JP5382818B2 - Communication circuit and communication method - Google Patents

Description

  The present invention relates to a communication circuit and a communication method that can reduce power consumption.

  As represented by IEEE (The Institute of Electrical Engineers) 802.3az and the like, there is an Ethernet (registered trademark) technology that suppresses power consumption in a time zone without traffic. IEEE 802.3az is commonly referred to as EEE (Energy Efficient Ethernet (registered trademark)). In Ethernet communication, normally, in a state where a link with an opposite device is established (link up), a prescribed idle pattern is transmitted during a time period when there is no data traffic. The power consumed for sending the idle pattern corresponds to the power consumption during data communication. EEE saves power compared to normal idle pattern transmission by periodically transmitting a refresh signal for maintaining the link state instead of the idle pattern and performing intermittent operation during a time period when there is no data traffic. Is intended. In EEE, the periodic transmission state of the refresh signal is called LPI (Low Power Idle).

  Although LPI can obtain the power saving effect at the time of link-up, there is a problem that the power saving effect cannot be obtained when the communication cable is not connected. On the other hand, Patent Document 1 describes a method of reducing power consumption of a LAN adapter by turning off a power supply relay and cutting off power supply to the LAN adapter when the modular jack is removed from the modular connector. . Patent Document 2 describes a method of reducing power consumption by powering down a physical layer processing unit (PHY unit) of a port that has not been used. Although any of the methods described in Patent Document 1 and Patent Document 2 can obtain a power saving effect, there is a problem that it takes time to perform a process for returning from the power saving state to the normal operation state.

  Note that the refresh signal transmission interval during intermittent operation in LPI (hereinafter referred to as LPI mode) is longer than the transmission interval of FLP (Fast Link Pulse), so that the refresh signal is transmitted more than the state in which FLP is transmitted. The power consumption is lower in the state of being. FIG. 9 is an explanatory diagram showing a comparison between the FLP transmission interval and the transmission interval during intermittent operation in the LPI. The standard value of the FLP transmission interval is set to 16 ± 8 ms. Further, according to EEE, the refresh signal transmission interval is 22 ms or less in order to maintain the link.

Japanese Patent Laid-Open No. 5-14359 JP 2009-49732 A

  The present invention provides a communication circuit that can save power when the communication cable is not connected, and can perform a link-up operation immediately after returning from the power saving state to the normal state when the communication cable is connected. An object is to provide a communication method.

A communication circuit according to the present invention is a communication circuit capable of communicating with other devices via a network, and includes a communication connector and physical layer processing means, and the physical layer processing means has a communication cable connected to the communication connector. When not, the communication signal is looped back, a link-up operation is performed, and the LPI mode is started .

A communication method according to the present invention is a communication method in a communication circuit capable of communicating with other devices via a network, and determines whether or not a communication cable is connected to the communication connector, and the communication cable is connected to the communication connector. If it is determined that it is not, the communication signal is looped back, a link-up operation is performed, and the LPI mode is started .

  According to the present invention, power can be saved when the communication cable is not connected, and a link-up operation can be performed immediately after returning from the power saving state to the normal state when the communication cable is connected.

1 is a block diagram showing a first embodiment of a communication circuit according to the present invention. It is a block diagram which shows a mode that a communication cable is connected to the communication circuit of 1st Embodiment. It is explanatory drawing which shows operation | movement of the communication circuit of 1st Embodiment. It is explanatory drawing which shows other operation | movement of the communication circuit of 1st Embodiment. It is a block diagram which shows 2nd Embodiment of the communication circuit by this invention. It is a block diagram which shows a mode that a communication cable is connected to the communication circuit of 2nd Embodiment. It is explanatory drawing which shows operation | movement of the communication circuit of 2nd Embodiment. It is explanatory drawing which shows other operation | movement of the communication circuit of 2nd Embodiment. It is explanatory drawing which shows the comparison with the transmission interval of FLP, and the transmission interval at the time of the intermittent operation in LPI. It is a block diagram which shows the principal part of the communication circuit by this invention.

