9.1 Application Information

The SN74HCS72 is an ideal device for taking a CAN wake-up request and converting it to a power supply enable due to its low power consumption and noise rejecting inputs, which eliminate false triggers. CAN communication can occur when the vehicle ignition is off. Therefore, many circuits are designed to work in a standby or low power mode. Because a CAN wake-up request causes the RX pin to pulse LOW, the SN74HCS72 will trigger off the falling edge enabling the power for the CAN controller. Then the CAN controller powers on for the incoming communication. When communications are finished, the controller sends a reset pulse to the SN74HCS72 and CAN transceiver putting the circuit back into a standby mode.