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EP-4376362-B1 - DISCONNECTING A CAN TRANSCEIVER FROM A CAN BUS

EP4376362B1EP 4376362 B1EP4376362 B1EP 4376362B1EP-4376362-B1

Inventors

  • VAN DIJK, LUCAS PIETER LODEWIJK
  • Kwakernaat, Gerald

Dates

Publication Date
20260506
Application Date
20221128

Claims (14)

  1. A Controller Area Network, CAN, transceiver (200), comprising: a transmit data, TXD, interface (202), a receive data, RXD, interface (204), a CAN BUS interface (206), a first control interface (208), a transmitter (210), a receiver (212), and a control unit (214), wherein a transmitter input (216) of the transmitter is coupled to the TXD interface for receiving a TXD signal, wherein a transmitter output (218) of the transmitter is coupled to the CAN BUS interface, wherein the receiver is coupled between the CAN BUS interface and the RXD interface, wherein the transmitter comprises a first driver path (220) comprising a first series circuit (222), which comprises a first switch unit (224) and a second switch unit (226), wherein the transmitter comprises a second driver path (228) comprising a second series circuit (230), which comprises a third switch unit (232) and a fourth switch unit (234), wherein the first driver path is coupled to a first terminal (236) of the CAN BUS interface and the second driver path is coupled to a second terminal (238) of the CAN BUS interface, wherein the transmitter comprises a driver unit (240) configured to control the first switch unit and the third switch unit based on the TXD signal, wherein the control unit is coupled to the first control interface for receiving a first control signal, wherein the control unit is coupled to at least one switch unit of the first driver path and to at least one switch unit of the second driver path to control the switch units coupled to the control unit, wherein the control unit is configured, if the first control signal represents a deactivation message, to deactivate at least one switch unit of each driver path, wherein the driver unit is coupled to a control terminal of the first switch unit via a first control signal path (250), wherein the transmitter comprising a seventh switch unit (252) integrated into the first control signal path, wherein the driver unit is coupled to a control terminal of the third switch unit via a second control signal path (254), wherein the transmitter comprises an eighth switch unit (256) integrated into the second control signal path, wherein the control unit is coupled to the seventh and eighth switch units to control the seventh and eighth switch units, and wherein the control unit is configured, if the first control signal represents the deactivation message, to deactivate the seventh and eighth switch units.
  2. The CAN transceiver according to the preceding claim, wherein the first driver path is coupled between a first voltage supply terminal (242) of the CAN transceiver and the first terminal of the CAN BUS interface, and wherein the second driver path is coupled between a second voltage supply terminal (244) of the CAN transceiver and the second terminal of the CAN BUS interface.
  3. The CAN transceiver according to any of the preceding claims, wherein the first driver path comprises a further, fifth switch unit (246) and the second driver path comprises a further, sixth switch unit (248).
  4. The CAN transceiver according to any of the preceding claims, wherein the control unit is coupled to the control terminal of the first switch unit via a ninth switch unit (258) to control the first switch unit, wherein the control unit is coupled to the control terminal of the third switch unit via a tenth switch unit (260) to control the third switch unit, and wherein the control unit is configured, if the first control signal represents the deactivation message, to deactivate the first and third switch units.
  5. The CAN transceiver according to any of the preceding claims, wherein the control unit is coupled to a control terminal of the second switch unit via an eleventh switch unit (262) to control the second switch unit, wherein the control unit is coupled to a control terminal of the fourth switch unit via a twelfth switch unit (264) to control the fourth switch unit, and wherein the control unit is configured, if the first control signal represents the deactivation message, to deactivate the second and fourth switch units.
  6. The CAN transceiver according to any of the preceding claims, wherein the first and second switch units of the first driver path are arranged such that along the first driver path the second switch unit is arranged closer than the first switch unit to the first terminal of the CAN BUS interface.
  7. The CAN transceiver according to the preceding claim, if additionally depending on claim 3, wherein the fifth and first switch units of the first driver path are arranged such that along the first driver path that the first switch unit is arranged closer than the fifth switch unit to the first terminal of the CAN BUS interface.
