TIDT256A March   2022  – March 2022

 

  1.   Description
  2.   Features
  3.   Applications
  4. 1Test Prerequisites
    1. 1.1 LM5156-Q1
      1. 1.1.1 Loading LM5156-Q1
      2. 1.1.2 LM5156-Q1 SEPIC Bode Loop Testing
    2. 1.2 Loading UCC14240-Q1
    3. 1.3 UCC5870-Q1 and UCC5870-Q1 EVM GUI
    4. 1.4 Voltage and Current Requirements
    5. 1.5 Required Equipment
    6. 1.6 Considerations
    7. 1.7 Dimensions
  5. 2Testing and Results
    1. 2.1 SEPIC Efficiency Graphs
    2. 2.2 SEPIC Efficiency Data
    3. 2.3 SEPIC Bode Plots
    4. 2.4 Thermal Images
  6. 3Waveforms
    1. 3.1 SEPIC Switching
    2. 3.2 SEPIC Output Voltage Ripple
    3. 3.3 SEPIC Load Transients
    4. 3.4 SEPIC Start-Up Sequence
    5. 3.5 Isolated Bias Supply Start Up and Shutdown
    6. 3.6 Isolated Gate Drive

1 Test Prerequisites

This section provides the testing guide used in the detailed testing of the SEPIC and in verification of the overall operation of the board.

Table 1-1 and Table 1-2 detail the PMP22817 headers and test points.

Table 1-1 PMP22817 Headers
HeaderDescription
J1VIN to LM5156-Q1 SEPIC: 6 V to 42 V: Main power input
J2Vbias: 3.3 V to 5 V
J5Remove to power up the LM5156-Q1 SEPIC alone. Install to power all devices.
J3Digital I/O on UCC5870-Q1. The UCC5870-Q1 EVM programmer can be connected to this header to use the UCC5870-Q1 EVM GUI to test the UCC5870-Q1 with a plug-in PMP22817-adapterA board. For more information, see Section 1.3.
J4Optional analog inputs to UCC5870-Q1 referenced to target SiC source or IGBT emitter
Table 1-2 Test Points and Test Point Descriptions
Test PointDescription
TP1VIN
TP2+15-V output from UCC14240-Q1
TP324-V output from LM5156-Q1 TP3 used as VOUT for bode plot or loop stability of LM5156-Q1 SEPIC
TP4, TP10Ground, primary
TP10 used as ground for bode plot or loop stability of LM5156-Q1 SEPIC
TP5, TP11Ground, secondary
TP6Power good pin on UCC14240-Q1
TP7ENA pin on UCC14240-Q1
TP8Power good pin on LM5156-Q1, modified to be used as injection point for bode plot to evaluate loop stability
TP9–5-V output from UCC14240-Q1
TP12LM5156-Q1 switch node
  1. Powering the board

    Two supplies are needed to power PMP22817, VIN and Vbias. VIN must be in the range of 9 V to 18 V. Vbias must be in the range of 3.3 V to 5 V. The order in which VIN and Vbias are supplied and removed is not important.

  2. Once the board is properly powered up

    Once VIN and Vbias are supplied, then VIN is present on TP1, the switch node on TP12 is switching at 445 kHz, TP3 measures 24 V, and 20 V is present between TP2 and TP9. TP6 reads high.