Electronic control device and communication system

Abstract

To provide a technique for reducing the number of power lines.SOLUTION: An electronic control device 10 according to one aspect of the present disclosure is an electronic control device that communicates with an external device via an external signal line 150, and includes an internal signal line 18 and a signal output unit 20. The internal signal line is connected to the external signal line. The signal output unit outputs a superimposed signal, in which a DC component used as power in the external device is superimposed on an AC component, which is a transmission signal, to the internal signal line.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a technique for supplying power to an external device that communicates with an electronic control device.

Background Art

[0002] A technique is known in which a transmission signal, which is an AC component, is superimposed on a power line that supplies power that is a DC component for communication. For example, Patent Document 1 below describes a technique for reducing a dedicated signal line for communication by superimposing a transmission signal on a power line.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor of the present application considered reducing the number of power lines with respect to the technique described in Patent Document 1. One aspect of the present disclosure is to provide a technique for reducing the number of power lines.

Means for Solving the Problems

[0005] An electronic control device (10, 160, 240, 280) according to one aspect of the present disclosure is an electronic control device that communicates with an external device via an external signal line (150), and includes an internal signal line (18) and a signal output unit (20, 170, 250, 290).

[0006] The internal signal line is connected to the external signal line. The signal output unit outputs a superimposed signal in which a DC component used as power in the external device is superimposed on an AC component that is a transmission signal to the internal signal line.

[0007] A communication system (1, 3, 5, 7, 9) according to another aspect of the present disclosure includes an electronic control device (10, 160, 240, 280) and an external device (100, 180, 210, 260, 300) configured to communicate with the electronic control device via an external signal line (150).

[0008] The electronic control device includes an internal signal line (18) and a signal output unit (20, 170, 250, 290). The internal signal line is connected to the external signal line. The signal output unit outputs a superimposed signal in which a DC component used as power in the external device is superimposed on an AC component that is a transmission signal to the internal signal line.

[0009] The external device includes a power acquisition unit (110, 190, 220, 270) and a signal acquisition unit (140). The power acquisition unit acquires the DC component. The signal acquisition unit acquires the AC component. In this way, by superimposing the DC component used as power in the external device on the AC component that is the transmission signal, the number of power lines can be reduced.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. [1. First embodiment] [1-1.Configuration] 1 is mounted on, for example, a vehicle, and includes an electronic control unit 10 and an external device 100. Hereinafter, the electronic control unit may also be referred to as an ECU. The external device 100 is, for example, an actuator or a sensor of the vehicle, and is installed outside the ECU 10.

[0012] The ECU 10 and the external device 100 communicate bidirectionally by differential transmission via an external signal line 150. As the external signal line 150, a parallel line or a twisted pair line or the like is used. The ECU 10 includes a signal output unit 20 and a signal acquisition unit 50. The power A supplied from the power supply 2 to the ECU 10 is filtered by a filter 12 and a capacitor 14 to remove noise.

[0013] The signal output section 20 includes a buffer 22, an inverter 24, two pairs of an N-type FET 26 and a P-type FET 28, a constant current circuit 30, a capacitor 32, and a resistor 40. Two sets of buffer 22 and inverter 24 generate a normal signal B2 and an inverted signal −B2, respectively, from a transmission signal B1, which is an AC component generated by a signal generating unit (not shown). One set of N-type FET 26 and P-type FET 28 is connected at the gate side and the drain side, respectively.

[0014] Each pair of N-type FET 26 and P-type FET 28 outputs an inverted signal or a normal signal from the drain side. A constant current circuit 30 is connected to the source sides of N-type FET 26 and P-type FET 28.

[0015] The impedance of one pair of N-type FET 26 and P-type FET 28 as seen from the external signal line 150 is higher than that of a circuit configuration in which a normal signal and an inverted signal of the transmission signal B1 are output from the source side of one N-type FET 26, as in the second embodiment described later.

[0016] The direct current component of the non-inverted signal and the inverted signal of the transmission signal B1 output from the drains of the N-type FET 26 and the P-type FET 28 is removed by the capacitor 32. The power supplied from the power supply 2 to the external device 100 has noise removed by the filter 12 and the capacitor 16, passes through the resistor 40, and is superimposed on the normal signal and the inverted signal, which are AC components on the output side of the capacitor 32, in the internal signal line 18 of the ECU 10. Then, a superimposed signal in which power, which is a DC component, is superimposed on the normal signal and the inverted signal, which are AC components, is output to the internal signal line 18.

