15W Buck Boost 1 Scope !" # $ # % & '( ) 2 Table of contents 1 Scope.....................................................................................................................................1 2 Table of contents ...................................................................................................................1 3 Component calculation ..........................................................................................................2 4 Application schematic ...........................................................................................................3 5 CE measurement results according to CISPR25 – Peak detection...........................................4 6 Changing the switching frequency .........................................................................................5 6.1 Increasing the switching frequency .................................................................................5 6.2 Reducing the switching frequency...................................................................................5 7 Conclusions...........................................................................................................................6 390111080326 Rev 002, KHA/DLM Page 1 of 6 11-Sept-08 15W Buck Boost 3 Component calculation * # !" # + !" , # ) -, # . / 00 1 ! '% 2 0 "00 $ ')' ) $ 390111080326 Rev 002, KHA/DLM $ / #. Page 2 of 6 11-Sept-08 15W Buck Boost 4 Application schematic # + - # $ # 3 & '( $ # # # 5 • # • • • , 6 , 2 ) ' # # $ 8 0 / > ? # # $ # ) 7 $# 70+ %2 / # # $ # !" ) , # 9 < / , ) 390111080326 Rev 002, KHA/DLM ) : ! ; 4 . , ! 9:=" <; % > '%) # Page 3 of 6 11-Sept-08 15W Buck Boost 5 CE measurement results according to CISPR25 – Peak detection / # @ - $ # A @ ) # + ' 0 B !16 !16=& C ! @ + 390111080326 Rev 002, KHA/DLM # Page 4 of 6 !16 # $ * # @ # ) 11-Sept-08 15W Buck Boost 6 Changing the switching frequency 6.1 Increasing the switching frequency D ! @ # A "' !16B) 9 $ @ - $ , ' !16); 1 * 6 E # - @ $ + @ # ) ' @ ) / 0 ?!16. , @ :=" < 2 / ! • 7 # - $ # $- - $ # .== , $ , 0 # , # ) 0 !16 ?) /9 - #. , & ' ) ( ? ') * ) * = 2 • = > , ( E - # / / (# , , (' # @ !16( $ # # # # $ # A? )) B 1) ) # 6.2 Reducing the switching frequency / 0 !16 @ -$ # # $ # @ , - )& 1 : '%; - @ -$ # ! + # # # @ 390111080326 Rev 002, KHA/DLM -$ Page 5 of 6 + @ ! - $- #) 11-Sept-08 15W Buck Boost 7 Conclusions , + 4D72 0 E # ) ? $ # # # !" 3 & ' !" # ) / , 390111080326 Rev 002, KHA/DLM # E # $ # - Page 6 of 6 # # 0 , ' ) @ #) 11-Sept-08