Transmission device for a differential bus system

Abstract

The invention relates to a transmission device for a differential bus system, having a first bus connection and a second bus connection for connecting to a transmission medium of the differential bus system, for example to a differential bus line, and having a transmitting device which can be connected to the first bus connection and / or to the second bus connection, and further having an impedance matching circuit which is designed to influence the impedance at the first bus connection and / or at the second bus connection.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a transmission device for a differential bus system.

[0002] The present disclosure also relates to a method for operating a transmission device for a differential bus system. SUMMARY

[0003] Exemplary embodiments relate to a transmission device for a differential bus system, the transmission device having a first bus connection and a second bus connection for connecting to a transmission medium of the differential bus system, for example to a differential bus line, and having a transmitting device which can be connected to the first bus connection and / or to the second bus connection, and further having an impedance matching circuit which is configured to influence an impedance at the first bus connection and / or at the second bus connection. This makes it possible in some embodiments to at least temporarily reduce the electromagnetic radiation of the transmission device and / or to achieve a higher immunity.

[0004] In further exemplary embodiments it is provided that the impedance matching circuit is configured to influence the impedance at the first bus connection ("first impedance") and / or the impedance at the second bus connection ("second impedance") in such a way that the impedance at the first bus connection deviates from the impedance at the second bus connection by at most a predetermined difference. This can be the case in further exemplary embodiments, for example, for at least one predetermined frequency range, i.e. for example for a partial range of the overall frequency range used by the bus system, but in other exemplary embodiments, for example, for all frequency ranges used by the bus system.

[0005] In further exemplary embodiments, the respective impedance can have a complex value at least temporarily, i.e. without vanishing imaginary part. Correspondingly, in further exemplary embodiments, the aforementioned difference can also be complex. In further exemplary embodiments, the predetermined difference can also be purely real or purely imaginary.

[0006] In further exemplary embodiments it is provided that the impedance matching circuit has at least one active semiconductor element, which in further exemplary embodiments makes it possible to achieve a particularly effective and / or precise adjustment of the first and / or second impedance.

[0007] In further exemplary embodiments it is provided that the impedance matching circuit has a first active semiconductor element and a second active semiconductor element, wherein the first active semiconductor element can be connected to the first bus connection and / or to the first transmitting device, and wherein the second active semiconductor element can be connected to the second bus connection and / or to the second transmitting device.

[0008] In a further exemplary embodiment it is provided that the impedance matching circuit has at least one circuit component which is a simulation of at least one part of the transmitting device.

[0009] In a further exemplary embodiment it is provided that the "simulation of at least one part of the transmitting device" refers to a circuit component which has the same component type (e.g. with the same component parameters or component values, e.g. except for a predetermined tolerance) in the same topology as the relevant, e.g. simulated, part of the transmitting device.

[0010] In a further exemplary embodiment it is provided that the impedance matching circuit has at least one circuit component which is a complete simulation of the transmitting device.

[0011] In a further exemplary embodiment it is provided that the at least one circuit component has a series circuit consisting of a first diode and a first transistor and a second transistor. In a further exemplary embodiment the first transistor and / or the second transistor is / are respectively configured as a field effect transistor, e.g. of the NMOS (n-channel MOSFET) or PMOS (p-channel MOSFET) type, or as a corresponding "high-voltage" variant of an n-channel MOSFET or a p-channel MOSFET.

[0012] In a further exemplary embodiment it is provided that the first diode of the at least one circuit component corresponds to the first diode of the at least one part of the transmitting device, e.g. to a type of the first diode of the at least one part of the transmitting device.

[0013] In a further exemplary embodiment it is provided that the first transistor of the at least one circuit component corresponds to the first transistor of the at least one part of the transmitting device, e.g. to a type of the first transistor of the at least one part of the transmitting device.

[0014] In a further exemplary embodiment it is provided that the second transistor of the at least one circuit component corresponds to the second transistor of the at least one part of the transmitting device, e.g. to a type of the second transistor of the at least one part of the transmitting device.

[0015] In a further exemplary embodiment it is provided that the transmitting device has a receiving device, so that the transmitting device can e.g. at least temporarily function as a transmitting and receiving device ("transceiver"). The principle advantageously achieves a lower electromagnetic radiation, e.g. during reception of a signal by the optional receiving device, in accordance with the described embodiments.

