U.S. patent application number 09/198755 was filed with the patent office on 2001-08-23 for sub-modular configurable avionics.
Invention is credited to DAMEROW, MILTON F., PORTER, DONALD A., SHALER, BARTON G..
Application Number | 20010015888 09/198755 |
Document ID | / |
Family ID | 22734699 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010015888 |
Kind Code |
A1 |
SHALER, BARTON G. ; et
al. |
August 23, 2001 |
SUB-MODULAR CONFIGURABLE AVIONICS
Abstract
A line replaceable module (LRM) configured with a plurality of
mini-modules, each of which have relatively higher contact
densities than currently available LRMs with the same form factor,
for example, a Standard Electrical Module-Size E (SEM-E) form
factor. The mini-modules are significantly less expensive than an
entire module allowing such mini-modules to be disposable,
eliminating relatively costly fault diagnostics and repair. Each
mini-module includes a printed circuit board which includes a rigid
primary portion, a rigid secondary portion and flexible portion
interconnecting the primary and secondary portions. The rigid
secondary portion may be configured to provide dual-sided
interconnection to a backplane data bus. Use of the dual-sided
rigid secondary portion provides for generous spacing for contact
densities much higher than known contact densities for LRMs with
the same form factor. The rigid primary portion carries the
components forming the LRM. The use of the flexible portion
provides compensation for tolerance variations as well as
vibrational and thermal stress relative to connector systems used
on known SEM-E LRMs.
Inventors: |
SHALER, BARTON G.; (SOLANA
BEACH, CA) ; PORTER, DONALD A.; (SAN DIEGO, CA)
; DAMEROW, MILTON F.; (POWAY, CA) |
Correspondence
Address: |
PATENT COUNSEL
TRW INC
SPACE AND ELECTRONICS GROUP
ONE SPACE PARK E2/6072
REDONDO BEACH
CA
90278
|
Family ID: |
22734699 |
Appl. No.: |
09/198755 |
Filed: |
November 24, 1998 |
Current U.S.
Class: |
361/736 ;
361/729; 361/803; 439/493; 439/67 |
Current CPC
Class: |
H01R 13/658 20130101;
H05K 1/144 20130101; H05K 1/189 20130101; H01R 12/721 20130101;
H05K 3/0058 20130101; H05K 2201/2009 20130101; H05K 7/1409
20130101; H05K 3/4691 20130101; H05K 1/117 20130101 |
Class at
Publication: |
361/736 ;
361/729; 361/803; 439/67; 439/493 |
International
Class: |
H01R 012/24; H05K
001/11; H05K 001/14 |
Claims
What is claimed and desired to be secured by Letters Patent of the
United States is:
1. A line replacement module (LRM) used for carrying a plurality of
electronic components aboard an aircraft, the LRM adapted to be
interconnected to a plurality of backplane contacts forming a
serial data bus, the LRM comprising: a plurality of mini-modules,
each mini-module including a primary portion, a secondary portion
and one or more flexible interconnecting portions electrically
connected between said primary portion and said secondary portion,
said primary portion adapted to carry said plurality of electronic
components, said secondary portions configured for dual side
electrical interconnectivity with said backplane contacts and
adapted to be interconnected with a predetermined number of
backplane contacts.
2. The connector system as recited in claim 1, wherein said LRM is
formed to have a predetermined form factor.
3. The connector system as recited in claim 1, wherein said form
factor is a Standard Electronic Module-Size E (SEM-E) connector
system.
4. The connector system as recited in claim 1, wherein each of said
secondary portions is provided with a plurality of contact pads for
enabling said backplane contacts to be soldered thereto.
5. The connector system as recited in claim 1, wherein said
secondary portions are disposed adjacent one end of said primary
portions and generally parallel thereto.
6. The connector system as recited in claim 5, wherein said
secondary portions are offset from said primary portions.
7. The connector system as recited in claim 6, wherein said
flexible interconnecting portions are flexible and formed with an
offset to enable interconnection between said rigid primary
portions and said rigid secondary portions.
