JPS63109518A - Duplicated clock supply circuit - Google Patents

Abstract

PURPOSE:To obtain an inexpensive duplicated clock with high reliability and quality by providing a detector detecting the occurrence of intermission of an active clock and a switch using a control signal from the detector so as to switch the active clock outputted also to a standby output terminal into the standby clock. CONSTITUTION:A clock generated from an active clock generator 1 is sent from an output terminal 5 and also supplied to a detector 3 as a branched output. The detector 3 detect and decides the presence of the clock from the active clock generator 1 to activate a switch 4. The switch 4 is thrown to the position shown in solid lines in the presence of the clock from the active clock generator 1, and the clock from the active clock generator 1 is sent also to the standby output terminal 6. If the clock intermission from the active clock generator 1 is detected, the detector 3 supplies the control signal (d) to throw the switch 4 to the position shown in broken lines so as to allow the switch 4 to switch the clock from the standby clock generator 2 to the standby output terminal 6.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a duplex clock supply circuit, and particularly to a dual clock supply circuit.
'This invention relates to a duplex clock supply circuit that sends out a clock having the same phase as the backup clock.

[Conventional technology]

Conventionally, in this type of duplex clock supply circuit, in order to match the phases of clocks on the working side and the standby side, the standby side has used a phase synchronization circuit consisting of a voltage-controlled oscillator and a single phase comparator.

FIG. 2 is a block diagram showing an example of a conventional duplex clock supply circuit.

In the figure, the conventional duplex clock supply circuit consists of a working side independent oscillation type clock generator 7, a protection side dependent synchronous clock generator 8, a phase comparator, and working side and protection side output terminals 10 and 11. It is configured.

Next, the operation of this example will be explained.

A clock generated from the working side independent oscillation type clock generator 7 is sent to the working side output terminal 10 and simultaneously sent to the phase comparator 9. The phase comparator 9 includes a working side independent oscillation type clock generator 7 and a protection side dependent synchronous type clock generator 8.
By receiving the output clock from and detecting the phase difference between these clocks, a control voltage V for phase synchronization to the standby slave synchronization type clock generator 8 is generated. Phase comparator 9
The protection side slave synchronization type clock generator 8 which receives the phase synchronization control voltage ■ from the active side independent oscillation type clock generator 7 generates a clock that is phase synchronized with the active side independent oscillation type clock generator 7, and sends this clock to the protection side output terminal 11. do.

[Problem that the invention seeks to solve]

In the conventional duplex clock supply circuit described above, the clock generator on the working side and the clock generator on the protection side are independent, so phase comparison is always required to synchronize the clock on the protection side with the clock on the working side. This method requires a synchronization control circuit in the clock generator and the standby clock generator, and the overall circuit configuration is expensive and complicated, resulting in a deterioration in the reliability and quality of the clock.

[Means for solving problems]

The duplex clock supply circuit of the present invention detects the generator of the working clock in the duplex clock supply circuit having a working clock generator that generates a working clock and a protection clock generator that generates a protection clock. and a switch that switches the working clock, which is also output to the backup output terminal, to the backup clock in response to a control signal from the detector.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the same figure, the present embodiment includes a detector 3 that detects disconnection of the output clock from the working and standby clock generators 1 and 2 and the working clock generator 1 and outputs a control signal d; It is composed of a switching device 4 controlled by a switch 4, and output terminals 5 and 6 on the active side and standby side.

Next, the operation of this embodiment will be explained.

The clock generated by the active clock generator 1 is sent out from the output terminal 5 and at the same time is sent out to the detector 3 as a branch output. The detector 3 detects and determines the presence or absence of a clock from the active clock generator 1 as an input, and operates the switch 4.

If there is a clock from the working side clock generator 1,
The switch 4 is in the solid line state as shown in FIG. 1, and the clock from the working clock generator 1 is also sent to the standby output terminal 6.

If a clock disconnection from the working clock generator 1 is detected, the detector 3 switches to send the clock from the protection clock generator 2 to the protection output terminal 6 by sending the control signal d. The device 4 is operated as shown by the broken line.

〔Effect of the invention〕

As explained above, the present invention does not require an expensive and complicated slave synchronous clock generator for synchronization, which is used in conventional duplex clock supply circuits, for the backup side clock generator. , a phase comparator that can use the same clock generator as the working side clock generator, and by using a detector that detects the presence or absence of the clock from the working side clock generator, the quality of the standby side clock will deteriorate. Since this method does not require a dual clock, it is possible to supply a duplex clock with higher reliability and quality at a lower cost than before.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional duplex clock supply circuit. DESCRIPTION OF SYMBOLS 1... Working side clock generator, 2... Standby side clock generator, 3... Detector, 4... Switching device, 5...
Working side output terminal, 6... Standby side output terminal, 7... Working side independent oscillation type clock generator, 8... Standby side dependent synchronous type clock generator, 9... Phase comparator, 10.・・・
Working side output terminal, 11... Standby side output terminal.

Claims (1)

[Claims] In a duplex clock supply circuit having a working side clock generator that generates a working side clock and a protection side clock generator that generates a protection side clock, a detector for detecting generation interruption of the working side clock; a switch for switching the working clock, which is also output to a backup output terminal, to the backup clock according to a control signal of the dual clock supply circuit.