SLVSHJ8 February   2024 TPS61299-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Boost Control Operation
      2. 6.3.2  Version Detection
      3. 6.3.3  Under-voltage Lockout
      4. 6.3.4  Switching Frequency
      5. 6.3.5  Input Current Limit
      6. 6.3.6  Enable and Disable
      7. 6.3.7  Soft-Start Timing
      8. 6.3.8  Down Mode
      9. 6.3.9  Pass-Through Operation
      10. 6.3.10 Output Short-to-Ground Protection
      11. 6.3.11 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Fast Load Transient Mode and Normal Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application-Li-ion Battery to 5V Boost Converter Under Fast Mode
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Maximum Output Current
        2. 7.2.2.2 Inductor Selection
        3. 7.2.2.3 Output Capacitor Selection
        4. 7.2.2.4 Input Capacitor Selection
      3. 7.2.3 Application Curves
    3. 7.3 Typical Application-Li-ion Battery to 5V Boost Converter Under Normal Mode
      1. 7.3.1 Design Requirements
      2. 7.3.2 Application Curves
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
      3. 7.5.3 Thermal Information
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Third-Party Products Disclaimer
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

6.3.9 Pass-Through Operation

The TPS61299-Q1 features down mode and pass-through operation when input voltage is close to or higher than output voltage.

During down mode operation, the device regulates the output voltage to the target voltage even when the input voltage is higher than the output voltage. The control circuit changes the behavior of the rectifying P-channel MOSFET by pulling its gate to input voltage instead of to ground. In this way, the voltage drop across the P-channel MOSFET is increasing as high as to regulate the output voltage.

In pass through mode, the TPS61299-Q1 stops switching and turns on the high-side P-channel MOSFET. The output voltage is the input voltage minus the voltage drop across the DCR of the inductor and the on-resistane (RDS(on)) of the P-channel MOSFET. During pass though operation, the device disables the input current limit function, reverse current protection, and thermal shutdown.

For TPS61299-Q1, with input voltage ramping up, the device goes into down mode when Vin >Vout-35mV. The device stays in down mode until Vin >Vout+100mV and then goes automatically into pass through operation. In the pass through operation, output voltage follows input voltage. The TPS61299-Q1 exits pass though operation and goes back to boost mode when the output voltage drops below the setting target voltage minus 75mV.

GUID-20240131-SS0I-WTGK-CFJB-NPPJDP8B9GB4-low.svg
A. Down mode
B. Pass-through mode
C. Boost mode
Figure 6-4 Mode Transition for TPS61299-Q1