Good morning,
I've designed a protection and balancing circuit for a 10S battery back and I've used the BQ76930 as main device for such features (together with a microprocessor).
I've got a problem during balance procedure: while activating a single channel, the following channel suffers a completely wrong voltage reading. After several tentatives, I've found it depends on resistors and capacitors used on each single input channel: series resistor on each channel (named Rc in datasheet) affects the charging of capacitor (named Cc) of the following channel. This is my conclusion.
Into datasheet there are no application schemas for an external balancing circuit. So there isn't any criteria for dimensioning external resistors and capacitors. I've looked to EVB schematic and I've used the same values of components (without understanding reasons for such values) and my solution doesn't work: when I activate the balance of a channel, its voltage readings falls down (1V) and the following channel voltage reading rises up (300-400mV), so readings are not reliable and any kind of balancing algorithm cannot work.
Please let me understand how to design the balancing external circuit for avoiding the above problem. The question seems to be limited to only Rc and Cc, but it is necessary to have some more information because the behavior depends also on what happen inside the BQ76930.
Thank you and regards
Matteo