[0016] In a further exemplary embodiment it is provided that the bus system has one of the following types: CAN (Controller Area Network), CAN-FD (CAN Flexible Data Rate), CAN-FD-SIC (CAN-FD Signal Improvement Capability), CAN-XL (CAN Extra Large), LVDS (Low Voltage Differential Signaling), 10BASE-T1S.

[0017] A further exemplary embodiment relates to a method for operating a transmission device for a differential bus system, the transmission device having a first bus connection and a second bus connection for connecting to a transmission medium of the differential bus system, for example to a differential bus line, and having a transmitting device which can be connected to the first bus connection and / or to the second bus connection, wherein the transmission device has an impedance matching circuit, wherein the method has: adjusting the impedance at the first bus connection and / or at the second bus connection.

[0018] In a further exemplary embodiment it is provided that the method and / or the transmission device associated with the method has one or more of the aspects explained previously with regard to the exemplary embodiments of the transmission device.

[0019] A further exemplary embodiment relates to the application of the transmission device according to the embodiments and / or the method according to the embodiments for at least one of the following elements: a) adjusting the impedance (for example the first impedance and / or the second impedance) at at least the first and / or the second bus connection, b) adapting the first impedance at the first bus connection to the second impedance at the second bus connection, for example up to a predetermined difference, and / or vice versa, c) reducing electromagnetic radiation, for example when receiving a signal by means of the transmission device, d) reducing errors or increasing efficiency, for example during an arbitration phase in a bus system configured as CAN-XL. BRIEF DESCRIPTION OF DRAWINGS

[0020] A further exemplary embodiment results from the following description and the drawings.

[0021] Figure 1 A simplified block diagram according to an exemplary embodiment is schematically shown;

[0022] Figure 2 A simplified block diagram according to a further exemplary embodiment is schematically shown;

[0023] Figure 3 A simplified circuit diagram according to a further exemplary embodiment is schematically shown;

[0024] Figure 4 schematically illustrates a simplified circuit diagram according to a further exemplary embodiment;

[0025] Figure 5 schematically illustrates a simplified flow chart according to a further exemplary embodiment; and

[0026] Figure 6 schematically illustrates some aspects of an application according to a further exemplary embodiment. DETAILED DESCRIPTION

[0027] Figure 1 schematically illustrates a simplified block diagram of a differential bus system 10 for transmitting signals, which can be used, for example, in technical products, such as vehicles, in particular motor vehicles, production technology devices, etc.

[0028] The exemplary embodiments relate to a transmission device 100 for a differential bus system 10. The transmission device 100 has a first bus connection 101 and a second bus connection 102 for connecting to a transmission medium 12, for example to a differential bus line 12a, 12b, of the differential bus system 10, and a transmitter 110, which can be connected to the first bus connection 101 and / or to the second bus connection 102.

[0029] Furthermore, the transmission device 100 has an impedance matching circuit 120, which is configured to influence an impedance at the first bus connection 101 and / or at the second bus connection 102. This makes it possible, in some embodiments, to at least temporarily reduce the electromagnetic radiation of the transmission device 100.

[0030] In a further advantageous embodiment, it is provided that the impedance matching circuit 120 is configured to influence the impedance at the first bus connection 101 ("first impedance Z1") and / or the impedance at the second bus connection 102 ("second impedance Z2") in such a way that the impedance Z1 at the first bus connection 101 deviates from the impedance Z2 at the second bus connection 102 by at most a predetermined difference.

[0031] In a further advantageous embodiment, this can be the case, for example, for at least one predetermined frequency range, i.e. for example for a partial range of the entire frequency range used by the bus system 10 for signal transmission, but in other exemplary embodiments, for example, also for the entire frequency range used by the bus system 10.

[0032] In a further advantageous embodiment, the corresponding impedances Z1, Z2 may, for example, at least temporarily, have complex values, i.e., without a vanishing imaginary part. Correspondingly, in a further exemplary embodiment, the aforementioned difference may also be, for example, a complex value. In a further exemplary embodiment, the predetermined difference may, for example, be purely real or purely imaginary, at least temporarily.

