SLUUD50C October   2024  – April 2026 BQ27Z746 , BQ27Z758

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Notational Conventions
    3.     Battery Notational Conventions
    4.     Trademarks
    5.     Glossary
  3. 1 Introduction
  4. 2 IO Options
    1. 2.1 Configuration of the GPO Pin
  5. 3 Basic Measurement System
    1. 3.1 Introduction
    2. 3.2 Current and Coulomb Counting
    3. 3.3 Voltage
      1. 3.3.1 Cell Voltage
      2. 3.3.2 Pack Voltage
    4. 3.4 Temperature
      1. 3.4.1 Internal Temperature
      2. 3.4.2 Cell Temperature
      3. 3.4.3 Optional Second Temperature Sensor
      4. 3.4.4 Temperature Configuration
  6. 4 Protections
    1. 4.1 Introduction
    2. 4.2 Hardware-Based Protection
      1. 4.2.1 Cell Undervoltage Protection
      2. 4.2.2 Cell Overvoltage Protection
      3. 4.2.3 Overcurrent in Discharge Protection
      4. 4.2.4 Overcurrent in Charge Protection
      5. 4.2.5 Short Circuit in Discharge Protection
      6. 4.2.6 Threshold Targets
    3. 4.3 Firmware Based Protections
      1. 4.3.1  Cell Undervoltage Protection
      2. 4.3.2  Cell Overvoltage Protection
      3. 4.3.3  Overcurrent in Charge Protection
      4. 4.3.4  Overcurrent in Discharge Protection
      5. 4.3.5  Temperature Protections
      6. 4.3.6  Overtemperature in Charge Protection
      7. 4.3.7  Overtemperature in Discharge Protection
      8. 4.3.8  Undertemperature in Charge Protection
      9. 4.3.9  Undertemperature in Discharge Protection
      10. 4.3.10 Precharge Timeout Protection
      11. 4.3.11 Fast Charge Timeout Protection
      12. 4.3.12 Protections Configuration
      13. 4.3.13 FET Options
      14. 4.3.14 Protections Data Flash Values
        1. 4.3.14.1  CUV—Cell Undervoltage
        2. 4.3.14.2  HCUV—Hardware Cell Undervoltage
        3. 4.3.14.3  COV—Cell Overvoltage
        4. 4.3.14.4  HCOV—Hardware Cell Overvoltage
        5. 4.3.14.5  OCC—Overcurrent In Charge
        6. 4.3.14.6  HOCC—Hardware Overcurrent in Charge
        7. 4.3.14.7  OCD—Overcurrent in Discharge
        8. 4.3.14.8  HOCD—Hardware Overcurrent in Discharge
        9. 4.3.14.9  HSCD—Hardware Short Circuit in Discharge
        10. 4.3.14.10 OTC—Overtemperature in Charge
        11. 4.3.14.11 OTD—Overtemperature in Discharge
        12. 4.3.14.12 UTC—Undertemperature in Charge
        13. 4.3.14.13 UTD—Undertemperature in Discharge
  7. 5 Permanent Fail
    1. 5.1 Introduction
    2. 5.2 Safety Cell Undervoltage Permanent Fail
    3. 5.3 Safety Cell Overvoltage Permanent Fail
    4. 5.4 Charge FET Permanent Fail
    5. 5.5 Discharge FET Permanent Fail
    6. 5.6 Permanent Fail Configuration
    7. 5.7 Permanent Fail Data Flash Values
      1. 5.7.1 SUV - Safety Undervoltage
      2. 5.7.2 SOV - Safety Overvoltage
      3. 5.7.3 CFETF - Charge FET Failure
      4. 5.7.4 DFETF - Discharge FET Failure
  8. 6 Battery Sensing Output
    1. 6.1 Introduction
    2. 6.2 Automatic Mode
      1. 6.2.1 RLO Mode
      2. 6.2.2 RLO Charge Mode
      3. 6.2.3 BUFFER Mode
    3. 6.3 Hardware-Based Protections
  9. 7 Power Modes
    1. 7.1 Introduction
    2. 7.2 NORMAL Mode
