Hi,
We are having trouble with the BQ76930 chip reading and reporting completely wrong cell measurements, ranging from 0.7V to 24V. This error has occurred on 3 different chips on 2 different boards, and is based off the raw ADC value read by a logic analyser on the I2C-path (i2c read/write, including alerts, with host works as expected). All 3 chips report the same values, and does so immediately after first power on, without any balancing, chg on, or dsg on. We are at a loss as to why this is happening, considering an earlier revision of the same board, without any changes to the AFE, works without problems. The only change is an added host µc drawing power from REGOUT pin; could this damage the BQ-chip somehow? Power drawn should not exceed 30-40mA.
The system is 10 cells at 3.8V, with BQ76930 as AFE and nRF52 as host µc.
I have attached the schematics and board layout, as well as a log of reported cell voltages (adc values, decimal). Any help noticing errors would be greatly appreciated! If any other information is needed let me know.
Cell 1 Cell 2 Cell 3 Cell 4 Cell 5 Cell 6 Cell 7 Cell 8 Cell 9 Cell 10 3425 3108 9468 32116 9970 62917 9970 62658 10229 13954 3425 6479 9468 33941 9970 62917 9970 63969 10229 14213 3425 3885 9468 31859 9970 62917 9970 62658 10229 13954 1616 53808 0 4734 9970 49481 9970 60813 10229 12432 1616 53808 0 4734 9970 64232 9970 60813 10229 12432 3425 2614 9468 27651 9970 62917 9970 62658 10229 14213 2676 47663 9468 31590 9970 62658 9970 62658 10229 13954 3174 47137 9468 31859 9970 62917 9970 62658 10229 13954 1616 53561 2104 31590 9970 61060 9970 60554 10229 12237 1616 53561 2104 31590 9970 61060 9970 60554 10229 12237 3425 0 9468 30277 9970 62917 9970 62658 10229 13954 3425 3108 9468 32381 9970 58546 9970 62658 10229 14213 3425 4208 9193 2614 9970 62917 9970 62658 10229 13954 1879 2865 2104 46085 9970 61060 9970 60813 10229 11460 3174 44611 2104 46085 9970 61060 9970 60813 10229 11460 3425 3885 9468 32381 9970 62917 9970 62658 10229 13954 3425 3626 9468 32116 9970 62917 9970 62658 10229 14213 3425 3626 9468 32116 9970 62917 9970 62658 10229 13954 1616 52589 2104 31590 9970 58546 9970 60813 10229 12432 1616 52589 3108 26165 9970 58546 9970 60813 10229 12432 2931 38370 9468 32116 9970 62917 9970 62658 10229 13954 3174 53091 9468 31590 9970 62917 9970 62658 10229 13954 3425 4471 9468 32905 9970 62917 9970 62658 10229 13707 1616 54565 2104 32634 9723 52589 9970 51318 10229 12237 1616 54565 2104 32634 9723 52589 9970 62658 10229 12237 3425 1554 9468 31329 9970 62423 9970 62658 10229 13954 3425 2367 8416 28173 9970 62917 9970 62658 10229 13954 3174 26418 9468 33166 9970 62917 9970 62658 10229 14213 1616 54565 2104 32634 9970 61315 9970 60813 10229 12432 1616 54565 2104 32634 9970 61315 9970 60813 10229 12432 3425 777 9468 32381 9970 62917 9970 62658 10229 14213 3425 4471 9468 32905 9970 62917 9970 62658 10229 14213 3425 3626 9468 33166 9970 44362 9970 62658 10229 13954 1616 55083 2104 46603 9970 59793 9970 60813 10229 12432 1616 55083 2104 46603 9970 59793 9970 60813 10229 12432
