JPH05110618A - Digital line terminating equipment - Google Patents

Abstract

PURPOSE:To miniaturize a function block for holding an output voltage just after input power interruption and to increase profitability. CONSTITUTION:This equipment is provided with a clock generating circuit 5 frequency-dividing the output signal of a VCXO 4 and generating a reference clock, a frame transmission section 3 operated by receiving the reference clock and generating and sending a frame to inform an input power supply interruption signal outputted to an opposite device, and other signal processing circuit 6 operated through the reception of the reference clock. Then an inhibiting circuit 1 for blocking the input of the reference clock to the other processing circuit 6 by the entry of the input power supply interruption signal is interposed between the clock generating circuit 5 and the other processing circuit 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital line terminal device.

[0002]

2. Description of the Related Art FIG. 2 shows the configuration of a conventional digital line terminating device. In FIG. 2, the output of a voltage controlled crystal oscillator (hereinafter referred to as “VCXO”) 4 is divided by a clock generation circuit 5 to become a reference clock,
A frame transmission unit 3 that performs frame assembly to notify an opposite device (not shown) of an input power cutoff signal output when the power supply unit 2 is in an input power cutoff state, and another signal processing circuit 6 (this is here. , Only one is shown in the figure, but there are many cases in practice.)

[0003]

In the above-mentioned conventional digital line terminating device, both the frame transmitting section 3 for assembling the frame and the other signal processing circuit 6 for assembling the input power-off signal to the opposite device (not shown). Since the reference clock for constant operation is supplied to the device, the fixed time during the operation of the frame transmission unit 3 that notifies the other device of the input power cutoff information after the input power cutoff state is represented by the symbol in the figure. All other signal processing circuits within the device shown at 7 are operative. For this reason, the power consumed immediately after the input power is cut off is large, and it is difficult to downsize the functional block for the output voltage immediately after the input power cut off, that is, the output voltage holding circuit or the like that constitutes the power supply unit 2. There was an inconvenience.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital line terminating device capable of improving the disadvantages of the prior art and reducing the size and cost of the function block for holding the output voltage immediately after the input power is cut off. To provide.

[0005]

SUMMARY OF THE INVENTION A digital line terminating device of the present invention comprises a clock generating circuit for dividing an output signal of an oscillator to generate a reference clock, and an operation for receiving the reference clock to cut off input power from a power supply section. A frame transmission unit that generates and transmits a frame for notifying the opposite device of the input power-off signal that is output when the status becomes a state, and another signal processing circuit that operates by receiving the reference clock. And, between the clock generation circuit and the other signal processing circuit,
A prohibiting circuit is interposed to prevent the reference clock from being input to other signal processing circuits other than the frame transmitting unit by the input of the input power-off signal. With this configuration,
It is intended to achieve the above-mentioned purpose.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Here, the same components as those in the conventional example described above are denoted by the same reference numerals.

In the embodiment shown in FIG. 1, a clock generation circuit 5 which divides an output signal of a VCXO 4 as an oscillator to generate a reference clock, and a state in which an input power is cut off from a power supply section 1 by receiving the reference clock and operating. And a signal processing circuit 6 for receiving a reference clock and operating to generate a frame for notifying an opposite device of an input power-off signal output when There is. Then, the clock generation circuit 5 and the other signal processing circuit 6
A prohibiting circuit 1 for preventing the reference clock from being input to a signal processing circuit 6 other than the frame transmitting section 3 by the input of the input power-off signal is interposed between the and.

Next, the operation will be described. When the input power is switched from the input power-on state to the input power-off state, the power supply unit 2 detects this and outputs the input power-off signal to the frame transmission unit 3. At this time, since the reference clock output from the clock generation circuit 5 is supplied to the frame transmission unit 3,
The frame transmitter 3 operates to generate and transmit a frame for notifying the input power-off signal. As a result, the input power-off signal is notified to the opposite device (station side) not shown. Since the input power-off signal is also sent from the power supply unit 2 to the prohibition circuit 1, the prohibition circuit 1 blocks the reference clock from being input to the other signal processing circuits 6 by the input of the input power-off signal. Therefore, the reference clock is not input to the signal processing circuits 6 other than the frame transmitting unit 3, and the other signal processing circuits 6 stop operating.

As described above, according to this embodiment, since the signal processing circuits 6 other than the frame transmission unit 3 stop operating immediately after the input power is cut off, the power consumed immediately after the input power supply is cut off. As a result, the function block for holding the output voltage in the power supply unit 2 (such as the output voltage holding circuit forming the power supply unit 2) can be downsized and made economical.

Here, if the circuit forming the device, especially the other signal processing circuit 6 is a MOS gate logic circuit, the power consumption immediately after the input power is cut off can be further reduced.

[0011]

As described above, according to the present invention,
Immediately after the input power is turned off, the input of the reference clock for the operation to the signal processing circuits other than the frame transmission unit can be blocked by the function of the prohibition circuit, and thus the operation of the other signal processing circuits can be prevented. Since it can be stopped, it is possible to reduce the power consumed immediately after the power input is cut off, and it is possible to make the functional block for maintaining the output voltage in the power supply unit smaller and more economical, which in turn reduces the overall size of the device. -It is possible to provide an excellent digital line terminal device that has not been available in the past and that can be made economical.

In particular, the invention according to claim 2 has an effect that the power consumption immediately after the input power is cut off can be further reduced.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1 inhibit circuit 2 power supply section 3 frame transmission section 4 VCXO as oscillator 5 clock generation circuit 6 other signal processing circuit

Claims (2)

[Claims] 1. A clock generation circuit that divides an output signal of an oscillator to generate a reference clock, and an input power cutoff that is operated when receiving the reference clock and output from a power supply unit in an input power cutoff state. In a digital line terminating device comprising a frame transmitting unit for generating and transmitting a frame for notifying a signal to a counter device, and another signal processing circuit which operates by receiving the reference clock, the clock generating circuit and other signals A digital line terminating device, wherein a prohibiting circuit for preventing the reference clock from being input to the other signal processing circuit by the input of the input power-off signal is interposed between the processing circuit and the processing circuit. 2. The digital line terminating device according to claim 1, wherein the other signal processing circuit comprises a MOS gate logic circuit.