JPH10124211A - Board connection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a board connection device which can appropriately process a terminal that is not used, which is superior in resistance against noise and which can execute a stable operation only by connecting a circuit board. SOLUTION: For connecting the circuit boards 1, 2 and 3, the output buffers 302 and 303 of the circuit board 1 dealing with output signals which are possible to be not used from three state buffers. CPU 320 identifies the circuit board of an opposite party by IDR 307 and IDS 309 and controls the output buffer 302 or 303 of the signal which is not to be used in accordance with the result to an open (high impedance) state. The other end of the signal which is not to be used is grounded on the side of the circuit board 2 or 3. The input signal of the circuit board 1 is grounded on the side of the circuit board 2 or 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a board connecting device used for connecting circuit boards.

[0002]

2. Description of the Related Art With the development of electronic technology, electronic circuits have been reduced in size and weight, but the functions required of one electronic circuit board have been more and more increased in response to the diverse demands of users. .

[0003] For this reason, there is an increasing number of cases in which one basic electronic circuit board is formed and a board of another circuit section is connected to the board to add functions. As such a device configuration, for example, a configuration is known in which various interface cards and additional boards (such as a sound card and an Ethernet card) for realizing specific functions are mounted on a motherboard of a personal computer.

[0004]

In the above-described configuration, since various types of substrates are connected to one connector,
Depending on the type of the board, some of the signals assigned to the connector may be unused.

Conventionally, the processing of such unused signals differs depending on the input and output. For example, in many cases, a pull-up process or the like is performed on the input side substrate so that the input terminal of the circuit does not become open for input, and nothing is performed on the output end.

FIG. 1 shows an example of the above prior art.

In FIG. 1, reference numerals 1, 2, and 3 denote circuit boards connected to each other. Here, two examples of connecting the circuit boards 2 to 3 to the same circuit board 1 are shown. The circuit boards 1 and 2 or the connection portion between the circuit boards 1 and 3 is configured by a card edge connector or the like.

Further, α, β, and γ are circuit names in each circuit board. In the example shown in the figure, terminals α1, α2, and α3 in the circuit of the circuit board 1 correspond to terminals β1 and , Β2
It is connected to the. In the example shown in the lower part of the figure, the terminals α1, α2, α3 of the circuit board 1 are connected to the terminals γ1, γ2 of the circuit board 3. A, B, and C are signal names in the connector portion. Here, it is assumed that all signals are output from the circuit α to β or γ.

When the circuit boards 1 and 2 are connected, the signal C is not used, so that the circuit boards are open. Since the signal C is an output signal from α, there is almost no problem in normal operation even in the open state. On the other hand, when the circuit boards 1 and 3 are connected, since the signal B is not used this time, the signal B is open.

[0010] However, in the above-mentioned conventional configuration, the terminals which are not used as signals are not actually used at all.
In addition to wasting space, the patterns on the circuit board and the signal lines on the connector have become a kind of antenna and have a bad effect of increasing electromagnetic radiation noise.

In addition, digital circuits typified by recent microprocessors have been operating at high speeds and low voltages of several hundred megahertz, and from the standpoint of resistance to immunity noise, the addition of a ground point has made the circuit more stable. There is a desire for an increase.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a substrate connecting apparatus capable of appropriately processing unused terminals by simply connecting a circuit board, having excellent resistance to noise, and capable of performing stable operation. To provide.

[0013]

According to the present invention, there is provided a board connecting apparatus for connecting an electric signal between a plurality of circuit boards. In addition, a configuration is employed in which, when a connection is made between circuit boards, a control means for controlling an unused signal terminal generated by the connection to an open state and grounding according to the output of the identification means.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Basic Configuration) FIG. 2 shows the basic concept of the present invention, and corresponds to the configuration of FIG. 1 for connecting the circuit boards 1 and 2 or 1 and 3.

The circuit names, signal names, connection modes, and signal input / output directions are all the same as those in FIG. 1. The signal C is applied to the connection between the circuit boards 1 and 3, and the signal C is applied to the connection between the circuit boards 1 and 3. B is not used.

That is, in this configuration, the terminals α2 and α3 (signals B and C) of the circuit board 1 are used or not used depending on whether the other party is the circuit board 2 or 3.

Therefore, it is desirable for such a configuration to:
On the circuit board 1 side, switches SW1 to B and C are provided.
SW2 is provided, and when the signal is used, the signal line is connected to the terminal α2 or α3 by these switches. When not used, the signal line is grounded by these switches.

