JPH03286668A - Power receiving circuit for phantom feeding - Google Patents

Abstract

PURPOSE:To save useless power consumption by interrupting phantom feeding to a DC/DC converter in the standby state of an ISDN terminal equipment and activating the phantom feeding to the DC/DC converter in the active state. CONSTITUTION:When an ISDN terminal equipment such as a telephone set is in the standby state, since a signal from an ISDN line 21 is not received, a detection signal S1 of a reception signal detection circuit 11 is not outputted and a relay 12 is deenergized. On the other hand, since the telephone set is hooked on, a switch 13 is opened and the feeding to a DC/DC converter 14 is stopped. Thus, when the telephone set is in the standby state, the relay 12 and the switch 13 are opened and the feeding to the DC/DC converter 14 is interrupted and when the telephone set is in the operating state, the switch 13 or the relay 12 are closed and the feeding to the DC/DC converter 14 is implemented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a phantom power receiving circuit used in a 15DN terminal.

BACKGROUND ART 15DN terminals For example, 15DN telephones receive phantom (telegraph) power from a station through a line as an operating power supply, and when in a standby state without making or receiving calls or making calls, the CP
Low power consumption was achieved by setting the U and I interfaces to idle mode (low power consumption mode).

Problems to be Solved by the Invention However, in conventional telephones such as 2, after detecting the standby state, a new process is required for both hardware and software to shift the CPU and 1 interface to idle mode. CI)
The problem is that the power consumed by the U and I interfaces and the DC/DCC/type controllers that convert the power supply voltage into the operating voltage of the telephone reaches tens of milliwatts, increasing the power supply burden on the 15DN line side. There was a point.

The present invention solves such conventional problems, and provides a power receiving circuit for phantom power feeding in a 15DN terminal that enables extremely effective reduction in power consumption by adding simple hardware. The purpose is to

Means for Solving the Problems In order to achieve the above object, the present invention turns off the power supply to the DC and /'DC converters when the telephone is on-hook and there is no received signal in a standby state in the +SDN terminal. Switching means I SDN line and DC/DC
It is inserted between the converters.

Therefore, according to the present invention, the phantom power supply to the DC/DC converter is turned off in the standby state of the 15DN@ terminal, and the phantom power supply to the DC/DC converter is turned off in the operating state such as outgoing, incoming, or talking states.
/Turn on the phantom power supply to the DC converter,
Saves tens of mW of wasted power consumption in standby mode,
■Power can be supplied from the SDN line only in the operating state, making it possible to reduce power consumption.

Embodiment FIG. 1 shows a phantom power receiving circuit according to an embodiment of the present invention. In Figure 1, 11 has a signal amplitude of 0,
This is a received signal detection circuit that detects a received signal of 75V (potential difference of signal line B with respect to reference point A is 0.75V) and outputs a detection signal S1 when the received signal is detected. This received signal detection circuit 11 has a very high human impedance so as not to affect the network. 12 is a relay that receives the detection signal S1 of the received signal detection circuit 11 and turns on/off the phantom power supply.

Reference numeral 13 denotes a switch that moves with the hook switch so that it is turned off when the hook switch is on, and turned on when the hook switch is off. 14 is a DC/DC converter that converts the power supply voltage of 40V to +5V. 21 is a 15DN line, and power is supplied superimposed on a signal from a DSU (network terminal unit) 22. 23 is an 8-pin modular that is an interface connector between the terminal and the line, 24 is a pulse transformer for extracting only the signal component of the line, and 25 is a receiver/driver for transmitting and receiving signals.

There are two types of relays that can be used as the relay 12: a relay that uses the detection signal itself as power for the relay, and a latching relay that uses the detection signal as an on/off trigger.

The former type of relay can reduce power consumption because no current flows through the relay when there is no received signal, but current is passed through the relay and the relay is turned on when there is a received signal, which consumes current.

The latter relay consumes power only when switching on/off, resulting in extremely low power consumption.
This is most suitable for this embodiment.

Next, the operation of the embodiment will be explained with reference to FIGS. 2 and 3. When the 15DN terminal, for example, a telephone, is in a standby state, there is no signal from the 15DN line, so the detection signal S1 of the received signal detection circuit 11 is not output, and the relay 12 is turned off. On the other hand, since the telephone is in an on-hook state, the switch 13 is also off, and power supply to the DC/DC converter 14 is stopped (standby state in Figures 2 and 3).
.

Next, when a call is to be made, since the telephone is in an off-hook state, the switch 13 is turned on, power is supplied to the DC/DC converter 14, and the telephone becomes operational (the call state in FIG. 2).

Additionally, when there is an incoming call, the detection signal S1 of the received signal detection circuit 11 is output, the relay 12 is turned on, and the D
C,'DC Power is supplied to the C converter 14, and the telephone becomes operational (call receiving state in FIG. 3).

2, according to the embodiment, when the telephone is in the standby state, both the relay 12 and the switch 13 are turned off and the DC
,' When the power supply to the DC converter 14 is cut off and the telephone becomes operational, the switch 13 or relay 12 is turned on and power is supplied to the DC/DC converter 14, thereby reducing wasted power consumption. Therefore, it is possible to effectively reduce power consumption.

As described in detail, according to the present invention, when a 15DN terminal enters a standby state, this is detected and the power supply is stopped, thereby reducing the power supply capacity of the 15DN line. It has the excellent effect of being able to significantly reduce the amount of energy required, and allowing the system to operate with extremely low power consumption.

[Brief explanation of drawings]

FIG. 1 is a phantom power supply circuit diagram according to an embodiment of the present invention, FIG. 2 is a timing chart when a call is made from a standby state in the same embodiment, and FIG. 3 is a diagram when an incoming call is received in a standby state in the same embodiment. This is a timing chart when 11... Received signal detection circuit, 12... Relay 13
...Switch, 14...DC/DC converter, 2
1...15 DN line, 22...DSU (network terminal unit), 23...8 pin module, 24...pulse transformer, 25...receiver/driver.

Claims (1)

[Claims] means for turning on/off the phantom power supply to the DC/DC converter depending on the presence or absence of the received signal; and means for turning on/off the phantom power supply to the DC/DC converter in conjunction with a hook switch; 1. A power receiving circuit for phantom power feeding, characterized in that when the hook switch is in an on state, power feeding to the DC/DC converter is turned off.