[0017] The resistors 40 are connected in parallel between the internal signal line 18 and the power supply 2 for impedance matching purposes, which equalize the impedance of the external signal line 150 and the impedance on the ECU 10 side. When the differential impedance of the external signal line 150 is Z, the resistance value of each of the resistors 40 is set to Z / 2.

[0018] The signal acquisition section 50 includes a differential amplifier 52 and a signal removal circuit 54 . The differential amplifier 52 outputs a differential signal from the combined signals -D1 and D1 of the inverted and normal signals output from the ECU 10 and the external device 100, respectively, which are combined on the external signal line 150 that performs differential transmission. In FIG. 1, -D1=-D2, and D1=D2.

[0019] This removes noise that gets mixed into the external signal line 150. The signal removal circuit 54 removes the transmission signal B1 of the device itself from the differential signal output from the differential amplifier 52. As a result, the ECU 10 obtains a received signal B3 from which the transmission signal B1 of the ECU 10 itself has been removed from the composite signals -D1, D1 of the inverted signal and the normal signal output from the ECU 10 and the external device 100. The received signal B3 is the transmission signal C1 transmitted by the external device 100, as will be described later.

[0020] The external device 100 includes a power acquisition unit 110, a signal output unit 120, a signal acquisition unit 140, and the like. The power acquisition unit 110 includes a resistor 112 and a capacitor 114. The resistor 112 is connected in parallel between each of the internal signal lines 102 connected to the external signal lines 150 and the power acquisition side of the external device 100 for impedance matching to equalize the impedance of the external signal lines 150 and the impedance on the external device 100 side. When the differential impedance of the external signal lines 150 is Z, the resistance value of each of the resistors 112 is set to Z / 2.

[0021] The capacitor 114 removes the AC component from the power passing through the resistor 112 from the internal signal line 102 and supplies power to the inside of the external device 100. The signal output unit 120 of the external device 100 has substantially the same configuration as the signal output unit 20 of the ECU 10.

[0022] The buffer 122 and the inverter 124 correspond to the buffer 22 and the inverter 24, the N-type FET 126 and the P-type FET 128 correspond to the N-type FET 26 and the P-type FET 28, the constant current circuit 130 corresponds to the constant current circuit 30, and the capacitor 132 corresponds to the capacitor 32.

[0023] The signal acquisition unit 140 of the external device 100 has substantially the same configuration as the signal acquisition unit 50 of the ECU 10 and includes a differential amplifier 142 and a signal removal circuit 144. The external device 100 outputs a differential signal from the combined signals -D2 and D2 of the inverted signal and the forward signal output from the external device 100 and the ECU 10, respectively. As described above, -D2 = -D1 and D2 = D1.

[0024] The external device 100 acquires a received signal C3 from which its own transmission signal C1 has been removed from the combined signals -D2 and D2 of the inverted signal and the forward signal output from the external device 100 and the ECU 10, respectively. The received signal C3 is the transmission signal B1 transmitted by the ECU 10, as will be described later.

[0025] [1-2. Operation] 2, a buffer 22 and an inverter 24 generate a normal signal B2 and an inverted signal −B2 from a transmission signal B1 generated by a signal generating unit (not shown) of the ECU 10. The reference potential of the transmission signal B1 and the normal signal B2 and inverted signal −B2 of the transmission signal B1 that has passed through the buffer 22 and the inverter 24 are equal at 2.5 V.

[0026] Then, the superimposed signals obtained by superimposing the power, which is a DC component that has passed through the resistor 40, on the normal signal B2 and the inverted signal −B2 in the internal signal line 18 are output to the external signal line 150.

[0027] Similarly, the buffer 122 and the inverter 124 generate a non-inverted signal C2 and an inverted signal −C2 from the transmission signal C1 generated by a signal generating unit (not shown) of the external device 100. The transmission signal C1, the non-inverted signal C2 and the inverted signal −C2 of the transmission signal C1 that has passed through the buffer 122 and the inverter 124, all have the same reference potential of 1.5 V.

[0028] Then, superimposed signals obtained by superimposing power, which is a DC component that has passed through the resistor 112, on the non-inverted signal C2 and the inverted signal −C2 in the internal signal line 102 are output to the external signal line 150.

[0029] As the power of the power supply 2 passes through the impedance matching resistor 40, the potential A of the power supply 2 superimposed on the normal signal B2 and the inverted signal −B2, which are the transmission signals, drops from 5V to 4V, for example.

