JP6629704B2 - Communication control device - Google Patents

Description

  The present invention relates to a communication control device that performs power line communication using a power line.

  2. Description of the Related Art In recent years, a signal has been superimposed on a power supply line to transmit and receive a signal between a plurality of communication devices via the power supply line. In such a communication device, the power supply line is grounded via a bypass capacitor in order to attenuate noise that enters the communication device via the power supply line. Therefore, when a high-frequency signal is superimposed on the power supply line, the signal may be attenuated by the bypass capacitor, and the signal may not be transmitted to another communication device.

  Therefore, in the power line communication system described in Patent Document 1, the connection point between the input terminal of the converter and the bypass capacitor and the connection point between the power line and the output circuit that outputs the signal and the demodulation unit that receives the signal are provided. , An inductance element is inserted in series. That is, in the communication frequency band used for power line communication, by increasing the impedance of the path from the output circuit to the ground via the bypass capacitor, the signal output from the output circuit is suppressed from flowing into the capacitor, Signals are being transmitted to other communication devices.

JP 2006-108933 A

  In the above power supply system in which an inductance element is connected in series to the power supply line, when noise of a frequency higher than the communication frequency band is superimposed on a signal output from the output circuit, the noise is not removed by a bypass capacitor, and other signals are removed. It is input to the demodulation unit of the communication device. That is, the power supply system has a problem in that the noise removal performance of the bypass capacitor is reduced in a frequency range higher than the communication frequency band described.

  The present invention has been made in view of the above circumstances, and has as its main object to provide a communication control device that realizes power line communication without lowering noise removal performance.

  The present invention relates to a communication control device (10, 10A) that performs communication of communication signals via a power supply line (5) that is grounded via a noise countermeasure capacitor (Cp) and supplies power to a plurality of devices. -10F), and includes at least one communication filter (13, 13a, 131-133, 131E-133E) and at least one detection unit (14, 141-143). At least one communication band for communication via the power supply line is set to a lower frequency band than a frequency band removed from the power supply line through the capacitor. The communication filter includes a resistance element and a reactance element, is connected to the power supply line in parallel with the capacitor, and sets a communication band as a pass band. The detection unit is connected to a connection point between the resistance element and the reactance element, and detects a communication signal from an output of the communication filter.

  According to the present invention, since the communication band of the communication control device is set to at least one frequency band lower than the pass band of the capacitor for noise suppression, the communication signal does not flow into the capacitor and the communication filter does not flow. Transmitted to Since the communication filter uses the communication band as the pass band, the communication signal passes through the communication filter and is detected by the detection unit. Therefore, when the communication signal of the communication band is superimposed on the power supply line, it can be transmitted to the communication control device. Further, the communication filter is connected in parallel with the capacitor, and is not connected in series with the power supply line. Therefore, the insertion of the communication filter does not affect the pass band of the capacitor, and even if a frequency component higher than the communication band is superimposed on the power supply line, the frequency component flows into the capacitor and is removed from the power supply line. Therefore, power line communication can be realized without lowering the noise removal performance.

  Note that the reference numerals in parentheses described in this column and in the claims indicate the correspondence with specific means described in the embodiment described below as one aspect, and denote the technical scope of the present invention. There is no limitation.

1 is an overall configuration diagram of an in-vehicle network system. FIG. 2 is a configuration diagram of a communication control device according to the first embodiment. FIG. 3 is a diagram illustrating a configuration of a low-frequency filter unit according to the first embodiment. It is a figure which shows the frequency characteristic of impedance when there is no filter part, when a low frequency filter part is inserted, and when a coil is inserted. It is a figure which shows the noise elimination performance of a capacitor in the case without a filter part, when inserting a low frequency filter part, and when inserting a coil. FIG. 3 is a logic circuit diagram illustrating a configuration of a detection unit and a determination unit. 5 is a time chart illustrating operations of a detection unit and a determination unit. It is a lineblock diagram of a communication control device concerning a 2nd embodiment. It is a lineblock diagram of a communication control device concerning a 3rd embodiment. It is a lineblock diagram of a communication control device concerning a 4th embodiment. It is a figure showing a waveform of a communication signal. FIG. 4 is a diagram illustrating a waveform of a composite signal on which communication signals of a plurality of frequencies are superimposed. FIG. 4 is a diagram illustrating noise resistance when only a communication signal of one frequency is used. FIG. 4 is a diagram illustrating noise resistance when communication signals of a plurality of frequencies are used. It is a lineblock diagram of a communication control device concerning a 5th embodiment. It is a lineblock diagram of a communication control device concerning a 6th embodiment. It is a lineblock diagram of a communication control device concerning a 7th embodiment. It is a figure showing the composition of the low frequency filter part concerning other embodiments. FIG. 9 is a diagram illustrating frequency characteristics of impedance when the low-frequency filter units according to the first and other embodiments are inserted. It is a figure showing the pass characteristic of the low frequency filter part concerning a 1st and other embodiments.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.
(1st Embodiment)
<Configuration of in-vehicle network>
As shown in FIG. 1, in the present embodiment, an in-vehicle network system 200 mounted on a vehicle realizes communication according to a plurality of communication standards. Specifically, the in-vehicle network system 200 implements Ethernet communication, CAN communication, and LIN communication. The transmission paths 2 to 4 are transmission paths that connect a plurality of ECUs that perform high-speed communication according to the Ethernet standard, CAN standard, and LIN standard, respectively. The transmission paths 2 to 4 are connected to each other via the gateway 1. Ethernet is a registered trademark. The ECU is an electronic control unit, that is, an electronic control unit. CAN is a registered trademark and stands for Controller Area Network. LIN stands for Local Interconnect Network.

Each ECU constituting the in-vehicle network system 200 functions as a communication node, and executes various processes by appropriately using information transmitted and received via the in-vehicle network.
The gateway 1 is a repeater that bundles networks, and realizes high-speed communication between ECUs conforming to different communication standards by converting a signal corresponding to a predetermined communication standard into a signal corresponding to another communication standard.

  The power supply line 5 is a distribution line that is connected to each ECU and distributes the DC voltage of the battery 8 that is a vehicle-mounted battery to each ECU. In the present embodiment, a 12 V lead battery is used as the battery 8. In the figure, the power supply lines are indicated by thick lines.

