WO2014020029A1

WO2014020029A1 - Electronic apparatus for power over ethernet and method

Info

Publication number: WO2014020029A1
Application number: PCT/EP2013/066015
Authority: WO
Inventors: Rudolf Häußermann
Original assignee: Fujitsu Technology Solutions Intellectual Property Gmbh
Priority date: 2012-07-31
Filing date: 2013-07-30
Publication date: 2014-02-06
Also published as: DE102012106995B3

Abstract

The invention relates to an electronic apparatus (10), particularly a computer, thin client or zero client, for connecting to an Ethernet network and for operation by Power over Ethernet, wherein the electronic apparatus (10) has the following: - an interface (1) for Power over Ethernet, with which the electronic apparatus (10) can be connected to an Ethernet network via a wiring section, wherein the electronic apparatus (10) is set up both for data exchange and also for supplying current via such a wiring section; - a measuring unit (3), with the aid of which the power consumption of an external wiring section connected upstream of the interface (1) can be determined via the interface (1); and - a control unit (5) which establishes a maximum power consumption (Pmax) of the electronic apparatus (10) permissible using Power over Ethernet as a function of the determined power consumption of the external wiring section and monitors the compliance of the thus-established maximum permissible power consumption (Pmax) of the electronic apparatus (10).

Description

description

Electronic device for Power-over-Ethernet and method The invention relates to an electronic device for Connecting ^¬ SEN to an Ethernet network and to operate through Power over Ethernet. The invention further relates to a method for operating such an electronic device. The electronic device can be, for example, a PC, a laptop or another computer, which has its own working and / or hard disk space and, if necessary, also drives for readable media, such as DVD / CD drives or optical drives ^¬ works. Alternatively, the electronic device can be a Thin Client or Zero Client, which does not need its own working and hard disk space and drives of its own and uses resources from the Ethernet network, such as the operating system or the software for its own operation from the Ethernet Network.

In particular, the electronic device is a device intended for Power-over-Ethernet, which not only exchanges data via the Ethernet network, but is also supplied with power via the network. The electronic device can in particular for one of the Power over Ethernet specifications

IEEE 802.3 af ("PoE") or IEEE 802.3 at ("PoE +"). These standards of Power over Ethernet require that two (or all four) pairs of the Ethernet cable are used or supplied with the power supply; a separate power cord for powering the electronic device is eliminated. Under Power-over-Ethernet, the electrical power that the network provides to consumers, ie electronic devices (terminals), is limited by default to about 15.5 W under PoE and to about 30 W under PoE +. If this standard ^{value of} the power consumption is exceeded, the switch or midspan switches off the electronic device connected to it. Power over Ethernet devices must therefore control their own power consumption so that the network-side default value of the maximum allowable power consumption is never exceeded. For this, the devices can temporarily disable example, some of their own compo ^¬ nents (such as internal power consumers or interfaces).

As actual, internally monitored ceiling on the maximum allowed power consumption of electronic devices with Power-over-Ethernet is device independent and vendor-independent well capped akzep ^¬ advantage so far, which is lower by a few watts as the monitored by the Mi ^¬ dspan default. The difference between the two values is due to the fact that even the line between the midspan and the terminal, ie the power over Ethernet cable itself consumes elekt ^¬ rische performance due to its own ohmic resistance. The amount of this unusable power consumption depends on the length of the Ethernet cable.

To electronic devices for Power over Ethernet manufacturer-side regardless of the length of the later used

Ethernet cables are traditionally based on a high, even under unfavorable circumstances still sufficient value for the cable loss of the cable (based on 100 m cable length) for the Ethernet cable; the electrical tronic device then monitors by this amount verrin ^¬ siege upper limit as the limit of one's maximum admissible ^¬ gen power consumption. Under PoE +, for example, the generally accepted limit is approximately 4.5 W lower than the network-supplied power of about 30 W and thus be ^¬ contributes about 25.5 W for the information to be monitored maxi- mum power of the terminal, and is under PoE The limit for the maximum power consumption of the terminal about 13 W. It is the object of the invention to provide an electronic device for Power over Ethernet, which is reliably operated under Power over Ethernet with a higher power consumption, without the risk of unwanted shutdown of the device through the network.