[0033] In a further advantageous embodiment, the impedance matching circuit 120 is provided to have at least one active semiconductor element 122, which, in a further exemplary embodiment, enables particularly effective and / or precise adjustment of the first and / or second impedances Z1, Z2.

[0034] In a further exemplary embodiment, the transmission device 100 is provided with an optional receiving device 130 for receiving signals transmitted through the bus system, thereby enabling the transmission device 100 to operate, for example, at least temporarily, as a transmitting and receiving device (“transceiver”).

[0035] The principle, according to the described embodiment, advantageously achieves less electromagnetic radiation, for example, during signal reception via optional receiving device 130, electromagnetic radiation that in some conventional transmission devices is caused, for example, by the characteristics of transmitting device 110 and, for example, affects the electromagnetic compatibility of conventional transmission devices.

[0036] The principle, according to the described embodiment, further advantageously achieves improved immunity in a further advantageous embodiment, because, for example, the same impedance between bus connectors causes the same current to flow into the bus connectors, and thus, for example, no balancing current flows through the bus load resistor, thereby avoiding, for example, distortion of differential signals or differential signals transmitted through the bus.

[0037] See Figure 2 In a further exemplary embodiment 100a, the impedance matching circuit 120 is provided with a first active semiconductor element 122a and a second active semiconductor element 122b, wherein the first active semiconductor element 122a is connectable to and / or to a first bus connector 101, and wherein the second active semiconductor element 122b is connectable to and / or to a second bus connector 102.

[0038] according to Figure 2 An exemplary configuration 100a may, for example, be formed together with an optional receiving device 130 to form a transceiver 100a or transceiver module 100a, which in a further exemplary embodiment also has an optional protection device 140 for preventing overvoltage or electrostatic discharge (ESD), the protection device being, for example, also connectable to, for example, bus lines 12a, 12b via bus connectors 101, 102.

[0039] In a further exemplary embodiment, the transceiver module 100a has a connection N_1 for a first reference potential of the bus system 10, which for example relates to a ground potential. In the case of an exemplary configuration of the bus system 10 as a CAN bus system, the connection N_1 can for example relate to a "CAN_GND" connection.

[0040] In a further exemplary embodiment, the transceiver module 100a has a connection N_2 for a second reference potential of the bus system 10, which for example relates to a potential associated with an operating voltage of the bus system 10 and / or of the transceiver module 100a. In the case of an exemplary configuration of the bus system 10 as a CAN bus system, the connection N_2 can for example relate to a "CAN_SUPPLY" connection.

[0041] Figure 3 According to a further exemplary embodiment, aspects of the transmitting device 110a and of the impedance matching circuit 120a are schematically shown. In a further exemplary embodiment, the transmitting device 110a has a connection N_3 to which a transmitting signal to be emitted via the bus system 10 can be fed. Figure 1 ) The transmitting device 110a in a further exemplary embodiment converts the transmitting signal into a differential signal and emits the differential signal via the bus connections 101, 102 to the transmission medium 12 of the differential bus system 10. Figure 1

[0042] In a further exemplary embodiment, it is provided that the impedance matching circuit 120a has at least one circuit component SK1 which is an analogue of at least one part TE1 of the transmitting device 110a.

[0043] In a further exemplary embodiment, the "analogue of at least one part of the transmitting device" refers to a circuit component SK1 which has the same component type in the same topology as the relevant, for example modelled, part TE1 of the transmitting device 110a (for example with the same component parameters or component values, for example apart from a predetermined tolerance).

[0044] In a further exemplary embodiment, it is provided that the impedance matching circuit 120a has at least one circuit component SK1, SK2, SK1', SK2' which for example are a complete analogue of the transmitting device 110a with respect to one another.

[0045] ​In further exemplary embodiments it is provided that the at least one circuit component SK1 has a series circuit consisting of the first diode D1'and the first transistor T1'and the second transistor T2', wherein the first transistor T1'corresponds, for example, to the at least one active semiconductor element 122a previously exemplarily explained. In further exemplary embodiments, the first transistor T1'and / or the second transistor T2' are / is respectively configured as a field effect transistor, for example, of the NMOS (n-channel MOSFET) or PMOS (p-channel MOSFET) type, or of a corresponding "high-voltage" variant of the n-channel MOSFET or p-channel MOSFET.

