JPS6384338A - Power supply make/break control system - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention 1 (Field of Industrial Application) This invention relates to a power supply for equipment such as a modem that has a main circuit connected to external equipment such as a data terminal via an interface signal path. The present invention relates to a power on/off control method for controlling on/off.

(Prior Art) Generally, a data communication system is configured as shown in FIG. In the figure, 11 is a data terminal, 12 is a modem (M), 13 is a data network, and 14 is a computer. The modem 12 generally has a built-in power supply circuit, and is driven by the power from this power supply circuit. Note that some systems allow power to be supplied from the data terminal to the modem using an interface between the data terminal and the modem.
Even for modems used in such systems, the capacity is usually undefined when power is supplied from the data terminal, so it is common to have the above power supply circuit built-in and be driven by the power from the same power supply circuit. It is.

Now, the modem 12 is often installed apart from the data terminal 11, and therefore the power switch of the modem 12 is generally provided on the modem 12 side, independent of the power switch of the data terminal 11.

Therefore, the operator of the data terminal 11 has to perform an operation of turning on the power of the modem 12 at the same time as turning on the power of the data terminal 11, which is complicated.

On the other hand, it is possible to keep the modem 12 powered on all the time in order to omit the power-on operation of the modem 12, but it is also possible to power on the modem 12 even when the data terminal 11 is not powered on. Leaving it on is a waste of electricity.

(Problems to be Solved by the Invention) As mentioned above, in the past, attempting to eliminate the need to turn on the modem would result in wasted power, and attempting to save power would require turning on the modem. There was a problem.

This invention was made in view of the above circumstances, and its purpose is to eliminate the need to power on devices such as modems, and to
An object of the present invention is to provide a power on/off control system that can supply power only when necessary.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention provides a detection circuit that detects the power on/off state of a connected device based on a predetermined interface signal on an interface signal path, and A switch means for turning on/off the power is provided which operates according to the detection result of the circuit, and the turning on/off of the power is controlled by the above-mentioned interface signal.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of a modem 20 to which the present invention is applied. In the figure, 21 is the main circuit of the modem 20. The main circuit 21 is connected to an interface 30 with a data terminal (not shown) and an interface 40 with a data network (not shown). 22 is a power supply circuit for the modem 20 (the main circuit 21 therein); 23 is a switch that controls power on/off from the power supply circuit 22 to the main circuit 21; and 24 is a predetermined switch in the interface 30 that indicates the power on/off state of the data terminal. interface signal 31
This is a detection circuit that detects the power on/off state of the data terminal based on the state of , and controls the switch 23 on/off according to the detection result. In this embodiment, the detection circuit 24
is adapted to be driven by the power from the power supply circuit 22. Note that, for example, in a system in which the modem 20 and the data terminal are connected by an Ethernet cable (Ethernet is a registered trademark of Xerox Corporation in the United States), the interface signal 31 is the power signal of the bin 13 (the power on state of the data terminal). (10 levels) and the power return signal in bin 6 (1 level when the data terminal is powered on).

Next, the operation of the configuration shown in FIG. 1 will be explained. A detection circuit 24 within the modem 2° constantly monitors the interface signal 31 of the interface 30. When the interface signal 31 indicates that the data terminal is powered off,
The detection circuit 24 controls the switch 23 to turn off. In this case, power supply from the power supply circuit 22 to the main circuit 21 is prohibited (cut off).

If the power of the data terminal is turned on in this state, the interface signal 3 of the interface 3o
1 undergoes a state transition. In this case, the detection circuit 24 detects power-on of the data terminal by the state transition of the interface signal 31 to a predetermined level, and controls the switch 23 to turn on. This closes the switch 23, allowing power to be supplied from the power supply circuit 22 to the main circuit 21.

As described above, according to this embodiment, power is automatically supplied from the power supply circuit 22 built in the modem 20 to the main circuit 21 only while the data terminal is powered on. Therefore, it is not necessary to turn on/off the power switch of the modem 20, so that the modem 20 can be installed under the floor, on the ceiling, in the wall, etc. Further, since the power is turned on only when necessary (during the power-on period of the data terminal), it is possible to save power and extend the life of the main circuit 21.

FIG. 2 is a block diagram of a modem 50 showing another embodiment of the invention. Note that the same parts as in FIG. 1 are given the same reference numerals and detailed explanations are omitted.

In FIG. 2, 54 detects the power on/off state of the data terminal based on the state of the interface signal 31, and controls the switch 23 on/off according to the detection result.
This is a detection circuit similar to the detection circuit 24 shown in the figure. The difference between the detection circuit 54 in FIG. 2 and the detection circuit 246 in FIG. 1 is that the detection circuit 24 in FIG. The detection circuit 54 in FIG.
1 itself. Therefore, the second
In the illustrated configuration, the power consumption in the modem 50 is zero when the data terminal is not powered on. Then, when the power of the data terminal is turned on, the detection circuit 54 is driven by the interface signal 31, and the detection circuit 54 detects the switch 2 according to the interface signal 31.
3 is turned on, and power is supplied from the power supply circuit 22 to the main circuit 21. In FIG. 2, instead of the detection circuit 54, it is also possible to use a detection circuit that unconditionally turns on the switch 23 only during the period when it is driven by the interface signal 31.

The above description has been made regarding the case where it is implemented in a modem applied to a data communication system, but this invention can turn on the power of a connected device by monitoring the external interface signal, which is often noticeable if power is supplied only when the device is in use. /Applicable to all devices whose off state can be determined.

[Effects of the Invention] As detailed above, according to the present invention, the power on/off is controlled by the interface signal indicating the power on/off state of the connected device, so there is no need to turn on the power. Power can be supplied only when needed.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of a modem 20, 50 to which the present invention is applied.
...Modem, 21...Main circuit, 22...Power supply circuit, 23...Switch, 24.54...Detection circuit, 3
0.40...Interface, 31...Interface signal.

Claims (2)

[Claims] (1) In a device including a main circuit connected to an external device via an interface signal path, a detection circuit that detects a power on/off state of the device based on a predetermined interface signal on the interface signal path; A power-on/cut-off control system comprising a switch means that operates according to the detection result of the detection circuit, and is configured such that the drive power of the main circuit is turned on/off by the operation of the switch means. (2) The power on/off control system according to claim 1, wherein the detection circuit is driven by the predetermined interface signal.