For most Impedance Track TI battery gauges, a smoothing engine is used to help minimize jumps in the State of Charge (SoC) reported by the gauge. During normal operation of the gauge Full Charge Capacity (FCC) and Remining Capacity (RC) are calculated at multiple points during the charge and discharge of the battery. RC is calculated constantly, at 1 second intervals, and FCC is calculated at less frequent intervals. When FCC is recalculated it can cause a jump of SoC. The smoothing engine will prevent the jump from occurring immediately and it will apply the FCC jump over the full discharge of the battery, this increases the user experience to a stable SoC reported by the gauge.
When the smoothing engine is enabled, the gauge will use the filtered FCC and RC to calculate SoC in the following equation:
SoC = filtered_RC/filtered_FCC
When the smoothing is disabled the gauge will use the unfiltered, or “true” FCC and RC:
SoC = unfiltered_RC/unfiltered_FCC
Absolute State of Charge is based on the Design capacity and unfiltered RC.