Level conversion circuit, CAN XL transceiver, bus adapter

Abstract

The utility model belongs to the field of automobile electronic communication technology, specifically relates to a kind of level conversion circuit, CAN XL transceiver, bus adapter, and wherein level conversion circuit includes: level conversion unit, for the TX signal after isolation is converted into CANH / CANL differential signal, and make differential level change between ±1V;And, receiving conversion unit, its input end is electrically connected with the output end of level conversion unit, for CANH / CANL differential signal is converted into single-ended digital signal.

Description

[0001] This application is based on and claims priority to Chinese Patent Application No. 202510768588.3, ​​filed on June 10, 2025, and Chinese Patent Application No. 202510926096.2, filed on July 4, 2025. The entire contents of the above applications are incorporated herein by reference. Technical Field

[0002] This utility model relates to the field of automotive electronic communication, and in particular to a level conversion circuit, a CAN XL transceiver, and a bus adapter. Background Technology

[0003] CAN XL (Controller Area Network with Extra Long payload) is an evolution of the next-generation CAN protocol, released in 2022 by the CAN in Automation (CiA) organization (CiA 610-1 standard), aiming to solve the bandwidth bottleneck of traditional CAN / CAN FD. Current automotive networks are upgrading from CAN FD to the CAN XL protocol, but there are voltage compatibility issues at the physical layer between the two. CAN FD: Adopts ISO 11898-2 standard, differential level amplitude ±2V (dominant: CANH=3.5V, CANL=1.5V); CAN XL: Must meet ±1V differential level (dominant: CANH=3V, CANL=2V).

[0004] Traditional transceivers are not directly compatible, and existing conversion solutions suffer from problems such as high circuit complexity and high cost. Utility Model Content

[0005] The purpose of this invention is to provide a level conversion circuit, a CAN XL transceiver, and a bus adapter.

[0006] To solve the above-mentioned technical problems, this utility model provides a level conversion circuit, including: A level conversion unit is used to convert the isolated TX signal into a CANH / CANL differential signal and to vary the differential level between ±1V; and, The receiving conversion unit has its input terminal electrically connected to the output terminal of the level conversion unit, and is used to convert the CANH / CANL differential signal into a single-ended digital signal.

[0007] Furthermore, the level conversion unit employs a FlexRay transceiver; The FlexRay transceiver is adapted to convert a received TX signal into a CANH / CANL differential signal and to vary the differential level between ±1V.

[0008] Furthermore, the FlexRay transceiver uses the TJA1080A chip.

[0009] Furthermore, the level conversion circuit also includes: The signal isolation unit includes: a digital isolator; The TX signal sent by the CAN FD controller is connected to the level conversion unit via a digital isolator.

[0010] The signal isolation unit includes a digital isolator; the TX signal sent by the CAN FD controller is connected to the level conversion unit through the digital isolator.

[0011] Furthermore, the receiving conversion unit includes: a comparator; The CANH signal is connected to the non-inverting input of the comparator, and the CANL signal is connected to the inverting input of the comparator, so that the CANH / CANL differential signal is converted into a single-ended digital signal by the comparator.

[0012] On the other hand, this utility model also provides a CAN XL transceiver, including: the level conversion circuit as described above.

[0013] Thirdly, this utility model also provides a bus adapter, including: the CAN XL transceiver as described above.

[0014] The beneficial effects of this utility model are that the level conversion circuit of this utility model provides a reliable level conversion scheme through the level conversion unit and the receiving conversion unit, which meets the ±1V differential level required by the CAN XL physical layer. It solves the problems that traditional transceivers cannot be directly compatible, or that existing conversion schemes have large signal delays, high circuit complexity, and high costs. It provides an effective solution for existing or standard CAN FD controllers to support the emerging CAN XL bus physical layer.

[0015] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention are realized and obtained through the structures particularly pointed out in the description and the accompanying drawings.