This object is achieved by an electronic apparatus according to claim 1. ^¬ and by a method according to claim 15 °. The device according to claim 1 has a measuring unit which is connected to the interface and makes it possible to measure via the interface, the electrical power consumption of an interface upstream, the external line route. The measuring unit performs a measurement to determine the power loss of an externally connected Ethernet cable. The electronic device also monitors - unlike a conventional terminal - not only its own power consumption, but also those of the cable to which it is connected. The maximum allowable power consumption of the electronic device itself is determined by its control unit, depending on the determined power consumption of the external Ethernet cable.

As a result, the power consumption of the electronic device is no longer limited by a static value as hitherto, but dynamically and depending on the actual power consumption. loss of the connection cable can be optimized. In particular, it is now possible to determine whether and by what difference amount the actual power loss of the upstream Ethernet cable is less than the generally assumed loss value for the cable, and the limit value for the maximum permissible power consumption of the electronic device itself can be determined by this Increase difference in performance. The electronic device described here controls itself so that it can accommodate a higher power than a conventional terminal for Power over Ethernet, without the risk that the network switches off the power supply of the device because of high power consumption. Some embodiments will be described below by way of example with reference to the figures. Show it:

1 shows an electronic device according to one embodiment ^¬ shape, which is connected to an Ethernet network,

Figure 2 shows a concrete embodiment of the electronic device of Figure 1, Figure 3 shows an exemplary embodiment of the electronic device with respect to the measuring unit and

Figure 4 shows an exemplary time course of the set by the electronic device upper limit of their own maximum power consumption.

FIG. 1 schematically shows an electronic device 10 which is connected via a line 2 to an Ethernet network 20 or a network component 20a (such as a midspan or a switch) is connected. The line 2 is an Ethernet cable, which serves for data transmission and at the same time for the power supply of the electronic device 10 by Power over Ethernet (usually an RJ45 cable). At this line, the electronic device 10 is connected via its interface 1 or connectable. The electronic device 10 is for example a laptop or other computer, a thin client or a zero client. According to this application, the electronic device 10 has a measuring unit 3 and a control unit 5; both of which can optionally be present as a ge ^¬ isolated units or as parts of a single, coherent circuit unit. Figure 2 shows a more concrete embodiment of the elekt ^¬ ronic device 10, in which within the measuring unit 3, a computing unit 7 is provided for calculating the external power consumption Pext. The arithmetic unit 7 can also be contained in the control unit 5 or be present as an independent unit. According to Figure 2 is in the

Control unit 5, a memory unit 9 is provided, in which, as shown, the maximum allowable power consumption Pmax of the electronic device 10 (or alternatively or additionally, the determined external power consumption Pext) can be stored. The memory unit 9 can also be arranged outside the control unit. The units 3, 5, 7 and / or 9 may be included in the microcontroller 15 of the electronic device 10. FIG. 2 also shows internal power consumers 17 of the electronic device 10 and interfaces 16 (for USB, for example) which, if necessary, can be switched off temporarily or operated at reduced power in order to avoid exceeding the permissible total Prevent power consumption of the electronic device 10 and the pre ^¬ switched line 2.

FIG. 3 shows a more specific, exemplary embodiment, in which circuit-technical details of the measuring unit 3 of the electronic device 10 are shown. In the area of the interface 1 eight connections la, lb, lh are shown, which are connected when plugged into a power over Ethernet cable (line 2) with its eight line wheels 2a, 2b, 2h. Two conductor cores each form a line pair (or line conductor pair). The network 20 or the network component (eg a midspan) to which the electronic device 10 is connected via the Ethernet cable, forms the voltage source for providing the supply voltage Uext (DC voltage). In the purely schematic example of FIG. 3, the supply voltage Uext is applied at least to the two line conductors 2a, 2h; the remaining leads are only indicated in sections. In the Pra ^¬ xis each of the two potentials of the supply voltage via a respective separate line pair or line pair is supplied. It can be used of the two potentials and two line pairs for each of ^¬.