8. A mini-module for a line replacement module (LRM) for use on an
aircraft, the LRM comprising: a primary printed circuit board (PCB)
portion for carrying predetermined circuitry adapted to be
connected to a predetermined data bus; a secondary PCB portion
configured for dual-sided connection to a plurality of contacts
forming a data bus; and an interconnecting portion, interconnected
between said secondary PCB portion and said primary PCB
portion.
9. The LRM as recited in claim 8, wherein said primary PCB portion
is rigid.
10. The LRM as recited in claim 9, wherein said secondary PCB
portion is formed to be generally parallel to said primary PCB
portion but offset therefrom.
11. The LRM as recited in claim 10, wherein said secondary PCB
portion is rigid.
12. The LRM as recited in claim 11, wherein said interconnecting
portion is flexible.
13. The LRM as recited in claim 1, wherein said plurality is
two.
14. The LRM as recited in claim 1, wherein said plurality is four.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a line replaceable module
LRM for a digital avionics system, and more particularly to a
modular LRM configured from self-contained mini-boards, for
example, two to four mini-boards, with increased functionality
adapted to interface with the digital avionics system by way of a
high contact density backplane connector.
[0003] 2. Description of the Prior Art
[0004] Avionic control systems aboard aircraft are implemented by
way of modules that are adapted to be connected to the aircraft
data bus. Such modules are known as line replaceable modules (LRM).
For example, the Boeing B-777 Airplane Information Management
System (AIMS) utilizes a total of eleven LRMs connected to common
chassis. Due to the limited space available on aircraft, generally
only one or two chassis' are permitted per aircraft. Each chassis
may include two power LRMs, each connected to different power
buses; four I/O LRMs; three central processing modules (CPM) LRMs;
an autothrottle LRM; and a communication LRM. The various LRMs
within the chassis are used for various functions, including flight
management, electronic flight instrument systems, engine indicating
and crew alerting system display management.
[0005] Various bus architectures are known for interconnecting the
LRMs. In civil aircraft, the LRMs within each chassis are known to
be connected to what is known as an ARINC 659 backplane data bus,
which operates at about 30 MBIT/S over either a twisted wire pair
or fiberoptic cables.
[0006] Due to the limited space aboard an aircraft, the form factor
of such LRMs is specified by various standards. For example, a
MIL-STD-28787 standard describes a number of standard
configurations and sizes for electronic modules, including LRMs.
The aforementioned standard specifies a Standard Electronic
Module-Size E (SEM-E) form factor for an LRM defined as a module
5.88" high and 6.4" deep. The width of the SEM-E module can vary in
0.1" increments from about 0.28" to 0.58". The dimensional
constraints of the SEM-E LRM limits contact density to about 400 or
less. Unfortunately, with the ever increasing complexity of
avionics, higher contact densities are required.
[0007] Known LRMs include two to four printed circuit boards (PCB)
for example, up to a maximum size of 5".times.5" for carrying
various components to perform the specified function as discussed
above. Each PCB is formed with an edge connector along one edge for
electrically interfacing the PCB to a backplane data bus within the
LRM chassis. In applications where contact densities of more than
400 are required, one known approach is to provide interconnections
between the PCBs, as well as reduced spacing between contacts. As
such, known LRM's which must meet the SEM-E form factor utilize
flexible connectors and/or cross-overs to provide interfaces
between the PCBs. Due to the different contact lengths and close
spacing required in such applications, electrical performance is
known to be degraded in such applications as a result of the
impedance variability and cross-talk between contacts.
[0008] There are other problems associated with known LRMS. For
example, fault detection and fault isolation capabilities are
required down to the component level. As such, in applications
where increased contact densities are required, the fault detection
and fault isolation requirements result in relatively complex
boards increasing the cost and complicating the maintenance of such
boards. Moreover, known SEM-E modules are designed and fabricated
by single suppliers with virtually no integration capability
between suppliers. In addition, the current costs of such modules
is in the range of $15,000-$20,000. Due to such a high cost, such
modules are not disposable and are known to result in relatively
expensive fault diagnostics and repair when problems are detected.