[0016] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A schematic block diagram of the level conversion circuit involved in some embodiments is shown; Figure 2 A schematic block diagram of a level conversion circuit including a signal isolation unit is shown in some embodiments; Figure 3 Partial circuitry of the level conversion circuitry involved in some embodiments is shown; Figure 4 Partial circuitry of a comparator as illustrated in some embodiments is shown; Figure 5 It shows Figure 3 Simulation diagram of the level conversion circuit. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] The following is an explanation of some of the technical terms used in this embodiment: TTL (Transistor-Transistor Logic) signals: Transistor-to-transistor logic level signals; CAN FD (Controller Area Network with Flexible Data-Rate): A controller area network with flexible data rates. CAN XL (Controller Area Network with Extra Long payload): A controller area network that supports extra-long payloads.

[0021] Current vehicle networks are upgrading from CAN FD to CAN XL protocol, but there are voltage compatibility issues at the physical layer between the two: CAN FD: Adopts ISO 11898-2 standard, differential level amplitude ±2V (dominant: CANH=3.5V, CANL=1.5V); CAN XL: Must meet ±1V differential level (dominant: CANH=3V, CANL=2V).

[0022] Traditional transceivers are not directly compatible, and existing conversion solutions suffer from problems such as high circuit complexity and high cost.

[0023] Therefore, at least one embodiment provides a level conversion circuit, including: a level conversion unit for converting an isolated TX signal into a CANH / CANL differential signal and varying the differential level between ±1V; and a receiving conversion unit, the input of which is electrically connected to the output of the level conversion unit, for converting the CANH / CANL differential signal into a single-ended digital signal.

[0024] The level conversion circuit in this embodiment provides a reliable level conversion scheme through a level conversion unit and a receive conversion unit, which meets the ±1V differential level required by the CAN XL physical layer. It solves the problems of traditional transceivers not being directly compatible, or existing conversion schemes having large signal delays, high circuit complexity, and high costs. It provides an effective solution for existing or standard CANFD controllers to support the emerging CAN XL bus physical layer.

[0025] The various non-limiting embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

[0026] like Figure 1 As shown, this embodiment provides a level conversion circuit, including: a level conversion unit for converting the isolated TX signal into a CANH / CANL differential signal and making the differential level vary between ±1V; and a receiving conversion unit, the input terminal of which is electrically connected to the output terminal of the level conversion unit, for converting the CANH / CANL differential signal into a single-ended digital signal.

[0027] In some embodiments, the level conversion unit employs a FlexRay transceiver; the FlexRay transceiver is adapted to convert a received TX signal into a CANH / CANL differential signal and to vary the differential level between ±1V.

[0028] In some embodiments, such as Figure 2 As shown, the level conversion circuit further includes a signal isolation unit, which includes a digital isolator; the TX signal sent by the CAN FD controller is connected to the level conversion unit through the digital isolator.

[0029] Specifically, such as Figure 3As shown, the digital isolator U22 is, for example but not limited to, an NSI8221N1 type digital isolator. It receives the TX signal CAN_XL_TXD1 output from the CAN FD controller, and after electrically isolating the TX signal CAN_XL_TXD1, outputs it to the RXD terminal of the TJA1080A chip. The differential driver inside the TJA1080A chip U21 converts the single-ended signal output by the digital isolator into ±1V differential signals CCAN1_H and CCAN1_L that conform to the CAN XL physical layer standard.

[0030] Specifically, such as Figure 3 As shown, the FlexRay transceiver includes a TJA1080A chip U21. The TJA1080A chip is compatible with the CAN XL physical layer through circuit reconfiguration.

[0031] In some embodiments, such as Figure 4 As shown, the receiving conversion unit includes: a comparator U1; the CANH signal is connected to the non-inverting input of the comparator U1, and the CANL signal is connected to the inverting input of the comparator U1, so as to convert the CANH / CANL differential signal into a single-ended digital signal through the comparator U1.

[0032] Specifically, the differential signals of CANH / CANL are converted into single-ended RX1 digital signals by comparator U1.