Regardless of the concrete actual embodiment, however, with reference to FIG. 3 (for the sake of simplicity), only the conductor cores 2a (for the first potential of the supply voltage) and 2h (for the second potential) of which the supply voltage is at least transmitted are considered. The remaining cable cores can in the same way as the conductor wires la or lh with the

Voltage source of the network 20 and the interface 1 of the electronic device 10 connected and / or be further connected within the electronic device 10. The two line cores 2 a, 2 h are connected via corresponding contact terminals of the interface 1 (in this case, connections 1 a and 1 h) to two lines of the measuring unit 3, namely a first line 11 and a second line 12. Between both lines 11, 12 a test current generator 4 interposed, with a test current It (also a direct current) can be generated. The test current generated in the measuring unit 3 flows via the first line 11 and the second line 12 and via the connected line wires 2a, 2h of the Ethernet cable or the line 2 to the voltage source which provides the supply voltage Uext. The lines 11, 12 and the test current generator 4 are part of a measuring circuit of the measuring unit 3; they are provided in addition to other, not shown in Figure 3 lines leading away in the electronic device 10 of the eight contact terminals la, lb, lh the interface 1. As a result of the test current It (or the voltage change caused thereby) superimposed on the supply voltage Uext, the voltage existing between the lines 11, 12 changes relative to that voltage value which prevails between these two lines without test current. The conductors 2a, 2h of the external lead section 2 each represents an ohmic resistance R, whose size is unknown at first - as well as the power consumption or Leis ^¬ tung loss along this line wires 2a, 2h. However, the circuit of the measuring unit 3 shown in FIG. 3 makes it possible to calculate these unknown quantities and, in particular, to determine the power consumption Pext of the external line 2. For this purpose, a voltmeter 6 is further provided in the measuring unit 3, which is connected to the first line 11 and the second Lei ^¬ tion 12. The voltmeter 6 is connected in parallel to the test current generator 4 between both lines 11, 12 and measures the actually occurring (and as a result of the test current) voltage between the lines 11, 12. Since the strength of the test current It and that with the aid of the voltmeter 6 measured voltage change are thus known, it can be calculated from them the power that is consumed along the external line 2 line. Here, the internal resistance of the voltage source providing the supply voltage Uext versor ^¬, opposite the ohmic resistor R along the line wires 2a, 2h negligible. FIG. 3 also shows two diodes 21, 22; they are not necessarily part of the measuring unit 3, but above ^¬ preferably in the range of the interface 1 of the first line

11 and the second line 12 (as well as all other of the contact terminals la, lh continuing lines) on. The diodes 21, 22 serve in particular to ensure the correct polarity when using crossover cables.

In order to determine the power consumption of the external line route, the test current generator 4 can in particular be configured such that it generates two differently high test currents It1, It2 in succession or at different times (incremental measurement). Their currents II,

12 are, for example, 300 mA and 100 mA, are chosen anyway sufficiently small, that in the two

Voltage measurements with the aid of the voltmeter 6 two mög ^¬ lichst widely spaced measurements (according to the course of the diode characteristic of the two diodes 21, 22) for the respective Voltage change between the first line 11 and the second line 12 result.

