Datasheet

MAX34446

PMBus Power-Supply Data Logger

16Maxim Integrated

Figure 1. PGn and FAULTn Output After a Channel is Enabled

Fault Response When a Channel

is Enabled

Whenever a channel (voltage, current, or temperature)

is enabled (V

cycle, or hardware or software reset,

or by PMBus command) the channel’s FAULTn signal is

asserted if the FAULT_EN bits in MFR_FAULT_RESPONSE

are set so that the device responds to a fault or warn-

ing. If enabled, the FAULTn pin is not released until all

measurements pass. Also, prior to being allowed to set

a fault/warning status bit or write a nonvolatile fault log

when a fault/warning occurs, the channel must first pass

this particular fault or warning.

Figure 1 describes the steps that the MAX34446 takes

to monitor a channel after the channel is enabled.

Figure 2 explains how the MAX34446 responds after

a channel is enabled and as faults and warnings pass

and fail. Figure 2 shows a voltage channel and over-

voltage faults and warnings, but these same steps

apply to other monitored parameters as well.

RESET COMPLETE AND ENABLE PIN HIGH

DISABLE WRITES TO MFR_NV_FAULT_LOG

IF FAULT_EN ≠ 0X, ASSERT FAULTn PIN

FORCE PGn PINS LOW ON ALL CHANNELS CONFIGURED TO MONITOR VOLTAGE

(OTHER PGn PINS ARE HIGH IMPEDANCE)

MEASURE THE VOLTAGE/CURRENT/TEMPERATURE

ON VOLTAGE CHANNELS, IS THE MEASURED VOLTAGE > POWER_GOOD_ON?

IS THE MEASURED PARAMETER WITHIN FAULT LIMITS?

(ALSO INCLUDES WARNING LIMITS IF FAULT_EN = 11)

DEASSERT THE FAULTn PIN

YES

ENABLE WRITES TO MFR_NV_FAULT_LOG

REGULAR PARAMETER MONITORING BEGINS

SET PGn PIN HIGH

AFTER MFR_PG_DELAY