SLUUCJ0 November   2023 BQ76907

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Battery Notational Conventions
    3.     Trademarks
    4.     Glossary
  3. 1 Introduction
  4. 2 Device Description
    1. 2.1 Overview
    2. 2.2 Functional Block Diagram
  5. 3 Device Configuration
    1. 3.1 Direct Commands and Subcommands
    2. 3.2 Configuration Using OTP or Registers
    3. 3.3 Data Formats
      1. 3.3.1 Unsigned Integer
      2. 3.3.2 Integer
      3. 3.3.3 Hex
  6. 4 Device Security
  7. 5 Measurement Subsystem
    1. 5.1 Voltage Measurement
      1. 5.1.1 Voltage Measurement Schedule
      2. 5.1.2 Unused VC Cell Input Pins
      3. 5.1.3 General Purpose ADCIN Functionality
    2. 5.2 Coulomb Counter and Digital Filters
    3. 5.3 Internal Temperature Measurement
    4. 5.4 Thermistor Temperature Measurement
    5. 5.5 Measurement Calibration
  8. 6 Protection Subsystem
    1. 6.1  Protections Overview
    2. 6.2  Protection FET Drivers
    3. 6.3  Cell Overvoltage Protection
    4. 6.4  Cell Undervoltage Protection
    5. 6.5  Short Circuit in Discharge Protection
    6. 6.6  Overcurrent in Charge Protection
    7. 6.7  Overcurrent in Discharge 1 and 2 Protections
    8. 6.8  Current Protection Latch
    9. 6.9  CHG Detector
    10. 6.10 Overtemperature in Charge Protection
    11. 6.11 Overtemperature in Discharge Protection
    12. 6.12 Internal Overtemperature Protection
    13. 6.13 Undertemperature in Charge Protection
    14. 6.14 Undertemperature in Discharge Protection
    15. 6.15 Host Watchdog Protection
    16. 6.16 Cell Open Wire Detection
    17. 6.17 Voltage Reference Measurement Diagnostic Protection
    18. 6.18 VSS Measurement Diagnostic Protection
    19. 6.19 REGOUT Diagnostic Protection
    20. 6.20 LFO Oscillator Integrity Diagnostic Protection
    21. 6.21 Internal Factory Trim Diagnostic Protection
  9. 7 Device Status and Controls
    1. 7.1 0x00 Control Status() and 0x12 Battery Status() Commands
    2. 7.2 LDOs
    3. 7.3 ALERT Pin Operation
    4. 7.4 TS Pin Operation
    5. 7.5 Programmable Timer
    6. 7.6 Device Event Timing
  10. 8 Operational Modes
    1. 8.1 Overview of Operational Modes
    2. 8.2 NORMAL Mode
    3. 8.3 SLEEP Mode
    4. 8.4 DEEPSLEEP Mode
    5. 8.5 SHUTDOWN Mode
    6. 8.6 CONFIG_UPDATE Mode
  11. 9 I2C Serial Communications
    1. 9.1 I2C Serial Communications Interface
  12. 10Cell Balancing
    1. 10.1 Cell Balancing
  13. 11Commands and Subcommands
    1. 11.1 Direct Commands
    2. 11.2 Bit field Definitions for Direct Commands
      1. 11.2.1  Safety Alert A Register
      2. 11.2.2  Safety Status A Register
      3. 11.2.3  Safety Alert B Register
      4. 11.2.4  Safety Status B Register
      5. 11.2.5  Battery Status Register
      6. 11.2.6  Alarm Status Register
      7. 11.2.7  Alarm Raw Status Register
      8. 11.2.8  Alarm Enable Register
      9. 11.2.9  FET CONTROL Register
      10. 11.2.10 REGOUT CONTROL Register
      11. 11.2.11 DSG FET Driver PWM Control Register
      12. 11.2.12 CHG FET Driver PWM Control Register
    3. 11.3 Command-only Subcommands
    4. 11.4 Subcommands with Data
    5. 11.5 Bit field Definitions for Subcommands
      1. 11.5.1 DEVICE NUMBER Register
      2. 11.5.2 FW VERSION Register
      3. 11.5.3 HW VERSION Register
      4. 11.5.4 SECURITY KEYS Register
      5. 11.5.5 CB ACTIVE CELLS Register
      6. 11.5.6 PROG TIMER Register
      7. 11.5.7 PROT RECOVERY Register
  14. 12Data Memory
    1. 12.1 Calibration
      1. 12.1.1 Calibration:Voltage
        1. 12.1.1.1 Calibration:Voltage:Cell 1 Gain
        2. 12.1.1.2 Calibration:Voltage:Cell 2 Gain Delta
        3. 12.1.1.3 Calibration:Voltage:Cell 3 Gain Delta
        4. 12.1.1.4 Calibration:Voltage:Cell 4 and 5 Gain Delta
        5. 12.1.1.5 Calibration:Voltage:Cell 6 and 7 Gain Delta
        6. 12.1.1.6 Calibration:Voltage:Stack Gain
      2. 12.1.2 Calibration:Current
        1. 12.1.2.1 Calibration:Current:Curr Gain
        2. 12.1.2.2 Calibration:Current:Curr Offset
        3. 12.1.2.3 Calibration:Current:CC1 Gain
        4. 12.1.2.4 Calibration:Current:CC1 Offset
      3. 12.1.3 Calibration:Temperature
        1. 12.1.3.1 Calibration:Temperature:TS Offset
        2. 12.1.3.2 Calibration:Temperature:Int Temp Gain
        3. 12.1.3.3 Calibration:Temperature:Int Temp Offset
    2. 12.2 Settings
      1. 12.2.1 Settings:Configuration
        1. 12.2.1.1 Settings:Configuration:Power Config
        2. 12.2.1.2 Settings:Configuration:REGOUT Config
        3. 12.2.1.3 Settings:Configuration:I2C Address
        4. 12.2.1.4 Settings:Configuration:I2C Config
        5. 12.2.1.5 Settings:Configuration:DA Config
        6. 12.2.1.6 Settings:Configuration:Vcell Mode
