Application Note 2 Revision 1.1

05-11-2018

2500 W full-bridge totem-pole power factor correction using

CoolGaN™

Table of contents

About this document ....................................................................................................................... 1

1 PFC demonstration platform ........................................................................................... 3

1.1 Totem-pole full-bridge PFC ..................................................................................................................... 3

1.2 Schematic and implementation details ................................................................................................. 4

1.2.1 PWM switching frequency .................................................................................................................. 4

1.2.2 PFC inductor design ........................................................................................................................... 4

1.3 Gate driving ............................................................................................................................................. 5

1.4 Layout considerations ............................................................................................................................. 8

1.5 Thermal concept ..................................................................................................................................... 9

1.6 EMI filters ............................................................................................................................................... 10

1.7 Auxiliary power supply .......................................................................................................................... 10

1.8 Control daughter boards....................................................................................................................... 12

1.8.1 Zero crossing detection ................................................................................................................... 13

1.8.2 V

BULK

sensing ..................................................................................................................................... 13

1.8.3 Switch, diode and synchronous sectification signal generation ................................................... 13

1.8.4 Level shifter ...................................................................................................................................... 13

1.8.5 Zero current turn off and zero window comparator ....................................................................... 14

1.8.6 True DCM monitor / enabler ............................................................................................................ 14

1.8.7 Current sensing approach ............................................................................................................... 14

2 Getting started with the hardware .................................................................................. 15

2.1 Basic wiring and connections ............................................................................................................... 15

2.2 Start-up procedure ................................................................................................................................ 18

2.2.1 AC input voltage requirements ........................................................................................................ 19

2.2.2 DC output voltage ............................................................................................................................ 19

3 Measurement results..................................................................................................... 20

3.1 Efficiency measurement ....................................................................................................................... 20

3.2 Gate signal measurements ................................................................................................................... 20

3.3 Start-up .................................................................................................................................................. 24

3.4 AC-line cycle drop-out test .................................................................................................................... 29

3.5 Load steps .............................................................................................................................................. 30

3.6 EMI measurement result ....................................................................................................................... 30

4 Specifications ............................................................................................................... 32

5 Addendum ................................................................................................................... 33

5.1 Schematics of the main board .............................................................................................................. 33

5.1 Schematics of the auxiliary supply daughter board ............................................................................ 35

5.2 Schematics of the control board .......................................................................................................... 36

5.3 Bill of Materials (BOM) ........................................................................................................................... 37

5.3.1 Main board ........................................................................................................................................ 37

5.3.1 Auxillary supply daughter board ..................................................................................................... 39

5.3.2 Controller daughter board ............................................................................................................... 40

5.4 Abbreviations ........................................................................................................................................ 42

6 References ................................................................................................................... 44

7 Revision history ............................................................................................................ 45