[0046] In further exemplary embodiments it is provided that the first diode D1'of the at least one circuit component SK1 corresponds to the first diode D1 of the at least one portion TE1 of the transmitting device 110a, for example, to a type of the first diode D1 of the at least one portion TE1 of the transmitting device 110a.

[0047] In further exemplary embodiments it is provided that the first transistor T1'of the at least one circuit component SK1 corresponds to the first transistor T1 of the at least one portion TE1 of the transmitting device 110a, for example, to a type of the first transistor T1 of the at least one portion TE1 of the transmitting device 110a.

[0048] In further exemplary embodiments it is provided that the second transistor T2' of the at least one circuit component SK1 corresponds to the second transistor T2 of the at least one portion TE1 of the transmitting device 110a, for example, to a type of the second transistor T2 of the at least one portion TE1 of the transmitting device 110a.

[0049] The at least one circuit component SK1 of the impedance matching circuit 120 thus exemplarily represents an analogue of the portion TE1 of the transmitting device 110a. In further exemplary embodiments, similar explanations apply with respect to the circuit component SK2 with respect to the portion TE2 of the transmitting device 110a.

[0050] In further exemplary embodiments, similar explanations apply with respect to a further circuit component SK1'with respect to the portion TE1'of the transmitting device 110a, for example, with the circuit components: connection N_2, power supply SQ1 connected to the connection N_2, transistor T3, RC network RC1. In other words, in further exemplary embodiments, the further circuit component SK1'has an analogue of the portion TE1'of the transmitting device 110a, and the further circuit component SK2', for example, has an analogue of the portion TE2' of the transmitting device 110a.

[0051] Thus in a further exemplary embodiment, the circuit components SK1, SK2, SK1', SK2' of the impedance matching circuit 120 are complete analogues of the transmitting means 110a of the parts TE1, TE2, TE1', TE2' with transmitting means. Figure 3

[0052] In a further exemplary embodiment, the first transistor T1 is an n-channel MOSFET, for example a "high voltage" n-channel MOSFET, as is the case for the exemplary counterpart transistor T1' of the impedance matching circuit 120a. In a further exemplary embodiment, the second transistor T2 is an n-channel MOSFET, as is the case for the exemplary counterpart transistor T2' of the impedance matching circuit 120a.

[0053] In a further exemplary embodiment, the diode D1 is provided as a polarity protection means. It is used in a further exemplary embodiment, for example, in addition, to decouple the base diode of the next components of the series circuit D1, T1, T2 (for example the transistor T1 with the base-drain junction) from the bus connection 102 and thus, for example, to achieve a "stealthiness " (for example with respect to the tolerance of the bus voltage of different polarity).

[0054] In a further exemplary embodiment, the transistor T4 is configured as a p-channel MOSFET, for example a "high voltage" p-channel MOSFET, for example in order to decouple the cathode of the diode D3 with its base diode from the bus connection 101.

[0055] In a further exemplary embodiment, the transistor T5 is configured as a p-channel MOSFET.

[0056] Figure 4 Some aspects of a transmitting means 110b and an impedance matching circuit 120b according to a further exemplary embodiment are schematically shown. While the transmitting means 110b has a similar structure or topology as the transmitting means 110a according to Figure 3 the impedance matching circuit 120b according to Figure 3 is reduced compared to the impedance matching circuit 120a according to Figure 2 for example in such a way that the circuit components SK1', SK2' according to Figure 3 are not present in the impedance matching circuit 120b according to Figure 4 The impedance matching circuit 120b according to Figure 4 thus has the circuit components SK1, SK2 which are analogues of the parts TE1, TE2 of the transmitting means 110b, but not of the further parts TE1', TE2' of the transmitting means 110b. ​

[0057] In a further exemplary embodiment, using press Figure 4 The impedance matching circuit 120b can also cause impedance Z1, Z2 ( Figure 1 At least a portion of the adjustment reduces unwanted radiation, for example, during the receiving operation of a transmission device having a transmitting device 110b and an impedance matching circuit 120b. Due to the small number of components, according to Figure 4 Implementation method 120b is compared with Figure 3 Implementation 120a has a smaller unit area consumption, for example, for the substrate (e.g., made of silicon) that can be used for implementation.

