electronic control device

Abstract

An electronic control device includes: a circuit board disposed in a housing and having a communication circuit capable of receiving or transmitting a differential signal via a pair of signal pins; a connector electrically connected to the circuit board and inputting a signal transmitted by single-end transmission from an electronic device outside the housing to the communication circuit; and a noise cancellation signal output circuit outputting a noise cancellation signal corresponding to noise superimposed on the signal in the connector, one of the pair of signal pins of the communication circuit being connected to the connector and the other being connected to the noise cancellation signal output circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to an electronic control device. BACKGROUND

[0002] In recent years, in order to drive assist systems and automatic driving, a method of transmitting sensor data by high-speed signal transmission by connecting a sensor module typified by a camera and an electronic control device by a coaxial line is increasing.

[0003] With the high speed of the signal, the resistance to external electromagnetic noise becomes one of the problems, and in particular, noise induced in the shield layer of the coaxial cable enters the electronic control device and overlaps on the signal wiring, which becomes a problem that hinders signal transmission.

[0004] In Patent Literature 1, a method is disclosed in which, in a signal transmission method using an IC that uses a transmission and reception differential signal and a coaxial line, a common mode choke coil is inserted into the signal wiring, thereby suppressing radiation from the device and external common mode noise.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Publication No. 2019-536300 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, the technology of Patent Literature 1 works in that it does not emit common mode noise of the differential wiring in the substrate to the outside and does not input common mode noise from the outside to the differential wiring, but in the case where noise transmitted in the shield layer of the coaxial line overlaps as a voltage variation between the signal wiring and the ground in the connector portion, it cannot be attenuated. Therefore, there is a problem that the noise resistance to external noise is low.

[0010] TECHNICAL MEANS FOR SOLVING THE PROBLEMS

[0011] The electronic control device of the present application has: a circuit substrate provided in a frame, having a communication circuit capable of receiving or transmitting a differential signal via a pair of signal pins; a connector electrically connected to the circuit substrate, inputting a signal transmitted by single-ended transmission from an electronic device outside the frame to the communication circuit; and a noise cancellation signal output circuit outputting a noise cancellation signal corresponding to noise overlapping on the signal in the connector, one of the pair of signal pins of the communication circuit being connected to the connector, and the other being connected to the noise cancellation signal output circuit.

[0012] EFFECTS OF THE INVENTION

[0013] According to the present application, noise resistance to external noise can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a circuit configuration diagram of the electronic control device of Embodiment 1.

[0015] Figure 2 is an explanatory diagram explaining the flow of noise of Embodiment 1.

[0016] Figure 3 is a perspective view showing the appearance of the electronic control device of Embodiment 1.

[0017] Figure 4 is Figure 3 an A-A' cross-sectional view of

[0018] Figure 5 is a diagram showing the appearance of the circuit substrate of Embodiment 1.

[0019] Figure 6 is a diagram showing the appearance of the circuit substrate of Embodiment 2.

[0020] Figure 7 is a diagram showing the substrate pattern of the noise canceling signal output circuit of Embodiment 3.

[0021] Figure 8 is a circuit configuration diagram of the electronic control device of Embodiment 4.

[0022] Figure 9 is a diagram showing the appearance of the circuit substrate of the electronic control device of Embodiment 5.

[0023] Figure 10 is a circuit configuration diagram of the electronic control device of Embodiment 6. DETAILED DESCRIPTION

[0024] Hereinafter, a preferred embodiment of the present application will be described with reference to the accompanying drawings. Note that the following description schematically shows the range required for explanation for achieving the object of the present application, mainly explains the range required for explanation of the corresponding part of the present application, and omits the part of explanation using the publicly known technology. In this example, the common mode noise is noise superimposed as a voltage variation between the signal line and the ground, and the differential mode noise is noise flowing in the shield layer of the coaxial cable. The mode conversion in the connector part means that a part of the signal wiring is exposed from the shield layer in the substrate connection part of the connector, and thus the differential mode noise of the shield layer is transferred to the signal wiring to flow as the common mode noise in the signal wiring.

