JP2007281970A - Electrical power receiving circuit and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent operation failure in the electrical power receiving side when only one of a pair-cable is broken, or when only one pin generates poor-contact in a connector in the electrical power receiving circuit for receivng the electrical power remotely fed, using the identical potential for the pair-cable. <P>SOLUTION: The electrical power receiving circuit receives electric power supplied remotely using the identical potential for a pair-cable. This electrical power receiving circuit includes common mode filters 13 and 14 connected to an electrical power receiving pair-cable and a detecting means 18 for detecting fluctuations in the receiving current including detecting coils 21 and 22 to a magnetic circuit of common field filters 13 and 14. Thereby, defective connection of cable and connector is judged from the detecting result of the detecting means 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power receiving circuit and a power receiving apparatus that receive power supplied remotely using a pair of cables such as twisted pair wires.

  IEEE 802.3af is standardized as a typical example of a remote power feeding system using a twisted pair wire of an Ethernet (registered trademark) cable. When the Ethernet (registered trademark) cable is category 5, there are 4 pairs of twisted pair wires, and power is supplied from two pairs of twisted pair of communication wires, and power is supplied from two pairs of twisted pairs of unused wires that are not used for communication. .

  A conventional power receiving circuit will be described with reference to FIG. The four pairs of twisted pair wires 20 are connected to the RJ45 connector 10 of the power receiving apparatus and supplied with power. First, in the method of supplying power from two pairs of vacant lines, the paired wires 4 and 5 of the RJ45 connector 10 and the 7 and 8 pins of the RJ45 connector 10 are respectively connected (shorted) on the power supply side and the power reception side. A voltage of the same potential is supplied to the pair line. The pair wires are connected to each other on the power receiving device side, and then connected to the power reception control circuit 17 through the diode bridge 16.

  The power reception control circuit 17 exchanges signals with the power supply side, monitors the power supply voltage and current consumption, and controls the connection with the subsequent circuit. Furthermore, in the method of supplying power using two pairs of communication lines, power is supplied and received from the center tap of the communication transformer used on the power supply side and the power reception side, and the RJ45 connector 10 has pins 1 and 2 and 3 and 6 pins. These two pair wires are supplied with the same potential voltage.

  On the power receiving device side, each pair line is connected to Ethernet (registered trademark) transformers 31 and 32, and a signal from the center tap on each primary side passes through the diode bridge 15 and is similar to the diode bridge 16, the power reception control circuit 17. Connected to. Signals TX and RX on the secondary side of the Ethernet (registered trademark) transformers 31 and 32 are connected to an Ethernet (registered trademark) PHY (not shown) for communication.

  Further, as a conventional example different from the standard, there is a method of supplying power to each pair of wires using a transmission line and a reception line using a UTP cable (see, for example, Patent Document 1 and Patent Document 2). And in the example of the said patent document, the circuit which detects abnormality, such as a short circuit and a disconnection, is added from the voltage and impedance of a feeder.

JP 2000-134228 A Japanese Patent No. 3105875

  In the method of simultaneously sending the voltage of the same potential to the twisted pair wire, if only one of the pair wires is disconnected or if only one of the connector pins has a poor contact, a failure will occur if the power consumption on the power receiving side is small. However, when the power consumption on the power receiving side increases, the power supply voltage drops due to the impedance of the cable or connector, causing malfunctions.

  In the method of feeding power from two pairs of empty lines, since two of the paired wires are connected on the power feeding side and the power receiving side, it is difficult to judge a cable failure from the voltage and the impedance of the cable as in the conventional example. It was impossible.

  In addition, even if the power is fed using two pairs of communication lines, even if the DC impedance of only one pair of wires is high, communication is possible if the AC impedance with respect to the signal frequency is low. A similar malfunction occurs. Further, since the two paired wires are connected to the power supply side and the power reception side transformers, it is difficult to determine the cable failure from the voltage and the impedance of the cable as in the conventional example.

