SLUUCY8 December   2023 BQ77307

 

  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 Protection Subsystem
    1. 5.1  Protections Overview
    2. 5.2  Protection Evaluation and Detection
    3. 5.3  Protection FET Drivers
    4. 5.4  Cell Overvoltage Protection
    5. 5.5  Cell Undervoltage Protection
    6. 5.6  Short Circuit in Discharge Protection
    7. 5.7  Overcurrent in Charge Protection
    8. 5.8  Overcurrent in Discharge 1 and 2 Protections
    9. 5.9  Current Protection Latch
    10. 5.10 CHG Detector
    11. 5.11 Overtemperature in Charge Protection
    12. 5.12 Overtemperature in Discharge Protection
    13. 5.13 Internal Overtemperature Protection
    14. 5.14 Undertemperature in Charge Protection
    15. 5.15 Undertemperature in Discharge Protection
    16. 5.16 Cell Open Wire Detection
    17. 5.17 Voltage Reference Diagnostic Protection
    18. 5.18 VSS Diagnostic Protection
    19. 5.19 REGOUT Diagnostic Protection
    20. 5.20 LFO Oscillator Integrity Diagnostic Protection
    21. 5.21 Internal Factory Trim Diagnostic Protection
  8. 6 Device Status and Controls
    1. 6.1 0x00 Control Status() and 0x12 Battery Status() Commands
    2. 6.2 Unused VC Cell Input Pins
    3. 6.3 LDOs
    4. 6.4 ALERT Pin Operation
    5. 6.5 TS Pin Operation
    6. 6.6 Device Event Timing
  9. 7 Operational Modes
    1. 7.1 Overview of Operational Modes
    2. 7.2 NORMAL Mode
    3. 7.3 SHUTDOWN Mode
    4. 7.4 CONFIG_UPDATE Mode
  10. 8 I2C Serial Communications
    1. 8.1 I2C Serial Communications Interface
  11. 9 Commands and Subcommands
    1. 9.1 Direct Commands
    2. 9.2 Bit Field Definitions for Direct Commands
      1. 9.2.1  Safety Alert A Register
      2. 9.2.2  Safety Status A Register
      3. 9.2.3  Safety Alert B Register
      4. 9.2.4  Safety Status B Register
      5. 9.2.5  Battery Status Register
      6. 9.2.6  Alarm Status Register
      7. 9.2.7  Alarm Raw Status Register
      8. 9.2.8  Alarm Enable Register
      9. 9.2.9  FET CONTROL Register
      10. 9.2.10 REGOUT CONTROL Register
    3. 9.3 Command-only Subcommands
    4. 9.4 Subcommands with Data
    5. 9.5 Bitfield Definitions for Subcommands
      1. 9.5.1 DEVICE NUMBER Register
      2. 9.5.2 FW VERSION Register
      3. 9.5.3 HW VERSION Register
      4. 9.5.4 SECURITY KEYS Register
      5. 9.5.5 PROT RECOVERY Register
  12. 10Data Memory
    1. 10.1 Settings
      1. 10.1.1 Settings:Configuration
        1. 10.1.1.1  Settings:Configuration:Reserved
        2. 10.1.1.2  Settings:Configuration:Power Config
        3. 10.1.1.3  Settings:Configuration:REGOUT Config
        4. 10.1.1.4  Settings:Configuration:I2C Address
        5. 10.1.1.5  Settings:Configuration:I2C Config
        6. 10.1.1.6  Settings:Configuration:TS Mode
        7. 10.1.1.7  Settings:Configuration:Vcell Mode
        8. 10.1.1.8  Settings:Configuration:Default Alarm Mask
        9. 10.1.1.9  Settings:Configuration:FET Options
        10. 10.1.1.10 Settings:Configuration:Charge Detector Time
      2. 10.1.2 Settings:Protection
        1. 10.1.2.1 Settings:Protection:Enabled Protections A
        2. 10.1.2.2 Settings:Protection:Enabled Protections B
        3. 10.1.2.3 Settings:Protection:DSG FET Protections A
        4. 10.1.2.4 Settings:Protection:CHG FET Protections A
        5. 10.1.2.5 Settings:Protection:Both FET Protections B
        6. 10.1.2.6 Settings:Protection:Cell Open Wire Check Time
    2. 10.2 Protections
      1. 10.2.1 Protections:Cell Voltage
        1. 10.2.1.1 Protections:Cell Voltage:Cell Undervoltage Protection Threshold
        2. 10.2.1.2 Protections:Cell Voltage:Cell Undervoltage Protection Delay
        3. 10.2.1.3 Protections:Cell Voltage:Cell Undervoltage Protection Recovery Hysteresis
        4. 10.2.1.4 Protections:Cell Voltage:Cell Overvoltage Protection Threshold
        5. 10.2.1.5 Protections:Cell Voltage:Cell Overvoltage Protection Delay
        6. 10.2.1.6 Protections:Cell Voltage:Cell Overvoltage Protection Recovery Hysteresis
      2. 10.2.2 Protections:Current
        1. 10.2.2.1  Protections:Current:Overcurrent in Charge Protection Threshold
        2. 10.2.2.2  Protections:Current:Overcurrent in Charge Protection Delay
        3. 10.2.2.3  Protections:Current:Overcurrent in Discharge 1 Protection Threshold
        4. 10.2.2.4  Protections:Current:Overcurrent in Discharge 1 Protection Delay
        5. 10.2.2.5  Protections:Current:Overcurrent in Discharge 2 Protection Threshold
        6. 10.2.2.6  Protections:Current:Overcurrent in Discharge 2 Protection Delay
        7. 10.2.2.7  Protections:Current:Short Circuit in Discharge Protection Threshold
        8. 10.2.2.8  Protections:Current:Short Circuit in Discharge Protection Delay
        9. 10.2.2.9  Protections:Current:Latch Limit
        10. 10.2.2.10 Protections:Current:Recovery Time
      3. 10.2.3 Protections:Temperature
        1. 10.2.3.1  Protections:Temperature:Overtemperature in Charge Protection Threshold
        2. 10.2.3.2  Protections:Temperature:Overtemperature in Charge Protection Delay
        3. 10.2.3.3  Protections:Temperature:Overtemperature in Charge Protection Recovery
        4. 10.2.3.4  Protections:Temperature:Undertemperature in Charge Protection Threshold
        5. 10.2.3.5  Protections:Temperature:Undertemperature in Charge Protection Delay
        6. 10.2.3.6  Protections:Temperature:Undertemperature in Charge Protection Recovery
        7. 10.2.3.7  Protections:Temperature:Overtemperature in Discharge Protection Threshold
        8. 10.2.3.8  Protections:Temperature:Overtemperature in Discharge Protection Delay
        9. 10.2.3.9  Protections:Temperature:Overtemperature in Discharge Protection Recovery
        10. 10.2.3.10 Protections:Temperature:Undertemperature in Discharge Protection Threshold
        11. 10.2.3.11 Protections:Temperature:Undertemperature in Discharge Protection Delay
        12. 10.2.3.12 Protections:Temperature:Undertemperature in Discharge Protection Recovery
        13. 10.2.3.13 Protections:Temperature:Internal Overtemperature Protection Threshold
        14. 10.2.3.14 Protections:Temperature:Internal Overtemperature Protection Delay
        15. 10.2.3.15 Protections:Temperature:Internal Overtemperature Protection Recovery
    3. 10.3 Power
      1. 10.3.1 Power:Configuration
        1. 10.3.1.1 Power:Configuration:Voltage CHECK Time
        2. 10.3.1.2 Power:Configuration:Body Diode Threshold
      2. 10.3.2 Power:Shutdown
        1. 10.3.2.1 Power:Shutdown:Shutdown Cell Voltage
        2. 10.3.2.2 Power:Shutdown:Shutdown Stack Voltage
        3. 10.3.2.3 Power:Shutdown:Shutdown Temperature
    4. 10.4 Security
      1. 10.4.1 Security:Settings
        1. 10.4.1.1 Security:Settings:Security Settings
        2. 10.4.1.2 Security:Settings:Full Access Key Step 1
        3. 10.4.1.3 Security:Settings:Full Access Key Step 2
      2. 10.4.2 Data Memory Summary
  13. 11Revision History

