SLUSE86A April   2022  – April 2024 BQ76922

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 BQ76922
    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 Voltage References
    14. 6.14 Coulomb Counter
    15. 6.15 Coulomb Counter Digital Filter (CC1)
    16. 6.16 Current Measurement Digital Filter (CC2)
    17. 6.17 Current Wake Detector
    18. 6.18 Analog-to-Digital Converter
    19. 6.19 Cell Balancing
    20. 6.20 Cell Open Wire Detector
    21. 6.21 Internal Temperature Sensor
    22. 6.22 Thermistor Measurement
    23. 6.23 Internal Oscillators
    24. 6.24 High-side NFET Drivers
    25. 6.25 Comparator-Based Protection Subsystem
    26. 6.26 Timing Requirements – I2C Interface, 100kHz Mode
    27. 6.27 Timing Requirements – I2C Interface, 400kHz Mode
    28. 6.28 Timing Requirements – HDQ Interface
    29. 6.29 Interface Timing Diagrams
    30. 6.30 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1  Overview
    2. 7.2  Functional Block Diagram
    3. 7.3  Diagnostics
    4. 7.4  Device Configuration
      1. 7.4.1 Commands and Subcommands
      2. 7.4.2 Configuration Using OTP or Registers
      3. 7.4.3 Device Security
      4. 7.4.4 Scratchpad Memory
    5. 7.5  Measurement Subsystem
      1. 7.5.1  Voltage Measurement
        1. 7.5.1.1 Voltage Measurement Schedule
        2. 7.5.1.2 Using VC Pins for Cells Versus Interconnect
        3. 7.5.1.3 Cell 1 Voltage Validation During SLEEP Mode
      2. 7.5.2  General Purpose ADCIN Functionality
      3. 7.5.3  Coulomb Counter and Digital Filters
      4. 7.5.4  Synchronized Voltage and Current Measurement
      5. 7.5.5  Internal Temperature Measurement
      6. 7.5.6  Thermistor Temperature Measurement
      7. 7.5.7  Factory Trim of Voltage ADC
      8. 7.5.8  Voltage Calibration (ADC Measurements)
      9. 7.5.9  Voltage Calibration (COV and CUV Protections)
      10. 7.5.10 Current Calibration
      11. 7.5.11 Temperature Calibration
    6. 7.6  Primary and Secondary Protection Subsystems
      1. 7.6.1 Protections Overview
      2. 7.6.2 Primary Protections
      3. 7.6.3 Secondary Protections
      4. 7.6.4 High-Side NFET Drivers
      5. 7.6.5 Protection FETs Configuration and Control
        1. 7.6.5.1 FET Configuration
        2. 7.6.5.2 PRECHARGE and PREDISCHARGE Modes
      6. 7.6.6 Load Detect Functionality
    7. 7.7  Device Hardware Features
      1. 7.7.1  Voltage References
      2. 7.7.2  ADC Multiplexer
      3. 7.7.3  LDOs
        1. 7.7.3.1 Preregulator Control
        2. 7.7.3.2 REG1 LDO Control
      4. 7.7.4  Standalone Versus Host Interface
      5. 7.7.5  Multifunction Pin Controls
      6. 7.7.6  RST_SHUT Pin Operation
      7. 7.7.7  CFETOFF, DFETOFF, and BOTHOFF Pin Functionality
      8. 7.7.8  ALERT Pin Operation
      9. 7.7.9  Fuse Drive
      10. 7.7.10 Cell Open Wire
      11. 7.7.11 Low Frequency Oscillator
      12. 7.7.12 High Frequency Oscillator
    8. 7.8  Device Functional Modes
      1. 7.8.1 Overview
      2. 7.8.2 NORMAL Mode
      3. 7.8.3 SLEEP Mode
      4. 7.8.4 DEEPSLEEP Mode
      5. 7.8.5 SHUTDOWN Mode
      6. 7.8.6 CONFIG_UPDATE Mode
    9. 7.9  Serial Communications Interface
      1. 7.9.1 Serial Communications Overview
      2. 7.9.2 I2C Communications
      3. 7.9.3 HDQ Communications
    10. 7.10 Cell Balancing
      1. 7.10.1 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
  10. 9 Power Supply Requirements
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RSN|32
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.6.1 Protections Overview

An extensive protection subsystem is integrated within BQ76922, which can monitor a variety of parameters, initiate protective actions, and autonomously recover based on conditions. The device also includes a wide range of flexibility, such that the device can be configured to monitor and initiate protective action, but with recovery controlled by the host processor, or such that the device only monitors and alerts the host processor whenever conditions warrant protective action, but with action and recovery fully controlled by the host processor.

The primary protection subsystem includes a suite of individual protections which can be individually enabled and configured, including cell undervoltage and overvoltage, overcurrent in charge, three separate overcurrent in discharge protections, short circuit current in discharge, cell overtemperature and undertemperature in charge and discharge, FET overtemperature, a host processor communication watchdog timeout, and PRECHARGE mode timeout. The cell undervoltage and overvoltage, overcurrent in charge, overcurrent in discharge 1 and 2, and short circuit in discharge protections are based on comparator thresholds, while the remaining protections (such as those involving temperature, host watchdog, and precharging) are based on firmware on the internal controller.

The device integrates NFET drivers for high-side CHG and DSG protection FETs, which can be configured in a series or parallel configuration. An integrated charge pump generates a voltage which is driven onto the NFET gates based on host command or the on-chip protection subsystem settings. Support is also included for high-side PFETs used to implement a precharge and predischarge functionality.

The secondary protection suite within the BQ76922 device can react to more serious faults and take action to permanently disable the pack, by initiating a Permanent Fail (PF). The secondary safety provides protection against safety cell undervoltage and overvoltage, safety overcurrent in charge and discharge, safety overtemperature for cells and FETs, excessive cell voltage imbalance, internal memory faults, and internal diagnostic failures.

When a Permanent Fail has occurred, the BQ76922 device can be configured to either simply provide a flag, or to indefinitely disable the protection FETs, or to assert the FUSE pin to permanently disable the pack. The FUSE pin can be used to blow an in-line fuse and also can monitor if a separate secondary protector IC has attempted to blow the fuse.