A power receiving circuit of the present invention is a power receiving circuit that receives power remotely supplied to a pair of paired wires using the same potential, the common mode filter connected to the pair of power receiving pair wires, and the common mode And detecting means for detecting a variation in received current by attaching a detection coil to the magnetic circuit of the filter, and determining abnormality of connection of a cable or a connector from a detection result of the detecting means.
The power receiving circuit of the present invention is a power receiving circuit that receives power that is remotely fed simultaneously with a communication signal using the same potential for a pair of pair wires, and is a signal transformer connected to the pair of power receiving pair wires. And detecting means for detecting a variation in received current by attaching a current detecting coil to the magnetic circuit of the signal transformer, and determining abnormality of connection of a cable or a connector from a detection result of the detecting means. Features.
The power receiving circuit of the present invention is a power receiving circuit that receives power that is remotely fed using the same potential to a pair of paired wires, and a current detection coil is attached to each of the paired power receiving pair wires. Detecting means for detecting the received current, and comparing the current detected by the detecting means to determine an abnormality in connection of the cable or the connector.
A power receiving device of the present invention is a power receiving device that receives power that is remotely fed using the same potential to a pair of paired wires, and includes at least one power receiving circuit described above.

According to the power receiving circuit of the present invention, it is possible to easily detect a failure of only one of the pair wires, and it is possible to prevent a problem that causes a malfunction during the operation of the power receiving device. In addition, since the detection method is performed in an electrically non-contact manner with the line being fed, impedance matching is not affected. Furthermore, since the impedance of the paired wires as well as the disconnection can be detected as abnormal even when unbalanced, deterioration of the cable and connector can be detected.
Further, in the power receiving device of the present invention, the abnormality can be easily confirmed by displaying the abnormality. For example, in application to a network camera as a power receiving device, it is possible to quickly respond to an abnormality by notifying the abnormality through the network, and to maintain a main function by restricting some of the sub-functions that consume a lot of power. You can continue.

  The power receiving circuit of the present invention detects a connection failure of a cable or a connector by detecting a balance of currents fed using a twisted pair wire. Furthermore, when an abnormality is detected, it is a device that has a display function to display it. For example, in a network camera, when an abnormality is detected, the abnormality is reported through the network, and the main functions such as video and communication are excluded. This limits the sub-function that requires a large amount of current. Hereinafter, preferred embodiments will be described.

(First embodiment)
A power reception circuit in the power reception device according to the first embodiment of the present invention will be described with reference to FIG. The same elements as those of the conventional example shown in FIG. First, a method at the time of power feeding using a pair of empty wires of the cable 20 will be described.

  Two pair wires of RJ45 connector 10, 4 pins and 5 pins, and 7 pins and 8 pins are connected to the power receiving device by RJ45 connector 10, and after passing through common mode filters 13 and 14, are connected to diode bridge 16.

  Here, the current detection coils 23 and 24 are connected to the magnetic circuit of the common mode filters 13 and 14, and outputs C and D thereof are connected to inputs of the detection circuits 27 and 28 of the abnormality detector 19. The abnormality detection method of the abnormality detector 19 will be described. In the normal operation, a current equal to the twisted pair wire flows, so that the magnetic field lines of the magnetic circuits of the common mode filters 13 and 14 cancel each other and the signals C and D are not detected.

  However, if there is an abnormality in the cable or connector, a difference occurs in the current of the twisted pair wire, and a signal is detected from one or both of C and D.

  The detected signal is alternating current, but in the case of a normal power receiving device, the current consumption varies during operation, and an abnormality is detected based on whether or not this change is detected.

  Further, the detection circuits 27 and 28 amplify the C and D signals, and generate an abnormal signal when a reference level that is determined to be abnormal is exceeded.

  Next, a method during power feeding using a pair of signal lines of the cable 20 will be described. The two pair wires of RJ45 connector 10 are connected to RJ45 connector 10 and then receive power from the center tap on the primary side of each of Ethernet (registered trademark) transformers 11 and 12 through diode bridge 15. Connected to the control circuit 17.

  Here, coils 21 and 22 for current detection are connected to the magnetic circuit of the Ethernet (registered trademark) transformers 11 and 12, and outputs A and B thereof are connected to inputs of the detection circuits 25 and 26 of the abnormality detector 18. .

  Here, a method of detecting an abnormality of the abnormality detector will be described. In normal operation, the same current flows in the power supply of the twisted pair wire, so that only the component of the communication signal flows through the magnetic lines of the magnetic circuit of the Ethernet (registered trademark) transformers 11 and 12, and the components of the power supply current cancel each other. Only the component of the communication signal is detected.

