SLUAAT6B July   2024  – June 2026 BQ41Z50

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Manufacture Testing
  5. 2Calibration
    1. 2.1 Cell Voltage Calibration
    2. 2.2 Per-Cell Auto-Calibration
      1. 2.2.1 Command Overview
      2. 2.2.2 Message Structure
        1. 2.2.2.1 Data Payload Format
        2. 2.2.2.2 Per-Cell Voltage Format
      3. 2.2.3 SMBus Block Protocol
        1. 2.2.3.1 Command Format
      4. 2.2.4 Procedure
    3. 2.3 BAT Voltage Calibration
    4. 2.4 PACK Voltage Calibration
    5. 2.5 Current Calibration
      1. 2.5.1 CC Offset Calibration
      2. 2.5.2 Board Offset Calibration
      3. 2.5.3 CC Gain Calibration
    6. 2.6 Temperature Calibration
      1. 2.6.1 Internal Temperature Sensor Calibration
      2. 2.6.2 TS1–TS2–TS3–TS4 Calibration
  6. 3Summary
  7. 4References
  8. 5Revision History

2.5.2 Board Offset Calibration

Note:

Due to hardware improvements in this device, Board Offset calibration is not necessary. Only run the Board Offset Calibration procedure if board offset current is observed.

  1. Verify that Offset Calibration was performed first.
  2. Apply a known current of 0mA, and verify no current is flowing through the sense resistor connected between the SRP and SRN pins.
  3. If ManufacturerStatus()[CAL] = 0, send 0x002D to ManufacturerAccess() to enable the [CAL] flag.
  4. Send 0xF081 to ManufacturerAccess() to enable raw current output on ManufacturerData().
  5. Poll ManufacturerData() until ZZ increments by 2 before reading data.
  6. Obtain the ADC conversion readings of current from ManufacturerData():
    • ADCCC = AAaa of ManufacturerData()

      Is ADCCC < 0x8000? If yes, use ADCCC; otherwise, ADCCC = –(0xFFFF – AAaa + 0x0001).

  7. Average several readings for higher accuracy. Poll ManufacturerData() until ZZ increments to indicate that updated values are available:
    • ADCCC = [ADCCC(reading n) + … + ADCCC(reading 1)]/n
  8. Read Coulomb Counter Offset Samples from data flash.
  9. Calculate offset value:
    • Board offset = (ADCCC – CC Offset) × Coulomb Counter Offset Samples
  10. Write the new Board Offset value to data flash.
  11. Re-check the current reading. If the reading is not accurate, repeat steps 1 – 10.
  12. Send 0x002D to ManufacturerAccess() to clear the [CAL] flag if all calibration is complete.