JP2004032634A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply technique by which a risk of breakage etc., of equipment can be avoided when power supply side network equipment corresponding to a power supply system which supplies electric power through one Ethernet cable is connected to another equipment not corresponding to the system through the Ethernet cable. <P>SOLUTION: A power supply device 1 is provided with an auxiliary power supply means C which can supply low-voltage auxiliary power, the maximum output current limited to a prescribed current value or smaller, to the Ethernet cable, a main power supply means B which can supply main power required by another Ethernet equipment connected through the Ethernet cable, and control means D and E which control the main power supply means B so as to connect the means B to the Ethernet cable only when the value of the current flowing through the Ethernet cable falls within a prescribed range by connecting the auxiliary power supply means C to the Ethernet cable. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a system for connecting both a network signal and a power supply with a single computer network cable.
[0002]
[Prior art]
Conventionally, a method of connecting both a network signal and a power supply with one computer network cable may be adopted.
For example, when wiring between a main network device having a built-in power supply device such as a personal computer and a hub and a sub-network device having no built-in power supply device such as an access point device for a wireless LAN, Usually, in addition to the computer network cable connecting between the main network device and the sub network device, it is necessary to wire a power cable for supplying power to the sub network device.
However, if a method of connecting both a network signal and a power supply with a single computer network cable is adopted, the power required by the sub network device can be reduced by using the computer network cable for data communication. It becomes possible to supply from the device to the secondary network device. Therefore, since it is not necessary to wire a power cable for supplying power to the sub-network device, wiring work around the sub-network device is simplified.
[0003]
[Problems to be solved by the invention]
In such a system in which both a network signal and a power supply are connected by a single computer network cable, the power is supplied via a thin computer network cable having a small voltage drop, and the power supply side (mainly On the network device side), a voltage of several tens of volts may be applied to the computer network cable.
On the other hand, in a general network device that does not support a method of receiving power supply via a computer network cable, the core wire of the computer network cable has a terminating resistance of about 100 ohms in the case of Ethernet (registered trademark), for example. If a computer network cable to which power is applied is accidentally connected to these unsupported devices, the terminating resistor may be burned and a fire may occur. There was a danger of an accident.
[0004]
Accordingly, the present invention relates to a method of connecting a power supply side (main network device side) network device that supports a method of supplying power with a single computer network cable and an unsupported device to a computer network. An object of the present invention is to provide a power supply technology capable of avoiding the above-mentioned danger when connected by a cable.
[0005]
[Means for Solving the Problems]
In the power supply device according to the present invention, in the power supply device configured to be able to supply power to another network device connected via one computer network cable, the computer network cable has a maximum capacity. A sub-power supply unit capable of supplying a low-voltage sub-power whose output current is limited to a predetermined current value or less, and a main power required by another network device connected via the computer network cable. Main power supply means, and the sub power supply means are connected to the computer network cable, and the main power supply means is connected only when a current flowing through the computer network cable is within a predetermined range. Control means for controlling connection to the computer network cable With.
[0006]
According to the above configuration, by connecting the sub-power supply unit to the computer network cable by the control unit, when the value of the current flowing through the computer network cable is within a predetermined range, the other connected device is connected to the computer network cable. It can be determined that the network device is configured to receive power supply via the computer network cable. Therefore, in that case, the main power supply means is connected to the computer network cable to supply power.
When the value of the current flowing through the computer network cable is not within a predetermined range, another network device is not connected, or the other connected network device supplies power via the computer network cable. It can be determined that it is not configured to receive Therefore, in those cases, the main power supply means is not connected.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a power supply device according to the present invention will be described in detail with reference to the drawings showing the embodiments.
[0008]
Reference numeral 1 denotes a power supply device according to the embodiment, which includes a normal network device 2 and a computer network cable 42 which are not configured to supply power via a computer network cable (specifically, an Ethernet (registered trademark) cable). It has a connector A connected thereto, and a connector F connected to a network device 3 configured to receive power supply via a computer network cable and a computer network cable 43.
These connectors A and F will be described below as connectors for connecting, for example, an Ethernet (registered trademark) cable compatible with 100BASE-TX compliant with IEEE 802.3u.
[0009]
The network signal connection terminals A1, A2, A3, and A6 of the connector A are directly connected to the network signal connection terminals F1, F2, F3, and F6 of the connector F via a twisted pair cable.
