GB2243247A

GB2243247A - Printed circuit board assemblies

Info

Publication number: GB2243247A
Application number: GB9104525A
Authority: GB
Inventors: Mark Stephen Andrews
Original assignee: Fujitsu Services Ltd
Current assignee: Fujitsu Services Ltd
Priority date: 1990-04-20
Filing date: 1991-03-04
Publication date: 1991-10-23
Anticipated expiration: 2011-03-04
Also published as: GB9104525D0; GB9008930D0; GB2243247B

Abstract

A printed circuit board (PCB), assembly provides an interface between a computer bus and a local area network (LAN). The PCB assembly comprises a motherboard (10) carrying components for implementing the LAN protocol, and a daughterboard (11) carrying components for implementing the physical LAN interface. The daughterboard under the control of guides (17) slides into a cut-out recess (16) in the motherboard, and is located in the plane of the motherboard. A different LAN interface can be provided simply by plugging in a different daughterboard. Electrical connection between boards is provided by connectors (19, 20). <IMAGE>

Description

Printed Circuit Board Assemblies Background to the invention This invention relates to printed circuit board (PCB) assemblies. The invention is particularly, although not exclusively, concerned with a PCB assembly for providing a local area network (LAN) interface unit for a computer system.

Such a LAN interface unit may be required to implement one of a number (n) of different LAN protocols, and to interface with one of a number (m) of different physical LAN types. As a result, it may be necessary to provide a large number (n x mj of different PCB types, one for each possible combination of LAN protocol and physical type.

More generally, there exists a problem of providing a range of different PCB assemblies to allow for a number of different options.

The object of the present invention is to provide a PCB assembly which facilitates the provision of such options.

Summary of the invention According to the present invention, there is provided a printed circuit board assembly comprising (a) a motherboard having a cut-out recess extending from one edge of the motherboard, (b) a daughterboard, (c) guide means adjacent to said recess for guiding the daughterboard into the recess from the edge of the motherboard, in the plane of the motherboard, and (d) connection means for providing electrical connections between the motherboard and daughterboard.

It can be seen that a PCB assembly in accordance with the invention can be modified simply by exchanging a plug-in daughterboard. This allows a relatively large number of different options to be provided using a relatively small number of motherboard and daughterboard types. Moreover, since the daughterboard is positioned in the plane of the motherboard, the thickness of the assembly is not increased, so that it can be inserted into a standard slot in a computer system.

Brief description of the drawings Figure 1 is a plan view of the PCB assembly in accordance with the invention.

Figure 2 shows a guide forming part of the PCB assembly.

Figure 3 is a sectional end view of the guide.# Description of an embodiment of the invention One PCB assembly in accordance with the invention will now be described by way of example with reference to the accompanying drawings.

The PCB assembly is a LAN interface unit, for interfacing between the internal system bus of a computer and a local area network.

Referring to Figure 1, the PCB assembly comprises a motherboard 10 and a daughterboard 11. The motherboard 10 carries circuit components 12 for implementing a particular LAN protocol, while the daughterboard 11 carries circuit components 13 for providing the required physical interface to the LAN.

These components 12, 13 and the connections between them may be conventional and so will not be described in further detail.

The PCB assembly is designed to fit into a standard expansion slot in a conventional computer cabinet. The assembly is inserted into the slot in the direction indicated by the arrow 14, and when the assembly is fully inserted, a connector 15 on the motherboard 10 mates with a corresponding connector (not shown) in the computer cabinet, so as to form the required electrical connections between the assembly and the internal bus of the computer.

The motherboard 10 has a cut-out recess 16 extending from one edge of the board. Two guides or runners 17 are mounted on opposite sides of this slot.

The daughterboard 11 slides into the guides 17 in the direction of the arrow 18. When the daughterboard 11 is fully inserted, as shown in Figure 1, it is located in the recess 16, in the plane of the motherboard 10. A connector 19 on the daughterboard mates with a corresponding connector 20 on the motherboard, so as to form the required electrical connections between the boards 10, 11.

The daughterboard 11 also carries a bracket 21 at its outer end. This bracket carries a connector 22 for providing the physical connection to the LAN.

For example, the connector 22 may be a co-axial socket, or a fibre optic connector, depending on the physical LAN type.

Referring now to Figures 2 and 3, these show one of the guides 17 in more detail.

The guide 17 comprises a generally H-section plastic strip, having two channels 30 and 31. The channel 30 is designed to be attached to the motherboard, along the edge of the recess 16. The channel 31 is designed to receive the daughterboard, so as to guide it into the recess.

Portions of the wall of channel 30 are cut away, to form two resilient fingers 32 on each side of the channel. Each of these fingers 32 carries a raised portion 33 on its inner face. The channel 30 is pressed on to the motherboard, along the edge of the recess 16, so that the raised portions 33 snap into corresponding holes 34 (Fig. 1) in the motherboard, holding the guide in place.

The central portion of the guide, between the channels 30, 31 has a resilient tongue 35 extending into the channel 31, for ensuring that the daughterboard is correctly aligned with the recess 16 so that the connectors 19, 20 are properly aligned with each other.

It can be seen that the PCB assembly described above can easily be modified, by removing the daughterboard 11 and plugging in a new daughterboard.

Claims

1. A printed circuit board assembly comprising (a) a motherboard having a cut-out recess extending from one edge of the motherboard, (b) a daughterboard, (c) guide means adjacent to said recess for guiding the daughterboard into the recess from the edge of the motherboard, in the plane of the motherboard, and (d) connection means for providing electrical connections between the motherboard and daughterboard.

2. An assembly according to claim 1 wherein the motherboard carries a connector for providing an electrical connection with a computer bus.

3. An assembly according to either preceding claim wherein the motherboard carries circuit components for implementing a local area network protocol.

4. An assembly according to claim 3 wherein the daughterboard carries circuit components for implementing a physical local area network interface.

5. An assembly according to claim 4 wherein the daughterboard also carries a connector for providing physical connection to the local area network.

6. A printed circuit board assembly substantially as hereinbefore described with reference to the accompanying drawings.