SLVSGM3B March   2023  – January 2024 TPS56836 , TPS56837 , TPS56838

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  The Adaptive On-Time Control and PWM Operation
      2. 6.3.2  Mode Selection
      3. 6.3.3  Soft Start and Pre-Biased Soft Start
      4. 6.3.4  Enable and Adjusting Undervoltage Lockout
      5. 6.3.5  Output Overcurrent Limit and Undervoltage Protection
      6. 6.3.6  Overvoltage Protection
      7. 6.3.7  UVLO Protection
      8. 6.3.8  Thermal Shutdown
      9. 6.3.9  Output Voltage Discharge
      10. 6.3.10 Power Good
      11. 6.3.11 Large Duty Operation
    4. 6.4 Device Functional Modes
      1. 6.4.1 Standby Operation
      2. 6.4.2 Eco-mode
      3. 6.4.3 Forced Continuous Conduction Mode
      4. 6.4.4 Out-of-Audio™ Mode
  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 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

6.4.2 Eco-mode

TPS56837 is set to 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 rippled 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 longer time is needed to discharge the output capacitor with smaller load current to the level of the reference voltage. This process makes the switching frequency lower, proportional to the load current, and keeps the light load efficiency high. The transition point to the light load operation IOUT(LL) current can be calculated by Equation 5.

Equation 5. IOUTLL=12×L×Fsw×VIN-VOUT×VOUTVIN