What is USB Power Delivery?

USB Power Delivery (USB PD) enables safe, flexible USB charging up to 100W over a full-featured USB-C cable (support for up to 10 Gbps data transfer and 100W Power Delivery) when connected to a full-featured USB-C or Thunderbolt 3 / 4 port.

As an added benefit, USB PD enables consumers to transition to a single type of charger for laptops, phones, tablets, and devices with a USB-C or Thunderbolt 3 / 4 connection.

But Wait, There's More

There's more to Power Delivery than just more power. Suppose your device doesn't need 100W.

Devices that support USB PD will actually negotiate with the system for their required power levels allowing the device to pull the appropriate charge. The USB charging capability can even adjust as the needs of the peripheral change.

The direction of the power flow is no longer one way, either. Now either the device or the peripheral can supply the charge.

Put in Practice

To put Power Delivery in practical parlance, let’s take a look at how different wattages charge a laptop. But first, we need to clear up some confusion. Your computer’s maximum charging rate isn’t your computer’s only charging rate.

Assuming you’re charging through USB-C (because, why would you be reading this if you weren’t?), you can power up with more or less wattage than your computer’s native charger prescribes. In fact, Apple sells a 61W USB-C Power Adapter and a 96W USB-C Power Adapter for their Macbooks.

To demonstrate, we charged a 14-inch Macbook M1 Pro with a Plugable TBT3-UDZ (96W charging) and a Plugable UD-6950PDZ (60W charging). This is what we found:

It’s worth noting that when we ran these tests, the computer wasn’t under a heavy workload. The more you use your computer while it’s charging, the longer it will take to top off the battery. And, if you’re working on a power-intensive project, like video editing, you may find yourself drawing more power than you’re replacing when using a wattage lower than your laptop spec calls for.

To sum it up, when sitting up your desk, consider a hub or docking station with a simple one plug solution. And if you’re going with that option, consider your daily work habits. How fast do you need to charge? Just remember, you can safely charge your laptop with a standards-compliant USB-C charger or docking station that provides different wattage than what your system manufacturer provided (but you can usually save a little money with a lower wattage option).

Current Events

Charging small electronics through USB isn't new. Although USB originally focused on data delivery, even early generations of USB were capable of limited charging. USB 1.0 managed to deliver 0.5W, while USB 2.0 boasted 2.5W. (Learn more about the history of USB and the different Thunderbolt and USB Standards.)

It wasn't until the introduction of the Battery Charging (BC) Specification 1.2 that USB-C connectors became a viable power supply. And even then you could only expect 7.5W through a feature referred to as Charging Downstream Port (CDP).

Things got interesting in the world of USB-C Power with the introduction of USB PD, allowing users with a full-featured USB Type C cable (and supported USB-C port) to draw 100W of power. Suddenly phones weren't the only thing getting charged.

100W Is Nice, but 240W Would Be Nicer

100W seems like a lot, surely this is the end of the road, right? Not so fast, Sparky. Even at 100W, larger devices—think gaming laptops—can't get their fill.

In 2021, USB PD Revision 3.1 Extended Power Range (EPR) (USB 3.1) changed the flow of power again with higher wattage. Now, users with equipment that supports EPR can pull in an impressive 240W. That's enough to slake even the most power-thirsty of laptops. (Learn more about USB ERP)

This is a pretty high-level examination of USB Power Delivery, check out USB.org to learn more about charging standards.

Questions on connections, or comments about anything else? Comment below, or contact us at support@plugable.com.

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Industry News, Thunderbolt™ 3, Thunderbolt™ 4, USB, USB Power Delivery, USB-C

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