Super capacitor charger/balancer with system backup
The board charges super capacitors and balances them when the system voltage is available. If this power rail fails, super capacitors power bank takes over and sends power back to the power rail - it acts as uninterruptible power supply.
Two capacitors are connected in series, pairs in parallel.
System voltage can be from 3.3V up to 5V. Charging current is 600mA. Backup voltage is 3.15V. The main IC is LTC3110 and it handles all functions of the board.
This board is intended to be a test board for super capacitor chargers and can supply backup power for limited amounts of time.
10 boards will shortly be available for sale and design files will be available at OpenHardware.
@ceech what the overall capacity? I'm trying to figure out how much it would last on one of my nodes before a charge is required. Assuming 5uA sleep consumption and updates are sent every 5 mins, for how long overall capacity is good for?
@alexsh1 I've tested the board with electronic load. It provided 200mA for one minute at 3.15V.
@ceech excellent and with what capacity please?
@alexsh1 Oh, yes. They are 1.5F, 2.7V each.
@ceech you have some in series and some parallel, but with this constant discharge current, I estimate you must have around 6F capacitance.
Enough to power Mega 2560 for 1 minute