In the upper example of FIG. 2, since the circuit boards 1 and 2 are connected and the signal C is not used, SW2 is grounded. In addition, on the circuit board 2 side, this circuit board 1
Since it is obvious in advance that the signal C output from the circuit board is not used, a terminal for the signal C is provided in a card edge connector or the like, but this terminal is connected to the ground potential of the circuit board 2. In other words, both ends straddling the signal C connector are grounded.

On the other hand, in the upper example of FIG. 2, it is assumed that the signal B is used, and the switch SW1 is connected to the terminals α2 and β.
2 are connected.

In the example shown in the lower part of FIG. 2, the circuit boards 1 and 3 are connected, and the connection states thereof are reversed for the signals B and C. That is, since the signal B is not used this time, the switch SW1 is grounded, and the B terminal is also grounded on the circuit board 2 side. Since the signal C is used, SW1 connects α2 and C.

In the following embodiments, the above connection switching is realized by simply connecting the substrates.

(First Embodiment) FIGS. 3A and 3B show a structure in which a circuit board 2 or 3 is connected to a circuit board 1 in the first embodiment.

Here, the switches SW1 and S in FIG.
The function of W2 is realized by a three-state buffer of the output circuit of the circuit board 1.

In the figure, reference numeral 301 denotes an output buffer, which amplifies the signal A output from the terminal α1 and outputs the amplified signal A to the circuit board 2 (or 3).

Reference numerals 302 and 303 denote output buffers with output control, which are composed of three-state buffers.
Signals B and C output from the circuit board 1 are controlled respectively.

The three-state buffers constituting the buffers 302 and 303 have an open (high impedance) state as one of the output modes in addition to an output mode for performing a normal high / low level logic output.

The output mode of buffers 302 and 303, that is, a state in which a normal high / low level logic output is performed according to an input or an open state is selected by a signal from register 306. Register 30
6 is switched by a control signal from the CPU 320 mounted on the circuit board 1.

When the buffer 302 (303) is open, its output terminal becomes high impedance, and electrically the relationship between the signal line B (C) and the terminal α1 (α2) is determined by the switch shown in FIG. This is equivalent to switching to the lower side.

In FIGS. 3A and 3B, only the ground on the signal circuit board 2 or 3 side is shown, and a configuration corresponding to the ground circuit of the switches SW1 and SW2 in FIG. 2 is not shown. The configuration can be realized by using the embodiments described later.

Further, in FIG.
Is an input buffer to which a signal D or E from the circuit board 2 is input. These input circuits on the circuit board 1 side are grounded on the circuit board 2 or 3 side as shown in the figure.

Reference numeral 307 denotes an IDR (ID receiving device). The ID signal from the connected circuit block is transmitted to the CPU 320 of the circuit board 1. Reference numeral 308 denotes the circuit board 2
Is a central circuit γ of the circuit board 3.

Reference numeral 309 denotes an IDS (ID transmitting device) of the circuit board 2. The ID of the circuit board is transmitted to the circuit board 1. Reference numeral 311 denotes an IDS (ID transmission device) of the circuit board 3. The ID of the circuit board is transmitted to the circuit board 1.

In the present embodiment, the output mode of the buffers 302 and 303 by the register 306 is controlled by the CPU 320. In other words, the CPU 320
7 to communicate with the IDSs 309 to 311 and recognize the type (ID) of the other circuit board to determine the output mode of the buffers 302 and 303.

For example, in the case of FIG. 3A), the circuit boards 1 and 2 are connected. Since the output buffer 302 is in an output state according to a signal from the register 306,
Terminal α2 is transmitted as signal B to terminal β2.

The output buffer 303 is provided in the register 30.
6, the terminal α3 is grounded on the circuit board 2 side via the signal C.

The terminal α4 is directly connected to the terminal β3 of the circuit board 2 through the signal D. Since the input signal α5 is not used in the circuit board 2, it is grounded on the circuit board 2 side through the signal E.

On the other hand, in FIG. 3B), the circuit boards 1 and 3 are connected, and α2 is now in an open state and grounded at the circuit board 3 through the connector terminal B. The output buffer 303 is in an output state by a signal from the register 306, and the terminal α3 is connected to γ2 through the connector terminal C.

The terminal α4 is grounded on the circuit board 3 side through the signal D, and the terminal α5 is grounded on the circuit board 3 through the signal E.
At the terminal γ3.

The control of the CPU 320 is shown in the flowchart of FIG. FIG. 5 shows a table for performing control according to the IDs of the circuit boards 2 and 3.

This processing is started by power-on or the like in step S401.
320 sets the buffers 302 and 303 in an open state by setting a value in the register 306.

In step S403, the ID sent from the IDS 309 (or 311) of the circuit board to be connected is
Is received by the IDR 307 and transmitted to the CPU 320.

In step S404, using the ID received by the CPU, the control correspondence value of the referenced output terminal is acquired using the ID table of FIG.

