SLUSD05B October   2017  – August 2018 UCC27710

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Schematic
    1.     Typical Propagation Delay Comparison
  5. 5 Revision History
  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 Dynamic Electrical Characteristics
    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 VDD and Under Voltage Lockout
      2. 8.3.2 Input and Output Logic Table
      3. 8.3.3 Input Stage
      4. 8.3.4 Output Stage
      5. 8.3.5 Level Shift
      6. 8.3.6 Low Propagation Delays and Tightly Matched Outputs
      7. 8.3.7 Parasitic Diode Structure
    4. 8.4 Device Functional Modes
      1. 8.4.1 Minimum Input Pulse Operation
      2. 8.4.2 Output Interlock and Dead Time
      3. 8.4.3 Operation Under 100% Duty Cycle Condition
      4. 8.4.4 Operation Under Negative HS Voltage Condition
  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 Selecting HI and LI Low Pass Filter Components (RHI, RLI, CHI, CLI)
        2. 9.2.2.2 Selecting Bootstrap Capacitor (CBOOT)
        3. 9.2.2.3 Selecting VDD Bypass/Holdup Capacitor (CVDD) and Rbias
        4. 9.2.2.4 Selecting Bootstrap Resistor (RBOOT)
        5. 9.2.2.5 Selecting Gate Resistor RON/ROFF
        6. 9.2.2.6 Selecting Bootstrap Diode
        7. 9.2.2.7 Estimate the UCC27710 Power Losses (PUCC27710)
        8. 9.2.2.8 Estimating Junction Temperature
        9. 9.2.2.9 Operation With IGBT's
      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 Related Links
    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

Package Options

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

9.2.2.2 Selecting Bootstrap Capacitor (CBOOT)

The bootstrap capacitor should be sized to have more than enough energy to drive the gate of FET Q1 high, and maintain a stable gate drive voltage for the power transistor.

The total charge needed per switching cycle can be estimated with:

Equation 1. UCC27710 qu1_slusdo5.gif

This design example targets a boot capacitor ripple voltage of 0.5 V. Therefore, the absolute minimum CBOOT requirement is:

Equation 2. UCC27710 qu2_slusdo5.gif

In practice, the value of CBOOT needs to be greater than the calculated value. This allows for capacitance shift from DC bias and temperature, and also skipped cycles that occur during load transients. For this design example a 220-nF capacitor was chosen for the bootstrap capacitor.

Equation 3. UCC27710 qu3_slusdo5.gif