SLUSDQ4 April 2019 BQ79606A-Q1
The cell balancing done comparator threshold (VCBDONE) is configurable using the CB_DONE_THRESH register. The voltage selected is set for all cells. The cells that are being balanced are monitored by a single comparator in a "round robin" fashion. The comparator tests the voltage for tCYCLE. Additionally, the comparator signal is deglitched for tdgOVUVCB (set using the COMP_DG[OVUV_DG] bits). The deglitch is a count up/down style deglitch. During the monitoring cycle, the comparator checks the voltage. A counter is incremented when the comparator is tripped, and decremented when the comparator is not tripped. Once the counter reaches the threshold, the cell balancing switch is disabled and the corresponding CB_DONE[CELL*] bit is set. Once the cell balancing for that cell is terminated, the cell balancing does not restart for the remainder of the cell balancing sequence regardless of the cell voltage. Similar to the hardware comparators, the cell balancing comparator may be programmed to perform BIST as it is monitoring the cell voltages. The BIST is identical to the OVUV BIST as described in CB_DONE, OVUV, and OTUT Built-In Self Test (BIST). Once the cell balancing is enabled (CONTROL2[BAL_GO]=1), changes to the CB_DONE_THRESH and CB_DONE registers are ignored until the cycle is completed (CB_DONE is cleared when CONTROL2[BAL_GO] is set). Cell balancing must be disabled and then restarted to be able to change the settings.
The CBDONE function overrides the OVUV function (if enabled). During the cell balancing cycle, with CBDONE enabled, the OVUV function is paused (if enabled).
CB_DONE_THRESH[ENABLE] bit controls the CBDONE comparator function, when the bit is set to 0 it disables the CBDONE comparator.