SLUUAQ3A April 2016 – October 2022 BQ4050
RemainingCapacity() (RM)
RM represents the remaining capacity in the battery. The BQ4050 computes RM in units of either mAh or 10 mWh depending on the selected mode. See BatteryMode() for units configuration.
RM counts up during charge to a maximum value of FCC and down during discharge and self-discharge to a minimum of 0. In addition to charge and self-discharge compensation, the BQ4050 calibrates RM at three low-battery-voltage thresholds, EDV2, EDV1, and EDV0 and three programmable midrange thresholds VOC25, VOC50, and VOC75. This provides a voltage-based calibration to the RM counter.
DesignCapacity() (DC)
DC is the user-specified battery full capacity. It is calculated from Design Capacity and is represented in units of mAh or 10 mWh. It also represents the full-battery reference for the absolute display mode.
FullChargeCapacity() (FCC)
FCC is the last measured discharge capacity of the battery. It is represented in units of either mAh or 10 mWh, depending on the selected mode. On initialization, the BQ4050 sets FCC to the value stored in Last Measured Discharge (FCC). During subsequent discharges, the BQ4050 updates FCC with the last measured discharge capacity of the battery. The last measured discharge of the battery is based on the value in the DCR register after a qualified discharge occurs. Once updated, the BQ4050 writes the new FCC value to data flash in mAh to Last Measured Discharge. FCC represents the full battery reference for the relative display mode and relative state of charge calculations.
Discharge Count Register (DCR)
The DCR register counts up during discharge, independent of RM. DCR counts discharge activity, battery load estimation, and self-discharge increment. The BQ4050initializes DCR, at the beginning of a discharge, to FCC – RM when RM is within the programmed value in Near Full. The DCR initial value of FCC – RM is reduced by FCC/128 if SC = 1 (Bit 5 in Gauge Configuration) and is not reduced if SC = 0. DCR stops counting when the battery voltage reaches the EDV2 threshold on discharge.