SLUSC60B December   2017  – October 2019 UCC28064A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application
  4. 4 Revision History
  5. 5 Description (Continued)
  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  Principles of Operation
      2. 8.3.2  Natural Interleaving
      3. 8.3.3  On-Time Control, Maximum Frequency Limiting, Restart Timer and Input Voltage Feed-Forward compensation
      4. 8.3.4  Distortion Reduction
      5. 8.3.5  Zero-Current Detection and Valley Switching
      6. 8.3.6  Phase Management and Light-Load Operation
      7. 8.3.7  Burst Mode Operation
      8. 8.3.8  External Disable
      9. 8.3.9  Improved Error Amplifier
      10. 8.3.10 Soft Start
      11. 8.3.11 Brownout Protection
      12. 8.3.12 Line Dropout Detection
      13. 8.3.13 VREF
      14. 8.3.14 VCC
      15. 8.3.15 System Level Protections
        1. 8.3.15.1 Failsafe OVP - Output Over-voltage Protection
        2. 8.3.15.2 Overcurrent Protection
        3. 8.3.15.3 Open-Loop Protection
        4. 8.3.15.4 VCC Undervoltage Lock-Out (UVLO) Protection
        5. 8.3.15.5 Phase-Fail Protection
        6. 8.3.15.6 CS - Open, TSET - Open and Short Protection
        7. 8.3.15.7 Thermal Shutdown Protection
        8. 8.3.15.8 Fault Logic Diagram
    4. 8.4 Device Functional Modes
  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  Inductor Selection
        3. 9.2.2.3  ZCD Resistor Selection RZA, RZB
        4. 9.2.2.4  HVSEN
        5. 9.2.2.5  Output Capacitor Selection
        6. 9.2.2.6  Selecting RS For Peak Current Limiting
        7. 9.2.2.7  Power Semiconductor Selection (Q1, Q2, D1, D2)
        8. 9.2.2.8  Brownout Protection
        9. 9.2.2.9  Converter Timing
        10. 9.2.2.10 Programming VOUT
        11. 9.2.2.11 Voltage Loop Compensation
      3. 9.2.3 Application Curves
        1. 9.2.3.1 Input Ripple Current Cancellation with Natural Interleaving
        2. 9.2.3.2 Brownout Protection
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Package Option Addendum
    1. 12.1 Packaging Information
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Development Support
        1. 13.1.1.1 Custom Design With WEBENCH® Tools
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.9 Improved Error Amplifier

The voltage error amplifier is a transconductance amplifier. Voltage-loop compensation is connected from the error amplifier output, COMP, to analog ground, AGND. The recommended Type-II compensation network is shown in Figure 24. For loop-stability purposes, the compensation network values are calculated based on small-signal perturbations of the output voltage using the nominal transconductance (gain) of 55 µS.

UCC28064A fig3_lusao7.gifFigure 24. Transconductance Error Amplifier With Typical Compensation Network

To improve the transient response to large perturbations, the error amplifier gain increases by a factor of around 5X when the error amplifier input deviates more than ±5% from the nominal regulation voltage, VSENSEreg. This increase allows faster charging and discharging of the compensation components following sudden load-current increases or decreases.

UCC28064A fig4_lusao7.gif
Basic voltage error amplifier transconductance curve showing small-signal and large-signal gain sections, with maximum current limitations.
Figure 25. Basic Voltage-Error Amplifier Transconductance Curve