A detector apparatus includes a number of detectors for assigned radiation sources of a computed tomography system, wherein each detector may require a constant input voltage in a range between 900 V and 1200 V. During operation of the detector apparatus, an auxiliary voltage is fed to a high voltage source to supply power to the input terminals on the number of detectors. The high voltage source includes a central first DC-DC converter, to which the auxiliary voltage is fed, and a number of second DC-DC converters arranged downstream of the first DC-DC converter. The first and the second DC-DC converter are based on different power supply topologies, wherein each second DC-DC converter generates the constant input voltage in the predetermined range from a central output voltage provided by the first DC-DC converter and supplies the constant input voltage to a corresponding detector.