SLUSEM9A September   2022  – June 2024 UCC21755-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 Limiting Values
    8. 5.8  Electrical Characteristics
    9. 5.9  Switching Characteristics
    10. 5.10 Insulation Characteristics Curves
    11. 5.11 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Propagation Delay
      1. 6.1.1 Non-Inverting and Inverting Propagation Delay
    2. 6.2 Input Deglitch Filter
    3. 6.3 Active Miller Clamp
      1. 6.3.1 Internal On-Chip Active Miller Clamp
    4. 6.4 Undervoltage Lockout (UVLO)
      1. 6.4.1 VCC UVLO
      2. 6.4.2 VDD UVLO
    5. 6.5 Desaturation (DESAT) Protection
      1. 6.5.1 DESAT Protection with Soft 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  Internal Active Miller Clamp
      7. 7.3.7  Desaturation (DESAT) Protection
      8. 7.3.8  Soft 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 Overcurrent and Short Circuit Protection
        7. 8.2.2.7 Isolated Analog Signal Sensing
          1. 8.2.2.7.1 Isolated Temperature Sensing
          2. 8.2.2.7.2 Isolated DC Bus Voltage Sensing
        8. 8.2.2.8 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 Device Support
      1. 11.1.1 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

7.3.9 Fault (FLT), Reset and Enable (RST/EN)

The FLT pin of UCC21755-Q1 is open drain and can report a fault signal to the DSP/MCU when the fault is detected through the DESAT pin. The FLT pin is pulled down to GND after the fault is detected, and is held low until a reset signal is received from RST/EN. The device has a fault mute time tFLTMUTE, within which the device ignores any reset signal.

The RST/EN is pulled down internally by a 50-kΩ resistor, and is thus disabled by default when this pin is floating. It must be pulled up externally to enable the driver. The pin has two purposes:

  • To reset the FLT pin. If the RST/EN pin is pulled low for more than tRSTFIL after the mute time tFLTMUTE, then the fault signal is reset and FLT returns to a high impedance state upon the next rising edge applied to the RST/EN pin.
  • To enable and shut down the device. If the RST/EN pin is pulled low for longer than tRSTFIL, the driver is disabled and OUTL is activated to pull down the gate of the IGBT or SiC MOSFET. The pin must be pulled up externally to enable the part; otherwise, the device is disabled by default.