• State
  • Locked Locked
  • Replies 5 replies
  • Subscribers 32 subscribers
  • Views 231 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TCAN330: CAN short to GND when communicating is on going

user6060721
Expert 1015 points
Part Number: TCAN330
Other Parts Discussed in Thread: TCAN1043-Q1

When I use TCAN330 connected two devices,

CANL connect to GND,communication is still normal，so system can not distinguish this failure.

What can we do to distinguish this failure.

And how to detect other failure modes?

Thanks.

  • 0
    TI__Guru 64472 points

    user,

    When this is implemented into transceivers, the method of detection is by measuring the difference in current from what is being sourced by CANH and what is being sunk by CANL. A current differential threshold is set and if that threshold is surpassed, a fault flag is asserted. This kind of function is featured on our TCAN1043-Q1. To implement this on TCAN330, external components would be needed, because there is no integrated circuitry on the transceiver and as you said, the controller has no indication that anything is wrong because communication continues.

    Please let me know if you have any questions.

    Regards,

  • 0 in reply to Eric Hackett
    Expert 1015 points

    TCAN1043-Q1 can distinguish CANH and CANL shrot or open？

    Or CANH、CANL short to VCC、Vbattery？

    Thanks.

  • 0 in reply to user6060721
    TI__Guru 64472 points

    User,

    No, the TCAN1043-Q1 will indicate that there is a bus fault that could be CANL short to GND on the nFAULT pin. There are 6 CAN bus faults that can occur that will toggle the nFAULT pin low in normal mode, but there is no specific indication of what the fault is since it is just a logic-level indication. 

    Some of our more advanced CAN transceivers have bus fault detection that allows the user to look up the specific fault in registers, but these transceivers are not fully released yet.

    Regards,

  • 0 in reply to Eric Hackett
    Expert 1015 points

    in TCAN330 datasheet:

    Receiver input threshold min 500mv,max 900mv,

    I can not understand when my input differential voltage is 600mv，is this OK？

  • 0 in reply to user6060721
    TI__Guru 64472 points

    User,

    600mV would be an indeterminate state, but CAN transceivers on the bus should not be driving this differential in the first place. If the CAN bus differential voltage is less than 900mV during a dominant phase, than there is likely some issue happening that is attenuating the overall differential signal.

    Regards,