Voltage-regulation stations for the distributed power supply system of the ATLAS pixel detector

The innermost part of the ATLAS (A Toroidal LHC ApparatuS) experiment at the LHC (Large Hadron Collider), CERN (Conseil Eurpeenne pour la Recherche Nucleaire), is a pixel detector. To operate the readout electronics and other detector components, a complex power supply and control system is necessary. The paper describes one of the components of which the power supply system is made of: the remotely programmable voltage-regulation station. The specifications, features and characteristics of this custom made electronics sub-rack are described. Particular attention is devoted to the description of the regulator and controller boards. The implemented design solutions allow precise individual adjustment of more than 4000 floating voltages by means of a CAN (Controller Area Network) protocol. The radiation resistance of this electronics made by COTS (components out of the shell) to both gamma and protons is also presented. Statistical analysis of the electrical characteristics of more than 300 boards, equivalent of 4500 voltage channels, is presented.