TIDT304 October   2022

 

  1.   Description
  2.   Features
  3.   Applications
  4. 1Test Prerequisites
    1. 1.1 Voltage and Current Requirements
    2. 1.2 Required Equipment
    3. 1.3 Test Setup
  5. 2Testing and Results
    1. 2.1 Efficiency Graphs
    2. 2.2 Efficiency Data
    3. 2.3 Thermal Images
  6. 3Waveforms
    1. 3.1 Steady State
    2. 3.2 Switching
    3. 3.3 Load Transients

2.3 Thermal Images

The thermal images are shown in Figure 2-3 and Figure 2-4.

The thermal images were collected under the following conditions:

  • Input: 230 VAC
  • Output: 380 V, 1.3 kW
  • Fan: FFB0412EN-00
  • Ambient temperature: 25°C
  • Time: 30 minutes
GUID-20220907-SS0I-LGJD-QB14-N19GT9SCJVGS-low.pngFigure 2-2 Test Setup With Air Flow
GUID-20220906-SS0I-JMNB-ZTZX-CSZ9FFXL1RRK-low.jpgFigure 2-3 Backside of GaN FET Daughter Card
GUID-20220906-SS0I-ZJRV-DPZV-W3HSR3WWKX7X-low.jpgFigure 2-4 PFC Inductor

The thermal simulation conditions and results are shown in Table 2-3, Figure 2-5, and Table 2-4.

Table 2-3 Conditions
FET | Package (× 2) LMG3522R030-Q1 | 12 × 12 mm
System Power 3-kW PFC
Power loss per GaN FET 13.9 W

[target RθJA = (125°C – 55°C) / 13.9 W = < 5°C/W]
Total power loss into heat sink 27.8 W (2 × GaN)
PCB size 40 mm × 37 mm
Heat sink size 35 mm × 26 mm × 9.2 mm
GUID-20220921-SS0I-M78C-CPVB-HDHXPTNZR6TJ-low.png Figure 2-5 Thermal Simulation Result
Table 2-4 Simulation Results
Air Speed (m/s)

TIM k

W/mK

(0.5-mm Thick)

 TA (°C) P (W) GaN 1 (°C) GaN 2 (°C) GaN 1 RθJA (C/W) GaN2 RθJA (C/W)
12 13 55 13.9 97.7 101.8 3.07 3.37

Figure 2-6 shows the heat sink specification.

GUID-20220921-SS0I-L2QX-9VDZ-X6DQVQNZXJX2-low.png Figure 2-6 Heat Sink Specification