U.S. patent application number 12/178060 was filed with the patent office on 2010-01-28 for techniques utilizing thermal, emi and fips friendly electronic modules.
This patent application is currently assigned to CISCO TECHNOLOGY, INC.. Invention is credited to John Borg, Wingo Cheong, Susheela N. Narasimhan, Nguyen Nguyen, Branimir Tasic, Hang Tran.
Application Number | 20100020486 12/178060 |
Document ID | / |
Family ID | 41460366 |
Filed Date | 2010-01-28 |
United States Patent
Application |
20100020486 |
Kind Code |
A1 |
Narasimhan; Susheela N. ; et
al. |
January 28, 2010 |
TECHNIQUES UTILIZING THERMAL, EMI AND FIPS FRIENDLY ELECTRONIC
MODULES
Abstract
An electronic system includes a chassis defining a substantially
plane-shaped cavity. The chassis is arranged to contain an air
stream (e.g., provided by a cooling subsystem) which flows from an
air intake side of the chassis to an air exhaust side of the
chassis through the substantially plane-shaped cavity. The air
intake side of the chassis is opposite the air exhaust side of the
chassis. The electronic system further includes a jacket circuit
board disposed within the plane-shaped cavity, and a set of
pluggable electronic modules. The jacket circuit board is oriented
within the plane-shaped cavity to receive cooling from the air
stream. Each pluggable electronic module is arranged to (i)
electronically connect to the jacket circuit board through a front
of the chassis and (ii) define a supplemental ventilation port
through which air passes to augment the air stream.
Inventors: |
Narasimhan; Susheela N.;
(Milpitas, CA) ; Tran; Hang; (San Jose, CA)
; Tasic; Branimir; (Menlo Park, CA) ; Borg;
John; (Boxborough, MA) ; Cheong; Wingo; (San
Jose, CA) ; Nguyen; Nguyen; (San Jose, CA) |
Correspondence
Address: |
BAINWOOD HUANG & ASSOCIATES LLC
2 CONNECTOR ROAD
WESTBOROUGH
MA
01581
US
|
Assignee: |
CISCO TECHNOLOGY, INC.
San Jose
CA
|
Family ID: |
41460366 |
Appl. No.: |
12/178060 |
Filed: |
July 23, 2008 |
Current U.S.
Class: |
361/679.49 ;
361/690 |
Current CPC
Class: |
H05K 7/20727
20130101 |
Class at
Publication: |
361/679.49 ;
361/690 |
International
Class: |
H05K 7/20 20060101
H05K007/20 |
Claims
1. An electronic system, comprising: a chassis which defines a
substantially plane-shaped cavity, the chassis being arranged to
contain an air stream which flows from an air intake side of the
chassis to an air exhaust side of the chassis through the
substantially plane-shaped cavity, the air intake side of the
chassis being opposite the air exhaust side of the chassis; a
jacket circuit board disposed within the plane-shaped cavity, the
jacket circuit board being oriented within the plane-shaped cavity
to receive cooling from the air stream; and a set of pluggable
electronic modules, each pluggable electronic module being arranged
to (i) electronically connect to the jacket circuit board through a
front of the chassis and (ii) define a supplemental ventilation
port through which air passes to augment the air stream.
2. An electronic system as in claim 1 wherein each pluggable
electronic module includes: a set of electronic circuit boards
which is arranged to receive cooling from the air stream when the
pluggable electronic module electronically connects with the jacket
circuit board through the front of the chassis; a perforated face
plate coupled to the set of electronic circuit boards, the
perforated face plate being arranged to provide electromagnetic
interference shielding while concurrently allowing air to
substantially pass therethough; and a bezel coupled to the
perforated face plate, the perforated face plate being arranged to
provide visual shielding while concurrently allowing air to
substantially pass therethough.
3. An electronic system as in claim 2 wherein the set of pluggable
electronic modules includes: an upstream pluggable electronic
module proximate to the air intake side of the chassis and distal
to the air exhaust side of the chassis; and a downstream pluggable
electronic module proximate to the air exhaust side of the chassis
and distal to the air intake side of the chassis, the upstream and
downstream pluggable electronic modules abutting each other when
each electronically connects with the jacket circuit board through
the front of the chassis.