  Further, the power supply line 5 is also used as a transmission path for transmitting a communication signal Ss that does not depend on a communication standard from a predetermined ECU to another ECU. Communication between ECUs conforming to different communication standards can be performed via the power supply line 5 without passing through the gateway 1. However, as will be described later, the transmission of the communication signal Ss via the power line 5 is a low-speed communication, so that the information amount of the communication signal Ss transmitted via the power line 5 is limited. In the present embodiment, the communication signal Ss is a signal including on / off information for instructing turning on or off of the power supply of the ECU and a target node ID for identifying the ECU to be communicated, and is a 3-bit ternary value. Modulated to waveform. The three values are 4V, 0V, and -4V. The target node ID corresponds to the target node information.

<Configuration of ECU>
Here, assuming that the communication signal Ss is transmitted from the ECU 100 to the ECU 10 via the power supply line 5, the configuration of the ECU 10 relating to power supply line communication will be described. The basic configuration of the ECU 10 is the same as a known configuration. In the present embodiment, the ECU 10 corresponds to a communication control device.

  As shown in FIG. 2, the ECU 10 includes a power control unit 11, a communication control unit 12, a microcomputer 20 (hereinafter, a microcomputer 20), and other processing units (not shown). I have. The ECU 10 selectively executes, as operation modes, a sleep mode in which only a part of the functions are operated to enter a low power consumption state, and a wake-up mode in which the functions are not limited. The power-off state of the ECU 10 corresponds to a sleep mode in which the power of the microcomputer 20 and the like is turned off, and the power-on state of the ECU 10 corresponds to a wake-up mode in which the power of the microcomputer 20 and the like is turned on. A noise removing unit 9 is connected between the power supply line 5 and the ground on the transmission side of the input terminal of the ECU 10.

  As shown in FIG. 3, the noise removing unit 9 includes a capacitor Cp for noise suppression, a so-called bypass capacitor. The capacitor Cp is an element whose impedance increases as the frequency component increases. The capacitor Cp blocks the low frequency component and allows the high frequency component to pass to the ground. Therefore, the low frequency component superimposed on the power line 5 is transmitted to the receiving side via the power line 5, and the high frequency component is removed from the power line 5. In the vehicle-mounted network system 200, the communication band Bs for communication via the power line 5 is set to a frequency band lower than the frequency band Bc removed from the power line 5 through the capacitor Cp. For example, the communication band Bs is set to a band around 10 Hz, and the communication frequency fs of the communication signal Ss is 10 Hz. In the present embodiment, the power line communication is performed at a very low frequency band, so that the communication is performed at a low speed. The capacitance of the capacitor Cp is, for example, 45 nF.

  The communication control unit 12 includes a low-frequency filter unit 13, a detection unit 14, and a determination unit 15. As shown in FIG. 3, the low-frequency filter unit 13 is a band-pass filter that includes an HPF and an LPF in two stages and uses the communication band Bs as a pass band Bf. The HPF is composed of a series body of a capacitor Ch and a resistor Rh. One end of the capacitor Ch is connected to the power supply line 5 and one end of the resistor Rh is grounded. The LPF is composed of a series body of a resistor R1 and a capacitor Cl, one end of the resistor R1 is connected to a connection point between the capacitor Ch and the resistor Rh, and one end of the capacitor Cl is grounded. As for the values of the respective elements, for example, the capacitances of the capacitors Ch and Cl are 1 μF and 0.1 μF, and the resistance values of the resistors Rh and Rl are 51 kΩ and 51 kΩ. The HPF cuts off a DC component superimposed on the power supply line 5, that is, a voltage component of the battery 8, and passes an AC component. The LPF passes a signal having a frequency of the pass band Bf among the AC components that have passed through the HPF. Therefore, the communication signal Ss is separated from the input signal input to the low frequency filter unit 13 and output. The low-frequency filter unit 13 includes only passive elements, and operates without receiving power. Further, since the low frequency filter section 13 does not include a coil, it can be provided in an IC constituting the ECU 10. Note that HPF is a High Pass Filter, and LPF is a Low Pass Filter.

  FIG. 4 shows frequency characteristics of the circuit impedances Z1 and Z3 when a communication filter is connected and the circuit impedance Z2 when no communication filter is connected. The circuit impedance Z1 is a configuration in which the low-frequency filter unit 13 as a communication filter is connected in parallel to the capacitor Cp, that is, the circuit impedance of the configuration of the present embodiment. The circuit impedance Z3 is a circuit impedance of a configuration in which a coil as a communication filter is connected in series between the capacitor Cp and the signal input terminal of the communication control device, that is, a configuration corresponding to the related art. The circuit impedances Z1 to Z3 are impedances when the input side on the receiving side is viewed from the transmitting side. FIG. 5 is a diagram showing the frequency characteristics of the noise removal performance of the capacitor Cp in the three cases shown in FIG. There is a correlation between the frequency characteristic of the circuit impedance and the frequency characteristic of the noise elimination performance. The higher the circuit impedance, the easier the communication is, and the lower the noise elimination performance.

  The frequency characteristic of the circuit impedance Z3 is equal to the frequency characteristic of the circuit impedance Z2 up to a frequency around 100 kHz. However, near the frequency of 100 kHz, the coil and the capacitor Cp resonate, and the circuit impedance Z3 is greatly reduced. In the frequency range of 100 kHz or higher, the circuit impedance Z3 increases as the frequency increases, and the noise removal performance decreases. Therefore, when the coil is connected in series to the capacitor Cp, the noise elimination performance in a high frequency region of a frequency of 100 kHz or more is lower than when the communication filter is not connected.

  On the other hand, the frequency characteristic of the circuit impedance Z1 is equal to the frequency characteristic of the circuit impedance Z2. That is, the low-frequency filter unit 13 has a role of only extracting the communication signal Ss, and does not affect the noise removal performance of the capacitor Cp. In this case, a circuit impedance high enough to enable communication is obtained in a frequency range lower than a frequency of approximately 100 kHz. Since the impedance used in general CAN communication is 60Ω, communication can be considered to be possible if the circuit impedance is 60Ω or more.

