SLUSC60B December   2017  – October 2019 UCC28064A


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Simplified Application
  4. Revision History
  5. Description (Continued)
  6. Pin Configuration and Functions
    1.     Pin Functions
  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. 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. Failsafe OVP - Output Over-voltage Protection
        2. Overcurrent Protection
        3. Open-Loop Protection
        4. VCC Undervoltage Lock-Out (UVLO) Protection
        5. Phase-Fail Protection
        6. CS - Open, TSET - Open and Short Protection
        7. Thermal Shutdown Protection
        8. Fault Logic Diagram
    4. 8.4 Device Functional Modes
  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.  Custom Design With WEBENCH® Tools
        2.  Inductor Selection
        3.  ZCD Resistor Selection RZA, RZB
        4.  HVSEN
        5.  Output Capacitor Selection
        6.  Selecting RS For Peak Current Limiting
        7.  Power Semiconductor Selection (Q1, Q2, D1, D2)
        8.  Brownout Protection
        9.  Converter Timing
        10. Programming VOUT
        11. Voltage Loop Compensation
      3. 9.2.3 Application Curves
        1. Input Ripple Current Cancellation with Natural Interleaving
        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. 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

Power Supply Recommendations

The device receives all of its power through the VCC pin. This voltage should be as well regulated as possible through all of the operating conditions of the PFC stage. Consider creating the steady state bias for this stage from a downstream DC:DC stage which will in general be able to provide a bias winding with very well regulated voltage. This strategy will enhance the overall efficiency of the bias generation. A lower efficiency alternative will be to consider a series-connected fixed positive-voltage regulator such as the UA78L15A.

For all normal and abnormal operating conditions it is critically important that VCC remains within the recommended operating range for both Voltage and Input Current. VCC overvoltage may cause excessive power dissipation in the internal voltage clamp and undervoltage may cause inadequate drive levels for power MOSFETs, UVLO events (causing interrupted PFC operation) or inadequate headroom for the various on-chip linear regulators and references.

Note also that the high RMS and peak currents required for the MOSFET gate drives are provided through the device 13.5-V linear regulator, which does not have provision for the addition of external decoupling capacitance. For higher Powers, very high QG power MOSFETs or high switching frequencies, consider using external driver transistors, local to the power MOSFETs. These will reduce the device operating temperature and ensure that the VCC maximum input current rating is not exceeded.

Use decoupling capacitances between VREF and AGND and between VCC and PGND which are as local as possible to the device. These should have some ceramic capacitance which will provide very low ESR. PGND and AGND should ideally be star connected at the control device so that there is negligible DC or high frequency AC voltage difference between PGND and AGND. Use values for decoupling capacitors similar to or a little larger than those used in the EVM.

Pay close attention to start-up and shutdown VCC bias bootstrap arrangements so that these provide adequate regulated bias power as early as possible during power application and as late as possible during power removal. Ensure that these start-up bias bootstrap circuits do not cause unnecessary steady-state power drain.