Serial powering protection for Inner Detector modules One module Strip detectors on a stave A possible ATLAS short-strip lay-out 1 2 3 4 23 24 Stave ASIC Open-circuit fault here Strip detector Hybrid Power (constant current) Stave GND Why? • Failure of one module must not affect the performance of any other module. • Provides the option to switch off selected module(s). How? • Several options exist to short out one module – other modules unaffected. • All operate on the same basic principle of using an electronic shorting switch. Target specifications • Less than 100mV across each module when it is “off”. • Switching one module on/off will not affect its neighbours. • During normal operation (all modules working) protection draws no power. • Extra module components use about 10mm2 hybrid area. • Each module can automatically, independently and very quickly shut down in a fault condition. • The Detector Control System (DCS) will control power to each module. Bonn University, Germany Features • Tailored to pixel detectors. • Separate line from each module to end of stave allows each module voltage to be measured. • Uses an SCR to latch into shorting state on over-voltage. Block diagram Schematic Tests Brookhaven National Laboratory, USA Features • Tailored to strip detectors. • Separate component used for over-voltage and DCS. • One line DCS control. Block diagram Schematic Tests STFC Rutherford Appleton Laboratory, UK Features • Tailored to strip detectors. • One line controller output enables a low-voltage oscillator. A voltage multiplier is used to generate the voltage required to completely switch off the module. Block diagram Schematic Tests Over-voltage protection Over-voltage protection DCS control Iin Voltage multiplier Iin Iin Stave Vp DCS from one wire controller & oscillator 47nF 22nF 22nF 10M 2SB947A BAT54 BZX384-B3V9 To shunt regulator and module To shunt regulator and module BSH103PLP To shunt regulator and module DCS control 100k 2SD1271A SI 1450DH 47nF 22nF 22nF One wire to each module 10k DCS from one wire controller 4V 1k 100k 100k 1nF 1M 10nF Stave GND Iout Iout Iout Simulation Can make small circuits for stave prototypes with commercial devices. Just beginning to investigate how much of circuit can be incorporated in a single chip. Need to understand which processes are available and what are characteristics of available components in those processes (e.g. FET breakdown and turn on thresholds). Switching a strip module off and the effect on its neighbour Markus Cristinziani Andreas Eyring Fabian Huegging Laura Gonella David Lynn James Kierstead Marc Weber Giulio Villani John Matheson Richard Holt • Attractive stand-by/protection solutions have been identified • Overhead (area, number of components & control lines) is small • A 130nm ASIC prototype is in development Richard Holt, Rutherford Appleton Laboratory ACES 2009 March 2009