  8. The CAN transceiver according to any one of the preceding claims, wherein the third and fourth switch units of the second driver path are arranged such that along the second driver path the fourth switch unit is arranged closer than the third switch unit to the second terminal of the CAN BUS interface.
  9. The CAN transceiver according to the preceding claim, if additionally depending on claim 3, wherein the sixth and third switch units of the second driver path are arranged such that along the second driver path the third switch unit is arranged closer than the sixth switch unit to the second terminal of the CAN BUS interface.
  10. The CAN transceiver according to any of the preceding claims, wherein the TXD interface is coupled to a driver input (268) of the driver unit via the transmitter input and a TXD signal path (266), wherein the transmitter comprises a thirteenth switch unit (270) integrated with the TXD signal path, wherein the control unit is coupled to the thirteenth switch unit to control the thirteenth switch unit, and wherein the control unit is configured, if the first control signal represents the deactivation message, to deactivate the thirteenth switch unit.
  11. The CAN transceiver according to any one of the preceding claims, wherein the CAN transceiver comprises a second control interface (272), wherein the control unit is coupled to the second control interface to receive a second control signal, wherein the control unit is configured to control the CAN transceiver based on the second control signal.
  12. The CAN transceiver according to the preceding claim, if additionally dependent on claim 10, wherein the control unit is configured to activate the second, fourth, seventh, eighth, and thirteenth switch units if the second control signal represents an activated mode of operation and if the first control signal does not represent the deactivation message.
  13. The CAN transceiver according to any one of the preceding claims 11 to 12, if additionally dependent on claim 10, wherein the control unit is configured, if the second control signal represents a deactivated mode of operation and if the first control signal does not represent the deactivation message, to activate the second, fourth, seventh, and eighth switch units and to deactivate the thirteenth switch unit.
  14. A method for a Control Area Network, CAN, transceiver (200) comprising a transmit data, TXD, interface (202), a receive data, RXD, interface (204), a CAN BUS interface (206), a first control interface (208), a transmitter (210), a receiver (212), and a control unit (214), wherein a transmitter input (216) of the transmitter is coupled to the TXD interface to receive a TXD signal, wherein a transmitter output (218) of the transmitter is coupled to the CAN BUS interface, wherein the receiver is coupled between the CAN BUS interface and the RXD interface, wherein the transmitter comprises a first driver path (220) comprising a first series circuit (222), which comprises a first switch unit (224) and a second switch unit (226), wherein the transmitter comprises a second driver path (228) comprising a second series circuit (230), which comprises a third switch unit (232) and a fourth switch unit (234), wherein the first driver path is coupled to a first terminal (236) of the CAN BUS interface and the second driver path is coupled to a second terminal (238) of the CAN BUS interface, wherein the transmitter comprises a driver unit (240) configured to control the first switch unit and the third switch unit based on the TXD signal, wherein the control unit is coupled to the first control interface, wherein the control unit is coupled to at least one switch unit of the first driver path and to at least one switch unit of the second driver path, wherein the driver unit is coupled to a control terminal of the first switch unit via a first control signal path (250), wherein the transmitter comprising a seventh switch unit (252) integrated into the first control signal path, wherein the driver unit is coupled to a control terminal of the third switch unit via a second control signal path (254), wherein the transmitter comprises an eighth switch unit (256) integrated into the second control signal path, wherein the control unit is coupled to the seventh and eighth switch units to control the seventh and eighth switch units, wherein the method comprising the following steps: a) receiving a first control signal by the control unit via the first control interface; b) controlling by the control unit the switch units coupled to the control unit if the first control signal represents a deactivation message, such that at least one switch unit of each driver path is deactivated and such that the seventh and eighth switch units are deactivated.

