LiPoly charger with USB passthrough?

[djszk]

Is there a type of LiPoly charger that can also pass through USB data, allowing me to expose only one USB jack on my device? I'm using a Teensy with mini-USB in.

Thanks!

[adafruit]

you could connect the 5V from the teensy to the DC input pads of our USB lipoly charger

http://www.adafruit.com/products/259

[djszk]

OK, thanks! How do I get the power back into the Teensy?

[adafruit_support_bill]

What is the goal? You want to run the teensy from the LiPoly? To do that, you would need something like a MintyBoost to get the LiPoly output voltage back up to 5v. Similar to this, except without the solar.

Build the MintyBoost, but skip the resistor network on the data lines (R1, R2, R3 and R4). Connect as in the solar project above - except your power source will be USB instead of a solar panel. Finally, connect the ground lines from the charger & the Minty and jumper the data lines from the charger to the Minty. It will be tricky to solder to the data lines on the mini-usb. If you have room, it might be easier to cannibalize a USB extension cable and tap into the data lines there.

[paulstoffregen]

Maybe you could cut the 5V pads apart on the bottom of the Teensy, and then use the charger instead of soldering a MCP1825 regulator?

The 5V pad is still connected to the power from USB, so you'd solder a wire from that pad on Teensy to the power input pad (next to the USB connector) on the charger. You'd also solder a wire from the charger output to Teeny's center pad, so the Teensy is powered by the battery. If the battery stays above 3.4 volts, you can leave the 3V pad on the side unconnected. Of course, solder a ground wire between the charger's ground and Teensy's ground. The center pin of the regulator pads is ground, or you can solder to either of the normal GND locations.

Configure Teensy for 8 MHz, from the Tools > CPU Speed menu in Arduino, or by editing your makefile and prescaler setting code if working in C. Running at 16 MHz below 4.5 volts is technically overclocking, so best to go with 8 MHz, at least while you're testing everything else.

This is based on some guesswork, so I can't guarantee this will work, but it might be worth a try?