[0030] Furthermore, the potential E supplied from the ECU 10 to the external device 100 passes through the resistor 112 of the external device 100, and is reduced from 4V to 3V, for example. Then, the superimposed signals, in which a voltage of 4 V is superimposed on each of the normal signal B2 and the inverted signal -B2, and the normal signal C2 and the inverted signal -C2 are combined on the external signal line 150 to become the combined signals -D1, -D2, D1, and D2 shown in Figure 2. As mentioned above, D1 = D2 and -D1 = -D2.

[0031] D1, D2, -D1, -D2, B1, C1, B2, and C2 have the relationships shown in the following equations (1) and (2) from the configuration of the circuit described above. D1 = D2 = (B2 + C2) / 2 = (B1 + C1) / 2 ···(1) -D1 = -D2 = (-B2 - C2) / 2 = (-B1 - C1) / 2 ···(2) And the received signal B3 received by the ECU10 is represented by the following equation (3) by the function of the signal acquisition unit 50.

[0032] B3 = D1 - (-D1) - B1 = 2×D1 - B1 = 2×((B1 + C1) / 2) - B1 = C1 ···(3) Similarly, the received signal C3 received by the external device 100 is represented by the following equation (4) by the function of the signal acquisition unit 140.

[0033] C3 = D2 - (-D2) - C1 = 2×D2 - C1 = 2×((B1 + C1) / 2) - C1 = B1 ···(4) As shown in equation (3), the received signal B3 received by the ECU10 is the transmission signal C1 transmitted by the external device 100 which is the counterpart device for the ECU10.

[0034] Also, as shown in equation (4), the received signal C3 received by the external device 100 is the transmission signal B1 transmitted by the ECU10 which is the counterpart device for the external device 100. In the first embodiment described above, the signal output unit 20 corresponds to the first signal output unit, the signal acquisition unit 50 corresponds to the first signal acquisition unit, the signal output unit 120 corresponds to the second signal output unit, and the signal acquisition unit 140 corresponds to the second signal acquisition unit.

[0035] [1-3. Effects] According to the first embodiment described above, the following effects can be obtained. (1a) By superimposing the DC component used as power in the external device 100 on the AC component that is the transmission signal transmitted to the external device 100 in the ECU 10, the number of power lines can be reduced.

[0036] (1b) Differential transmission is performed between the ECU 10 and the external device 100 via a pair of external signal lines 150 with equal impedance. This reduces noise generation and enables communication with noise removed, compared to superimposing transmission signals of opposite phases on a power line and a ground line with different impedances.

[0037] (1c) In the ECU 10, impedance matching is performed by a resistor 40 installed in parallel between the internal signal line 18 and the power supply 2, and in the external device 100, by a resistor 112 installed in parallel between the internal signal line 102 and the power acquisition side.

[0038] This allows highly accurate impedance matching between the external signal line 150, the ECU 10, and the external device 100, thereby reducing the occurrence of noise and communication errors due to signal reflection and the like.

[0039] (1d) In the ECU 10, the power of the power supply 2 is supplied to the external device 100 via the resistor 40, not via the N-type FET 26 and the P-type FET 28, so that the voltage drop of the power supplied from the power supply 2 can be minimized.

[0040] [2. Second Embodiment] [2-1. Differences from the first embodiment] The second embodiment has the same basic configuration as the first embodiment, so differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and reference will be made to the preceding description.

[0041] In the above-described first embodiment, the power of the power supply 2 was supplied to the external device 100 via the resistor 40. In contrast, in the second embodiment, as shown in FIG. 3, the power of the power supply 2 is supplied to the external device 100 via the N-type FET 26 and the resistor 40, which is different from the first embodiment.

[0042] Also, in the first embodiment, the transmission signals of the ECU 10 or the external device 100 were output from the drain sides of the respective N-type FETs 26 and 126 and P-type FETs 28 and 128 of the ECU 10 and the external device 100. In contrast, in the second embodiment, the transmission signal of the ECU 10 is output from the source sides of the N-type FET 26 of the ECU 160 and the P-type FET 128 of the external device 180, which is different from the first embodiment.

[0043] Also, in the first embodiment, the power acquisition unit 110 of the external device 100 includes a resistor 112 and a capacitor 114. In contrast, in the second embodiment, the power acquisition unit 190 of the external device 180 includes a coil 192 and a capacitor 114, which is different from the first embodiment.

[0044] The ECU 160 includes a signal output unit 170, a signal acquisition unit 50, and the like. The external device 180 includes a power acquisition unit 190, a signal output unit 200, a signal acquisition unit 140, and the like. The signal output unit 170 of the ECU 160 and the signal output unit 200 of the external device 180 have substantially the same configuration.

