SLUSDS3A March   2020  – January 2024 UCC21739-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Power Ratings
    6. 5.6  Insulation Specifications
    7. 5.7  Safety-Related Certifications
    8. 5.8  Safety Limiting Values
    9. 5.9  Electrical Characteristics
    10. 5.10 Switching Characteristics
    11. 5.11 Insulation Characteristics Curves
    12. 5.12 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Propagation Delay
      1. 6.1.1 Regular Turn-OFF
    2. 6.2 Input Deglitch Filter
    3. 6.3 Active Miller Clamp
      1. 6.3.1 External Active Miller Clamp
    4. 6.4 Under Voltage Lockout (UVLO)
      1. 6.4.1 VCC UVLO
      2. 6.4.2 VDD UVLO
    5. 6.5 OC (Over Current) Protection
      1. 6.5.1 OC Protection with 2-Level Turn-OFF
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Power Supply
      2. 7.3.2  Driver Stage
      3. 7.3.3  VCC and VDD Undervoltage Lockout (UVLO)
      4. 7.3.4  Active Pulldown
      5. 7.3.5  Short Circuit Clamping
      6. 7.3.6  External Active Miller Clamp
      7. 7.3.7  Overcurrent and Short Circuit Protection
      8. 7.3.8  2-Level Turn-off
      9. 7.3.9  Fault ( FLT, Reset and Enable ( RST/EN)
      10. 7.3.10 Isolated Analog to PWM Signal Function
    4. 7.4 Device Functional Modes
  9. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input filters for IN+, IN- and RST/EN
        2. 8.2.2.2 PWM Interlock of IN+ and IN-
        3. 8.2.2.3 FLT, RDY and RST/EN Pin Circuitry
        4. 8.2.2.4 RST/EN Pin Control
        5. 8.2.2.5 Turn-On and Turn-Off Gate Resistors
        6. 8.2.2.6 External Active Miller Clamp
        7. 8.2.2.7 Overcurrent and Short Circuit Protection
          1. 8.2.2.7.1 Protection Based on Power Modules with Integrated SenseFET
          2. 8.2.2.7.2 Protection Based on Desaturation Circuit
          3. 8.2.2.7.3 Protection Based on Shunt Resistor in Power Loop
        8. 8.2.2.8 Isolated Analog Signal Sensing
          1. 8.2.2.8.1 Isolated Temperature Sensing
          2. 8.2.2.8.2 Isolated DC Bus Voltage Sensing
        9. 8.2.2.9 Higher Output Current Using an External Current Buffer
      3. 8.2.3 Application Curves
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 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 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.6 External Active Miller Clamp

Active miller clamp feature is important to prevent the false turn-on while the driver is in OFF state. In applications which the device can be in synchronous rectifier mode, the body diode conducts the current during the deadtime while the device is in OFF state, the drain-source or collector-emitter voltage remains the same and the dV/dt happens when the other power semiconductor of the phase leg turns on. The low internal pull-down impedance of UCC21739-Q1 can provide a strong pulldown to hold the OUTL to VEE. However, external gate resistance is usually adopted to limit the dV/dt. The miller effect during the turn on transient of the other power semiconductor can cause a voltage drop on the external gate resistor, which boost the gate-source or gate-emitter voltage. If the voltage on VGS or VGE is higher than the threshold voltage of the power semiconductor, a shoot through can happen and cause catastrophic damage. The active miller clamp feature of UCC21739-Q1 drives an external MOSFET, which connects to the device gate. The external MOSFET is triggered when the gate voltage is lower than VCLMPTH, which is 2V above VEE, and creates a low impedance path to avoid the false turn on issue.

GUID-B131D264-16DA-48DA-A4C7-6A0DDEA94A47-low.gif Figure 7-4 Active Miller Clamp