JPH0590747A - Method for connecting printed circuit boards - Google Patents

Abstract

PURPOSE:To enable the wiring length for an interface signal to be reduced and the area of a printed circuit board needed for interfacing to be reduced when connecting printed circuit boards. CONSTITUTION:A through-hole 11 of a printed circuit board 1 and a through- hole 21 of a printed circuit board 2 are overlapped and an electrically conductive pin 7 is press-inserted into the overlapped through-holes 11 and 21, thus enabling signal lines of the two printed circuit boards to be connected electrically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention In the present invention, in a device using a printed board, the components must be mounted on both sides of the printed board due to the wiring length limitation. A method of connecting printed boards to each other when the device cannot be inserted into the rack's slod after mounting.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional example of a method for connecting printed boards to each other, which is an arithmetic processing unit which is inserted into a VMEbus subrack. 1 is a daughter boat, 2 is a motherboard,
12 is a stacking connector pin header, 22 is a stacking connector socket, and 4 is a daughter board 1.
Parts 5 and 5 are parts to be mounted on the motherboard. 1, a microprocessor, a cache memory, etc. are mounted.

In recent years, due to the widespread use of microprocessors adopting the RISC architecture, the operating clock of the microprocessor has exceeded 50 [MHz], and the access time to the cache memory has been shortened accordingly.
This path is often the critical path for delay time. At this frequency, considering the media delay from the microprocessor to the cache memory, the wiring length of the print pattern must be kept to a few cm, but the microprocessor, cache memory, and other parts should be installed on only one side of the printed board. If it is mounted, the pattern wiring length becomes long and the delay time becomes long. For this reason, components are mounted on both sides of the printed board, and the wiring length of the critical path is shortened to try to shorten the media delay time.

However, it is not necessary to simply mount it on both sides of the printed board as shown in FIG. 5, but if it is mounted as shown in FIG. 5, it will be inserted next to it when it is inserted into the VMEbus subrack. The component mounted on the back side of the other printed board that is going to be inserted into the other printed board comes into contact and cannot be attached to the subrack.

For these reasons, a portion where the wiring length is severely limited is formed into a daughter board and mounted on both sides of the printed board to suppress the increase in media delay of the critical path, and a portion where the wiring length is not strictly limited is placed on one side of the motherboard. By mounting it, it is possible to prevent it from touching the printed board in the next slot, and to interpose the pin header and the connector of the stacking connector between the daughter board and the motherboard so that they are electrically and mechanically connected. It is taking a different method.

[0006]

However, in the conventional method of connecting the printed board, the distance between the daughter board and the mother board becomes large due to the large capacity of the stacking connector, and the delay becomes large, so that the path of this path is reduced. It may become a critical path. For this reason, in a device that performs a synchronous circuit operation, it is necessary to insert a register before and after the stacking connector, and thus it is necessary to prevent the delay time from being exceeded.

Further, due to the limitation of the size of the stacking connector, an appropriate distance between the daughter board and the mother boat cannot be secured, and there are cases in which the VMEbus subrack must be occupied by two slots.

[0008] Therefore, a technical object of the present invention is to reduce the distance between the daughter board and the mother boat, and to obtain a method for connecting printed boards with each other without limiting the size of the stacking connector.

[0009]

According to the present invention, in a method of connecting printed boards which electrically connect printed boards having through-holes, the through-holes are kept in close contact with each other. There is provided a method for connecting printed boards to each other, which has a pin for electrically pressing.

[0010]

The first printed board has through holes for interfacing with the second printed board, and the second printed board has through holes for interfacing with the first printed board. When electrically connecting the first printed board and the second printed board, pins made of an electric conductor are pressed into the through holes of the first printed board and the through holes of the second printed board. , Connected.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a method of connecting printed boards according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram of a printed board according to an embodiment of the present invention, which is a side view of an arithmetic processing unit connected to a VMEbus. However, in the present invention, the number, arrangement, type, function, etc. of the parts are not important, so they are simply described.

