SUMMARY

Page

INTRODUCTION

1

The L5991 .......................................................................................................................... 2

Standby Function Description............................................................................................. 3

Standby Operation Analysis ............................................................................................... 4

Standby Function Setup ..................................................................................................... 7

Standby Function and Error................................................................................................ 8

OPTIMISING THE DESIGN FOR MAXIMUM EFFICIENCY AT LIGHT LOAD

Start-up & Self-supply Circuits............................................................................................ 8

Power MOSFET ................................................................................................................. 11

Transformer ........................................................................................................................ 13

Clamp Network ................................................................................................................... 14

Miscellaneous..................................................................................................................... 15

Experimental Results.......................................................................................................... 16

APPENDIX

Flyback Basics.................................................................................................................... 17

Peak Current Mode Control Basics .................................................................................... 20

Light Load Losses Evaluation............................................................................................. 22

AN1049 APPLICATION NOTE

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