BQ76940 ADC counts.

Each of the 3 cell groups has an ADC, or 5 inputs to an ADC.  The ADC is not perfectly linear, and each input will have some variation into the ADC (see figure 6-2 ), so each input has a different gain and offset. The part provides an average gain and offset stored in the device. The tolerance allows for variation between the inputs.

You may want to use the average gain and offset, apply your own additional offset calibration at a point of interest, use a different calibration scheme perhaps using a 2 point calibration per cell, and possibly use the method in the datasheet figure 7-2 of referencing the battery stack voltage to correct for changes over conditions or time.

Hi,

I am trying to use the method ( Datasheet Figure 7-2) in my design. Could you guide me on:
1. How to enable the Gain2 calibration for Cell Voltage (14-bit) ADC?
2. Where is the Gain2 Stored? what is the register address? Is it a Read/Write Register?
3. Instead of doing real time calibration, can we calibrate only once and store the Gain2 Value permanently in some Register?

Regards,
Hrishikesh