In2001,CSRpowersupplysystemmadeagreatprogress.ThreeprototypesweredesignedforCSRquadrupleandcorrectmagnet.Threedifferentcompaniesprovidedthethreeprototypes,butthesamecircuit-chopperwereemployed.ThesimplifieddiagramisshowedinFig.1.Allpulsedswitchingpowersupplyprototypesweretestedsuccessfullybeforetheendof2001.