SLUUB65B May 2015 – December 2022
Prediction accuracy for remaining capacity simulations can be further improved in systems with excessive trace lengths between cell and fuel gauge or fuel gauge and system point of load by setting a nominal value in Trace Resistance or Downstream Resistance, respectively. The fuel gauge adds the Trace Resistance and Downstream Resistance to the cell resistance values used in capacity simulations to obtain a more realistic voltage drop under load in simulated discharges when faced with nontrivial trace parasitics in a given pack design. Likewise, trace resistance is removed from any resistance measurements made during discharge prior to storing in data flash.
Trace Resistance is the nominal resistance between the cell and the coulomb counter measurement point in a given application. Flex cabling and long copper traces on the PCB itself can contribute to this resistance and inject error into the SOC prediction. The fuel gauge will offset cell resistance with this value to improve RemainingCapacity() estimation.
Downstream Resistance is the nominal resistance between the coulomb counter measurement point and the system voltage node in a given application. Long copper traces on the PCB itself can contribute to this resistance and inject error into the SOC prediction. The fuel gauge will offset cell resistance with this value to improve RemainingCapacity() estimation.
Subclass ID | Subclass | Offset | Name | Data Type | Value | Unit | ||
---|---|---|---|---|---|---|---|---|
Min | Max | Default | ||||||
80 | IT Cfg | 92 | Trace Resistance | I2 | 0 | 32767 | 0 | mΩ |
94 | Downstream Resistance | I2 | 0 | 32767 | 0 | mΩ |