SLUSE29E May   2020  – February 2024 UCC5350-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Description (continued)
  6. 5 Pin Configuration and Function
  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 for D Package
    7. 6.7  Insulation Specifications for DWV Package
    8. 6.8  Safety-Related Certifications For D Package
    9. 6.9  Safety-Related Certifications For DWV Package
    10. 6.10 Safety Limiting Values
    11. 6.11 Electrical Characteristics
    12. 6.12 Switching Characteristics
    13. 6.13 Insulation Characteristics Curves
    14. 6.14 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Propagation Delay, Inverting, and Noninverting Configuration
      1. 7.1.1 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 Power Supply
      2. 8.3.2 Input Stage
      3. 8.3.3 Output Stage
      4. 8.3.4 Protection Features
        1. 8.3.4.1 Undervoltage Lockout (UVLO)
        2. 8.3.4.2 Active Pulldown
        3. 8.3.4.3 Short-Circuit Clamping
        4. 8.3.4.4 Active Miller Clamp
    4. 8.4 Device Functional Modes
      1. 8.4.1 ESD Structure
  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 IN+ and IN– Input Filter
        2. 9.2.2.2 Gate-Driver Output Resistor
        3. 9.2.2.3 Estimate Gate-Driver Power Loss
        4. 9.2.2.4 Estimating Junction Temperature
      3. 9.2.3 Selecting VCC1 and VCC2 Capacitors
        1. 9.2.3.1 Selecting a VCC1 Capacitor
        2. 9.2.3.2 Selecting a VCC2 Capacitor
        3. 9.2.3.3 Application Circuits with Output Stage Negative Bias
      4. 9.2.4 Application Curve
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 PCB Material
  13. 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 Certifications
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Support Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  14. 13Revision History
  15. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2.3 Estimate Gate-Driver Power Loss

The total loss, PG, in the gate-driver subsystem includes the power losses (PGD) of the UCC5350-Q1 device and the power losses in the peripheral circuitry, such as the external gate-drive resistor.

The PGD value is the key power loss which determines the thermal safety-related limits of the UCC5350-Q1 device, and it can be estimated by calculating losses from several components.

The first component is the static power loss, PGDQ, which includes quiescent power loss on the driver as well as driver self-power consumption when operating with a certain switching frequency. The PGDQ parameter is measured on the bench with no load connected to the OUT pins at a given VCC1, VCC2, switching frequency, and ambient temperature. In this example, VCC1 is 3.3V and VCC2 is 18 V. The current on each power supply, with PWM switching from 0 V to 3.3 V at 150 kHz, is measured to be ICC1 = 1.67 mA and ICC2 = 1.11 mA . Therefore, use Equation 5 to calculate PGDQ.

Equation 5. GUID-4B7C5E30-96C9-4E29-8AD0-28ED056BA16A-low.gif

The second component is the switching operation loss, PGDO, with a given load capacitance which the driver charges and discharges the load during each switching cycle. Use Equation 6 to calculate the total dynamic loss from load switching, PGSW.

Equation 6. GUID-7FD73D46-43A4-4F19-A527-9269775123EA-low.gif

where

  • QG is the gate charge of the power transistor at VCC2.

So, for this example application the total dynamic loss from load switching is approximately 340 mW as calculated in Equation 7.

Equation 7. GUID-77445121-B24D-4663-AB43-D076A7CAD1A2-low.gif

QG represents the total gate charge of the power transistor and is subject to change with different testing conditions. The UCC5350-Q1 gate-driver loss on the output stage, PGDO, is part of PGSW. PGDO is equal to PGSW if the external gate-driver resistance and power-transistor internal resistance are 0 Ω, and all the gate driver-loss will be dissipated inside the UCC5350-Q1. If an external turn-on and turn-off resistance exists, the total loss is distributed between the gate driver pull-up/down resistance, external gate resistance, and power-transistor internal resistance. Importantly, the pull-up/down resistance is a linear and fixed resistance if the source/sink current is not saturated to 10 A, however, it will be non-linear if the source/sink current is saturated. The gate driver loss will be estimated in the case in which it is not saturated as given in Equation 8.

Equation 8. P G D O = P G S W 2 R O H | | R N M O S R O H | | R N M O S + R G O N + R G F E T _ I n t + R O L R O L + R G O F F + R G F E T _ I n t

In this design example, all the predicted source and sink currents are less than 10 A, therefore, use Equation 9 to estimate the gate-driver loss.

Equation 9. GUID-C3C0724D-AE0A-4D17-AF28-D13E29014532-low.gif

where

  • VOUTH/L(t) is the gate-driver OUT pin voltage during the turnon and turnoff period. In cases where the output is saturated for some time, this value can be simplified as a constant-current source (10 A at turnon and turnoff) charging or discharging a load capacitor. Then, the VOUTH/L(t) waveform will be linear and the TR_Sys and TF_Sys can be easily predicted.

Use Equation 10 to calculate the total gate-driver loss dissipated in the UCC5350-Q1 gate driver, PGD.

Equation 10. GUID-7EDB6B03-5BD6-47FC-A396-F2980C345A49-low.gif