LTC3883 Datasheet, PDF (86/112 Pages) Linear Technology – Single Phase Step-Down DC/DC Controller with Digital Power System Management

LTC3883/LTC3883-1
PMBus Command Details
IOUT_OC_FAULT_RESPONSE
The IOUT_OC_FAULT_RESPONSE command instructs the device on what action to take in response to an output
overcurrent fault. The data byte is in the format given in Table 7.
The device also:
• Sets the NONE_OF_THE_ABOVE bit in the STATUS_BYTE
• Sets the IOUT_OC bit in the STATUS_BYTE
• Sets the IOUT bit in the STATUS_WORD
• Sets the IOUT Overcurrent Fault bit in the STATUS_IOUT command, and
• Notifies the host by asserting ALERT pin
This command has one data byte.
Table 7. IOUT_OC_FAULT_RESPONSE Data Byte Contents
BITS DESCRIPTION
VALUE MEANING
7:6 Response
00 The LTC3883 continues to operate indefinitely while maintaining
For all values of bits [7:6], the LTC3883:
• Sets the corresponding fault bit in the status commands and
the output current at the value set by IOUT_OC_FAULT_LIMIT
without regard to the output voltage (known as constant-
current or brick-wall limiting).
• Notifies the host by asserting ALERT pin
01 Not supported.
The fault bit, once set, is cleared only when one or more of the
following events occurs:
• The device receives a CLEAR_FAULTS command
10 The LTC3883 continues to operate, maintaining the output
current at the value set by IOUT_OC_FAULT_LIMIT without
regard to the output voltage, for the delay time set by bits [2:0].
• The output is commanded through the RUN pin, the OPERATION
command, or the combined action of the RUN pin and
OPERATION command, to turn off and then to turn back on, or
If the device is still operating in current limit at the end of the
delay time, the device responds as programmed by the Retry
Setting in bits [5:3].
• Bias power is removed and reapplied to the LTC3883.
11 The LTC3883 shuts down immediately and responds as
programmed by the Retry Setting in bits [5:3].
5:3 Retry Setting
2:0 Delay Time
000 The unit does not attempt to restart. The output remains
disabled until the fault is cleared by cycling the RUN pin or
removing bias power.
111 The device attempts to restart continuously, without limitation,
until it is commanded OFF (by the RUN pin or OPERATION
command or both), bias power is removed, or another fault
condition causes the unit to shut down. Note: The retry interval
is set by the MFR_RETRY_DELAY command.
000-111 The number of delay time units in 16ms increments. This
delay time is used to determine the amount of time a unit is
to continue operating after a fault is detected before shutting
down. Only valid for deglitched off response.
Fault Responses IC Temperature
COMMAND NAME
MFR_OT_FAULT_
RESPONSE
CMD CODE DESCRIPTION
0xD6 Action to be taken by the device when an
internal overtemperature fault is detected
TYPE
R Byte
DATA
FORMAT
Reg
UNITS
DEFAULT
NVM VALUE
0xC0
3883f
86