SLUSB20C November   2012  – November 2021

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  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: Supply Current
    6. 7.6  Digital Input and Output DC Characteristics
    7. 7.7  Power-on Reset
    8. 7.8  2.5-V LDO Regulator
    9. 7.9  Internal Clock Oscillators
    10. 7.10 ADC (Temperature and Cell Measurement) Characteristics
    11. 7.11 Integrating ADC (Coulomb Counter) Characteristics
    12. 7.12 Data Flash Memory Characteristics
    13. 7.13 I2C-Compatible Interface Communication Timing Requirements
    14. 7.14 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power Modes
        1. 8.4.1.1 BAT INSERT CHECK Mode
        2. 8.4.1.2 NORMAL Mode
        3. 8.4.1.3 SLEEP Mode
      2. 8.4.2 SLEEP+ Mode
      3. 8.4.3 HIBERNATE Mode
    5. 8.5 Programming
      1. 8.5.1 Standard Data Commands
      2. 8.5.2 Extended Data Commands
      3. 8.5.3 Communications
        1. 8.5.3.1 I2C Interface
        2. 8.5.3.2 I2C Time Out
        3. 8.5.3.3 I2C Command Waiting Time
        4. 8.5.3.4 I2C Clock Stretching
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 BAT Voltage Sense Input
        2. 9.2.2.2 SRP and SRN Current Sense Inputs
        3. 9.2.2.3 Sense Resistor Selection
        4. 9.2.2.4 TS Temperature Sense Input
        5. 9.2.2.5 Thermistor Selection
        6. 9.2.2.6 REGIN Power Supply Input Filtering
        7. 9.2.2.7 VCC LDO Output Filtering
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Power Supply Decoupling
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Sense Resistor Connections
      2. 11.1.2 Thermistor Connections
      3. 11.1.3 High-Current and Low-Current Path Separation
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.1 Design Requirements

Several key parameters must be updated to align with a given application's battery characteristics. For highest accuracy gauging, it is important to follow-up this initial configuration with a learning cycle to optimize resistance and maximum chemical capacity (Qmax) values prior to sealing and shipping systems to the field. Successful and accurate configuration of the fuel gauge for a target application can be used as the basis for creating a "golden" gas gauge (.fs) file that can be written to all gauges, assuming identical pack design and Li-ion cell origin (chemistry, lot, and so on). Calibration data is included as part of this golden GG file to cut down on system production time. If going this route, it is recommended to average the voltage and current measurement calibration data from a large sample size and use these in the golden file. Table 9-1, Key Data Flash Parameters for Configuration, shows the items that should be configured to achieve reliable protection and accurate gauging with minimal initial configuration.

Table 9-1 Key Data Flash Parameters for Configuration
NAMEDEFAULTUNITRECOMMENDED SETTING
Design Capacity1000mAhSet based on the nominal pack capacity as interpreted from cell manufacturer's datasheet. If multiple parallel cells are used, should be set to N × Cell Capacity.
Design Energy Scale1—Set to 10 to convert all power values to cWh or to 1 for mWh. Design Energy is divided by this value.
Reserve Capacity-mAh0mAhSet to desired runtime remaining (in seconds / 3600) × typical applied load between reporting 0% SOC and reaching Terminate Voltage, if needed.
Chem ID0100hexShould be configured using TI-supplied Battery Management Studio software. Default open-circuit voltage and resistance tables are also updated in conjunction with this step. Do not attempt to manually update reported Device Chemistry as this does not change all chemistry information! Always update chemistry using the appropriate software tool (that is, BQSTUDIO).
Load Mode1—Set to applicable load model, 0 for constant current or 1 for constant power.
Load Select1—Set to load profile which most closely matches typical system load.
Qmax Cell 01000mAhSet to initial configured value for Design Capacity. The gauge will update this parameter automatically after the optimization cycle and for every regular Qmax update thereafter.
Cell0 V at Chg Term4200mVSet to nominal cell voltage for a fully charged cell. The gauge will update this parameter automatically each time full charge termination is detected.
Terminate Voltage3200mVSet to empty point reference of battery based on system needs. Typical is between 3000 and 3200 mV.
Ra Max Delta44mΩSet to 15% of Cell0 R_a 4 resistance after an optimization cycle is completed.
Charging Voltage4200mVSet based on nominal charge voltage for the battery in normal conditions (25°C, etc). Used as the reference point for offsetting by Taper Voltage for full charge termination detection.
Taper Current100mASet to the nominal taper current of the charger + taper current tolerance to ensure that the gauge will reliably detect charge termination.
Taper Voltage100mVSets the voltage window for qualifying full charge termination. Can be set tighter to avoid or wider to ensure possibility of reporting 100% SOC in outer JEITA temperature ranges that use derated charging voltage.
Dsg Current Threshold60mASets threshold for gauge detecting battery discharge. Should be set lower than minimal system load expected in the application and higher than Quit Current.
Chg Current Threshold75mASets the threshold for detecting battery charge. Can be set higher or lower depending on typical trickle charge current used. Also should be set higher than Quit Current.
Quit Current40mASets threshold for gauge detecting battery relaxation. Can be set higher or lower depending on typical standby current and exhibited in the end system.
Avg I Last Run–299mACurrent profile used in capacity simulations at onset of discharge or at all times if Load Select = 0. Should be set to nominal system load. Is automatically updated by the gauge every cycle.
Avg P Last Run–1131mWPower profile used in capacity simulations at onset of discharge or at all times if Load Select = 0. Should be set to nominal system power. Is automatically updated by the gauge every cycle.
Sleep Current15mASets the threshold at which the fuel gauge enters SLEEP mode. Take care in setting above typical standby currents else entry to SLEEP may be unintentionally blocked.
CC Gain10mΩCalibrate this parameter using TI-supplied BQSTUDIO software and calibration procedure in the TRM. Determines conversion of coulomb counter measured sense resistor voltage to current.
CC Delta10mΩCalibrate this parameter using TI-supplied BQSTUDIO software and calibration procedure in the TRM. Determines conversion of coulomb counter measured sense resistor voltage to passed charge.
CC Offset–1418CountsCalibrate this parameter using TI-supplied BQSTUDIO software and calibration procedure in the TRM. Determines native offset of coulomb counter hardware that should be removed from conversions.
Board Offset0CountsCalibrate this parameter using TI-supplied BQSTUDIO software and calibration procedure in the TRM. Determines native offset of the printed circuit board parasitics that should be removed from conversions.
Pack V Offset0mVCalibrate this parameter using TI-supplied BQSTUDIO software and calibration procedure in the TRM. Determines voltage offset between cell tab and ADC input node to incorporate back into or remove from measurement, depending on polarity.