[0045] In the signal output unit 170 of the ECU 160, the source side of the N-type FET 26 and the impedance matching resistor 40 are connected in series. Through the buffer 22 or the inverter 24, the forward signal B2 and the inverted signal -B2 of the transmission signal B1 generated by a signal generation unit (not shown) of the ECU 160 are output from the source side of the N-type FET 26. DC power as a DC component is supplied to the drain side of the N-type FET 26 from the power supply 2.

[0046] The forward signal B2 and the inverted signal -B2, in which the DC power as a DC component is superimposed on the transmission signal B1 as an AC component, pass through the resistor 40 and are output from the internal signal line 18 to the external signal line 150. In the external device 180, a normal signal C2 and an inverted signal −C2, which are obtained by superimposing power, which is a DC component supplied from the ECU 160, on a transmission signal C1, which is an AC component, pass through a resistor 112 and are output from the internal signal line 102 to the external signal line 150 as superimposed signals.

[0047] The power acquisition unit 190 of the external device 180 includes a coil 192 and a capacitor 114. By using the coil 192 instead of the resistor 112 of the first embodiment, the voltage drop of the power acquired from the internal signal line 102 is reduced.

[0048] [2-2. Operation] In ECU 160, a non-inverted signal B2 and an inverted signal −B2 are output as superimposed signals, in which power, which is a DC component, is superimposed on a transmission signal B1 of ECU 160 from power supply 2 by N-type FET 26. Due to constant current circuit 30 connected to the source side of N-type FET 26, the potentials of the DC components of non-inverted signal B2 and inverted signal −B2 at the output side of N-type FET 26 are higher than the potential of transmission signal B1.

[0049] As a result, as shown in FIG. 4, the reference potential of the non-inverted signal B2 and the inverted signal −B2 of the transmission signal B1 output from each N-type FET 26 rises from 2.5V of the transmission signal B1 to 4V.

[0050] Then, the normal signal B2 and the inverted signal −B2 pass through the resistor 40 and are output from the internal signal line 18 to the external signal line 150. In the external device 180, the power, which is a DC component supplied from the ECU 160, is superimposed on the transmission signal C1 of the external device 180 by the P-type FET 128, to produce a non-inverted signal C2 and an inverted signal −C2, which are output as superimposed signals. Due to the constant current circuit 130 connected to the source side of the P-type FET 128, the reference potentials of the non-inverted signal C2 and the inverted signal −C2 at the output side of the P-type FET 128 are increased above the reference potential of the transmission signal C1.

[0051] As a result, as shown in FIG. 4, the reference potential of the non-inverted signal C2 and the inverted signal −C2 of the transmission signal C1 output from each P-type FET 128 rises from 1.5V of the transmission signal C1 to 2.5V.

[0052] Then, the normal signal C2 and the inverted signal −C2 pass through the resistor 112 and are output from the internal signal line 102 to the external signal line 150. The normal signal B2 and the inverted signal -B2, and the normal signal C2 and the inverted signal -C2 are combined on the external signal line 150 to produce combined signals D1, D2, -D1, and -D2 shown in Figure 4. D1 = D2, and -D1 = -D2.

[0053] The reception signal B3 received by the ECU 160 and the reception signal C3 received by the external device 180 are calculated from the equations (1) to (4) in the same manner as in the first embodiment. In the second embodiment described above, the signal output section 170 corresponds to the first signal output section, and the signal output section 200 corresponds to the second signal output section.

[0054] [2-3. Effects] According to the second embodiment described above, in addition to the effects (1a) and (1b) of the first embodiment described above, which are the same as those obtained by replacing ECU 10 with ECU 160 and external device 100 with external device 180, the following effects can be obtained.

[0055] (2a) The power acquisition unit 190 of the external device 180 acquires the power supplied from the ECU 160 via the coil 192, which has a resistance value lower than that of the resistor 112, so that the voltage drop caused by the power acquisition unit 190 can be reduced.

[0056] 3. Third Embodiment [3-1. Differences from the second embodiment] The third embodiment has the same basic configuration as the second embodiment, and therefore the differences will be described below. Note that the same reference numerals as those in the second embodiment indicate the same configuration, and reference will be made to the preceding description.

