JP3346318B2 - Package switching circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package switching circuit which performs switching for selecting a normal one of circuit packages having a duplex configuration and does not cause unnecessary switching.

[0002]

2. Description of the Related Art In a telephone transmission device or the like, it is customary to secure a desired MTBF by selecting and using one of the two circuit packages to improve reliability. FIG. 2 shows a conventional package switching circuit. The switching package 21 has a selection circuit 23 for selecting one of the packages 26 and 27 of the duplex configuration, and a switching control signal 205 from the switching control package 22.
Make that choice. The switching control package 22 includes:
Two NANDs connected so that the failure signal 202 from one package 26 is input to the set side and the failure information 204 from the other package 27 is input to the reset side
A switching control signal is generated by a flip-flop including the gates 24 and 25 and output to the switching package 21.

[0003]

However, in the above-described conventional package switching circuit, unnecessary signal switching is performed due to insertion / removal of the switching control package 22, thereby causing an error in a main signal processed in the apparatus. There was a problem that the problem described above occurs.

The present invention has been made in view of such a background, and provides a package switching circuit that performs switching to select a normal one of circuit packages having a duplex configuration and that does not cause unnecessary switching. The purpose is to provide.

[0005]

According to the present invention, there is provided a first embodiment in which one of the packages having a duplex configuration is selected by a selection signal.
And a switching package having a latch circuit for supplying a selection signal to the first selection circuit in response to a reset signal from the switching control package or a switching control signal, and a reset signal for a predetermined time when power is turned on. A switching control package having a power-on reset circuit to send, a setting signal to send a switching control signal to the switching package in accordance with the selection signal from the switching package, failure information from each of the duplexed packages, and the reset signal; Provided is a package switching circuit characterized by comprising:

Further, the present invention is characterized in that the setting means selects an inverted signal of the selection signal from the switching package by an inverter when a reset signal is sent out, and otherwise selects one of the duplicated packages. A second selection circuit for selecting the failure information of the package, and selecting the selection signal from the switching package when the reset signal is transmitted, and otherwise, selecting the failure information from the other of the duplicated packages. A third selection circuit to select;
2. The package switching circuit according to claim 1, further comprising a flip-flop circuit for inputting an output of said second selection circuit to a set side and inputting an output of said third selection circuit to a reset side. .

In the present invention, the duplex package, the switching package, and the switching control package are configured as a single device, and the switching control package is disposed so as to be freely inserted into and removed from the device. 1
Or, a package switching circuit according to item 2 is provided.

As described in the claims, the package switching circuit of the present invention uses a first selection circuit for selecting one of the packages having a duplex configuration by a selection signal, and a reset signal and a switching control signal from the switching control package. A switching package having a latch circuit for supplying a selection signal to the selection circuit; a power-on reset circuit for outputting a reset signal for a predetermined time after power-on; and a switching package from the switching package when the reset signal is output. A second selection circuit that selects an inverted signal of the selection signal by the inverter, and otherwise selects the failure information of one package, and selects a selection signal from the switching package when the reset signal is output, Otherwise, a third selection circuit for selecting the failure information of the other package, and a second selection circuit The output of the road on the set side, and the switching control package having setting means having a flip-flop circuit for inputting the output of the third selection circuit in the reset side.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a package switching circuit according to an embodiment of the present invention. Thus the first selection circuit 4 selects one of the duplex package 13. When the reset signal 108 from the switching control package 3 is not transmitted, the latch circuit 5 latches the switching control signal 107 from the switching control package 3 and sends the selection signal 10 to the first selection circuit 4.
6 is output, and the selection signal 106 is not updated while the reset signal 108 is being transmitted.

On the other hand, the power-on reset circuit 7 of the switching control package 3 outputs a reset signal
08 is output. The second selection circuit 9 selects the inverted signal 109 of the selection signal 106 from the switching package 2 by the inverter 8 when the reset signal 108 is output, and otherwise selects and outputs the failure information 102.

In the third selection circuit 10, the reset signal 1
When 08 is output, the selection signal 106 from the switching package 2 is selected. Otherwise, the failure information 104 is selected and output. The switching control signal 107 is created by a flip-flop circuit composed of NAND gates 11 and 12 that inputs the output 110 of the second selection circuit 9 to the set side and the output 111 of the third selection circuit 10 to the reset side.

The operation of one embodiment of the present invention has been described in detail with reference to the drawings. However, the present invention is not limited to this embodiment, and a design change or the like may be made without departing from the gist of the present invention. The present invention is also included in the present invention.

[0013]

As described above, in the package switching circuit of the present invention, when the switching control package is inserted, the switching control signal is generated by the switching package selection signal. Unnecessary switching can be prevented by performing an operation of not updating the selection signal until the switching control package normally starts up by the reset signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a package switching circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional package switching circuit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 package switching circuit 2 switching package 3 switching control package 4 first selection circuit 5 latch circuit 6 setting means 7 power-on reset circuit 8 inverter 9 second selection circuit 10 third Selection circuits 11, 12 NAND gates 13, 14 Duplex package 21 Switching package 22 Switching control package 23 Selection circuit 24, 25 NAND gate 26, 27 Duplex package

Claims (1)

(57) [Claims] 1. A power-on reset for transmitting a reset signal.
Switching control package with a switching circuit and a redundant configuration
Cut the two packages and the two packages
Switching package with switching package
There are, the switching package, said switching system when said reset signal is not sent
Latch the switching control signal from the
Updates the output selection signal while the reset signal is being sent.
A latch circuit that does not operate, and the two circuits based on the selection signal from the latch circuit.
The first selection to select one of the packages
And the switching control package, when the reset signal is transmitted , the switching control package.
Selecting an inverted signal of the selection signal from the package,
Otherwise, failure from one of the two packages
A second selection circuit for selecting and outputting information; and a switching circuit when the reset signal is transmitted.
Select the selection signal from the package, otherwise
Select failure information from the other of the two packages
A third selection circuit for outputting, and an output of the second selection circuit on the set side, the third selection circuit
The output of the circuit is set to the reset side, and the second and third
A switch for outputting the switching control signal based on the output of the selection circuit.
Package, characterized in that it comprises a flip-flop circuit
Page switching circuit.