[0058] In a further exemplary embodiment, impedance matching circuits 120, 120a, 120b thus form analog or replicas of transmitting devices 110, 110a, 110b, wherein, for example, circuit components SK1, SK2 ( Figure 3 The portions TE1 and TE2 of the transmitting device 110a, which are simulated by them, are reverse-connected with respect to bus connectors 101 and 102. Therefore, the series circuit consisting of components D1′, T1′, and T2′ (corresponding to circuit component SK1) is connected, for example, to the first bus connector 101, and the circuit portion TE1 of the transmitting device 110a, simulated by the series circuit SK1, is connected to the second bus connector 102, referring, for example, to the anode of diode D1 (not shown in more detail). This is applied in a corresponding manner to circuit component SK2 (at bus connector 101) and portion TE2 (at bus connector 101) in a further exemplary embodiment.

[0059] Through the aforementioned wiring of components SK1, SK2, TE1, TE2 with respect to bus connectors 101, 102, in a further exemplary embodiment, for example, the transceiver 100a being received ( Figure 2 Regarding bus connectors 101 and 102 (e.g., CANH and CANL in CAN bus system 10), they have the same impedances Z1 and Z2 even at their (passive during receiving operation) "transmitter" 110a. Figure 1 Therefore, its influence on radiation results is reduced or eliminated.

[0060] In a further exemplary embodiment, the impedance matching circuits 120, 120a, 120b, representing, for example, analog or replicas of the transmitting devices 110, 110a, 110b, are not, for example, never placed in an active operating mode (similar to transmission via bus connectors 101, 102), as is possible, at least temporarily, for example, for desired transmission operation in the transmitting devices 110, 110a, 110b in a further exemplary embodiment. This is in Figure 3is symbolically represented by the example that no control signal acts on the switches S1 ', S2', which are thus, for example, always open, in contrast to the corresponding switches S1, S2, on which the transmission signal of the transmission device 110a with the connection N_3 acts.

[0061] In a further exemplary embodiment it is provided that the bus system 10 Figure 1 has one of the following types: CAN (Controller Area Network), CAN-FD (CAN Flexible Data Rate), CAN-FD-SIC (CAN-FD Signal Improvement Capability), CAN-XL (CAN Extra Large), LVDS (Low Voltage Differential Signaling), 10BASE-T1S. In a further exemplary embodiment, the bus system 10 can also have a type other than the previously exemplarily mentioned types, which has a differential signal transmission.

[0062] A further exemplary embodiment, namely Figure 5 , relates to a method for operating a transmission device 100 Figure 1 for a differential bus system 10, with a first bus connection 101 and a second bus connection 102 for connecting to a transmission medium 12, for example to a differential bus line 12a, 12b, of the differential bus system 10, and with a transmission device 110 connectable to the first bus connection 101 and / or to the second bus connection 102, wherein the transmission device 100 has an impedance matching circuit 120, wherein the method has: adjusting 200 Figure 5 the impedance Z1, Z2 at the first bus connection 101 and / or at the second bus connection 102.

[0063] Figure 5 An optional further block 202 symbolizes an optional further operation of the transmission device 100, the subject matter of which is, for example, with regard to the transmission and / or reception of signals by the differential bus system 10.

[0064] A further exemplary embodiment, namely Figure 6application 300 of at least one of the following elements a) adjusting 302 the impedance (e.g. the first impedance Z1 and / or the second impedance Z2) at the at least first and / or second bus connection 101, 102, b) adapting 304 the first impedance Z1 at the first bus connection 101 to the second impedance Z2 at the second bus connection 102, e.g. up to a predetermined difference, and / or vice versa, c) reducing 306 electromagnetic radiation, e.g. when receiving a signal by means of the transmission device, d) reducing 308 errors or increasing efficiency, e.g. during an arbitration phase in a bus system 10 configured as CAN-XL, in accordance with the transmission device and / or the method according to the described embodiments.

