I have searched around on this forum but haven't found what I was looking for regarding charging from USB.

Has anyone successfully designed a charging circuit using the current from the USB port?

If I am drawing current from the USB port the amount of current drawn is how much my circuit needs? Or does it stop at 500 mA or something like that? I'd like to pull as much current as I can to rapid charge a battery.

And would there be an issues about charging while you are sending data via USB?

Thanks for the info!

-Henk Visser

I have not done this myself, but:

You can steal 100mA without asking for it. That is how some of those funny USB powered devices like lights and vibrating neck massagers etc work.

To use <500mA should only be done once you have negotiated this with the host.

If your sevices uses, say 100mA then there is np reason why you should not negotiate for 500mA and use the rest for charging.

Thanks for the info!