[0057] In the second embodiment described above, the power acquisition unit 190 of the external device 180 includes the capacitor 114 and the coil 192. In contrast, in the third embodiment, as shown in FIG. 5 , the power acquisition unit 220 of the external device 210 differs from the second embodiment in that it includes the capacitor 114 and the constant current circuit 130.

[0058] In the second embodiment, the external device 180 acquires power from the ECU 160 via the coil 192 of the power acquisition unit 190. In contrast, the third embodiment differs from the second embodiment in that the external device 210 acquires power from the ECU 160 via a resistor 112 for impedance matching of the external device 210.

[0059] In this way, the external device 210 obtains power from the ECU 160 via the impedance matching resistor 112 of the external device 210, and therefore, as shown in FIG. 6, the potential of the power E supplied to the external device 210 from the ECU 160 drops from 3 V in the second embodiment to 2 V.

[0060] Therefore, the configuration of the external device 210 of the third embodiment is suitable for external devices such as sensors with low power consumption. The reception signal B3 received by the ECU 160 and the reception signal C3 received by the external device 210 are calculated from the equations (1) to (4) in the same manner as in the first embodiment.

[0061] In the third embodiment described above, the signal output section 230 corresponds to the second signal output section. [3-2. Effects] According to the third embodiment described above, in addition to the effects (1a) and (1b) of the first embodiment described above, which are the same as those obtained by replacing ECU 10 with ECU 160 and external device 100 with external device 210, the following effects can be obtained.

[0062] (3a) Compared to the power acquisition unit 190 of the external device 180 of the second embodiment, the power acquisition unit 220 of the external device 210 does not include the coil 192, so the external device 180 can be made smaller. [4. Fourth Embodiment] [Differences from the First Embodiment] Since the basic configuration of the fourth embodiment is the same as that of the first embodiment, the differences will be described below. The same reference numerals as those in the first embodiment denote the same configurations, and reference is made to the previous description.

[0063] In the signal output unit 20 of the first embodiment described above, the power of the power supply 2, which is a DC component, is superimposed on the forward signal B2 and the inverted signal -B2 of the transmission signal B1, which is an AC component, via the impedance matching resistor 40. On the other hand, in the signal output unit 250 of the fourth embodiment shown in FIG. 7, the power of the power supply 2, which is a DC component, is superimposed on the forward signal B2 and the inverted signal -B2 of the transmission signal B1, which is an AC component, via the coil 252, which is different from the first embodiment.

[0064] Also, in the first embodiment, the external device 100 obtains power from the ECU 10 via the impedance matching resistor 112. On the other hand, in the fourth embodiment, the external device 260 obtains power from the ECU 240 via the coil 192, which is different from the second embodiment.

[0065] The received signal B3 received by the ECU 240 and the received signal C3 received by the external device 260 are obtained from equations (1) to (4) in the same manner as in the first embodiment. In the fourth embodiment described above, the signal output unit 250 corresponds to the first signal output unit.

[0066] [4-2. Effects] According to the fourth embodiment described above, in addition to the same effects as those obtained by replacing the ECU 10 with the ECU 240 and the external device 100 with the external device 260 in the effects (1a) to (1c) of the first embodiment described above, the following effects can be obtained.

[0067] (4a) In the ECU 240, the power of the power supply 2 is supplied to the external device 260 via the coil 252, not via the N-type FET 26 and the P-type FET 28, so that it is possible to minimize a voltage drop in the power supplied from the power supply 2. Therefore, this configuration is suitable for supplying power to the external device 260 that consumes a large amount of power.

[0068] [5. Fifth Embodiment] [5-1. Differences from the second embodiment] The fifth embodiment has the same basic configuration as the second embodiment, and therefore the differences will be described below. Note that the same reference numerals as those in the second embodiment indicate the same configuration, and reference is made to the preceding description.

[0069] In the signal output unit 170 of the ECU 160 of the second embodiment described above, power is supplied to the external device 180 via the impedance matching resistor 40. In contrast, a signal output unit 290 of an ECU 280 of the fifth embodiment shown in Fig. 8 differs from the second embodiment in that power is supplied to the external device 300 via a coil 252 instead of the impedance matching resistor 40.

[0070] In the second embodiment, the signal output unit 200 of the external device 180 outputs the transmission signal C1 via the P-type FET 128 having a source connected to the constant current circuit 130. In contrast, the fifth embodiment differs from the second embodiment in that the signal output unit 320 of the external device 300 outputs the transmission signal C1 via the N-type FET 126 having a source connected to the constant current circuit 130.

