro and high-end workstations notebook, support the older Thunderbolt 1 or 2 ports. They are also helpful for connecting to external HDMI and 4K displays.

USB-Type C Port for Thunderbolt 3 and 4Source: Wikipedia – Thunderbolt

Notes

The read/write speed of a typical 7,200 rpm HDD is 80-160 MB/s, SSD starts at 550 MB/s, and up to 5,000-7,000 MB/s, such as the Samsung 980 PRO PCle 4.0 NVMe M.2 SSD. Based on the above table, it requires at least a USB 4 Gen 3×2 to fully utilize the high read and write speed of the fastest SSD in the market.

USB-C Advantages

The USB-C or USB Type C is the preferred data and electrical power connector. It has high power delivery and data transfer rate and has replaced the micro-USB on most, if not all, consumer electronics device and gadgets. It is both surprising and frustrating that iPhone Pro 12 is the only high-end device in the market that has yet to adopt this standard connector.

USB-C should be an essential design requirement that everyone should look out for when deciding on their next purchase. Users will only need to have one type of cable to support all devices for both data and power transfer. The most important reason is that having USB-C means your device is “future-proof”. So if your device still did not have USB-C in 2021, it is technically classified as outdated.

Besides power delivery high data transfer rate, USB-C does not have any up or down orientation requirements like the older micro-USB standard. It is easier to plug in even in the dark as long you can locate the port by touch.

In terms of size, USB-C is slightly larger than the micro-USB Connector. However, it does not appear to affect the size of the peripheral device design. The USB-C might feel too big unless a 5mm thin phone comes along.

There may be a need to focus on safety as the power delivery output increases. The “USB” cable no longer delivers low DC power for data and charges the mobile phone. At 240W, these cables should be treated with care like any existing notebook power cables and adapters. Never trade safety for cheap and unqualified design.

New USB-C PD Review 3.1

USB-C will only get better. In May 2021, USB-IF published the details of a new USB PD Revision 3.1 specification that increases the PD (Power Delivery) via USB-C (aka USB Type-C) from 100W (20V 5A) to 240W (48V 5A). USB-IF published the USB-C Cable and Connector Design Specification Revision 2.1, which include the reference design and guide for implementation.

The new standard is called the Extended Power Range (EPR), which manufacturers would need to comply with producing new cables that are EPR-certified to deliver 240W (48V 5A) power supply.

So what does this mean for the consumers like us?

1. USB-C connectors could power up almost all power notebooks, including high-end gaming laptops with powerful discrete graphics cards.
2. One standardized, universal connector (jack) for all notebooks and laptops. There will be no need to worry about power adapters from different brands with different power ratings. Everyone can share the same type of cable.

One point to note is that USB-C design revision 2.1 (EPR) deals with power delivery only, whereas the data transfer rate for USB-C connectors and cables is currently using USB 3 standard.

In 2017, USB 3.2 standard was explicitly released for USB-C, and the current highest transfer speed is USB 3.2 Gen 2×2 – SuperSpeed+, new 20 gigabits per second (Gbit/s) data rate over 2 lanes using 128b/132b encoding (effective 2,424 MB/s).

USB 4.0 announced in Aug 2019, could potentially push the transfer speed up to 40 Gbps!

Will the “Power Brick” Finally Disappear?

It is already happening, especially with the 200W GaN Chargers already in the market. These pocket-sized and lightweight chargers only deliver up to 100W per USB-C port at this time of writing, and we expect higher power ratings in the near future.

In June 2021, Xiaomi has announced the patented Xiaomi Hypercharge that can deliver up to 200W wired and 120W wireless. We should be expecting 240W chargers coming soon next few years. One of our concerns is related to safety, such as the USB wire design and the connector to support 240W of power.

All existing USB-C PD Chargers have built-in AC/DC converters since the mobile devices use DC current.

If the USB-C can delivery 240W safely to laptops, then all the different brands of laptop should be able to use the same USB-C cable and charger in the future.