SLUUCN1C June   2022  – December 2022 UCC28C50 , UCC28C50-Q1 , UCC28C51 , UCC28C51-Q1 , UCC28C52 , UCC28C52-Q1 , UCC28C53 , UCC28C53-Q1 , UCC28C54 , UCC28C54-Q1 , UCC28C55 , UCC28C55-Q1 , UCC28C56H , UCC28C56H-Q1 , UCC28C56L , UCC28C56L-Q1 , UCC28C57H , UCC28C57H-Q1 , UCC28C57L , UCC28C57L-Q1 , UCC28C58 , UCC28C58-Q1 , UCC28C59 , UCC28C59-Q1

 

  1.   Trademarks
  2. 1General Texas Instruments High Voltage Evaluation (TI HV EVM) User Safety Guidelines
  3. 2Description
    1. 2.1 EVM Electrical Performance Specifications
  4. 3Schematic Diagram
  5. 4EVM Setup and Operation
    1. 4.1 Recommended Test Equipment
    2. 4.2 External Connections
      1. 4.2.1 Setup and Connection of Test Equipment
      2. 4.2.2 Power On for the First Time
    3. 4.3 EVM Test Points
  6. 5Performance Data
    1. 5.1  Efficiency Versus Load, 10% to 100% Load
    2. 5.2  Efficiency Versus VIN at 100% Load
    3. 5.3  Power Loss Versus Load, 10% to 100% Load
    4. 5.4  Load Regulation, 10% to 100% Load
    5. 5.5  Light Load Regulation, 0-mA to 200-mA Load
    6. 5.6  Line Regulation, Various Loads
    7. 5.7  Startup Waveforms
    8. 5.8  Shutdown Waveforms
    9. 5.9  Output Voltage Ripple
    10. 5.10 Steady State Switching Waveforms
    11. 5.11 Transient Load Waveforms
    12. 5.12 Over Current and Short Circuit Protections
    13. 5.13 Stability Measurements
    14. 5.14 Thermal Measurements
  7. 6Assembly and Printed Circuit Board (PCB)
  8. 7Bill of Materials (BOM)
  9. 8Revision History

5.14 Thermal Measurements

Test Methodology:

As shown in figure 5-35, the UCC28C56H EVM was placed in a protective enclosure to isolate the high-voltage (VIN > 50V) from test personnel. The enclosure did not provide any forced air movement (i.e. there are no fans). The following thermal results should be considered worst-case due to the dead-air environment. For each load condition, the soak time was 30 – 45 minutes.

The hottest component on the EVM is the transformer. The transformer temperature was taken two ways: (1) by a thermocouple taped directly to the top of the windings (see figure 5-36), and (2) using a thermal camera and black electrical tape placed directly over the thermocouple/windings (see figure 5-37). The two methods provided results within 2 °C of each other. Temperature of the output rectifier diode and switching MOSFET were taken only with the thermal camera. The PCB temperature near the transformer was measured with a thermocouple.

GUID-20220606-SS0I-GHN8-CKDB-8J4MMGGRQDFQ-low.jpg Figure 5-35 UCC28C56H EVM in plexiglass enclosure for HV safety. Virtually no airflow.
GUID-20220606-SS0I-9QLC-THJG-HNPPG0L53VGW-low.jpg Figure 5-36 Thermocouple taped to windings
GUID-20220606-SS0I-HQWP-6SBC-6RCJ55MVVL5P-low.jpg Figure 5-37 Black tape for thermal camera

Transformer Temperature vs Load

Figure 5-38 Transformer temperature vs load
Table 5-1 Thermal Results: VIN = 50 V, 1.3 A, 20 W load
GUID-20220621-SS0I-P2LN-GG3V-QGDGVRVFQ7LT-low.jpg Figure 5-39 Transformer temperature is 55.7°C

Transformer & PCB Temperatures:

  • Thermal camera measurement: 55.7 °C
  • Thermocouple measurement: 53.9 °C
  • Average temperature rise: 54.8 °C
  • PCB temperature: 30.6 °C

Transformer TRISE = 53.9 °C - 30.6 °C = 23.3 °C
GUID-20220621-SS0I-N1NV-WLPK-WGJSBPQ428X1-low.jpg Figure 5-40 Output diode temperature is 43.6°C
GUID-20220621-SS0I-3FPL-MQNJ-FPNGVRBK01M4-low.jpg Figure 5-41 MOSFET temperature is 46.3°C
Table 5-2 Thermal Results: VIN = 800 V, 2.7 A, 40 W load
GUID-20220621-SS0I-D8TH-RFF0-C7RPQTBNP751-low.jpg Figure 5-42 Transformer temperature is 86.7°C

Transformer & PCB Temperatures:

  • Thermal camera measurement: 86.7 °C
  • Thermocouple measurement: 86.2 °C
  • Average temperature rise: 86.5 °C
  • PCB temperature: 37.6 °C

Transformer TRISE = 86.5 °C - 37.6°C = 48.9 °C
GUID-20220621-SS0I-LQX7-JTVJ-8S3Z6PK6LQNG-low.jpg Figure 5-43 Output diode temperature is 61.5°C
GUID-20220701-SS0I-FN2D-MGXQ-4QQBW7PZ9C8W-low.png Figure 5-44 MOSFET temperature is 72.8°C