[0071] The reception signal B3 received by the ECU 280 and the reception signal C3 received by the external device 300 are calculated from the equations (1) to (4) in the same manner as in the first embodiment. In the fifth embodiment described above, the signal output section 290 corresponds to the first signal output section, and the signal output section 310 corresponds to the second signal output section.

[0072] [5-2.Effects] According to the fifth embodiment described above, in addition to the effects (1a) and (1b) of the first embodiment described above, which are the same as those obtained by replacing ECU 10 with ECU 160 and external device 100 with external device 300, the following effects can be obtained.

[0073] (5a) Since the ECU 280 supplies power to the external device 300 via the coil 252 instead of the impedance matching resistor 40, it is possible to reduce a voltage drop in the power supplied from the ECU 280 to the external device 300. Therefore, this configuration is suitable for supplying power to the external device 300 that consumes a large amount of power.

[0074] 6. Other Embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0075] (6a) In the above-described embodiments, the communication systems 1, 3, 5, 7, and 9 are described as performing differential transmission, but the present invention is not limited to this. Single-ended transmission may be used instead of differential transmission.

[0076] (6b) The circuits of the communication systems 1, 3, 5, 7, and 9 shown in the above-described embodiments are merely examples, and the present invention is not limited to these circuit configurations. (6c) Multiple functions possessed by one component in the above-described embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above-described embodiments may be omitted. Also, at least part of the configuration of the above-described embodiments may be added to or substituted for the configuration of another of the above-described embodiments.

[0077] (6d) In addition to the ECU and communication system described above, the present disclosure can also be realized in various forms, such as a communication method. [Explanation of symbols]

[0078] 1, 3, 5, 7, 9: communication system, 10, 160, 240, 280: ECU (electronic control unit), 18: internal signal line, 20, 170, 250, 290: signal output unit (first signal output unit), 40, 112: impedance matching resistor, 60: signal acquisition unit (first signal acquisition unit), 100, 180, 210, 260, 300: external device, 110, 190, 220, 270: power acquisition unit, 120, 200, 230, 310: signal output unit (second signal output unit), 140: signal acquisition unit (second signal acquisition unit), 150: external signal line, 192: coil

Claims

1. An electronic control device (10, 160, 240, 280) that communicates with an external device (100, 180, 210, 260, 300) via an external signal line (150), an internal signal line (18) configured to be connected to the external signal line, a signal output unit (20, 170, 250, 290) configured to output a superimposed signal obtained by superimposing a DC component used as power in the external device on an AC component that is a transmission signal to the internal signal line, The electronic control device comprising the above.

2. The electronic control device according to claim 1, wherein the signal output unit is configured to generate the AC component for differential transmission, The electronic control device.

3. The electronic control device according to claim 1 or 2, wherein the signal output unit (20) includes a resistor that matches the impedance of the electronic control device to the impedance of the external signal line, and is configured to superimpose the DC component on the AC component via the resistor, The electronic control device.

4. An electronic control device (10, 160, 240, 280), an external device (100, 180, 210, 260, 300) configured to communicate with the electronic control device via an external signal line (150), A communication system (1, 3, 5, 7, 9) comprising: wherein the electronic control device, an internal signal line (18) configured to be connected to the external signal line, a signal output unit (20, **********) configured to output a superimposed signal obtained by superimposing a DC component used as power in the external device on an AC component that is a transmission signal to the internal signal line, Comprising, the external device, a power acquisition unit (110, 190, 220, 270) configured to acquire the DC component, a signal acquisition unit (140) configured to acquire the AC component, Comprising, The communication system.

5. The communication system according to claim 4, wherein the power acquisition unit includes a coil (192) configured to acquire the DC component from the superimposed signal, The communication system.

6. The communication system according to claim 4, wherein the power acquisition unit includes a constant current circuit (130) configured to acquire the DC component from the superimposed signal, The communication system.

7. The communication system according to claim 5 or 6, When the signal output unit is a first signal output unit, the external device includes a second signal output unit (120, 200, 230, 310) configured to output the AC component that is the transmission signal. When the signal acquisition unit is a second signal acquisition unit, the electronic control device includes a first signal acquisition unit (60) configured to acquire the AC component output by the second signal output unit. The electronic control device and the external device communicate bidirectionally via the external signal line by means of the first signal output unit, the second signal output unit, the first signal acquisition unit, and the second signal acquisition unit. The first signal acquisition unit and the second signal acquisition unit are each configured to acquire the AC component transmitted by the other device by subtracting the AC component transmitted by its own device from the signal on the external signal line. Communication system.

Images