JPS62260256A - Interface switching circuit - Google Patents

Abstract

PURPOSE:To attain the automatic switch of connection among interfaces with small power consumption by using the array of analog switches using semiconductors and at the same time obtaining the drive voltage from the signals lines of interfaces. CONSTITUTION:The signals (a) and (b) showing whether devices A and B are set or not in communication active modes are sent to a control circuit 2 among those signals transmitted from interfaces 1A and 1B. Then the signals S and the inverse of S are produced and transmitted to control ON/OFF of switch circuits 4A and 4B, i.e., arrays of analog switches of low power consumption forming a CMOS integrated circuit. When the positive or negative voltage emerges at a signal line, a diode circuit 3A or 3C is conducted to charge a capacitor C1 or C2. Then the produced positive and negative voltages V+ and V- are used to drive switches. When the signal S or the inverse of S is set at the high level of voltage, the circuit 4A or 4B is simultaneously turned on.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interface switching circuit, and more particularly to an interface switching circuit for switching a combination of interconnections between a data terminal device and a data line termination device.

[Conventional technology]

Conventionally, when multiple data terminal devices or data line termination devices are installed, a manual switch or relay circuit is used as an interface switching circuit to establish one-to-one interconnection between the two devices. is used. Since the interface between both devices has multiple signal lines, conventional interface switching circuits either use a multi-contact multi-circuit switch to switch connections manually, or use multiple relays. The constructed relay circuit is used to apply an electrical signal for switching instructions to switch the connection.

[Problem that the invention seeks to solve]

In the conventional interface switching circuit described above, if a switch is used, connection switching can only be done manually, which makes the operation complicated, and if a relay circuit is used, automatic switching is possible, but the relay drive is difficult. Since a power supply with a considerably large power supply capacity is required for the purpose of use, there are problems in that an increase in power consumption and an increase in the size of the power supply section are unavoidable.

An object of the present invention is to provide an interface switching circuit that solves the above-mentioned problems and automatically switches interface connections with low power consumption.

[Means for solving problems]

The circuit of the present invention is connected between the interfaces of a plurality of first devices and the interface of one second device, respectively, in the middle of a group of signal lines, and is capable of switching on/off the group of signal lines. a plurality of switch circuits each having a semiconductor switch group for performing the above-mentioned signal line group; a power supply extraction circuit for extracting the drive voltage of the semiconductor switch group from a predetermined location of the signal line group; Generates and sends a control signal to select and turn on only one of the plurality of switch circuits in response to the received electric signal indicating the presence or absence of an operation instruction for each of the first devices. control circuit.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The figure exemplifies a case where either one of the data terminal device and the data line termination device is two (devices A and B), and the other one is one (device C). It is easy to expand and apply the system to three or more devices.

In the figure, interfaces IA and IB are terminal groups to which signal lines are connected at the interfaces of devices A and B, respectively, and interface IC is a group of terminals connecting signal lines at the interfaces of devices A and B, respectively.
This is a group of terminals for the interface. interface IA
The signal line group having one end connected to each of IBK and IBK is connected to the other end of the interface ICK via switch circuits 4A and 4B, respectively. Interface I
The signal line group for passing the output signal of A (or IB) is connected between the switch circuit 4A (or 4B),
It is branch-connected to the diode circuit 3A (or 3B). Further, the signal line group through which the output signal of the interface IC passes is branch-connected to the diode circuit 3C. The positive voltage output terminals of the diode circuit 3 or 3C are both connected to one end of the capacitor C1, and the negative voltage output terminal H is connected to one end of the capacitor C2. Among the sending signals, a signal a indicating whether the device is in the communication operation mode and a signal indicating whether or not the device B is in the communication operation mode are transmitted to the control circuit 2.
sent to. The control circuit 2 generates and sends out signals S and S for respectively controlling the on/off of the switch circuits 4 and 4B in response to the signals a and b, as will be described later.

The diode circuit 3 or 3C consists of an array of diodes Dl connected in the forward direction from each signal line to the positive voltage output terminal (+), and an array of diodes D2 connected in the reverse direction from each signal line to the negative voltage output terminal H. It is equipped with. When a positive voltage (or negative voltage) appears on the signal line, the diode Ih (or D2) connected thereto becomes conductive and charges the capacitor C1 (or C2). The positive and negative voltages + and V- generated by charging the capacitors C1 and C2, respectively, are given to the switch circuits 4 and 4BK as voltages for driving switches (connection diagrams are omitted).Switch circuits 4A and 4B
For example, there are 7 arrays of low power consumption analog switches constructed of 8 CMO integrated circuits, and each analog switch is connected to a signal line. Signals S and S
, when one is at a high level voltage vH, the other is at a low level voltage v.

The analog switches of the switch circuit 4A (or 4B) all turn on when the signal S (or S) becomes VH, and turn off all at once when the signal S becomes VL, for example.

FIG. 2 is a circuit diagram showing an example of the configuration of the control circuit 2 in this embodiment. Signals a and b are connected to devices A and B, respectively.
When is in communication operation mode, it is V, and when it is no longer in communication operation mode, it is VL. Signal a is exclusive OR (
EX-OIL) is sent to the gate 20, and the logical sum (
0 几) is being sent to gate 22. Signal Suha EX-O
R, sent to gate 20. The output signal of EX-OR is
After passing through the inverter 21, it is sent to the gate 22.The output signal of the OIL gate 22 is sent out as the signal S via the switch SW for automatic and manual switching, and the signal S is sent through the inverter 23. Therefore, during automatic switching, that is, when switch SW is OR
When connected to gate 22, signal a is VH
If so, the signal S is VHK regardless of the level of the signal S.
As a result, the switch circuit 4A is turned on, and the switch circuit 4B is turned off. Only when the signal a is VL and the signal A is VH, the signal S becomes V, and the switch circuit 4B is turned on. That is, during automatic switching, switching control is performed to give priority to device-based communication operations. Note that the high level voltage ■H or the low level voltage ■L is applied to the other switching terminals of the switch SW so that switching control can be performed manually.

In this way, in this embodiment, connection switching is performed using an array of analog switches using low power consumption semiconductors, and the drive voltage for the analog switches is obtained from the signal line of the interface. This avoids an increase in the required power consumption and an increase in the size of the power supply section.

Furthermore, the connection switching is controlled by giving a signal indicating the presence or absence of a communication operation instruction from the side where multiple devices are installed.
Connection switching can be performed automatically.

〔Effect of the invention〕

As described above, the present invention has the advantage that it is possible to realize an interface switching circuit that automatically switches interface connections with low power consumption.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 are a block diagram and a circuit diagram, respectively, showing an embodiment of the present invention. IA, IB, IC...Interface, 2.
...Control circuit, 3A, 3B, 3C...
Diode circuit, 4A, 4B, 4C...Switch circuit, C1, C2...Capacitor, DI
r D2...Diode, 20...Exclusive OR (EX-0) gate, 21, 23...
... Inverter, 22 ... Logical OR (0 几) gate. $1 Figure

Claims (1)

[Claims] Semiconductor switches each connected in the middle of a group of signal lines connecting each interface of a plurality of first devices and an interface of one second device and for switching on/off the group of signal lines. a plurality of switch circuits having a plurality of switch circuits, a power supply extraction circuit for extracting the drive voltage of the semiconductor switch group from a predetermined location of the signal line group; a control circuit that generates and sends a control signal for selecting and turning on only one of the plurality of switch circuits in response to an electrical signal indicating the presence or absence of an operation instruction for the first device; An interface switching circuit characterized by: