Abstract
Serial powering features the upcoming phase II HL-LHC upgrade in the ATLAS and CMS experiment. The conventional voltage based powering approach with parallel placed modules results in low powering efficiency. In addition restricted space requirements, radiation tolerance and high magnetic fields make the design of a suitable DC/DC-converter challenging. To ensure that future DC/DC converters can tolerate high radiation doses at reduced space requirements, a high-frequency switching stage with up to 4 stacked core devices with a related biasing circuit for the implementation in inductive DC/DC-converters was considered and successfully verified in a first prototype.