Claims

1. A transmission device (100; 100a) for a differential bus system (10), the transmission device having a first bus connector (101) and a second bus connector (102) for connection to a transmission medium (12) of the differential bus system (10), and having a transmitter (110; 110a; 110b) for connection to and / or to the first bus connector (101) and the second bus connector (102), further having an impedance matching circuit (120; 120a; 120b), the impedance matching circuit being configured to affect the impedance (Z1, Z2) at the first bus connector (101) and / or the second bus connector (102), in, The impedance matching circuit (120) has at least one circuit component (SK1; SK2), which is a simulation of at least one part (TE1; TE2) of the transmitting device (110). In this circuit, at least one circuit component (SK1; SK2) of the impedance matching circuit (120) is connected to the opposite bus connector to at least one part (TE1; TE2) of the transmitter (110) that it simulates.

2. The transmission device (100) according to claim 1, wherein, The impedance matching circuit (120) is configured to affect the impedance at the first bus connector (101) and / or the second bus connector (102) such that the impedance (Z1) at the first bus connector (101) and the impedance (Z2) at the second bus connector (102) deviate from each other by a predetermined difference.

3. The transmission device (100) according to claim 1, wherein, The impedance matching circuit (120) has at least one active semiconductor element (122).

4. The transmission device (100) according to claim 1, wherein, The impedance matching circuit (120) has a first active semiconductor element (122a) and a second active semiconductor element (122b), wherein the first active semiconductor element (122a) can be connected to and / or to the first bus connector (101), and wherein the second active semiconductor element (122b) can be connected to and / or to the second bus connector (102).

5. The transmission device (100) according to claim 1, wherein, The impedance matching circuit (120) has at least one circuit component (SK1; SK2), which is a complete simulation of the transmitting device (110).

6. The transmission device (100) according to claim 1, wherein, The at least one circuit component (SK1) has a series circuit consisting of a first diode (D1'), a first transistor (T1'), and a second transistor (T2').

7. The transmission device (100) according to claim 6, wherein, a) The first diode (D1') of the at least one circuit component (SK1) corresponds to the first diode (D1) of at least one portion (TE1) of the transmitting device (110), and / or, wherein, b) The first transistor (T1') of the at least one circuit component (SK1) corresponds to the first transistor (T1) of at least one portion (TE1) of the transmitting device (110), and / or, wherein, c) The second transistor (T2') of the at least one circuit component (SK1) corresponds to the second transistor (T2) of at least one portion (TE1) of the transmitting device (110).

8. The transmission device (100) according to claim 7, wherein, The first diode (D1') of the at least one circuit component (SK1) corresponds to a type of the first diode (D1) of at least one part (TE1) of the transmitting device (110).

9. The transmission device (100) according to claim 7, wherein, The first transistor (T1') of the at least one circuit component (SK1) corresponds to a type of the first transistor (T1) of at least one part (TE1) of the transmitting device (110).

10. The transmission device (100) according to claim 7, wherein, The second transistor (T2´) of at least one circuit component (SK1) corresponds to a type of the second transistor (T2) of at least one part (TE1) of the transmitting device (110).

11. The transmission device (100) according to claim 1, wherein, A receiving device (130) is provided.

12. The transmission device (100) according to claim 1, wherein, The bus system (10) has one of the following types: CAN, CAN-FD, CAN-FD-SIC, CAN-XL, LVDS, 10BASE-T1S.

13. The transmission device (100) according to claim 1, wherein, The transmission medium (12) is a differential bus line (12a, 12b).

14. A method for operating a transmission device (100) for a differential bus system (10), the transmission device having a first bus connector (101) and a second bus connector (102) for connection to a transmission medium (12) of the differential bus system (10), and having a transmitter (110) capable of being connected to and / or to the first bus connector (101) and the second bus connector (102), wherein, The transmission device (100) has an impedance matching circuit (120), wherein the method includes: adjusting (200) the impedance at the first bus connector (101) and / or the second bus connector (102), The impedance matching circuit (120) includes at least one circuit component (SK1; SK2), which is a simulation of at least one part (TE1; TE2) of the transmitting device (110). In this circuit, at least one circuit component (SK1; SK2) of the impedance matching circuit (120) is connected to the opposite bus connector to at least one part (TE1; TE2) of the transmitter (110) that it simulates.

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