  The detection unit 14 is a circuit that detects the communication signal Ss from the output of the low-frequency filter unit 13, and operates by receiving the power supply output PS1 from the power control unit 11. The determination unit 15 is a circuit that determines whether or not the target node ID included in the detected communication signal Ss matches the own node ID stored in advance to identify the ECU 10 that is the own device. , And operates upon receiving the power supply output PS1 from the power supply control unit 11. In the present embodiment, the own node ID corresponds to the own node information. Hereinafter, details of the detection unit 14 and the determination unit 15 will be described with reference to FIGS. 6 and 7. FIG. 7 shows, in order from the top, a filter input signal at point A, a filter output signal at point B, a collation result of each bit at point C, a clock CK at point D, a collation result of all bits at point E, and a power supply. 3 shows a time chart of the turn-on or turn-off of FIG.

  The detection unit 14 includes two comparators 141 and 142 and one NOR circuit 143, and determines whether the communication signal Ss is a high level (hereinafter, HL) of 4V, a middle level (hereinafter, ML) of 0V, or It is determined whether the low level is 4 V (hereinafter, LL). When the communication signal Ss is HL, the output of the comparator 141 is 1 and the other outputs are 0. When the communication signal Ss is ML, the output of the NOR circuit 143 is 1 and the other outputs are 0. When the communication signal Ss is LL, the output of the comparator 142 becomes 1 and the other outputs become 0. In FIG. 7, the communication signal Ss has LV at the first bit, ML at the second bit, and HL at the third bit.

  Further, the detection unit 14 includes a clock signal generation unit 144. The clock signal generation unit 144 generates a clock signal by shifting the rising or falling edge of the first bit of the communication signal Ss by the bit period of the communication signal Ss. That is, the clock signal generation unit 144 generates a clock signal without using a clock element in order to suppress power consumption.

  The determination unit 15 includes a one-bit collation unit 15a and an all-bit collation unit 15b, and operates by receiving the power supply output PS1 from the power supply control unit 11. The one-bit matching unit 15a includes three XNOR circuits 151 to 153, an AND circuit 154, and memories No1 to No3. The memories No. 1 to No. 3 correspond to HL, ML, and LL, respectively, and the own node ID modulated into a ternary waveform is stored in advance for each bit. For example, when the three bits of the own node ID are LL, ML, and HL, respectively, (No1, No2, No3) = (0, 0, 1) is stored as the first bit. Further, (No1, No2, No3) = (0, 1, 0) is stored as the second bit, and (No1, No2, No3) = (1, 0, 0) is stored as the third bit. The first bit of the target node ID and the own node ID is a start bit indicating the head of the signal, and is set to LL or HL. The XNOR circuits 151 to 153 output 1 when the output of the comparator 141, the NOR circuit 143, and the comparator 142 match the values of the memories No1 to No3, respectively, and output 0 when they do not match. The outputs of the memories No1 to No3 are switched to the next bit at the falling timing of the clock signal. That is, the 3-bit value of each memory is sequentially output from the first bit, and is sequentially compared with the value of each bit of the communication signal Ss. The AND circuit 154 outputs 1 when all of the values of the XNOR circuits 151 to 153 are 1, and outputs 0 in other cases. That is, the AND circuit 154 outputs 1 when the level of the detected predetermined bit of the target node ID and the stored level of the predetermined bit of the own node ID match, and outputs 0 in other cases. I do.

  The all-bit collating unit 15b includes an AND circuit 155 and a flip-flop circuit 156 (hereinafter, FF circuit 156). The AND circuit 155 outputs 1 when the output of the AND circuit 154 and the non-inverted output Q of the FF circuit 156 are 1, and outputs 0 otherwise. The FF circuit 156 is preset at the timing when the power supply of the ECU 10 is turned on and off, and latches the output of the AND circuit 155 at the timing of the rising edge of the clock signal. That is, the FF circuit 156 continues to output 1 while the target node ID and the own node ID match, and outputs 0 when they no longer match. In FIG. 7, all bits of the target node ID and the own node ID match, and 1 is continuously output. The output of the FF circuit 156 latched by the third bit clock signal is defined as an output Fo.

  The power supply control unit 11 is a circuit that receives power from the power supply line 5, converts a supply voltage into a predetermined voltage suitable for the operation of each processing unit in the ECU 10, and supplies the predetermined voltage to each processing unit. As the power supply control unit 11, for example, a DCDC converter is used. The power control unit 11 controls power supply in the ECU 10 according to the on / off information of the communication signal Ss when the determination unit 15 determines that the target node ID and the own node ID match in all bits.

<Power supply control>
Hereinafter, the power supply control in the ECU 10 will be described. First, power supply control in the ECU 10 when the ECU 100 transmits a communication signal Ss to the ECU 10 via the power supply line 5 to activate the ECU 10 in the sleep mode will be described. When the output Fo is 1, the power control unit 11 determines that a power-on command to the ECU 10 has been received, and starts supplying the power supply output PS2 to the microcomputer 20 and the like. That is, the power control unit 11 switches the power of the microcomputer 20 and the like from off to on. As a result, the ECU 10 transitions to the wake-up mode. On the other hand, when the output Fo is 0, the power control unit 11 continues the sleep mode with the power of the microcomputer 20 and the like turned off. The power control unit 11 always supplies the power supply output PS1 to the detection unit 14 and the determination unit 15 used for power line communication regardless of the operation mode of the ECU 10. Thus, the communication signal Ss can be processed regardless of the operation mode of the ECU 10.

  Next, power supply control in the ECU 10 when the ECU 100 transmits a communication signal Ss to the ECU 10 via the power supply line 5 in order to stop the ECU 10 in the wake-up mode will be described. When the output Fo is 1, the power supply control unit 11 determines that the power off command to the ECU 10 has been received, and terminates the power supply of the power supply output PS2 to the microcomputer 20 and the like. That is, the power control unit 11 switches the power of the microcomputer 20 and the like from on to off. Thereby, the ECU 10 shifts to the sleep mode in which only the detection unit 14 and the determination unit 15 are supplied with power. On the other hand, when the output Fo is 0, the power control unit 11 continues the wake-up mode while keeping the power of the microcomputer 20 and the like on.

<Effect>
According to the first embodiment described above, the following effects can be obtained.
(1) The frequency fs of the communication signal is set to a frequency lower than the frequency band Bc passing through the capacitor Cp, and the pass band Bf of the low frequency filter unit 13 is set to a band including the communication frequency fs. Power line communication can be realized without lowering the removal performance.