4. An electronic system as in claim 3 wherein the substantially
plane-shaped cavity defined by the chassis extends in a
substantially horizontal plane to guide the air stream in a lateral
direction; wherein the jacket circuit board extends in the
substantially horizontal plane to receiving cooling from the air
stream; wherein each of the upstream pluggable electronic module
and the downstream pluggable electronic module includes (i) a
motherboard which is disposed horizontally when electronically
connecting to the jacket circuit board, (ii) a daughter card which
is disposed horizontally when electronically connecting to the
jacket circuit board, and (iii) a metallic tray which is disposed
horizontally when electronically connecting to the jacket circuit
board, the motherboard being disposed between the metallic tray and
the daughter card in a parallel manner to enable laminar air stream
flow through each of the upstream pluggable electronic module and
the downstream pluggable electronic module.
5. An electronic system as in claim 2 wherein, for each pluggable
electronic module: the perforated face plate of that module is
elongated and defines a perforated face plate section having an
array of perforations and a non-perforated face plate section
having a substantially uniform surface, and the bezel of that
module is elongated to overlay the perforated face plate of that
module and defines (i) a perforated bezel section having an array
of perforations, the perforated bezel section overlaying the
non-perforated face plate section of the perforated face plate, and
(ii) a non-perforated bezel section having a substantially uniform
surface, the non-perforated bezel section overlaying the perforated
face plate section of the perforated face plate.
6. An electronic system as in claim 5 wherein, for each pluggable
electronic module, the set of electronic circuit boards of that
module has a processing circuit disposed in a location which is
adjacent the perforated face plate section of the perforated face
plate of that module to dissipate heat from the processing circuit
into air passing through that perforated face plate section as that
air augments the air stream.
7. An electronic system as in claim 2 wherein, for each pluggable
electronic module, (i) the perforated face plate of that module is
substantially flat, and (ii) the bezel of that module is
curved.
8. An electronic system as in claim 7 wherein, for each pluggable
electronic module, the bezel of that module defines (i) a front
having the perforated bezel section and the non-perforated bezel
section of the bezel of that module, (ii) a top section, and (iii)
a bottom section which is opposite the top section, the top and
bottom sections defining perforations.
9. An electronic system as in claim 2 wherein, for each pluggable
electronic module, (i) the perforated face plate of that module
includes metallic material, and (ii) the bezel of that module
includes a polymer material to inhibit heat conduction from the
perforated face plate to the bezel.
10. An electronic system as in claim 2 wherein, for each pluggable
electronic module, the bezel of that module includes metallic
material to provide electromagnetic interference shielding.
11. An electronic system as in claim 2 wherein each pluggable
electronic module further comprises a set of screws which thread
from the perforated face plate of that module into the bezel of
that module to prevent detachment of the bezel from the perforated
face plate while that module electronically connects with the
jacket circuit board through the front of the chassis.
12. A pluggable electronic module to electronically connect to a
jacket circuit board through a front of a chassis, the pluggable
electronic module comprising: a set of electronic circuit boards
which is arranged to receive cooling from an air stream in the
chassis when the pluggable electronic module electronically
connects with a jacket circuit board through the front of the
chassis, the air stream flowing from an air intake side of the
chassis to an air exhaust side of the chassis which is opposite the
air intake side of the chassis; a perforated face plate coupled to
the set of electronic circuit boards, the perforated face plate
being arranged to provide electromagnetic interference shielding;
and a bezel coupled to the perforated face plate, the perforated
face plate being arranged to provide visual shielding, the
perforated face plate and the bezel forming a supplemental
ventilation port which allows air to substantially pass therethough
to augment the air stream in the chassis.
13. A pluggable electronic module as in claim 12 wherein the set of
electronic circuit boards includes a motherboard, a daughter card,
and a metallic tray which are disposed substantially parallel to
each other to enable laminar air stream flow through the module,
the motherboard residing between the metallic tray and the daughter
card.
14. A pluggable electronic module as in claim 13 wherein the
perforated face plate of is elongated and defines a perforated face
plate section having an array of perforations and a non-perforated
face plate section having a substantially uniform surface; and
wherein the bezel is elongated to overlay the perforated face plate
and defines (i) a perforated bezel section having an array of
perforations, the perforated bezel section overlaying the
non-perforated face plate section of the perforated face plate, and
(ii) a non-perforated bezel section having a substantially uniform
surface, the non-perforated bezel section overlaying the perforated
face plate section of the perforated face plate.
15. A pluggable electronic module as in claim 14 wherein the set of
electronic circuit boards includes a processing circuit disposed in
a location which is adjacent the perforated face plate section of
the perforated face plate to dissipate heat from the processing
circuit into air passing through that perforated face plate section
as that air augments the air stream in the chassis.
