Speaker
Description
Summary
Serial powering is one of the few practical approaches to distribute power to the SLHC inner trackers with a minimum volume of cables. A number of integrated test structures (supermodules) with serial powering circuitry have been built and investigated over the last years with very promising results. The serial powering circuitry (shunt regulator, shunt transistors and LVDS buffers for AC coupling) was so far based on discrete commercial electronics.
To overcome this limitation in radiation-hardness and real-estate, various serial powering and power management blocks have been implemented in the first version of the ABCN-25 chip. In addition a dedicated serial powering chip, the serial powering interface (SPi) became available. Both ABCN-25 and SPi are realized in 0.25 um CMOS processes.
With these chips three complementary serial powering architectures can be realized. In one architecture the SPi regulator and shunt transistor act as a local power supply on the hybrid and the ABCN-25 internal shunt regulators are not used. This is conceptually the simplest implementation. It requires a robust shunt transistor layout. In another architecture, the SPi shunt regulator controls not a single shunt transistor but distributed shunt transistors in each ABCN-25. Finally, in a third architecture, SPi is not used and the shunt regulators and transistors implemented in ABCN-25 are operated in parallel.
These architectures are implemented on conventional copper Kapton flex hybrid prototypes with up to 20 ABCN-25 chips each. The hybrids were designed at Liverpool University for R&D on the ATLAS SLHC short strip tracker.
After a brief discussion of the architectures and their theoretical features, the characterization results will be presented and discussed. This includes regulator output voltage noise, dynamic impedance, and hybrid noise and noise occupancy as a function of temperature and current. Depending on the status of the measurements at the time of the conference, results on a full module or with a limited number of hybrids in series will be shown as well.