  (2) By setting the communication frequency fs to a frequency lower than the frequency band Bc, the power line communication becomes a low-speed communication. However, by using the communication signal Ss as power on / off information for the ECU 10, communication can be performed without any problem even at a low speed.

(3) Power consumption can be reduced by controlling power supply to the microcomputer 20 and the like in the ECU 10 according to the power on / off information for the ECU 10.
(4) The power consumption of the ECU 10 can be reduced by configuring the low-frequency filter unit 13 only with passive elements, as compared with a case including the active elements.

  (5) By transmitting and receiving the communication signal Ss via the power supply line 5, communication can be performed between ECUs having different communication methods without using the gateway 1. As a result, power consumption in the in-vehicle network system 200 can be suppressed as compared with the case where the gateway 1 is used.

(2nd Embodiment)
<Difference from First Embodiment>
Since the second embodiment has the same basic configuration as the first embodiment, the description of the common configuration will be omitted, and the description will focus on the differences. The same reference numerals as in the first embodiment denote the same components, and refer to the preceding description.

  As shown in FIG. 8, the communication control unit 12A of the ECU 10A according to the second embodiment is different from the communication control unit 12 of the ECU 10 according to the first embodiment in that a communication unit 16 is provided. The transmission unit 16 operates upon receiving the power supply output PS1 from the power supply control unit 11. When the transmission unit 16 receives the target node ID of the power-on target or the power-off target from the microcomputer 20, the transmission unit 16 transmits the transmission signal Ss in which the target node ID is set to the power supply line 5 via the low-frequency filter unit 13. I do. In the first embodiment, the ECU 100 includes the transmission unit 16.

<Effect>
According to the second embodiment described above, the following effects can be obtained in addition to the effects (1) to (5) of the first embodiment.

  (6) The communication signal Ss can be received and transmitted from the ECU 10 via the power supply line 5. As a result, the communication signal Ss can be exchanged between the plurality of ECUs.

(Third embodiment)
Since the third embodiment has the same basic configuration as the first embodiment, the description of the common configuration will be omitted, and the description will focus on the differences. The same reference numerals as in the first embodiment denote the same components, and refer to the preceding description.

  As shown in FIG. 9, the ECU 10B according to the third embodiment is different from the ECU 10 according to the first embodiment in that the ECU 10B includes a detection unit 17 in addition to the power supply control unit 11 and the communication control unit 12. The detecting unit 17 operates by receiving the power supply output PS3 from the power control unit 11 and acquires the output of the low frequency filter unit 13. That is, the output of the low frequency filter unit 13 is input to the detection unit 17 and the detection unit 14, respectively. The detecting unit 17 detects the input of the communication signal Ss when the voltage value of the output voltage of the low-frequency filter unit 13 changes more than a preset threshold, and outputs the detection result to the power control unit 11. Thereby, the power supply control unit 11 can recognize the input of the communication signal Ss before the detection unit 14 detects the communication signal Ss.

  The power supply control unit 11 starts supplying the power supply output PS1 to the detection unit 14 and the determination unit 15 on the condition that the communication signal Ss is detected by the detection unit 17 as illustrated in the lowermost part of FIG. Then, when the determination by the determination unit 15 ends, the power supply control unit 11 ends the supply of the power supply output PS1. That is, the power control unit 11 supplies the power supply output PS1 to the detection unit 14 and the determination unit 15 only when processing the communication signal Ss. Further, the power supply control unit 11 always supplies the power supply output PS3 to the detection unit 17 regardless of the operation mode of the ECU 10. Thereby, regardless of the operation mode of the ECU 10, the input of the communication signal Ss can be detected. Here, the power consumption in the detection unit 17 is smaller than the power consumption in the detection unit 14 and the determination unit 15. Therefore, by adding the detection unit 17 and changing the components that constantly supply power from the detection unit 14 and the determination unit 15 to the detection unit 17, the power consumption of the entire ECU 10B is reduced although the number of components is increased.

<Effect>
According to the third embodiment described above, the following effects are obtained in addition to the effects (1) to (5) of the first embodiment.

  (7) Since the power consumption of the detection unit 17 is smaller than the power consumption of the detection unit 14 and the determination unit 15, the power is output to the detection unit 14 and the determination unit 15 only when the input of the communication signal Ss is detected. By supplying PS1, the power consumed by the ECU 10 can be reduced.

(Fourth embodiment)
<Difference from First Embodiment>
In the first embodiment, in communication via the power supply line 5, one communication band Bs is set, and transmission / reception of the communication signal Ss belonging to one communication band Bs is performed. On the other hand, in the fourth embodiment, in communication via the power line 5, a plurality of communication bands Bs are set, and transmission and reception of a composite signal Sa on which communication signals Ss of the plurality of communication bands Bs are superimposed is performed. What they do is different.

  When the communication signal Ss is transmitted via the power supply line 5 while the vehicle is stopped, conduction noise from the transmission-side ECU is hardly superimposed on the power supply line 5. However, when the communication signal Ss is transmitted via the power supply line 5 during traveling, conduction noise from the transmission side ECU is superimposed on the power supply line 5. If the frequency of the conducted noise is close to the communication frequency fs of the communication signal Ss, the ECU on the receiving side may not be able to correctly receive the communication signal Ss.

  In general, as a countermeasure against conducted noise on the power supply line 5, a frequency spreading method of spreading a signal frequency spectrum over a wide band and transmitting the signal is known. When the frequency spreading method is adopted, a large-scale signal is used for modulation and demodulation of a signal. A processing circuit is required. Therefore, the frequency spreading method consumes a large amount of power and is not suitable for the vehicle network system 200 in which the power consumption is to be suppressed. Therefore, in the present embodiment, transmission and reception of communication signals Ss of a plurality of transmission frequencies are performed in a frequency band that does not affect the capacitor Cp.

  Hereinafter, the configuration of the ECU 10C according to the present embodiment will be described with reference to FIG. Here, the configuration of ECU 10C will be described on the assumption that communication signal Ss is transmitted from power supply line 5 from ECU 100C to ECU 10C. The ECU 10C and the ECU 100C have the same configuration.

