Datasheet

MAX34451 PMBus 16-Channel V/I Monitor and
12-Channel Sequencer/Marginer
www.maximintegrated.com
Maxim Integrated │ 49
Table 29. Fault Monitoring States
Note: Device response to faults is determined by the configuration of MFR_FAULT_RESPONSE.
Fault Detection Before Power-On Sequencing
Beforeanypower-supplychannelisenabledorFAULTn
output deasserted, the device checks for overvoltage,
overcurrent, and overtemperature faults (but not for
undervoltage) if the channel is configured for a fault
responsetoeitherlatchoff(RESPONSE[1:0]=01)orretry
(RESPONSE[1:0]=10)intheMFR_FAULT_REPSONSE
command. Undervoltage faults are detected when the
power supply turns on and fails to reach the power-good
level,andtheTON_MAX_FAULT_LIMITisexceededand
thedevicetakesfaultactionasconfigured.SeeTable29.
Logging Faults into MFR_NV_FAULT_LOG
If bit 15 of MFR_FAULT_RESPONSE is set, faults are
logged into the on-board nonvolatile fault log for this chan-
nel unless the response for the associated fault is config-
uredtotakenoaction(RESPONSE[1:0]=00).Tokeep
from needlessly filling the fault log with excessive data,
the following rules are applied when subsequent faults
occur.Whenovervoltagefaultsoccurs,subsequentover-
voltage faults on this channel are not written to the fault
loguntileithertheCLEAR_FAULTScommandisissued
or a device reset occurs. The same rule applies to over-
current, undervoltage, overtemperature, and sequencing
faults(seeTable30andFigure10).
FAULT
REQUIRED DEVICE CONFIGURATION
FOR ACTIVE MONITORING
WHEN MONITORED
Overvoltage
•
VoltageMonitoringEnabled
(SELECT[5:0]=10hor20hinMFR_CHANNEL_CONFIG)
Continuous monitoring
Undervoltage
•
VoltageMonitoringEnabled
(SELECT[5:0]=10hor20hinMFR_CHANNEL_CONFIG)
Stopmonitoringwhilethepowersupplyis
off;startmonitoringwhenvoltageexceeds
thePOWER_GOOD_ONlevel
Overcurrent
• CurrentMonitoringEnabled
(SELECT[5:0]=22hinMFR_CHANNEL_CONFIG)
Continuous monitoring
Power-UpTime
• SequencingEnabled
(SELECT[5:0]=10hinMFR_CHANNEL_CONFIG)
Monitored only during power on sequence
Overtemperature
•
TemperatureSensorEnabled
(ENABLE=1inMFR_TEMP_SENSOR_CONFIG)
Continuous monitoring