Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
1998-09-08
2001-07-03
Abrams, Neil (Department: 2839)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
C439S569000
Reexamination Certificate
active
06255588
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an enhanced arrangement for supplying power to a circuit board, and in particular, to an enhanced arrangement for supplying power to a backplane of a computer using a buss bar.
2. Background Information
Backplanes are wiring boards used, for example, in computers, and are typically provided with card slots or plugs for receiving various circuit boards, such as a processor card and a so-called memory riser card, attached to a common surface of the backplane by way of the card slots or the plugs. Further, it is typical to permanently attach a clock card, which is a further type of circuit board, and various electrical components, to the backplane. This assembly of the backplane, electrical components, and circuit boards may be positioned within an open cage, which is a frame fixed within a computer housing. The cage serves to position the circuit boards within the computer housing.
The various electrical components located on the backplane and cards (for example, the Dual In-Line Memory Modules (DIMMs) on the memory riser card) tend to consume a substantial amount of electrical power. In order to supply the electrical components with power, it is conventional to electrically connect the backplane to an external power supply. The backplane distributes the power received from the external power supply to the appropriate electrical components in a manner which will be subsequently described.
Backplanes are conventionally comprised of a plurality of superposed, laminated and alternating layers of conductive and insulative materials. The layers are each formed in discrete planes. For example, and referring to
FIG. 1
, a typical backplane
8
may have one or more internal wiring planes (i.e., a set of wirings located in one plane), each of which includes a number of individual conductive wirings
10
(also known as “traces”). The wirings are used to interconnect various electrical components and/or cards (not shown) locatable on the backplane
8
together, and allow the transmission of electrical signals.
Further, the backplane
8
will also typically include one or more power planes
12
, which are typically sheets of conductive material, such as copper. The power planes are used to supply power from the backplane
8
to the various electrical components and/or cards located on the backplane
8
.
Each of the conductive layers of backplane
8
are separated from the other conductive layers by a respective layer of insulating material. In
FIG. 1
, the power plane
12
is located beneath the plane of conductive wirings
10
. Only a portion of the power plane
12
and conductive wirings
10
is shown for clarity of illustration.
Typically, the backplane
8
will be provided with a number of plated vias
14
,
16
(i.e., holes plated or filled with a conductive material). Each via is electrically coupled to a respective internal power plane
12
or a respective wiring
10
. The power is typically transmitted within the backplane
8
, through the plating of the vias
14
, through the respective internal power plane
12
, and to the associated electrical components and/or cards. Likewise, the electrical signals are transmitted through the plating of the respective vias
16
, through the respective wirings
10
, and to an associated electrical component and/or card. As will be appreciated, to prevent shorting, it is important that the respective vias are only coupled to their associated corresponding wiring or power plane.
Further, in order to connect the backplane
8
to the external power supply, it is conventional to utilize a buss bar
18
(also known as a busbar or bus), such as is shown in
FIG. 2. A
buss bar is typically a heavy, rigid, metallic conductor, used to carry a large current and/or to make a common connection between several circuits. In the computer field, the buss bar is conventionally a relatively large, rectangular-shaped plate, composed of two conductive layers
20
,
22
separated by a dielectric layer
24
, for example. The conductive layers
20
,
22
can be copper, with one of the conductive layers
20
being used to transmit power from an external power supply
25
to the backplane
8
, and the other of the conductive layers
22
serving as a ground for the backplane. The advantages of a buss bar, as opposed to using a number of individual power transmission wires, each of which would be connected to the external power supply
25
and to a respective electrical connector, are well known to those skilled in the art. Such advantages include, for example, an organized power transmission scheme, due to the elimination of the power transmission wires, and a reduction in undesirable electrical noise, which may be generated when using a number of individual power transmission wires.
Typically, one edge of the buss bar
18
is provided with a plurality, for example, five sets, of conductive tabs
26
,
26
′, each of which plugs into a corresponding electrical connector
28
that is connectable to the back plane
8
. Various views of a conventional electrical connector
28
are shown in
FIGS. 3-6
. These electrical connectors
28
can be so-called solder tail power receptacles, (as illustrated) or C/P(compliant pin) power receptacles, for example, and will typically be provided with a plurality of pins
30
. The pins
30
are arranged to be in registration with, and insertable into, a corresponding number of the plated vias
14
formed in the backplane
8
.
Once the buss bar
18
is connected to the power supply
25
(in any conventional manner), and connected to the respective electrical connectors
28
, the power will be transmitted through the conductive layer
20
of the buss bar
18
, through the respective conductive tabs
26
of the buss bar, through the respective electrical connectors
28
, and into the corresponding vias
14
. Thereafter, the power is transmitted to the associated electrical components and/or cards in the manner previously described. To complete the circuit, the current travels back through a so-called ground plane, through the respective electrical connectors
28
, through the respective conductive tabs
26
′ of the buss bar, and back to the negative terminal of the power supply
25
, for example.
As will be appreciated, the use of power receptacles
28
requires that the associated vias
14
be positioned with predetermined spacings, so as to accommodate the pins
30
of the power receptacles. For example, if a power receptacle
28
has five pins
30
arranged in sequence, then there must be five vias
14
arranged in the same sequence, and with the same spacing, as the pins. Further, since the buss bar
18
will often have a plurality of sets of conductive tabs
26
,
26
′, for example, five sets of conductive tabs, linearly arranged along its edge, then there will typically be a like-number of power receptacles
28
arranged in a similar manner, so as to receive the respective conductive tabs therein. This will require a proportional number of vias
14
to be prearranged in the backplane
8
, to accommodate the respective pins
30
of the respective power receptacles
28
.
This arrangement of the vias
14
may disadvantageously interfere with the placement of the various wirings
10
formed on or in the backplane
8
. For example, if a via
14
is placed in the path of a wiring
10
, then the wiring
10
may need to be diverted around the via
14
to ensure its continuity. Stated alternatively, the positioning of the tabs
26
,
26
′ on the buss bar
18
will dictate where the vias
14
are located, and the positioning of the vias
14
will control the arrangement of the various wirings
10
on the backplane
8
. However, this may entail additional costs in planning and designing the layout of the backplane
8
, and require additional steps during the manufacturing of the backplane to ensure that the wirings
10
avoid the vias
14
. Further, in order to avoid the placement of the vias
14
, wirings
10
may be required to have
Abrams Neil
Berdo, Jr. Robert H.
International Business Machines - Corporation
LandOfFree
Arrangement for supplying power from a buss bar to a circuit... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Arrangement for supplying power from a buss bar to a circuit..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Arrangement for supplying power from a buss bar to a circuit... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2486998