  In the present embodiment, three communication bands Bs1, Bs2, and Bs3 are set in a frequency band lower than the frequency band Bc removed from the power supply line 5 through the capacitor Cp. Specifically, in the present embodiment, the communication band Bs1 is set to a band centered at 10 Hz, the communication band Bs2 is set to a band centered at 100 Hz, and the communication band Bs3 is set to a band centered at 1 kHz.

  Therefore, the ECU 10C includes three transmission units 311, 312, 313, three frequency control units 321, 322, 323, three low frequency filter units 131, 132, 133, and three detection units 141, 142, 143. And three determination units 151, 152 and 153, and a power control unit 11. In FIG. 13, the microcomputer 20 and power supply lines from the power supply control unit 11 to the detection units 141, 142, 143, the determination units 151, 152, 153, and the microcomputer 20 are omitted.

  The transmission units 311, 312, and 313 transmit the communication signals Ss1, Ss2, and Ss3 of the communication frequencies fs1, fs2, and fs3 belonging to the communication bands Bs1, Bs2, and Bs3, respectively, at the same timing. The communication signals Ss1, Ss2, and Ss3 have the same waveform as shown in FIG. 11, and the communication frequencies fs1, fs2, and fs3 are 10 Hz, 100 Hz, and 1 kHz, respectively. Thereby, as shown in FIG. 12, the composite signal Sa on which the communication signals Ss1, Ss2, and Ss3 are superimposed is transmitted via the power supply line 5.

  The frequency control units 321, 322, and 323 control the frequencies of the communication signals Ss1, Ss2, and Ss3 transmitted from the transmission units 311, 312, and 313 to the communication frequencies fs1, fs2, and fs3, respectively.

  The low-frequency filter units 131, 132, and 133 are band-pass filters that set the communication bands Bs1, Bs2, and Bs3 to pass bands Bf1, Bf2, and Bf3, respectively. The low frequency filter units 131, 132, and 133 respectively extract the communication signals Ss1, Ss2, and Ss3 from the composite signal Sa. The configuration of each of the low-frequency filter units 131, 132, and 133 may be the same as the configuration of the low-frequency filter unit 13.

  The detection units 141, 142, and 143 are circuits that detect communication signals Bs1, Bs2, and Bs3 from the outputs of the low-frequency filter units 131, 132, and 133, respectively. The configuration of each of the detection units 141, 142, and 143 may be the same as the configuration of the detection unit 14.

  The determination units 151, 152, and 153 determine whether the target node IDs included in the communication signals Ss1, Ss2, and Ss3 detected by the detection units 141, 142, and 143 match the own node IDs, respectively. judge. Then, if they match, the determination units 151, 152, and 153 output an output Fo = 1 indicating that the power is on or on. The output Fo = 1 output from the determination units 151, 152, and 153 is integrated and transmitted to the power control unit 11. Since the output Fo of the determination units 151, 152, and 152 is "1" or "0", they can be integrated without using a device that requires signal processing. The configuration of each of the determination units 151, 152, and 153 may be the same as the configuration of the determination unit 15.

  When performing one-way communication from the ECU 100C to the ECU 10C, the ECU 10C may not include the transmission units 311, 312, 313 and the frequency control units 321, 322, 323. Also, the ECU 100C may not include the low frequency filter units 131, 132, 133, the detection units 141, 142, 143, and the determination units 151, 152, 153.

<Action>
FIG. 13 shows a time chart when the communication band is only the communication band Bs1 and the communication signal Ss is a signal of 10 Hz. Voltage Vsa indicates a signal voltage on power supply line 5 when conduction noise of 10 Hz is not superimposed on power supply line 5. The voltage Vsa is obtained by adding the voltage of the communication signal Ss to the voltage of the battery 8. The voltage Vsd indicates the voltage of the signal after the signal of the voltage Vsa is passed through the low-frequency filter unit 131 and subjected to AD conversion. The voltage Vsna indicates a signal voltage on the power supply line 5 when a conduction noise of 10 Hz is superimposed on the power supply line 5. The voltage Vsna is a voltage obtained by adding the voltage of the battery 8, the voltage of the communication signal Ss, and the voltage of the conductive noise. The voltage Vsnd indicates a voltage after the signal of the voltage Vsna is passed through the low-frequency filter unit 131 and subjected to AD conversion.

  When the voltage Vsd and the voltage Vsnd are compared, it can be seen that the waveform is greatly shifted, and the information of the communication signal Ss cannot be transmitted correctly. This is because the frequency of the conduction noise falls within the communication band Bs1, so that the conduction noise passes through the low-frequency filter unit 131, and the communication signal Ss and the conduction noise are not separated.

  On the other hand, FIG. 14 shows a time corresponding to FIG. 13 when the communication band is a communication band Bs1, Bs2, and Bs3, and the synthesized signal Sa is a signal obtained by superimposing the communication signals Ss1, Ss2, and Ss3 of 10 Hz, 100 Hz, and 1 kHz. The chart is shown. The voltage Vsd3 indicates the voltage of the signal after the signal of the voltage Vsa is passed through the low-frequency filter unit 133 and subjected to AD conversion. The voltage Vsnd3 indicates the voltage of the signal after the signal of the voltage Vsna is passed through the low-frequency filter unit 133 and subjected to AD conversion.

  When the voltage Vsd3 is compared with the voltage Vsnd3, the waveforms match, and it can be seen that the information of the communication signal Ss3 has been correctly transmitted. This is because the conduction noise is separated from the communication band Bs3, so that the conduction noise is cut off by the low-frequency filter unit 133, and only the communication signal Ss3 is extracted from the low-frequency filter unit 133. That is, by using a plurality of communication bands, even if the frequency of the conducted noise is in one of the communication bands, information is correctly transmitted in another communication band. The plurality of communication bands Bs1, Bs2, and Bs3 may be set to bands separated to some extent in consideration of the performance of the low-frequency filter units 131, 132, and 133.

<Effect>
According to the fourth embodiment described above, the following effects can be obtained in addition to the effects (1) to (6) of the above embodiment.

  (8) By using a plurality of communication bands, a transmission signal in a communication band different from the frequency of the conduction noise is detected even when the conduction noise is superimposed on the power supply line 5. Therefore, a power supply line having excellent noise immunity with a simple configuration including only a plurality of communication filters, a plurality of detection units, and a plurality of determination units without providing a large-scale signal processing circuit unlike the frequency spreading method. Communication can be realized.

