JP2012039470A - Network equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide network equipment which has a configuration prepared for a sudden power interruption and which achieves miniaturization and energy conservation as well.SOLUTION: The network equipment 100 which functions as a PD in a PoE system comprises: a PoE power reception part 114 to receive the supply of electric power from a PSE in the PoE system; a power supply part 120 to receive the supply of electric power from a commercial power supply (main power supply/AC); and a relay 121 on the electric power supply path of the power supply part 120. The relay 121 supplies electric power to the power supply unit 120 from the commercial power supply when turned on. The PoE power reception part 114 turns on the relay 121 by using the electric power supplied by the PSE when the relay 121 is turned off.

Description

  The present invention relates to a network device, and more particularly to multiplexing of a power supply system using PoE (Power over Ethernet (registered trademark)) and downsizing of an apparatus.

  In a network device such as a hub of a local area network, it is considered to support PoE (Power over Ethernet (registered trademark)) for the purpose of increasing redundancy of power supply. PoE is a standard conforming to IEEE 802.3af.

  In the PoE method, a power receiving side device (hereinafter referred to as “Power Device: PD”) receives power supply from a power feeding side device (hereinafter referred to as “Power Source Equipment: PSE”) via a LAN cable. Therefore, when power consumption is low, it is not necessary to connect the power cable to the PD, or even if it is necessary to connect the power cable, the power supply source can be multiplexed to increase redundancy. is there. As a prior art of a network system using the PoE method, for example, there is one described in Patent Document 1.

  By the way, in an information processing apparatus equipped with a flash memory or a hard disk drive (hereinafter referred to as an HDD), if the power is turned off while writing to the flash memory or accessing the HDD, there is a problem that the recording may be broken. well known. Such a problem can be applied not only to an information processing apparatus such as a personal computer but also to a network device such as a LAN hub.

  In order to solve this problem, by using two power sources, a bypass is provided using a relay so that the power source is not cut off even if the power switch is turned off on one side of the power source. A technique for bypassing the power supply and turning off the relay by turning off the relay after the processing of the HDD is completed is already known (Patent Document 2).

  Patent Document 2 includes two power supply units that perform AC / DC conversion, and when a switch that turns on / off the supply of power to the power supply unit is turned off, the second power supply unit A technique is described in which a first power supply unit including a relay circuit that bypasses the input and output of the switch is notified, and the first power supply unit drives the relay circuit.

  The present invention is related to the point that the power-off is detected by software and the access to the HDD is saved, for example, the access to the HDD is terminated. However, there are two power sources that perform AC / DC conversion, and because AC / DC conversion is performed, the efficiency is low, and since power is supplied to both power sources when the power is on, the scale of the power source increases. There is a problem that it is not suitable for energy saving.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a network device that achieves both size reduction and energy saving while having a configuration for unexpected power interruption.

  In order to achieve the above object, according to a first aspect of the present invention, there is provided a network device functioning as a PD in the PoE system, a PoE power receiving unit that receives power supply from the PSE in the PoE system, and a power supply from a commercial power source. A power supply unit that receives power, and a relay on a power supply path of the power supply unit, and the relay supplies power from the commercial power source to the power supply unit when the relay is on, and the PoE power reception unit Provides a network device characterized by having first relay control means for turning on the relay using the power supplied by the PSE when the relay is in an off state. .

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the network apparatus which made the size reduction of an apparatus and energy saving compatible, having a structure in preparation for unexpected power failure.

It is a block diagram which shows the structure of the network apparatus which concerns on embodiment by this invention. 2 is a flowchart showing a flow of processing when power is turned on to the network device 100 of FIG. 1. 3 is a flowchart showing a flow of processing when the network device 100 in FIG. 1 is powered off.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Embodiments in which the invention is suitably implemented will be described below with reference to the drawings. In the following, description will be made centering on the PoE power receiving unit and power on / off operation of the PD (power receiving side device in the PoE system), which is the main part of the present embodiment.