Thus, there is a need for reduced cost modular LRM which enables
defective modules to be discarded and which enables all PCBs in the
module to interface by way of the backplane database rather than
the interboard connectors.
SUMMARY OF THE INVENTION
[0009] Briefly, the present invention relates to a line replaceable
module (LRM) configured with a plurality of mini-modules, each of
which have relatively higher contact densities than currently
available LRMs with the same form factor, for example, a Standard
Electrical Module-Size E (SEM-E) form factor. The mini-modules are
significantly less expensive than an entire module allowing such
mini-modules to be disposable, eliminating relatively costly fault
diagnostics and repair. Each mini-module includes a printed circuit
board which includes a rigid primary portion, a rigid secondary
portion and flexible portion interconnecting the primary and
secondary portions. The rigid secondary portion may be configured
to provide dual-sided interconnection to a backplane data bus. Use
of the dual-sided rigid secondary portion provides for generous
spacing for contact densities much higher than known contact
densities for LRMs with the same form factor. The rigid primary
portion carries the components forming the LRM. The use of the
flexible portion provides compensation for tolerance variations as
well as vibrational and thermal stress relative to connector
systems used on known SEM-E LRMs.
BRIEF DESCRIPTION OF THE DRAWING
[0010] These and other objects of the present invention will be
readily understood with reference to the following specification
and attached drawing, wherein:
[0011] FIG. 1 is a perspective view of an LRM in accordance with
one embodiment of the present invention shown with the chassis and
cover removed for clarity.
[0012] FIG. 2 is a sectional view of the LRM in accordance with the
present invention shown connected to backplane contacts forming an
aircraft data bus within an LRM chassis.
[0013] FIG. 3 is a sectional view of an alternate embodiment of the
LRM illustrated in FIG. 2.
[0014] FIG. 4 is an elevational view of an alternate embodiment of
the LRM in accordance with the present invention with four
mini-modules shown connected to the backplane and partially cut
away to illustrate the mini-modules.
[0015] FIG. 5 is an exploded perspective view of the LRM
illustrated in FIG. 4.
[0016] FIG. 6 is a perspective view of the LRM illustrated in FIG.
5, shown with two mini-modules disconnected.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention relates to a line replaceable module
(LRM) formed from a plurality of mini-modules for use in avionic
control systems. The LRM in accordance with the present invention
provides for relatively higher contact density and thus increased
functionality than LRMs with the same form factor without the need
for inter-board connectors. The LRM in accordance with the present
invention is adapted to be used is a Standard Electrical
Module-Size E (SEM-E) as set forth in Military Specification
MIL-STD-28787 in which, the configuration, as well as the size, of
such modules used in such avionic systems is known to be
specified.
[0018] The use of mini-modules in the LRM in accordance with the
present invention provides several advantages over known LRMs.
First, the cost of the mini-modules is significantly less than an
entire LRM, thus allowing such mini-modules to be classified as
disposable which eliminates costly fault diagnostics and repair.
Secondly, the mini-modules are provided with relatively
high-density connectors, allowing the mini-modules to be
self-contained and independent. As such, each mini-module is
connected to the backplane data bus, thus providing isolation
between mini-modules. Moreover, since the mini-modules are isolated
and communicate through the backplane, mini-modules from various
suppliers can be integrated and no other interboard connections are
required.
[0019] Both half and quarter mini-module embodiments of the
invention are disclosed. FIG. 1 illustrates an LRM configured with
two mini-modules. FIGS. 4, 5, and 6 illustrate an alternate
embodiment configured with four mini-modules. FIGS. 2 and 3
illustrate different embodiments of the mini-modules.
[0020] Referring to FIG. 1, LRM in accordance with the present
invention is generally referred to with the reference numeral 20.
