The USB Implementers Forum, the alliance that manages the USB specification, recently announced the latest update to USB, specifically USB Power Delivery. With bidirectional power delivery of up to 240W, this update is the latest in a string of advancements, building the foundations of a unified charging system for the future.
A decade ago, USB charging during data transfer was just a formality. Devices would need a dedicated charger and a cable that solely transfers power.
Even then, it would take hours, and you couldn’t even think about charging larger devices through this method. Today, phones, laptops, mini-robots are a small portion of the plethora of devices that use USB as the sole power charging method. Most modern notebooks can be charged using a USB port, while some gaming machines also flirt with the USB method.
A huge factor in the advancement of USB as a power delivery method is the USB-Type C connector system. Released in 2013, the specification is the closest thing to a unified port system that we’ve got.
While there is still progress to be made, the fact that protocols such as HDMI and DisplayPort are now common over USB-C gives us hope that we could do away with a huge number of cables and adapters in the future.
Before we jump into the details of this update, let’s first talk a bit about USB-C, what it is and how it is different from its predecessors.
Table of Contents
What is USB-C?
If you don’t know anything about USB standards and are used to just plugging in the cable that comes along with your device, understanding all the new specifications is impossible! So let’s break it down! To most people, USB-C is just the latest shape of USB ports and pins! The duckface-shaped port you are already familiar with is the USB-A specification, and while USB-A is the most recognizable shape of a USB port/cable, it is slowly being replaced by the new USB-C.
USB-C ports are smaller, oval-shaped, and most importantly, they are flippable. You don’t need to check which side goes up; just stick it in. In addition, USB-C is also bi-directional. Older USB-A cables usually had the duck-face-shaped pin at one end and a smaller delivery pin at the other, which you would insert into your phone or anything else you want to charge or connect with.
USB-C cables, however, have the same shape at both ends, and it does not matter which side goes where( unless you have a USB-A to C converter cable, which is common in phone chargers). Data and power can move in both directions across the cable. USB-C ports and cables are also capable of supporting much larger data and power transfer rates.
All these protocols and specifications are maintained by the USB-Implementers Forum (USB-IF). This forum counts more than 600 companies as its members, with big names such as Apple, Intel, HP, and Texas Instruments. Once a new update or specification is announced, the USB-IF shares it with manufacturers, along with the standards that these manufacturers have to maintain. The fact that the USB-IF has unified such huge names is the key to its success and why it has become so popular.
While USB-C can transfer data speeds of up to 40Gbps currently, most USB-C ports will not be anywhere near that. The reason for this is that, in its true form, USB-C only provides the channel across which data and power are transferred. It is simply infrastructure for delivering data and power. Just because the infrastructure is there does not mean your devices have the capability to use it.
What is a USB Protocol?
How quickly data and power is being transferred depends on the capabilities of the devices you are using as well. More specifically, what protocols these devices are capable of using. Protocol is a particular set of instructions to communicate with the data transfer port. So if your device has a particular protocol available, only then can you use USB-C to benefit from that protocol’s ability. For example, if your device can deliver the HDMI protocol, you can use USB-C to deliver it.
Are all USB-C ports equally capable?
While USB’s ability definitely limits the data and transfer capability, it is also possible that your devices limit the specifications’ ability. For example, currently, USB-C is limited to transferring data rates of up to 40Gbps, but most devices won’t get to that limit. Some might deliver 10Gbps, some even less.
USB-C was released in 2014, right around the same time the USB 3.2 update came along. In the start, USB-C could get up to 10Gbps, so it could support the USB 3.2 specifications. Things have improved very quickly since then, and the latest Thunderbolt 4 specification (controlled by Intel), which also uses USB-C, can deliver up to 40Gbps.
What are USB 2.0, 3.0, 3.2 etc.?
USB 2.0 to USB 4.0, are all USB specification updates. While USB-C connecter system is a hardware infrastructure, an update includes a lot more than the hardware. Like USB-4 released in 2019, a new update can include newer protocols, newer standards for manufactures, better capabilities, improved hardware, and a lot more. Basically, every time the USB-IF wants to incorporate all the R & D it has done in the past years, it releases a new major update. Then, all devices that have this new update in them are given the name and number. So a USB 3.2 port is basically a USB port that incorporates all the updates released in USB 3.2. The USB 4.0 update, based on the Thunderbolt 4 specification, is the first update that solely relies on USB-C type.
USB-C Power Delivery
While we have discussed data speeds, USB-C also improves vastly on Power Delivery. This is because it uses an updated Power Delivery technology and certain protocols that help it. As shown in the visual taken from a presentation given in the USB-IF, power delivery over USB has increased in the past two decades. USB 2.0, the first major USB update, could deliver up to 2.5W. Over the years, this went up to 100W, and with the new update that we’ll discuss later, this can get up to 240W!
The increase in power delivery has been due to new protocols such as the USB Power Delivery Protocol or the Alternate Mode Protocol, which better manage the data and power flowing through them.
The Latest USB Power Delivery Update
The latest USB update was announced at the start of this year, and it primarily deals with Power Delivery. It has the following features.
Increased Power Levels
Previously, USB-C could deliver up to 5A of current at 20V. The latest update sees the current limit intact, but higher voltage levels are added. This is probably because the increasing current has a larger effect on losses than increases voltage. So going beyond five amps in a USB-C cable would either mean losing a small amount of data speed or just skyrocketing the price of USB-C cables. The new voltage levels are 28V, 36V, and 48V, corresponding to 140W, 180W, and 240W.
Adjustable Voltage Supply Mode
The device that is being powered can now request different power levels, ranging from 15V to one of the three maximum limits. This is introduced through new protocols that allow for a more responsive power transfer. Devices can request power anywhere between the limits with up to a resolution of 100mV.
Power direction has always been fixed, but now both the peripheral and the host can deliver power. This is accomplished through better protocols that allow the device to communicate its needs. Initially, we thought that using advanced circuit protection, the device with the larger power rating will automatically transfer power to the lower one. Still, lately, there has been talking on tech forums that this technique would require transformers and hence power losses, so the devices will communicate beforehand, and then power transfer will happen. It’ll be clear once the first devices with this update rollout.
Power Management across Peripherals
There are some hubs on the market, like this one, which can manage power between peripherals, ensuring power delivery to the largest device does not suck up the entire range. Perhaps, the USB-IF is using tech like these, but to do that through communication protocols in every USB port is impressive. However, the forum has hinted that there can be optional hub communication between the PC and the ports to set power limits beforehand.
These power delivery updates are especially interesting for laptop users who prefer larger notebooks. Most USB docks right now offer up to 100W of power delivery, which is sufficient for many smaller machines, but 13” or higher notebooks require more power. Getting up to 240W could mean that users can forget about dedicated chargers and simply use USB-C cables.
Gaming laptops are a whole other thing, though. These machines are quite power-hungry, and while 240W is still a huge leap, you won’t get rid of traditional chargers that easily.
According to Brad Saunders of the USB Promoters Group, the latest update will roll out in the second half of this year. While some technical questions can only be answered once we have seen the tech and reviewed it, there is no denying that this has to be one of the most significant leaps in power delivery capabilities that USB has ever made.