JP2603869Y2 - Bus line equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bus line (common bus) serving as a main transmission path of a signal in an electronic computer or a communication device, and more particularly to an apparatus which can connect peripheral circuits in a live state. Related.

[0002]

2. Description of the Related Art Generally, in electronic equipment, signals are exchanged between a plurality of circuits or devices via a common transmission line. This common transmission path is called a bus line.
FIG. 3 shows a conventional bus line. The bus line 1 is provided on a back board 2 which is a single printed board, and includes a plurality of circuit packages 2 and 2 on which peripheral circuits are mounted.
The two are interposed and connected. Terminating resistors 4 and 4 are interposed at both ends of the bus line 1. Signals are exchanged between the bus line 1 and the circuit package 2 via a driver circuit 5 and a receiver circuit 6 provided together with peripheral circuits in the circuit package 2.

[0003]

In the conventional bus line device, while the bus line 1 is energized, the circuit package 2 connected to the bus line 1 is removed, or a new circuit package 2 is connected to the bus line 1. , There is a problem that the signal on the bus line is disturbed. This is because the electrical characteristics of the signal path are changed by inserting and removing the circuit package 2 in a state where a signal is flowing. The effect is particularly remarkable when a new circuit package 2 is inserted. is there.

When a new circuit package 2 is inserted,
As shown in FIG. 4, the state becomes the same as the case where the stray capacitance 7 corresponding to a capacitor is suddenly connected to the driver circuit or the receiver circuit, and the moment the circuit package 2 is inserted, the bus line 1 is short-circuited by the capacitor ground circuit. Is done.
Therefore, an error occurs in the data flowing on the bus line 1 at the moment when the circuit package 2 is inserted. As described above, there is no conventional bus line that can withstand insertion and removal of the circuit package 2 in a live state.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to provide a bus line device which can withstand insertion and removal in a live state.

[0006]

In order to solve the above problems, in the present invention, the exchange of signals between circuits is common.
Bus line equipment that is connected via a bus line
Control signals from the bus lines and peripheral circuits
To turn the output on, off, and open.
Multiple signals received from the circuit side and sent to the bus line
Between the driver circuit and the control terminal of the driver circuit and ground
In response to the ground resistance provided and the signal from the bus line
Multiple receiver circuits for sending to peripheral circuits and peripheral circuits
With a connector to connect to the motherboard to be connected
Are provided on the same board, and the driver circuit and
Connect the power terminal and ground terminal to the
The grounding resistor has one terminal connected to the driver circuit.
Connected to the control terminal and the other terminal to the ground terminal.
Power and ground from the motherboard via the connector.
The supplied bus line device was configured.

[0007]

According to the bus line device of the present invention, even if the bus line is energized regardless of the connection state of the circuit package,
Since the peripheral circuit is connected to the bus line via a driver circuit and a receiver circuit corresponding to a buffer circuit, signals on the bus line are not disturbed by connection or separation of the peripheral circuit. Further, since the bus line is connected to the motherboard via the connector, the bus line can be replaced even when the bus line fails.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, a bus line device according to this embodiment includes a bus line 11, a terminating resistor 12 connected to both ends of the bus line 11, a plurality of driver circuits 13 connected along the bus line, and a driver. The control terminal of the circuit 13
It comprises a ground resistor 19 provided between the ground terminals and a receiver circuit 14 (only one is shown in the figure and others are omitted, but a plurality of circuits are actually connected at equal intervals). The bus line device is provided on one print board, and forms a bus line package 10.

As shown in FIG. 2, the bus line package 10 has a plug connected to a connector 10a at one end thereof, and is connected to the motherboard B by the connector 10a. The bus line package 10 includes a power supply S
, A ground line E, and input / output terminals A to D of each driver circuit 13 and receiver circuit 14.

FIG. 2 shows a state in which the bus line package 10 is mounted on the motherboard B of the apparatus main body. Here, the bus line package 10 and each circuit package 15 are mounted on the motherboard B to constitute the device. The bus line package 10 is disposed on the opposite side of each circuit package 15 with respect to the motherboard B, and is connected to a portion of each circuit package 15 where the pin 15b of the connector 15a does not exist via the bus line package connector 10a. .

The bus line package 10 of this embodiment is
When mounted on the motherboard B as shown in FIG. 2, the driver circuit 13 and the receiver circuit 14 are also energized regardless of the connection state of each circuit package 15. The input impedance of the receiver circuit 14 is always high. The output of the driver circuit 13 has three states: on, off, and open. When the high-level signal voltage is not applied to the terminal C, the output of the driver circuit 13 is in an open state. Motherboard the bus line package 10
At the time of mounting on the driver B, the control terminal of the driver circuit 13
Since the driver circuit 13 is grounded via the ground resistor,
The output is open. The driver circuit 13 and the receiver circuit 14 in this state are connected to the peripheral circuits in the circuit package 15 via the bus line package connector 10a, the motherboard B, and the circuit package connector 15a.

When each peripheral circuit sends a signal to another peripheral circuit via the bus line 11, the bus line package 10
Is set to a high level, a signal is sent from the terminals A and B at the same time. Each peripheral circuit receives a signal from the bus line 11 via an output terminal D of the receiver circuit 14.

As described above, in the present invention, since the circuit in the circuit package 15 and the bus line 11 are connected via the driver circuit 13 and the receiver circuit 14, they function as a buffer. Therefore, the state of the circuit of the circuit package 15 does not directly affect the operation of the bus line, including the insertion and removal of the package.

The motherboard B has a circuit package 1
When the state of the circuit in the circuit package 15 is unstable, for example, immediately after the connector 15a of No. 5 is inserted, a random signal voltage may be applied to the terminals A, B, and C. However, this problem can be prevented by appropriately providing a well-known circuit such as a power-on clear having a function of maintaining the state of this signal for a certain period of time after the circuit package 15 is inserted therein.

[0016]

As described above, according to the present invention, a bus line, a driver circuit for sending a signal to the bus line, and a receiver circuit for receiving a signal from the bus line are integrally provided on a base, and a circuit package is provided. The peripheral circuit is connected to the bus line via a driver circuit and a receiver circuit corresponding to a buffer circuit, and the bus line is inserted and removed in a live state. It does not affect the above signal. Furthermore, by connecting the bus line package to the motherboard via a connector, the bus line package can be easily replaced even in the event of a failure, and is frequently used in transmission equipment that frequently disconnects and separates peripheral circuits in the live state. An advantageous effect is obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a bus line device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a device on which a bus line device is mounted.

FIG. 3 is a circuit diagram of a conventional bus line device.

FIG. 4 is a circuit diagram of an equivalent circuit of a peripheral circuit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Bus line package 10a Connector 11 Bus line 13 Driver circuit 14 Receiver circuit 15 Circuit package B Motherboard 19 Grounding resistance

Claims (1)

(57) [Scope of request for utility model registration] 1. A bus line device for exchanging signals between circuits via a bus line serving as a common transmission path, comprising: a plurality of drivers for receiving a signal from a peripheral circuit side and sending the signal to the bus line. Circuit and a connection provided between a control terminal of the driver circuit and ground.
And the earth resistance, said plurality of receiver circuits for feeding to the peripheral circuit side in response to a signal from the bus line, and a connector for connection to a mother board in which the peripheral circuit is connected is provided on the same foundation, the Power supply terminal connected to driver circuit and receiver circuit
And a ground terminal in the connector.
The resistor has one terminal connected to the control terminal of the driver circuit.
The other terminal is connected to the ground terminal,
Power and ground from the motherboard via the connector
A bus line device characterized by being supplied .