SLUS829G August   2008  – February 2020 UCC2897A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Diagram
  4. 4 Revision History
  5. 5 Device Options
  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 Timing Requirements
    7. 7.7 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 Detailed Pin Descriptions
        1. 8.3.1.1  RDEL
        2. 8.3.1.2  RON
        3. 8.3.1.3  ROFF
        4. 8.3.1.4  VREF
        5. 8.3.1.5  SYNC
        6. 8.3.1.6  GND
        7. 8.3.1.7  CS
        8. 8.3.1.8  RSLOPE
        9. 8.3.1.9  FB
        10. 8.3.1.10 SS/SD
        11. 8.3.1.11 PGND
        12. 8.3.1.12 AUX
        13. 8.3.1.13 OUT
        14. 8.3.1.14 VDD
        15. 8.3.1.15 LINEUV
        16. 8.3.1.16 VIN
        17. 8.3.1.17 LINEOV
      2. 8.3.2 JFET Control and UVLO
      3. 8.3.3 Line Undervoltage Protection
      4. 8.3.4 Line Overvoltage Protection
      5. 8.3.5 Pulse Skipping
      6. 8.3.6 Synchronization
      7. 8.3.7 Gate Drive Connection
      8. 8.3.8 Bootstrap Biasing
    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 Oscillator
        2. 9.2.2.2 Soft Start
        3. 9.2.2.3 VDD Bypass Requirements
        4. 9.2.2.4 Delay Programming
        5. 9.2.2.5 Input Voltage Monitoring
        6. 9.2.2.6 Current Sense and Slope Compensation
      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 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.3.1.8 RSLOPE

A resistor (RSLOPE) connected between this pin and GND (pin 6) sets the amplitude of the slope-compensation current. During the on time of the main gate-drive output (OUT) the voltage across RSLOPE is a representation of the internal-timing-capacitor waveform. As the timing capacitor is being charged, the voltage across RSLOPE also increases, generating a linearly-increasing current waveform. The current provided at the CS pin for slope compensation is proportional to this current flowing through RSLOPE.

Due to the high speed, AC-voltage waveform present at the RSLOPE pin, the parasitic capacitance and inductance of the external-circuit components connected to the RSLOPE pin should be carefully minimized.

For more information on how to program the internal-slope compensation refer to the section of this datasheet.