(Fifth embodiment)
<Difference from Fourth Embodiment>
The fifth embodiment is different from the fourth embodiment in that a processing control unit 21 is provided in addition to the configuration of the ECU 10C according to the fourth embodiment.

  Hereinafter, the configuration of the ECU 10D according to the present embodiment will be described with reference to FIG. Here, the configuration of ECU 10D will be described assuming that composite signal Sa is transmitted from power supply line 5 from ECU 100D to ECU 10D. The ECU 100D has the same configuration as the ECU 10D.

  The ECU 10D includes a processing control unit 21 in addition to the configuration of the ECU 10C. The processing control unit 21 is connected to the signal lines that integrate the outputs Fo of the determination units 151, 152, and 153, and to the determination units 151 and 152. When any of the determination units 151, 152, and 153 determines that the target node ID and the own node ID match, the processing determination unit 21 determines the determination unit 153 corresponding to the communication band Bs3 having the highest frequency. The processing of the determination units 151 and 152 except for the above is stopped. That is, when the output Fo = 1 is transmitted from any one of the determination units 151, 152, and 153 to the power control device 11, the power supply to the determination units 151 and 152 is stopped.

  As shown in FIG. 14, the higher the transmission frequency of the transmission signal, the earlier the timing of passing through the low frequency filter unit, and it is determined at an earlier timing whether the target node ID and the own node ID match. Then, it is sufficient that the output Fo = 1 is obtained from any one of the determination units 151, 152, and 153. Therefore, when the output Fo = 1 is transmitted from any of the determination units 151, 152, and 153, there is no problem even if the processing by the determination units 151 and 152 is stopped. By stopping the processing of the determination units 151 and 152, the power consumed by the determination units 151 and 152 is reduced. Since the determination unit 153 has already completed the processing when the output Fo = 1 is transmitted from any of them, the processing control unit 21 does not stop the processing.

  As described above, by including the processing control unit 21, when the output Fo = 1 is first transmitted from the determination unit 153, the power consumed by the determination units 151 and 152 is reduced. Further, when the transmission signal Ss3 is not correctly detected by the detection unit 143 and the output Fo = 1 is first transmitted from the determination unit 152, the power consumed by the determination unit 151 is reduced.

  Further, not only the determination units 151 and 152 but also the detection units 141 and 142 may be stopped. By stopping the processing of the detection units 141 and 142, power consumption is further reduced.

  When performing one-way communication from the ECU 100D to the ECU 10D, the ECU 10D may not include the transmission units 311, 312, 313 and the frequency control units 321, 322, 323. Also, the ECU 100D may not include the low frequency filter units 131, 132, 133, the detection units 141, 142, 143, and the determination units 151, 152, 153.

<Effect>
According to the fifth embodiment described above, the following effects are obtained in addition to the effects (1) to (6) and (8) of the above embodiment.

  (9) When the output Fo = 1 is transmitted from any of the determination units, the processing of the determination units 151 and 152 corresponding to the communication bands Bs1 and Bs2 excluding the communication band Bs3 having the highest frequency is stopped. In addition, power consumption can be suppressed.

(Sixth embodiment)
<Difference from Fourth Embodiment>
In the sixth embodiment, in addition to the configuration of the ECU 10C according to the fourth embodiment, a point that a noise detection unit 22 and a band change unit 23 are provided, and the configuration of the low-frequency filter units 131E, 132E, and 133E is different from that of the It differs from the fourth embodiment in that it differs from the configuration of 131, 132, 133.

  Hereinafter, the configuration of the ECU 10E according to the present embodiment will be described with reference to FIG. Here, the configuration of the ECU 10E will be described assuming that the combined signal Sa is transmitted from the ECU 10E to the ECU 100E via the power supply line 5. The ECU 10E and the ECU 100E have the same configuration.

  The ECU 10E includes low-frequency filter units 131E, 132E, and 133E instead of the low-frequency filter units 131, 132, and 132, and further includes a noise detection unit 22 and a band change unit 23, as compared with the ECU 10C.

  Each of the low-frequency filter units 131E, 132E, and 133E includes a plurality of elements having different element values for each element constituting the BPF, and has a configuration in which an element value can be selected. That is, when the BPF has a configuration as shown in FIG. 3, the low-frequency filter units 131E, 132E, and 133E respectively include a plurality of capacitors Ch having different capacitance values, a plurality of resistors Rh having different resistance values, and a plurality of resistors having different capacitance values. , And a plurality of resistors Rl having different resistance values. The low-frequency filter units 131E, 132E, and 133E have a configuration in which one capacitor Ch, one resistor Rh, one capacitor Cl, and one resistor Rl can be selected.

  After the ignition or starter switch of the vehicle is turned on and started, the noise detection unit 22 detects the frequency of the conducted noise superimposed on the power supply line 5 before transmitting the composite signal Sa from the ECU 10E for the first time. Further, the noise detection unit 22 transmits the frequency of the conduction noise to the microcomputer 20. The microcomputer 20 transmits the frequency of the conduction noise to the ECU 100E via any one of the normal transmission paths 2 to 4.

  The band changing unit 23 changes the plurality of communication bands Bs1, Bs2, and Bs3 so as to avoid the frequency of the conduction noise detected by the noise detecting unit 22. Then, the band changing unit 23 changes the transmission frequencies fs1, fs2, fs3 by the frequency control units 321, 322, 323 in accordance with the changed communication bands Bs1, Bs2, Bs3.

  Further, the band changing unit 23 changes the pass bands Bf1, Bf2, and Bf3 of the low frequency filter units 131E, 132E, and 133E so as to avoid the frequency of the conduction noise detected by the noise detection unit 22. That is, the band changing unit 23 appropriately selects an element from a plurality of elements having different element values included in the low-frequency filter units 131E, 132E, and 133E so as to avoid the frequency of the conduction noise, and forms a BPF. The pass bands Bf1, Bf2, and Bf3 are bands that match the communication bands Bs1, Bs2, and Bs3.