FIG. 1 is a block diagram illustrating a configuration of a network device according to the present embodiment.
Although not limited, the PoE method in the present embodiment is a PoE (Power over Ethernet (registered trademark)) method compliant with IEEE 802.3af. A network device 100 shown in FIG. 1 is a power receiving device (PD) in the PoE system, and is connected to Ethernet (registered trademark) by wire, and is supplied with power from a counterpart network device. The counterpart network device that supplies this power is called PSE.

  As illustrated in FIG. 1, the network device 100 includes a control unit 110 and a power supply unit 120. The network device 100 includes an HDD (Hard Disk Drive) 130 that is a secondary storage device.

  First, the configuration of the power supply unit 120 will be described. The power supply unit 120 includes a first switch (hereinafter referred to as “SW1”), a relay 121, and an AC-DC conversion circuit 122 on a power supply line connected to a power supply plug of a commercial power supply in order from the power supply plug. And comprising.

  SW <b> 1 is a main power switch of the network device 100. When SW1 is on, the switch is closed and current is conducted, and when it is off, the switch is open and no current flows. In the present embodiment, SW1 is a loker type.

  When the relay 121 is in a relay-on state, the relay 121 supplies power from the commercial power source to the entire network device 100 including the control unit 110 via the AC-DC conversion circuit 122. On the other hand, when the relay is off, power from the commercial power supply is not supplied. That is, AC is cut off.

  Control for turning on or off the relay 121 is performed based on a relay on or off signal supplied from a PoE power receiving unit 114 and / or a relay control circuit 118 described later. The PoE power receiving unit 114 includes resistors R1 and R2 as shown in FIG. 1, a second switch (hereinafter referred to as “SW2”), and a DC-DC 116 (PD circuit 115). The relay ON / OFF signal supplied to the relay 121 is supplied by the DC-DC 116 based on the ON / OFF state of SW2.

  That is, means for supplying a relay on or off signal to the relay 121 including such SW2 functions as first relay control means. Further, the relay control circuit 118 functions as second relay control means.

  Next, the configuration of the control unit 110 will be described. The control unit 110 is roughly divided into a configuration for receiving power supply by PoE and a configuration for controlling the entire network device 100. First, the former will be described.

  The PoE power receiving unit 114 receives power via the LAN cable and the Ether transformer 112 inserted into the RJ45 connector 111. A PD circuit 115 is used for power reception. The power receiving mechanism itself is a standardized technology that receives power supply using a cable used for Ethernet wiring (IEEE 502.3af), and uses a technology well known to those skilled in the art.

  Only points related to the present embodiment will be described. In the PoE method, two steps of detection (DETECT) and classification (CLASSIFICATION) are taken until the PSE applies 48V to the LAN cable and starts power supply. In this embodiment, the detection step is related. In detection, it is checked whether or not a detection resistor of 25 KΩ is provided on the PD side. If it has a detection resistance of 25 KΩ, the PSE is determined to be a PoE-compatible PD device. On the other hand, when the PSE is connected to an ordinary NIC or the like, the PSE does not supply power because it is short-circuited at 150Ω.

  The PoE power receiving unit 114 includes resistors R1 and R2 as shown in FIG. 1, a second switch (hereinafter referred to as “SW2”), and a DC-DC 116 (PD circuit 115).

In the present embodiment, SW2 is a rocker type switch (SW2). SW2 is in a short mode when the power is off, and the resistance between Ethernet lines is a combined resistance value (150Ω) of R1 and R2 (25KΩ). In order to set the combined resistance value to 150Ω, the resistance value of R1 is set to 150.9Ω from the following equation.
(Resistance value of R1) = (25KΩ × 150Ω) / (25KΩ−150Ω)
= 150.9Ω

  When SW2 is turned on (Open), the resistance between Ethernet lines becomes 25 KΩ, and power is supplied from PoE. The supplied DC is input to the DC-DC conversion circuit 116 and becomes a power source for operating the relay 121.

