Is there a human readable USB PD 3.0 specs somewhere, or PD 3.0 trigger chip? - Page 1
Forum section: electronics / beginners

author: LinuxHata
author_rank: Frequent Contributor
timestamp: January 14, 2025, 06:15:41 am
content: I found this document:https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/138/USB_5F00_PD_5F00_R3_5F00_0-V1.1-20170112.pdfBut it is very large and contains huge amount of "noise" data.All I want is something like that:To receive, say, 12.5 volts from USB PD 3.0 charger, you need to send the following packet(s) of data via this pin at that level.Any ideas?I want to have my own USB PD 3.0 trigger, with adjustable voltage and I don't need LCD screens and extra bells and whistles of USB power meters.For USB PD 2.0 There's an excellent chip by Injoinic - IP2721. It has one set pin, and whenever you leave it float, pull high or pull down, output voltage changes to 5, 12 or 20 volts. But this is PD 2.0 I'd like to have something like that, with PD 3.0 suppoty.

author: Jwillis
author_rank: Super Contributor
timestamp: January 15, 2025, 01:47:44 am
content: According to the data sheet it has PD3.0 support.https://www.lcsc.com/datasheet/lcsc_datasheet_2006111335_INJOINIC-IP2721_C603176.pdf

author: thm_w
author_rank: Super Contributor
timestamp: January 15, 2025, 01:57:45 am
content: There are plenty of simple USB trigger boards available. You can either get one for each voltage, or one with switches.https://www.aliexpress.com/item/1005006997248362.htmlhttps://www.aliexpress.com/item/1005006179191517.html

author: LinuxHata
author_rank: Frequent Contributor
timestamp: January 15, 2025, 07:01:20 pm
content: IP2721 supports PD 3.0, but it still triggers only fixed available voltages, like 5-12-20 volts, it does not allow for fine voltage setting.Same for aliexpress boards, they also only switch in PD 2.0 range.

author: ksjh
author_rank: Regular Contributor
timestamp: January 15, 2025, 07:29:12 pm
content: Have you already found theCH32X035?I have a few of those at home, but had no time to play with them so far.There are some projects on github (incl. source code) how to use the CH32X035 for PD PPS, e.g.,https://github.com/wagiminator/CH32X035-USB-PD-Adapter

author: LinuxHata
author_rank: Frequent Contributor
timestamp: January 15, 2025, 08:20:46 pm
content: It sounds interesting, but looks overkill, and I don't need that OLED screens, etc.I only need simplified protocol description, so I can implement it on my side.

author: LinuxHata
author_rank: Frequent Contributor
timestamp: January 15, 2025, 08:27:12 pm
content: By the way, I think I've found the required chip- AP33772, but it is NRND...

author: langwadt
author_rank: Super Contributor
timestamp: January 15, 2025, 08:34:22 pm
content: https://www.g3gg0.de/esp32/esp32-pd-usb-pd-using-esp32-zigbee-crib/?

author: ksjh
author_rank: Regular Contributor
timestamp: January 15, 2025, 08:34:47 pm
content: Yes, you are right, the complete CH32X035 USB-PD adapter would be overkill, but I think it would be relatively easy to use the CH32X035 MCU (just the chip, e.g., in TSSOP20) in your own projects and PCB designs, since it already contains the PD PHY and provides a simple way to handle the protocol negotiations for PPS between your sink and the source (power supply). It is also quite cheap. You can look into the source code in the github repo and re-use some code. The toolchain is open and available for various operating systems. You do not need a separate programmer for the MCU, you can upload your firmware via USB. But, as mentioned earlier, I have not tried this myself, yet.

author: ksjh
author_rank: Regular Contributor
timestamp: January 15, 2025, 08:38:35 pm
content: Quote from: langwadt on January 15, 2025, 08:34:22 pmVery nice, but I have seen they use a CH224K for the PD trigger. As far as I have read in the datasheet, this chip does not support PPS, just fixed PD voltages.EDIT:Now I see they created a new version where the ESP32 handled the PD protocol in software, even PPS. This is great. Thanks for the link.

author: ksjh
author_rank: Regular Contributor
timestamp: January 15, 2025, 08:44:18 pm
content: Quote from: LinuxHata on January 15, 2025, 08:27:12 pmBut the AP33772Sstill is.It provides some nice features. On the other hand, it costs twice as much as the CH32X035 when you buy in volume and is no smaller either (and does not provide a RISC-V core).