The Powecell can act alone as a single cell Lipo battery charger, it can act as a boost
(5V) or buck (3.3V) regulator for your project, or it can perform both of these
functions. No soldering required, if you are only using the board to charge your
battery over USB.
Battery Charger:
The charger on the Powercell uses the MCP73831 from Microchip and can supply up
to 500mA to a single cell LiPo battery. If you charge over the micro-B USB connector,
the charge current will be 100mA. You can also externally charge your battery using
the pins labeled 'charge' using your own 5V power source, at 500mA.
The red stat LED indicates charge status and is ON when charging and OFF when
fully charged.
There is also an under voltage lock out (UVLO) set at 2.6V with a couple of resistors,
along with a jumper on the back of the board to disable the UVLO. The UVLO
prevents your battery voltage from dropping too low and damaging the battery. Only
advanced users should disable the UVLO.
Regulator:
The Powercell uses a TPS61200 switching regulator, from Texas Instruments, with a
3.3V or 5V output. The specifications for how much current you can use from this
board are as follows:
• 5V @ 600mA max
• 3.3V @ 200mA max
The enable (EN) and power save (PS) pins are broken out and pulled high (enabled),
so that you can shut off the regulator to save battery power. If you are permanently
connecting your Powercell into your system, you will need to control the EN pin, so
that when you are not using the system (all power OFF), the regulator can be shut
down as well. You can shut down the regulator by pulling the EN pin low (GND). More
information on pin functions in the TPS61200 datasheet (Resources section below).
How to Use it
There are two basic circuits on this board, and each can be used independently or
together. I will go over both options.
Battery Charger
If all you want to do is charge a battery, simply connect your single cell LiPo battery to
the JST connector and a micro-USB cable from the Powercell to your computer, no
soldering required. You should get about 500mA charge current and the red charge
LED labeled 'stat' will light when charging and go off when finished.
You can also use your own 5V supply and charge over the charge pins labeled '5V'
and 'GND.
