SLUSC88C March   2015  – October 2022 BQ25895

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings (1)
    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 Functional Block Diagram
    2. 8.2 Feature Description
      1. 8.2.1  Device Power-On-Reset (POR)
      2. 8.2.2  Device Power Up from Battery without Input Source
      3. 8.2.3  Device Power Up from Input Source
        1. 8.2.3.1 Power Up REGN Regulation (LDO)
        2. 8.2.3.2 Poor Source Qualification
        3. 8.2.3.3 Input Source Type Detection
          1. 8.2.3.3.1 D+/D– Detection Sets Input Current Limit
          2. 8.2.3.3.2 Force Input Current Limit Detection
        4. 8.2.3.4 Input Voltage Limit Threshold Setting (VINDPM Threshold)
        5. 8.2.3.5 Converter Power-Up
      4. 8.2.4  Input Current Optimizer (ICO)
      5. 8.2.5  Boost Mode Operation from Battery
      6. 8.2.6  Power Path Management
        1. 8.2.6.1 Narrow VDC Architecture
        2. 8.2.6.2 Dynamic Power Management
        3. 8.2.6.3 Supplement Mode
      7. 8.2.7  Battery Charging Management
        1. 8.2.7.1 Autonomous Charging Cycle
        2. 8.2.7.2 Battery Charging Profile
        3. 8.2.7.3 Charging Termination
        4. 8.2.7.4 Resistance Compensation (IRCOMP)
        5. 8.2.7.5 Thermistor Qualification
          1. 8.2.7.5.1 Cold/Hot Temperature Window in Charge Mode
          2. 8.2.7.5.2 Cold/Hot Temperature Window in Boost Mode
        6. 8.2.7.6 Charging Safety Timer
      8. 8.2.8  Battery Monitor
      9. 8.2.9  Status Outputs (STAT, and INT)
        1. 8.2.9.1 Charging Status Indicator (STAT)
        2. 8.2.9.2 Interrupt to Host (INT)
      10. 8.2.10 BATET (Q4) Control
        1. 8.2.10.1 BATFET Disable Mode (Shipping Mode)
        2. 8.2.10.2 BATFET Enable (Exit Shipping Mode)
        3. 8.2.10.3 BATFET Full System Reset
      11. 8.2.11 Current Pulse Control Protocol
      12. 8.2.12 Input Current Limit on ILIM
      13. 8.2.13 Thermal Regulation and Thermal Shutdown
        1. 8.2.13.1 Thermal Protection in Buck Mode
        2. 8.2.13.2 Thermal Protection in Boost Mode
      14. 8.2.14 Voltage and Current Monitoring in Buck and Boost Mode
        1. 8.2.14.1 Voltage and Current Monitoring in Buck Mode
          1. 8.2.14.1.1 Input Overvoltage (ACOV)
          2. 8.2.14.1.2 System Overvoltage Protection (SYSOVP)
        2. 8.2.14.2 Current Monitoring in Boost Mode
          1. 8.2.14.2.1 Boost Mode Overvoltage Protection
      15. 8.2.15 Battery Protection
        1. 8.2.15.1 Battery Overvoltage Protection (BATOVP)
        2. 8.2.15.2 Battery Over-Discharge Protection
        3. 8.2.15.3 System Overcurrent Protection
      16. 8.2.16 Serial Interface
        1. 8.2.16.1 Data Validity
        2. 8.2.16.2 START and STOP Conditions
        3. 8.2.16.3 Byte Format
        4. 8.2.16.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 8.2.16.5 Target Address and Data Direction Bit
        6. 8.2.16.6 Single Read and Write
        7. 8.2.16.7 Multi-Read and Multi-Write
    3. 8.3 Device Functional Modes
      1. 8.3.1 Host Mode and Default Mode
    4. 8.4 Register Maps
      1. 8.4.1  REG00
      2. 8.4.2  REG01
      3. 8.4.3  REG02
      4. 8.4.4  REG03
      5. 8.4.5  REG04
      6. 8.4.6  REG05
      7. 8.4.7  REG06
      8. 8.4.8  REG07
      9. 8.4.9  REG08
      10. 8.4.10 REG09
      11. 8.4.11 REG0A
      12. 8.4.12 REG0B
      13. 8.4.13 REG0C
      14. 8.4.14 REG0D
      15. 8.4.15 REG0E
      16. 8.4.16 REG0F
      17. 8.4.17 REG10
      18. 8.4.18 REG11
      19. 8.4.19 REG12
      20. 8.4.20 REG13
      21. 8.4.21 REG14
  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 Inductor Selection
        2. 9.2.2.2 Buck Input Capacitor
        3. 9.2.2.3 System Output Capacitor
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Glossary
    6. 12.6 Electrostatic Discharge Caution
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.7.1 Autonomous Charging Cycle

With battery charging is enabled (CHG_CONFIG bit = 1 and CE pin is low), the device autonomously completes a charging cycle without host involvement. The device default charging parameters are listed in Table 8-4 always control the charging operations and optimize the charging parameters by writing to the corresponding registers through I2C.

Table 8-4 Charging Parameter Default Setting
DEFAULT MODE BQ25895
Charging Voltage 4.208 V
Charging Current 2.048 A
Pre-charge Current 128 mA
Termination Current 256 mA
Temperature Profile Cold/Hot
Safety Timer 12 hour

A new charge cycle starts when the following conditions are valid:

  • Converter starts
  • Battery charging is enabled by setting CHG_CONFIG bit, /CE pin is low and ICHG register is not 0 mA
  • No thermistor fault on TS pin
  • No safety timer fault
  • BATFET is not forced to turn off (BATFET_DIS bit = 0)

The charger device automatically terminates the charging cycle when the charging current is below termination threshold, charge voltage is above recharge threshold, and device not in DPM mode or thermal regulation. When a full battery voltage is discharged below recharge threshold (threshold selectable via VRECHG bit), the device automatically starts a new charging cycle. After the charge is done, either toggle CE pin or CHG_CONFIG bit can initiate a new charging cycle.

The STAT output indicates the charging status of charging (LOW), charging complete or charge disable (HIGH) or charging fault (Blinking). The STAT output can be disabled by setting STAT_DIS bit. In addition, the status register (CHRG_STAT) indicates the different charging phases: 00-charging disable, 01-precharge, 10-fast charge (constant current) and constant voltage mode, 11-charging done. Once a charging cycle is completed, an INT is asserted to notify the host.