SLVSH38 November   2023 TPS61377

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 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 VCC Power Supply
      2. 7.3.2 Enable and Programmable UVLO
      3. 7.3.3 Soft Start
      4. 7.3.4 Switching Frequency
      5. 7.3.5 Programmable Inductor Peak Current Limit
      6. 7.3.6 Shut Down
      7. 7.3.7 Overvoltage Protection
      8. 7.3.8 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operation
      2. 7.4.2 Forced PWM Mode
      3. 7.4.3 Auto PFM Mode
  9. 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 Setting Output Voltage
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Bootstrap Capacitor Selection
        4. 8.2.2.4 Input Capacitor Selection
        5. 8.2.2.5 Output Capacitor Selection
        6. 8.2.2.6 Loop Stability
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
        1. 8.4.2.1 Thermal Considerations
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

7.4.3 Auto PFM Mode

In auto PFM mode , the TPS61377 provides a seamless transition from PWM to PFM operation with smooth on-time/off-time (SOO) mode and enables automatic pulse-skipping mode that provides excellent efficiency over a wide load range. As load current decreasing or VIN rising, the output of the internal error amplifier decreases to lower the inductor peak current, delivering less power to the load. When the output of the error amplifier goes down and reaches a threshold of about 500-mA peak current, the output of the error amplifier is clamped at this value and does not decrease any more, the TPS61377 extends its off-time of the switching period to deliver less energy to the output and regulate the output voltage to the target.

With SOO mode, the TPS61377 keeps the output voltage equal to the setting voltage in PFM mode. In addition, the output voltage ripple is much smaller at light load due to low peak current. Refer to Figure 7-2.

GUID-9F3DEFEB-FAE4-40B5-AAB7-112D3F818EA9-low.svgFigure 7-2 Auto PFM Mode Diagram