1. 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 March 2009