SLVSGE1 March   2022 TPS629206

PRODUCTION DATA  

  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 Mode Selection and Device Configuration (MODE/S-CONF Pin)
      2. 8.3.2 Adjustable VO Operation (External Voltage Divider)
      3. 8.3.3 Selectable VO Operation (VSET and Internal Voltage Divider)
      4. 8.3.4 Smart Enable with Precise Threshold
      5. 8.3.5 Power Good (PG)
      6. 8.3.6 Output Discharge Function
      7. 8.3.7 Undervoltage Lockout (UVLO)
      8. 8.3.8 Current Limit and Short Circuit Protection
      9. 8.3.9 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Forced Pulse Width Modulation (PWM) Operation
      2. 8.4.2 Power Save Mode Operation (Auto PFM/PWM)
      3. 8.4.3 AEE (Automatic Efficiency Enhancement)
      4. 8.4.4 100% Duty-Cycle Operation
      5. 8.4.5 Starting into a Prebiased Load
  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 Programming the Output Voltage
        3. 9.2.2.3 External Component Selection
          1. 9.2.2.3.1 Output Filter and Loop Stability
          2. 9.2.2.3.2 Inductor Selection
          3. 9.2.2.3.3 Capacitor Selection
            1. 9.2.2.3.3.1 Output Capacitor
            2. 9.2.2.3.3.2 Input Capacitor
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 Powering Multiple Loads
      2. 9.3.2 Inverting Buck-Boost (IBB)
  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 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.4 100% Duty-Cycle Operation

The duty cycle of the buck converter operated in PWM mode is given in Equation 10.

Equation 10. GUID-20210112-CA0I-0BT3-NMWK-5L8FMQNJPWJQ-low.gif

The duty cycle increases as the input voltage comes close to the output voltage and the off time of the high-side switch gets smaller. When the minimum off time of typically 80 ns is reached, the TPS629206 scales down its switching frequency while it approaches 100% mode. In 100% mode, the device keeps the high-side switch on continuously as long as the output voltage is below the internal set point. This allows the conversion of small input to output voltage differences. For example, getting the longest operation time of battery-powered applications. In 100% duty cycle mode, the low-side FET is switched off.

The minimum input voltage to maintain output voltage regulation, depending on the load current and the output voltage level, can be calculated as:

Equation 11. GUID-0F1BED33-FB2E-403B-ACCB-46851B313FFE-low.gif

where:

  • IOUT is the output current.
  • RDS(on) is the on-state resistance of the high-side FET.
  • RL is the DC resistance of the inductor used.