SLUSBK2I October   2013  – March 2022 BQ76920 , BQ76930 , BQ76940

PRODMIX  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1. 6.1 Versions
    2. 6.2 BQ76920 Pin Diagram
    3. 6.3 BQ76930 Pin Diagram
    4. 6.4 BQ76940 Pin Diagram
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Subsystems
        1. 8.3.1.1 Measurement Subsystem Overview
          1. 8.3.1.1.1 Data Transfer to the Host Controller
          2. 8.3.1.1.2 14-Bit ADC
            1. 8.3.1.1.2.1 Optional Real-Time Calibration Using the Host Microcontroller
          3. 8.3.1.1.3 16-Bit CC
          4. 8.3.1.1.4 External Thermistor
          5. 8.3.1.1.5 Die Temperature Monitor
          6. 8.3.1.1.6 16-Bit Pack Voltage
          7. 8.3.1.1.7 System Scheduler
        2. 8.3.1.2 Protection Subsystem
          1. 8.3.1.2.1 Integrated Hardware Protections
          2. 8.3.1.2.2 Reduced Test Time
        3. 8.3.1.3 Control Subsystem
          1. 8.3.1.3.1 FET Driving (CHG AND DSG)
            1. 8.3.1.3.1.1 High-Side FET Driving
          2. 8.3.1.3.2 Load Detection
          3. 8.3.1.3.3 Cell Balancing
          4. 8.3.1.3.4 Alert
          5. 8.3.1.3.5 Output LDO
        4. 8.3.1.4 Communications Subsystem
    4. 8.4 Device Functional Modes
      1. 8.4.1 NORMAL Mode
      2. 8.4.2 SHIP Mode
    5. 8.5 Register Maps
      1. 8.5.1 Register Details
      2. 8.5.2 Read-Only Registers
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Device Timing
      2. 9.1.2 Random Cell Connection
      3. 9.1.3 Power Pin Diodes
      4. 9.1.4 Alert Pin
      5. 9.1.5 Sense Inputs
      6. 9.1.6 TSn Pins
      7. 9.1.7 Unused Pins
      8. 9.1.8 Configuring Alternative Cell Counts
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Step-by-Step Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
    3. 12.3 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Trademarks
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.3.1.1.6 16-Bit Pack Voltage

Once converted to digital form, each cell voltage is added up and the summation result stored in the BAT registers. The sum is divided by 4 so that the result of summing 15 cells fits in the 16-bit value. This 16-bit value has a nominal LSB of 1.532 mV.

The following shows how to convert the 16-bit pack voltage ADC reading into an analog voltage. This value also uses the GAIN and OFFSET stored into EEPROM.

The ADC transfer function is a linear equation defined as follows:

Equation 9. V(BAT) = 4 × GAIN × ADC(cell) + (#Cells x OFFSET)

GAIN is stored in units of µV/LSB, while OFFSET is stored in mV units.