        7. 12.2.1.7 Settings:Configuration:Default Alarm Mask
        8. 12.2.1.8 Settings:Configuration:FET Options
        9. 12.2.1.9 Settings:Configuration:Charge Detector Time
      2. 12.2.2 Settings:Cell Balancing
        1. 12.2.2.1 Settings:Cell Balancing:Balancing Configuration
        2. 12.2.2.2 Settings:Cell Balancing:Min Temp Threshold
        3. 12.2.2.3 Settings:Cell Balancing:Max Temp Threshold
        4. 12.2.2.4 Settings:Cell Balancing:Max Internal Temp
      3. 12.2.3 Settings:Protection
        1. 12.2.3.1 Settings:Protection:Enabled Protections A
        2. 12.2.3.2 Settings:Protection:Enabled Protections B
        3. 12.2.3.3 Settings:Protection:DSG FET Protections A
        4. 12.2.3.4 Settings:Protection:CHG FET Protections A
        5. 12.2.3.5 Settings:Protection:Both FET Protections B
        6. 12.2.3.6 Settings:Protection:Body Diode Threshold
        7. 12.2.3.7 Settings:Protection:Cell Open Wire NORMAL Check Time
        8. 12.2.3.8 Settings:Protection:Cell Open Wire SLEEP Check Time
        9. 12.2.3.9 Settings:Protection:Host Watchdog Timeout
    3. 12.3 Protections
      1. 12.3.1 Protections:Cell Voltage
        1. 12.3.1.1 Protections:Cell Voltage:Cell Undervoltage Protection Threshold
        2. 12.3.1.2 Protections:Cell Voltage:Cell Undervoltage Protection Delay
        3. 12.3.1.3 Protections:Cell Voltage:Cell Undervoltage Protection Recovery Hysteresis
        4. 12.3.1.4 Protections:Cell Voltage:Cell Overvoltage Protection Threshold
        5. 12.3.1.5 Protections:Cell Voltage:Cell Overvoltage Protection Delay
        6. 12.3.1.6 Protections:Cell Voltage:Cell Overvoltage Protection Recovery Hysteresis
      2. 12.3.2 Protections:Current
        1. 12.3.2.1  Protections:Current:Overcurrent in Charge Protection Threshold
        2. 12.3.2.2  Protections:Current:Overcurrent in Charge Protection Delay
        3. 12.3.2.3  Protections:Current:Overcurrent in Discharge 1 Protection Threshold
        4. 12.3.2.4  Protections:Current:Overcurrent in Discharge 1 Protection Delay
        5. 12.3.2.5  Protections:Current:Overcurrent in Discharge 2 Protection Threshold
        6. 12.3.2.6  Protections:Current:Overcurrent in Discharge 2 Protection Delay
        7. 12.3.2.7  Protections:Current:Short Circuit in Discharge Protection Threshold
        8. 12.3.2.8  Protections:Current:Short Circuit in Discharge Protection Delay
        9. 12.3.2.9  Protections:Current:Latch Limit
        10. 12.3.2.10 Protections:Current:Recovery Time
      3. 12.3.3 Protections:Temperature
        1. 12.3.3.1  Protections:Temperature:Overtemperature in Charge Protection Threshold
        2. 12.3.3.2  Protections:Temperature:Overtemperature in Charge Protection Delay
        3. 12.3.3.3  Protections:Temperature:Overtemperature in Charge Protection Recovery
        4. 12.3.3.4  Protections:Temperature:Undertemperature in Charge Protection Threshold
        5. 12.3.3.5  Protections:Temperature:Undertemperature in Charge Protection Delay
        6. 12.3.3.6  Protections:Temperature:Undertemperature in Charge Protection Recovery
        7. 12.3.3.7  Protections:Temperature:Overtemperature in Discharge Protection Threshold
        8. 12.3.3.8  Protections:Temperature:Overtemperature in Discharge Protection Delay
        9. 12.3.3.9  Protections:Temperature:Overtemperature in Discharge Protection Recovery
        10. 12.3.3.10 Protections:Temperature:Undertemperature in Discharge Protection Threshold
        11. 12.3.3.11 Protections:Temperature:Undertemperature in Discharge Protection Delay
        12. 12.3.3.12 Protections:Temperature:Undertemperature in Discharge Protection Recovery
        13. 12.3.3.13 Protections:Temperature:Internal Overtemperature Protection Threshold
        14. 12.3.3.14 Protections:Temperature:Internal Overtemperature Protection Delay
        15. 12.3.3.15 Protections:Temperature:Internal Overtemperature Protection Recovery
    4. 12.4 Power
      1. 12.4.1 Power:Sleep
        1. 12.4.1.1 Power:Sleep:Sleep Current
        2. 12.4.1.2 Power:Sleep:Voltage Time
        3. 12.4.1.3 Power:Sleep:Wake Comparator Current
      2. 12.4.2 Power:Shutdown
        1. 12.4.2.1 Power:Shutdown:Shutdown Cell Voltage
        2. 12.4.2.2 Power:Shutdown:Shutdown Stack Voltage
        3. 12.4.2.3 Power:Shutdown:Shutdown Temperature
        4. 12.4.2.4 Power:Shutdown:Auto Shutdown Time
    5. 12.5 Security
      1. 12.5.1 Security:Settings
        1. 12.5.1.1 Security:Settings:Security Settings
        2. 12.5.1.2 Security:Settings:Full Access Key Step 1
        3. 12.5.1.3 Security:Settings:Full Access Key Step 2
    6. 12.6 Data Memory Summary
  15. 13Revision History