In step S405, the control corresponding value is set in the register 306, and the output state of the corresponding output terminal is determined. The process ends in step S406.

FIG. 5 is a circuit diagram showing a circuit board I connected to the circuit board 1.
9 is an ID table defining how output signals B and C are set according to D.

As is clear from FIG. 5, when the circuit board 2 is connected, the buffer 302 handling the terminal α2 is set to the output state, and the buffer 303 handling the terminal α3 is set to the open state. When the circuit board 3 is connected, the buffer 302 that handles the terminal α2 is set to the open state, and the buffer 303 that handles the terminal α3 is set to the output state.

As described above, according to the circuit board connected to the circuit board 1, the output terminal whose use form can be changed is controlled by the three-state buffer, and the unused output terminal opens the buffer, and The corresponding signal lines are grounded on the circuit board 2 or 3 side. For unused input terminals, use circuit board 2 or 3
The corresponding signal line is grounded on the side.

Therefore, the output signal is not grounded as it is, but is grounded after opening the buffer of the unused output signal, so that the output buffer is not directly short-circuited to the ground potential. Electromagnetic noise can be reduced, and the ground point of unused circuits can be increased, thereby increasing the grounding point and improving the stability of the circuit, without causing problems that adversely affect the life and power consumption of the output buffer. .

(Second Embodiment) FIGS. 6 and 7 show a specific configuration of a connection portion of a circuit board. 6 and 7
Is based on the circuit configuration of FIG. 3 and uses the same signals as in FIG. In this embodiment, an unused signal terminal is grounded by the operation of a connection device such as a connector.

The connector section comprises a female receptacle 701 and a male plug 702 as shown in FIG. Here, the receptacle 701 is the circuit board 1 of FIG.
The plug 702 is on the circuit board 2 or 3 side in FIG.

Receptacle 701 and plug 702
Are provided with terminals for transmitting signals A to D as shown in FIG. The terminal on the receptacle 701 side is divided into two as shown, and the length of the terminal on the plug 702 side is of two types as described later. Here, only four sets of terminals are shown, and other terminals are omitted for simplification.

FIGS. 6a), 6c) and 6e) show P in FIG.
6B), FIG. 6D), FIG.
f) shows a cross-sectional structure along the R-S line in FIG. 7, respectively. 6a) and 6b) show the structure for the circuit board 2 of FIG. 3a), and FIGS. 6c) and 6d) show the structure for the circuit board 3 of FIG. 3b).

In the case of the circuit board 2, the signal A of the plug 702
6A) and FIG. 6B), and terminals 602, 60 for signals A, B and D.
3, 605 are short and the terminals β1, β2, β
3 respectively. Terminal 604 for signal C is long and grounded.

In the case of the circuit board 3, the signal A of the plug 702
The terminals for .about.D are as shown in FIGS. 6c) and 6d), and the terminals 606 and 608 for the signals A and C are short and are respectively connected to the terminals .gamma.1 and .gamma.2 of the substrate.
Terminals 607, 609 for signals B and D are long and grounded.

On the other hand, the structure on the circuit board 1 side is as shown in FIGS. 6E) and 6F). On both sides of the slot of the receptacle 701, terminals for connecting the above-mentioned short terminal and long terminal are provided. It is.

For example, for the signal B, the terminal 616
And 617 (which are insulated from each other), of which the terminal 616 on the back side of the slot is
02 for connection to the longer terminal (for example, 607). These are the terminals 615, 6 of the signals A, C, D.
Similarly, the terminals 615, 616, 620, and 621 on the back side of these slots are grounded on the circuit board 1 side as shown in the figure.

For the signal B, a terminal 617 provided in a U-shape so as to cover the upper end of the slot is provided with a plug 70.
2 for connection to the shorter terminal (for example, 603). These are the terminals 614, 61 of the signals A, C, D.
The same applies to the terminals 9 and 622.
4, 617, 619, and 622 are terminals α1, α2,
connected to α3 and α4. That is, these terminals 61
4, 617, 619, and 622 are used for input and output of signals.

In the above configuration, when the circuit board 2 is connected to the circuit board 1 (FIG. 6A), FIG. 6B), FIG.
FIG. 6f)) shows terminals 602 and 614 and terminals 603 and 61.
7, terminals 604 and 620, and terminals 605 and 622 are respectively connected.

Similarly, when the circuit board 3 is connected to the circuit board 1 (FIG. 6c), FIG. 6d), FIG. 6e), FIG. 6f))
Are terminals 606 and 614, terminals 607 and 616, terminal 6
08 and 619 and terminals 609 and 621 are connected, respectively.

