SLUSDA7A April   2018  – January 2021 BQ25121A

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Ship Mode
        1. 9.3.1.1 Ship Mode Entry and Exit
      2. 9.3.2  High Impedance Mode
      3. 9.3.3  Active Battery Only Connected
      4. 9.3.4  Voltage Based Battery Monitor
      5. 9.3.5  Sleep Mode
      6. 9.3.6  Input Voltage Based Dynamic Power Management (VIN(DPM))
      7. 9.3.7  Input Overvoltage Protection and Undervoltage Status Indication
      8. 9.3.8  Battery Charging Process and Charge Profile
      9. 9.3.9  Dynamic Power Path Management Mode
      10. 9.3.10 Battery Supplement Mode
      11. 9.3.11 Default Mode
      12. 9.3.12 Termination and Pre-Charge Current Programming by External Components (IPRETERM)
      13. 9.3.13 Input Current Limit Programming by External Components (ILIM)
      14. 9.3.14 Charge Current Programming by External Components (ISET)
      15. 9.3.15 Safety Timer
      16. 9.3.16 External NTC Monitoring (TS)
      17. 9.3.17 Thermal Protection
      18. 9.3.18 Typical Application Power Dissipation
      19. 9.3.19 Status Indicators ( PG and INT)
      20. 9.3.20 Chip Disable ( CD)
      21. 9.3.21 Buck (PWM) Output
      22. 9.3.22 Load Switch / LDO Output and Control
      23. 9.3.23 Manual Reset Timer and Reset Output ( MR and RESET)
    4. 9.4 Device Functional Modes
    5. 9.5 Programming
      1. 9.5.1 Serial Interface Description
      2. 9.5.2 F/S Mode Protocol
    6. 9.6 Register Maps
      1. 9.6.1  Status and Ship Mode Control Register
      2. 9.6.2  Faults and Faults Mask Register
      3. 9.6.3  TS Control and Faults Masks Register
      4. 9.6.4  Fast Charge Control Register
      5. 9.6.5  Termination/Pre-Charge Register
      6. 9.6.6  Battery Voltage Control Register
      7. 9.6.7  SYS VOUT Control Register
      8. 9.6.8  Load Switch and LDO Control Register
      9. 9.6.9  Push-button Control Register
      10. 9.6.10 ILIM and Battery UVLO Control Register
      11. 9.6.11 Voltage Based Battery Monitor Register
      12. 9.6.12 VIN_DPM and Timers Register
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Default Settings
        2. 10.2.2.2 Choose the Correct Inductance and Capacitance
        3. 10.2.2.3 Calculations
          1. 10.2.2.3.1 Program the Fast Charge Current (ISET)
          2. 10.2.2.3.2 Program the Input Current Limit (ILIM)
          3. 10.2.2.3.3 Program the Pre-charge/termination Threshold (IPRETERM)
          4. 10.2.2.3.4 TS Resistors (TS)
      3. 10.2.3 Application Performance Curves
        1. 10.2.3.1 Charger Curves
        2. 10.2.3.2 SYS Output Curves
        3. 10.2.3.3 Load Switch and LDO Curves
        4. 10.2.3.4 LS/LDO Output Curves
        5. 10.2.3.5 Timing Waveforms Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Trademarks
    4. 13.4 Support Resources
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.3.15 Safety Timer

At the beginning of the charge cycle, the device starts the safety timer. If charging has not terminated before the programmed safety time, tMAXCHG, expires, the device enters idle mode and charging is disabled. The pre-charge safety time, tPRECHG, is 10% of tMAXCHG. When a safety timer fault occurs, a single 128 µs pulse is sent on the INT pin and the STAT and FAULT bits of the status registers are updated over I2C. The CD pin or power must be toggled in order to clear the safety timer fault. The safety timer duration is programmable using the TMR bits. When the safety timer is active, changing the safety timer duration resets the safety timer. The device also contains a 2X_TIMER bit that enables the 2X timer function to prevent premature safety timer expiration when the charge current is reduced by a load on PMID, SYS, LS/LDO or a NTC condition. When t2X_TIMER function is enabled, the timer is allowed to run at half speed when any loop is active other than CC or CV.