Description

TECHNICAL FIELD The present disclosure relates to a Controller Area Network, CAN, Transceiver and a method for the CAN transceiver. BACKGROUND CAN buses can be used for communications within vehicles, in particular within automobiles. It will be appreciated that CAN buses also have application outside of the field of automobiles. A CAN bus network may include multiple bus devices, so called nodes or electronic control units (ECUs), such as an engine control module (ECM), a power train control module (PCM), airbags, antilock brakes, cruise control, electric power steering, audio systems, windows, doors, mirror adjustment, battery and recharging systems for hybrid/electric cars, and many more. A CAN protocol is used to enable communications between the various bus devices. The data link layer of the CAN protocol is standardized as International Standards Organization (ISO) 20698-1:2003. CAN Flexible Data-Rate or "CAN FD," which is an extension of the standardized CAN data link layer protocol and is meanwhile integrated into the ISO20698-1:2015 standard, can provide higher data rates. The standardized CAN data link layer protocol is being further extended to provide even higher data rates. A further extension, referred to as CAN XL, with a new level scheme allowing even higher data rates is in the definition phase discussed under CiA610 (CAN in Automation) and is moving towards standardization in the form of either a further update of the existing ISO20698 standards or a new standard. US 2004/153870 A1 relates to systems and methods for maintaining a communication in a network bus in the event of various types of bus failures including a short circuit condition, an open circuit condition or a network device that improperly occupies the network bus with meaningless data. SUMMARY The present invention is defined in the appended independent claims to which reference should be made. Advantageous features are set out in the appended dependent claims. DESCRIPTION OF DRAWINGS Embodiments of the present disclosure will be described in more detail with reference to the appended drawings. Figure 1 shows a simplified block diagram of a CAN System.Figure 2 shows a simplified block diagram of a CAN Node.Figure 3 shows a simplified block diagram of a CAN Transceiver.Figure 4 shows depicts a simplified flow chart of a method for the CAN transceiver. DESCRIPTION OF EMBODIMENTS Figure 1 schematically depicts an example of a CAN system 100 that is known in the field. The CAN system may include multiple CAN nodes 102 or "ECUs" 102, each connected to a CAN BUS network 104. In the embodiment of Figure 1, each CAN node 102 includes a microcontroller 108 and a CAN transceiver 200. The microcontroller 108 may be embedded in a microcontroller of the CAN node 102. The microcontroller 108 may be referred to as a microcontroller 108. The CAN transceiver 200 may be referred to as a transceiver 200. The microcontrollers 108 are typically connected directly or indirectly to at least device outside the system 100, such as an switch, a main controller, an actuator, or some other control device. The microcontrollers 108 are often programmed to determine the meaning of received messages and to generate appropriate outgoing messages. A processing unit 110 of a microcontroller 108 may also be referred to as host processors, hosts or digital signal processors (DSPs). In an embodiment, the processing unit of the microcontroller supports application software that interacts with the interfaces of the microcontroller 108. Each microcontroller 108 may have an embedded CAN Protocol controller 109, which may also be referred to as a CAN controller 109. The microcontrollers 108 may be configured to support application software that interacts with the CAN controller 109. The CAN BUS network 104 carries analog differential signals and includes a first CAN signal line 114, which is also referred to as the CAN high (CANH) bus line 114, and a second CAN signal line 116, which is also referred to as the CAN low (CANL) bus line 116. The CAN BUS network 104 is known in the field. Figure 2 depicts an expanded view of one CAN device 102 from Figure 1. In the expanded view of Figure 2, the microcontroller 108 comprises a processing unit 110, which may, for example, run a software application that is stored in a memory of the microcontroller 108 and executed by processing circuits of the microcontroller 108. The microcontroller 108 and the CAN transceiver 200 of the CAN device 102 are connected between a first supply voltage, VCC, and as second supply voltage, which is usually ground, GND. As illustrated in Figure 2, data communicated from microcontroller 108 to the CAN transceiver 200 is identified as transmit data (TXD) and data communicated from the CAN transceiver 200 to the microcontroller 108 is referred to as receive data (RXD). Throughout the description, TXD is carried on a TXD path and RXD is carried on an RXD path. The CAN transceiver comprises a BUS inter