CompactPCI and AdvancedTCA Systems - OpenSystems Media

S P E C I A L
C O O L I N G
A+
B+
UVLO &
Inrush
Controller
Current
Limit
Variable
Regulator
approaches. However, the control section
is different. While a much less complex
control and interface section is required
for the managed FRU, the system must
have specialized hardware to interface
to the fan tray. Some data would need to
be reported as not available or gathered
outside the tray, for example, by using a
temperature sensor.
A second managed FRU approach would
be to use a single private I2C bus, as
shown in Figure 3, which could give
nearly all the features of the IPMB implementation
of Figure 1 with less fan
controller hardware and software, but
added system hardware and software. This
system could even store the inventory and
capabilities data in its own EEPROM, but
another controller would need to access
the information because it would not be
available on the IPMB.
A-
B-
Isolated
Supply
Intelligent FRU
Private I2C Bus
Standard interface software
2
UVLO &
Control
Uses existing shelf manager resources
EEPROM
Figure 3
Temp
Sensor
Control Logic
Requirement Summary
Fan tray requires IPMB hardware and software
Table 1
Managed FRU
Tach
Signals
Optic
Barrier
Custom interface hardware and software
Requires system to manage fan tray
As with any engineering challenge,
designing the cooling interface of an
AdvancedTCA chassis is about weighing
one advantage against another to give the
best system performance. There are performance
and cost advantages for both
approaches described earlier. While in
one system it may not be feasible to add
a separate communications bus to the fan
controller, another system may have an
unutilized private bus and overhead available
to manage the fan tray. Table 1 summarizes
Intelligent FRU and Managed
FRU requirements.
Nathan Lavoie has a BSEE from the
University of Vermont and is the vice
president of engineering of Control
Resources, Inc. a manufacturer of
off-the-shelf and custom fan trays, fan
controls, and alarms.
For more information, contact
Nathan at:
RSC# 16 @www.compactpci-systems.com/rsc
Control Resources, Inc.
11 Beaver Brook Road
Littleton, MA 01460
Tel: 978-486-4160
Fax: 978-486-4772
E-mail: nlavoie@controlres.com
Website: www.controlres.com
16 / CompactPCI and AdvancedTCA Systems / September 2005