    3. 7.3 SLEEP Mode
      1. 7.3.1 Device Sleep
    4. 7.4 SHIP Mode
    5. 7.5 SHELF Mode
    6. 7.6 SHUTDOWN Mode
      1. 7.6.1 Voltage-Based Shutdown
      2. 7.6.2 AltManufacturerAccess() MAC Shutdown
      3. 7.6.3 Time-Based Shutdown
    7. 7.7 Power Modes Configuration
  10. 8 Gauging
    1. 8.1  Impedance Track (IT) Model
    2. 8.2  Thermal Model
    3. 8.3  Gauging Capacities
    4. 8.4  Learning Cycles
    5. 8.5  Impedance Track Configuration
    6. 8.6  Gas Gauge Modes
    7. 8.7  QMax and Ra
      1. 8.7.1 QMax Initial Values
      2. 8.7.2 QMax Update Conditions
        1. 8.7.2.1 Base Required Conditions
        2. 8.7.2.2 Tracking QMax Updates
        3. 8.7.2.3 Relaxed Cell OCV
        4. 8.7.2.4 OCV Prediction
        5. 8.7.2.5 Cycle Count Based QMax Degradation
        6. 8.7.2.6 105
        7. 8.7.2.7 Fast QMax Update Conditions
        8. 8.7.2.8 QMax and Fast QMax Update Boundary Check
      3. 8.7.3 Ra Table Initial Values
        1. 8.7.3.1 R_a0 Table
        2. 8.7.3.2 R_a0x Table
      4. 8.7.4 Ra Table Update Conditions
      5. 8.7.5 Fast Resistance Scaling
        1. 8.7.5.1 Calculation of Resistance Scale
        2. 8.7.5.2 Negative Resistance Scale
        3. 8.7.5.3 Reset of Resistance Scale
        4. 8.7.5.4 Application of Resistance Scale
        5. 8.7.5.5 Fast Resistance Scaling Configuration
    8. 8.8  FullChargeCapacity (FCC), RemainingCapacity (RemCap), and RelativeStateOfCharge (RSOC)
      1. 8.8.1 Smoothing Engine
        1. 8.8.1.1 Smoothing to 0% in DISCHARGE Mode
        2. 8.8.1.2 Smoothing to 100% in CHARGE Mode
        3. 8.8.1.3 Smoothing in RELAX Mode
    9. 8.9  Impedance Track (IT) Configuration Options
    10. 8.10 State-Of-Health (SOH)
    11. 8.11 Battery Trip Point (BTP)
  11. 9 Lifetime Data Collection
    1. 9.1 Description
    2. 9.2 Reset
  12. 10Host Interrupts
    1. 10.1 Description
    2. 10.2 Voltage and Temperature Interrupts
    3. 10.3 RSOC Interrupts
    4. 10.4 Host Interrupts Configuration
  13. 11Device Security
    1. 11.1 Description
    2. 11.2 SHA-256 Authentication
      1. 11.2.1 Secure Key
      2. 11.2.2 Authentication Flow
    3. 11.3 Security Modes
      1. 11.3.1 SEALING and UNSEALING Data Flash
      2. 11.3.2 SEALED to UNSEALED
      3. 11.3.3 UNSEALED to FULL ACCESS
  14. 12Advanced Charge Algorithm
    1. 12.1  Introduction
    2. 12.2  Charge Temperature Ranges
    3. 12.3  Voltage Range
      1. 12.3.1 RelativeStateofCharge() Range
    4. 12.4  Charging Current
    5. 12.5  Charging Voltage
      1. 12.5.1 Charge Voltage Compensation for System Impedance
    6. 12.6  Charging Degradation Modes
    7. 12.7  Cell Swelling Control (via Charging Voltage Degradation)
    8. 12.8  Valid Charge Termination
    9. 12.9  Charge and Discharge Alarms
    10. 12.10 Terminate Charge and Discharge Alarms
    11. 12.11 Precharge
    12. 12.12 Charge Disable and Discharge Disable
    13. 12.13 Charge Inhibit
    14. 12.14 Charge Suspend
    15. 12.15 Zero Volt Charging (ZVCHG)
  15. 13Communications
    1. 13.1 HDQ Single-Pin Serial Interface
    2. 13.2 I2C Interface
      1. 13.2.1 I2C Clock Frequency
