SLUSFG9A April   2024  – June 2024 TPS561243 , TPS561246

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 Adaptive On-Time Control and PWM Operation
      2. 6.3.2 Eco-mode Control
      3. 6.3.3 Soft Start and Prebiased Soft Start
      4. 6.3.4 Large Duty Operation
      5. 6.3.5 Current Protection
      6. 6.3.6 Enable Circuit
      7. 6.3.7 Undervoltage Lockout (UVLO) Protection
      8. 6.3.8 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Eco-mode Operation
      2. 6.4.2 FCCM Mode Operation
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Custom Design With WEBENCH® Tools
        2. 7.2.2.2 Output Voltage Resistors Selection
        3. 7.2.2.3 Output Filter Selection
        4. 7.2.2.4 Input Capacitor Selection
        5. 7.2.2.5 Bootstrap Capacitor Selection
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 Custom Design With WEBENCH® Tools
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.2 Eco-mode Control

The TPS561243 is designed with advanced Eco-mode to maintain high light load efficiency. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to a point that the ripple valley touches zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when the zero inductor current is detected. As the load current further decreases, the converter runs into discontinuous conduction mode. The on-time is kept almost the same as in the continuous conduction mode so that discharging the output capacitor with smaller load current to the level of the reference voltage takes a longer time. This action makes the switching frequency lower, proportional to the load current, and keeps the light load efficiency high. Use Equation 1 to calculate the transition point to the light load operation IOUT(LL) current.

Equation 1. IoutLL=12×L×fSW×VIN-VOUT×VOUTVIN