4 Device Security

The BQ76907 device includes two security modes: SEALED and FULLACCESS, which can be used to limit the ability to view or change settings.

In SEALED mode, most data and status can be read using commands and subcommands, but only selected settings can be changed. Data memory settings cannot be read or changed directly.

FULLACCESS mode includes SEALED mode functionality, adds the ability to execute additional subcommands, and provides capability to read and modify all device settings.

Selected settings in the device can be modified while the device is in operation through supported commands and subcommands, but in order to modify all settings, the device must enter CONFIG_UPDATE mode, which stops device operation while settings are being updated. After the update is completed, device operation is restarted using the new settings. CONFIG_UPDATE mode is only available in FULLACCESS mode.

The BQ76907 device implements a key-access scheme to move from SEALED to FULLACCESS mode. A unique set of keys must be sent to the device through the subcommand address (0x3E and 0x3F). The keys must be sent consecutively to 0x3E and 0x3F, with no other data written between the keys. Do not set the two keys to identical values, and it is recommended to not use keys which are identical to subcommand addresses. When in SEALED mode, the 0x12 Battery Status()[SEC1, SEC0] bits are set to [1, 1]. When the FULLACCESS keys are correctly received by the device, the bits are set to [0, 1]. The state [0, 0] is not valid and only indicates that the state has not yet been loaded. The state [1, 0] is also not valid.

The FULLACCESS keys are stored in data memory in Security:Full Access Key Step 1 and Security:Keys:Full Access Key Step 2. The access keys are changed during operation using the 0x0035 SECURITY_KEYS() subcommand. This subcommand enables a R/W of the 2 key words (4 bytes). Each word is sent in little endian order using this subcommand.

When using the codes by writing them to 0x3E and 0x3F, they must be sent in little endian order; therefore, if 0x1234 and 0x5678 are written as the FULLACCESS codes to 0x0035 SECURITY_KEYS(), then to unseal requires writing 0x34 and 0x12 to 0x3E and 0x3F, followed by writing 0x78 and 0x56 to 0x3E and 0x3F. The two codes must be written within 5 s of each other to succeed.

To read the keys (only available in FULLACCESS mode, assume for example the keys are 0x1234 0x5678):

  1. Write 0x35 and 0x00 to 0x3E and 0x3F
  2. Read back 4 bytes from the transfer buffer at 0x40–0x43 (for example, 0x34 0x12 0x78 0x56).

To write the keys (only available in FULLACCESS mode):

  1. Write 0x35 and 0x00 to 0x3E and 0x3F.
  2. Write the data in little endian format to the transfer buffer at 0x40–0x43 (for example, 0x34 0x12 0x78 0x56).
  3. Write the checksum to 0x60. The checksum is calculated by inverting the modulo-256 sum of the data and command bytes (for example, 0xB6).
  4. Write the length of 0x08 to 0x61. The length includes the command, data, checksum, and length bytes.

To set the device into SEALED mode when initially powering up, the Security:Security Settings[SEAL] configuration bit must be programmed into OTP. During operation, a device in FULLACCESS mode can be put into SEALED mode by sending the 0x0030 SEAL() subcommand.

The BQ76907 device includes additional means to limit further modification of device settings. If the Security:Security Settings[LOCK_CFG] configuration bit is set, the data memory settings can no longer be modified when the device exits CONFIG_UPDATE mode. If the Security:Security Settings[PERM_SEAL] bit is set, the device cannot be unsealed after it has been sealed. If these bits are not set in OTP, the settings are lost on a full reset and the device is again able to unseal and modify data memory.