SLUSDE1E September   2018  – November 2024 UCC21540 , UCC21540A , UCC21541 , UCC21542

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
    1. 5.1 Pin Configuration and Functions
    2. 5.2 UCC21542 Pin Functions
  7. 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
  8. 7 Parameter Measurement Information
    1. 7.1 Minimum Pulses
    2. 7.2 Propagation Delay and Pulse Width Distortion
    3. 7.3 Rising and Falling Time
    4. 7.4 Input and Disable Response Time
    5. 7.5 Programmable Dead Time
    6. 7.6 Power-Up UVLO Delay to OUTPUT
    7. 7.7 CMTI Testing
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 VDD, VCCI, and Under Voltage Lock Out (UVLO)
      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 Diode Structure in the UCC2154x
    4. 8.4 Device Functional Modes
      1. 8.4.1 Disable Pin
      2. 8.4.2 Programmable Dead Time (DT) Pin
        1. 8.4.2.1 DT Pin Tied to VCCI
        2. 8.4.2.2 Connecting a Programming Resistor between DT and GND Pins
  10. 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 Designing INA/INB Input Filter
        2. 9.2.2.2 Select Dead Time Resistor and Capacitor
        3. 9.2.2.3 Select External Bootstrap Diode and Its Series Resistor
        4. 9.2.2.4 Gate Driver Output Resistor
        5. 9.2.2.5 Gate to Source Resistor Selection
        6. 9.2.2.6 Estimating Gate Driver Power Loss
        7. 9.2.2.7 Estimating Junction Temperature
        8. 9.2.2.8 Selecting VCCI, VDDA/B Capacitor
          1. 9.2.2.8.1 Selecting a VCCI Capacitor
          2. 9.2.2.8.2 Selecting a VDDA (Bootstrap) Capacitor
          3. 9.2.2.8.3 Select a VDDB Capacitor
        9. 9.2.2.9 Application Circuits with Output Stage Negative Bias
      3. 9.2.3 Application Curves
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Component Placement Considerations
      2. 11.1.2 Grounding Considerations
      3. 11.1.3 High-Voltage Considerations
      4. 11.1.4 Thermal Considerations
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  14. 13Revision History
  15. 14Mechanical, Packaging, and Orderable Information

7.6 Power-Up UVLO Delay to OUTPUT

Whenever the supply voltage VCCI crosses from below the falling threshold VVCCI_OFF to above the rising threshold VVCCI_ON, and whenever the supply voltage VDDx crosses from below the falling threshold VVDDx_OFF to above the rising threshold VVDDx_ON, there is a delay before the outputs begin responding to the inputs. For VCCI UVLO this delay is defined as tVCCI+ to OUT, and has a maximum value of 50 µs. For VDDx UVLO this delay is defined as tVDD+ to OUT, and has a maximum value of 10 µs. TI recommends allowing some margin before driving input signals, to ensure the driver VCCI and VDD bias supplies are fully activated. Figure 7-7 and Figure 7-8 show the power-up UVLO delay timing diagram for VCCI and VDD.

Whenever the supply voltage VCCI crosses below the falling threshold VVCCI_OFF, or VDDx crosses below the falling threshold VVDDx_OFF, the outputs stop responding to the inputs and are held low within ≤2 µs. This asymmetric delay is designed to ensure safe operation during VCCI or VDDx brownouts.

When VCCI goes away but VDDx is present, outputs are held low; when VDDx is gone, outputs are CLAMPED low through the active pull down feature. For more detailed UVLO feature description, please check session Section 8.3.1.

UCC21540 UCC21540A UCC21541 UCC21542 VCCI Power-up UVLO DelayFigure 7-7 VCCI Power-up UVLO Delay
UCC21540 UCC21540A UCC21541 UCC21542 VDDA/B Power-Up UVLO DelayFigure 7-8 VDDA/B Power-Up UVLO Delay