Embodiment 1. FIG.
A first embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a first embodiment of a communication circuit according to the present invention. FIG. 1 shows a state of a communication circuit in the first embodiment when a communication cable is not connected. FIG. 2 is a block diagram illustrating a state in which a communication cable (cable 500) is connected to the communication circuit of the first embodiment.

  A communication circuit (hereinafter referred to as a power saving communication circuit) 100 includes an RJ45 connector 200, a PHY chip 300, and a transformer 400.

  RJ45 connector 200 includes a terminal portion 210 and a switch 220.

  The terminal unit 210 outputs the MDI signal 602 input from the PHY chip 300 to a communication cable connected to the terminal unit 210. Also, the MDI signal 602 input from the communication cable connected to the terminal unit 210 is output to the PHY chip 300.

  The switch 220 is a switch that is turned on or off by pressing the terminal portion 210 with a spring. The switch 220 is connected to the PHY chip 300 and inputs a detection signal 601 to the PHY 300. As shown in FIG. 2, when the cable 500 is inserted, the spring of the terminal unit 210 is pushed in, the switch 220 is turned on, and the detection signal 601 input to the PHY chip 300 is High (VCC voltage). become. When the cable 500 is disconnected, the spring of the terminal unit 210 returns to the state shown in FIG. 1, the switch 220 is turned off, and the detection signal 601 input to the PHY chip 300 becomes Low (GND voltage).

  The PHY chip 300 is a circuit that executes processing of the physical layer of the OSI reference model. The PHY chip 300 includes an EEE control unit 310, a PCS (Physical Coding Sublayer) unit 320, a PMA (Physical Medium Attachment) transmission unit 330, a PMA reception unit 340, an MDI (Medium Dependent Interface and LPF unit). Part 360.

  The EEE control unit 310 controls the EEE operation. The EEE operation is to perform transmission / reception control in the LPI mode by controlling the PMA transmission unit 330 and the PMA reception unit 340.

  The PCS unit 320 encodes data received from a MAC chip outside the PHY chip 300 and outputs the encoded data to the PMA transmission unit 330. Further, the data input from the PMA receiving unit 340 is decoded, and the decoded data is transmitted to the MAC chip.

  The PMA transmission unit 330 performs signal transmission. The PMA transmission unit 330 transmits data input from the PCS unit 320, FLP, a refresh signal in the LPI mode, and the like.

  The PMA receiving unit 340 receives a signal from the opposite device connected to the communication cable.

  The MDI unit 350 transmits and receives the MDI signal 602. The MDI unit 350 receives the MDI signal 602 from the terminal unit 210 of the RJ45 connector 200 via the transformer 400 and outputs it to the PMA receiving unit 340. Also, the MDI signal 602 input from the PMA transmission unit 330 is transmitted to the terminal unit 210 via the transformer 400. The MDI unit 350 shown in FIG. 1 is an example in accordance with 1000 BASE-T, which is a 1 Gbit / second LAN standard. The MDI signal 602 includes DA +/−, DB +/−, DC +/−, DD + / -Signal is included.

  The FLP control unit 360 receives the detection signal 601 from the switch 220 of the RJ45 connector 200. When the detection signal 601 is Low, the PMA transmission unit 330 is instructed to stop FLP transmission, and when the detection signal 601 is High, the PMA transmission unit 330 is instructed to start FLP transmission.

  The transformer 400 insulates the power-saving Ethernet circuit 100 from the transmission side device connected to the RJ45 connector 200. Further, an MDI signal is transmitted between the RJ45 connector 200 and the PHY chip 300.

  Next, the operation of this embodiment will be described.

  FIG. 3 is an explanatory diagram illustrating an operation of the power-saving communication circuit 100 according to the first embodiment when a communication cable is not connected.

  As shown in FIG. 3, when the cable 500 is disconnected from the RJ45 connector 200, the spring of the terminal portion 210 of the RJ45 connector 200 returns to the original state, and the switch 220 is turned off. At this time, the detection signal 601 becomes Low via an external resistor connected to GND.

