JAJU732C June   2019  – July 2022

 

  1.   概要
  2.   Resources
  3.   特長
  4.   アプリケーション
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1  UCC21530
      2. 2.2.2  AMC1311
      3. 2.2.3  AMC3302
      4. 2.2.4  AMC3306M05
      5. 2.2.5  LM76003
      6. 2.2.6  LMZ31707
      7. 2.2.7  OPA320
      8. 2.2.8  ISO7721
      9. 2.2.9  SN6501
      10. 2.2.10 SN6505B
      11. 2.2.11 TMP235
      12. 2.2.12 LMT87
      13. 2.2.13 TL431
      14. 2.2.14 LMV762
      15. 2.2.15 TMS320F280049 C2000 MCU
      16. 2.2.16 TMDSCNCD280049C
    3. 2.3 System Design Theory
      1. 2.3.1 Dual Active Bridge Analogy With Power Systems
      2. 2.3.2 Dual-Active Bridge - Switching Sequence
      3. 2.3.3 Dual-Active Bridge - Zero Voltage Switching (ZVS)
      4. 2.3.4 Dual-Active Bridge - Design Considerations
        1. 2.3.4.1 Leakage Inductor
        2. 2.3.4.2 Effect of Inductance on Current
        3. 2.3.4.3 Phase Shift
        4. 2.3.4.4 Capacitor Selection
        5. 2.3.4.5 Soft Switching Range
        6. 2.3.4.6 Switching Frequency
        7. 2.3.4.7 Transformer Selection
        8. 2.3.4.8 SiC MOSFET Selection
      5. 2.3.5 Loss Analysis
        1. 2.3.5.1 Design Equations
        2. 2.3.5.2 SiC MOSFET and Diode Losses
        3. 2.3.5.3 Transformer Losses
        4. 2.3.5.4 Inductor Losses
        5. 2.3.5.5 Gate Driver Losses
        6. 2.3.5.6 Efficiency
        7. 2.3.5.7 Thermal Considerations
  8. 3Circuit Description
    1. 3.1 Power Stage
    2. 3.2 DC Voltage Sensing
      1. 3.2.1 Primary DC Voltage Sensing
      2. 3.2.2 Secondary DC Voltage Sensing
    3. 3.3 Current Sensing
    4. 3.4 Power Architecture
      1. 3.4.1 Auxiliary Power Supply
      2. 3.4.2 Isolated Power Supply for Sense Circuits
    5. 3.5 Gate Driver
      1. 3.5.1 Gate Driver Circuit
      2. 3.5.2 Gate Driver Bias Power Supply
      3. 3.5.3 Gate Driver Discrete Circuits - Short-Circuit Detection and Two Level Turn Off
  9. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Required Hardware and Software
      1. 4.1.1 Hardware
      2. 4.1.2 Software
        1. 4.1.2.1 Getting Started With Software
        2. 4.1.2.2 Pin Configuration
        3. 4.1.2.3 PWM Configuration
        4. 4.1.2.4 High-Resolution Phase Shift Configuration
        5. 4.1.2.5 ADC Configuration
        6. 4.1.2.6 ISR Structure
    2. 4.2 Test Setup
    3. 4.3 PowerSUITE GUI
    4. 4.4 LABs
      1. 4.4.1 Lab 1
      2. 4.4.2 Lab 2
      3. 4.4.3 Lab 3
      4. 4.4.4 Lab 4
      5. 4.4.5 Lab 5
    5. 4.5 Test Results
      1. 4.5.1 Open-Loop Performance
      2. 4.5.2 Closed-Loop Performance
  10. 5Design Files
    1. 5.1 Schematics
    2. 5.2 Bill of Materials
    3. 5.3 PCB Layout Recommendations
      1. 5.3.1 Layout Prints
    4. 5.4 Altium Project
    5. 5.5 Gerber Files
    6. 5.6 Assembly Drawings
  11. 6Related Documentation
    1. 6.1 Trademarks
  12. 7Terminology
  13. 8About the Author
  14. 9Revision History

2.3.5.5 Gate Driver Losses

The power loss in the gate driver circuit includes the losses in the UCC21530 and losses in the peripheral circuitry like the gate resistors. The power losses consist of the static power loss, which includes quiescent power loss on the driver as well as driver self-power consumption when operating with a certain switching frequency. Values of the static current flowing into the Vcc1 pin (Ivcc1) , VDDA pin (IDDA) , and VDDB pin (IDDB) are extracted from the data sheet.

Equation 33. GUID-77229315-E4A5-4321-A864-DC6C50E45AAA-low.gif

By substituting the values from the data sheet in Equation 33, the result is Pstatic losses of the gate driver around 70 mW. The other component of gate driver loss is the switching operation loss.

Equation 34. GUID-F47D2D81-59CE-4A6B-934B-F1103ADA8576-low.gif

By substituting the value of VDD = 15 V, VSS = –4 V, FSW = 100 kHz, QG = 211 nC in Equation 34, the switching loss comes to 0.8 W. The gate charge for C3M0016120K (primary side MOSFET) is extracted from data sheet. Similarly, for the secondary side, the switching losses are calculated to be approximately 0.33 W. Gate charge, QG, for the C3M0030090K MOSFET is 87 nC and is obtained from the data sheet. Also during turn on and turn off of the MOSFETs, losses occur in the gate resistors. The turn on and turn off gate resistors are 5.11 Ω and 1 Ω. These resistors are chosen to dampen out the oscillations at the gate. The gate driver IC can source 4 A and sink 6-A peak current during the switching process. Taking an average value of this current pulse over a switching cycle, the turn on and turn off losses occurring in the gate resistors is given by Equation 35.

Equation 35. GUID-1597BC70-C8FC-47A7-81C5-BC294A090E12-low.gif

This value comes to 0.5 W across one switch. Thus, the total losses occurring in the four gate driver cards is 10 W.