SLVSDV6C November   2017  – November 2019 TPS62821 , TPS62822 , TPS62823

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Schematic space space space space
      2.      Efficiency vs Output Current space
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin 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 Enable / Shutdown and Output Discharge
      2. 8.3.2 Soft-Start
      3. 8.3.3 Power Good (PG)
      4. 8.3.4 Undervoltage Lockout (UVLO)
      5. 8.3.5 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Pulse Width Modulation (PWM) Operation
      2. 8.4.2 Power Save Mode (PSM) Operation
      3. 8.4.3 Minimum Duty Cycle and 100% Mode Operation
      4. 8.4.4 Current Limit and Short Circuit Protection
  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 the Adjustable Output Voltage
        3. 9.2.2.3 Feed-forward Capacitor Selection
        4. 9.2.2.4 Output Filter Selection
        5. 9.2.2.5 Inductor Selection
        6. 9.2.2.6 Output Capacitor Selection
        7. 9.2.2.7 Input Capacitor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.4.3 Minimum Duty Cycle and 100% Mode Operation

There is no limitation for small duty cycles, since even at very low duty cycles the switching frequency is reduced as needed to always ensure a proper regulation.

If the output voltage level comes close to the input voltage, the device enters 100% mode. While the high-side switch is constantly turned on, the low-side switch is switched off. The difference between VIN and VOUT is determined by the voltage drop across the high-side FET and the dc resistance of the inductor. The minimum VIN that is needed to maintain a specific VOUT value is estimated as:

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Equation 3. TPS62821 TPS62822 TPS62823 SLVSDV6_eqvinmin.gif

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