[0025] In each of the embodiments described below, in a case where a signal from a signal generator (also referred to as a driver) is transmitted to a passive circuit provided on a substrate through a cable with a connector (coaxial high-speed communication cable) covered by a shield frame, common mode noise is superimposed on the signal as normal mode noise by mode conversion. By using the circuit configuration described in each of the embodiments to generate a signal that cancels the normal mode noise, the noise superimposed on the signal is removed. This is because it is most effective to remove the noise at a stage preceding a circuit that demodulates a received signal.

[0026] Thus, the signal quality of a signal transmitted in the cable is not hindered, noise resistance can be improved, and both noise resistance and performance of coaxial high-speed communication can be taken into account. In addition, a low-cost connector can also be used.

[0027] In addition, in each of the embodiments below, a signal generator is described as a camera mounted on a vehicle. Such a camera cable is a Gbps coaxial high-speed transmission, and has low noise resistance. Thus, it is difficult to ensure the reliability of a signal for autonomous driving. Furthermore, in a vehicle-mounted device, from the viewpoints of reliability and cost, there are constraints on the shield layer structure that can be adopted in the vicinity of a connector, and thus it is difficult to remove noise superimposed by mode conversion from the outside in the connector portion, but in each of the embodiments, the noise can be canceled.

[0028] <Embodiment 1>

[0029] Figure 1 is a circuit configuration diagram of the electronic control device of Embodiment 1. Figure 1 The electronic control device of the embodiment of is as follows: the primary side of a common mode choke coil is connected to a common mode noise path that penetrates from a substrate GND (SG) to a frame GND (FG), the secondary side is connected to the n pin (unused) of a receiver via a resistor, thereby generating a waveform (noise-induced voltage) close to noise superimposed on a signal in a connector, which is input to the n pin of an unused differential receiver, and canceling the normal mode noise superimposed on the signal in the connector.

[0030] Thus, noise resistance can be improved without hindering signal quality, and both noise resistance and performance of coaxial high-speed communication can be taken into account. In addition, a low-cost connector can also be used.

[0031] Hereinafter, a detailed description will be given. As shown in Figure 1 The electronic control device 101 is mounted on a vehicle and is configured with a circuit substrate 103.

[0032] The electronic control device 101 is connected to a connector 106 of a coaxial cable 104 connected to a camera 102 (CCD: also referred to as a sensor module).

[0033] Moreover, the cable-side coaxial connector 106 is combined with the board-side coaxial connector 105 of the electronic control device 101.

[0034] The circuit board 103 is provided with a signal ground 251 (SG: ground pattern) and a frame ground 252 (FG), and is further provided with a differential receiver 201 (differential amplifier), coupling capacitors 203-1, 203-2, a terminal resistor 204, a common-mode choke coil 211 (winding number: 1 to 1), a frame ground connection capacitor 206, and adjustment resistors 212-1, 212-2. The signal ground 251 (SG) is connected to the shield layer of the coaxial cable 104 via a connector ground connection 205, the board-side coaxial connector 105, and the cable-side coaxial connector 106.

[0035] The differential receiver 201 is provided with a signal input pin 307, an n pin 308 (empty pin), and the like. The differential receiver 201 is a communication circuit that can receive a differential signal via the pair of signal pins 307, 308. In the electronic control device 101, one of the signal pins 307 is used as a pin for signal input, and receives a signal transmitted from the camera 102 by single-ended transmission.

[0036] The signal line (core wire) of the coaxial cable 104 combined with the board-side coaxial connector 105 of the electronic control device 101 is connected to a signal wiring 202 on the board, and the signal wiring 202 is electrically connected to the signal input pin 307 of the differential receiver 201 via the coupling capacitor 203-1. Therefore, the signal transmitted from the camera 102 by single-ended transmission is input to the differential receiver 201 via the connector 105.

[0037] The coupling capacitor 203-2 is electrically connected to the terminal resistor 204 and the n pin 308 (empty pin).

[0038] The signal ground 251 (SG) is connected to one end of a primary coil L1 of the common-mode choke coil 211, and the other end of the primary coil L1 is connected to one end of the frame ground connection capacitor 206. The other end of the frame ground connection capacitor 206 is connected to the frame ground 252 (FG). That is, the primary coil L1 of the common-mode choke coil 211 is connected between the signal ground 251 and the frame ground 252. The frame ground 252 (FG) is connected to the ground line 250 of the vehicle body of the vehicle on which the electronic control device 101 is mounted.

