October 2, 2013 11:28 WSPC - Proceedings Trim Size: 9in x 6in Final˙Paper 1 POWER SUPPLY SYSTEM FOR THE ATLAS EXPERIMENT: DESIGN SPECIFICATIONS, IMPLEMENTATION, TEST AND FIRST RESULTS * M. LAZZARONI ** Dipartimento di Fisica, Universit´ a degli Studi di Milano Via Celoria, 16 - 20133 Milan, Italy and I.N.F.N. Milano, Via Celoria, 16 - 20133 Milan, Italy ** E-mail: massimo.lazzaroni@unimi.it www.unimi.it M. CITTERIO and S. LATORRE I.N.F.N. Milano, Via Celoria, 16 - 20133 Milan, Italy A. LANZA I.N.F.N. Pavia, Via Bassi, 6 - 27100 Pavia, Italy P. COVA and N. DELMONTE Dipartimento di Ingegneria Informazione, University of Parma Viale G.P. Usberti 181/A - 43124 Parma, Italy and I.N.F.N. Pavia, Via Bassi, 6 - 27100 Pavia, Italy F. GIULIANI Dipartimento di Ingegneria Informazione, University of Parma Viale G.P. Usberti 181/A - 43124 Parma, Italy The planned upgrade of instrumentation sensitivity in the ATLAS experiment of the Large Hadron Collider (LHC), at CERN, calls for a new type of power distribution architecture. Moreover, power supplies require DC-DC power con- * This work is supported by I.N.F.N. Italy Apollo collaboration.