      2. 13.2.2 I2C Time Out
      3. 13.2.3 I2C Command Waiting Time
      4. 13.2.4 I2C Clock Stretching
  16. 14Manufacture Production
    1. 14.1 Manufacture Testing
      1. 14.1.1 Manufacturing Status Configuration
    2. 14.2 I2C Configuration
    3. 14.3 Manufacturer Information Blocks
    4. 14.4 Verification of Data Flash
    5. 14.5 Calibration
  17. 15Calibration
    1. 15.1 Voltage Calibration
      1. 15.1.1 Cell (BAT) Voltage Calibration
      2. 15.1.2 Pack (PACK) Voltage Calibration
      3. 15.1.3 Voltage Calibration Data Flash
    2. 15.2 Current Calibration
      1. 15.2.1 CC Gain/Capacity Gain Calibration
      2. 15.2.2 Deadbands
        1. 15.2.2.1 Current Deadband
        2. 15.2.2.2 Coulomb Counter Deadband
      3. 15.2.3 Current Calibration Data Flash
    3. 15.3 Temperature Calibration
      1. 15.3.1 Internal Temperature Sensor Calibration
      2. 15.3.2 TS Calibration
      3. 15.3.3 Temperature Calibration Data Flash
      4. 15.3.4 Cell Temp Model
      5. 15.3.5 Internal Temp Model
      6. 15.3.6 2nd Temperature Model
  18. 16Data Commands
    1. 16.1 Standard Data Commands
      1. 16.1.1  0x00/01 ManufacturerAccess()/ControlStatus()
      2. 16.1.2  0x02/03 AtRate()
      3. 16.1.3  0x04/05 AtRateTimeToEmpty()
      4. 16.1.4  0x06/07 Temperature()
      5. 16.1.5  0x08/09 Voltage()
      6. 16.1.6  0x0A/0B BatteryStatus()
      7. 16.1.7  0x0C/0D Current()
      8. 16.1.8  0x10/11 RemainingCapacity()
      9. 16.1.9  0x12/13 FullChargeCapacity()
      10. 16.1.10 0x14/15 AverageCurrent()
      11. 16.1.11 0x16/17 AverageTimeToEmpty()
      12. 16.1.12 0x18/19 AverageTimeToFull()
      13. 16.1.13 0x1E/1F MaxLoadCurrent()
      14. 16.1.14 0x20/21 MaxLoadTimeToEmpty()
      15. 16.1.15 0x22/23 AveragePower()
      16. 16.1.16 0x28/29 InternalTemperature()
      17. 16.1.17 0x2A/2B CycleCount()
      18. 16.1.18 0x2C/2D RelativeStateOfCharge()—RSOC
      19. 16.1.19 0x2E/2F StateOfHealth()
      20. 16.1.20 0x30/31 ChargingVoltage()
      21. 16.1.21 0x32/33 ChargingCurrent()
      22. 16.1.22 0x34/35 TerminateVoltage()
      23. 16.1.23 0x36/0x37/0x38/0x39 Timestamp()
      24. 16.1.24 QMax Cycles() 0x3A/3B
      25. 16.1.25 0x3C/3D DesignCapacity()
      26. 16.1.26 0x3E/3F AltManufacturerAccess()
      27. 16.1.27 0x40/0x5F MACData()
      28. 16.1.28 0x60 MACDataChecksum()
      29. 16.1.29 0x61 MACDataLength()
      30. 16.1.30 0x62/63 VoltHiSetThreshold
      31. 16.1.31 0x64/65 VoltHiClearThreshold
      32. 16.1.32 0x66/67 VoltLoSetThreshold
      33. 16.1.33 0x68/69 VoltLoClearThreshold
      34. 16.1.34 0x6A TempHiSetThreshold
      35. 16.1.35 0x6B TempHiClearThreshold
      36. 16.1.36 0X6C TempLoSetThreshold
      37. 16.1.37 0x6D TempLoClearThreshold
      38. 16.1.38 0x6E InterruptStatus()
      39. 16.1.39 0x6F SOCSetDeltaThreshold
    2. 16.2 0x00, 0x01 ManufacturerAccess() and 0x3E, 0x3F AltManufacturerAccess()
      1. 16.2.1  AltManufacturerAccess() 0x0001 Device Type
      2. 16.2.2  AltManufacturerAccess() 0x0002 Firmware Version
      3. 16.2.3  AltManufacturerAccess() 0x0003 Hardware Version
