Serial Powering - Protection Purpose Protect the stave Assure supply of power to a serial powered...

Serial Powering - Protection

Purpose

Protect the staveAssure supply of power to a serial powered chain of modules when one member of the chain fails

Control the staveAllow power to arbitrary selection of modules

Richard Holt – Rutherford Appleton LaboratoryATLAS SCT SP protection options

January 2009

1

Why add protection?

2

Wire bonding failure

Power failure modes

Noisy module

Open circuit module


January 2009

Without protection, one failed module can adversely affect the operation of all other modules on staveDemonstration staves are very reliable - Protection is not strictly necessary

How to add protection?

3

Short out affected module(s)

-- Switch on --Short out and disable this

module

One module out-of-service


January 2009

The switch should respond to module over-voltage and to DCS control

Issues to address

4

How does the protection do its job?Is automatic protection required?How fast must the protection react?Is DCS control/reporting required? (yes)How is the protection controlled?Switching must not affect the rest of the SP chain?Where should the switch be placed? (hybrid)Quantitative estimate of failure rate?What extra complexity can we justify?

Is protection needed for other powering configurations?

But…Circuit options default state connections

Feedback from hybrid current/voltage

Reaction time

Implementation requirements AC coupling

Automatic and/or DCS

Transient effects on problem &/or power-up

Bus-cable or hybrid

Numerical failure analysis

Switch failure modes, fail safe, mass, possibility of common mode failure, monitoring


January 2009

Note that independent module voltage monitoring may be available through the shunt regulator device if using an “intelligent” component such as SPi, but this may not be possible if there is a an open-circuit module. However, it may be possible to identify a faulty module by switching all modules off, then each one on in turn.

Qualitative target specification

5

DCS should be able to switch off (short-out) selected modulesResidual voltage (when ‘off’) < 100mVMinimise number of components, area of components and bus-cable linesPosition on hybrid is acceptableOver-voltage & over-current automatic protection is desirableSwitching a working module on/off must not affect the behaviour of other modulesDuring normal operation (module working) protection draws no power


January 2009

Can we use just one transistor for the task of shorting and SR?

Can we accept the risk of wire-bonds carrying power from bus-cable to hybrid or should protection be placed directly on the bus-cable?

Can SR and protection be included in a single ASIC package?

Examples

6


January 2009

OR

Less material, but possibility of common mode failure

OR

Easier to implement, but depends on good wire bonding

a) Circuit option

7

No active protectionThis option has been sufficient for demonstration staves. This is a serious option for the ATLAS upgrade.

+ simpleminimum mass, minimum linesengineered redundancy including thick wire bonds & several shunt transistors

- Cannot switch modules off


January 2009

b) Circuit option

8

BonnEach module has a single line to an off-detector controller. This can be used to switch the module off (short it) or to monitor the module voltage.

+ simple+ control & monitor

default state = OC

- no fast auto-response- many bus-cable wires


January 2009

OC = Open Circuit (ie switch is “off”, module powered)

Ref ATLAS Tracker Upgrade Workshop, NIKHEF 3-7 Nov 2008Powering, Wed 5 Nov 2008, 17:30 Laura Gonellahttp://indico.cern.ch/conferenceTimeTable.py?confId=32084

c) Circuit option

9

BNLA common data line fed to a one-wire controller output is latched and used on each module to switch the module off (short it).

+ latching control+ single DCS wire+ fast auto-response

default state = OC

- no monitor- low residual module- off voltage required

to hold latch


January 2009

Ref ATLAS Tracker Upgrade Workshop, NIKHEF 3-7 Nov 2008Electronics Working Group, Tue 4 Nov 2008, 15:40 David Lynnhttp://indico.cern.ch/conferenceTimeTable.py?confId=32084


http://indico.cern.ch/conferenceTimeTable.py?confId=32084



d) Circuit options

10

VillaniSimilar to the Bonn design, but power is delivered to the one-wire controller and latch by the data line.

+ latching control+ “single” DCS wire+ no trickle power

default state = OC

- no monitor- no auto-response


January 2009


e) Circuit options

11

ExtendedAs Villani design, but latch may also be set in the safe state using the shunt regulator alarm. Also consider depletion mode FET for fail-safe.

+ latching control+ single DCS wire+ no trickle power+ auto-response

default = SC

- no monitor


January 2009

SC = Short Circuit (ie switch is “on”, module un-powered)

Comparison

12


January 2009

Proposal

Auto over-voltage protection

Auto over-current protection

Latching

Minim

um (‘off’) voltage

Circuit com

plexity

Extra bus-cable lines

Extra passive m

odule com

ponents

Extra active m

odule components

Extra m

odule mass

Extra area m

m2

Dem

onstrated

No protection N N N n/a L 0 0 0 0 0 Y

Bonn N N N 0 L n 2 1 ? ? ?

BNL Y N Y ? M 2 4 3 ? 100 Y

Villani N N Y 0 H 2 ? ? ? ? ½

Extended Y Y Y 0 H 2 ? ? ? ? N

Summary

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…circuit options are beingimplemented and evaluated…


January 2009

End

14

…circuit designs follow…


January 2009

Bonn protection

15


January 2009

Copied from presentation by Laura GonellaATLAS Tracker Upgrade Workshop, NIKHEF 3-7 Nov 2008Powering, Wed 5 Nov 2008, 17:30http://indico.cern.ch/conferenceTimeTable.py?confId=32084

BNL protection

16


January 2009

Copied from presentation by David Lynn

ATLAS Tracker Upgrade Workshop, NIKHEF 3-7 Nov 2008Electronics Working Group, Tue 4 Nov 2008http://indico.cern.ch/conferenceTimeTable.py?confId=32084

SI 1450DH1k

5k

8 nF

EDZTE613.6

ZXTDA1M832PNP-NPN Single Package

Ds2413

IN

O UT

M odule

Protection

V

I/O

G nd

P

Villani protection

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January 2009

From Giulio Villani, RAL – personal communication

Serial Powering - Protection Purpose Protect the stave Assure supply of power to a serial powered...

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