[0039] One end side of the secondary coil L2 of the common mode choke coil 211 is connected to the signal ground 251 via the adjustment resistor 212-2, and the other end side is connected to the adjustment resistor 212-1 and the terminal resistor 204. The terminal resistor 204 is connected to the n pin 308 of the differential receiver 201 via the coupling capacitor 203-2. That is, the secondary coil L2 of the common mode choke coil 211 is connected to the n pin 308 of the differential receiver 201 via the voltage dividing resistor composed of the adjustment resistor 212-1 and the terminal resistor 204.

[0040] Here, in the electronic control device 101 of the present embodiment, one of the pair of coils constituting the common mode choke coil 211 is used as the primary coil L1, and the other is used as the secondary coil L2. In addition, a general common mode choke coil is composed of a pair of coils wound on a magnetic core respectively, and has the same structure as a transformer. Therefore, a transformer can be used instead of the common mode choke coil 211.

[0041] One end of each of the adjustment resistors 212-1 and 212-2 is connected to the signal ground 251 (SG). The other end of the adjustment resistor 212-1 is connected to one end of the secondary coil L2 of the common mode choke coil 211, and the other end of the adjustment resistor 212-2 is connected to the other end of the secondary coil L2 of the common mode choke coil 211.

[0042] In addition, the resistance value of the adjustment resistor 212-2 and the resistance value of the voltage dividing resistor composed of the adjustment resistor 212-1 and the terminal resistor 204 are preferably selected at the time of product development according to the mode conversion amount (frequency, voltage, current of noise) of the connector section described later. That is, according to the transfer coefficient of the mode conversion in the connector, the resistance value that can make the amplitude of the waveform input to the n pin 308 side of the differential receiver 201 and the amplitude of the noise waveform superimposed on the signal wiring substantially equal to cancel out is determined by simulation or actual equipment, and the resistance value of each resistor is adjusted accordingly.

[0043] (Action explanation of Embodiment 1)

[0044] Reference Figure 2 The operation of the device configured as described above is explained. Figure 2 is an explanatory diagram explaining the flow of noise of Embodiment 1. In Figure 2In this embodiment, a portion of the external common-mode noise is superimposed on the signal wiring 202 as constant-mode noise due to the mode shift 153 in connector 105, and is input to the signal input pin 307 of the differential receiver 201 along with the received signal, which is the same as in the existing configuration. In the electronic control device 101 of this embodiment, a waveform approximately equal to the constant-mode noise generated by the mode shift 153 is generated by inserting the common-mode choke coil 211, adjustment resistors 212-1 and 212-2 into the common-mode noise path 151. This waveform reaches the n-pin 308 of the differential receiver 201 through path 154. As a result, the noise superimposed on the signal due to the mode shift 153 in connector can be canceled within the differential receiver 201, thereby improving noise immunity. Up to a certain frequency, the delay caused by the path difference can be ignored, so the noise waveform superimposed on the signal wiring input to the signal input pin 307 and the waveform input to the n-pin 308 can be considered as in phase and can be eliminated by the differential receiver 201.

[0045] like Figure 2 As shown, when external noise A is generated outside the electronic control device 101, this external noise A flows into the shield of the coaxial cable 104, the cable-side connector 106, the board-side coaxial connector 105, etc. (common-mode noise). Since the core wire of the coaxial cable 104 is covered by the shield, the external noise A directly overlaps with the low level of the core wire, which serves as a signal line, in the coaxial cable 104. On the other hand, due to the aforementioned mode conversion 153, the external noise A overlaps with the signal wiring 202 in the connector 105, thereby generating common-mode noise.

[0046] Common-mode noise flowing from coaxial cable 104 into electronic control unit 101 via connectors 106 and 105 enters ground wire 250 via path 151 through connector ground connection 205, signal ground 251 (SG), primary side L1 of common-mode choke coil 211, rack ground connection capacitor 206, rack ground 252 (FG).

[0047] As common-mode noise flows through path 151, a voltage (noise-induced voltage) corresponding to the common-mode noise is generated on the secondary side L2 of the common-mode choke coil 211.

[0048] The noise-induced voltage generates a current flowing into the n-pin 308 of the differential receiver 201 via path 154 through signal ground 251 (SG), adjustment resistor 212-2, secondary side L2 of common-mode choke coil 211, terminating resistor 204 (also known as output resistor), and coupling capacitor 203-2.

