SLUSDC0D October   2018  – November 2024 UCC21530

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  Timing Requirements
    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 and Pulse Width Distortion
    2. 6.2 Rising and Falling Time
    3. 6.3 Input and Enable Response Time
    4. 6.4 Programable Dead Time
    5. 6.5 Power-Up UVLO Delay to OUTPUT
    6. 6.6 CMTI Testing
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 VDD, VCCI, and Under Voltage Lock Out (UVLO)
      2. 7.3.2 Input and Output Logic Table
      3. 7.3.3 Input Stage
      4. 7.3.4 Output Stage
      5. 7.3.5 Diode Structure in UCC21530-Q1
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable Pin
      2. 7.4.2 Programmable Dead Time (DT) Pin
        1. 7.4.2.1 DT Pin Tied to VCC
        2. 7.4.2.2 DT Pin Connected to a Programming Resistor between DT and GND Pins
  9. 8 Application 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 Designing INA/INB Input Filter
        2. 8.2.2.2 Select Dead Time Resistor and Capacitor
        3. 8.2.2.3 Gate Driver Output Resistor
        4. 8.2.2.4 Estimate Gate Driver Power Loss
        5. 8.2.2.5 Estimating Junction Temperature
        6. 8.2.2.6 Selecting VCCI, VDDA/B Capacitor
          1. 8.2.2.6.1 Selecting a VCCI Capacitor
        7. 8.2.2.7 Other Application Example Circuits
      3. 8.2.3 Application Curves
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Component Placement Considerations
      2. 10.1.2 Grounding Considerations
      3. 10.1.3 High-Voltage Considerations
      4. 10.1.4 Thermal Considerations
    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 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DWK|14
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.3 Gate Driver Output Resistor

The external gate driver resistors, RON/ROFF, are used to:

  1. Limit ringing caused by parasitic inductances/capacitances.
  2. Limit ringing caused by high voltage/current switching dv/dt, di/dt, and body-diode reverse recovery.
  3. Fine-tune gate drive strength, i.e. peak sink and source current to optimize the switching loss.
  4. Reduce electromagnetic interference (EMI).

As mentioned in Section 7.3.4, the UCC21530 has a pull-up structure with a P-channel MOSFET and an additional pull-up N-channel MOSFET in parallel. The combined peak source current is 4 A. Therefore, the peak source current can be predicted with:

Equation 2. UCC21530

where

  • RON: External turn-on resistance,RON=2.2 Ω in this example;.
  • RGFET_INT: Power transistor internal gate resistance, found in the power transistor datasheet.
  • IO+ = Peak source current – The minimum value between 4 A, the gate driver peak source current, and the calculated value based on the gate drive loop resistance.

In this example:

Equation 3. UCC21530

Therefore, the driver peak source current is 2.4 A for each channel. Similarly, the peak sink current can be calculated with:

Equation 4. UCC21530

where

  • ROFF: External turn-off resistance, ROFF=0 in this example;
  • VGDF: The anti-parallel diode forward voltage drop which is in series with ROFF. The diode in this example is an MSS1P4.
  • IO-: Peak sink current – the minimum value between 6 A, the gate driver peak sink current, and the calculated value based on the gate drive loop resistance.

In this example,

Equation 5. UCC21530

Therefore, the driver peak sink current is 3.5 A for each channel.

Importantly, the estimated peak current is also influenced by PCB layout and load capacitance. Parasitic inductance in the gate driver loop can slow down the peak gate drive current and introduce overshoot and undershoot. Therefore, it is strongly recommended that the gate driver loop should be minimized. On the other hand, the peak source/sink current is dominated by loop parasitics when the load capacitance (CISS) of the power transistor is very small (typically less than 1 nF), because the rising and falling time is too small and close to the parasitic ringing period.