SLUUAQ3A April 2016 – October 2022 BQ4050
The BQ4050 monitors the battery for three low-voltage thresholds, EDV0, EDV1, and EDV2. The EDV thresholds can be programmed for determination based on the overall pack voltage or an individual cell level. The EDVV bit in Pack Configuration configures the BQ4050 for overall voltage or single-cell EDV thresholds. If programmed for single cell EDV determination, the BQ4050 determines EDV on the basis of the lowest single-cell voltage.
Fixed EDV thresholds may be programmed in EMF/EDV0, EDV C0 Factor/EDV1, and EDV R0 Factor/EDV2 in mV. If the CEDV bit in Gauge Configuration is set, automatic EDV compensation is enabled and the BQ4050 computes the EDV0, EDV1, and EDV2 thresholds based on the values and the battery’s current discharge rate and temperature.
The BQ4050 disables EDV detection if Current() exceeds the Overload Current threshold programmed in (<DF value>). The BQ4050 resumes EDV threshold detection after Current() drops below the Overload Current threshold. Any EDV threshold detected is reset after charge is applied and VDQ is cleared after 10 mAh of charge.
THRESHOLD | RELATIVE STATE OF CHARGE |
---|---|
EDV0 | 0% |
EDV1 | 3% |
EDV2 | Battery Low % |
The BQ4050 uses the EDV thresholds to apply voltage-based corrections to the RM register according to Table 7-1. The performs EDV-based RM adjustments with Current() ≥ C/32. No EDVs are set if Current() ≥ C/32. The BQ4050 adjusts RM as it detects each threshold. If the voltage threshold is reached before the corresponding capacity on discharge, the BQ4050 reduces RM to the appropriate amount as shown in Table 7-1.
This reduction occurs only if Current() ≥ C/32 when the EDV threshold is detected. If RM reaches the capacity level before the voltage threshold is reached on discharge, the BQ4050 prevents RM from decreasing further until the battery voltage reaches the corresponding threshold only on a full learning cycle discharge. RM is not held at the associated EDV percentage on a non-learning discharge cycle (VDQ = 0) or if current < C/32. If Battery Low % is set to zero, EDV1 and EDV0 corrections are disabled.