TIDUF22 January   2023

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1  6-W Auxiliary Power Supply
      2. 2.2.2  AC Input Current Sensing
      3. 2.2.3  DC Bus Voltage Sensing
      4. 2.2.4  AC Input Voltage Sensing
      5. 2.2.5  GaN Driving
      6. 2.2.6  Inrush Current Protection at Powering On
      7. 2.2.7  Overcurrent Protection
      8. 2.2.8  AC Input Undervoltage Protection
      9. 2.2.9  DC Bus Overvoltage Protection
      10. 2.2.10 GaN Temperature Monitor and Protection
      11. 2.2.11 Heat Sink Temperature Monitor and Protection
      12. 2.2.12 UART Heartbeat Report
      13. 2.2.13 Motor Control Interface
    3. 2.3 Highlighted Products
      1. 2.3.1 LMG352xR030
      2. 2.3.2 TMS320F28002x
      3. 2.3.3 UCC2871x
      4. 2.3.4 TLV906x
      5. 2.3.5 TPS54308
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements and Assembly
      1. 3.1.1 Test Equipment Requirements
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
    4. 3.4 Test Results
      1. 3.4.1 Test Procedures
        1. 3.4.1.1 Test Procedures Under 90 VAC
        2. 3.4.1.2 Test Procedures Under 220 VAC
    5. 3.5 Performance Data: Efficiency, iTHD, and Power Factor
    6. 3.6 Functional Waveforms
      1. 3.6.1  Test Under 90 VAC, 800-Ω Load
      2. 3.6.2  Power-On Sequence Test Under 220 VAC
      3. 3.6.3  Waveform With Heavy Load
      4. 3.6.4  Buck Auxiliary Power Supply Tests
      5. 3.6.5  AC Drop Test
      6. 3.6.6  GaN Switching Performance
      7. 3.6.7  Thermal Test
      8. 3.6.8  Power-Off Sequence
      9. 3.6.9  Surge Test
      10. 3.6.10 Conducted Emission Test
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Documentation Support
    3. 4.3 Support Resources
    4. 4.4 Trademarks
  10. 5About the Author

2 System Overview

This system uses the TI C2000 TMDSCNCD280025C controlCARD as the controller, an independent GaN daughter card with the LMG3522030 provides the fast switching leg, and the diode bridge acts as slow switching leg. Circuit design is simplified since the system reference point is DC bus minus.

A UCC28710 high-voltage buck power supply is implemented to provide 15-V auxiliary voltage rails. This design also uses a single main heat sink, providing easy attachment of all power devices.

Using the features of TMS320F280025C and GaN, this design implements full hardware and software protections, including input undervoltage protection (UVP), overvoltage protection (OVP), overcurrent protections (OCP) (with both one-time-shot and cycle-by-cycle), and GaN and heat sink overtemperature protection (OTP). These protections provide for a robust PFC design.

A separated filter board is designed, so electromagnetic interference (EMI) and electromagnetic compatibility (EMC) performance can be evaluated with different filters.

An isolated UART communication is implemented to report the board working status summary to the host computer periodically – like a heartbeat – providing an easy-to-understand board status.