SLVSGS9E March   2023  – June 2024 TPS61299

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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 System Characteristics
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Boost Control Operation
      2. 7.3.2  Version Detection
      3. 7.3.3  Under-voltage Lockout
      4. 7.3.4  Switching Frequency
      5. 7.3.5  Input Current Limit
      6. 7.3.6  Enable and Disable
      7. 7.3.7  Soft-Start Timing
      8. 7.3.8  Down Mode
      9. 7.3.9  Pass-Through Operation
      10. 7.3.10 Output Short-to-Ground Protection
      11. 7.3.11 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Fast Load Transient Mode and Normal Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application-Li-ion Battery to 5V Boost Converter Under Fast Mode
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Maximum Output Current
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Input Capacitor Selection
      3. 8.2.3 Application Curves
    3. 8.3 Typical Application-Li-ion Battery to 5V Boost Converter Under Normal Mode
      1. 8.3.1 Design Requirements
      2. 8.3.2 Application Curves
    4. 8.4 TPS61299xA Typical Application-Li-ion Battery to 5V Boost Converter Under Normal Mode
      1. 8.4.1 Design Requirements
      2. 8.4.2 Application Curves
    5. 8.5 Power Supply Recommendations
    6. 8.6 Layout
      1. 8.6.1 Layout Guidelines
      2. 8.6.2 Layout Example
    7. 8.7 Thermal Information
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.8 Down Mode

During the start-up, when the input voltage is higher than the output voltage, the TPS61299x/xA works at the down mode to keep the switching. In the Down Mode, the behavior of the rectifying PMOS by pulling its gate to input voltage instead of to ground. In this way, the voltage drop across the PMOS is increasing as high as to regulate the output voltage. The high side PMOS works under saturation area, thus the effciency is much lower than boost mode. The power loss also increases in this mode, which needs to be taken into account for thermal consideration. Moreover, the current limit decreases as well under down mode, with TPS612994 decreasing by 50% and TPS61299 decreasing by 20%.