The longer terminal 60 of the plug 702
The terminals 7 and 604 are also connected to the terminals 617, 619 and 622, and the output buffer (high impedance state) of the circuit on the circuit board 1 side is grounded. Regarding the terminal 609 (signal D), the terminals 621 and 622 are grounded by these terminals, and α4 of the circuit board 1 is connected to both sides of the circuit board to be connected.
Will be grounded.

By configuring the connecting portion as shown in FIGS. 6 and 7, an unused input or output terminal can be grounded only by connecting a connector, thereby reducing electromagnetic radiation noise and reducing unused unused terminals. By grounding the circuit, the number of ground points increases, and the stability of the circuit can be improved.

In particular, as for the signal to be grounded, for example, in the case of the signal B in FIGS. Of the circuit board, and the reliability and stability of the circuit can be improved.
The same applies to the input signal of. For example, FIG.
f) signal D).

When the structure of the first embodiment is used together, the signals α2, α3, and α4 are in a high impedance state, and if the structures of the first and second embodiments are used together,
The structure of the switches SW1 and SW2 in FIG. 2 is realized.

(Third Embodiment) FIG. 8 shows how the terminals of the connection portion are arranged in a configuration in which a terminal which is unused by a mating substrate is used as a ground circuit as shown in FIGS. FIG.

In FIG. 8, reference numeral 801 denotes a connector, on which terminals 802 to 809 are arranged. 80 of these
2, 804, 807, and 809 are signal terminals that are meaningful (used) when connected to the circuit board M.
3, 805, 806, and 808 are signal terminals that are meaningful (used) when connected to the circuit board N.

The terminals 802, 804, 807, and 809 are set to be in an operating state when connected to the circuit board M. At this time, the unused terminals 803, 805, 80
6 and 808 are grounded, for example, by the configuration described in the second embodiment as shown in FIG.

Conversely, when connecting to the circuit board N,
03, 805, 806, and 808 are activated, and the terminals 802, 804, 807, and 809 are grounded.

By arranging unused terminals in a staggered manner and grounding them by the structure in the above-described embodiment, the grounding circuits of the terminals of the connector are arranged in a staggered manner. The grounding circuit can provide a shielding effect both when connected to the circuit board M and when connected to the circuit board N. Even when transmitting a high-speed signal, radiation noise can be reduced and stable operation can be achieved. .

[0069]

As described above, according to the present invention,
In a board connection device for connecting an electric signal between a plurality of circuit boards, a means for identifying a mating circuit board to be connected, and an unused signal terminal generated by the connection according to an output of the identification means at the time of connection between the circuit boards. The open circuit and the grounding control means are used, so only by connecting the circuit board, unused terminals can be properly processed, and the life of the buffer element and the power consumption are adversely affected. There is an excellent effect that the electromagnetic radiation noise is reduced and the unused circuit is grounded to increase the number of ground points and improve the stability of the circuit without causing any problem.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a conventional board connection device.

FIG. 2 is a block diagram showing a basic configuration of the present invention.

FIG. 3 is a block diagram showing a first embodiment of the board connection device of the present invention.

FIG. 4 is a flowchart showing an operation in the configuration of FIG. 3;

FIG. 5 is an explanatory diagram showing a control data table used in the configuration of FIG. 3;

FIG. 6 is an explanatory view showing a second embodiment of the board connection device of the present invention.

FIG. 7 is a perspective view showing a second embodiment of the board connection device of the present invention.

FIG. 8 is an explanatory view showing a third embodiment of the board connection device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 2 Circuit board 3 Circuit board 301 Output buffer 302 Output buffer 303 Output buffer 304 Input buffer 305 Input buffer 306 Register 320 CPU 307 IDR (ID receiver) 309 IDS (ID transmitter) 311 IDS (ID transmitter)

Claims (4)

[Claims] 1. A board connection device for connecting an electric signal between a plurality of circuit boards, comprising: means for identifying a counterpart circuit board to be connected; and connection according to an output of the identification means at the time of connection between the circuit boards. A board connection device, further comprising control means for controlling an unused signal terminal to be opened and grounding the unused signal terminal. 2. The board connection device according to claim 1, wherein unused signal terminals of the circuit boards connected to each other are grounded by an operation of connection means of the circuit board. 3. A plurality of terminals for a predetermined signal of at least one of the connection means of the circuit boards connected to each other are provided along a connection operation direction, and one of the terminals is connected to a ground circuit, The board connection device according to claim 1, wherein the unused signal terminal is grounded by connecting a terminal of a corresponding connection means of the other circuit board to a terminal connected to the ground circuit. 4. The board connection device according to claim 1, wherein connection terminals that can be unused by a connection partner circuit board are arranged in a staggered manner.