[0049] On the other hand, the current caused by the noise-induced voltage is also shunted to the adjustment resistor 212-1, and is input to the n pin 308 of the differential receiver 201 via the terminal resistor 204 (also referred to as an output resistor), the coupling capacitor 203-2.

[0050] At this time, since one side of the adjustment resistor 212-2 is connected to the signal ground 251 (SG), the noise-induced voltage is applied to a series circuit composed of the adjustment resistor 212-2 and the secondary side L2 of the common-mode choke coil 211.

[0051] In addition, since one side of the adjustment resistor 212-1 is connected to the signal ground 251 (SG), the noise-induced voltage is also applied to the adjustment resistor 212-1.

[0052] Therefore, when extraneous common-mode noise is input to the electronic control device 101 via the shield frame of the connector 105, even if normal-mode noise is superimposed on the signal transmitted in the signal wiring 202 due to the mode change 153, and is input to the input pin 307 of the differential receiver 201 via the coupling capacitor 203-1, a noise-induced voltage of the same level and the same frequency as the normal-mode noise is input to the n pin 308 of the differential receiver 201 via the coupling capacitor 203-2. As a result, the normal-mode noise is canceled by the differential action of the differential receiver 201, and thus the influence of the extraneous common-mode noise can be removed. In addition, at this time, as described above, the common-mode choke coil 211 outputs the noise-induced voltage, and thus functions as a noise cancellation signal output circuit that outputs a noise cancellation signal for canceling the normal-mode noise.

[0053] Therefore, the signal quality from the camera 102 is not hindered, and the noise tolerance and performance of the coaxial high-speed communication can be balanced. In addition, a less expensive connector that employs a metal plate structure with a large gap in the shield structure or the like can be employed.

[0054] This circuit is composed only of passive elements, and has a reduction effect not only on constant noise such as that of an immunity evaluation test, but also on intermittent noise that is easily generated along with the electrification of automobiles. In addition, since a filter or the like for removing common-mode noise is not inserted into the signal wiring 202 or the signal ground 251, there is no increase in signal loss, and thus the maintenance of the transmissible distance can be balanced.

[0055] Figure 3 is a perspective view of the electronic control device 101 of Embodiment 1, which is surrounded by a metal frame body 111 and a cover 110 Figure 1 of the circuit board 103. The metal frame body 111 and the cover 110 are fixed by screws 112. Therefore, the metal frame body 111 and the cover 110 function as a frame that houses the circuit board 103.

[0056] In addition, a metal frame 111 and a cover 110 are provided on the side of the circuit board 103. Figure 1 The coaxial connector 105 described above is connected to the cable-side connector 106 of the coaxial cable 104. In addition, the electronic control device 101 has a non-coaxial substrate-side connector 108, and is electrically connected to the non-coaxial cable-side connector 109.

[0057] In addition, the circuit components other than these connectors are omitted from the description. Figure 4 is Figure 3 an A-A' cross-sectional view.

[0058] As shown in Figure 4 , the IC 305 and the conductive EMI gasket 306 described later are provided on the circuit board 103. The EMI gasket 306 is electrically connected to the chassis ground 252 of the housing, and is pressed by the protrusion on the inner side of the cover 110. Thus, the chassis ground 252 is electrically connected to the vehicle body ground 250 of the vehicle on which the electronic control device 101 is mounted via the EMI gasket 306 and the cover 110. Figure 1 Figure 1

[0059] Next, the case where a pattern is formed on the circuit board 103 and the circuit board 103 is configured will be described using Figure 5 . Figure 1 is a diagram showing the appearance of the circuit board 103 of Embodiment 1. Figure 5 is a diagram showing the appearance of the circuit board 103 of Embodiment 1.

[0060] In Figure 5 , the upper diagram is a plan view of the circuit board 103 of Embodiment 1, and the lower diagram is a diagram showing the wiring pattern on the back side of the circuit board 103.

[0061] As shown in Figure 5 , the pins of the substrate-side coaxial connector 105 have a signal pin 312 and connector ground pins 311 on both sides.

[0062] A pattern of the signal ground 251 having a large area is formed on the circuit board 103. The connector ground pins 311 on both sides of the substrate-side coaxial connector 105 are connected to the pattern of the signal ground 251 via the through holes 310.

