I’m looking to charge and balance a 2S solution, with a wide input voltage range, without the need for an additional buck / boost converter. Bucking down to 5v for the MP2672A, only to have it boost again to the pack voltage (~ 8.4 - 8.7v depending on the chemistry) isn’t ideal and will generate a lot of heat in our consumer product.
Wide input range from 5v - 12v
I2C Control desirable, plus standalone defaults
2S, Balanced
4.2 x 2 or 4.35 x 2 charged voltages (8.4v / 8.7v pack)
No need to buck then boost
How would these two chips even be connected, or is there a better solution I’m not thinking of?
This active balancer you have selected is ideal when high currents are required for rebalancing in applications like large energy storage systems. We have options that have cell balancing and charging but these are for boost only. The part I would look into for this is the MP2672. Maybe you can consider a buck-boost at the input to create a stable input voltage for MP2672 to enable you to only boost.
So the MP2672 might work for us. Can you confirm the minimum fast / bulk charge current?
Our batteries are only 545 mAh each (2x).
In the electrical specifications table, it states the minimum as 0.9 / 1.8A, with Riset at 6kOhms.
There is no other entry in the table for when Riset is at 24kOhms, but on page 21 it states that if Riset is at 24kOhms the programmable range begins at 125 mA.
Also the pre-charge (Ipre) current appears fixed at typically 300mA, yet the termination current is a percentage of Icc.
At 300 mA fixed, it’s actually 545 / 0.55 C of our cells, which is more or less the fast / bulk phase, rather than the pre-charge phase…