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USB Power Delivery explained: What you need to know about ubiquitous charging
Fast charging is a godsend when our gadgets run low on juice. However, there are numerous fast charging standards in existence today, making it difficult to pick the right charger. Furthermore, while most gadgets historically shipped with an adapter in the box, many manufacturers are now asking you to bring your own. Luckily, USB Power Delivery (USB PD) is a universal charging specification that allows you to sidestep the fragmented charger market altogether.
Here’s everything that you need to know about USB Power Delivery and what it means for your gadgets.
When 100% is not 100%: How long does it really take to fully charge your phone?
USB Power Delivery – what you need to know
USB Power Delivery is a common fast-charging standard that can be implemented in all USB-powered gadgets. USB PD has actually been around since 2012, around the same time that the USB-C port was unveiled. Prior to that, the only universal option was the (significantly slower) USB Battery Charging specification.
Modern USB-C ports are complicated beasts and actually support several levels of charging. And that’s before manufacturers add proprietary capabilities on top of that.
Read more: Why USB-C is still a mess
To start with, all USB ports support a very basic level of charging at just 5V and up to 500mA, with more modern ports supporting 5V and 900mA of current. This is based on legacy support and is very slow to charge all but the most low-power gadgets. USB-C ports can be configured with 5V 1.5A and 3A for up to 15W of power, which is a bit quicker but still rather slow compared to other fast-charging standards.
USB Power Delivery is much more powerful, supporting up to 240W of power to charge up even the most demanding gadgets such as laptops. It’s also safer, as gadgets and chargers communicate with each other over the USB cable to confirm the optimal charging power level. This handshaking approach supports voltage steps at 5V, 9V, 15V, 20V, and beyond for power outputs ranging from 0.5W to 240W.
The new USB Power Delivery Programmable Power Supply (USB PD PPS) standard supports configurable voltages too, enabling more optimal charging. If two devices fail to communicate a suitable power rule, USB Power Delivery will default to the next power option supported by the relevant USB protocol, such as USB-C 1.5A.
The latest USB PD revision can deliver up to 240W of power for demanding gadgets like laptops.
USB Power Delivery is now commonly used to fast-charge smartphones, laptops, and other gadgets. Examples include the entire line-up of Google Pixel handsets, Samsung’s Galaxy S smartphone range, and Apple’s iPhone and MacBooks.
A huge range of other smartphones support the standard too, often in addition to their faster proprietary standards. Many OnePlus smartphones, for example, support between 18 to 27W charging over USB PD. That’s in addition to the company’s own Warp Charge technology.
USB Power Delivery versions compared
With USB Power Delivery now into its third revision, the standard is broken down into devices with slightly different capabilities. Although modern versions of the standard are backward compatible with older gadgets and chargers.
USB PD 1.0 was a little more basic than the modern version. It simply offered six fixed power profiles for different device categories. This version supports 10W (5V, 2A), 18W (12V, 1.5A), 36W (12V, 3A), 60W (12V, 5A), 60W (20V, 3A), and 100W (20V, 5A) of power exclusively. That’s OK, but not exactly flexible for a wide range of gadgets, including small smartphone batteries that prefer lower voltage charging.
The more modern USB Power Delivery 2.0 and 3.0 variations drop fixed profiles in favor of more flexible power rules. These rules keep fixed voltage brackets but allow for a wider range of negotiated current levels. The end result is a standard that’s better suited to a wide range of devices. USB Power Delivery 3.0 also extends the communication protocol to support features like battery condition, enhanced security, and fast role swapping.
|USB PD Power Range||Fixed Voltage||Current Range||Example devices|
|USB PD Power Range|
0.5 - 15W
0.1 - 3.0A
Headphones, small USB accessories
|USB PD Power Range|
15 - 27W
1.67 - 3.0A
Smartphones, cameras, drones
|USB PD Power Range|
27 - 45W
1.8 - 3.0A
Tablets, small laptops
|USB PD Power Range|
45 - 100W
2.25 - 3.0A
3.0 - 5.0A only with rated cable
Large laptops, displays
The majority of modern smartphones make use of the USB Power Delivery 2.0 and 3.0 specification. 18W of power is quite typical for smartphones, while today’s laptops pull around 65 to 100W. The latest 3.1 revision will eventually bring about devices with 140W, 180W, and 240W charging.
USB PD Programmable Power Supply explained
Despite improvements with USB Power Delivery 2.0 and 3.0, they’re still not entirely suited to the flexible requirements of very fast charging. Battery charging speed is sensitive to specific voltages and this changes depending on the battery’s current charge. The 5V, 9V, 15V, and 20V set voltages in the standard specification aren’t ideal for optimal fast charging.
The USB Power Delivery 3.0 revision released in 2018 also introduced the Programmable Power Supply protocol into the standard. USB PD PSS is much more flexible, allowing for configurable voltage levels at very small 20mV granular increments. Combined with device-to-charger communication and voltage-control charging algorithms, the ideal voltage can be negotiated and even changed during charging. This makes USB PD PPS far better suited to fast-charging than the standard USB PD protocol.
As the newer part of the standard, support for USB PD PPS is limited to just a handful of gadgets and charging accessories in 2021. Support is starting to grow, particularly in the charger market, but the latest specification is leading to a few headaches for consumers. For example, Samsung’s Galaxy S22 series can only be fast-charged at their full 45W of power using USB PD PPS chargers. Otherwise, consumers are stuck with a slower 18W when using standard USB PD.
See also: What is Qualcomm Quick Charge?
How fast is USB PD charging?
Given the variable nature of USB PD charging and the wide range of battery capacities, it’s impossible to give a precise speed for the standard. Very broadly speaking though, large battery capacity phones charge to full using 18W USB Power Delivery in a little over an hour. Large capacity laptops using 65W charging can take between an hour or two.
Unlike laptops, smartphones generally don’t like to use high voltages to charge their batteries. Typically, smartphone fast charging uses 5V or 9V and high currents to charge up the battery. For example, OnePlus’ 65W charging tech uses 10V and 6.5A charging and Huawei’s 40W option uses a similar 10V and 4A. Keep in mind that both of these are proprietary technologies.
9V is the closest USB PD voltage setting, which is capped at a much slower 27W of maximum power. Most USB Power Delivery smartphones we’ve seen don’t actually use the full 3A either, capping their power at 18-20W.
Our testing: The Pixel 6 charges much slower than Google implied
Proprietary technologies are pushing the boundaries even further, with Oppo teasing 240W capabilities and Xiaomi already offering 120W charging. That said, there are diminishing returns in terms of power consumption versus charge time anyway. Around 40W is plenty to charge a smartphone super fast.
Consumer convenience and the ecological argument
While charging speed is an important factor in the design of USB Power Delivery, and PPS in particular, it’s not the primary design goal. USB PD was created as a single standard to power a wide range of USB gadgets. Thereby reducing the need for proprietary ports, connectors, and plugs.
First and foremost, this should make it much easier for consumers to just plug and charge. E-waste from old chargers and cable is a growing problem, not just for landfills but as a drain on precious metals and other finite resources. There are strong environmental reasons for consumers and manufacturers to embrace a unified charging technology like USB Power Delivery.
Smartphone brands removing charging bricks from the box may be a controversial decision today, particularly as consumers don’t necessarily own a compatible USB PD PPS charger. But in the long term, we might not pay a second thought to the lack of bundled chargers as all our gadgets charge quickly from plugs we already own. That’s the theory anyway.
Need some suggestions? Best multi-port USB wall chargers