SLVSCZ5B July   2016  – October 2018 TPS61230A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
      2.      Efficiency
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Startup
      2. 7.3.2 Enable and Disable
      3. 7.3.3 Under-Voltage Lockout (UVLO)
      4. 7.3.4 Current Limit Operation
      5. 7.3.5 Over Voltage Protection
      6. 7.3.6 Load Disconnect
      7. 7.3.7 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Mode
      2. 7.4.2 PFM Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 TPS61230A 2.5-V to 4.5-V Input, 5-V Output Converter
        1. 8.2.1.1 TPS61230A 5-V Output Design Requirements
        2. 8.2.1.2 TPS61230A 5-V Detailed Design Procedure
          1. 8.2.1.2.1 Programming The Output Voltage
          2. 8.2.1.2.2 Inductor and Capacitor Selection
            1. 8.2.1.2.2.1 Inductor Selection
            2. 8.2.1.2.2.2 Output Capacitor Selection
            3. 8.2.1.2.2.3 Input Capacitor Selection
          3. 8.2.1.2.3 Loop Stability, Feed Forward Capacitor
        3. 8.2.1.3 TPS61230A 5-V Output Application Performance Plots
      2. 8.2.2 Systems Example - TPS61230A with Feed Forward Capacitor for Best Transient Response
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.1.2.3 Loop Stability, Feed Forward Capacitor

The third step is to check the loop stability. The stability evaluation is to look from a steady-state perspective at the following signals:

  • Switching node, SW
  • Inductor current, IL
  • Output ripple, VRipple(OUT)

When the switching waveform shows large duty cycle jitter or the output voltage or inductor current shows oscillations, the regulation loop may be unstable. This is often a result of board layout and/or L-C combination.

The load transient response is another approach to check the loop stability. During the load transient recovery time, VOUT can be monitored for settling time, overshoot or ringing that helps judge the converter’s stability. Without any ringing, the loop has usually more than 45° of phase margin.

As for the heavy load transient applications such as a 2 A load step transient, a feed forward capacitor in parallel with R1 is recommended. The feed forward capacitor increases the loop bandwidth by adding a zero.