I have a data-logger project that needs to run from a 3-cell Lithium Polymer battery. It has 5v and 3.3v regulators to provide regulated power to the system.
I want to build the battery into the device so that it is all self contained. When the user plugs in the USB cable to download the data, I also want the battery to charge from the USB.
So I'm looking for a chip / circuit that can take the 5v USB as an input and boost it to the voltage (12.6?) necessary to charge the 3S lipo, and manage the charge. The system still needs to operate while charging. When USB is unplugged the system should run from the battery.
Best Answer
As options for three-cell Li-ion/LiPo charging, you may choose from
Alternatively, you may use LTC4007 (datasheet), however, this requires an input voltage of at least 6V, so you'll have to supply an in-between boost mechanism from the USB voltage of 5V.