A printed board 1 serving as a daughter board is equipped with a microprocessor 3 having a severe delay time in logic design and a random access memory 4 constituting a cache memory. The printed board 1 is divided into a group of parts having a high height (for example, a microprocessor with a heat sink, a tandem spring shunt) and a group of low parts (surface-mounted parts such as a random access memory buffer and a TTL) such as a latch. The high component is mounted on one surface (here, the A side), and the low component is mounted on the other surface (the B side, here). In particular, it is important to mount a component having a low component height on the B side in order to suppress the slot width occupied by the arithmetic processing unit when it is later connected to the mother board by the printed board 2 and becomes a complete arithmetic processing unit. ..

The printed board 2 serves as a mother board. Since only one side is mounted on the motherboard, it is not necessary to sort by the height of the parts, unlike daughter boards. 5
Shows the functional components such as location monitor, requester, master, interrupt handler, and backplane interface for VMEbus all together. That is, 5 is not made of one component, for example, an LSI such as a gate array, but includes standard logic such as TTL. Reference numeral 6 is a connector for connecting to the VMEbus backplane.

The printed board 2 is provided with holes so that the parts mounted on the printed board 1 do not hit when it is connected to the printed board 1. The printed board 1 and the printed board 2 are separately assembled, and the through hole 11 and the printed board 2 of the printed board 1 are stacked so that the printed board 1 is stacked on the printed board 2 and the pins 7 made of an electric conductor can be driven therein.
The position of the through hole 21 is aligned. FIG. 2 is an enlarged view of this overlapped portion. As is clear from FIG. 2, the present invention is characterized in that the distance between the printed board 1 and the printed board 2 is substantially zero. Pin 7
Is pressed into the through hole 11 and the through hole 21,
And 21 are electrically connected.

FIG. 3 is a perspective view of the overlapping portion of the printed board 1 and the printed board 2 as seen from above. Reference numeral 8 is a bolt and nut for more strongly and mechanically connecting the printed board 1 and the printed board 2, and is provided for completely locking. The distance between through holes is 100 as shown in Fig. 3.
[Mil] pitch = 2.54 [mm], square 100
It is also possible to make a through hole in the center of [mil]. When the stacking connector is used, the through holes can usually be formed only at the four corners of the square of 100 [mil], so that the area required for the inter-board interface is reduced in the present invention as compared with the case where the stacking connector is used. ..

[0016]

As described above, according to the present invention, the distance between the printed boards becomes close to zero, the media delay becomes small, and the number of through holes per unit area can be increased, so that the area required for the interface can be reduced. be able to.

Further, in the VMEbus, the thickness of the mother board is specified to be 1.6 [mm], and the length of the lead that may project to the back surface is specified to be 1.5 [mm]. According to the present invention, conventionally, when mounting a component on the back surface, the component height was limited to 1.52 [mm], but by mounting the component on the rear surface of the daughter board, 1.6 + 1.
The limit is loosened up to 52 = 3.12 [mm].

[Brief description of drawings]

FIG. 1 is a diagram illustrating a method of connecting printed boards to each other according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a connecting portion between printed boards in FIG.

FIG. 3 is an enlarged view of a portion where printed boards overlap each other.

FIG. 4 is a diagram for explaining a conventional example of a method of connecting printed boards to each other.

FIG. 5 is a side view when components are mounted on both sides of a printed board.

[Explanation of symbols]

 1, 2 Printed board 3 Microprocessor with heat sink 4 Static memory 5 Parts to be mounted on printed board 6 Backplane connector, 7 pins 8 Bolt nut 11,21 Through hole 12,22 Stacking connector

Claims (2)

[Claims] 1. A method of connecting printed boards, wherein printed boards having through holes are electrically connected to each other, comprising a pin for electrically pressing the through holes in a state where the through holes are in close contact with each other. A method for connecting printed boards to each other, which is characterized in that 2. The method for connecting printed boards to each other according to claim 1, wherein one printed board is a motherboard on which components can be mounted on only one surface, and the other printed board can be mounted on both surfaces. A method for connecting printed boards to each other, which is a daughter board.