  On the other hand, the band changing unit 23 of the ECU 100E also changes the communication bands Bs1, Bs2, Bs3 and the pass bands Bf1, Bf2, Bf2 according to the frequency of the conduction noise received from the ECU 10E. As a result, a composite signal Sa having components of the transmission frequencies fs1, fs2, and fs3 that avoids the frequency of the conduction noise can be superimposed on the power supply line 5 from the ECU 10E and received by the ECU 100E. Further, the ECU 10E can also receive the composite signal Sa having the components of the transmission frequencies Fs1, fs2, and fs3 that avoids the frequency of the conduction noise.

<Effect>
According to the sixth embodiment described above, the following effects are obtained in addition to the effects (1) to (6) and (8) of the above embodiment.

  (10) By changing the plurality of communication bands Bs1, Bs2, Bs3 and the plurality of pass bands Bf1, Bf2, Bf3 so as to avoid the frequency of the detected conduction noise, the superposition of the conduction noise is suppressed. Transmission of the signal Sa can be realized.

(Seventh embodiment)
<Difference from Fourth Embodiment>
The seventh embodiment is different from the fourth embodiment in that a noise detection unit 22F and output control units 331, 332, 333 are provided in addition to the configuration of the ECU 10C according to the fourth embodiment.

  Hereinafter, the configuration of the ECU 10F according to the present embodiment will be described with reference to FIG. Here, the configuration of the ECU 10F will be described on the assumption that the combined signal Sa is transmitted from the ECU 10F to the ECU 100F via the power supply line 5. The ECU 10F and the ECU 100F have the same configuration.

  The noise detection unit 22F detects the frequency of the conduction noise superimposed on the power supply line 5 after the ignition or starter switch of the vehicle is turned on and started, and before the combined signal Sa is transmitted from the ECU 10F for the first time. More specifically, the noise detection unit 22F detects which of the communication bands Bs1, Bs2, and Bs3 that has been set contains the frequency of the conducted noise. Therefore, the low-frequency filter units 131, 132, 133 and the detection units 141, 142, 143 may be used as the noise detection unit 22F, or may be separately provided.

  The output control units 331, 332, and 333 are connected to the noise detection unit 22F and the transmission units 311, 312, and 313, respectively, and output the transmission units 311, 312, and 313 according to the detection result by the noise detection unit 22F. Control. Specifically, the output control units 331, 332, and 333 amplify the amplitude of the communication signal belonging to the communication band including the frequency of the detected conduction noise. For example, when the frequency of the detected conduction noise is 10 Hz, the output control unit 331 amplifies the amplitude of the communication signal Ss1 output from the transmission unit 311. Thereby, the S / N ratio in the communication band where the conduction noise exists is improved.

  In addition, the output control units 331, 332, and 333 may reduce the amplitude of a communication signal in a communication band that does not include the frequency of the detected conduction noise. For example, when the frequency of the detected conduction noise is 10 Hz, the output control units 332 and 333 may reduce the amplitude of the communication signals Ss2 and Ss3 output from the transmission units 312 and 313. Thereby, power consumption is suppressed.

  When performing one-way communication from the ECU 10F to the ECU 100F, the ECU 100F may not include the transmission units 311, 312, 313 and the frequency control units 321, 322, 323. Further, the ECU 10F may not include the low-frequency filter units 131, 132, 133, the detection units 141, 142, 143, and the determination units 151, 152, 153. In this case, the ECU 10F needs to separately include the noise detection unit 22F.

<Effect>
According to the seventh embodiment described above, the following effects can be obtained in addition to the effects (1) to (6) and (8) of the above embodiment.

  (11) Since the amplitude of the basic signal in the communication band including the frequency of the detected conduction noise is amplified, the SN ratio of the communication band increases. This makes it possible to detect the basic signal in the communication band including the frequency of the conduction noise.

(Other embodiments)
The embodiments for carrying out the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be implemented with various modifications.

  (A) As shown in FIG. 18, the low-frequency filter units 13, 131, 132, 133, 131E, 132E, and 133E are replaced by a low-frequency filter unit 13a composed of a series resonance circuit of a capacitor Cr, a coil Lr, and a resistor Rr. It may be. The series resonance circuit is a bandpass filter that resonates at the communication frequency fs. As for the values of the respective elements, for example, the capacitance of the capacitor Cr is 1 mF, the inductance of the coil Lr is 0.25H, and the resistance value of the resistor Rr is 100Ω.

  When the low-frequency filter units 131, 132, and 133 are series resonance circuits, the values of the respective elements are, for example, the capacitance of the capacitor Cr is 2.2 nF, 0.22 μF, and 22 μF, and the inductance of the coil Lr is 0.1 H. , 0.1H, 0.1H and the resistance value of the resistor Rr are 13Ω, 1.3 kΩ, and 130Ω.

  FIG. 19 shows the frequency characteristics of the circuit impedance Z1 when the communication frequency fs is 10 Hz and the low-frequency filter unit 13 is connected in parallel with the capacitor Cp, and the circuit impedance Z4 when the low-frequency filter unit 13a is connected. . The circuit impedance Z4 has a minimum value of about 100Ω at 10 Hz which is the resonance frequency of the series resonance circuit. The circuit impedance Z4 is smaller in the low-frequency region than the circuit impedance Z1, but is large enough to allow communication. Further, the circuit impedance Z4 has a maximum value near 1 kHz at which resonance between the capacitor Cp and the series resonance circuit occurs, and the frequency characteristic is equal to the frequency characteristic of the circuit impedance Z1 in a frequency region of 1 kHz or more. This is because the circuit impedance Z4 approaches the impedance of the capacitor Cp in the high frequency region. Therefore, even when the low-frequency filter section 13a is connected in parallel to the capacitor Cp, the noise removal performance of the capacitor Cp does not decrease.

  FIG. 20 shows the filter passing characteristics of the low-frequency filter unit 13, the filter passing characteristics of the low-frequency filter unit 13a with the resistance value of 100Ω, and the filter passing characteristics of the low-frequency filter unit 13a with the resistance value of 1 kΩ. Show. The filter passing characteristic indicates the ratio of the output voltage to the input voltage of the filter, that is, the gain. In the case of the low-frequency filter section 13, a loss occurs when passing through the resistor Rl. Therefore, as shown in FIG. 20, when the low frequency filter unit 13a is used, the gain at the communication frequency fs can be higher than when the low frequency filter unit 13 is used. However, since the low-frequency filter unit 13a includes the coil Lr, it cannot be provided in an IC constituting the ECU 10. Therefore, when the low frequency filter unit 13a is connected, the physique of the ECU 10 becomes larger than when the low frequency filter unit 13 is connected.

