Isolated USB2 Expansion Card

Creators & Developers Expansion Card
1

I made an expansion card with an isolated USB2 (type A) port.
Both (upstream and downstream) ports are ESD protected.
Vbus is isolated with a 1 watt DC-DC isolator.

Since the components use about 0.1 watt of power even if nothing is connected to the downstream port i added a DIP switch to disable the module.

FW-EC-isolatedusb-inserted
FW-EC-isolatedusb-inserted1920Ă—3413 279 KB

FW-EC-isolatedusb-uninserted
FW-EC-isolatedusb-uninserted1920Ă—3413 268 KB

This is based on an ADuM3160 USB isolator IC I desoldered from a ready made module like this:

isolatedusb-original
isolatedusb-original1229Ă—591 269 KB

The dimensions of the B0505S/D-1W isolated DC-DC (with unusual orientation) does perfectly fit the EC slot (one reason this project came to be lol).

The PCB manufacturer I used is Aisler. They recommend to not use the Molex connector but a Amphenol 12401981E412A. I somehow messed up the positioning of the new connector. It is to long so the module does not fully fit in the slot, this needs fixing in the next revision.

I put the cad and eda files on GitHub:
https://github.com/schnili/FW-EC-isolatedusb

5 Likes
2

I would be interested to hear, what application or use-case are you using this for?

1 Like
3

It protects the laptop and usb device from damage because of ground loops or faulty usb devices.

I always (used) to carry the A-to-A adaptor so i’d made sense to just include it in the port itself :smile:

The use case that benefits the most is using a (non isolated) portable variable power supply (powerd by usb-c PD) to power another project and have the laptop connected to the project while charging from the same 4 port usb-c power brick the variable power supply is connected to.

1 Like
4

That a cool project!

On a side note: I’m curious about what’s the black expansion card. Is that just a rubber feet on the card, or is that a joystick? :eyes:

5

Its a psp joystick :grin: