6
Monitoring functions
The device incorporates various features for using the device as a supply backbone:
•
Integrated voltage monitors for the output voltages, see
•
Integrated window watchdog for supervising microcontroller timing, see
6.1
Voltage monitoring
6.1.1
Monitoring of R1VSx battery supply
If the battery voltage drops below
V
R1VSx,UV
, then the undervoltage monitoring feature for R1VSx sets the SPI
status flag
6.1.2
Monitoring of output voltages
The voltage monitoring function supervises the voltages on the feedback pins R1FB, R2FB and R3FB of the
switched-mode converters with respect to the thresholds for undervoltage and overvoltage, see
.
The device does not detect a signal as a fault event, which crosses the respective thresholds for a time shorter
than the deglitching time. When a signal crosses a threshold for a duration longer than the deglitching time,
then the device generates an undervoltage event or an overvoltage event. If the voltage is below the
undervoltage threshold for a duration longer than the short-to-ground detection time, then the device
generates a short-to-ground event in addition. The monitoring also features deep undervoltage detection for
Buck1 and Buck2. If the voltage on the feedback pins R1FB or R2FB drops below the deep undervoltage
threshold for a duration longer than the deglitching time, then the device generates a short-to-ground event.
Depending on the type of fault, the device executes appropriate according actions, see
.
When the device enables a power rail, it activates the respective voltage monitoring automatically. For
information on the behavior during power sequencing see
Power sequencing and soft start
6.1.3
Monitoring of external voltage rails
The device supports monitoring of two external voltage rails on the pins VM1FB, VM2FB. The device compares
external voltages using window comparators against predefined thresholds. These thresholds define levels
relative to the assumed nominal input voltage, see
. Resistor dividers are to be used to map the output
voltage of the respective voltage rail externally.
Signals crossing the thresholds for a time shorter than the deglitching time are not detected as a fault event.
When a signal crosses a threshold for a duration longer than the deglitching time, then the device generates an
undervoltage event or an overvoltage event. If the voltage is below the undervoltage threshold for a duration
longer than the short-to-ground detection time, then the device generates a short-to-ground event in addition.
Depending on the type of fault, the device executes appropriate according actions, see
.
When the device enables a power rail, it activates the respective voltage monitoring automatically. For
information on the behavior during power sequencing see
Power sequencing and soft start
If an overvoltage event or a short-to-ground event occurs, then the device shuts down the respective voltage rail
to protect the load and the device.
OPTIREG
™
PMIC TLF30681QVS01
Power management IC
Monitoring functions
Datasheet
47
Rev. 1.0
2020-04-08