  When the detection signal 601 is Low, the FLP control unit 360 of the PHY chip 300 determines that the cable is not connected and instructs the PMA transmission unit 330 to stop sending FLP. When receiving an instruction to stop sending FLP, PMA transmitter 330 stops sending FLP.

  FIG. 4 is an explanatory diagram illustrating the operation of the power-saving communication circuit 100 according to the first embodiment when a communication cable is connected.

  As shown in FIG. 4, when the cable 500 is connected to the RJ45 connector 200, the switch 220 is turned on by pressing the spring of the terminal portion 210 of the RJ45 connector 200. At this time, the detection signal 601 is connected to VCC and becomes High level.

  When the detection signal 601 is High, the FLP control unit 360 instructs the PMA transmission unit 330 to start sending FLP. When receiving an instruction to start sending FLP, PMA transmitter 330 starts sending FLP. The FLP transmitted from the PMA transmission unit 330 is output to the RJ45 connector 200 via the MDI unit 350. The RJ45 connector 200 sends the input FLP to the opposite device connected to the cable 500 via the cable 500.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings.

  FIG. 5 is a block diagram showing a second embodiment of the power saving communication circuit according to the present invention. FIG. 5 shows a state of the power saving communication circuit 100 of the second embodiment when the communication cable is not connected. FIG. 6 is a block diagram illustrating a state in which the cable 500 is connected to the power saving communication circuit 100 according to the second embodiment.

  As shown in FIG. 5, the PHY chip 300 includes an EEE control unit 310, a PCS unit 320, a PMA transmission unit 330, a PMA reception unit 340, an MDI unit 350, and a loop control unit 270.

  The loop control unit 270 performs loop back control of the MDI signal 602 output from the MDI unit 350. The loop control unit 270 receives the detection signal 601 from the switch 220 of the RJ45 connector 200. The loop control unit 270 includes a loop switch 271. As shown in FIG. 5, when the cable 500 is disconnected and the detection signal 601 is High, the loop switch 271 is turned off, and the MDI signal 602 is looped back inside the PHY chip 300. In addition, as shown in FIG. 6, when the cable 500 is inserted and the detection signal 601 is Low, the loop switch 271 is turned on, and the MDI signal 602 is not looped back, but in a normal route. Input / output.

  Other configurations of the PHY chip 300 in the second embodiment are the same as those in the first embodiment. 5 and 6, the transformer 400 is not illustrated, but is disposed between the RJ45 connector 200 and the PHY chip 300 and performs the same processing as in the first embodiment. 5 and 6, the FLP control unit 360 is not illustrated, but the PHY 300 may include the FLP control unit 360.

  Next, the operation of this embodiment will be described.

  FIG. 7 is an explanatory diagram illustrating an operation of the power saving communication circuit 100 according to the second embodiment when the communication cable is not connected.

  As shown in FIG. 7, when the cable 500 is disconnected from the RJ45 connector 200, the spring of the terminal portion 210 of the RJ45 connector 200 returns to the original state, and the switch 220 is turned off. At this time, the detection signal 601 becomes Low via an external resistor connected to GND.

  When the detection signal 601 is Low, the loop control unit 270 turns on the loop switch 271 provided therein. When the loop switch 271 is turned on, the DA + and DB +, DA− and DB−, DC + and DD +, and DC− and DD− signals are connected. Thus, when a connection state in which the opposite device exists is created in a pseudo manner, the PMA receiving unit 340 determines that the opposite device exists and performs a link-up operation. Thereafter, the PHY chip 300 operates in the LPI mode.

  FIG. 8 is an explanatory diagram showing the operation of the power saving communication circuit 100 of the second embodiment when a communication cable is connected.

  As shown in FIG. 8, when the cable 500 is connected to the RJ45 connector 200, the switch 220 is turned on by pressing the spring of the terminal portion 210 of the RJ45 connector 200. When the switch 220 is turned on, the detection signal 601 is connected to Vcc and becomes High level.

