SLUSDW2A November   2021  ā€“ 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

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • YAH|15
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.4.2.1 Coulomb Counting

The device uses an integrating delta-sigma analog-to-digital converter (ADC) for current measurement. The ADC measures charge/discharge flow of the battery by measuring the voltage across a very small external sense resistor. The integrating ADC measures a bipolar signal from a range of ā€“100 mV to 100 mV, with a positive value when V(SRP) ā€“ V(SRN), indicating charge current and a negative value indicating discharge current.

The current measurement is performed by measuring the voltage drop across the external sense resistor, which can be as low as 1 mĪ©, and the polarity of the differential voltage determines if the cell is in the CHARGE or DISCHARGE mode.