However, as will be understood by those of ordinary skill in the
art, the connector system in accordance with the present invention
LRM 20 can be used for various purposes other than in connection
with LRMs. The LRM 20 includes a pair of mini-modules 19, 21; each
mini-module 19, 21 including a rigid primary portion, a rigid
secondary portion and a flexible portion interconnecting the rigid
primary portion and the rigid secondary portion. The mini-modules
19 and 21 carry various components 26, 28, 30, 32, 34 and 36 in
order to perform the intended avionics function of the LRM 20, as
discussed above. The particular function of the LRM 20 is outside
the scope of the present invention. However, a number of SEM-E LRMs
are known, including an MIL-STD-1750A processor, volatile and
non-volatile bulk memories, a MIL-STD-1553B bus interface
processor, as well as a DC-DC converter. Other types of SEM-E LRMs
are also known and described in the above military specification
which specifies and functions as well as the pin assignments for
each type SEM-E LRM.
[0021] The various components 26-36 on the rigid primary portions
22-24 are connected to a data bus, for example, an ARINC 659 data
bus as discussed below. The ARINC 659 data bus is a backplane
connected data bus. The ARINC 659 data bus may be configured as a
serial, two-wire data bus used for interconnecting all of the LRMs
within a single LRM chassis (not shown).
[0022] Each of the rigid primary portions 22 and 24, as best
illustrated in FIG. 2, are adapted to carry various components
forming the LRM. As shown best in FIG. 2, the component side of
each of the rigid primary portions 22 and 24 face outwardly. The
spacing between the rigid primary portions 22 and 24 and the
configuration with the component sides facing outwardly enables a
frame member 38, forming a part of the chassis (not shown), to be
sandwiched between the two rigid primary portions 22 and 24. The
frame member 38 may be formed as a heat sink to passively conduct
heat generated by the various components 26-36 on the rigid primary
portions 22 and 24 away from the LRM 20 to reduce the overall
operating temperature of the LRM 20.
[0023] An important aspect of the invention is the connection
between the rigid primary portions 22 and 24 and the backplane
contacts 40 (FIG. 2) forming the data bus. More particularly,
referring to FIG. 1, each rigid primary portion 22, 24 is
interconnected to a pair of rigid secondary portions 42, 44, 46, 48
configured to be generally parallel to the rigid primary portions
22 and 24 and connected to the rigid primary portions 22 and 24 by
way of flexible interconnecting portions 50, 52, 54, 56,
respectively. The rigid secondary portions 42, 44, 46, 48 provide
for dual-sided interconnections between the backplane contacts 40
and the rigid secondary portions 42, 44, 46, 48 as best shown in
FIG. 2. Such a configuration provides for generous interconnect
spacing for the various connections to the backplane contacts 40.
For example, exemplary spacing between contacts in a configuration,
as discussed above, for 472 backplane contacts 40 is 0.071 inches
center to center between contacts.
[0024] The flexible interconnecting portions 50, 52, 54, and 56,
are contiguous to the rigid primary portions 22, 24 and the rigid
secondary portions 42, 44, 46, and 48 and provide a continuous
electrical circuit path between the components 26-37 and the
backplane contacts 40. The flexible interconnected portions 50, 52,
54, and 56 may be formed with an offset relative to the rigid
secondary portions 42, 44, 46, and 48 and the primary rigid
portions 22, 24 as best shown in FIG. 2.
[0025] As best shown in FIG. 2, the backplane contacts 40 are
carried by an insulator body 56 covered with an EMI shield 58. The
insulator body 56 forms a part of the LRM chassis (not shown). The
chassis, however, does not form a part of the present invention.
The backplane contacts 40 may be configured to form four insertion
bays to correspond with the rigid secondary portions 42, 44, 46,
and 48. Each insertion bay is formed with a pair of opposing guides
62, 64 formed adjacent opposing ends of each row of backplane
contacts 40 forming the insertion bay. The guides 62, 64 are formed
with slots for receiving the rigid secondary portions 42, 44, 46,
and 48 and aligning the contact pad 60 on the rigid secondary
portions 42, 44, 46, and 48 relative to the backplane contacts
40.
