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1 Programming the EEPROM Application Report SLUA414–February 2007 Configuring the bq27010/210 for Gas Gauge Applications ......................................................................................................................... Battery Management ABSTRACT Accurate performance of the bq27x10 gas gauge requires that the 10 user-configurable EEPROM coefficients be programmed to values that reflect the appropriate host system and battery characteristics. This application report provides the basis for determining the optimal EEPROM coefficients from the host system operational characteristics and battery characterization data. Appendix A specifically addresses how to determine the EDV1 threshold compensation with load and temperature from battery characterization data. Appendix B shows how to determine the capacity compensation with load, temperature, and age from battery characterization data. Contents 1 Programming the EEPROM....................................................................... 1 1.1 Initial Last Measured Discharge (ILMD)................................................ 2 1.2 Scaled End-of-Discharge Voltage Final (SEDVF)..................................... 2 1.3 Scaled End-of-Discharge Voltage First (SEDV1)...................................... 3 1.4 Initial Standby Load Current and EDV1 Temperature Compensation (ISLC/EDVT) ............................................................................... 3 1.5 Digital Magnitude Filter and Self-Discharge Rate (DMFSD)......................... 4 1.6 Taper Current (TAPER)................................................................... 4 1.7 Pack Configuration (PKCFG) ............................................................ 5 1.8 Gain Age Factor and Delta EDV1 (GAF/DEDV)....................................... 6 1.9 Discharge Rate Compensation (DCOMP).............................................. 6 1.10 Temperature Compensation (TCOMP)................................................. 7 Appendix A EDVI Compensation ...................................................................... 8 Appendix B Capacity Compensation ................................................................ 11 List of Figures A-1 Discharge Capacity Versus Load Current....................................................... 9 A-2 Discharge Capacity Versus Temperature...................................................... 10 B-1 Capacity Versus Load at 20°C.................................................................. 12 B-2 Capacity Versus Temperature at 1C Load..................................................... 13 B-3 Battery Capacity Versus Cycle Life............................................................. 13 A user can program 10 EEPROM locations to optimize the setup for the specific battery and host characteristics. These EEPROM locations are mapped directly to RAM locations 0x76 to 0x7f. These locations cannot be written by the host except during a special test mode. This test mode can be entered by writing 0xdd to address 0x6e. This action will allow write access to these RAM locations and subsequent transfer of the RAM content into EEPROM. The bq27x10 processing is inhibited while 0x6e contains 0xdd. When EEPROM programming is complete, address 0x6e must be written back to 0x00. The actual EEPROM programming is accomplished by reading each address (after previously writing it with the desired data) and then applying a programming pulse of 21-V amplitude for 10-to-100 ms to the SLUA414–February 2007 Configuring the bq27010/210 for Gas Gauge Applications 1 Submit Documentation Feedback