The connection terminals A4, A5, A7 and A8 of the connector A not used for transmitting network signals are terminated by terminating resistors.
The connection terminals F4 and F5 of the connector F that are not used for transmitting network signals are connected to a main power supply unit B and a sub power supply unit C described later, and the connection terminals F7 and F8 are grounded.
[0010]
The main power supply unit B generates 48 volts as a main power supply from DC 12 volts supplied from an external power supply circuit, performs on / off control by a switching circuit E1 using transistors, and connects the connection terminal via a diode E2. It is configured to output to F4 and F5. The switching circuit E1 including the transistors is controlled by a control signal described later.
The auxiliary power supply unit C is configured to generate 3.3 volts as an auxiliary power supply from 12 volts DC supplied from an external power supply circuit and output it to the connection terminals F4 and F5 via a diode E3. ing.
[0011]
The current detection unit D includes a main current detection unit D1 for detecting a current value output via the main power supply unit B, and a sub-current detection unit for detecting a current value output via the sub-power supply unit C. The part D2 and the current value detected by these are compared with a predetermined lower limit value and an upper limit value, and whether the current value is less than the lower limit value (state {circle around (1)}) or not less than the lower limit value and less than the upper limit value ( State (2)) and a window comparator section D3 for monitoring whether or not the upper limit value is exceeded (state (3)). The following description is based on the assumption that the lower limit is set to 3 mA and the upper limit is set to 15 mA.
[0012]
In the case of the state (1), it can be determined that no network device is connected to the connector F.
In the case of the state (2), it can be determined that the connector F is connected to a network device configured to be supplied with power via a computer network cable.
In the case of the state (3), it can be determined that the connector F is connected to a network device that is not configured to be supplied with power via a computer network cable.
[0013]
The operation control unit E includes a control circuit E4 to which a comparison result signal output from the window comparator unit D3 is input and outputs a control signal to the switching circuit E1 by the transistor based on the comparison result signal.
In the control circuit E4 of the operation control unit E, based on the comparison result signal, if the value is less than the lower limit, the state is determined to be state (1). It is determined as 2), and if it is not less than the upper limit, it is determined as state 3).
For example, if the terminating resistor is 100 ohms and the auxiliary voltage is 3.3 volts, then when network equipment not configured to receive power via a computer network cable is connected, Since a current value of 33 mA is detected, it is determined that the current value is equal to or larger than the upper limit value.
[0014]
Then, the control circuit E4 of the operation control unit E outputs a control signal for turning off the switching circuit E1 by the transistor when the state is determined to be state (1), and when the state is determined to be state (2). Outputs a control signal to turn on the switching circuit E1 by the transistor, and outputs a control signal to turn off the switching circuit E1 by the transistor when it is determined to be in the state (3).
In the initial state of the operation control unit E, the switching circuit E1 including the transistor is turned off by the control signal.
[0015]
Then, when the switching circuit E1 by the transistor is turned off, the main power supply unit B is disconnected from the connection terminals F4 and F5 of the connector F. At this time, the output of the sub power supply unit C is connected to the connection terminals F4 and F5 of the connector F because the diode E3 is in the forward direction.
Then, when the switching circuit E1 by the transistor is turned on, the main power supply section B is connected to the connection terminals F4 and F5 of the connector F and applies 48 volts. At this time, since the diode E3 connected to the sub power supply unit C is in the opposite direction, 48 volts does not flow back to the sub power supply unit C.
The operation control section E includes a switching circuit E1 using the transistors, diodes E2 and E3, and a control circuit E4.
The current detection unit D and the operation control unit E constitute control means described in the claims.
[0016]
The operation will be described based on the above configuration.
First, in an initial state, since the switching circuit E1 of the transistor is off, the output of the main power supply unit B is not supplied to the connector F, and the output of the sub power supply unit C is supplied to the connector F. Supplied.
Therefore, when a network device is not connected to the connector F via a computer network cable, the current value detected by the sub-current detection unit D2 is less than the lower limit value, and the state is (1). Is determined.
Then, in this state, the monitoring of the current value by the sub-current detector D2 is continued.
[0017]
Next, when the network device 3 is connected to the connector F via a computer network cable 43, and the network device 3 is a network device compatible with a method of supplying power via a computer network cable, The current value detected by the sub-current detection unit D2 is equal to or more than the lower limit value and less than the upper limit value, and it is determined that the state is (2).
