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Control area network (CAN) transceivers with automatic polarity detection

  • US 10,560,282 B2
  • Filed: 12/26/2017
  • Issued: 02/11/2020
  • Est. Priority Date: 05/31/2017
  • Status: Active Grant
First Claim
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1. A control area network (CAN) bus integrated circuit comprising:

  • CAN bus high and low terminals;

    a receive data terminal;

    a first CAN bus transceiver (601A) having normal and standby modes, the first CAN bus transceiver including;

    high (607) and low (609) CAN bus connections, the first CAN bus transceiver high CAN bus connection connected to the high CAN bus terminal and the first CAN bus transceiver low CAN bus connection (609) connected to the low CAN bus terminal;

    a first receiver (612A) having high and low inputs and an output, the first receiver high input connected to the high CAN bus connection and the first receiver low input connected to the low CAN bus connection;

    a first low power receiver (612A) having high and low inputs and an output, the first low power receiver high input connected to the high CAN bus connection and the first low power receiver low input connected to the low CAN bus connection;

    a first wake up logic monitor (620A) having an input coupled to the first low power receiver output and having an output, a wake up indication being provided on the output when the first wake up logic monitor detects a wake up pattern on the CAN bus;

    a second CAN bus transceiver (601B) having normal and standby modes, the second CAN bus transceiver including;

    high (607) and low (609) CAN bus connections, the second CAN bus transceiver high CAN bus connection connected to the low CAN bus terminal and the second CAN bus transceiver low CAN bus connection connected to the high CAN bus terminal;

    a second receiver (612B) having high and low inputs and an output, the receiver high input connected to the low CAN bus connection and the receiver low input connected to the high CAN bus connection;

    a second low power receiver (616B) having high and low inputs and an output, the second low power receiver high input connected to the low CAN bus connection and the second low power receiver low input connected to the high CAN bus connection;

    a second wake up logic monitor (620B) having an input coupled to the second low power receiver output and having an output, a wake up indication being provided on the output when the second wake up logic monitor detects a wake up pattern on the CAN bus;

    detection logic (618A) coupled to the first wake up logic monitor output and the second wake up logic monitor output to detect which of the first wake up logic monitor and the second wake up logic monitor provides a wake up indication and having an output of the detection;

    direction logic (618B) coupled to the detection logic and the first and second CAN bus transceivers to use the output of the detection logic to place the one of the first and second CAN bus transceivers that provided the wake up indication from the first or second wake up logic monitor into normal mode and to place the other of the first and second CAN bus transceivers into standby mode; and

    output circuitry (630) coupled to the receive data terminal, to the direction logic and to the outputs of the first and second receivers and providing a output CAN bus receive data signal from the one of the first and second CAN bus transceivers in normal mode to the receive data terminal.

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