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,
UV
SUP and UV
CCOUT. 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: