SLUSCC8C July   2015  – October 2022 BQ25895M

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
    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 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

8.2.3.5 Converter Power-Up

After the input current limit is set, the converter is enabled and the HSFET and LSFET start switching. If battery charging is disabled, BATFET turns off. Otherwise, BATFET stays on to charge the battery.

The device provides soft-start when system rail is ramped up. When the system rail is below 2.2 V, the input current limit is forced to the lower of 200 mA or IINLIM register setting. After the system rises above 2.2 V, the device limits input current to the lower value of ILIM pin and IILIM register (ICO_EN = 0) or IDPM_LIM register (ICO_EN = 1).

As a battery charger, the device deploys a highly efficient 1.5 MHz step-down switching regulator. The fixed frequency oscillator keeps tight control of the switching frequency under all conditions of input voltage, battery voltage, charge current and temperature, simplifying output filter design.

A type III compensation network allows using ceramic capacitors at the output of the converter. An internal saw-tooth ramp is compared to the internal error control signal to vary the duty cycle of the converter. The ramp height is proportional to the PMID voltage to cancel out any loop gain variation due to a change in input voltage.

In order to improve light-load efficiency, the device switches to PFM control at light load when battery is below minimum system voltage setting or charging is disabled. During the PFM operation, the switching duty cycle is set by the ratio of SYS and VBUS.