      4. 16.2.4  AltManufacturerAccess() 0x0004 Instruction Flash Signature
      5. 16.2.5  AltManufacturerAccess() 0x0005 Static DF Signature
      6. 16.2.6  AltManufacturerAccess() 0x0006 Chemical ID
      7. 16.2.7  AltManufacturerAccess() 0x0007 Pre_MACWrite
      8. 16.2.8  AltManufacturerAccess() 0x0008 Static Chem DF Signature
      9. 16.2.9  AltManufacturerAccess() 0x0009 All DF Signature
      10. 16.2.10 AltManufacturerAccess() 0x000B SHELF Enable
      11. 16.2.11 AltManufacturerAccess() 0x000C SHELF Disable
      12. 16.2.12 AltManufacturerAccess() 0x0010 SHUTDOWN Mode
      13. 16.2.13 AltManufacturerAccess() 0x0012 Device Reset
      14. 16.2.14 AltManufacturerAccess() 0x0015 SHIP Mode Enable
      15. 16.2.15 AltManufacturerAccess() 0x0016 SHIP Mode Disable
      16. 16.2.16 AltManufacturerAccess() 0x0017 QMax Day
      17. 16.2.17 AltManufacturerAccess() 0x001F CHG FET Toggle
      18. 16.2.18 AltManufacturerAccess() 0x0020 DSG FET Toggle
      19. 16.2.19 AltManufacturerAccess() 0x0021 Gauging
      20. 16.2.20 AltManufacturerAccess() 0x0022 FET Control
      21. 16.2.21 AltManufacturerAccess() 0x0023 Lifetime Data Collection
      22. 16.2.22 AltManufacturerAccess() 0x0024 Permanent Failure
      23. 16.2.23 AltManufacturerAccess() 0x0028 Lifetime Data Reset
      24. 16.2.24 AltManufacturerAccess() 0x0029 Permanent Fail Data Reset
      25. 16.2.25 AltManufacturerAccess() 0x002D CALIBRATION Mode
      26. 16.2.26 AltManufacturerAccess() 0x002E Lifetime Data Flush
      27. 16.2.27 AltManufacturerAccess() 0x002F Lifetime Data SPEED UP Mode
      28. 16.2.28 AltManufacturerAccess() 0x0030 Seal Device
      29. 16.2.29 AltManufacturerAccess() 0x0035 Security Keys
      30. 16.2.30 AltManufacturerAccess() 0x0041 Device Reset
      31. 16.2.31 AltManufacturerAccess() 0x0047 Tambient Sync
      32. 16.2.32 AltManufacturerAccess() 0x004A Device Name
      33. 16.2.33 AltManufacturerAccess() 0x004B Device Chem
      34. 16.2.34 AltManufacturerAccess() 0x004C Manufacturer Name
      35. 16.2.35 AltManufacturerAccess() 0x004D Manufacture Date
      36. 16.2.36 AltManufacturerAccess() 0x004E Serial Number
      37. 16.2.37 ManufacturerAccess() 0x0050 SafetyAlert
      38. 16.2.38 ManufacturerAccess() 0x0051 SafetyStatus
      39. 16.2.39 AltManufacturerAccess() 0x0052 PFAlert
        1. 16.2.39.1 PF Alert A+B
        2. 16.2.39.2 PF Alert C+D
      40. 16.2.40 AltManufacturerAccess() 0x0053 PFStatus
        1. 16.2.40.1 PF Status A+B
        2. 16.2.40.2 PF Status C+D
      41. 16.2.41 AltManufacturerAccess() 0x0054 OperationStatus
        1. 16.2.41.1 Operation Status A
        2. 16.2.41.2 Operation Status B
      42. 16.2.42 AltManufacturerAccess() 0x0055 ChargingStatus
        1. 16.2.42.1 Temp Range
        2. 16.2.42.2 Charging Status
      43. 16.2.43 AltManufacturerAccess() 0x0056 GaugingStatus
      44. 16.2.44 AltManufacturerAccess() 0x0057 ManufacturingStatus
      45. 16.2.45 AltManufacturerAccess() 0x0060 Lifetime Data Block 1
      46. 16.2.46 AltManufacturerAccess() 0x0061 Lifetime Data Block 2
      47. 16.2.47 AltManufacturerAccess() 0x0062 Lifetime Data Block 3
