An Engineer's Guide to USB Type-C and Power Delivery in 2024
An Engineer's Guide to USB Typе-С (2024)
I break down the evolution of USB Type-C and USB Power Delivery, showing how they now support up to 240W of power and 80Gbps of data. We explore essential concepts like data roles, power roles, and alternate modes such as DisplayPort and Thunderbolt. This guide helps you understand system requirements and design challenges for modern applications ranging from laptops to industrial tools.
With USB Power Delivery, you can now transmit up to 240W of power and up to 80Gbps of data at the same time.
- mtabini
Bit of self-promotion: I spent the last year or so designing an open-source USB-PD protocol analyzer[1], and the complexity of the protocol can be mind-boggling. Most of the time, the communication between source and sink is really straightforward, but it can get amazingly complicated when both devices are dual-role or come from the same vendor[2].
As messy as it is, however, it's also a very useful protocol that allows even small players to take advantage of the same economies of scale that large companies can take advantage of. Pity that the communication often requires dedicated chips, though thankfully those are relatively inexpensive. I was able to get an RP2350 (the same MCU that's in the Raspberry Pi Pico 2) to interface directly with USB-PD, but they could have made it easier and more accessible.
[1] https://github.com/T76-org/drpd or https://www.crowdsupply.com/t76-org/dr-pd
[2] https://hackaday.io/page/399885-a-mac-and-an-ipad-walk-into-...
- imtringued
Guides like this explain why there are so many broken USB-C devices. The guide mentions that you do not need a PD chip for 5Vs, but then tells you that USB C is a cold connector meaning 0V is on VBUS when nothing is connected and jumps straight into the complexities of the PD protocol running over the CC pins instead of explaining how to get the 5V without the PD chip first.
Then in the section where it tells you how to do that, it fails to properly explain how to connect a load switch (10 cent component at 100 units) to get around the 10uF limit. The vast majority of applications will require less than 15 W and a good chunk of them can't get away with 10uF between VBUS and GND so a schematic how to do it in the lowest cost way would have helped here.
Edit: After reading until the very end I got the impression that this is just an ad for Texas Instruments PD controllers.
- kubb
My new iPhone with USB C charging is such an improvement!
Thank goodness for the European Union. If it weren't for them, we'd all be stuck with these flimsy Apple charging cables forever.
- rjh29
Pretty good summary. It can be confusing since type C is "just a connector" but it's pretty heavily coupled with the protocol now.
- xg15
Always found it a bit strange that USB-C is referred to as a "new connector" when it clearly seems to be an entirely new protocol. (Unlike the previous new connectors mini and micro which were just differently-shaped plugs for the same wires)
So is the protocol technically USB 4.0 and USB-C "just" a new connector role defined by that protocol, or did they ditch the versioning and "USB-C" is its own thing?
The guide mentions that USB 4.0 is the first version to require a USB-C connector, but then later refers to the "USB-C protocol". Is that the same as USB 4.0?