List of figures

UM1063

4/32

DocID018573 Rev 2

List of figures

Figure 1.

EVALPM8803-FLY demonstration kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figure 2.

Demonstration kit schematic: detail of the PoE+ input section

including data transformer, diode bridges, protection, and optional CM choke . . . . . . . . . . 6

Figure 3.

Demonstration kit schematic: detail of the PoE+ section based

on flyback topology with synchronous rectification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 4.

Assembly view: top layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 5.

Assembly view: bottom layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 6.

Top layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 7.

Inner layer 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 8.

Inner layer 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 9.

Bottom layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 10.

Efficiency measurements at 48 V input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 11.

DC-DC only efficiency measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 12.

Overall efficiency measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 13.

Efficiency measurements at 48 V input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 14.

DC-DC only efficiency measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 15.

Overall efficiency measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 16.

Startup from an IEEE 802.3af injector with 2 A load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 17.

Startup from an IEEE 802.3at injector with 4 A load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 18.

Switching between PoE and auxiliary source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 19.

Primary side power MOSFET waveforms at 0 A load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 20.

Primary side power MOSFET waveforms at 4 A load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 21.

Details of primary side power MOSFET waveforms at 4 A load . . . . . . . . . . . . . . . . . . . . . 26

Figure 22.

Secondary side power MOSFET waveforms at 0 A load . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Figure 23.

Secondary side power MOSFET waveforms at 4 A load . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 24.

Effect of a 12 V line transient on the converter at 4 A load. . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 25.

Effect of a 12 V line transient on the converter at 0 A load. . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 26.

Response of the converter to a 2 A - 4 A load transient . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 27.

Response of the converter to a 0 A - 4 A load transient . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 28.

Output ripple measurement at 4 A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 29.

Output ripple measurement at 4 A with infinite persistence . . . . . . . . . . . . . . . . . . . . . . . . 30