SLUSDW2A November   2021  – February 2022 BQ27Z746

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configurations and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
      1. 6.5.1 Supply Current
      2. 6.5.2 Common Analog (LDO, LFO, HFO, REF1, REF2, I-WAKE)
      3. 6.5.3 Battery Protection (CHG, DSG)
      4. 6.5.4 Cell Sensing Output (BAT_SP, BAT_SN)
      5. 6.5.5 Gauge Measurements (ADC, CC, Temperature)
      6. 6.5.6 Flash Memory
    6. 6.6 Digital I/O: DC Characteristics
    7. 6.7 Digital I/O: Timing Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  BQ27Z746 Processor
      2. 7.3.2  Battery Parameter Measurements
        1. 7.3.2.1 Coulomb Counter (CC) and Digital Filter
        2. 7.3.2.2 ADC Multiplexer
        3. 7.3.2.3 Analog-to-Digital Converter (ADC)
        4. 7.3.2.4 Internal Temperature Sensor
        5. 7.3.2.5 External Temperature Sensor Support
      3. 7.3.3  Power Supply Control
      4. 7.3.4  Bus Communication Interface
      5. 7.3.5  Low Frequency Oscillator
      6. 7.3.6  High Frequency Oscillator
      7. 7.3.7  1.8-V Low Dropout Regulator
      8. 7.3.8  Internal Voltage References
      9. 7.3.9  Overcurrent in Discharge Protection
      10. 7.3.10 Overcurrent in Charge Protection
      11. 7.3.11 Short-Circuit Current in Discharge Protection
      12. 7.3.12 Primary Protection Features
      13. 7.3.13 Battery Sensing
      14. 7.3.14 Gas Gauging
      15. 7.3.15 Zero Volt Charging (ZVCHG)
      16. 7.3.16 Charge Control Features
      17. 7.3.17 Authentication
    4. 7.4 Device Functional Modes
      1. 7.4.1 Lifetime Logging Features
      2. 7.4.2 Configuration
        1. 7.4.2.1 Coulomb Counting
        2. 7.4.2.2 Cell Voltage Measurements
        3. 7.4.2.3 Auto Calibration
        4. 7.4.2.4 Temperature Measurements
  8. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements (Default)
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Changing Design Parameters
      3. 8.2.3 Calibration Process
      4. 8.2.4 Gauging Data Updates
        1. 8.2.4.1 Application Curve
  9. 9 Power Supply Requirements
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Orderable, and Packaging Information

Package Options

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

7.4 Device Functional Modes

This device supports five modes, but the current consumption varies, based on firmware control of certain functions and modes of operation:

  • NORMAL mode: In this mode, the device performs measurements, calculations, protections, and data updates every 250-ms intervals. Between these intervals, the device operates in a reduced power state to minimize total average current consumption. Battery protections are continuously monitored and both protection NFETs are typically on.
  • SLEEP mode: In this mode, the device performs measurements, calculations, and data updates in adjustable time intervals. Between these intervals, the device operates in a reduced power stage to minimize total average current consumption. Battery protections are continuously monitored and both protection NFETs are typically on.
  • SHIP mode: In this mode, the device measures voltage and temperature very infrequently and at shorter ADC conversion times, and current is not measured or coulomb counted. Current is assumed to be, and reported as, 0 mA. Therefore, the device tracks the battery's state-of-charge from OCVs. The measurements performed each interval are cell voltage, temperature, and PACK voltage (every fourth interval). Processing is minimized by reducing the number of calculations. Some calculations are performed less frequently: only after voltage and temperature are measured. These less frequent calculations include updating firmware-based protections, lifetime data, and the voltage and temperature ranges of the advanced charge algorithm. Other calculations, such as updating RemainingCapacity() and FullChargeCapacity(), are not performed at all with the assumption the system is off and will not communicate with the gauge. Battery protections are continuously monitored and both protection NFETs remain on, typically.
  • SHELF mode: In this mode, power consumption is reduced even further from SHIP mode by turning off the CHG and DSG NFETs and all hardware-based protections. Due to this, no external power is available to the system in SHELF mode. The device measures voltage and temperature very infrequently and at shorter ADC conversion times, and current is not measured or coulomb counted. Current is assumed to be, and reported as, 0 mA. Therefore, the device tracks the battery's state-of-charge from voltage measurements. The measurements performed each interval are cell voltage, temperature and PACK voltage (every fourth interval). Processing is minimized by reducing the number of calculations. Some calculations are performed less frequently: only after voltage and temperature are measured. These less frequent calculations include updating firmware-based protections, lifetime data, and the voltage and temperature ranges of the advanced charge algorithm. Other calculations, such as updating RemainingCapacity() and FullChargeCapacity(), are not performed at all with the assumption the system is off and will not communicate with the gauge.
  • SHUTDOWN mode: In this mode, the device is completely disabled to minimize power consumption and to avoid depleting the battery.