  The pass characteristic of the low-frequency filter unit 13a is determined by the ratio of the series impedance of the capacitor Cr and the coil Lr to the impedance of the resistor Rr. Therefore, as shown in FIG. 20, when the resistance Rr is 1 kΩ, the gain is higher in a wider frequency range than when the resistance Rr is 100Ω. Therefore, it is necessary to set the resistance value of the resistor Rr so that the pass characteristic of the filter is optimized.

  (B) The HPF of the low-frequency filter units 13, 131, 132, 133, 131E, 132E, and 133E may be an AC coupling capacitor connected in series to the input side of the LPF. In this case, the value of each element of the low frequency filter unit 13 is, for example, 100 μF for the capacitance of the AC coupling capacitor, 510 kΩ for the resistance of the resistor Rl, and 0.01 μF for the capacitance of the capacitor Cl. Further, the low-frequency filter unit 13 may be composed of only the LPF.

(C) The ECU 10 may include both the transmission unit 16 and the detection unit 17.
(D) In the fourth to seventh embodiments, the number of communication bands to be set is not limited to three, but may be two or four or more. A transmission unit, a frequency control unit, a low-frequency filter unit, a detection unit, and a determination unit may be provided according to the set number of communication bands.

(E) The fourth to seventh embodiments may be implemented by combining a plurality of embodiments.
(F) Other control signals may be transmitted and received via the power supply line 5 without being limited to the command signal for turning on or off the power supply.

  (G) When each ECU connected to the in-vehicle network system 200 may execute processing based on the communication signal Ss, the communication signal Ss may not include node information. In that case, the ECU 10 may not include the determination unit 15. The power control unit 11 may control power supply when the detection unit 14 receives the communication signal Ss.

  (H) A plurality of functions of one component in the above embodiment may be realized by a plurality of components, or one function of one component may be realized by a plurality of components. . Also, a plurality of functions of a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above-described embodiment may be added to or replaced by the configuration of another above-described embodiment. In addition, all aspects included in the technical idea specified only by the language described in the claims are embodiments of the present invention.

  (I) In addition to the communication control device described above, the present invention can be realized in various forms, such as a system including the communication control device as a component, a power line communication method, and the like.

  5 Power line 10, 10A, 10B, 10C, 10D, 10E, 10F ECU, 13, 13a, 131, 132, 133, 131E, 132E, 133E Low frequency filter unit 14, 141, 142, 143 Detection unit.

Claims (14)

A communication control device (10, 10A to 10F) that communicates communication signals via a power supply line (5) that is grounded via a noise countermeasure capacitor (Cp) and supplies power to a plurality of devices. So,
A communication band of communication via the power supply line is set to at least one frequency band lower than a frequency band removed from the power supply line through the capacitor,
At least one communication filter (13, 13a, 131 to 133, 131E to 133E) including a resistance element and a reactance element, connected to the power supply line in parallel with the capacitor, and having the communication band as a pass band. )When,
At least one detection unit (14, 141 to 143) connected to a connection point between the resistance element and the reactance element and configured to detect the communication signal from an output of the communication filter. Communication control device.   The communication control device according to claim 1, wherein the communication signal includes on / off information for instructing power on or off of the communication control device.   The communication control according to claim 2, further comprising a power control unit (11) configured to control power supply in the communication control device according to the on / off information included in the communication signal detected by the detection unit. apparatus. The communication signal includes target node information for identifying a communication target,
A determination unit configured to determine whether the target node information included in the communication signal detected by the detection unit and the own node information stored in advance to identify the own device match each other; Unit (15),
The communication control device according to claim 3, wherein the power control unit is configured to receive the on / off information and control power supply in the communication control device when the determination unit determines that they match. . As a communication band of communication via the power supply line, a plurality of different communication bands are set in a frequency band lower than a frequency band removed from the power supply line through the capacitor,
As the communication filter, a plurality of communication filters having a pass band for each of the plurality of communication bands,
The communication control device according to claim 4, further comprising a plurality of detection units configured to detect the communication signal from each of the plurality of communication filters as the detection unit.   When it is determined by the determination unit corresponding to any communication band of the plurality of communication bands to match, the corresponding to the communication band excluding the highest frequency communication band of the plurality of communication bands. The communication control device according to claim 5, further comprising a processing control unit (21) configured to stop processing of the determination unit. A plurality of transmission units (311 to 313) configured to transmit the communication signals of the plurality of communication bands to another device via the power line;
A noise detection unit (22) configured to detect a noise frequency of the power supply line;
A band changing unit (23) configured to change the plurality of communication bands and the pass band of the plurality of communication filters so as to avoid the noise frequency detected by the noise detecting unit. The communication control device according to claim 5, further comprising: A plurality of transmission units (311 to 313) configured to transmit the communication signals of the plurality of communication bands to another device via the power line;
A noise detector (22F) configured to detect a noise frequency of the power supply line;
Among the communication signals of the plurality of communication bands transmitted from the plurality of transmission units, an amplitude is amplified for a communication signal of a communication band including the noise frequency detected by the noise detection unit. The communication control device according to any one of claims 5 to 7, further comprising: an output control unit (331 to 333).   The communication control device according to any one of claims 1 to 8, wherein the communication filter includes a passive element.   The communication control device according to claim 1, wherein the communication filter is a bandpass filter.   The communication control device according to claim 10, wherein the communication filter includes a series resonance circuit that causes resonance at a communication frequency of the communication signal.   The communication control device according to any one of claims 1 to 4, comprising a transmission unit (16) configured to transmit the communication signal to another device via the filter. A detection unit (17) configured to detect the input of the communication signal when a voltage value input via the communication filter changes more than a preset threshold value;
The communication according to claim 4, wherein the power supply control unit is configured to start supplying power to the detection unit and the determination unit on condition that the communication signal is detected by the detection unit. Control device. A plurality of electronic control units mounted on the vehicle are connected to the power supply line,
The communication control according to any one of claims 1 to 13, wherein the communication control device is the electronic control device, and communicates the communication signal with another electronic control device via the power supply line. apparatus.