  However, if there is an abnormality in the cable or connector, a difference occurs in the feeding current of the twisted pair wire, and a signal other than the communication signal component is detected from one or both of A and B.

  The signal detected here is alternating current as described above. Further, the detection circuits 25 and 26 amplify the signals A and B, and generate an abnormal signal when the signal component obtained by subtracting the communication signal component exceeds a reference level for determining that it is abnormal.

  As described above, by providing the above-described abnormality detection circuit in a device that receives power transmitted from a power supply device using four pairs of twisted pair wires, it is possible to detect a cable abnormality or a connector connection failure.

  In this embodiment, detection circuits are provided for both the pair line on the communication line side and the pair line on the empty line side. However, the detection circuit may be provided only on one side when the power supply side method is known in advance.

  Further, when an abnormality is detected, the abnormality may be displayed using an LED or the like on the power receiving device.

(Second Embodiment)
A power receiving circuit in the power receiving apparatus according to the second embodiment of the present invention will be described with reference to FIG. The same elements as those in FIGS. 1 and 4 are denoted by the same reference numerals.

  Since the method at the time of power feeding using a pair of empty wires of the cable 20 is the same as that in the first embodiment, the description thereof is omitted.

  Next, a method during power feeding using a pair of signal lines of the cable 20 will be described. Two pair wires of RJ45 connector 10 are connected to the power receiving device by RJ45 connector 10 and connected to Ethernet (registered trademark) transformers 31 and 32 through common mode filters 33 and 34, respectively. Is connected to the diode bridge 15 from the center tap on the primary side.

  Here, coils 35 and 36 for current detection are connected to the magnetic circuits of the common mode filters 33 and 34, and their outputs A 'and B' are connected to the same abnormality detector and detection circuit as in the first embodiment. Is done.

  Here, a method of detecting an abnormality of the abnormality detector will be described. In normal operation, the same current flows through the twisted pair wires. Therefore, only the component of the communication signal flows through the magnetic field lines of the magnetic circuits of the common mode filters 33 and 34, and the components of the supply current cancel each other. Only the component of the communication signal is detected.

  However, if there is an abnormality in the cable or connector, a difference occurs in the feeding current of the twisted pair wire, and a signal of a component other than the communication signal is also detected from one or both of A ′ and B ′.

  The signal detected here is alternating current and the operation of the abnormality detector is as described above. Also in this case, it is possible to detect a cable abnormality or a connector connection failure by providing the above-described abnormality detection circuit in a device that receives power transmitted from a power supply device using four pairs of twisted pair wires.

  In this embodiment, detection circuits are provided for both the pair line on the communication line side and the pair line on the empty line side. However, the detection circuit may be provided only on one side when the power supply side method is known in advance. Further, when an abnormality is detected, the abnormality may be displayed using an LED or the like on the power receiving device.

(Third embodiment)
A power reception circuit in the power reception device according to the third embodiment of the present invention will be described with reference to FIG. The same elements as those in FIGS. 1 and 4 are denoted by the same reference numerals.

  A method at the time of power feeding using a pair of empty wires of the cable 20 will be described for two pairs of 7-pin and 8-pin of the RJ45 connector 10.

  The RJ45 connector 10 is connected to the power receiving device, and the paired wires are connected after passing through the current detection coils 44 and 45.

  The current detection coils 44 and 45 may be of a type capable of detecting only alternating current or a type capable of detecting including direct current.

  The detection signals E and E 'from the current detection coils 44 and 45 are connected to the inputs of the detection circuits 41 and 42 of the abnormality detector 40, and the detector 43 compares them.

  The abnormality detection method of the abnormality detector 40 will be described. In normal operation, a current equal to the twisted pair wire flows, so that the detection signals E and E ′ are E = E ′, but there is an abnormality in the cable or connector. A difference occurs in the current of the twisted pair wire, and E> E ′ or E <E ′.

  This detection signal is amplified by the detection circuits 41 and 42, compared by the detector 43, and an abnormal signal is generated when the difference exceeds a reference level for determining that it is abnormal.

  Although one pair of pair lines has been described, the same applies to the other empty line pair, and the detection of two pairs of communication lines is the same by performing comparison with a detector after deleting communication signal components. Can be.