  The loop control unit 270 turns off the loop switch 271 when the detection signal 601 is High. When the loop switch 271 is turned off, the connection of each signal is released, and the PMA receiver 340 once performs a link-down operation. When the PMA receiver 340 performs a link-down operation, the LPI mode is stopped. Thereafter, the PMA transmission unit 330 starts sending FLP. At this time, if there is an opposite device at the end of the cable 500, it is linked up with the opposite device by auto-negotiation.

  As described above, according to the present embodiment, even when the communication cable is not connected to the RJ45 connector 200, the power supply by the LPI mode is performed without stopping the power supply of the PHY chip 300. Therefore, when the communication cable is connected, the link up operation can be performed immediately.

  In addition, since power saving is realized by operating in the LPI mode even when the communication cable is not connected, there is no need to newly provide a power saving mode when the communication cable is not connected.

  Further, since the PHY chip 300 controls the loop switch 271, control by the CPU or the like is not required, so that power consumption can be suppressed.

  FIG. 10 is a block diagram showing a main part of a communication circuit according to the present invention. As shown in FIG. 10, the communication circuit includes the communication connector 20 (corresponding to the terminal portion 210 in the RJ45 connector 200 shown in FIG. 1) and the physical layer processing means 10 (corresponding to the PHY chip 300 shown in FIG. 1). The physical layer processing means 10 is characterized in that it operates in the LPI mode when the communication cable 30 (corresponding to the cable 500 shown in FIG. 2) is not connected to the communication connector 20.

  In the above embodiment, the following communication circuit is also disclosed.

(1) The physical layer processing means 10 performs a link-up operation by looping back a communication signal (corresponding to the MDI signal 602 shown in FIG. 1) when the communication cable 30 is not connected to the communication connector 20. A communication circuit for starting the LPI mode.

(2) It is provided with connection detection means (corresponding to the switch 220 in the RJ45 connector 200 shown in FIG. 1) for detecting whether or not the communication cable 30 is connected to the communication connector 20, and the connection detection means includes a cable detection signal (see FIG. 1 is output, and the communication cable 30 is connected to the communication connector 20, the cable detection signal is set to a state with cable connection, and the communication cable 30 is disconnected from the communication connector 20. Is a communication circuit that turns the cable detection signal into a state without cable connection.

(3) When the cable detection signal is in the cable connection state, the physical layer processing means 10 cancels the loopback of the communication signal, performs the link-down operation, stops the LPI mode, and performs the link pulse ( A communication circuit that starts transmission of FLP.

DESCRIPTION OF SYMBOLS 10 Physical layer processing means 20 Communication connector 30 Communication cable 20 Physical layer processing means 100 Communication circuit (power-saving communication circuit)
200 RJ45 connector 210 Terminal unit 220 Switch 300 PHY chip 310 EEE control unit 320 PCS unit 330 PMA transmission unit 340 PMA reception unit 350 MDI unit 360 FLP control unit 370 Loop control unit 371 Loop switch 400 Transformer 500 Cable 601 Detection signal 602 MDI signal

Claims (3)

A communication circuit capable of communicating with other devices via a network,
A communication connector and physical layer processing means;
The physical layer processing means loops back a communication signal, performs a link-up operation, and starts an LPI mode when a communication cable is not connected to the communication connector. Comprising a connection detection means for detecting whether a communication cable is connected to the communication connector;
The connection detection means outputs a cable detection signal, and when a communication cable is connected to the communication connector, the cable detection signal is set to a state with cable connection, and when the communication cable is disconnected from the communication connector, It said cable detection signal to a state without a cable connection,
When the cable detection signal is in the cable connection state, the physical layer processing means cancels the loopback of the communication signal, performs the link down operation, stops the LPI mode, and starts sending the link pulse. The communication circuit according to claim 1 . A communication method in a communication circuit capable of communicating with other devices via a network,
It is determined whether a communication cable is connected to the communication connector. If it is determined that the communication cable is not connected to the communication connector, the communication signal is looped back, a link up operation is performed, and the LPI mode is set. A communication method characterized by starting .

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