[0063] The signal pin 312 of the substrate-side coaxial connector 105 is connected to the signal wiring 202. The signal wiring 202 is connected to the wiring through hole 309. The signal wiring 202 and the wiring through hole 309 are surrounded by the signal ground 251.

[0064] ​​The signal wiring 202 is connected to a pattern formed on the back side of the circuit substrate 103 via the wiring via hole 309. The pattern of the signal wiring 202 is electrically connected to the signal input pin 307 of the differential receiver 201 built in the IC 305 via the other wiring via hole 309. In addition, the pattern of the signal wiring 202 can not be formed on the back side of the circuit substrate 103 but can be formed in the inner layer.

[0065] In addition, the signal ground 251 is connected to one end of the primary coil L1 of the common mode choke coil 211 and is commonly connected to one end of the adjustment resistor 212-1 and the adjustment resistor 212-2.

[0066] Further, a pattern of a chassis ground 252 is formed in a stage subsequent to the common mode choke coil 211.

[0067] A chassis ground connection capacitor 206 is connected between the pattern of the chassis ground 252 and the other end of the primary coil L1 of the common mode choke coil 211. An EMI grommet 306 is disposed on the pattern of the chassis ground 252, and the chassis ground 252 is electrically connected to the ground wire 250 via the EMI grommet 306 as described above.

[0068] Further, the secondary coil L2 of the common mode choke coil 211 is connected to the wiring via hole 309 via the terminal resistor 204 and is connected to a pattern formed on the back side of the circuit substrate 103 via the wiring via hole 309. The pattern is electrically connected to the n pin 308 of the differential receiver 201 built in the IC 305 via the other wiring via hole 309. In addition, the pattern can not be formed on the back side of the circuit substrate 103 but can be formed in the inner layer like the pattern of the signal wiring 202.

[0069] According to the above-described embodiment 1, the following effects are exerted.

[0070] (1) The electronic control device 101 is provided with: a circuit board 103 provided inside the frame (metal frame 111 and cover 110), having a communication circuit, i.e., a differential receiver 201, capable of receiving a differential signal via a pair of signal pins 307, 308; a board-side coaxial connector 105 electrically connected to the circuit board 103, inputting a signal transmitted by single-ended transmission from an electronic device (camcorder 102) outside the frame to the differential receiver 201; and a noise cancellation signal output circuit, i.e., a common-mode choke coil 211, outputting a noise cancellation signal corresponding to noise superimposed on a signal in the board-side coaxial connector 105. One of the pair of signal pins 307, 308 of the differential receiver 201 is connected to the board-side coaxial connector 105, and the other is connected to the common-mode choke coil 211. Therefore, noise superimposed on a signal wiring 202 due to mode conversion of the board-side coaxial connector 105 can be cancelled by the differential receiver 201. Thus, noise resistance to external noise can be improved.

[0071] (2) The noise cancellation signal output circuit is constituted by the common-mode choke coil 211 or a transformer. The primary side of the common-mode choke coil 211 or the transformer is connected between a signal ground 251 connected to the board-side coaxial connector 105 and a chassis ground 252 connected to the frame, and the secondary side of the common-mode choke coil 211 or the transformer is connected to the other signal pin 308 of the differential receiver 201. Therefore, using the common-mode choke coil or the transformer, a noise cancellation signal corresponding to noise superimposed on the signal wiring 202 can be easily generated and input to the signal pin 308 of the differential receiver 201.

[0072] (3) The secondary side of the common-mode choke coil 211 or the transformer is connected to the other signal pin 308 of the differential receiver 201 via a voltage dividing resistor constituted by an adjustment resistor 212-1 and a terminal resistor 204. The resistance value of this voltage dividing resistor is adjusted so that the voltage of the noise cancellation signal input to the other signal pin 308 cancels the above-mentioned noise. Therefore, the noise cancellation signal capable of cancelling noise superimposed on the signal wiring 202 can be reliably input to the signal pin 308 of the differential receiver 201.