  When the relay 121 is turned on, AC is supplied to the AC-DC conversion circuit 122 and power is supplied to the control unit 110. The relay control circuit 118 is activated by the electric power supplied to the control unit 110. The relay control circuit 118 holds the state of the relay 121. Therefore, once the relay 121 is turned on, the control unit 110 also has a function of maintaining the state of the relay 121 unless the SW1 is turned off.

  When the power is off, when SW2 is turned off (Close), the resistance between the Ethernet lines returns to 150Ω, and the power supply from PoE is stopped. At the same time, the power switch monitoring unit 117 detects "Low" and starts the shutdown process. First, after the access is completed while the HDD 130 is being accessed, the relay drive signal of the relay control circuit 118 is turned off and the relay 121 is turned off, so that the power can be turned off without destroying the data of the HDD 130.

  The power switch monitoring unit 117 detects the “High” level when the SW2 is in the open state, and detects the “Low” level when the SW2 is in the close state. Further, the transition from “High” to “Low” or vice versa is also detected.

  Relay control circuit 118 outputs a relay drive signal to relay 121. The relay 121 maintains an ON state while receiving the relay drive signal. Relay control circuit 118 also sends to relay 121 a relay drive signal that turns relay 121 off.

  The power switch monitoring unit 117 and the relay control circuit 118 belong to the components that control the entire network device 100 in the control unit 110 (the portion surrounded by the upper right rectangle in FIG. 1). This part additionally includes a central processing unit (CPU) 131, a memory 132, an Ether circuit 113 for processing packets received via the LAN, and an HDD control circuit 119.

  Next, the operation at power-on and power-off of the present embodiment having the above-described configuration will be described.

First, a description will be given of when the power is turned on.
FIG. 2 is a flowchart showing a processing flow when the network device 100 is powered on. A user who turns on the power to the network device 100 first turns on SW1 that is a rocker type switch (Step S101), and then turns on SW2 that is also a rocker type switch (Open).

  The subject of each step shown in the flowchart of FIG. 2 is in principle the processing operation of the network device 100, but for the convenience of explanation, only the steps S101 and S102 include processing in which the user is the subject. Note that steps S101 and S102 may be automatically performed by a software program or the like.

  When SW2 is turned on (Open), the line-to-line resistance value at PoE becomes 25 KΩ by the mechanism described with reference to FIG. 1 (step S103). When the line-to-line resistance value becomes 25 KΩ, the PSE detects (DETECT) and power is supplied from the PSE (step S104).

  The DC-DC conversion circuit 116 outputs a signal for driving the relay 121 with the supplied power supply as an input. As a result, the relay 121 is turned on (step S105). When the relay 121 is turned on, AC power is supplied to the AC-DC conversion circuit 122 (step S106), and power is supplied to the control unit 110 (step S107).

  Thereafter, the relay control circuit 118 in the control unit 110 outputs a relay drive signal, which is a signal for turning on the relay 121, to the relay 121 (step S108). That is, the relay 121 is also turned on in the relay control circuit 118. Thereby, the control unit 110 maintains the supply of power from the main power supply (commercial power supply / AC).

Next, a description will be given of when the power is turned off.
FIG. 3 is a flowchart showing a processing flow when the network device 100 is powered off. A user who shuts down the network device 100 and shuts down the network device 100 first turns off SW2 that is a rocker type switch (step S201).

  The subject of each step shown in the flowchart of FIG. 3 is the processing operation of the network device 100 in principle, but for the convenience of explanation, only the step S201 includes processing in which the user is the subject. Note that step S201 may be automatically performed by a software program or the like.

  When SW2 is turned off (Close), the line-to-line resistance value becomes 150Ω by the mechanism described with reference to FIG. 1 (step S202). When the line-to-line resistance value becomes 150Ω, it is detected by the PSE (DETECT), and the power supply from the PSE is cut off (step S203). Since the power is cut off, the DC-DC conversion circuit 116 is also turned off, and the signal for driving the relay 121 output from the DC-DC conversion circuit 116 is not output.

