Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With mating connector which receives panel circuit edge
Reexamination Certificate
2000-07-27
2001-12-11
Patel, Tulsidas (Department: 2839)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With mating connector which receives panel circuit edge
C361S788000
Reexamination Certificate
active
06328572
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a control board for industrial equipment where a microcomputer is applied, and more particularly to a configuration of a motherboard for buses which have a bus line between boards having various functions, and the connector structure thereof.
BACKGROUND OF THE INVENTION
A mother board for a bus for connecting many functional boards, such as an I/O board, memory board and CPU board (these boards connected to a motherboard are called “daughter boards”) via connectors, and performing communication between these daughter boards are widely used for many industrial equipment including measurement control equipment and medical equipment. The standard for buses used for motherboards have been specified in such industrial standards as the IEEE standard and the ICE standard, and various motherboards for buses, such as a motherboard for a VME BUS and a motherboard for a CPCI BUS conforming to these standards have been commercialized according to the size of the board to be connected and the number of slots.
In such a motherboard for a bus (also called a “backplane” or “backboard”), high frequency control signals flow over a bus line formed on the motherboard. In a recent system, in particular, the number of bits, which is the processing unit of a microcomputer, increased from 16 bits to 32 bits to 64 bits, with control signals increasing in speed and frequency as the reference clock speed increases. As a result, transmitted high frequency signals reflect on the bus line, and this reflection component is superimposed on control signals as noise, interfering with the stable operation of the system. To prevent this in a motherboard for a bus which performs high-speed communication processing, a high-speed Schottky diode array (terminating resistance) is mounted next to the last slot on the bus line to absorb high frequency signals so that reflection noise is not generated on the bus line.
However, mounting the above terminating resistance on a motherboard increases the number of components to be mounted on the motherboard, and as a result, the mounting space of conventional components, such as connectors for board connections, capacitors and terminals, decreases, or the size of the motherboard increases.
A solution to this problem is creating a small board with a terminating resistance in the same way as other daughter boards, and this small board is inserted in the last slot on the motherboard. With this solution, however, a small board with a terminating resistance (termination board) occupies the last slot on the motherboard, which decreases the number of available slots for actual operation.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a motherboard where a terminating resistance can be installed without decreasing the mounting space of the motherboard or increasing the size of the motherboard.
It is another object of the present invention to provide a motherboard where a terminating resistance can be installed without decreasing the number of available slots.
To achieve these objects, a motherboard according to the present invention comprises a plurality of connector elements (e.g. plug connector
12
) installed on a front face of the board and a bus line for inter-connecting these plurality of connector elements, so as to allow inter-connection of a plurality of daughter boards connected to the plurality of connector elements. In the motherboard, a termination board having a terminating resistance to decrease reflection noise of the bus line is connected to the connector element at the last stage of the bus line among the plurality of connector elements installed on the front face of the motherboard.
According to the above configuration, a terminating resistance (high-speed Schottky diode array), which is conventionally installed next to the last slot of a motherboard, is installed on the termination board, and is connected to the connector element at the last stage of the bus line, just like another daughter board. Since the terminating resistance is removed from the motherboard, the mounting space for other components can be increased, or the size of the motherboard can be decreased.
Another motherboard according to the present invention comprises a plurality of connector elements installed on a front face of the board and a bus line for inter-connecting these plurality of connector elements, so as to allow inter-connection of a plurality of daughter boards connected to the plurality of connector elements, just like the above invention. In the motherboard, a connector element (e.g. plug connector
15
), where a termination board having a terminating resistance for decreasing the reflection noise of the bus line is connected, is installed on the rear face of the connector element at the last stage of the bus line among the plurality of connector elements installed on the front face of the motherboard.
According to this configuration, a terminating resistance, which is conventionally installed on the motherboard, is installed on the termination board, and the termination board is connected to the connector element installed on the rear face of the connector element at the last stage of the bus line, just like another daughter board. Since the terminating resistance is removed from the motherboard, the mounting space for other components can be increased or the size of the motherboard can be decreased. Also, according to the present configuration, the termination board does not occupy the termination slot mounted on the front face of the motherboard, so all the slots on the front face of the motherboard can be used for connecting daughter boards, therefore slots can be effectively used.
It is preferable that the termination board to be connected to the motherboard is installed such that the component mounting face of the board of the termination board is parallel with the other daughter boards to be connected to the motherboard. According to this configuration, the termination board is installed parallel with the other daughter boards, so the termination board does not interfere with mounting the other daughter boards, and the dimension in the width direction (dimension in the array direction of the plurality of slots) of the system having this motherboard can be decreased, and a compact system can be provided.
When the connection terminal of the termination board is installed on the rear face of the motherboard, it is preferable that the termination board to be connected to the motherboard is configured such that the component mounting face of the board of the termination board is parallel with the motherboard. According to this configuration, the termination board does not protrude to the rear face side of the motherboard, therefore the dimension in the depth direction to the rear face side of the motherboard (thickness direction of the system) can be decreased, and a compact system can be provided.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 3992686 (1976-11-01), Canning
patent: 4420793 (1983-12-01), Strandberg
patent: 4498717 (1985-02-01), Reimer
patent: 4511950 (1985-04-01), Bunner et al.
patent: 4647123 (1987-03-01), Chin et al.
patent: 5117331 (1992-05-01), Gebara
patent: 5391922 (1995-02-01), Matsui
patent: 5525063 (1996-06-01), McMichen et al.
patent: 5530623 (1996-06-01), Sanwo et al.
patent: 5547386 (1996-08-01), Fredberg
patent: 5583867 (1996-12-01), Poole
patent: 5887158 (1999-03-01), Sample et al.
patent: 5896473 (1999-04-01), Kaspari
patent: 5926378 (1999-07-01), DeWitt et al.
patent: 6003131 (1999-12-01), Iee et al.
patent: 6018867 (2000-0
Higashida Hiroshi
Makino Kimiyasu
KEL Corporation
Patel Tulsidas
Usher Robert W. J.
LandOfFree
Motherboard with board having terminating resistance does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Motherboard with board having terminating resistance, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motherboard with board having terminating resistance will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2598879