Figure 4 shows schematically an example of the altitude and the time course of the monitored from the electronic device 10 of its own limit value, the maximum permissible power consumption ^¬ Pmax. According to the standard PoE +, for example, the network 20 or its midspan 20a monitors compliance with a standard value Ps of 30 W as an absolute upper limit for the actual, shared power consumption of the electronic device 10 and the upstream Ethernet cable 2; this upper limit (of 30 W at PoE +) corresponds to the feed-in power of the midspan. A conventional electronic device would limit its own power consumption - regardless of the actual length of the upstream Ethernet cable - to the widely accepted value G (of 25.5 W for PoE +) and would not allow for higher power consumption. The herein described electronic device 10, however, limited their own power consumption Pmax immediately after switching on at the time tl at most for a short time, for example for Dau ^¬ he the measurement of the actual cable resistance R or the determination of the actual power consumption P ext of the Ethernet cable 2, to a such value, but then determines and monitors the limit for the maximum allowable power consumption of the electronic device 10, which results from the measurement or subsequent calculation. If, for example, in the context of the measurement (for example, by applying two differently high test currents Itl, It2 and respective measurement of the voltage change (a first voltage value U1 and a second voltage value U2 between the lines 11, 12), an external power supply If the Ethernet cable has been determined to be at 2 W, the electronic device 10 determines the difference between Ps and Pext (in this case 28 W) as the value of the maximum permissible (own) power consumption and monitors this value from the time t2 as long as the electronic device remains connected to the network and is used. Compared to a conventional computer, thin client or zero client the result is an additional Leis ^¬ tung reserve (in the above calculation example is it 2.5 W) which is hereby made available under Power-over-Ethernet, without a risk of (accidental) shutdown of the device through the network. In this way, for example, in situations where conventionally the device-internal power must be reduced, additional inter ^¬ ne power ^consumers or USB interfaces of the device 10 operate. The value Pmax stored in the memory unit 7 henceforth is preferably cleared the next time the device is intentionally switched off (intentional, initiated by the user) and is again determined every time the device is switched on.

Reference sign list

I interface

la, lb, lh contact connection

2 line route

2a, 2b, 2h line wire

3 measuring unit

4 test current generator

5 control unit

6 voltmeter

7 arithmetic unit

9 storage unit

10 electronic device

II first line

12 second line

15 microcontroller

16 more interfaces

17 power consumers

20 network

20a network component

21, 22 diode

G upper limit

It test current

Itl first test current

It2 second test current

P actual power consumption

Pext determined power consumption

Pmax maximum allowable power consumption

Ps default value

R resistance

t time

tl, t2 time

U voltage first voltage value second voltage value supply voltage

Claims

claims

An electronic device (10), in particular a computer, thin client or zero client, for connection to an Ethernet network and for operation via Power-over-Ethernet, the electronic device (10) comprising:

- An interface (1) for Power over Ethernet, with which the electronic device (10) via a Leitungsstre ^¬ bridge to an Ethernet network can be connected, wherein the electronic device (10) both for data exchange and for power supply via such a line is set up,

- A measuring unit (3), with their help on the

Interface (1) the power consumption (Pext) one of the interface (1) upstream, external line path can be determined, and

Defining a control unit (5) having a maximum allowable under Power-over-Ethernet power consumption (Pmax) of the electronic device (10) in dependence on the detected power consumption (P ext) of the external pipe section and compliance with the so Festge ^¬ stored maximum permissible - Power consumption (Pmax) of the electronic device (10) monitors.

Electronic device according to claim 1,

characterized in that

the measuring unit (3) has a test current generator (4) with which a test current (It) can be generated for determining the electrical power consumption (Pext) of an external line path. Electronic device according to claim 1 or 2,

characterized in that

the measuring unit (3) has at least one first line (11) and at least one second line (12) connected to contact terminals (la, lh) of the interface (1), wel ^¬ che under Power-over-Ethernet for forwarding a supply voltage ( Uext) are provided, and that the test current generator (4) between the first line (11) and the second line (12) is interposed to the generated test current (It) via the two lines (11, 12) to the Contact terminals (la, lh) of the interface (1) to conduct.

Electronic device according to claim 3,

characterized in that

the electronic device (10) between the interface (1) and the first line (11) and between the

Interface (1) and the second line (12) each having a diode (21, 22), wherein the diodes (21, 22), the current direction along the two lines (11, 12) specify, and that the test current generator (4) DC current as test current (It) to the two lines (11, 12) applies.

