SLUSBH2G March   2013  – March 2019

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Schematic
      2.      Charger Efficiency vs Input Voltage
  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 Electrical Characteristics
    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 Maximum Power Point Tracking
      2. 7.3.2 Battery Undervoltage Protection
      3. 7.3.3 Battery Overvoltage Protection
      4. 7.3.4 Battery Voltage within Operating Range (VBAT_OK Output)
      5. 7.3.5 Storage Element / Battery Management
      6. 7.3.6 Programming OUT Regulation Voltage
      7. 7.3.7 Step Down (Buck) Converter
      8. 7.3.8 Nano-Power Management and Efficiency
    4. 7.4 Device Functional Modes
      1. 7.4.1 Main Boost Charger Disabled (Ship Mode) - (VSTOR > VSTOR_CHGEN and EN = HIGH)
      2. 7.4.2 Cold-Start Operation (VSTOR < VSTOR_CHGEN, VIN_DC > VIN(CS) and PIN > PIN(CS), EN = don't care)
      3. 7.4.3 Main Boost Charger Enabled (VSTOR > VSTOR_CHGEN and EN = LOW )
        1. 7.4.3.1 Buck Converter Enabled (VSTOR > VBAT_UV, EN = LOW and VOUT_EN = HIGH )
      4. 7.4.4 Thermal Shutdown
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Energy Harvester Selection
      2. 8.1.2 Storage Element Selection
      3. 8.1.3 Inductor Selection
        1. 8.1.3.1 Boost Charger Inductor Selection
        2. 8.1.3.2 Buck Converter Inductor Selection
      4. 8.1.4 Capacitor Selection
        1. 8.1.4.1 VREF_SAMP Capacitance
        2. 8.1.4.2 VIN_DC Capacitance
        3. 8.1.4.3 VSTOR Capacitance
        4. 8.1.4.4 VOUT Capacitance
        5. 8.1.4.5 Additional Capacitance on VSTOR or VBAT
    2. 8.2 Typical Applications
      1. 8.2.1 Solar Application Circuit
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 TEG Application Circuit
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
      3. 8.2.3 Piezoelectric Application Circuit
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.3 Battery Overvoltage Protection

To prevent rechargeable batteries from being exposed to excessive charging voltages and to prevent over charging a capacitive storage element, the over-voltage (VBAT_OV) threshold level must be set using external resistors. This is also the voltage value to which the charger will regulate the VSTOR/VBAT pin when the input has sufficient power. The VBAT_OV threshold when the battery voltage is rising is given by Equation 2:

Equation 2. bq25570 EQ3_Vbat2_lusah0.gif

The sum of the resistors is recommended to be no higher than 13 MΩ that is, ROV1 + ROV2 = 13 MΩ. Spreadsheet SLUC484 provides help on sizing and selecting the resistors. The overvoltage threshold when battery voltage is decreasing is given by VBAT_OV minus VBAT_OV_HYST. Once the voltage at the battery exceeds VBAT_OV threshold, the boost charger is disabled. The charger will start again once the battery voltage drops by VBAT_OV_HYST. When there is excessive input energy, the VBAT pin voltage will ripple between the VBAT_OV and the VBAT_OV_HYST levels.

CAUTION

If VIN_DC is higher than VSTOR and VSTOR is equal to VBAT_OV, the input VIN_DC is pulled to ground through a small resistance to stop further charging of the attached battery or capacitor. It is critical that if this case is expected, the impedance of the source attached to VIN_DC be higher than 20 Ω and not a low impedance source.