SLVSDU0B September   2017  – September 2019 BQ25910

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Device Power-On-Reset (POR)
      2. 7.3.2  Device Power Up from Battery without Input Source
      3. 7.3.3  Device Power Up from Input Source
      4. 7.3.4  Power Up REGN LDO
      5. 7.3.5  Poor Source Qualification
      6. 7.3.6  Converter Power-Up
      7. 7.3.7  Three-Level Buck Converter Theory of Operation
      8. 7.3.8  Host Mode and Default Mode
        1. 7.3.8.1 Host Mode and Default Mode in BQ25910
      9. 7.3.9  Battery Charging Management
        1. 7.3.9.1 Autonomous Charging Cycle
      10. 7.3.10 Master Charger and Parallel Charger Interactions
      11. 7.3.11 Battery Charging Profile
        1. 7.3.11.1 Charging Termination
        2. 7.3.11.2 Differential Battery Voltage Remote Sensing
        3. 7.3.11.3 Charging Safety Timer
    4. 7.4 Device Functional Modes
      1. 7.4.1 Lossless Current Sensing
      2. 7.4.2 Dynamic Power Management
      3. 7.4.3 Interrupt to Host (INT)
      4. 7.4.4 Protections
        1. 7.4.4.1 Voltage and Current Monitoring
          1. 7.4.4.1.1 Input Over-Voltage (VVBUS_OV)
          2. 7.4.4.1.2 Input Under-Voltage (VPOORSRC)
          3. 7.4.4.1.3 Flying Capacitor Over- or Under-Voltage Protection (VCFLY_OVP and VCFLY_UVP)
          4. 7.4.4.1.4 Over Current Protection
        2. 7.4.4.2 Thermal Regulation and Thermal Shutdown
        3. 7.4.4.3 Battery Protection
          1. 7.4.4.3.1 Battery Over-Voltage Protection (BATOVP)
    5. 7.5 Programming
      1. 7.5.1 Serial Interface
      2. 7.5.2 Data Validity
      3. 7.5.3 START and STOP Conditions
      4. 7.5.4 Byte Format
      5. 7.5.5 Acknowledge (ACK) and Not Acknowledge (NACK)
      6. 7.5.6 Slave Address and Data Direction Bit
      7. 7.5.7 Single Read and Write
      8. 7.5.8 Multi-Read and Multi-Write
    6. 7.6 Register Maps
      1. 7.6.1 I2C Registers
        1. 7.6.1.1  Battery Voltage Regulation Limit Register (Address = 0h) [reset = AAh]
          1. Table 5. REG00 Register Field Descriptions
        2. 7.6.1.2  Charger Current Limit Register (Address = 1h) [reset = 46h]
          1. Table 6. REG01 Register Field Descriptions
        3. 7.6.1.3  Input Voltage Limit Register (Address = 2h) [reset = 04h]
          1. Table 7. REG02 Register Field Descriptions
        4. 7.6.1.4  Input Current Limit Register (Address = 3h) [reset = 13h]
          1. Table 8. REG03 Register Field Descriptions
        5. 7.6.1.5  Reserved Register (Address = 4h) [reset = 03h]
          1. Table 9. REG04 Register Field Descriptions
        6. 7.6.1.6  Charger Control 1 Register (Address = 5h) [reset = 9Dh]
          1. Table 10. REG05 Register Field Descriptions
        7. 7.6.1.7  Charger Control 2 Register (Address = 6h) [reset = 33h]
          1. Table 11. REG06 Register Field Descriptions
        8. 7.6.1.8  INT Status Register (Address = 7h) [reset = X]
          1. Table 12. REG07 Register Field Descriptions
        9. 7.6.1.9  FAULT Status Register (Address = 8h) [reset = X]
          1. Table 13. REG08 Register Field Descriptions
        10. 7.6.1.10 INT Flag Status Register (Address = 9h) [reset = 00h]
          1. Table 14. REG09 Register Field Descriptions
        11. 7.6.1.11 FAULT Flag Register (Address = Ah) [reset = 00h]
          1. Table 15. REG0A Register Field Descriptions
        12. 7.6.1.12 INT Mask Register (Address = Bh) [reset = 00h]
          1. Table 16. REG0h Register Field Descriptions
        13. 7.6.1.13 FAULT Mask Register (Address = Ch) [reset = 00h]
          1. Table 17. REG0C Register Field Descriptions
        14. 7.6.1.14 Part Information Register (Address = Dh) [reset = 0Ah]
          1. Table 18. REG0D Register Field Descriptions
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 External Passive Recommendation
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Input Capacitor
        4. 8.2.2.4 Flying Capacitor
        5. 8.2.2.5 Output Capacitor
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
        1. 11.1.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.8.1 Host Mode and Default Mode in BQ25910

The BQ25910 is a host controlled charger, and will automatically shut off when the I2C watchdog timer is not reset within the timer period. In default (HIZ) mode, the device automatically disables charging until the host writes the EN_CHG bit high again and resets the watchdog timer via the WD_RST bit. When the charger is in default mode, WD_STAT bit is HIGH. When the charger is in host mode, WD_STAT bit is LOW.

After power-on-reset, the device starts in default mode with watchdog timer expired. All the registers are in the default settings. In default mode, the device remains in HIZ mode and will not charge the battery.

Writing a 1 to the WD_RST bit forces the charger out of default mode and into host mode. All the device parameters can be programmed by the host. To keep the device in host mode, the host has to reset the watchdog timer by writing 1 to WD_RST bit before the watchdog timer expires (WD_STAT bit is set), or disable watchdog timer by setting WATCHDOG bits = 00.

When the watchdog timer is expired (WD_STAT bit = 1), the device returns to default mode and registers are reset to default values except as detailed in the I2C register section. As long as the watchdog timer is expired (WD_STAT bit = 1), the device remains in Default Mode without charging the battery, regardless of the EN_CHG bit state. In order to enable charge after watchdog expired, write WD_RST = 1, and EN_CHG = 1.

BQ25910 watch_lvsdu0.gifFigure 17. Watchdog Timer Flow Chart

The REG_RST bit can be used to reset all of the registers (except STATUS registers) to their default value at any time.