(Fourth embodiment)
As a fourth embodiment of the present invention, an example when the power receiving apparatus is applied to a network camera will be described with reference to FIG.

  In the figure, reference numeral 50 denotes a network camera, and four pairs of twisted pair wires 20 are connected to the RJ45 connector 10 of the network camera 50 to perform power feeding and communication.

  Reference numeral 51 denotes the power receiving circuit unit described in the above embodiment, which supplies power to the network camera 50 and communicates with the CPU unit regarding an abnormality detection signal.

  When an abnormality is detected in the power receiving circuit unit 51, a display for notifying the abnormality is performed, and communication (report) for notifying the abnormality is performed through the network.

  The display notifying the abnormality may be displayed by an LED or the like on the network camera 50 main body, but may be superimposed on a part of the distribution image, or may be displayed as a warning on a part of the viewer.

  As communication for notifying abnormalities, in addition to sending with an image as described above, it may be sent to a communication destination such as a predetermined mail address.

  Further, the CPU unit, the network unit, and the imaging unit included in the main function unit 53 that is the main function unit of the network camera 50 are operated preferentially, and are sub function units that consume a lot of power. Control is performed to limit the functions of a motor control unit such as pan, tilt, and zoom included in 52 and an illumination unit such as infrared illumination.

  Regarding the function limitation, when the power consumption in the network camera 50 increases when the cable or the connector is abnormal, the power supply voltage is lowered, and malfunctions such as malfunction and disconnection of communication are prevented.

It is a figure which shows the power receiving circuit of the power receiving apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the power receiving circuit of the power receiving apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the power receiving circuit of the power receiving apparatus which concerns on the 3rd Embodiment of this invention. It is a figure which shows the power receiving circuit of the conventional power receiving apparatus. It is a figure which shows the structure of the network camera which concerns on the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 RJ45 connector 11 Ethernet (trademark) transformer 12 Ethernet (trademark) transformer 13 Common mode filter 14 Common mode filter 15 Diode bridge 16 Diode bridge 17 Power reception control circuit 18 Abnormality detector 19 Abnormality detector 20 Twisted pair wire 21 Coil 22 Coil 23 Coil 24 Coil 25 Detection circuit 26 Detection circuit 27 Detection circuit 28 Detection circuit 31 Ethernet (registered trademark) transformer 32 Ethernet (registered trademark) transformer 33 Common mode filter 34 Common mode filter 35 Coil 36 Coil 40 Abnormality detector 41 Detection circuit 42 Detection circuit 43 Detector 44 Current detection coil 45 Current detection coil 50 Network camera 51 Power receiving circuit section 52 Sub-function section 53 Main function section

Claims (7)

A power receiving circuit that receives power supplied remotely by using the same potential for a pair of pair wires,
A common mode filter connected to a pair of power receiving pair wires;
Detecting means for detecting variation in received current by attaching a detection coil to the magnetic circuit of the common mode filter;
A power receiving circuit, wherein abnormality of connection of a cable or a connector is determined from a detection result of the detection means. A power receiving circuit that receives power remotely supplied simultaneously with a communication signal using the same potential for a pair of pair wires,
A signal transformer connected to a pair of power receiving pair wires;
Detecting means for detecting variation in received current by attaching a current detection coil to the magnetic circuit of the signal transformer;
A power receiving circuit, wherein abnormality of connection of a cable or a connector is determined from a detection result of the detection means. A power receiving circuit that receives power supplied remotely by using the same potential for a pair of pair wires,
It has a detection means for detecting a received current by attaching a coil for current detection to each of a pair of received power pair wires,
An abnormality in connection of a cable or a connector is determined by comparing currents detected by the detection means.   A power receiving device that receives power that is remotely fed using the same potential to a pair of pair wires, wherein the power receiving device comprises at least one power receiving circuit according to claim 1.   5. The power receiving device according to claim 4, further comprising display means for displaying an abnormality when the abnormality is determined in the power receiving circuit.   6. The power receiving apparatus according to claim 4, further comprising a notification unit that notifies an abnormality through the network when an abnormality is determined by the power receiving circuit.   7. The power receiving apparatus according to claim 4, further comprising a control unit that limits a part of the function when an abnormality is determined by the power receiving circuit. Power receiving device.

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