[0033] This embodiment cleverly reuses the existing FlexRay transceiver TJA1080A chip for CAN XL physical layer compatibility, making full use of the functionality and stability of existing devices to replace immature, unverified, or expensive dedicated CAN XL transceiver chips.

[0034] This embodiment is also applicable to high-frequency signal conversion (supporting CAN XL 10Mbps), such as... Figure 5 As shown, it is for Figure 3 The simulation results of the circuit show that the waveform on the right is denser than that on the left, indicating that the circuit can work in a high-frequency environment (such as 20MHz). According to the numerical scale on the right side of the figure, the differential voltage of the waveform on the left before level conversion is 2-3V, while the differential voltage of the waveform on the right after level conversion is ±1V.

[0035] It should be noted that the CAN FD controller mentioned in this embodiment supports at least the CAN XL protocol. After the CAN FD controller generates a data frame that conforms to the CAN XL protocol layer, it outputs a TX signal through the corresponding pin. The level conversion circuit in this embodiment is responsible for converting the TX signal into a ±1V differential signal that conforms to the CAN XL physical layer standard.

[0036] In summary, the level conversion circuit of this embodiment provides a reliable CAN FD to CAN XL level conversion scheme, which meets the ±1V differential level required by the CAN XL physical layer. It solves the problems of traditional transceivers not being directly compatible, or existing conversion schemes having large signal delays, high circuit complexity, and high costs. It provides an effective solution for existing or standard CAN FD controllers to support the emerging CAN XL bus physical layer.

[0037] Some embodiments also provide a CAN XL transceiver, including: the level conversion circuit as described above.

[0038] Specifically, the level conversion circuit can refer to the level conversion circuits in the aforementioned schemes, and will not be described in detail here.

[0039] Some embodiments also provide a bus adapter, including: the CAN XL transceiver as described above.

[0040] Some embodiments also provide a level conversion method, including: converting a TX signal sent by a CAN FD controller into a CANH / CANL differential signal via a level conversion unit, and varying the differential level between ±1V; and converting the CANH / CANL differential signal into a single-ended digital signal by electrically connecting the input terminal of the receiving conversion unit to the output terminal of the level conversion unit.

[0041] In some embodiments, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and embedded program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action.

[0042] In addition, the functional modules in the various embodiments of this utility model can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0043] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a readable storage medium. Based on this understanding, the technical solution of this utility model, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This embedded software product is stored in a storage medium and executes all or part of the steps of the methods described in the various embodiments of this utility model.

[0044] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A level conversion circuit, characterized in that, include: The level conversion unit is used to convert the isolated TX signal into a CANH / CANL differential signal and to make the differential level vary between ±1V; as well as, The receiving conversion unit has its input terminal electrically connected to the output terminal of the level conversion unit, and is used to convert the CANH / CANL differential signal into a single-ended digital signal.

2. The level conversion circuit according to claim 1, characterized in that, The level conversion unit uses a FlexRay transceiver; The FlexRay transceiver is adapted to convert a received TX signal into a CANH / CANL differential signal and to vary the differential level between ±1V.

3. The level conversion circuit according to claim 2, characterized in that, The FlexRay transceiver uses the TJA1080A chip.

4. The level conversion circuit according to claim 1, characterized in that, Also includes: The signal isolation unit includes: a digital isolator; The TX signal sent by the CAN FD controller is connected to the level conversion unit via a digital isolator.

5. The level conversion circuit according to claim 1, characterized in that, The receiving and conversion unit includes: a comparator; The CANH signal is connected to the non-inverting input of the comparator, and the CANL signal is connected to the inverting input of the comparator, so that the CANH / CANL differential signal is converted into a single-ended digital signal by the comparator.

6. A CAN XL transceiver, characterized in that, include: The level conversion circuit as described in any one of claims 1-5.

7. A bus adapter, characterized in that, include: The CAN XL transceiver as described in claim 6.

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