16. A pluggable electronic module as in claim 12 wherein the
perforated face plate of that module is substantially flat, and the
bezel of that module is curved.
17. A pluggable electronic module as in claim 16 wherein the bezel
defines (i) a front having the perforated bezel section and the
non-perforated bezel section of the bezel, (ii) a top section, and
(iii) a bottom section which is opposite the top section, the top
and bottom sections defining perforations.
18. A pluggable electronic module as in claim 12 wherein the
perforated face plate includes metallic material, and the bezel
includes a polymer material to inhibit heat conduction from the
perforated face plate to the bezel.
19. A pluggable electronic module as in claim 12 wherein the bezel
includes metallic material to provide electromagnetic interference
shielding.
20. A pluggable electronic module as in claim 12, further
comprising: a set of screws which thread from the perforated face
plate into the bezel of that module to prevent detachment of the
bezel from the perforated face plate while the module
electronically connects with the jacket circuit board through the
front of the chassis.
Description
BACKGROUND
[0001] A variety of constraints may exist on a particular
electronic device. For example, the circuitry of the electronic
device may be required to operate within a certain temperature
range or otherwise risk the possibility of improper operation or
damage. As another example, the electronic device may need to
comply with certain electromagnetic interference (EMI)
requirements.
[0002] More recently, attention has been paid to developing and
imposing various security standards. Examples of such standards
include the Federal Information Processing Standards (FIPS) which
relate to cryptographic modules used in security systems which
protect unclassified information within information technology (IT)
systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The foregoing and other objects, features and advantages
will be apparent from the following description of particular
embodiments of the invention, as illustrated in the accompanying
drawings in which like reference characters refer to the same parts
throughout the different views. The drawings are not necessarily to
scale, emphasis instead being placed upon illustrating the
principles of various embodiments of the invention.
[0004] FIG. 1 is a general perspective view of an electronic system
which utilizes a set of thermal, EMI and FIPS friendly electronic
modules.
[0005] FIG. 2 is a cross-sectional top view of the electronic
system of FIG. 1 showing air flow patterns through the electronic
system.
[0006] FIG. 3 is a general top view of particular modularized
components of the electronic system of FIG. 1.
[0007] FIG. 4 is a detailed perspective view a main assembly of the
electronic system of FIG. 1.
[0008] FIG. 5 is a detailed perspective view a main assembly of
FIG. 4 with one of multiple pluggable electronic modules removed
from the main assembly.
[0009] FIG. 6 is an exploded perspective view of portions of a
pluggable electronic module.
[0010] FIG. 7 is a detailed perspective view of a bezel of the
pluggable electronic module.
[0011] FIG. 8 is a general top view of the pluggable electronic
module.
[0012] FIG. 9 is a view of the pluggable electronic module showing
controlled air flow through the bezel and a perforated face plate
in combination with a portion of an existing air stream.
DETAILED DESCRIPTION
Overview
[0013] Unfortunately, it is difficult to concurrently comply with
multiple electronic constraints on an electronic device when
certain characteristics of the device compete against each other.
For example, for an existing electronic device, the current cooling
resources may be sufficient to maintain the proper operating
temperature of electronic circuitry within the device. However,
such cooling resources may be inadequate to accommodate any upgrade
to faster, higher power, components and thus hotter electronic
circuitry without some other modification to the cooling subsystem
of the device (e.g., a costly upgrade of the fans and the fans'
power sources).
[0014] Moreover, if additional cooling ducts were simply added to
the device's housing, such cooling ducts could move the device out
of compliance with various other requirements such as EMI and FIPS
requirements. In particular, if existing cooling ducts are made
larger, such ducts could become a source of EMI leakage and/or a
security threat.
[0015] Advantageously, an improved electronic system utilizes a set
of thermal, EMI and FIPS friendly electronic modules which are
capable of maintaining EMI and FIPS protection as well as providing
supplemental ventilation though which air passes to augment an air
stream within the system. Such a system enjoys robust and reliable
compliance with thermal, EMI and FIPS requirements during
operation.
[0016] One embodiment is directed to an electronic system which
includes a chassis defining a substantially plane-shaped cavity.
