Hello everyone,
Well the idea is to have something to quick-start a USB handled device or convert any project to portable.
Power management and efficiency is one of the tricky bit to it so I could definitely see interest.
The project would be like the power management of a MP3 player: run 3.3V and 5V from either usb or internal battery. Be able to recharge the battery while using the device. Shut down the device at low battery to protect the cell. (Maybe have a logic warning before shutdown or a breakout connection for analog sensing). It’d be interesting to break out all the usb pin so use the port for data also. (maybe even tossing a usb->uart could be an idea)
I realize that everything is already available but the cost of buying them separately is quite high (both space and $) . I’m in the process of trying to build one for a project and I’d say that about 15-20$ would be competitive with trying to build one with breadboard friendly unit qty purchases.
I’d be very great if it could fit in the same size of you (1100mAh) LiPo cell.
I had the idea when reading this :
http://www.maxim-ic.com/app-notes/index.mvp/id/960
But it’s a 2002 design … maybe there’s something better out there.
Thank you very much.