DC-DC Conversion Powering Schemes for the CMS Tracker Upgrade

The CMS experiment foresees upgrades of its silicon pixel and strip detectors for the luminosity upgrade of the Large Hadron Collider (LHC), CERN. Due to an increase in the number of readout channels and higher complexity, larger currents will have to be provided to the detector. Since cable channels are difficult to access and space for cables is limited, this would lead to excessively large resistive power losses in the supply cables, which increase with the current squared. CMS has therefore chosen a novel powering scheme based on DC-DC converters, which allows power to be delivered at a higher voltage and consequently lower current. The development of low-mass, low-noise DC-DC converters for application in CMS is presented, including studies of switching noise, magnetic emissions and power efficiency as well as system tests with silicon strip and pixel modules. A scheme for the integration of DC-DC converters in the silicon pixel detector, currently foreseen to be exchanged around 2016, will be discussed.