The chassis is arranged to contain an air stream (e.g., provided by
a cooling subsystem formed by fan and filter assemblies) which
flows from an air intake side of the chassis to an air exhaust side
of the chassis through the substantially plane-shaped cavity. The
air intake side of the chassis is opposite the air exhaust side of
the chassis. The electronic system further includes a jacket
circuit board disposed within the plane-shaped cavity, and a set of
pluggable electronic modules. The jacket circuit board is oriented
within the plane-shaped cavity to receive cooling from the air
stream. Each pluggable electronic module is arranged to (i)
electronically connect to the jacket circuit board through a front
of the chassis and (ii) define a supplemental ventilation port
through which air passes to augment the air stream.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0017] FIG. 1 is a perspective view of an electronic system 20
which is constructed and arranged to perform a set of electronic
operations. Such operations may include general purpose operations
(e.g., general communications, general computations, read and write
operations, etc.), specialized operations (e.g., complex
calculations, measurement sensing/sampling, complex data
processing, graphical display, etc.), and/or combinations thereof.
By way of example, the electronic system 20 is described below as a
high-speed network switch or a similar data communications device
which is adapted to guide data elements such as TCP/IP packets
within a computerized network.
[0018] As shown in FIG. 1, the electronic system 20 includes a
chassis (or frame) 22, a fan assembly 24, a filter assembly 26, an
interconnect 28, and a set of blade-style main electronic
assemblies 30(1), 30(2), 30(3), . . . (collectively, main
assemblies 30). The fan assembly 24 is arranged to draw air into
and through the chassis 22 in order to remove heat from operating
circuitry of the main electronic assemblies 30. The filter assembly
26 allows ambient air to flow into the chassis 22, as well as
provides visual and electromagnetic interference (EMI) shielding
(for illustration purposes, a portion of the filter assembly 26 is
omitted in FIG. 1). The interconnect 28 (e.g., a backplane or
midplane, a set of cable harnesses, etc.) is arranged to facilitate
both power signal and data signal exchange with the main electronic
assemblies 30 and/or to external devices.
[0019] As further shown in FIG. 1, the chassis 22 defines multiple
plane-shaped cavities 32(1), 32(2), 32(3), . . . (collectively,
cavities 32) to hold respective main electronic assemblies 30. In
particular, with respect to each cavity 32, the chassis 22 is
constructed and arranged to contain an air stream 34 which flows
from an air intake side 36(I) of the chassis 22 to an air exhaust
side 36(E) of the chassis 22 through that cavity 24. By way of
example only, the cavities 32 are shown as stacking in the
Z-direction, with each cavity 32 extending in the X-Y plane for
side-to-side (e.g., right-to-left) flow of the air stream 34
substantially in the negative X-direction in FIG. 1.
[0020] Such an arrangement provides an efficient high density
configuration for the operating electronic circuitry of the
electronic system 20. Moreover, this arrangement enables a user
(e.g., a technician) to conveniently access the main electronic
assemblies 30 at a front 38 of the chassis 22. To this end, it
should be understood that each main electronic assembly 30 includes
a jacket circuit board 40 and multiple pluggable electronic modules
42. For illustration purposes, one of the pluggable electronic
modules 42 is omitted at location 44 in FIG. 1. As will be
described in further detail shortly, each pluggable electronic
module 42 is thermal, EMI and FIPS friendly. Further details will
now be provided with reference to FIG. 2.
[0021] FIG. 2 is a cross-sectional top view of the electronic
system 20 showing general air flow patterns through a particular
cavity 32 defined by the chassis 22. As shown, the fan assembly 24
includes multiple fans 50 to generate the air stream 34 through the
cavity 32. Although the fans 50 are shown exhausting air from the
cavity 32, alternatively the fans 50 may push air into and through
the cavity 32.
[0022] As further shown in FIG. 2, the main electronic assembly 32
includes a jacket circuit board 40, an upstream pluggable
electronic module 42(U) and a downstream pluggable electronic
module 42(D) (collectively, modules 42). The modules 42 abut each
other in a side-by-side high-density manner when electronically
connecting with the jacket circuit board 40 through the front 38 of
the chassis 22.
[0023] When fully installed as shown in FIG. 2, the jacket circuit
board 40 connects to the interconnect 28, and the modules 42
connect to the jacket circuit board 40 (also see FIG. 1). In
particular, the upstream pluggable electronic module 42(U) resides
proximate to the air intake side 36(I) of the chassis 22 and distal
from the air exhaust side 36(E) of the chassis 22. In contrast, the
downstream pluggable electronic module 42(D) resides proximate to
the air exhaust side 36(E) and distal from the air intake side
36(I). In some arrangements, the modules 42 have the same
configuration and/or are interchangeable, thus being primarily
distinguishable by only their position (and perhaps software
signaling) within the electronic system 20.