[0026] As mentioned above, the rigid secondary portions 42, 44, 46,
and 48 are configured for dual-sided connections with the backplane
contacts 40. Thus, as best shown in FIG. 2, the backplane contacts
40 are formed in rows. More specifically, four pairs of rows of
backplane contacts 40 are formed. Each pair of rows of backplane
contacts 40 forms an insertion bay for receiving a dual-sided,
rigid secondary portions 42, 44, 46, and 48. The rigid secondary
portions 42 and 44 are provided with a plurality of contact pads,
generally identified with the reference numeral 60, for enabling
electrical interconnection with the backplane contacts 40.
[0027] The backplane contacts 40 may be formed with a bend at the
upper end, with the ends diverging outwardly as shown in FIG. 2.
Such a configuration for the backplane contacts 40 provides good
electrical contact between the backplane contacts 40 and the
contact pads 60 on the rigid secondary portions 42, 44, 46, and 48.
The backplane contacts 40 may be soldered to the contact pads 60
for good electrical connection to the backplane contacts 40.
[0028] The use of the flexible interconnecting portions 50, 52, 54
and 56 provides compensation for thermal, as well as vibrational,
stress. The use of the flexible interconnecting portions 50, 52, 54
and 56 also provides compensation for differences of the tolerances
in the locations of the different components forming the connector
system. FIG. 2 illustrates an embodiment in which a single flexible
interconnecting portion 50, 52, 54 and 56 is connected to a single
rigid secondary portion 42, 44, 46 and 48. FIG. 3 illustrates an
alternate embodiment in which a pair of flexible interconnecting
portions 70, 72 are connected to each of the secondary portions 42,
44, 46 and 48. The configuration of FIG. 3 can eliminate the need
for vias on the rigid secondary portions 42, 44, 46 and 48.
[0029] FIGS. 4 through 6 illustrate an alternate embodiment of the
LRM illustrated and described above which includes four
mini-modules or quarter modules. The quarter modules are virtually
the same as the mini-modules 19 and 21 discussed above and
illustrated in FIG. 1 and can be configured as illustrated in FIGS.
2 and 3.
[0030] The LRM having four quarter modules is generally identified
with the reference numeral 100 and includes four quarter modules
102, 104, 106 and 108 (FIGS. 2 and 4 through 6). The quarter
modules 102, 104, 106 and 108 are separated a frame 110 (FIG. 6)
which separates the quarter modules 102 and 104 from the quarter
modules 106 and 108.
[0031] As best shown in FIG. 6, the quarter boards 102, 104, 106
and 108 and the frame 110 are assembled together by way of pair of
spaced apart core plates 114 and 116. Each core plate 114 and 116
is formed to length to accommodate two quarter modules 102, 104,
106 and 108. Two quarter modules 102 and 104 are assembled to one
side of the frame 110 while the remaining two quarter modules 106
and 108 are assembled to the opposing side of the frame 110.
[0032] The frame 110 is provided with a plurality of apertures 113.
The apertures 113 are adapted to be aligned with corresponding
apertures 118 formed in the core plates 114 and 116 to enable the
quarter modules 102, 104, 106 and 108 to be assembled to the frame
110 with suitable fasteners 112. The core plates 114 and 116 are
provided with additional apertures 120 which, in turn, allow a pair
of covers 122 and 124 (FIG. 5) to be secured to the frame 110 and
the core plates 114 and 116 with suitable fasteners 126 to form an
assembly in accordance with the present invention.
[0033] Obviously, many modifications and variations of the present
invention are possible in light of the above teachings. Thus, it is
to be understood that, within the scope of the appended claims, the
invention may be practiced otherwise than as specifically described
above.
* * * * *