Electronic device according to claim 3 or 4,

characterized in that

the measuring unit (3) further comprises a voltmeter (6) which is interposed in parallel with the test current generator (4) between the first line (11) and the second line (12).

Electronic device according to claim 5,

characterized in that the test current generator (4) and the voltmeter (6) are connected to portions of the first (11) and the second line (12) which are separated from the interface (1) by the diodes (21, 22).

Electronic device according to claim 5 or 6,

characterized in that

the test current generator (4) and the voltmeter (6) are so controlled that, when the test current Gene ^¬ rator (4) a test current (It) is generated using the voltmeter (6) due to the application of the test ^¬ current (It) resulting change between the first

(11) and the second line (12) prevailing voltage

(U) is measured.

Electronic device according to one of claims 5 to 7, characterized in that the

, Measuring unit (3) is configured so that under ei ^¬ ner determination of the power consumption (P ext) generated an ex ^¬ ternal conduction route the test current generator (4) at different time periods, two different levels of test currents (Itl, It2), where (by means of the voltmeter 6) upon application of the respective test ^¬ current (Itl, It2) a change in the voltage (U) between the first (11) and the second line (12) is measured.

Electronic device according to claim 8,

characterized in that

the test current generator (4) generates two test currents (Itl, It2) of different current intensity whose current intensity is below 500 mA, preferably below 300 mA.

10. Electronic device according to one of claims 1 to 9, characterized in that

the electronic device (10) comprises an arithmetic unit (7) which, from the current intensity (II, 12) of the generated test currents (Itl, It2) and from measured changes of voltage values (Ul, U2), an actual power consumption (Pext) of a external line, over which the electronic device (10) ver ^¬ provides voltage calculated.

11. Electronic device according to one of claims 1 to 10, characterized in that

the electronic device (10) comprises a memory unit (9) for storing the detected power ^¬ consumption (P ext) of a line section, to which the electronic device (10) is connected, and / or egg ^¬ nes calculated from this value for the maximum allowable power consumption (Pmax) of the electronic device (10) is provided.

12. Electronic device according to one of claims 1 to 11, characterized in that

the control unit (5) the difference between a standard value (Ps) of the power consumption, which provides the Ethernet network for electronic devices and upstream lines together maximum, and ei ^¬ nem determined power consumption (Pext) of a line to which the electronic device (10 is attached ^¬ closed), (as the value of the maximum permissible power consumption Pmax) of the electronic device (10) sets and an actual power consumption of the electronic device (10) up to the level of that value of the maximum permissible power consumption (Pmax) permits.

13. Electronic device according to one of claims 1 to 12, characterized in that

the control unit (5) allows an upper limit value (G), which is maximally provided under power-over-Ethernet for the sole power consumption of a power consumer alone without line sections, to be allowed by the actual power consumption of the electronic device (10), wherein the control unit ^¬ unit (5) ensures that the actual power consumption (P) of the electronic device at least does not exceed (10) the calculated value of the maximum permissible power consumption ^¬ (Pmax).

Electronic device according to one of claims 1 to 13, characterized in that

the electronic device (10) is configured so that the measurement of the power consumption (P ext) of the Lei ^¬ tung range, to which it is connected, and the Be ^¬ calculation of a maximum allowed power consumption

(Pmax) always after switching on the electronic Ge device (10) performs once and the determined value of its maximum allowable power consumption (Pmax) at least until the electronic device

(10) stops and / or stores.

Method for operating an electronic device (10), in particular a computer, a thin client or a zero client, by means of power-over-Ethernet, wherein the method comprises at least the following steps - determining the power consumption (Pext) of the electronic device (10 ) upstream, via which the electronic device (10) Power over Ethernet is powered by the electronic device (10) and

- setting a maximum ^¬ under Power-over-Ethernet transmitting power consumption (Pmax) of the electronic device (10) in function of the determined Leis ^¬ tung consumption (P ext) of the external line gap as well as monitoring compliance with the maximum allowable power consumption thus determined (Pmax) of the electronic device (10) by the electronic device (10).