  When SW2 is turned off at the same time as steps S202 and 203, the power switch monitoring means 117 detects “Low” (step S204). Upon detection of “Low” by the power switch monitoring unit 117, the HDD control circuit 119 checks whether the HDD 130 is being accessed (step S205).

  While the HDD 130 is being accessed (step S205 / Yes), the HDD control circuit 119 waits until the access to the HDD 130 is completed and enters the shutdown state (step S206). Thereafter, the relay control circuit 118 outputs a signal for turning off the relay 121 (step S207). As a result, the relay 121 is cut off and the power supplied via the AC-DC conversion circuit 122 is stopped (step S208).

  According to the present embodiment, the main power supply (commercial power supply / AC) suddenly stops supplying power due to a power failure, or SW1 is turned off even though the HDD 130 is being accessed due to an inadvertent operation by the user. Even in such a case, since the power supply supplied from the PSE by PoE is used to wait until the operation of the HDD 130 is completed, it is possible to appropriately cope with an unexpected power failure. In addition, since the PoE method is used, unlike Patent Document 2 and the like, it is not necessary to provide two power supply systems, and the apparatus can be reduced in size and energy can be saved.

  In other words, according to the present embodiment, it is possible to provide a network device that achieves both a reduction in the size of the apparatus and energy saving while having a configuration in preparation for unexpected power interruption.

(Second Embodiment)
In the first embodiment described above, SW2 is a lock type switch, but in this embodiment, a non-lock type switch is used as SW2. In this embodiment, when the power of the network device 100 is turned off, switching from “High” level to “Low” level is performed instead of step S204 (monitoring of “Low” level by the power switch monitoring unit 117) in FIG. Process to detect.

  In the present embodiment, once the power is turned on, it is not necessary to use the PoE power supply. Therefore, further energy saving is realized as compared with the power consumption in the first embodiment.

(Image forming device)
Each of the embodiments described above is also effective when applied to an image forming apparatus such as a network compatible printer. Recently, in the technical field of image forming apparatuses, an increasing number of models are equipped with HDDs for purposes such as security printing. When each of the embodiments is applied to such an image forming apparatus, the HDD can be safely terminated using PoE when the main power supply is turned off. Compared with a configuration that does not use PoE (for example, the technology described in Patent Document 2 that prepares two power supplies), the power supply size can be made small and compact, and the power of PoE is used when the main power switch is not operated. Therefore, power consumption can be reduced.

DESCRIPTION OF SYMBOLS 100 Network apparatus 110 Control part 111 RJ45 connector 112 Ether transformer 113 Ether circuit 114 PoE power receiving part 115 PD circuit 116 DC-DC conversion circuit 117 Power switch monitoring means 118 Relay control circuit 119 HDD control circuit 120 Power supply part 121 Relay 122 AC-DC Conversion circuit 130 HDD
SW1 Main power switch SW2 PD circuit power switch R1, R2 Resistance

JP 2006-260108 A Japanese Unexamined Patent Publication No. 07-006101

Claims (7)

A network device that functions as a PD in the PoE system,
A PoE power receiving unit that receives power from the PSE in the PoE system;
A power supply that receives power from a commercial power supply;
A relay on the power supply path of the power supply unit;
With
When the relay is in an on state, the power is supplied from the commercial power source to the power source unit.
The PoE power receiving unit includes a first relay control unit that turns on the relay using electric power supplied by the PSE when the relay is in an off state.   The network device according to claim 1, wherein the first relay control unit turns on the relay for a predetermined time even when the supply of power from the commercial power supply is cut off.   3. The network device according to claim 2, wherein the predetermined time is a time until completion of a termination process of a built-in hard disk drive.   4. The network device according to claim 1, wherein the first relay control unit is a switch that switches a resistance value of the PoE power receiving unit. 5.   5. The PSE detects a change in the resistance value when the switch is switched from a state in which the relay is turned on, and stops supplying power to the PoE power receiving unit. The described network equipment.   6. The network device according to claim 4, further comprising second relay control means for receiving power supplied from the power supply unit and maintaining the relay on.   The network device according to claim 6, wherein the switch is of a non-locking type.

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