[0024] The jacket circuit board 40 is arranged for installation
into the cavity 32 and removal from the cavity 32 through the front
38 of the chassis 22 (FIG. 1). When the jacket circuit board 40
resides within the cavity 32, the jacket circuit board lays
relatively flat in the X-Y plane to enable the air stream 34 to
flow in a laminar manner therethrough.
[0025] Similarly, the pluggable electronic modules 42 are arranged
for installation into the cavity 32 and for removal from the cavity
32 through the front 38 of the chassis 22. When the pluggable
electronic modules 42 reside side-by-side within the cavity 32, the
pluggable electronic modules 42 lay relatively flat in the X-Y
plane to enable circuitry of the modules 42 to enjoy and maintain
the laminar flow of the air stream 34.
[0026] At this point, it should be understood that the pluggable
electronic modules 42 may include thermally sensitive circuitry at
particular locations, e.g., illustrated by the dashed circles
52(U), 52(D) (collectively, circuitry 52) in FIG. 2. For such
circuitry 52, the air flow from the intake side 36(I) to the
exhaust side 36 through the cavity 32 may be insufficient alone to
provide proper cooling. Fortunately, the pluggable electronic
modules 42 are arranged with supplemental ventilation ports 54
(i.e., port 54(U) for module 42(U) and port 54(D) for module 42(D))
through which air passes to augment the air stream 34. Such
augmentation enhances heat removal from the thermally sensitive
circuitry 52 at the particular locations thus enabling that
circuitry 52 to remain within a proper and prescribed temperature
range for correct operation.
[0027] It should be clear in FIG. 2 that the upstream pluggable
electronic module 42(U) receives substantially fresh air through
the filter 26 and the supplemental ventilation port 54(U). As a
result, the circuitry 52(U) receives adequate cooling.
[0028] Additionally, the downstream pluggable electronic module
42(D) receives partially heated air that has passed by the upstream
pluggable electronic module 42(U) and substantially fresh air
through the supplemental ventilation port 54(D). This augmented
flow of air through the downstream pluggable electronic module
42(D) provides adequate cooling as well so that the circuitry 52(D)
remains within the normal operating temperature range. Further
details will now be provided with reference to FIGS. 3 through
5.
[0029] FIG. 3 is a general top view showing certain modularization
features of the electronic system 20. FIG. 4 is a detailed
perspective view a main assembly of the electronic system 20. FIG.
5 is a detailed perspective view the main assembly when one of the
pluggable electronic modules 42 (e.g., the upstream pluggable
electronic module 42(U)) is removed.
[0030] As shown in FIGS. 3 through 5, the main assembly 32 (i.e.,
the jacket circuit board 40 and modules 42) is arranged to insert
into a cavity 32 of the chassis 22 and de-insert from the cavity 32
of the chassis 22 as illustrated by the arrow 60 along the Y-axis
(FIG. 3). A set of levers 62 (FIG. 4) facilitate installation and
removal of the main assembly 32 with respect to the chassis 20
(e.g., to evenly apply proper insertion/extraction forces). It
should be understood that connection is made between the jacket
circuit board 40 of the main assembly 32 and the interconnect 28 in
a blind mating manner.
[0031] Similarly, each module 42 is arranged to install within and
de-install from the jacket circuit board 40 as illustrated by the
arrow 64 along the Y-axis (FIG. 3). A set of levers 66 (FIG. 5)
facilitate installation and removal of each module 42 with respect
to the jacket circuit board 40 (e.g., to evenly apply proper
insertion/extraction forces). It should be understood that
connection is also made between each module 42 and the jacket
circuit board 40 in a blind mating manner.
[0032] By way of example, the jacket circuit board 40 operates as a
network switch security module, and each module 42 operates as a
shared port adapter (SPA) module thus forming a high performance
device for firewall and virtual private network (VPN) services. In
some arrangements, the main assembly 32 is hot-swappable with
respect to the interconnect 28, and/or the modules 42 are
hot-swappable with respect to the jacket circuit board 40. Further
details of a module 42 will now be provided with reference to FIGS.
6 through 8.
