Controller area network (CAN) interface circuit, integrated circuit chip and electrical equipment

Abstract

The embodiment of the invention provides a controller area network (CAN) interface circuit, an integrated circuit chip and electrical equipment, the CAN interface circuit comprises a first CAN transceiver, a second CAN transceiver and a detection module, a first CANH port and a first CANL port of the first CAN transceiver are respectively connected with a first data line and a second data line in a CAN bus; a second CANH port and a second CANL port of the second CAN transceiver are respectively connected with the second data line and the first data line; the detection module indicates at least one of whether the connection between the first CAN transceiver and the CAN bus is correct or not and whether the connection between the second CAN transceiver and the CAN bus is correct or not based on a first signal sent by a first received data (RXD) port of the first CAN transceiver and / or a second signal sent by a second RXD port of the CAN transceiver; the first signal is sent by the first CAN transceiver in response to a wake-up signal on the CAN bus in a low power consumption mode; the second signal is sent by the second CAN transceiver in response to the wake-up signal in the low power consumption mode.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to a controller area network (CAN) interface circuit, an integrated circuit chip and an electrical device. Background Art

[0002] With the development of vehicle technology, the requirements for automobile safety performance are getting higher and higher. Airbags are installed on every car to ensure the safety of passengers. During the driving process of the car, if a collision occurs, the airbag sensor will first receive the impact signal, and then transmit this acceleration signal to the microcontroller. The microcontroller compares the signal to determine whether the airbag deployment conditions are met. If the conditions are met, the airbag will be opened. In some chips, due to the advantages of flexible data rate and high stability, the CAN bus is used for data transmission between the sensor and the microcontroller; or the vehicle parameters are read through the CAN bus and the door is unlocked through the CAN bus when the vehicle collides. This usually uses a CAN transceiver to process and transmit the signal between the CAN bus and the processor. Therefore, the stable operation of the CAN transceiver plays a particularly important role in the reliability of the car airbag. The CAN bus usually has two data lines: CANH and CANL. During the design and manufacturing process, the CAN module may have data line connection errors due to human factors, that is, the interface that needs to be connected to CANH is connected to CANL, and the interface that needs to be connected to CANL is connected to CANH, which makes the communication between the CAN modules on the CAN bus abnormal, and also makes the CAN module unable to work normally. Such abnormal phenomena are usually difficult to detect, and sometimes even require a lot of effort to troubleshoot. Therefore, how to promptly determine the cause of the abnormal CAN bus connection, eliminate the fault in time, and make the CAN module work normally is an urgent problem to be solved. Summary of the invention

[0003] The embodiments of the present disclosure provide a CAN interface circuit, an integrated circuit chip, and an electrical device.

[0004] According to a first aspect of an embodiment of the present disclosure, a CAN interface circuit is provided, the CAN interface circuit comprising: a first CAN transceiver, a second CAN transceiver and a detection module, wherein: The first CANH port and the first CANL port of the first CAN transceiver are used to connect to the first data line and the second data line in the CAN bus respectively; The second CANH port and the second CANL port of the second CAN transceiver are used to connect to the second data line and the first data line respectively; The detection module is used to indicate at least one of the following based on a first signal sent by a first receive data (Receive eXternalData, RXD) port of the first CAN transceiver and / or a second signal sent by a second RXD port of the CAN transceiver: whether the connection between the first CAN transceiver and the CAN bus is correct, and whether the connection between the second CAN transceiver and the CAN bus is correct; wherein, the first signal is sent by the first CAN transceiver in low power mode in response to a wake-up signal on the CAN bus; and the second signal is sent by the second CAN transceiver in low power mode in response to the wake-up signal.

[0005] In some embodiments, the detection module includes: a first transmission gate, wherein: The negative logic control terminal of the first transmission gate is connected to the first RXD port; The positive logic control terminal of the first transmission gate is connected to the second RXD port; The input end of the first transmission gate is used to input a predetermined signal; The output end of the first transmission gate is used to output a judgment signal, wherein when the level of the judgment signal is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is correct and / or the connection between the second CAN transceiver and the CAN bus is incorrect; when the level of the judgment signal is different from the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is incorrect and / or the connection between the second CAN transceiver and the CAN bus is correct.

[0006] In some embodiments, the detection module further includes: an inverter and a second transmission gate, wherein: The inverter is used to input the enable signal of the detection module and output an inverted enable signal; The input terminal of the second transmission gate is used to input a predetermined signal; The enable signal and the inverted enable signal are used to control the on and off of the second transmission gate; When the enable signal is enabled, the second transmission gate is controlled to be turned on so that the second transmission gate outputs the predetermined signal to the input end of the first transmission gate.

[0007] In some embodiments, the CAN interface circuit further includes: a CAN controller and a selection module; The selection module is used for at least one of the following: When the connection between the first CAN transceiver and the CAN bus is correct, switching on the connection between the CAN controller and the first CAN transceiver, and switching off the connection between the CAN controller and the second CAN transceiver; When the connection between the second CAN transceiver and the CAN bus is correct, the connection between the CAN controller and the second CAN transceiver is turned on, and the connection between the CAN controller and the first CAN transceiver is turned off.

[0008] According to a second aspect of an embodiment of the present disclosure, a CAN interface circuit is provided, the CAN interface circuit comprising: a first CAN transceiver, a second CAN transceiver, a detection module and a control module, wherein: The first CANH port and the first CANL port of the first CAN transceiver are used to connect to the first data line and the second data line in the CAN bus respectively; The second CANH port and the second CANL port of the second CAN transceiver are used to connect to the second data line and the first data line respectively; A control module, configured to control the first CAN transceiver and the second CAN transceiver to enter a low power consumption mode respectively, and generate a wake-up signal on the CAN bus when the first CAN transceiver and the second CAN transceiver are in the low power consumption mode respectively; The detection module is used to indicate at least one of the following based on a first signal sent by the first RXD port of the first CAN transceiver and / or a second signal sent by the second RXD port of the CAN transceiver: whether the connection between the first CAN transceiver and the CAN bus is correct, and whether the connection between the second CAN transceiver and the CAN bus is correct; wherein, the first signal is sent by the first CAN transceiver in low power mode in response to a wake-up signal on the CAN bus; and the second signal is sent by the second CAN transceiver in low power mode in response to the wake-up signal.

[0009] In some embodiments, the detection module includes: a first transmission gate, wherein: The negative logic control terminal of the first transmission gate is connected to the first RXD port; The positive logic control terminal of the first transmission gate is connected to the second RXD port; The input end of the first transmission gate is used to input a predetermined signal; The output end of the first transmission gate is used to output a judgment signal, wherein when the level of the judgment signal is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is correct and / or the connection between the second CAN transceiver and the CAN bus is incorrect; when the level of the judgment signal is different from the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is incorrect and / or the connection between the second CAN transceiver and the CAN bus is correct.

[0010] In some embodiments, the detection module further includes: an inverter and a second transmission gate, wherein: The control module is further configured to output an enable signal of the detection module to the inverter; The inverter is used to output an inverted enable signal based on the enable signal; The input terminal of the second transmission gate is used to input a predetermined signal; The enable signal and the inverted enable signal are used to control the on and off of the second transmission gate; When the enable signal is enabled, the second transmission gate is controlled to be turned on so that the second transmission gate outputs the predetermined signal to the input end of the first transmission gate.

[0011] In some embodiments, the CAN interface circuit further includes: a CAN controller and a selection module; The controller is used for at least one of the following: When the connection between the first CAN transceiver and the CAN bus is correct, controlling the selection module to enable the connection between the CAN controller and the first CAN transceiver, and to disable the connection between the CAN controller and the second CAN transceiver; When the connection between the second CAN transceiver and the CAN bus is correct, the selection module is controlled to enable the connection between the CAN controller and the second CAN transceiver, and to disable the connection between the CAN controller and the first CAN transceiver.

[0012] According to a third aspect of an embodiment of the present disclosure, an integrated circuit chip is provided, wherein the integrated circuit chip includes the CAN interface circuit described in the first aspect and the second aspect.

[0013] According to a fourth aspect of an embodiment of the present disclosure, an electrical device is provided, the electrical device comprising: The CAN interface circuit described in the first aspect; or the CAN interface circuit described in the second aspect; or the integrated circuit chip described in the third aspect.

[0014] The embodiments of the present disclosure provide a CAN interface circuit, an integrated circuit chip and an electrical device, wherein the CAN interface circuit comprises: a first CAN transceiver, a second CAN transceiver and a detection module, wherein the first CANH port and the first CANL port of the first CAN transceiver are used to respectively connect to the first data line and the second data line in a CAN bus; the second CANH port and the second CANL port of the second CAN transceiver are used to respectively connect to the second data line and the first data line; the detection module is used to indicate at least one of the following based on a first signal sent by the first RXD port of the first CAN transceiver and / or a second signal sent by the second RXD port of the CAN transceiver: whether the connection between the first CAN transceiver and the CAN bus is correct, whether the connection between the second CAN transceiver and the CAN bus is correct; wherein the first signal is sent by the first CAN transceiver in low power consumption mode in response to a wake-up signal on the CAN bus; and the second signal is sent by the second CAN transceiver in low power consumption mode in response to the wake-up signal. In this way, based on the fact that the RXD port of the CAN transceiver will generate a specific signal after being awakened, by connecting the first CAN transceiver and the second CAN transceiver to the CAN bus in opposite ways, the first signal and the second signal of the first CAN transceiver and the second CAN transceiver are triggered based on the wake-up signal on the CAN bus. Without manual troubleshooting, it is possible to determine whether the connection between the first CAN transceiver and the second CAN transceiver and the CAN bus is correct, thereby being able to detect faults in a timely manner and reducing data transmission errors caused by errors in the CAN transceiver and the CAN bus. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of a CAN interface circuit structure according to an exemplary embodiment; Figure 2 is a schematic diagram of a CAN transceiver circuit structure according to an exemplary embodiment; Figure 3 is a timing diagram of waking up a CAN transceiver according to an exemplary embodiment; Figure 4 is a schematic diagram of a wake-up signal timing sequence according to an exemplary embodiment; Figure 5 is another schematic diagram of a CAN interface circuit structure according to an exemplary embodiment; Figure 6 is a schematic diagram of another CAN interface circuit structure according to an exemplary embodiment; Figure 7 The diagram is a schematic diagram of another CAN interface circuit structure according to an exemplary embodiment. DETAILED DESCRIPTION

[0016] In order to make the technical solutions and beneficial effects of the present invention more clearly understandable, the following is a detailed description by listing specific embodiments. The drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0017] The embodiments of the present disclosure are not exhaustive, but are only illustrative of some embodiments, and are not intended to be a specific limitation on the scope of protection of the present disclosure. In the absence of contradiction, each step in a certain embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a certain embodiment can also be implemented as an independent embodiment, and the order of the steps in a certain embodiment can be arbitrarily exchanged. In addition, the optional implementation methods in a certain embodiment can be arbitrarily combined; in addition, the embodiments can be arbitrarily combined, for example, some or all of the steps of different embodiments can be arbitrarily combined, and a certain embodiment can be arbitrarily combined with the optional implementation methods of other embodiments.

[0018] In each embodiment of the present disclosure, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between the embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form a new embodiment based on their internal logical relationships.

[0019] The terms used in the embodiments of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0020] In the embodiments of the present disclosure, unless otherwise specified, elements expressed in the singular form, such as "a", "an", "the", "above", "said", "aforementioned", "this", etc., may mean "one and only one", or "one or more", "at least one", etc. For example, when using articles such as "a", "an", "the" in English in translation, the noun after the article may be understood as a singular expression or a plural expression.

[0021] In the embodiments of the present disclosure, “plurality” refers to two or more.

[0022] In some embodiments, the terms “at least one”, “one or more”, “a plurality of”, “multiple”, etc. can be used interchangeably.

[0023] In some embodiments, "at least one of A and B", "A and / or B", "A in one case, B in another case", "A in one case, B in another case", etc., may include the following technical solutions according to the situation: in some embodiments, A (A is executed independently of B); in some embodiments, B (B is executed independently of A); in some embodiments, execution is selected from A and B (A and B are selectively executed); in some embodiments, A and B (A and B are both executed). When there are more branches such as A, B, C, etc., the above is also similar.

[0024] In some embodiments, the recording method of "A or B" may include the following technical solutions according to the situation: in some embodiments, A (A is executed independently of B); in some embodiments, B (B is executed independently of A); in some embodiments, execution is selected from A and B (A and B are selectively executed). When there are more branches such as A, B, C, etc., the above is also similar.

[0025] The prefixes such as "first" and "second" in the embodiments of the present disclosure are only used to distinguish different description objects, and do not constitute restrictions on the position, order, priority, value or content of the description objects. The statement of the description object refers to the description in the context of the claims or embodiments, and should not constitute redundant restrictions due to the use of prefixes. For example, if the description object is a "field", the ordinal number before the "field" in the "first field" and the "second field" does not limit the position or order between the "fields", and the "first" and "second" do not limit whether the "fields" they modify are in the same message, nor do they limit the order of the "first field" and the "second field". For another example, if the description object is a "level", the ordinal number before the "level" in the "first level" and the "second level" does not limit the priority between the "levels". For another example, the numerical value of the description object is not limited by the ordinal number, and can be one or more. Taking the "first device" as an example, the numerical value of the "device" can be one or more. In addition, the objects modified by different prefixes may be the same or different. For example, if the description object is "device", then the "first device" and the "second device" may be the same device or different devices, and their types may be the same or different. For another example, if the description object is "information", then the "first information" and the "second information" may be the same information or different information, and their contents may be the same or different.

[0026] In some embodiments, “including A”, “comprising A”, “used to indicate A”, and “carrying A” can be interpreted as directly carrying A or indirectly indicating A.

[0027] In some embodiments, terms such as “…”, “determine…”, “in the case of…”, “at the time of…”, “when…”, “if…”, “if…”, etc. can be used interchangeably.

[0028] In some embodiments, terms such as "greater than", "greater than or equal to", "not less than", "more than", "more than or equal to", "not less than", "higher than", "higher than or equal to", "not lower than", and "above" can be replaced with each other, and terms such as "less than", "less than or equal to", "not greater than", "less than", "less than or equal to", "no more than", "lower than", "lower than or equal to", "not higher than", and "below" can be replaced with each other.

[0029] In addition, each element, each row, or each column in the table of the embodiments of the present disclosure may be implemented as an independent embodiment, and the combination of any elements, any rows, and any columns may also be implemented as an independent embodiment.

[0030] The present disclosure provides a CAN interface circuit, such as Figure 1 As shown, the CAN interface circuit includes: a first CAN transceiver 110, a second CAN transceiver 120 and a detection module 130, wherein: The first CANH port and the first CANL port of the first CAN transceiver 110 are used to connect to the first data line and the second data line in the CAN bus respectively; The second CANH port and the second CANL port of the second CAN transceiver 120 are used to connect to the second data line and the first data line respectively; The detection module 130 is used to indicate at least one of the following based on a first signal sent by a first RXD port of the first CAN transceiver 110 and / or a second signal sent by a second RXD port of the CAN transceiver: whether the connection between the first CAN transceiver 110 and the CAN bus is correct, and whether the connection between the second CAN transceiver 120 and the CAN bus is correct; The first signal is sent by the first CAN transceiver 110 in low power mode in response to a wake-up signal on the CAN bus; and the second signal is sent by the second CAN transceiver 120 in low power mode in response to the wake-up signal.

[0031] Here, the CANH port represents the high level signal port of the CAN bus, and the CANL port represents the low level signal port of the CAN bus. It can be understood that the CANH data line represents the high level signal data line of the CAN bus, and the CANL data line represents the low level signal data line of the CAN bus.

[0032] In a possible implementation, the first CAN transceiver 110 , the second CAN transceiver 120 , and the detection module 130 may belong to the same integrated circuit chip.

[0033] In a possible implementation, at least one of the first CAN transceiver 110 , the second CAN transceiver 120 and the detection module 130 is independent of the other items and does not belong to the same integrated circuit chip.

[0034] The functional components of CAN bus transmission include CAN controller 140 and CAN transceiver. CAN controller 140 is a hardware module used to control the sending and receiving of data frames on the CAN bus and is responsible for managing frame error handling. CAN controller 140 can exist independently or be integrated into a processor, microcontroller or embedded system. The independent CAN controller 140 communicates with the processor through the bus or peripheral interface, and can independently send and receive CAN bus data without the intervention of the processor.

[0035] The CAN transceiver is used to convert and adjust the signals between the CAN controller 140 and the physical layer of the CAN bus. The main function of the CAN transceiver is to convert the digital signal output by the CAN controller 140 into the physical signal required by the CAN bus, and to convert the physical signal received on the CAN bus into a digital signal and pass it to the CAN controller 140 for processing.

[0036] The CAN bus uses differential mode to transmit data. CAN can have two data lines: CANH data line and CANL data line for transmitting a pair of differential signals.

[0037] The CAN transceiver is used to connect to the CANH data line and CANL data line of the CAN bus through the CANH port and the CANL port respectively, and is connected to the CAN controller 140 through the receive data (RXD) port and the transmit data (TXD) port to achieve signal conversion and adjustment between the CAN controller 140 and the physical layer of the CAN bus.

[0038] The first data line and the second data line may be two data lines of a CAN bus. The first data line and the second data line may be a CANH data line and a CANL data line respectively; the first data line and the second data line may also be a CANL data line and a CANH data line respectively.

[0039] Here, the first CAN transceiver 110 and the second CAN transceiver 120 are used to connect to the CAN bus in different connection modes, that is, one of the first CAN transceiver 110 and the second CAN transceiver 120 must be correctly connected to the CAN bus, while the other CAN transceiver is incorrectly connected to the CAN bus.

[0040] For example, if the first data line and the second data line are the CANH data line and the CANL data line, respectively, the first CAN transceiver 110 is in a correctly connected state with the CAN bus, and the second CAN transceiver 120 is in an incorrectly connected state with the CAN bus. If the first data line and the second data line are the CANL data line and the CANH data line, respectively, the first CAN transceiver 110 is in an incorrectly connected state with the CAN bus, and the second CAN transceiver 120 is in a correctly connected state with the CAN bus.

[0041] In a possible implementation, when the CAN transceiver is in low-power mode (or standby mode), the RXD port of the CAN transceiver continuously outputs a high level. When there is a specific wake-up signal on the CAN bus, if the CAN transceiver is correctly connected to the CAN bus, the CAN transceiver can be triggered by the wake-up signal to switch from low-power mode to normal mode, and output a low level at the RXD port; if the CAN transceiver is incorrectly connected to the CAN bus, the CAN transceiver cannot be awakened by the wake-up signal, and the RXD port maintains a high level output.

[0042] Specifically, Figure 2 Schematic diagram of the internal functional module structure of the CAN transceiver. Among them, the TXD port is the transmitting end pin of the CAN transceiver, the RXD port is the receiving end pin of the CAN transceiver, and the CANH port and the CANL port are the CAN bus end pins of the CAN transceiver. The transmission link of the CAN transceiver is formed from the TXD port to the CANH port and the CANL port. The data on the CAN bus can also be transmitted to the receiver module through the CANH port and the CANL port. The output of the receiver module is connected to the multiplexer module and finally outputs the signal input from the CAN bus to the CAN controller 140 through the RXD port. Among them, in order to avoid the continuous dominant signal input from the TXD port interfering with the operation on the CAN bus, the data input from the TXD port must first be detected by the dominant timeout module for the data input from the TXD port, and then transmitted to the driver module. The output of the driver module is connected to the CANH port and the CANL end port of the bus through the PMOS tube and the NMOS tube, respectively, and the data output by the driver module is transmitted to the bus through the CANH port and the CANL port. Figure 1 or Figure 2 In the figure, R1 and R2 are the terminal resistors of the CAN bus, which are used to improve the anti-interference ability of the CAN bus and quickly pass high-frequency and low-energy signals.

[0043] In order to reduce the power consumption of the chip, the CAN transceiver will enter low power mode. In low power mode, the sending and receiving functions of the CAN transceiver will be turned off, and only a wake-up monitoring function will be retained. In low power mode, the data input by the CANH port and the CANL port will be transmitted to the wake-up receiver, and then the wake-up receiver will judge the data. The CAN transceiver can be awakened only if and when the CANH port and the CANL port input a specific wake-up signal. Normally, when the CAN transceiver is in low power mode, the RXD port will always output a high-level signal. When the CAN bus inputs a wake-up signal and wakes up the CAN transceiver, if the CAN bus continues to input a dominant signal, the RXD port of the CAN transceiver will output Figure 3 The low level signal is shown.

[0044] In one possible implementation, the wake-up signal is as follows: Figure 4 As shown. Figure 4 As shown in the figure, the wake-up signal is a signal obtained by differentially connecting the differential signal pair of the CANH data line and the CANL data line. Figure 4 The dominant-recessive-dominant waveform shown in the figure can wake up the CAN transceiver. Among them, tdom1 is the first dominant time, trec is the middle recessive time, tdom2 is the second dominant time, and tdom1, tdom2 and trec must meet the predetermined time length to wake up the CAN transceiver.

[0045] Therefore, the detection module 130 can combine the first signal and / or the second signal triggered by the wake-up signal of the first CAN transceiver 110 and / or the second CAN transceiver 120 in the low power consumption mode to determine whether the first CAN transceiver 110 and the second CAN transceiver 120 are correctly connected to the CAN bus respectively.

[0046] In a possible implementation, the first signal and / or the second signal may be compared with the third signal, and if the third signal is the same, it is determined that the corresponding transmitter is correctly connected to the CAN bus. The third signal may be a signal of the RXD port after the CAN transceiver is awakened by the awakening signal.

[0047] In one possible implementation, since the first CAN transceiver 110 and the second CAN transceiver 120 are connected to the CAN bus in different directions, whether the connection between the first CAN transceiver 110 and the second CAN transceiver 120 is correct can be determined using only one of the first signal and the second signal.

[0048] For example, if the first signal is at a low level, it can be determined that the first CAN transceiver 110 is correctly connected to the CAN bus. If the second signal is at a low level, it can be determined that the second CAN transceiver 120 is correctly connected to the CAN bus.

[0049] In a possible implementation, the first signal and the second signal may be combined to determine whether the connection between the first CAN transceiver 110 and the second CAN transceiver 120 is correct. In this way, the accuracy of the judgment may be improved and the misjudgment caused by judging only by one signal may be reduced.

[0050] In a possible implementation, the detection module 130 may indicate whether the first CAN transceiver 110 and / or the second CAN transceiver 120 is correctly connected to the CAN bus by outputting a specific signal and / or information.

[0051] In a possible implementation, the control module may control the first CAN transceiver 110 and the second CAN transceiver 120 to enter a low power consumption mode, and send a wake-up signal on the CAN bus.

[0052] In a possible implementation, the control module may send a wake-up signal to the CAN bus through other CAN controllers 140 and CAN transceivers.

[0053] In one possible implementation, the control module, the first CAN transceiver 110, the second CAN transceiver 120 and the detection module 130 may be different functional modules located in the same integrated circuit chip. The control module, the first CAN transceiver 110, the second CAN transceiver 120 and the detection module 130 may be implemented by an integrated circuit.

[0054] Exemplarily, when the connection status of the CAN bus needs to be monitored, the first CAN transceiver 110 and the second CAN transceiver 120 can be made to enter a low power consumption mode. After the first CAN transceiver 110 and the second CAN transceiver 120 enter the low power consumption mode, a wake-up signal is sent to the two CAN transceivers through the CAN bus. If the CAN bus is correctly connected to the CANH port and the CANL port of the first CAN transceiver 110, that is, the CANH port of the first CAN transceiver 110 is connected to the CANH data line, and the CANL port of the first CAN transceiver 110 is connected to the CANL data line, the wake-up signal will wake up the first CAN transceiver 110 (the first signal output at the first RXD port is a low level); at this time, because the CAN bus is incorrectly connected to the CANH port and the CANL port of the second CAN transceiver 120, the second CAN transceiver 120 will not be awakened (the second signal output at the second RXD port is a high level). Correspondingly, if the CAN bus is correctly connected to the CANH port and the CANL port of the second CAN transceiver 120 , the second CAN transceiver 120 will be effectively awakened, while the first CAN transceiver 110 will not be awakened.

[0055] In this way, based on the fact that the RXD port of the CAN transceiver will generate a specific signal after being awakened, by connecting the first CAN transceiver 110 and the second CAN transceiver 120 to the CAN bus in opposite ways, the first signal and the second signal of the first CAN transceiver 110 and the second CAN transceiver 120 are triggered based on the wake-up signal on the CAN bus. Without manual troubleshooting, it is possible to determine whether the connection between the first CAN transceiver 110 and the second CAN transceiver 120 and the CAN bus is correct, thereby being able to detect faults in a timely manner and reducing data transmission errors caused by errors in the CAN transceiver and the CAN bus.

[0056] In some embodiments, Figure 5 As shown, the detection module 130 includes: a first transmission gate TG1, wherein The negative logic control terminal of the first transmission gate TG1 is connected to the first RXD port; The positive logic control terminal of the first transmission gate TG1 is connected to the second RXD port; The input end of the first transmission gate TG1 is used to input a predetermined signal; The output end of the first transmission gate TG1 is used to output a judgment signal, wherein, when the level of the judgment signal is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver 110 and the CAN bus is correct and / or the connection between the second CAN transceiver 120 and the CAN bus is incorrect; when the level of the judgment signal is different from the predetermined signal, it indicates that the connection between the first CAN transceiver 110 and the CAN bus is incorrect and / or the connection between the second CAN transceiver 120 and the CAN bus is correct.

[0057] The first transmission gate TG1 is Figure 5 As shown, since the first signal and the second signal are two signals of opposite levels, the first signal and the second signal can be used to control the control end of the first transmission gate TG1. The states of the first signal and the second signal are determined by judging whether the input end and the output end of the first transmission gate TG1 are consistent.

[0058] The connection between the RXD port and the control end of the first transmission gate TG1 can be adjusted according to actual needs.

[0059] In this embodiment, the first RXD port is connected to the negative logic control end of the first transmission gate TG1, and the second RXD port is connected to the positive logic control end of the first transmission gate TG1. Then, only when the first signal is at a low level (that is, the connection between the first CAN transceiver 110 and the CAN bus is correct) and the second signal is at a high level (that is, the connection between the second CAN transceiver 120 and the CAN bus is wrong), the predetermined signal can be output through the first transmission gate TG1, that is, the predetermined signal and the judgment signal are the same. Otherwise, the predetermined signal cannot be output through the first transmission gate TG1, that is, the predetermined signal and the judgment signal are different. It can be understood that when the detection module 130 outputs the judgment signal that is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver 110 and the CAN bus is correct, and the connection between the second CAN transceiver 120 and the CAN bus is wrong. When the detection module 130 does not output a judgment signal that is different from the predetermined signal, it indicates that the connection between the second CAN transceiver 120 and the CAN bus is correct, and the connection between the first CAN transceiver 110 and the CAN bus is wrong.

[0060] In a possible implementation, the predetermined signal may be a high level signal or a low level signal. When the predetermined signal is a high level signal, a pull-down resistor may be provided at the output end of the first transmission gate TG1, so that when the first transmission gate TG1 is not turned on, the output end of the first transmission gate TG1 maintains a low level, thereby reducing false indications. When the predetermined signal is a low level signal, a pull-up resistor may be provided at the output end of the first transmission gate TG1, so that when the first transmission gate TG1 is not turned on, the output end of the first transmission gate TG1 maintains a high level, thereby reducing false indications.

[0061] In a possible implementation manner, the predetermined signal may include a power supply voltage signal.

[0062] The first transmission gate TG1 can be used to indicate the states of the first signal and the second signal by using the high and low levels of the judgment signal, and the circuit structure is simplified.

[0063] In some embodiments, Figure 6 As shown, the detection module 130 further includes: an inverter NG1 and a second transmission gate TG2, wherein: The inverter NG1 is used to input the enable signal of the detection module 130 and output an inverted enable signal; The input terminal of the second transmission gate TG2 is used to input a predetermined signal; The enable signal and the inverted enable signal are used to control the on and off of the second transmission gate TG2; When the enable signal is enabled, the second transmission gate TG2 is controlled to be turned on so that the second transmission gate TG2 outputs the predetermined signal to the input end of the first transmission gate TG1.

[0064] Here, the enable signal may be sent by a control module, etc., to instruct the detection module 130 to indicate the phases of the first signal and the second signal.

[0065] In a possible implementation, the enable signal may be a high level signal or a low level signal.

[0066] The enable signal is converted into an inverted enable signal through the inverter NG1 , and the enable signal and the inverted enable signal are used to control the on and off of the second transmission gate TG2 .

[0067] Figure 6 In the circuit shown, the enable signal is a high-level signal. The enable signal is input through the inverter NG1 to obtain a low-level inverted enable signal which is input to the negative logic control terminal of the second transmission gate TG2. The enable signal is input to the positive logic control terminal of the second transmission gate TG2, thereby turning on the second transmission gate TG2 to input a predetermined signal to the input terminal of the first transmission gate TG1.

[0068] It is understandable that if the enable signal is a low level signal, the enable signal can be input to the negative logic control terminal of the second transmission gate TG2, and the inverted enable signal can be input to the positive logic control terminal of the second transmission gate TG2.

[0069] The detection module 130 is enabled through the second transmission gate TG2 , and the first transmission gate TG1 can be used to indicate the states of the first signal and the second signal by using the high and low levels of the judgment signal, thereby simplifying the circuit structure.

[0070] In some embodiments, Figure 7 As shown, the CAN interface circuit further includes: a CAN controller 140 and a selection module 150; The selection module 150 is used for at least one of the following: When the connection between the first CAN transceiver 110 and the CAN bus is correct, switching on the connection between the CAN controller 140 and the first CAN transceiver 110 and switching off the connection between the CAN controller 140 and the second CAN transceiver 120; When the connection between the second CAN transceiver 120 and the CAN bus is correct, the connection between the CAN controller 140 and the second CAN transceiver 120 is turned on, and the connection between the CAN controller 140 and the first CAN transceiver 110 is turned off.

[0071] Here, enabling the connection between the CAN controller 140 and the CAN transceiver (the first CAN transceiver 110 or the second CAN transceiver 120) may include connecting the connection between the TXD port of the CAN controller 140 and the TXD port of the CAN transceiver, and connecting the connection between the RXD port of the CAN controller 140 and the RXD port of the CAN transceiver. Disabling the connection between the CAN controller 140 and the CAN transceiver (the first CAN transceiver 110 or the second CAN transceiver 120) may include disconnecting the connection between the TXD port of the CAN controller 140 and the TXD port of the CAN transceiver, and disconnecting the connection between the RXD port of the CAN controller 140 and the RXD port of the CAN transceiver.

[0072] In a possible implementation, the selection may be controlled by a determination signal outputted from a control terminal of the first transmission gate TG1 to implement control of the selection module 150 so as to select the first CAN transceiver 110 or the second CAN transceiver 120 .

[0073] For example, the selection module 150 has an input terminal, and when a high level is input to the input terminal, the connection between the CAN controller 140 and the first CAN transceiver 110 is turned on. Therefore, when the judgment signal is at a high level indicating that the first CAN transceiver 110 is correctly connected to the CAN bus, the selection module 150 is also controlled by the judgment signal to turn on the connection between the CAN controller 140 and the first CAN transceiver 110.

[0074] In a possible implementation, the control module may control the selection module 150 based on the determination signal to select the first CAN transceiver 110 or the second CAN transceiver 120 .

[0075] In a possible implementation, the selection module 150 may use an electronic switch, a MOS tube, etc. to realize the connection on and off, which is not limited here.

[0076] In this way, the connection status between the CAN transceiver and the CAN bus can be determined through the CAN interface circuit, and the CAN bus communication can be utilized under different connection conditions, thereby improving the fault tolerance of the CAN interface circuit.

[0077] The present disclosure provides a CAN interface circuit, such as Figure 1 As shown, a CAN interface circuit comprises: a first CAN transceiver 110, a second CAN transceiver 120, a detection module 130 and a control module (not shown in Figure 1 ), where The first CANH port and the first CANL port of the first CAN transceiver 110 are used to connect to the first data line and the second data line in the CAN bus respectively; The second CANH port and the second CANL port of the second CAN transceiver 120 are used to connect to the second data line and the first data line respectively; A control module, used for controlling the first CAN transceiver 110 and the second CAN transceiver 120 to enter a low power consumption mode respectively, and generating a wake-up signal on the CAN bus when the first CAN transceiver 110 and the second CAN transceiver 120 are in the low power consumption mode respectively; The detection module 130 is used to indicate at least one of the following based on a first signal sent by the first RXD port of the first CAN transceiver 110 and / or a second signal sent by the second RXD port of the CAN transceiver: whether the connection between the first CAN transceiver 110 and the CAN bus is correct, and whether the connection between the second CAN transceiver 120 and the CAN bus is correct; wherein, the first signal is sent by the first CAN transceiver 110 in low power consumption mode in response to a wake-up signal on the CAN bus; and the second signal is sent by the second CAN transceiver 120 in low power consumption mode in response to the wake-up signal.

[0078] Here, the CANH port represents the high level signal port of the CAN bus, and the CANL port represents the low level signal port of the CAN bus. It can be understood that the CANH data line represents the high level signal data line of the CAN bus, and the CANL data line represents the low level signal data line of the CAN bus.

[0079] In a possible implementation, the first CAN transceiver 110 , the second CAN transceiver 120 , and the detection module 130 may belong to the same integrated circuit chip.

[0080] In a possible implementation, at least one of the first CAN transceiver 110 , the second CAN transceiver 120 and the detection module 130 is independent of the other items and does not belong to the same integrated circuit chip.

[0081] The functional components of CAN bus transmission include CAN controller 140 and CAN transceiver. CAN controller 140 is a hardware module used to control the sending and receiving of data frames on the CAN bus and is responsible for managing frame error handling. CAN controller 140 can exist independently or be integrated into a processor, microcontroller or embedded system. The independent CAN controller 140 communicates with the processor through the bus or peripheral interface, and can independently send and receive CAN bus data without the intervention of the processor.

[0082] The CAN transceiver is used to convert and adjust the signals between the CAN controller 140 and the physical layer of the CAN bus. The main function of the CAN transceiver is to convert the digital signal output by the CAN controller 140 into the physical signal required by the CAN bus, and to convert the physical signal received on the CAN bus into a digital signal and pass it to the CAN controller 140 for processing.

[0083] The CAN bus uses differential mode to transmit data. CAN can have two data lines: CANH data line and CANL data line for transmitting a pair of differential signals.

[0084] The CAN transceiver is used to connect to the CANH data line and CANL data line of the CAN bus through the CANH port and the CANL port respectively, and is connected to the CAN controller 140 through the receiving (RXD) port and the transmitting (TXD) port to realize signal conversion and adjustment between the CAN controller 140 and the physical layer of the CAN bus.

[0085] The first data line and the second data line may be two data lines of a CAN bus. The first data line and the second data line may be a CANH data line and a CANL data line respectively; the first data line and the second data line may also be a CANL data line and a CANH data line respectively.

[0086] Here, the first CAN transceiver 110 and the second CAN transceiver 120 are used to connect to the CAN bus in different connection modes, that is, one of the first CAN transceiver 110 and the second CAN transceiver 120 must be correctly connected to the CAN bus, while the other CAN transceiver is incorrectly connected to the CAN bus.

[0087] For example, if the first data line and the second data line are the CANH data line and the CANL data line, respectively, the first CAN transceiver 110 is in a correctly connected state with the CAN bus, and the second CAN transceiver 120 is in an incorrectly connected state with the CAN bus. If the first data line and the second data line are the CANL data line and the CANH data line, respectively, the first CAN transceiver 110 is in an incorrectly connected state with the CAN bus, and the second CAN transceiver 120 is in a correctly connected state with the CAN bus.

[0088] In a possible implementation, when the CAN transceiver is in low-power mode (or standby mode), the RXD port of the CAN transceiver continuously outputs a high level. When there is a specific wake-up signal on the CAN bus, if the CAN transceiver is correctly connected to the CAN bus, the CAN transceiver can be triggered by the wake-up signal to switch from low-power mode to normal mode, and output a low level at the RXD port; if the CAN transceiver is incorrectly connected to the CAN bus, the CAN transceiver cannot be awakened by the wake-up signal, and the RXD port maintains a high level output.

[0089] Specifically, Figure 2 Schematic diagram of the internal functional module structure of the CAN transceiver. Among them, the TXD port is the transmitting end pin of the CAN transceiver, the RXD port is the receiving end pin of the CAN transceiver, and the CANH port and the CANL port are the CAN bus end pins of the CAN transceiver. The transmission link of the CAN transceiver is formed from the TXD port to the CANH port and the CANL port. The data on the CAN bus can also be transmitted to the receiver module through the CANH port and the CANL port. The output of the receiver module is connected to the multiplexer module and finally outputs the signal input from the CAN bus to the CAN controller 140 through the RXD port. Among them, in order to avoid the continuous dominant signal input from the TXD port interfering with the operation on the CAN bus, the data input from the TXD port must first be detected by the dominant timeout module for the data input from the TXD port, and then transmitted to the driver module. The output of the driver module is connected to the CANH port and the CANL end port of the bus through the PMOS tube and the NMOS tube, respectively, and the data output by the driver module is transmitted to the bus through the CANH port and the CANL port.

[0090] In order to reduce the power consumption of the chip, the CAN transceiver will enter low power mode. In low power mode, the sending and receiving functions of the CAN transceiver will be turned off, and only a wake-up monitoring function will be retained. In low power mode, the data input by the CANH port and the CANL port will be transmitted to the wake-up receiver, and then the wake-up receiver will judge the data. The CAN transceiver can be awakened only if and when the CANH port and the CANL port input a specific wake-up signal. Normally, when the CAN transceiver is in low power mode, the RXD port will always output a high-level signal. When the CAN bus inputs a wake-up signal and wakes up the CAN transceiver, if the CAN bus continues to input a dominant signal, the RXD port of the CAN transceiver will output Figure 3 The low level signal is shown.

[0091] In one possible implementation, the wake-up signal is as follows: Figure 4 As shown. Figure 4 As shown in the figure, the wake-up signal is a signal obtained by differentially connecting the differential signal pair of the CANH data line and the CANL data line. Figure 4 The dominant-recessive-dominant waveform shown in the figure can wake up the CAN transceiver. Among them, tdom1 is the first dominant time, trec is the middle recessive time, tdom2 is the second dominant time, and tdom1, tdom2 and trec must meet the predetermined time length to wake up the CAN transceiver.

[0092] Therefore, the detection module 130 can combine the first signal and / or the second signal triggered by the wake-up signal of the first CAN transceiver 110 and / or the second CAN transceiver 120 in the low power consumption mode to determine whether the first CAN transceiver 110 and the second CAN transceiver 120 are correctly connected to the CAN bus respectively.

[0093] In a possible implementation, the first signal and / or the second signal may be compared with the third signal, and if the third signal is the same, it is determined that the corresponding transmitter is correctly connected to the CAN bus. The third signal may be a signal of the RXD port after the CAN transceiver is awakened by the awakening signal.

[0094] In one possible implementation, since the first CAN transceiver 110 and the second CAN transceiver 120 are connected to the CAN bus in different directions, whether the connection between the first CAN transceiver 110 and the second CAN transceiver 120 is correct can be determined using only one of the first signal and the second signal.

[0095] For example, if the first signal is at a low level, it can be determined that the first CAN transceiver 110 is correctly connected to the CAN bus. If the second signal is at a low level, it can be determined that the second CAN transceiver 120 is correctly connected to the CAN bus.

[0096] In a possible implementation, the first signal and the second signal may be combined to determine whether the connection between the first CAN transceiver 110 and the second CAN transceiver 120 is correct. In this way, the accuracy of the judgment may be improved and the misjudgment caused by judging only by one signal may be reduced.

[0097] In a possible implementation, the detection module 130 may indicate whether the first CAN transceiver 110 and / or the second CAN transceiver 120 is correctly connected to the CAN bus by outputting a specific signal and / or information.

[0098] In a possible implementation, the control module may control the first CAN transceiver 110 and the second CAN transceiver 120 to enter a low power consumption mode, and send a wake-up signal on the CAN bus.

[0099] In a possible implementation, the control module may send a wake-up signal to the CAN bus through other CAN controllers 140 and CAN transceivers.

[0100] In one possible implementation, the control module, the first CAN transceiver 110, the second CAN transceiver 120 and the detection module 130 may be different functional modules located in the same integrated circuit chip. The control module, the first CAN transceiver 110, the second CAN transceiver 120 and the detection module 130 may be implemented by an integrated circuit.

[0101] Exemplarily, when the connection status of the CAN bus needs to be monitored, the first CAN transceiver 110 and the second CAN transceiver 120 can be made to enter a low power consumption mode. After the first CAN transceiver 110 and the second CAN transceiver 120 enter the low power consumption mode, a wake-up signal is sent to the two CAN transceivers through the CAN bus. If the CAN bus is correctly connected to the CANH port and the CANL port of the first CAN transceiver 110, that is, the CANH port of the first CAN transceiver 110 is connected to the CANH data line, and the CANL port of the first CAN transceiver 110 is connected to the CANL data line, the wake-up signal will wake up the first CAN transceiver 110 (the first signal output at the first RXD port is a low level); at this time, because the CAN bus is incorrectly connected to the CANH port and the CANL port of the second CAN transceiver 120, the second CAN transceiver 120 will not be awakened (the second signal output at the second RXD port is a high level). Correspondingly, if the CAN bus is correctly connected to the CANH port and the CANL port of the second CAN transceiver 120 , the second CAN transceiver 120 will be effectively awakened, while the first CAN transceiver 110 will not be awakened.

[0102] In this way, based on the fact that the RXD port of the CAN transceiver will generate a specific signal after being awakened, by connecting the first CAN transceiver 110 and the second CAN transceiver 120 to the CAN bus in opposite ways, the first signal and the second signal of the first CAN transceiver 110 and the second CAN transceiver 120 are triggered based on the wake-up signal on the CAN bus. Without manual troubleshooting, it is possible to determine whether the connection between the first CAN transceiver 110 and the second CAN transceiver 120 and the CAN bus is correct, thereby being able to detect faults in a timely manner and reducing data transmission errors caused by errors in the CAN transceiver and the CAN bus.

[0103] In some embodiments, Figure 5 As shown, the detection module 130 includes: a first transmission gate TG1, wherein The negative logic control terminal of the first transmission gate TG1 is connected to the first RXD port; The positive logic control terminal of the first transmission gate TG1 is connected to the second RXD port; The input end of the first transmission gate TG1 is used to input a predetermined signal; The output end of the first transmission gate TG1 is used to output a judgment signal, wherein, when the level of the judgment signal is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver 110 and the CAN bus is correct and / or the connection between the second CAN transceiver 120 and the CAN bus is incorrect; when the level of the judgment signal is different from the predetermined signal, it indicates that the connection between the first CAN transceiver 110 and the CAN bus is incorrect and / or the connection between the second CAN transceiver 120 and the CAN bus is correct.

[0104] The first transmission gate TG1 is Figure 5 As shown in , since the first signal and the second signal are two signals of opposite levels, the first signal and the second signal can be used to control the control end of the first transmission gate TG1. The states of the first signal and the second signal are determined by judging whether the input end and the output end of the first transmission gate TG1 are consistent.

[0105] The connection between the RXD port and the control end of the first transmission gate TG1 can be adjusted according to actual needs.

[0106] In this embodiment, the first RXD port is connected to the negative logic control end of the first transmission gate TG1, and the second RXD port is connected to the positive logic control end of the first transmission gate TG1. Then, only when the first signal is at a low level (that is, the connection between the first CAN transceiver 110 and the CAN bus is correct) and the second signal is at a high level (that is, the connection between the second CAN transceiver 120 and the CAN bus is wrong), the predetermined signal can be output through the first transmission gate TG1, that is, the predetermined signal and the judgment signal are the same. Otherwise, the predetermined signal cannot be output through the first transmission gate TG1, that is, the predetermined signal and the judgment signal are different. It can be understood that when the detection module 130 outputs the judgment signal that is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver 110 and the CAN bus is correct, and the connection between the second CAN transceiver 120 and the CAN bus is wrong. When the detection module 130 does not output a judgment signal that is different from the predetermined signal, it indicates that the connection between the second CAN transceiver 120 and the CAN bus is correct, and the connection between the first CAN transceiver 110 and the CAN bus is wrong.

[0107] In a possible implementation, the predetermined signal may be a high level signal or a low level signal. When the predetermined signal is a high level signal, a pull-down resistor may be provided at the output end of the first transmission gate TG1, so that when the first transmission gate TG1 is not turned on, the output end of the first transmission gate TG1 maintains a low level, thereby reducing false indications. When the predetermined signal is a low level signal, a pull-up resistor may be provided at the output end of the first transmission gate TG1, so that when the first transmission gate TG1 is not turned on, the output end of the first transmission gate TG1 maintains a high level, thereby reducing false indications.

[0108] In a possible implementation manner, the predetermined signal may include a power supply voltage signal.

[0109] The first transmission gate TG1 can be used to indicate the states of the first signal and the second signal by using the high and low levels of the judgment signal, and the circuit structure is simplified.

[0110] In some embodiments, Figure 6 As shown, the detection module 130 further includes: an inverter NG1 and a second transmission gate TG2, wherein: The control module is further configured to output an enable signal of the detection module 130 to the inverter NG1; The inverter NG1 is used to output an inverted enable signal based on the enable signal; The input terminal of the second transmission gate TG2 is used to input a predetermined signal; The enable signal and the inverted enable signal are used to control the on and off of the second transmission gate TG2; When the enable signal is enabled, the second transmission gate TG2 is controlled to be turned on so that the second transmission gate TG2 outputs the predetermined signal to the input end of the first transmission gate TG1.

[0111] Here, the enable signal may be sent by a control module, etc., to instruct the detection module 130 to indicate the phases of the first signal and the second signal.

[0112] In a possible implementation, the enable signal may be a high level signal or a low level signal.

[0113] The enable signal is converted into an inverted enable signal through the inverter NG1 , and the enable signal and the inverted enable signal are used to control the on and off of the second transmission gate TG2 .

[0114] Figure 6 In the circuit shown, the enable signal is a high-level signal. The enable signal is input through the inverter NG1 to obtain a low-level inverted enable signal which is input to the negative logic control terminal of the second transmission gate TG2. The enable signal is input to the positive logic control terminal of the second transmission gate TG2, thereby turning on the second transmission gate TG2 to input a predetermined signal to the input terminal of the first transmission gate TG1.

[0115] It is understandable that if the enable signal is a low level signal, the enable signal can be input to the negative logic control terminal of the second transmission gate TG2, and the inverted enable signal can be input to the positive logic control terminal of the second transmission gate TG2.

[0116] The detection module 130 is enabled through the second transmission gate TG2 , and the first transmission gate TG1 can be used to indicate the states of the first signal and the second signal by using the high and low levels of the judgment signal, thereby simplifying the circuit structure.

[0117] In some embodiments, Figure 7 As shown, the CAN interface circuit further includes: a CAN controller 140 and a selection module 150; The controller is used for at least one of the following: When the connection between the first CAN transceiver 110 and the CAN bus is correct, control the selection module 150 to enable the connection between the CAN controller 140 and the first CAN transceiver 110, and to disable the connection between the CAN controller 140 and the second CAN transceiver 120; When the connection between the second CAN transceiver 120 and the CAN bus is correct, the selection module 150 is controlled to enable the connection between the CAN controller 140 and the second CAN transceiver 120 , and to disable the connection between the CAN controller 140 and the first CAN transceiver 110 .

[0118] Here, enabling the connection between the CAN controller 140 and the CAN transceiver (the first CAN transceiver 110 or the second CAN transceiver 120) may include connecting the connection between the TXD port of the CAN controller 140 and the TXD port of the CAN transceiver, and connecting the connection between the RXD port of the CAN controller 140 and the RXD port of the CAN transceiver. Disabling the connection between the CAN controller 140 and the CAN transceiver (the first CAN transceiver 110 or the second CAN transceiver 120) may include disconnecting the connection between the TXD port of the CAN controller 140 and the TXD port of the CAN transceiver, and disconnecting the connection between the RXD port of the CAN controller 140 and the RXD port of the CAN transceiver.

[0119] In a possible implementation, the selection may be controlled by a determination signal outputted from a control terminal of the first transmission gate TG1 to implement control of the selection module 150 so as to select the first CAN transceiver 110 or the second CAN transceiver 120 .