Accordingly, a control signal for turning on the switching circuit E1 by the transistor is output from the control circuit E4, the switching circuit E1 by the transistor is turned on, and the output of the main power supply unit B is supplied to the connector F. . Therefore, power is supplied to the network device 3 connected to the connector F via the computer network cable 43.
[0018]
In this state, the monitoring of the current value by the main current detection unit D1 is continued. If the current value is, for example, 10 mA or more and less than 200 mA, the corresponding device is operating normally (state (4)). If the current value is less than 10 mA, the connection is disconnected (state (5)). If so, it is determined that there is an abnormality such as a short circuit (state (6)).
In the states (5) and (6) other than the state (4), the output of the main power supply (48 volts) is turned off and the current value in the state where the sub power supply (3.3 volts) is applied. Return to monitoring state.
As described above, when it is determined that the state is the state (5) or the state (6), a control signal for turning off the switching circuit E1 by the transistor is immediately output from the control circuit E4. When turned off, the output of the main power supply section B is disconnected from the connector F.
Note that a window comparator section for the main current detection section D1 and a window comparator section for the sub-current detection section D2 may be separately provided.
[0019]
As described above, since the state and type of the network device connected to the connector F are monitored and determined based on the current value, it is possible to automatically control the supply / non-supply of power according to the connected network device. Can be.
Therefore, without using a connector having a special shape or a cable for a computer network, it is possible to prevent a risk that the wrong device is connected and the device is damaged.
[0020]
In addition, the current value is constantly monitored, and when the current value exceeds the upper limit value, the power source is automatically switched to the sub power source. Therefore, a protection device against a short circuit of the output of the main power supply unit B becomes unnecessary.
[0021]
The voltages of the main power supply and the sub power supply, and the upper limit value and the lower limit value can be set to various values according to conditions of a computer network cable, connected network devices, and the like.
As the connector and the cable for the computer network, connectors and cables of various standards can be used as long as there are extra cores other than the core for transmitting the network signal.
Further, the power supply device 1 may be incorporated in a conventional network device having only a function of transmitting a network signal via a computer network cable.
[0022]
【The invention's effect】
As described above, according to the power supply device of the present invention, the network device on the power supply side corresponding to the method of supplying power with one computer network cable and the above-described method are supported. When the power-supplied-side network device is connected by a computer network cable, power can be supplied to the power-supplied-side network device via the computer network cable, and one power supply can be performed. If a network device on the power supply side that supports power supply using a computer network cable is connected to a device that does not support the above method using a computer network cable, damage to the device, etc. The effect that the danger of can be avoided can be obtained.
[0023]
In addition, the above-described effects can be obtained without using a connector having a special standard or shape or a cable for a computer network.
Therefore, since a commercially available connector or a cable for a computer network can be used as it is, the cost required for installation can be reduced.
[0024]
Also, even if you touch the terminals of the computer network cable and connectors that are exposed because the devices and cables are not connected, only a low voltage is applied, so there is no danger of electric shock or the like, and it is safe. .
Further, an effect is obtained that the description of the precautions in the instruction manual or the like attached to the device or the apparatus can be minimized.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of a power supply device according to the present invention.
[Explanation of symbols]
1 power supply device 2 network equipment (not compatible with power supply method with computer network cable)
3 Network equipment (Compatible with power supply method using computer network cable)
42 Computer Network Cable 43 Computer Network Cable A Connector B Main Power Supply Unit, Main Power Supply Unit C Sub Power Supply Unit, Sub Power Supply Unit D Current Detector, Control Unit D1 Main Current Detector D2 Sub Current Detector D3 Window comparator section E Operation control section, control means E1 Transistor switching circuit E2 Diode E3 Diode E4 Control circuit F Connector (corresponds to the power supply method using a computer network cable)

Claims (1)

In a power supply device configured to be able to supply power to another network device connected via one computer network cable,
A sub-power supply means capable of supplying a low-voltage sub-power whose maximum output current is limited to a predetermined current value or less to the computer network cable;
Main power supply means capable of supplying main power required by other network devices connected via the computer network cable,
The sub power supply unit is connected to the computer network cable, and the main power supply unit is connected to the computer network cable only when a current value flowing through the computer network cable is within a predetermined range. Power supply device comprising control means for controlling the power supply as described above.

Images