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LTC2972

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TON_MAX_FAULT_RESPONSE Data Contents

BIT(S) SYMBOL

OPERATION

b[7:6] Ton_max_fault_response_

action

Response action:

00b: The unit continues operation without interruption.

01b-11b: The unit shuts down immediately or sequences off after TOFF_DELAY (See Mfr_config_track_enn).

After shutting down, the device responds according to the retry settings in bits [5:3].

b[5:3] Ton_max_fault_response_retry Response retry behavior:

000b: A zero value for the retry setting means that the unit does not attempt to restart. The output remains

disabled until the fault is cleared.

001b-111b: The PMBus device attempts to restart the number of times specified by the global Mfr_retry_

count[2:0] until it is commanded OFF (by the CONTROL pin or OPERATION command or both), bias power is

removed, or another fault condition causes the unit to shut down.

Changing the value might not take effect until the next off-then-on sequence on that channel.

b[2:0] Ton_max_fault_response_delay Hard coded to 000b: There is no additional deglitch delay applied to fault detection.

MFR_RETRY_DELAY

This command determines the retry interval when the LTC2972 is in retry mode in response to a fault condition. This

delay is counted using SHARE_CLK only. This delay is internally limited to 13.1 seconds, and rounded to the nearest

200µs. The read value of this command always returns what was last written and does not reflect internal limiting.

PMBus COMMAND DESCRIPTION

MR_RETRY_COUNT

The MFR_RETRY_COUNT is a global command that sets the number of retries attempted when any channel faults off

with its fault response retry field set to a non zero value.

In the event of multiple or recurring retry faults on the same channel the total number of retries equals MFR_RETRY_

COUNT. If a channel has not been faulted off for at least 16 seconds, its retry counter is cleared. Toggling a channel’s

CONTROL pin off then on or issuing OPERATION off then on commands will synchronously clear the retry count.

MFR_RETRY_COUNT Data Contents

BIT(S) SYMBOL

OPERATION

b[7:3] Reserved

Always returns zero.

b[2:0] Mfr_retry_count [2:0]

0: No retries:

1-6: Number of retries.

7: Infinite retries.

Changing the value might not take effect until the next off-then-on sequence on that channel.

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