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Topic starter
I think I have an understanding of the behavior of the Zero4U, but I have limited access to parts and wanted to confirm that my understanding is correct before placing my order.
- Self-powered mode provides up to 2A to all USB ports, but does this include the host port?
- PP22/PP23 are directly connected to the "Alt USB In"/USB-mini connector
- Does sequencing matter when receiving both power from the host and externally? For example, if the host is providing power in bus-powered mode and then 5V externally is plugged in, will the hub switch from bus-powered mode to self-powered automatically?
Posted : 07/04/2025 5:31 am
Self-powered mode provides up to 2A to all USB ports, but does this include the host port?
With default configuration, the host port serves as a source of power, instead of a load.
There is a zero-ohm resistor (R8) between host port and the XH2.54 power connector. There is a 2A polyfuse between the XH2.54 connector and the Vusb of 4 downstream ports.
PP22/PP23 are directly connected to the "Alt USB In"/USB-mini connector
That is correct.
If the host is providing power in bus-powered mode and then 5V externally is plugged in
This is not recommended, because it may also back-feed your Raspberry Pi, unless you remove R8.
It is recommended to do some testings under real enviroment, to figure out if it fits your needs.
Posted : 07/04/2025 10:16 am
Topic starter
I'm using an Android tablet as the host, so my application is a bit different but I think it will work. Thanks for input @admin.
Posted : 07/04/2025 9:02 pm