This invention relates to electronic systems. In particular, the present invention is a backplane assembly for an electronic system chassis, wherein the backplane assembly incorporates connectors for a variety of printed circuit board modules in a multiple channel architecture.
The general construction and operation of electronic systems for an electronic device necessitates that a plurality of printed circuit board modules, such as input/output (I/O) modules be electronically connected to one or more central processing units. In order to achieve this electronic connection, each I/O module electronically contacts a mother board, often referred to as a backplane board as it is vertically mounted as a back wall of an electronic system chassis. The backplane includes a plurality of connectors for releasably interconnecting with a mating connector along a rear edge of each of the I/O modules. Typically, a pair of opposed side walls of the chassis incorporate guide channels for providing lateral support to the I/O modules when interconnected with the backplane.
For fail/safe operation, as may be necessary in electronic devices of aircraft systems, construction of the electronic system necessitates the use of redundant I/O modules. Typically, to achieve such redundancy requires the use of two chassis, with each chassis having an identical set of I/O modules. Each backplane of the redundant chassis would be linked to the electronic device through its own signal transmitting bus or channel. In other words, I/O modules of one chassis would be linked to the electronic device through a so called "channel A", while the redundant, second chassis would be linked to the electronic device through a so called "channel B". Operational failure of an I/O module within the one chassis would only require switching from the inoperative channel A to the operative channel B of the operational redundant, second chassis, to maintain the operation of the electronic device. One drawback of this redundant chassis architecture, particularly with regard to aircraft where space is at a premium, is the space requirement for the chassis of the redundant, second set of I/O modules.
U.S. Pat. No. 5,547,386 to Fredberg in one way, addresses this redundant chassis, space requirement drawback of redundant channel electronic systems. In Fredberg, a single chassis, having a single backplane incorporating redundant sets of connectors is used. The backplane connectors for the I/O modules are arranged side by side, with adjacent backplane connectors alternating between channel A and a channel B. Though the backplane architecture of Fredberg eliminates the added bulk of the redundant, second chassis, there are some disadvantages to the Fredberg design. For example, since only a single backplane is used, it is difficult to discern which I/O modules are on channel A and which are on channel B. This difficulty is particularly evident when inoperative or damaged I/O modules of an inoperative channel need to be identified for repair or replacement. In addition, due to the alternating nature of the channel A and channel B backplane connectors of Fredberg, I/O modules of a common channel can not be arranged side by side. Moreover, the backplane scheme of Fredberg can not accommodate "ganging" (i.e., connecting multiple I/O modules directly together) of like I/O modules.
There is a need for improved redundant channel, backplane assemblies for chassis of electronic systems. In particular, there is a need for a redundant channel, backplane assembly wherein I/O modules on channel A can be quickly discerned from I/O modules on channel B. This would allow I/O modules of an inoperative channel (inoperative due to inoperative or damaged I/O modules) to be readily identified with respect to the operative I/O modules of the operative redundant channel. In addition, the redundant channel, backplane assembly should permit I/O modules of a common channel to be arranged side by side, and should accommodate ganging of like I/O modules. Lastly, the redundant channel, backplane assembly should be as compact as possible so as to be particularly suitable for use in aircraft or wherever space is at a premium.