Look here for the datasheet on the ic. The first shows ac
waveforms. The last one is a 138 page manual on PWM
switch mode power supplies. Sky.

http://rocky.digikey.com/WebLib/On-S...0NCV3843BV.pdf

http://www.onsemi.com/pub/Collateral/UC3842B.PDF

http://home.eunet.cz/rysanek/pdf/mot-sw.pdf