SLVSD38C November   2015  – August 2021 TPS61089

PRODMIX  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Undervoltage Lockout (UVLO)
      2. 8.3.2 Enable and Disable
      3. 8.3.3 Soft Start
      4. 8.3.4 Adjustable Switching Frequency
      5. 8.3.5 Adjustable Peak Current Limit
      6. 8.3.6 Overvoltage Protection
      7. 8.3.7 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operation
        1. 8.4.1.1 Forced PWM Mode
        2. 8.4.1.2 PFM Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Setting Switching Frequency
        3. 9.2.2.3 Setting Peak Current Limit
        4. 9.2.2.4 Setting Output Voltage
        5. 9.2.2.5 Inductor Selection
        6. 9.2.2.6 Input Capacitor Selection
        7. 9.2.2.7 Output Capacitor Selection
        8. 9.2.2.8 Loop Stability
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
      1. 11.2.1 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. 12.1.2.1 Custom Design With WEBENCH® Tools
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.1.1 Forced PWM Mode

In forced PWM mode, the TPS610891 keeps the switching frequency unchanged in light load condition. When the load current decreases, the output of the internal error amplifier decreases as well to keep the inductor peak current down, delivering less power from input to output. When the output current further reduces, the current through the inductor will decrease to zero during the off-time. The high-side N-MOSFET is not turned off even if the current through the MOSFET is zero. Thus, the inductor current changes its direction after it runs to zero. The power flow is from output side to input side. The efficiency will be low in this mode. But with the fixed switching frequency, there is no audible noise and other problems which might be caused by low switching frequency in light load condition.