[0073] <Embodiment 2>

[0074] Next, the use of the circuit board 103 of Embodiment 2 will be described. Figure 6 Embodiment 2 will be described. Figure 6 Fig. 2 is a diagram showing the appearance of the circuit board 103 of Embodiment 2. In Fig. 2, the upper drawing is a plan view of the circuit board 103 in the electronic control device of Embodiment 2, and the lower drawing is a diagram showing the wiring pattern on the back side of the circuit board 103. Aspects not shown here have the same structure as in Embodiment 1. Figure 6 ​

[0075] In the circuit board 103 of the present embodiment, the difference from Embodiment 1 is that a 4-pin connector 113 capable of connecting 4 coaxial cables with one connector is used, and the size of the connector portion is reduced. The connector 113 has 4 signal pins 312 and a connector ground pin 311 corresponding to each coaxial cable, respectively. In addition, the circuit board 103 of the present embodiment has 4 ICs 305 each having a differential receiver 201 built-in, corresponding to the 4 signal pins 312 of the connector 113. In the present embodiment, an example in which 4 coaxial cables are commonly connected to the connector 113 is shown, but the number of coaxial cables commonly connected to the connector 113 is not limited to this, and can be any number.

[0076] In this case, since the foreign noise induced on any one of the coaxial lines escapes to the signal ground 251 via the ground portion provided as a common structure in the connector 113, the noise is superimposed on each of the signal pins 312 to the same extent. Therefore, the common mode choke coil 211 and the adjustment resistors 212-1 and 212-2 can be commonly disposed for each coaxial cable.

[0077] Thus, the number of components and the area on the board can be saved. That is, as shown in FIG. 6, each signal pin 312 of the connector 113 is electrically connected to the signal input pin 307 of the differential receiver 201 built-in to each IC 305 via the signal wiring 202 formed on the back side or the inner layer of the circuit board 103. In addition, each connector ground pin 311 of the connector 113 is connected to the pattern of the signal ground 251 formed around the connector 113. Figure 6

[0078] And, as shown in FIG. 6, a terminal resistor 204 is provided corresponding to each IC 305, one end of each terminal resistor 204 is commonly connected to the secondary coil L2 of the common mode choke coil 211, and the other end of each terminal resistor 204 is connected to the n pin 308 of the differential receiver 201 built-in to the corresponding IC 305, respectively. That is, the n pin 308 of the differential receiver 201 of each IC 305 is commonly connected to the common mode choke coil 211 via the terminal resistor 204. Figure 6

[0079] ​​According to Embodiment 2 described above, the circuit board 103 is provided with a plurality of differential receivers 201, and the connector 113 is provided with a plurality of signal pins 312. The plurality of signal pins 312 are respectively connected to one signal pin 307 of different differential receivers 201, and the other signal pin 308 of the plurality of differential receivers 201 is commonly connected to the common-mode choke coil 211 as the noise cancellation signal output circuit. Thus, in the electronic control device capable of commonly connecting a plurality of coaxial cables, the noise resistance to external noise can be improved, and the number of components and the board area can be suppressed.

[0080] Embodiment 3

[0081] Next, the configuration of the electronic control device according to Embodiment 3 will be described with reference to the drawings. Figure 7 Embodiment 3 of the present application will be described. Figure 7 A board pattern of the noise cancellation signal output circuit in the electronic control device according to Embodiment 3 is shown. Aspects not shown here have the same structure as Embodiment 1. Embodiment 3 differs from the above-described embodiments in that the noise cancellation signal output circuit is not realized by a separate component such as a common-mode choke coil or a transformer, but by a wiring pattern on a board.

[0082] As shown in Figure 7 , in Embodiment 3, a transformer 213 is configured by a spiral-shaped wiring pattern formed on a board. By using this transformer 213 as the noise cancellation signal output circuit instead of the common-mode choke coil 211 in Embodiment 1, an electronic control device configured by such a circuit is configured. Figure 1 The structure shown here is one example, and the number of turns or the wiring configuration can be other shapes.

[0083] According to Embodiment 3 described above, the transformer 213 is configured by a wiring pattern on a board. In this way, the component cost can be reduced.

[0084] Embodiment 4

[0085] Next, the configuration of the electronic control device according to Embodiment 4 will be described with reference to the drawings. Figure 8 Embodiment 4 of the present application will be described. Figure 8 A circuit configuration diagram of the electronic control device according to Embodiment 4 is shown. Aspects not shown here have the same structure as Embodiment 1. Embodiment 4 differs from Embodiment 1 in that a low-pass filter 214 is inserted on the secondary coil L2 side of the common-mode choke coil 211, and the noise cancellation signal output circuit is configured including the low-pass filter 214.

