Single Event Upset Energy Dependence
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2 nd Measurement – Feb., 2011 Test board with individual components 188 MeV protons PowerPoint PPT Presentation


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Single Event Upset Energy Dependence In a Buck-Converter Power Supply Design. LC Filter. LC Buck. LC Filter. + 200V -. + Vout -. FET Driver. Transformer. R SHUNT. R SHUNT. + V PRI -. + V SEC -. GND PRI. GND SEC. SEC Power. PRI Power. I IN*. V IN*. OpAmp. V FB. Run.

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2 nd Measurement – Feb., 2011 Test board with individual components 188 MeV protons

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2 nd measurement feb 2011 test board with individual components 188 mev protons

Single Event Upset Energy Dependence

In a Buck-Converter Power Supply Design

LC Filter

LC Buck

LC Filter

+

200V

-

+

Vout

-

FET

Driver

Transformer

RSHUNT

RSHUNT

+

VPRI

-

+

VSEC

-

GNDPRI

GNDSEC

SEC

Power

PRI

Power

IIN*

VIN*

OpAmp

VFB

Run

LT1681

Controller

Chip

Startup

&

Shutdown

Control

OVP,

OCP,

Temp, &

Monitor

Stop

Opto

Isolator

Over Temp

Startup

VOUT*

To

ELMB

(Control

Interface)

Shutdown

IOUT*

IFB

Opto

Isolator

Monitor

Voltages

Primary

Isolated Secondary

Gary Drake, Member IEEE,

James Proudfoot

Argonne National Laboratory, Lemont, IL USA

Bruce Mellado2, AnushaGopalakrishnan1,

SanishMahadik1, Robert Reed2, AbhiramiSenthilkumaran1

1 - University of Wisconsin-Madison, Madison, WI USA

2 – The University of the Witwatersrand, Johannesburg, SA

On Behalf of the ATLAS Tile Calorimeter System

The TileCAL Low Voltage System

LVPS Brick

  • Power for TileCAL Front-End Electronics

  • Novel Switching DC-DC Power Supply

    • Custom, Compact, High-Efficiency, 250 Watt

    • 8 Different Voltages  Customized Bricks

    • Water Cooled; System Interface & Monitoring

    • Environment: Magnetic Field, Radiation Tolerant

  • 256 boxes on detector, 2048 bricks, + spares

  • Reliability is Important  Infrequent Access

LVPS Box

8 bricks per Box

LVPS

Access

on

Detector

Detector Section

End of Long Barrel

Drawer Electronics

We have performed a study of the susceptibility to Single Event Upsets (SEU) on the new upgraded supplies

Radiation Testing Methodology

Block Diagram of Brick

  • Radiation Tolerance Requirements

    • 10 Years of Running, L = 1034 cm-2 sec-1

Test Setup at MGH

  • SEU Testing Program

    • Proton beam at Mass. Gen. Hospital

    • 20 – 200 MeV protons

    • Read out continuously during irradiation

Test Setup Configuration

Measurements & Results

  • The Fix

    • Soft Start not used in brick operation

    • But, circuit does control startup rate

    • Want capacitor for cold start

    • Want capacitor out of circuit for normal operation

    • Add a diode & resistor:

  • 4th Measurement – Apr., 2012 Study SEUs as a function of energy

    • 60 MeV, 80 MeV, 100.5 MeV, 140 MeV, & 216 MeV

    • Results: See energy dependence

  • 1st Measurement – Dec., 2010

    • Bricks tripped from SEU

    • 188 MeV protons

  • SEU Problem

  • 2nd Measurement – Feb., 2011

    • Test board with individual components

    • 188 MeV protons

    • Discovered: LT1681 Controller Chip trips & restarts

  • Soft Start Feature

Schematic

Soft-start capacitor

External component

Value controls startup delay

  • Theory: Bendel Parameters [1]

    • In general, SEU susceptibility depends on fab tech., feature size, layout, and configuration

    • Bendel Parameters: Parameterization of form:

    • Our fit:

LT1681 Block Diagram

  • Diode conducts at cold start

  • Diode is back biased

  • SEUs still happen, but recovery is fast

SEMI-EMPIRICAL 2 PARAMETER FIT

  • 3rd Measurement – Apr., 2011

    • Fix installed on 3 bricks

    • No more trips!

  • A Puzzle

    • SEUs not seen in earlier tests at 60 MeV

    • Why?...

[1] W.J.Stapor, et al., IEEE Trans Nucl.

Sci., Vol. 37, NO.6, pp. 1966-1973,

December 1990.


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