Operation environment issues: high radiation + high magnetic field

wideeyedarmenianElectronics - Devices

Nov 24, 2013 (3 years and 10 months ago)

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Air coil with plastic protection

Ferrite coil

23 mm

25 mm

LT3418 Ferrite Coil

LT3415 Air Coil

Output 6 amps

Input Ripple

Output Ripple

Output 6 amps

Input Ripple

Output Ripple

Output 24 amps

Input Ripple

Output Ripple

Vicor BCMB048F040T20


DC
-
DC Converters for Delivery of Low Voltage and High Currents
for the SLHC / ILC Detector Electronics in Magnetic field (2

6
Tesla)

and Radiation environments.


At Yale we constructed Low
Voltage Regulator Cards for
delivering 50K amps to the CMS
ECAL system. Starting with 48V,
6.3V unregulated is transported
30m providing 4.3V at the input to
the cards and the output is 2.5V
regulated. Using these CMOS
regulators the efficiency is only
40%

efficient.

Future projects will need 50K to
300K amps at low voltage.

95%

efficiency possible with DC
-
DC
switching converters going directly
from 48V to 1


2.5V:

x24 reduction in current

Less copper needed in detector

Less multiple scattering

Improved hermiticity

Operation environment issues: high radiation + high magnetic field

Most DC
-
DC switching converters use a ferrite core which is not suitable for use in high
magnetic fields. Our work focuses on the use of air core coils to replace the ferrite coils.

As a proof of principle, we are designing a DC
-
DC system for
an LHC or ILC silicon tracker

Several controller chips (Texas Instruments 5430, Micrel MIC2485, Linear
Technology Corporation LTC3415, and Vicor) with switching frequencies
ranging from 0.5 MHz to 8Mhz were tested by replacing the ferrite core coil
with an air core coil of similar inductance and switching a load.

Photograph of Micrel chip with ferrite coil on
the left and the air coil on the right.

Comparison of
the LT3415
DC
-
DC
converter chip
with

the ferrite coil
versus the air
coil


Our results (shown below) indicate that for high switching frequencies there
is no difference between the ferrite and air coils if the inductance is similar.

The Vicor match box size module is a good
candidate for delivering 2 Volts at up to 100
amps. It is a multi chip hybrid with ferrite
based transformers. The ASIC in it now can
withstand 20 krads. It is feasible to design
air core transformers if the operating
frequency is increased by a factor of 10 to
15 MHz. Needless to say, there are many
challenging problems to overcome

Results for the
Vicor multi
chip hybrid
with ferrite
based
transformers.


Stave with 6
sensors and the
hybrid card for an
LHC or ILC
silicon tracker.

We thank the following companies for
supplying us their evaluations boards and
samples at no charge, Vicor Corporation,
Micrel Inc and Linear Technology
Corporation.


References:

Intel 1: Peter Hazucha et al: pages 838
-
845 IEEE Journal of Solid State
Circuits, Vol. 40. NO. 4. April 2005.

Intel 2: Gerhard Schrom et al: pages 4702
-
4707 2004 35th Annual IEEE
Power Electronics Specialists Conference.

Intel 3: Gerhard Schrom et al: pages 263
-
268 Proceedings of the 2004
International Symposium on Low Power Electronics and Design (ISLPED
’04)

Nikhef: Sander Mos [sander.mos@nikhef.nl] Zero Iron Power Supply
http://www.nikhef.nl/~sanderm/zips/index.html


Mohan: Power Electronics 3rd edition authors Mohan,Underland, Robbins.
John Wiley & Sons Inc. ISBN 0
-
471
-
22693
-
9

Sokal Private Communication Nathan O. Sokal, Design Automation Inc, 4
Tyler Road, Lexington, MA, 02420, USA

Vicor: Vicor Corporation, Andover,MA, USA.

research by: S. Dhawan, D. Lynn, H. Neal, R. Sumner, M. Weber and R. Weber