SFFS141 December   2021 TCAN1167-Q1

 

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5.3.2 Supply Voltage Rail Monitoring

There are two under voltage events monitored in the TCAN1167-Q1: VSUP and VCCOUT. VSUP is an input source for the TCAN1167-Q1, and VCCOUT is the LDO output that is used for the CAN transceiver as well as external power sourcing. These pins have have under voltage detection circuitry which places the device into a protected state if an under voltage fault occurs, UVSUP and UVCCOUT. This protects the bus during an under voltage event on these terminals. If VSUP is under voltage, the device loses the source needed to keep the internal regulators active. This causes the device to go into a state where communication between the microprocessor and the TCAN1167-Q1 is disabled. The TCAN1167-Q1 is not able to receive information from the bus; and thus, does not passs any signals from the bus, including any Bus Wake via BWRR signals to the microprocessor.

The following sections provide the functional safety mechanisms that cover the supply voltage rail monitoring: