SLUSEM3B March   2022  – January 2023 UCC21737-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Power Ratings
    6. 6.6  Insulation Specifications
    7. 6.7  Safety Limiting Values
    8. 6.8  Electrical Characteristics
    9. 6.9  Switching Characteristics
    10. 6.10 Insulation Characteristics Curves
    11. 6.11 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Propagation Delay
      1. 7.1.1 Regular Turn-OFF
    2. 7.2 Input Deglitch Filter
    3. 7.3 Active Miller Clamp
      1. 7.3.1 External Active Miller Clamp
    4. 7.4 Undervoltage Lockout (UVLO)
      1. 7.4.1 VCC UVLO
      2. 7.4.2 VDD UVLO
      3. 7.4.3 VEE UVLO
    5. 7.5 Overcurrent (OC) Protection
      1. 7.5.1 OC Protection with Soft Turn-OFF
    6. 7.6 ASC Support
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Power Supply
      2. 8.3.2  Driver Stage
      3. 8.3.3  VCC, VDD, and VEE Undervoltage Lockout (UVLO)
      4. 8.3.4  Active Pulldown
      5. 8.3.5  Short Circuit Clamping
      6. 8.3.6  External Active Miller Clamp
      7. 8.3.7  Overcurrent and Short Circuit Protection
      8. 8.3.8  Soft Turn-off
      9. 8.3.9  Fault (FLT), Reset, and Enable (RST/EN)
      10. 8.3.10 ASC Support and APWM Monitor
    4. 8.4 Device Functional Modes
  9. 9 Applications 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 Input Filters for IN+, IN-, and RST/EN
        2. 9.2.2.2 PWM Interlock of IN+ and IN-
        3. 9.2.2.3 FLT, RDY, and RST/EN Pin Circuitry
        4. 9.2.2.4 RST/EN Pin Control
        5. 9.2.2.5 Turnon and Turnoff Gate Resistors
        6. 9.2.2.6 External Active Miller Clamp
        7. 9.2.2.7 Overcurrent and Short Circuit Protection
          1. 9.2.2.7.1 Protection Based on Power Modules with Integrated SenseFET
          2. 9.2.2.7.2 Protection Based on Desaturation Circuit
          3. 9.2.2.7.3 Protection Based on Shunt Resistor in Power Loop
        8. 9.2.2.8 Higher Output Current Using an External Current Buffer
      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 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Support 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

8.3.3 VCC, VDD, and VEE Undervoltage Lockout (UVLO)

The UCC21737-Q1 implements the internal UVLO protection feature for both input and output power supplies VCC and VDD. When the supply voltage is lower than the threshold voltage, the driver output is held as LOW. The output only goes HIGH when both VCC and VDD are out of the UVLO status. The UVLO protection feature not only reduces the power consumption of the driver itself during low power supply voltage condition, but also increases the efficiency of the power stage. For SiC MOSFET and IGBT, the on-resistance reduces while the gate-source voltage or gate-emitter voltage increases. If the power semiconductor is turned on with a low VDD value, the conduction loss increases significantly and can lead to a thermal issue and efficiency reduction of the power stage. The UCC21737-Q1 implements a 12-V threshold voltage of VDD UVLO, with 800-mV hysteresis; a -3-V threshold voltage of VEE UVLO, with 400-mV hysteresis. This threshold voltage is suitable for both SiC MOSFET and IGBT.

The UVLO protection block features with hysteresis and deglitch filter, which help to improve the noise immunity of the power supply. During the turn-on and turn-off switching transient, the driver sources and sinks a peak transient current from the power supply, which can result in a sudden voltage drop of the power supply. With hysteresis and UVLO deglitch filter, the internal UVLO protection block ignores small noises during the normal switching transients.

The timing diagrams of the UVLO feature of VCC, VDD, and VEE are shown in Figure 7-8, Figure 7-9, and Figure 7-10. The RDY pin on the input side is used to indicate the power-good condition. The RDY pin is open drain. During UVLO condition, the RDY pin is held in low status and connected to GND. Normally the pin is pulled up externally to VCC to indicate the power good.