[0033] FIG. 6 shows particular portions of a pluggable electronic
module 42. FIG. 7 is a bezel of the pluggable electronic module 42.
FIG. 8 is a general top view of the pluggable electronic module 42
in assembled form. To better illustrate certain details of the
pluggable electronic module 42, FIGS. 6 and 7 show the parts of the
pluggable electronic module 42 at an inverted angle. Along these
lines, it should be understood that the X, Y and Z axes shown in
FIGS. 6 through 8 are intended to correspond to the same X, Y and Z
axes in the other figures.
[0034] The pluggable electronic module 42 includes a support
assembly 70 (FIG. 6), a set of electronic circuit boards 72(M),
72(D) (collectively, circuit boards 72) (FIG. 7), and a bezel 74
(FIG. 8). The support assembly 70 includes a metallic tray 76 and a
perforated metallic face plate 78 (FIG. 6). When the various parts
of the module 42 are assembled, the metallic tray 76, and each of
the electronic circuit boards 72 stack in a substantially parallel
manner, i.e., each extending horizontally along the X-Y plane, to
match the orientation of the jacket circuit board 40 which also
extends horizontally along the X-Y plane (also see FIG. 1).
Accordingly, the various parts of the module 42 receive cooling
from the air stream 34 as it flows laterally through the chassis
22.
[0035] The metallic tray 76 is arranged to rigidly engage the
chassis 22 and support the circuit boards 72. Additionally, the
metallic tray 76 provides a degree of EMI shielding between the
cavities 32 in the Z-direction (also see FIG. 1).
[0036] Similarly, the perforated metallic face plate 78 (FIG. 6) is
arranged to support the bezel 74 and the levers 66 (also see FIG.
5), as well as rigidly connect to the metallic tray 76 thus
extending the EMI shielding to the front of the module 72 and
enabling a user to maneuver the module 42 (e.g., install the module
into the chassis 22 and remove the module 42 from the chassis 22)
by operating the levers 66. In some arrangements, the metallic tray
76 and the perforated metallic face plate 78 are formed from a
common section of sheet metal stock thus forming a sturdy and
durable integrated support member.
[0037] As shown in FIGS. 6 and 8, the perforated metallic face
plate 78 is elongated along the X-axis and defines an array of face
plate perforations 80 and a non-perforated face plate section 82
having a substantially uniform surface. The array of face plate
perforations 80 allows ambient air to pass through the perforated
metallic face plate 78 for augmented cooling of the circuit board
components of the circuit boards 72 which are immediately adjacent
the array of face plate perforations 80. Additionally, the
non-perforated face plate section 82 provides a visual barrier
(i.e., visual shielding) that prevents viewing of components of the
circuit boards 72 which are immediately behind the non-perforated
face plate section 82, e.g., see the area 84 in FIG. 8.
[0038] Similarly, as shown in FIGS. 7 and 8, the bezel 74 is
elongated along the X-axis and defines an array of bezel
perforations 86 and a non-perforated bezel section 88 having a
substantially uniform surface. The array of bezel perforations 86
allows ambient air to pass through the bezel 74 and reach the
perforated metallic face plate 78. Furthermore, the non-perforated
bezel section 88 provides a visual barrier that prevents viewing of
any objects which are immediately behind the non-perforated bezel
section 88, e.g., see the area 90 in FIG. 8.
[0039] When the bezel 74 is properly in place relative to the
perforated metallic face plate 78, the arrays of perforations are
at opposite ends (see FIG. 8). That is, the array of bezel
perforations 86 is in front of or overlays the non-perforated face
plate section 82, and the non-perforated bezel section 88 is in
front of or overlays the array of face plate perforations 80. As a
result, the combination of the bezel 74 and the perforated metallic
face plate 78 robustly and reliably conceal the circuit boards 72
from view. Accordingly, the module 72 is capable of providing
visual security against undesired viewing, e.g., FIPS
compliance.
[0040] Nevertheless, the perforations enable air at the front of
the module 42 to pass therethrough thus offering a thermal friendly
solution particularly if the circuit boards 72 include critical
circuitry 72 that may not be able to receive adequate cooling from
only air entering through the filter assembly 26. In some
arrangements, the top 92 and bottom 94 sections of the bezel 74
(opposite the top 92 on the other side of the bezel 74 across from
the sections 86, 88) define further perforations 96 which are
disposed proximate to the array of bezel perforations 86 for
additional airflow. The locations of such perforations 96 do not
provide a problematic line of sight to the components of the
circuit boards 72 thus maintaining acceptable visual security.
