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

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • YFF|36
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.4 Flying Capacitor

Flying capacitor selection must meet criteria related to current ripple and voltage ripple. Just as the input capacitor, the flying capacitor should also have enough ripple current rating to absorb the RMS current through it:

Equation 4. BQ25910 qu4_lvsdu0.gif

This function becomes maximum when D = 0.5, because at that point the capacitor is in series with the inductor for a complete switching cycle, and their RMS currents are the same. The flying capacitor should be sized to handle the full charge current in the scenario where D = 0.5.

BQ25910 bq25910-flying-capacitor-RMS-current-vs-vbus.gifFigure 47. Flying Capacitor RMS Current vs. VBUS with Fixed VBAT and ICHG

Additionally, the flying capacitor voltage ripple should be kept under 10% of VBUS/2 to ensure loop stability. This quantity is given by the following equation:

Equation 5. BQ25910 qu5_lvsdu0.gif

It is recommended to use at least two 16-V, 10-μF, low ESR ceramic capacitors in parallel to achieve both RMS current rating and maintain voltage ripple <10% in the flying capacitor for up-to 6-A charge current application. The following curve shows what the ripple voltage of CFLY might look like for such a configuration by taking into account voltage derating of the capacitor and plugging the effective capacitance value into equation above at different charge currents and VBUS voltages.

BQ25910 bq25910-flying-capacitor-ripple-vs-vbus.gifFigure 48. Flying Capacitor Ripple Voltage vs. VBUS with Fixed VBAT

Table 22. Recommended CFLY Values

CHARGE CURRENT CFLY CONFIGURATION
ICHG < 3.5 A 1 x 0603 (10 μF, X5R, 16 V)
ICHG > 3.5 A 2 x 0603 (10 μF, X5R, 16 V)