5.2 Protection Evaluation and Detection

The BQ77307 device includes protections for cell voltage, pack current, and cell temperature, as well as integrated diagnostics. The timing for the evaluation of these protections is different for current versus the other protections. The cell voltages, internal and thermistor temperature, and the VREF and VSS diagnostics are evaluated at periodic intervals set by Power:Configuration:Voltage CHECK Time, which can be set from 250 ms to 255 seconds. The Short Circuit in Discharge (SCD) protection evaluates the differential voltage across the sense resistor (connected to the SRP and SRN pins) continuously, while the sense resistor voltage is evaluated every 305 μs to implement the Overcurrent in Charge (OCC) and Overcurrent in Discharge 1 and 2 (OCD1, OCD2) protections.

The BQ77307 device includes the capability to evaluate the internal die temperature versus selected thresholds using the difference between two internal transistor base-emitter voltages. This voltage difference is periodically compared to various thresholds, such as the Internal Overtemperature (OTINT) Protection based on Protections:Temperature:Internal Overtemperature Protection Threshold, and the internal overtemperature shutdown (based on Power:Shutdown:Shutdown Temperature).

The BQ77307 device also includes an evaluation of the voltage of an external thermistor on the TS pin to implement several temperature protections (OTC, OTD, UTC, UTD) described in later sections. The device uses an internal, factory trimmed 20-kΩ pullup resistor to bias an external thermistor during each evaluation. The TS pin is configured for thermistor evaluation using the Settings:Configuration:Eval Config[TSMODE] data memory setting. If the pin is not selected for thermistor evaluation, the pullup resistor is not enabled.

To provide a high precision result, the device uses the same 1.8-V internal LDO voltage for the detection threshold as is used for biasing the thermistor pullup resistor, thereby implementing a ratiometric evaluation that removes the error contribution from the LDO voltage level. Because the pullup resistor is only enabled during the periodic pin threshold evaluation, it is recommended to limit the capacitance at this node to less than 4 nF to reduce the effect of incomplete settling when the pullup resistor is biased.