[0041] In some arrangements, the bezel 74 has a curved contour in
contrast to a substantially flat configuration for the face plate
78. Such arrangements, enable concurrent fulfillment of thermal,
EMI and FIPS requirements in an advantageous and aesthetic
manner.
[0042] Moreover, in some arrangements, the bezel 74 mounts to the
face plate 78 via a set of screws 98 (shown generally as arrows 98
pointing towards the bezel 74 in FIGS. 6 and 8 for simplicity)
which initially thread from the face plate 78 are which are not
accessible through the front of the bezel 74. Accordingly, the set
of screws 98 prevents a user from removing the bezel 74 while the
module 72 is in operation, i.e., the set of screws prevents
detachment of the bezel 74 from the face plate 78 while the module
72 electronically connects with the jacket circuit board 40 through
the front 38 of the chassis 22.
[0043] In some arrangements, the bezel 74 is free of metallic
material to reduce thermal conductivity for user safety. For
example, the bezel 74 is capable of being formed of a polymer
material to inhibit heat conduction from the metallic face plate 78
to the bezel 74. Accordingly, such arrangements avoid significant
heat conduction from the metallic face plate 78 to the bezel 74
which could otherwise result in a user safety concern.
[0044] In other arrangements, the bezel 74 further includes
metallic material (e.g., a metallic paint or coating) to provide
additional EMI shielding. If a means of protection for the user
exists, the bezel 74 is capable of being formed of metal for
enhanced heat dissipation. Further details will now be provided
with reference to FIG. 9 in combinations with the FIGS. 6 through
8.
[0045] FIG. 9 generally shows air flow patterns with respect to the
module 42 when the module 42 is properly installed within the
chassis 22. As shown, the module 42 enjoys cooling from both the
air stream 34 as well as from additional air flow 100 through the
front 102 of the module 42. With the resulting augmented air flow,
enhanced cooling occurs at the location 104 which generally
corresponds to the area 90 immediately in front of the array of
face plate perforations 80 and slightly downstream from that area
90 (FIG. 8). Accordingly, the location 104 is particularly
well-suited for temperature critical components that may not be
able to receive adequate cooling from the air through the filter
assembly 26 alone (also see circuitry 52 in FIG. 2).
[0046] For example, in some arrangements, the circuit board 72(M)
is configured as a motherboard having a relatively high power
processing circuit 106 disposed in the location 104 (see FIGS. 6
and 9). In such a situation, further suppose that the processing
circuit 100 includes a heat sink 108 which is adjacent the
perforated face plate section 80 of the perforated face plate 78.
Furthermore, in these arrangements, the circuit board 72(D) is a
daughter card having relatively high speed memory in support of
operation of the processing circuit 106.
[0047] In the above-described particular arrangements, the
motherboard 72(M) is tightly disposed between the metallic tray 76
and the daughter card 72(D). Even so, the additional air flow 100
passing through the front 102 of the module 72, in combination with
the air stream 34 originating from the air intake side 36(I) of the
chassis 22, is sufficient to provide adequate cooling to all of the
circuitry of the module 42. It should be understood that
experimental data has been accumulated which demonstrates that such
cooling reliably occurs regardless of whether the module 42 is
installed as the upstream pluggable electronic module 42(U) or the
downstream pluggable electronic module 42(D).
[0048] As described above, an improved electronic system 20
utilizes a set of thermal, EMI and FIPS friendly electronic modules
42 which are capable of maintaining EMI and FIPS protection as well
as providing supplemental ventilation though which air passes to
augment an air stream 34 within the system 20. Such a system 20
enjoys robust and reliable compliance with thermal, EMI and FIPS
requirements during operation.
[0049] While various embodiments of the invention have been
particularly shown and described, it will be understood by those
skilled in the art that various changes in form and details may be
made therein without departing from the spirit and scope of the
invention as defined by the appended claims.
[0050] For example, it should be understood that the electronic
system 20 was described as including two modules 42 by way of
example only. In other arrangements, each jacket circuit board 40
is capable of receiving a different number of modules 42, e.g.,
one, three, four, and so on.
[0051] Additionally, it should be understood that the orientation
for the main assemblies 30 was described above as being
lateral/horizontal by way of example. In other arrangements, the
main assemblies 30, and thus the air stream 34, are oriented
differently (e.g., bottom to top, front to back, etc.).
* * * * *