SLUA450A January   2008  – November 2022 BQ27421-G1 , BQ27425-G2A , BQ27425-G2B , BQ27441-G1 , BQ27505-J2 , BQ27505-J3 , BQ27505-J4 , BQ27505-J5 , BQ27520-G4 , BQ27530-G1 , BQ27531-G1 , BQ27545-G1 , BQ27546-G1 , BQ27741-G1 , BQ40Z50 , BQ40Z50-R1 , BQ40Z50-R2

 

  1.   Theory and Implementation of Impedance Track™ Battery Fuel-Gauging Algorithm in bq2750x Family
  2.   Trademarks
  3. 1Summary of the Algorithm Operation
  4. 2Parameters Updated by the Gas Gauge in More Detail
    1. 2.1 Modes of Algorithm Operation
    2. 2.2 Update of Chemical Depth of Discharge (DOD)
    3. 2.3 Update of Qmax
    4. 2.4 Update of Resistance
    5. 2.5 Update of Temperature Model
    6. 2.6 Update of DataRAM.Remaining Capacity (RM) and DataRAM.Full Charge Capacity (FCC)
    7. 2.7 Update of DataRAM.Remaining Capacity( ) and DataRAM.State Of Charge( ) Values
  5. 3Real Application Example
    1. 3.1 GSM Smart Phone Application
  6. 4Revision History

2.1 Modes of Algorithm Operation

The algorithm differentiates between charge, discharge, and relaxation modes of operation. During charge mode, the DataRAM.Flags( ) [DSG] bit is cleared, and during discharge and relaxation mode, it is set. Entry and exit of each mode is controlled by Data Flash (DF) parameters in the subclass Gas Gauging: Current Thresholds section as illustrated in Figure 2-1. Charge mode is exited, and relaxation mode is entered when DataRAM.Average Current( ) goes below DF.Quit Current after DF.Chg Relax Time period. Discharge mode is entered when DataRAM.Average Current( ) goes below DF.Dsg Current Threshold and after DF. Quit Relax Time period. Discharge mode is exited, and relaxation mode is entered when DataRAM.Average Current( ) goes above negative DF.Quit Current threshold and after DF.Dsg Relax Time period. Charge mode is entered when DataRAM.Average Current( ) goes above DF.Chg Current Threshold and after DF.Quit Relax Time period.