SLUSFD2B September   2023  – March 2024 TPSM861252 , TPSM861253 , TPSM861257

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Family Devices
  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 PWM Operation and D-CAP3™ Control Mode
      2. 7.3.2 Eco-mode Control
      3. 7.3.3 Soft Start and Prebiased Soft Start
      4. 7.3.4 Overvoltage Protection
      5. 7.3.5 Frequency
      6. 7.3.6 Large Duty Operation
      7. 7.3.7 Current Protection and Undervoltage Protection
      8. 7.3.8 Undervoltage Lockout (UVLO) Protection
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Eco-mode Operation
      2. 7.4.2 FCCM Mode Operation
  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 Custom Design with WEBENCH® Tools
        2. 8.2.2.2 Output Voltage Resistors Selection
        3. 8.2.2.3 Output Filter Selection
        4. 8.2.2.4 Input Capacitor Selection
        5. 8.2.2.5 Enable Circuit
      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
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 Custom Design with WEBENCH® Tools
    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

7.3.2 Eco-mode Control

The TPSM861252 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 rippled valley touches zero level, which is the boundary between continuous conduction and discontinuous conduction mode. 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 continuous conduction mode so that discharging the output capacitor with smaller load current to the level of the reference voltage takes longer. This event makes the switching frequency lower, proportional to the load current, and keeps the light load efficiency high. Use the below equation to calculate the transition point to the light load operation IOUT(LL) current. The typical inductance is 2.2 uH.

Equation 1. I o u t L L = 1 2 × L × f S W × V I N - V O U T × V O U T V I N