Photodetector power supply system for the CMS hadron calorimeter

The power supply system developed for the hybrid photodiodes used as photodetectors in the hadron calorimeter of the Compact Muon Solenoid (CMS) experiment at LHC in CERN is described. The system includes about 500 channels, with two different voltage outputs on each channel, one high-voltage output up to 14000 V and one bias-voltage output up to 200 V. All output voltages are floating to facilitate single-point ground configuration. The system is computer controlled and ready to be interconnected with the CMS slow-control facility.