      48. 16.2.48 ManufacturerAccess() 0x0063 Lifetime Data Block 4
      49. 16.2.49 ManufacturerAccess() 0x0064 Lifetime Data Block 5
      50. 16.2.50 AltManufacturerAccess() 0x0065–0x006B Lifetime SOC Range Table Data Blocks
      51. 16.2.51 AltManufacturerAccess() 0x006C Lifetime Data Block 13
      52. 16.2.52 AltManufacturerAccess() 0x0070 ManufacturerInfo
      53. 16.2.53 AltManufacturerAccess() 0x0071 DAStatus1
      54. 16.2.54 AltManufacturerAccess() 0x0072 DAStatus2
      55. 16.2.55 AltManufacturerAccess() 0x0073 ITStatus1
      56. 16.2.56 AltManufacturerAccess() 0x0074 ITStatus2
      57. 16.2.57 AltManufacturerAccess() 0x0075 ITStatus3
      58. 16.2.58 AltManufacturerAccess() 0x0077 FCC_SOH
      59. 16.2.59 AltManufacturerAccess() 0x0078 Filtered Capacity
      60. 16.2.60 AltManufacturerAccess() 0x007A ManufacturerInfoB
      61. 16.2.61 AltManufacturerAccess() 0x007B ManufacturerInfoC
      62. 16.2.62 AltManufacturerAccess() 0x0097 FET Control Override
      63. 16.2.63 AltManufacturerAccess() 0x00A3 System Reset Enable
      64. 16.2.64 AltManufacturerAccess() 0x00A4 System Reset
      65. 16.2.65 AltManufacturerAccess() 0x00B0 ChargingVoltageOverride
      66. 16.2.66 AltManufacturerAccess() 0x00B1 BattSenseOutput
      67. 16.2.67 AltManufacturerAccess() 0x00E0 Ra Table Cell0
      68. 16.2.68 AltManufacturerAccess() 0x0F00 ROM Mode
      69. 16.2.69 Data Flash Access() 0x4000–0x5FFF
      70. 16.2.70 AltManufacturerAccess() 0x7C40 Switch to HDQ
      71. 16.2.71 AltManufacturerAccess() 0xF080 Exit Calibration Output Mode
      72. 16.2.72 AltManufacturerAccess() 0xF081 Output CC and ADC for Calibration
      73. 16.2.73 AltManufacturerAccess() 0xF083 OutputTemperatureCal
      74. 16.2.74 AltManufacturerAccess() 0xF0A0 ProtectorCalibration
      75. 16.2.75 AltManufacturerAccess() 0xF0A1 ProtectorImage1
      76. 16.2.76 AltManufacturerAccess() 0xF0A2 ProtectorImage2
      77. 16.2.77 AltManufacturerAccess() 0xF0A3 ProtectorImageSave
      78. 16.2.78 AltManufacturerAccess() 0xF0A4 ProtectorImageLock
      79. 16.2.79 AltManufacturerAccess() 0xF0A5 ProtectorFactoryConfig
  19. 17Data Flash Access and Format
    1. 17.1 Data Flash Access
      1. 17.1.1 Minimum Voltage
    2. 17.2 Data Formats
      1. 17.2.1 Unsigned Integer
      2. 17.2.2 Integer
      3. 17.2.3 Floating Point
      4. 17.2.4 Hex
      5. 17.2.5 String
  20. 18Data Flash Summary
    1. 18.1 Data Flash Summary
  21. 19Revision History

8.8 FullChargeCapacity (FCC), RemainingCapacity (RemCap), and RelativeStateOfCharge (RSOC)

The Impedance Track algorithm applies QMax, impedance, temperature, voltage, and current data to predict the runtime FullChargeCapacity(), RemainingCapacity(), and RelativeStateOfCharge(). These values are updated if any of the following conditions are met, reflecting the battery capacity in real time:

  • QMax update occurs
  • Ra update occurs
  • At onset of charge and discharge
  • Valid charge termination
  • Every 1 hour in RELAX mode after an OCV has been taken
  • If temperature changes more than 5°C
  • Every second when current is measured and passed charge is accumulated