Realization of serial powering of ATLAS pixel modules

Modern hybrid pixel detectors as will be used for the next generation of high-energy collider experiments like the large hadron collider (LHC) use deep sub-micron technology for readout electronics. Low supply voltages of 2.0 V to 2.5 V and high currents to achieve the desired performance are needed to operate chips in this technology. This high current leads to a significant voltage drop due to the long and low mass supply cables resulting in voltage fluctuations at the chip when the supply current changes. Therefore, the parallel connection of the readout electronics with the power supplies imposes severe constraints on a detector with respect to voltage fluctuations and cable mass. To bypass this problem a new concept of serially connecting modules in a supply chain was developed. The basic idea, the potential risks and ways to minimize these risks are presented. In addition, studies of the implementation of this technology are shown as an alternative to a possible upgrade of the ATLAS pixel detector. In particular, it is shown that the operation of several modules in a supply chain does not affect the stability, the reliability or the performance of the ATLAS pixel modules.