[0120] For example, the selection module 150 has an input terminal, and when a high level is input to the input terminal, the connection between the CAN controller 140 and the first CAN transceiver 110 is turned on. Therefore, when the judgment signal is at a high level indicating that the first CAN transceiver 110 is correctly connected to the CAN bus, the selection module 150 is also controlled by the judgment signal to turn on the connection between the CAN controller 140 and the first CAN transceiver 110.

[0121] In a possible implementation, the control module may control the selection module 150 based on the determination signal to select the first CAN transceiver 110 or the second CAN transceiver 120 .

[0122] In a possible implementation, the selection module 150 may use an electronic switch, a MOS tube, etc. to realize the connection on and off, which is not limited here.

[0123] In this way, the connection status between the CAN transceiver and the CAN bus can be determined through the CAN interface circuit, and the CAN bus communication can be utilized under different connection conditions, thereby improving the fault tolerance of the CAN interface circuit.

[0124] The present application also provides an integrated circuit chip, including the CAN interface circuit described in any of the above embodiments. The implementation of the CAN interface circuit is the same as any of the above embodiments and will not be described in detail here.

[0125] The present application also provides an electrical device, such as an airbag system, and the CAN interface circuit described in any of the above embodiments or the integrated circuit chip described in any of the above embodiments.

[0126] In a possible implementation, the airbag system further includes an airbag.

[0127] The present application also provides a vehicle system, comprising a vehicle body and the airbag system described in any one of the above embodiments.

[0128] The various embodiments or implementation methods in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referenced to each other.

[0129] In the description of this specification, reference to "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A controller area network (CAN) interface circuit, characterized in that: The CAN interface circuit comprises: a first CAN transceiver, a second CAN transceiver and a detection module, wherein: The first CANH port and the first CANL port of the first CAN transceiver are used to connect to the first data line and the second data line in the CAN bus respectively; The second CANH port and the second CANL port of the second CAN transceiver are used to connect to the second data line and the first data line respectively; The detection module is used to indicate at least one of the following based on a first signal sent by the first RXD port of the first CAN transceiver and / or a second signal sent by the second RXD port of the CAN transceiver: whether the connection between the first CAN transceiver and the CAN bus is correct, and whether the connection between the second CAN transceiver and the CAN bus is correct; wherein, the first signal is sent by the first CAN transceiver in low power mode in response to a wake-up signal on the CAN bus; and the second signal is sent by the second CAN transceiver in low power mode in response to the wake-up signal.

2. The circuit according to claim 1, characterized in that The detection module comprises: a first transmission gate, wherein: The negative logic control terminal of the first transmission gate is connected to the first RXD port; The positive logic control terminal of the first transmission gate is connected to the second RXD port; The input end of the first transmission gate is used to input a predetermined signal; The output end of the first transmission gate is used to output a judgment signal, wherein when the level of the judgment signal is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is correct and / or the connection between the second CAN transceiver and the CAN bus is incorrect; when the level of the judgment signal is different from the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is incorrect and / or the connection between the second CAN transceiver and the CAN bus is correct.

3. The circuit according to claim 2, characterized in that The detection module further includes: an inverter and a second transmission gate, wherein: The inverter is used to input the enable signal of the detection module and output an inverted enable signal; The input terminal of the second transmission gate is used to input a predetermined signal; The enable signal and the inverted enable signal are used to control the on and off of the second transmission gate; When the enable signal is enabled, the second transmission gate is controlled to be turned on so that the second transmission gate outputs the predetermined signal to the input end of the first transmission gate.

4. The circuit according to any one of claims 1 to 3, characterized in that: The CAN interface circuit also includes: a CAN controller and a selection module; The selection module is used for at least one of the following: When the connection between the first CAN transceiver and the CAN bus is correct, switching on the connection between the CAN controller and the first CAN transceiver, and switching off the connection between the CAN controller and the second CAN transceiver; When the connection between the second CAN transceiver and the CAN bus is correct, the connection between the CAN controller and the second CAN transceiver is turned on, and the connection between the CAN controller and the first CAN transceiver is turned off.

5. A controller area network (CAN) interface circuit, characterized in that: The CAN interface circuit includes: a first CAN transceiver, a second CAN transceiver, a detection module and a control module, wherein: The first CANH port and the first CANL port of the first CAN transceiver are used to connect to the first data line and the second data line in the CAN bus respectively; The second CANH port and the second CANL port of the second CAN transceiver are used to connect to the second data line and the first data line respectively; A control module, configured to control the first CAN transceiver and the second CAN transceiver to enter a low power consumption mode respectively, and generate a wake-up signal on the CAN bus when the first CAN transceiver and the second CAN transceiver are in the low power consumption mode respectively; The detection module is used to indicate at least one of the following based on a first signal sent by the first RXD port of the first CAN transceiver and / or a second signal sent by the second RXD port of the CAN transceiver: whether the connection between the first CAN transceiver and the CAN bus is correct, and whether the connection between the second CAN transceiver and the CAN bus is correct; wherein, the first signal is sent by the first CAN transceiver in low power mode in response to a wake-up signal on the CAN bus; and the second signal is sent by the second CAN transceiver in low power mode in response to the wake-up signal.

6. The circuit according to claim 5, characterized in that The detection module comprises: a first transmission gate, wherein: The negative logic control terminal of the first transmission gate is connected to the first RXD port; The positive logic control terminal of the first transmission gate is connected to the second RXD port; The input end of the first transmission gate is used to input a predetermined signal; The output end of the first transmission gate is used to output a judgment signal, wherein when the level of the judgment signal is the same as the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is correct and / or the connection between the second CAN transceiver and the CAN bus is incorrect; when the level of the judgment signal is different from the predetermined signal, it indicates that the connection between the first CAN transceiver and the CAN bus is incorrect and / or the connection between the second CAN transceiver and the CAN bus is correct.

7. The circuit according to claim 6, characterized in that The detection module further includes: an inverter and a second transmission gate, wherein: The control module is further configured to output an enable signal of the detection module to the inverter; The inverter is used to output an inverted enable signal based on the enable signal; The input terminal of the second transmission gate is used to input a predetermined signal; The enable signal and the inverted enable signal are used to control the on and off of the second transmission gate; When the enable signal is enabled, the second transmission gate is controlled to be turned on so that the second transmission gate outputs the predetermined signal to the input end of the first transmission gate.

8. The circuit according to any one of claims 5 to 7, characterized in that: The CAN interface circuit also includes: a CAN controller and a selection module; The controller is used for at least one of the following: When the connection between the first CAN transceiver and the CAN bus is correct, controlling the selection module to enable the connection between the CAN controller and the first CAN transceiver, and to disable the connection between the CAN controller and the second CAN transceiver; When the connection between the second CAN transceiver and the CAN bus is correct, the selection module is controlled to enable the connection between the CAN controller and the second CAN transceiver, and to disable the connection between the CAN controller and the first CAN transceiver.

9. An integrated circuit chip, characterized in that: The integrated circuit chip comprises a driving circuit and the CAN interface circuit according to any one of claims 1 to 8.

10. An electrical device, characterized in that: The electrical equipment comprises: The CAN interface circuit according to any one of claims 1 to 9; or The integrated circuit chip of claim 9.

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