SLUSFC9 December   2023 BQ76972

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information BQ76952
    5. 6.5  Supply Current
    6. 6.6  Digital I/O
    7. 6.7  LD Pin
    8. 6.8  Precharge (PCHG) and Predischarge (PDSG) FET Drive
    9. 6.9  FUSE Pin Functionality
    10. 6.10 REG18 LDO
    11. 6.11 REG0 Pre-regulator
    12. 6.12 REG1 LDO
    13. 6.13 REG2 LDO
    14. 6.14 Voltage References
    15. 6.15 Coulomb Counter
    16. 6.16 Coulomb Counter Digital Filter (CC1)
    17. 6.17 Current Measurement Digital Filter (CC2)
    18. 6.18 Current Wake Detector
    19. 6.19 Analog-to-Digital Converter
    20. 6.20 Cell Voltage Measurement Accuracy
    21. 6.21 Cell Balancing
    22. 6.22 Cell Open Wire Detector
    23. 6.23 Internal Temperature Sensor
    24. 6.24 Thermistor Measurement
    25. 6.25 Internal Oscillators
    26. 6.26 High-side NFET Drivers
    27. 6.27 Comparator-Based Protection Subsystem
    28. 6.28 Timing Requirements - I2C Interface, 100kHz Mode
    29. 6.29 Timing Requirements - I2C Interface, 400kHz Mode
    30. 6.30 Timing Requirements - HDQ Interface
    31. 6.31 Timing Requirements - SPI Interface
    32. 6.32 Interface Timing Diagrams
    33. 6.33 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1  Overview
    2. 7.2  Functional Block Diagram
    3. 7.3  BQ76972 Device Versions
    4. 7.4  Diagnostics
    5. 7.5  Device Configuration
      1. 7.5.1 Commands and Subcommands
      2. 7.5.2 Configuration Using OTP or Registers
      3. 7.5.3 Device Security
      4. 7.5.4 Scratchpad Memory
    6. 7.6  Measurement Subsystem
      1. 7.6.1  Voltage Measurement
        1. 7.6.1.1 Voltage Measurement Schedule
        2. 7.6.1.2 Usage of VC Pins for Cells Versus Interconnect
        3. 7.6.1.3 Cell 1 Voltage Validation During SLEEP Mode
      2. 7.6.2  General Purpose ADCIN Functionality
      3. 7.6.3  Coulomb Counter and Digital Filters
      4. 7.6.4  Synchronized Voltage and Current Measurement
      5. 7.6.5  Internal Temperature Measurement
      6. 7.6.6  Thermistor Temperature Measurement
      7. 7.6.7  Factory Trim of Voltage ADC
      8. 7.6.8  Cell Voltage Measurement Accuracy
        1. 7.6.8.1 Fixed Offset Adjustment
        2. 7.6.8.2 Cell Offset Calibration
      9. 7.6.9  Voltage Calibration (ADC Measurements)
      10. 7.6.10 Voltage Calibration (COV and CUV Protections)
      11. 7.6.11 Current Calibration
      12. 7.6.12 Temperature Calibration
    7. 7.7  Primary and Secondary Protection Subsystems
      1. 7.7.1 Protections Overview
      2. 7.7.2 Primary Protections
      3. 7.7.3 Secondary Protections
      4. 7.7.4 High-Side NFET Drivers
      5. 7.7.5 Protection FETs Configuration and Control
        1. 7.7.5.1 FET Configuration
        2. 7.7.5.2 PRECHARGE and PREDISCHARGE Modes
      6. 7.7.6 Load Detect Functionality
    8. 7.8  Device Hardware Features
      1. 7.8.1  Voltage References
      2. 7.8.2  ADC Multiplexer
      3. 7.8.3  LDOs
        1. 7.8.3.1 Preregulator Control
        2. 7.8.3.2 REG1 and REG2 LDO Controls
      4. 7.8.4  Standalone Versus Host Interface
      5. 7.8.5  Multifunction Pin Controls
      6. 7.8.6  RST_SHUT Pin Operation
      7. 7.8.7  CFETOFF, DFETOFF, and BOTHOFF Pin Functionality
      8. 7.8.8  ALERT Pin Operation
      9. 7.8.9  DDSG and DCHG Pin Operation
      10. 7.8.10 Fuse Drive
      11. 7.8.11 Cell Open Wire
      12. 7.8.12 Low Frequency Oscillator
      13. 7.8.13 High Frequency Oscillator
    9. 7.9  Device Functional Modes
      1. 7.9.1 Overview
      2. 7.9.2 NORMAL Mode
      3. 7.9.3 SLEEP Mode
      4. 7.9.4 DEEPSLEEP Mode
      5. 7.9.5 SHUTDOWN Mode
      6. 7.9.6 CONFIG_UPDATE Mode
    10. 7.10 Serial Communications Interface
      1. 7.10.1 Serial Communications Overview
      2. 7.10.2 I2C Communications
      3. 7.10.3 SPI Communications
        1. 7.10.3.1 SPI Protocol
      4. 7.10.4 HDQ Communications
    11. 7.11 Cell Balancing
      1. 7.11.1 Cell Balancing Overview
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements (Example)
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Performance Plot
      4. 8.2.4 Calibration Process
    3. 8.3 Random Cell Connection Support
    4. 8.4 Startup Timing
    5. 8.5 FET Driver Turn-Off
    6. 8.6 Unused Pins
    7. 8.7 Power Supply Requirements
    8. 8.8 Layout
      1. 8.8.1 Layout Guidelines
      2. 8.8.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.9.4 DEEPSLEEP Mode

The BQ76972 device integrates a DEEPSLEEP mode, which is a low power mode that allows the REG1 and REG2 LDOs to remain powered, but disables other subsystems. In this mode, the protection FETs are all disabled, so no voltage is provided at the battery pack terminals. All protections are disabled, and all voltage, current, and temperature measurements are disabled.

DEEPSLEEP mode can be entered by sending a subcommand over the serial communications interface. The device will exit DEEPSLEEP mode and return to NORMAL mode if directed by a subcommand, or if the RST_SHUT pin is asserted for < 1 second, or if a charger is attached (which is detected by the voltage on the LD pin rising from below VWAKEONLD to exceed it). In addition, if the BAT pin voltage falls below VPORA– VPORA_HYS, the device transitions to SHUTDOWN mode.

When the device exits DEEPSLEEP mode, it first completes a full measurement loop and evaluates conditions relative to enabled protections, to ensure that conditions are acceptable to proceed to NORMAL mode. This may take ≈250 ms plus the time for the measurement loop to complete.

The REG1 and REG2 LDOs will maintain their power state when entering DEEPSLEEP mode based on the configuration setting. The device also provides the ability to keep the LFO running while in DEEPSLEEP mode, which allows for a faster responsiveness to communications and transition back to NORMAL mode, but will consume additional power.

Other than sending a subcommand to exit DEEPSLEEP mode, communications with the device over the serial interface will not cause it to exit DEEPSLEEP mode. However, since no measurements are taken while in DEEPSLEEP mode, there is no new information available for readout.