Thermal Analysis and PCB Design for GaN Power Transistor

Pedro A. Rivera CURENT REU

Final presentation 7/23/2015

University of Tennessee

Background

2

• Prototype power inverter

- Smaller

- Efficient

• GaN power transistor

- High frequency switching

- Low on-resistance

- Operation in high temperatures

• Effects of high temperatures

- Material wear down

- Efficiency

Applications

3

• Electric/hybrid vehicles

• Solar energy

• Wind energy industry

• Domestic/commercial

• Military

Configuration

4

• Replace GaN transistor with resistor

• Experimental PCB design

- Thermal vias

- Bottom heat sink

Taken from GaN systems app note

Objective

5

• Analyze heat dissipation of resistors and heat sink temperature

• Compare different PCB cooling designs • Find the best cooling design

Method

6

Experimental Simulation Theoretical

GaN die

Heat sink

• Obtain data from:

- Resistor

- Heat sink

• FEMM software

- Materials

- Measurements

• Calculate thermal resistance

Results

7

Design #1

0 2 4 6 8 10 12 14 16 18 20280290300310320330340350360370

Comparison of experimental resistor temper-ature for Design #1

ExperimentalSimulation Design #1Theoretical Design #1

Power (W)

Tem

pera

ture

(˚K)

• Experimental results match well simulation and theoretical results

Results

8

0 2 4 6 8 10 12 14 16 18 20300350400450500550600650700750

Comparison of experimental resistor temperature for Design #2

ExperimentalSimulation Design #2Theoretical Design #2

Power (W)

Tem

pera

ture

(˚K)

Design #2

• Not much area under heat source • Higher thermal resistance

Results

9

0 2 4 6 8 10 12 14 16 18 20300350400450500550600650700750

Comparison of experimental resistor temper-ature for Design #3

Experimental Simulation Design #3Theoretical Design #3

Power (W)

Tem

pera

ture

(˚K)

Design #3

• Improves design #2

Conclusion/Future work

10

• The use of thermal vias and heat sink on the bottom was the best design

• The farther away the heat sink from the heat source the worst the cooling will be

• Results can be used for comparison in future designs

• Create new designs to compare

• Use software with three dimensional viewing

Acknowledgements

This work was supported primarily by the ERC Program of the National Science Foundation and DOE under NSF Award Number EEC-1041877.

Other US government and industrial sponsors of CURENT research are also gratefully acknowledged.

11

Questions and Answers

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