[0086] Further, in Embodiment 4, the low-pass filter 214 is inserted between the common mode choke coil 211 and the adjustment resistor 212-1, but can be inserted into other parts that can obtain the same effect. Further, the low-pass filter 214 is preferably constituted by an LC filter or a ferrite bead or the like.

[0087] In Embodiment 1, in a case where the corresponding frequency of the noise cancellation signal output circuit using the common mode choke coil 211 and the resistor is insufficient, or due to the difference in the wiring length of the wiring to the differential receiver 201 and the signal wiring 202, the noise on the high frequency side cannot be sufficiently cancelled, and instead, an adverse effect can be caused.

[0088] Therefore, as in Embodiment 4, the low-pass filter 214 is inserted on the secondary coil L2 side of the common mode choke coil 211, and the noise induction voltage output from the common mode choke coil 211 is caused to act only on the noise within the corresponding frequency, whereby the problem can be avoided and the noise resistance can be improved.

[0089] According to Embodiment 4 described above, the low-pass filter 214 is included in the noise cancellation signal output circuit. Thereby, the adverse effect of the noise induction voltage output from the noise cancellation signal output circuit in the high frequency region can be suppressed, and the noise resistance can be improved.

[0090] <Embodiment 5>

[0091] Use Figure 9 Embodiment 5 is described. Figure 9 An appearance of the circuit board 103 of Embodiment 5 is shown. Aspects not shown here have the same structure as Embodiment 2.

[0092] Embodiment 5 differs from Embodiment 2 in that the adjustment resistor 212-3 is respectively inserted in series on each terminal resistor 204.

[0093] In a case where the overlapping noise generation difference occurs in the 4-pin connector 113 with respect to each signal pin 312, Embodiment 5 eliminates the difference. That is, the resistance value of each adjustment resistor 212-3 is adjusted according to the difference in the amount of overlapping noise overlapped to each signal wiring 202, whereby the difference in the amount of noise of each signal pin 312 can be absorbed.

[0094] In Embodiment 5, as shown in Figure 9 in the circuit board 103, each signal pin 312 of the connector 113 is electrically connected to the signal input pin 307 of the differential receiver 201 built in each IC 305 via the signal wiring 202 formed on the back side or the inner layer of the circuit board 103. Further, each connector ground pin 311 of the connector 113 is connected to the pattern of the signal ground 251 formed around the connector 113.

[0095] Moreover, such as Figure 9 As shown, corresponding to each IC 305, a series circuit consisting of an adjustment resistor 212-3 and a terminating resistor 204 is respectively provided. One end of each series circuit is connected to the secondary coil L2 of the common-mode choke coil 211, and the other end of each series circuit is connected to the n-pin 308 of the differential receiver 201 built into the corresponding IC 305. That is, in addition to the terminating resistor 204, an adjustment resistor 212-3 is also inserted between the common-mode choke coil 211 and the n-pin 308 of the differential receiver 201 of each IC 305.

[0096] According to Embodiment 5 described above, adjustment resistors 212-3 are respectively inserted between the common-mode choke coil 211, which serves as a noise cancellation signal output circuit, and the n-pin 308 of the differential receiver 201 of each IC 305. Therefore, in an electronic control device that can connect multiple coaxial cables together, the difference in the amount of noise overlapping the signals of each coaxial cable can be suppressed, thereby equalizing the signal quality.

[0097] <Implementation Method 6>

[0098] use Figure 10 Implementation method 6 will be described. Figure 10 This is a circuit diagram showing the electronic control device 101 of Embodiment 6. Aspects not shown here have the same structure as in Embodiment 1.

[0099] The difference between Embodiment 1 and Embodiment 6 is that the differential transmitter 215 and the differential receiver 201 are arranged side by side, enabling bidirectional communication. That is, in the electronic control device 101 of Embodiment 6, the circuit board 103 has a differential receiver 201 and a differential transmitter 215, thereby providing a communication circuit capable of receiving and transmitting differential signals.

[0100] According to the opposite theorem in electromagnetism, the transformation from common-mode noise to normal-mode noise in the coaxial connector 105 on the substrate side can be suppressed, and therefore the opposite transformation from normal-mode noise to common-mode noise can also be suppressed.

[0101] Therefore, similar to the example of Embodiment 1, in addition to the expected improvement in noise tolerance to external noise, the phenomenon that a portion of the transmitted signal from the differential transmitter 215 is converted into common-mode noise when it passes through the connector 105 can also be suppressed, thus suppressing the phenomenon that is the main cause of unwanted electromagnetic radiation. Furthermore, this Embodiment 6 can also be adapted when the circuit board 103 only transmits differential signals, i.e., when it has a differential transmitter 215 but not a differential receiver 201.

[0102] <Other Embodiments>

[0103] In addition, the structure based on the example of Embodiment 1 is shown in the example of the present embodiment, but can be combined with the structures of the examples of Embodiments 1 to 5.

[0104] Although the embodiments are described in detail, they are not limited to specific embodiments, and various modifications and changes can be made within the scope of the claims.

[0105] Symbol Explanation

[0106] 101 Electronic control device

[0107] 102 Camera

[0108] 103 Circuit board

[0109] 104 Coaxial cable

[0110] 105 Board-side coaxial connector

[0111] 106 Cable-side coaxial connector

[0112] 107 Non-coaxial cable

[0113] 108 Non-coaxial board-side connector

[0114] 109 Non-coaxial cable-side connector

[0115] 110 Cover

[0116] 111 Metal frame

[0117] 201 Differential receiver

[0118] 202 Signal wiring

[0119] 203-1 Coupling capacitor

[0120] 203-2 Coupling capacitor

[0121] 204 Terminal resistor

[0122] 205 Connector ground connection

[0123] 206 Chassis ground connection capacitor

[0124] 211 Common-mode choke coil

[0125] 212-1 Adjusting resistor

[0126] 212-2 Adjusting resistor

[0127] 213 Transformer

[0128] 214 low pass filter

[0129] 215 differential transmitter

[0130] 250 ground

[0131] 251 signal ground (SG)

[0132] 252 frame ground (FG)

[0133] 305 IC

[0134] 306 EMI gasket

[0135] 307 signal input pin

[0136] 308 n pin

[0137] 309 routing via

[0138] 310 ground pattern connection via

[0139] 311 connector ground pin

[0140] 312 signal pin

Claims

1. An electronic control device, characterized by comprising: Possessing: a circuit board provided in a frame, having a communication circuit capable of receiving or transmitting a differential signal via a pair of signal pins; a connector electrically connected to the circuit board, when the pair of signal pins is a signal pin of a communication circuit capable of receiving a differential signal, the connector inputs a signal transmitted by single-ended transmission from an electronic device outside the frame to the communication circuit, or, when the pair of signal pins is a signal pin of a communication circuit capable of transmitting a differential signal, the connector inputs a signal transmitted from the communication circuit to an electronic device outside the frame by single-ended transmission; and a noise cancellation signal output circuit that outputs a noise cancellation signal corresponding to noise superimposed on the signal in the connector, one of the pair of signal pins of the communication circuit is connected to the connector, and the other is connected to the noise cancellation signal output circuit.

2. The electronic control device according to claim 1, wherein the noise cancellation signal output circuit is a common mode choke coil or a transformer, a primary side of the common mode choke coil or the transformer is connected between a signal ground connected to the connector and a rack ground connected to the frame, a secondary side of the common mode choke coil or the transformer is connected to the other signal pin of the communication circuit.

3. The electronic control device according to claim 2, wherein the secondary side of the common mode choke coil or the transformer is connected to the other signal pin of the communication circuit via a voltage dividing resistor, a resistance value of the voltage dividing resistor is adjusted so that a voltage of the noise cancellation signal input to the other signal pin cancels the noise.

4. The electronic control device according to any one of claims 1 to 3, wherein the circuit board has a plurality of the communication circuits, the connector has a plurality of connector pins, the plurality of connector pins are respectively connected to the one signal pin of different communication circuits, the other signal pins of the plurality of communication circuits are commonly connected to the noise cancellation signal output circuit.

5. The electronic control device according to claim 2 or 3, wherein the transformer is constituted by a wiring pattern on a substrate.

6. The electronic control device according to any one of claims 1 to 3, wherein the noise cancellation signal output circuit includes a low-pass filter.

7. The electronic control device according to claim 4, wherein an adjustment resistor is respectively inserted between the noise cancellation signal output circuit and the other signal pin of the plurality of communication circuits. ​

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